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Sample records for current techniques based

  1. MPPT Technique Based on Current and Temperature Measurements

    Directory of Open Access Journals (Sweden)

    Eduardo Moreira Vicente

    2015-01-01

    Full Text Available This paper presents a new maximum power point tracking (MPPT method based on the measurement of temperature and short-circuit current, in a simple and efficient approach. These measurements, which can precisely define the maximum power point (MPP, have not been used together in other existing techniques. The temperature is measured with a low cost sensor and the solar irradiance is estimated through the relationship of the measured short-circuit current and its reference. Fast tracking speed and stable steady-state operation are advantages of this technique, which presents higher performance when compared to other well-known techniques.

  2. Non-Destructive Techniques Based on Eddy Current Testing

    Science.gov (United States)

    García-Martín, Javier; Gómez-Gil, Jaime; Vázquez-Sánchez, Ernesto

    2011-01-01

    Non-destructive techniques are used widely in the metal industry in order to control the quality of materials. Eddy current testing is one of the most extensively used non-destructive techniques for inspecting electrically conductive materials at very high speeds that does not require any contact between the test piece and the sensor. This paper includes an overview of the fundamentals and main variables of eddy current testing. It also describes the state-of-the-art sensors and modern techniques such as multi-frequency and pulsed systems. Recent advances in complex models towards solving crack-sensor interaction, developments in instrumentation due to advances in electronic devices, and the evolution of data processing suggest that eddy current testing systems will be increasingly used in the future. PMID:22163754

  3. Non-Destructive Techniques Based on Eddy Current Testing

    Directory of Open Access Journals (Sweden)

    Ernesto Vázquez-Sánchez

    2011-02-01

    Full Text Available Non-destructive techniques are used widely in the metal industry in order to control the quality of materials. Eddy current testing is one of the most extensively used non-destructive techniques for inspecting electrically conductive materials at very high speeds that does not require any contact between the test piece and the sensor. This paper includes an overview of the fundamentals and main variables of eddy current testing. It also describes the state-of-the-art sensors and modern techniques such as multi-frequency and pulsed systems. Recent advances in complex models towards solving crack-sensor interaction, developments in instrumentation due to advances in electronic devices, and the evolution of data processing suggest that eddy current testing systems will be increasingly used in the future.

  4. Non-destructive techniques based on eddy current testing.

    Science.gov (United States)

    García-Martín, Javier; Gómez-Gil, Jaime; Vázquez-Sánchez, Ernesto

    2011-01-01

    Non-destructive techniques are used widely in the metal industry in order to control the quality of materials. Eddy current testing is one of the most extensively used non-destructive techniques for inspecting electrically conductive materials at very high speeds that does not require any contact between the test piece and the sensor. This paper includes an overview of the fundamentals and main variables of eddy current testing. It also describes the state-of-the-art sensors and modern techniques such as multi-frequency and pulsed systems. Recent advances in complex models towards solving crack-sensor interaction, developments in instrumentation due to advances in electronic devices, and the evolution of data processing suggest that eddy current testing systems will be increasingly used in the future.

  5. Low current beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A.; Laird, J.S.; Bardos, R.A.; Legge, G.J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T.; Sekiguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan).

    1993-12-31

    Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

  6. Determination of confinement efficiency in tokamaks based on current independent flux loops technique

    Science.gov (United States)

    Salar Elahi, A.; Ghoranneviss, M.

    In this contribution we presented a current independent approximation of the combination of poloidal beta and internal inductance (confinement efficiency) only based on poloidal flux loops measurement in IR-T1 tokamak. The main advantage of this technique is that it based only on the one diagnostic (only flux loops and not need to plasma current measurement). Based on this method, two flux loops were designed, constructed, and installed on outer surface of the IR-T1 tokamak chamber and then the Shafranov parameter was measured from them. Also the result of this technique was compared with conventional magnetic probes technique and found in good agreement with each other.

  7. Hysteresis Current Control technique based on Space Vector Modulation for Active Power Filter

    Directory of Open Access Journals (Sweden)

    Wang Yun-liang

    2011-09-01

    Full Text Available In this paper, the hysteresis current control (HCC technique based on space vector modulation (SVM for shunt active power filter (APF is proposed. The switching control algorithms of the HCC based SVM manage to generate compensated current according to the reference current. Harmonics extraction is based on the instantaneous active and reactive power theorem in time domain by calculating the power compensation. A closed loop control system is carried out and the error current is the difference between the reference current which is obtained from the power compensation and the actual current needs to be injected back into the power grid. By implementing this control strategy, the APF manages to generate better compensated harmonics currents to the power grid. Keywords: active power filter, hysteresis current control, space vector modulation ,matlab/simulink

  8. Leakage Current Optimization Techniques During Test Based on Don't Care Bits Assignment

    Institute of Scientific and Technical Information of China (English)

    Wei Wang; Yu Hu; Yin-He Han; Xiao-Wei Li; You-Sheng Zhang

    2007-01-01

    It is a well-known fact that test power consumption may exceed that during functional operation. Leakage power dissipation caused by leakage current in Complementary Metal-Oxide-Semiconductor (CMOS) circuits during test has become a significant part of the total power dissipation. Hence, it is important to reduce leakage power to prolong battery life in portable systems which employ periodic self-test, to increase test reliability and to reduce test cost. This paper analyzes leakage current and presents a kind of leakage current simulator based on the transistor stacking effect.Using it, we propose techniques based on don't care bits (denoted by Xs) in test vectors to optimize leakage current in integrated circuit (IC) test by genetic algorithm. The techniques identify a set of don't care inputs in given test vectors and reassign specified logic values to the X inputs by the genetic algorithm to get minimum leakage vector (MLV).Experimental results indicate that the techniques can effectually optimize leakage current of combinational circuits and sequential circuits during test while maintaining high fault coverage.

  9. Pulse-driven LED circuit with transformer-based current balance technique

    Science.gov (United States)

    Kwak, S.-S.

    2014-12-01

    Light emitting diodes (LEDs) have been gradually used for backlight modules for liquid crystal display as a substitute for cold cathode fluorescent lamps. In most of LED applications, it is required to connect several LED strings in parallel to limit the dc voltage level to be applied to the single LED string. Due to considerable current variations through each LED string with inevitable parameter deviations as well as temperature and ageing effects, techniques to balance currents flowing through LED strings are required for LED drivers. This article proposes a pulse-driven LED circuit with transformer-based current balancing scheme, which can simply regulate currents through the LED strings. The transformers are placed in series with the LED strings in such a way that the LED currents are automatically balanced. Since the developed current sharing technique employs no dissipative resistors and no linear-mode transistors, the proposed driver has high efficiency, low power dissipation and reduced thermal problems. In addition, the presented driver with no additional semiconductor devices and no additional controllers can provide a simple and a cost-effective current balancing solution, compared to conventional approaches. Thus, the proposed LED driver can feature a simple, highly efficient, reliable and cost-effective method. The presented LED driver is verified with experimental results.

  10. An Eddy Current Testing Platform System for Pipe Defect Inspection Based on an Optimized Eddy Current Technique Probe Design

    Science.gov (United States)

    Rifai, Damhuji; Abdalla, Ahmed N.; Razali, Ramdan; Ali, Kharudin; Faraj, Moneer A.

    2017-01-01

    The use of the eddy current technique (ECT) for the non-destructive testing of conducting materials has become increasingly important in the past few years. The use of the non-destructive ECT plays a key role in the ensuring the safety and integrity of the large industrial structures such as oil and gas pipelines. This paper introduce a novel ECT probe design integrated with the distributed ECT inspection system (DSECT) use for crack inspection on inner ferromagnetic pipes. The system consists of an array of giant magneto-resistive (GMR) sensors, a pneumatic system, a rotating magnetic field excitation source and a host PC acting as the data analysis center. Probe design parameters, namely probe diameter, an excitation coil and the number of GMR sensors in the array sensor is optimized using numerical optimization based on the desirability approach. The main benefits of DSECT can be seen in terms of its modularity and flexibility for the use of different types of magnetic transducers/sensors, and signals of a different nature with either digital or analog outputs, making it suited for the ECT probe design using an array of GMR magnetic sensors. A real-time application of the DSECT distributed system for ECT inspection can be exploited for the inspection of 70 mm carbon steel pipe. In order to predict the axial and circumference defect detection, a mathematical model is developed based on the technique known as response surface methodology (RSM). The inspection results of a carbon steel pipe sample with artificial defects indicate that the system design is highly efficient. PMID:28335399

  11. An Eddy Current Testing Platform System for Pipe Defect Inspection Based on an Optimized Eddy Current Technique Probe Design.

    Science.gov (United States)

    Rifai, Damhuji; Abdalla, Ahmed N; Razali, Ramdan; Ali, Kharudin; Faraj, Moneer A

    2017-03-13

    The use of the eddy current technique (ECT) for the non-destructive testing of conducting materials has become increasingly important in the past few years. The use of the non-destructive ECT plays a key role in the ensuring the safety and integrity of the large industrial structures such as oil and gas pipelines. This paper introduce a novel ECT probe design integrated with the distributed ECT inspection system (DSECT) use for crack inspection on inner ferromagnetic pipes. The system consists of an array of giant magneto-resistive (GMR) sensors, a pneumatic system, a rotating magnetic field excitation source and a host PC acting as the data analysis center. Probe design parameters, namely probe diameter, an excitation coil and the number of GMR sensors in the array sensor is optimized using numerical optimization based on the desirability approach. The main benefits of DSECT can be seen in terms of its modularity and flexibility for the use of different types of magnetic transducers/sensors, and signals of a different nature with either digital or analog outputs, making it suited for the ECT probe design using an array of GMR magnetic sensors. A real-time application of the DSECT distributed system for ECT inspection can be exploited for the inspection of 70 mm carbon steel pipe. In order to predict the axial and circumference defect detection, a mathematical model is developed based on the technique known as response surface methodology (RSM). The inspection results of a carbon steel pipe sample with artificial defects indicate that the system design is highly efficient.

  12. An Eddy Current Testing Platform System for Pipe Defect Inspection Based on an Optimized Eddy Current Technique Probe Design

    Directory of Open Access Journals (Sweden)

    Damhuji Rifai

    2017-03-01

    Full Text Available The use of the eddy current technique (ECT for the non-destructive testing of conducting materials has become increasingly important in the past few years. The use of the non-destructive ECT plays a key role in the ensuring the safety and integrity of the large industrial structures such as oil and gas pipelines. This paper introduce a novel ECT probe design integrated with the distributed ECT inspection system (DSECT use for crack inspection on inner ferromagnetic pipes. The system consists of an array of giant magneto-resistive (GMR sensors, a pneumatic system, a rotating magnetic field excitation source and a host PC acting as the data analysis center. Probe design parameters, namely probe diameter, an excitation coil and the number of GMR sensors in the array sensor is optimized using numerical optimization based on the desirability approach. The main benefits of DSECT can be seen in terms of its modularity and flexibility for the use of different types of magnetic transducers/sensors, and signals of a different nature with either digital or analog outputs, making it suited for the ECT probe design using an array of GMR magnetic sensors. A real-time application of the DSECT distributed system for ECT inspection can be exploited for the inspection of 70 mm carbon steel pipe. In order to predict the axial and circumference defect detection, a mathematical model is developed based on the technique known as response surface methodology (RSM. The inspection results of a carbon steel pipe sample with artificial defects indicate that the system design is highly efficient.

  13. Power Management Based Current Control Technique for Photovoltaic-Battery Assisted Wind-Hydro Hybrid System

    Science.gov (United States)

    Ram Prabhakar, J.; Ragavan, K.

    2013-07-01

    This article proposes new power management based current control strategy for integrated wind-solar-hydro system equipped with battery storage mechanism. In this control technique, an indirect estimation of load current is done, through energy balance model, DC-link voltage control and droop control. This system features simpler energy management strategy and necessitates few power electronic converters, thereby minimizing the cost of the system. The generation-demand (G-D) management diagram is formulated based on the stochastic weather conditions and demand, which would likely moderate the gap between both. The features of management strategy deploying energy balance model include (1) regulating DC-link voltage within specified tolerances, (2) isolated operation without relying on external electric power transmission network, (3) indirect current control of hydro turbine driven induction generator and (4) seamless transition between grid-connected and off-grid operation modes. Furthermore, structuring of the hybrid system with appropriate selection of control variables enables power sharing among each energy conversion systems and battery storage mechanism. By addressing these intricacies, it is viable to regulate the frequency and voltage of the remote network at load end. The performance of the proposed composite scheme is demonstrated through time-domain simulation in MATLAB/Simulink environment.

  14. Nanorobotics current approaches and techniques

    CERN Document Server

    Ferreira, Antoine

    2013-01-01

    Nanorobot devices now perform a wide variety of tasks at the nanoscale in a wide variety of fields including but not limited to fields such as manufacturing, medicine, supply chain, biology, and outer space. Nanorobotics: Current Approaches and Techniques is a comprehensive overview of this interdisciplinary field with a wide ranging discussion that includes nano-manipulation and industrial nanorobotics, nanorobotics in biology and medicine, nanorobotic sensing, navigation and swarm behavior, and protein and DNA-based nanorobotics. Also included is the latest on topics such as bio-nano-actuators and propulsion and navigation of nanorobotic systems using magnetic fields. Nanorobotics: Current Approaches and Techniques is an ideal book for scientists, researchers, and engineers actively involved in applied and robotic research and development.

  15. Current status and prospects of nuclear physics research based on tracking techniques

    Science.gov (United States)

    Alekseev, V. A.; Alexandrov, A. B.; Bagulya, A. V.; Chernyavskiy, M. M.; Goncharova, L. A.; Gorbunov, S. A.; Kalinina, G. V.; Konovalova, N. S.; Okatyeva, N. M.; Pavlova, T. A.; Polukhina, N. G.; Shchedrina, T. V.; Starkov, N. I.; Tioukov, V. E.; Vladymirov, M. S.; Volkov, A. E.

    2017-01-01

    Results of nuclear physics research made using track detectors are briefly reviewed. Advantages and prospects of the track detection technique in particle physics, neutrino physics, astrophysics and other fields are discussed on the example of the results of the search for direct origination of tau neutrino in a muon neutrino beam within the framework of the international experiment OPERA (Oscillation Project with Emulsion-tRacking Apparatus) and works on search for superheavy nuclei in nature on base of their tracks in meteoritic olivine crystals. The spectra of superheavy elements in galactic cosmic rays are presented. Prospects of using the track detection technique in fundamental and applied research are reported.

  16. Plasma-based ambient mass spectrometry techniques: The current status and future prospective.

    Science.gov (United States)

    Ding, Xuelu; Duan, Yixiang

    2015-01-01

    Plasma-based ambient mass spectrometry is emerging as a frontier technology for direct analysis of sample that employs low-energy plasma as the ionization reagent. The versatile sources of ambient mass spectrometry (MS) can be classified according to the plasma formation approaches; namely, corona discharge, glow discharge, dielectric barrier discharge, and microwave-induced discharge. These techniques allow pretreatment-free detection of samples, ranging from biological materials (e.g., flies, bacteria, plants, tissues, peptides, metabolites, and lipids) to pharmaceuticals, food-stuffs, polymers, chemical warfare reagents, and daily-use chemicals. In most cases, plasma-based ambient MS performs well as a qualitative tool and as an analyzer for semi-quantitation. Herein, we provide an overview of the key concepts, mechanisms, and applications of plasma-based ambient MS techniques, and discuss the challenges and outlook.

  17. Breast reconstruction with anatomical implants: A review of indications and techniques based on current literature

    Directory of Open Access Journals (Sweden)

    Marco Gardani

    2017-09-01

    Full Text Available One important modality of breast cancer therapy is surgical treatment, which has become increasingly less mutilating over the last century. Breast reconstruction has become an integrated part of breast cancer treatment due to long-term psychosexual health factors and its importance for breast cancer survivors. Both autogenous tissue-based and implant-based reconstruction provides satisfactory reconstructive options due to better surgeon awareness of “the ideal breast size”, although each has its own advantages and disadvantages. An overview of the current options in breast reconstruction is presented in this article.

  18. Current Methods to Assess Human Cutaneous Blood Flow: An Updated Focus on Laser-Based-Techniques.

    Science.gov (United States)

    Cracowski, Jean-Luc; Roustit, Matthieu

    2016-07-01

    Several noninvasive techniques have been developed using laser light interaction in the skin to explore the skin's microcirculation. Combined with laser Doppler or LSCI, reactivity tests are used to explore skin endothelial and neurovascular function in humans, including PORH, LTH, PIV, and iontophoresis of vasodilators. Recent advances in our comprehension of the physiological pathways underlying these reactivity tests have been possible through topical or intradermal delivery of drugs that produce elevated local concentrations. Skin microvascular function has also been proposed as a prognostic biomarker or for evaluating the effect of drugs. Comprehension of the physiological pathways, together with recent technological improvements in microcirculation imaging, has provided reliable and reproducible tools to study skin microcirculation.

  19. Estimation of breast dose saving potential using a breast positioning technique for organ-based tube current modulated CT

    Science.gov (United States)

    Fu, Wanyi; Tian, Xiaoyu; Sturgeon, Gregory; Agasthya, Greeshma; Segars, William Paul; Goodsitt, Mitchell M.; Kazerooni, Ella A.; Samei, Ehsan

    2016-04-01

    In thoracic CT, organ-based tube current modulation (OTCM) reduces breast dose by lowering the tube current in the 120° anterior dose reduction zone of patients. However, in practice the breasts usually expand to an angle larger than the dose reduction zone. This work aims to simulate a breast positioning technique (BPT) to constrain the breast tissue to within the dose reduction zone for OTCM and to evaluate the corresponding potential reduction in breast dose. Thirteen female anthropomorphic computational phantoms were studied (age range: 27-65 y.o., weight range: 52-105.8 kg). Each phantom was modeled in the supine position with and without application of the BPT. Attenuation-based tube current (ATCM, reference mA) was generated by a ray-tracing program, taking into account the patient attenuation change in the longitudinal and angular plane (CAREDose4D, Siemens Healthcare). OTCM was generated by reducing the mA to 20% between +/- 60° anterior of the patient and increasing the mA in the remaining projections correspondingly (X-CARE, Siemens Healthcare) to maintain the mean tube current. Breast tissue dose was estimated using a validated Monte Carlo program for a commercial scanner (SOMATOM Definition Flash, Siemens Healthcare). Compared to standard tube current modulation, breast dose was significantly reduced using OTCM by 19.8+/-4.7%. With the BPT, breast dose was reduced by an additional 20.4+/-6.5% to 37.1+/-6.9%, using the same CTDIvol. BPT was more effective for phantoms simulating women with larger breasts with the average breast dose reduction of 30.2%, 39.2%, and 49.2% from OTCMBP to ATCM, using the same CTDIvol for phantoms with 0.5, 1.5, and 2.5 kg breasts, respectively. This study shows that a specially designed BPT improves the effectiveness of OTCM.

  20. [Tomodensitometry: current technique and perspectives].

    Science.gov (United States)

    Bousquet, J C

    1994-10-01

    The inventors of computed tomography were rewarded by the Nobel Prize for Medicine in 1979. This apparatus, now used routinely, is based on the physical principle of attenuation of x-rays combined with computerised calculation to generate a tomographic image of the human body. This article describes the components of computed tomography, the mode of acquisition, calculation and image reconstruction and the criteria of image quality and artefacts. Continuous rotation of the x-ray tube, now available on the latest machines, allows rapid 3D acquisition of raw data, largely eliminating movement artefacts, particularly those related to respiration. It is also possible to reconstitute images in a different plane from the plane of acquisition and to obtain 3D representations of the volume studied. The advantages and disadvantages of this recent technique are discussed.

  1. [Current techniques in tonsil surgery].

    Science.gov (United States)

    Coromina Isern, Jordi; Esteller Moré, Eduard

    2010-12-01

    In recent years, consolidation of tonsillar hypertrophy as the principal surgical procedure has led to the emergence of new techniques. Most aim to reduce volume (tonsillectomy or tonsil reduction). These techniques have considerably decreased intra- and postoperative hemorrhages and pain intensity. The present article describes the mechanisms and the advantages and disadvantages of the various techniques, including electro-dissection using electrical scalpels, reduction using a microdebrider, ultrasonic scalpel, radiofrequency (with its different variations) and CO(2) laser. When techniques that reduce tonsil volume are used, the possibility of recurrence of the tonsillar hypertrophy is high if less than 85% of the tonsil is removed. There is also a considerable possibility of infection of the remaining tonsils, whichever technique is used, and therefore these techniques are not valid in the case of repetitive tonsillitis. Recently, alternatives to classical adenoidectomy using adenoid curette have also appeared. Bleeding can be minimized by using a microdebrider, radiofrequency or a blood coagulator. We also discuss the concept of partial adenoidectomy, which is preferred in patients at risk of velopharyngeal insufficiency.

  2. Current techniques for visualizing RNA in cells

    Science.gov (United States)

    Mannack, Lilith V.J.C.; Eising, Sebastian; Rentmeister, Andrea

    2016-01-01

    Labeling RNA is of utmost interest, particularly in living cells, and thus RNA imaging is an emerging field. There are numerous methods relying on different concepts ranging from hybridization-based probes, over RNA-binding proteins to chemo-enzymatic modification of RNA. These methods have different benefits and limitations. This review aims to outline the current state-of-the-art techniques and point out their benefits and limitations. PMID:27158473

  3. Submucosal tunneling techniques: current perspectives

    Directory of Open Access Journals (Sweden)

    Kobara H

    2014-04-01

    Full Text Available Hideki Kobara,1 Hirohito Mori,1 Kazi Rafiq,2 Shintaro Fujihara,1 Noriko Nishiyama,1 Maki Ayaki,1 Tatsuo Yachida,1 Tae Matsunaga,1 Johji Tani,1 Hisaaki Miyoshi,1 Hirohito Yoneyama,1 Asahiro Morishita,1 Makoto Oryu,1 Hisakazu Iwama,3 Tsutomu Masaki1 1Department of Gastroenterology and Neurology, 2Department of Pharmacology, 3Life Science Research Center, Faculty of Medicine, Kagawa University, Miki-cho, Kita-Gun, Kagawa, Japan Abstract: Advances in endoscopic submucosal dissection include a submucosal tunneling technique, involving the introduction of tunnels into the submucosa. These tunnels permit safer offset entry into the peritoneal cavity for natural orifice transluminal endoscopic surgery. Technical advantages include the visual identification of the layers of the gut, blood vessels, and subepithelial tumors. The creation of a mucosal flap that minimizes air and fluid leakage into the extraluminal cavity can enhance the safety and efficacy of surgery. This submucosal tunneling technique was adapted for esophageal myotomy, culminating in its application to patients with achalasia. This method, known as per oral endoscopic myotomy, has opened up the new discipline of submucosal endoscopic surgery. Other clinical applications of the submucosal tunneling technique include its use in the removal of gastrointestinal subepithelial tumors and endomicroscopy for the diagnosis of functional and motility disorders. This review suggests that the submucosal tunneling technique, involving a mucosal safety flap, can have potential values for future endoscopic developments. Keywords: submucosal endoscopy, submucosal tunneling method, natural orifice transluminal endoscopic surgery, peroral endoscopic myotomy, gastrointestinal subepithelial tumor, functional and motility disorders

  4. A new technique based on current measurement for nanoscale ferroelectricity assessment: Nano-positive up negative down

    Science.gov (United States)

    Martin, Simon; Baboux, Nicolas; Albertini, David; Gautier, Brice

    2017-02-01

    In this paper, we propose a new procedure which aims at measuring the polarisation switching current at the nanoscale on ferroelectric thin films with the atomic force microscope tip used as a top electrode. Our technique is an adaptation of the so-called positive up negative down method commonly operated on large electrodes. The main obstacle that must be overcome to implement such measurement is the enhancement of the signal to noise ratio, in a context where the stray capacitance of the sample/tip/lever/lever holder system generates a dielectric displacement current several orders of magnitude higher than the current to be measured. This problem is solved by the subtraction of the displacement current through a reference capacitance. For the first time, we show an example of nanoscale positive up negative down measurement of the polarisation charge on a PbZrTiO3 thin film and compare the measured value with paraelectric samples. From the comparison with macroscopic measurement, we deduce the effective area of contact between the tip and the sample.

  5. A new technique for measuring the leakage current in Silicon Drift Detector based X-ray spectrometer—implications for on-board calibration

    Science.gov (United States)

    Shanmugam, M.; Acharya, Y. B.; Vadawale, S. V.; Mazumdar, H. S.

    2015-02-01

    In this work, we report a new technique of measuring the leakage current in Silicon Drift Detectors (SDD) and propose to use this technique as a tool for on-board estimation of the radiation damage to the SDD employed in space-borne X-ray spectrometers. The leakage current of a silicon based detector varies with the detector operating temperature and increases with the radiation dose encountered by the detector in the space environment. The proposed technique to measure detector leakage current involves measurement of the reset frequency of the reset type charge sensitive pre-amplifier when the feedback capacitor is charged only due to the detector leakage current. Using this technique, the leakage current is measured for large samples of SDDs having two different active areas of 40 mm2 and 109 mm2 with 450 micron thick silicon. These measurements are carried out in the temperature range of -50°C to 20°C. At each step energy resolution is measured for all SDDs using Fe-55 X-ray source and shown that the energy resolution varies systematically with the leakage current irrespective of the difference among the detectors of the same as well as different sizes. Thus by measuring the leakage current on-board, it would be possible to estimate the time dependent performance degradation of the SDD based X-ray spectrometer. This can be particularly useful in case where large numbers of SDD are used.

  6. Superresolution imaging: a survey of current techniques

    Science.gov (United States)

    Cristóbal, G.; Gil, E.; Šroubek, F.; Flusser, J.; Miravet, C.; Rodríguez, F. B.

    2008-08-01

    Imaging plays a key role in many diverse areas of application, such as astronomy, remote sensing, microscopy, and tomography. Owing to imperfections of measuring devices (e.g., optical degradations, limited size of sensors) and instability of the observed scene (e.g., object motion, media turbulence), acquired images can be indistinct, noisy, and may exhibit insuffcient spatial and temporal resolution. In particular, several external effects blur images. Techniques for recovering the original image include blind deconvolution (to remove blur) and superresolution (SR). The stability of these methods depends on having more than one image of the same frame. Differences between images are necessary to provide new information, but they can be almost unperceivable. State-of-the-art SR techniques achieve remarkable results in resolution enhancement by estimating the subpixel shifts between images, but they lack any apparatus for calculating the blurs. In this paper, after introducing a review of current SR techniques we describe two recently developed SR methods by the authors. First, we introduce a variational method that minimizes a regularized energy function with respect to the high resolution image and blurs. In this way we establish a unifying way to simultaneously estimate the blurs and the high resolution image. By estimating blurs we automatically estimate shifts with subpixel accuracy, which is inherent for good SR performance. Second, an innovative learning-based algorithm using a neural architecture for SR is described. Comparative experiments on real data illustrate the robustness and utilization of both methods.

  7. Non-contact online thickness measurement system for metal films based on eddy current sensing with distance tracking technique.

    Science.gov (United States)

    Li, Wei; Wang, Hongbo; Feng, Zhihua

    2016-04-01

    This paper proposes an online, non-contact metal film thickness measurement system based on eddy current sensing. The slope of the lift-off curve (LOC) is used for characterizing target thickness. Theoretical derivation was conducted to prove that the slope is independent of the lift-off variation. In practice, the measurement has some immunity to the lift-off, but not perfect. The slope of LOC is still affected at some extent by the lift-off. Hence, a height tracking system was also proposed, which could stabilize the distance between the sensor and the target and significantly reduce the lift-off effect. The height tracking system contains a specially designed probe, which could vibrate rapidly to obtain a fast measurement speed, and its height can be adjusted up and down continuously to stabilize the lift-off. The sensor coil in the thickness measurement system was also used as the height sensor in the height tracking system. Several experiments were conducted to test the system performances under static and dynamic conditions. This measurement system demonstrated significant advantages, such as simple and clear conversion between the slope of LOC and target thickness, high resolution and stability, and minimized effect of lift-off variation.

  8. Gastrointestinal tract imaging in children: current techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hiorns, Melanie P. [Great Ormond Street Hospital for Children, Radiology Department, London (United Kingdom)

    2011-01-15

    Imaging of the gastrointestinal (GI) tract in children continues to evolve, with new techniques, both radiological and non-radiological, being added to the repertoire. This article provides a summary of current imaging techniques of the GI tract (primarily the upper GI tract) and the relationship between those techniques. It covers the upper GI series and other contrast studies, US, CT and MRI. Note is also made of the contribution now made by capsule endoscopy (CE). Abdominal emergency imaging is not covered in this article. (orig.)

  9. Current and emerging techniques in gastrointestinal imaging

    Directory of Open Access Journals (Sweden)

    McSweeney S

    2010-01-01

    Full Text Available This review is devoted to current and emerging techniques in gastrointestinal (GI imaging. It is divided into three sections focusing on areas that are both interesting and challenging: imaging of the small bowel and appendix, imaging of the colon and rectum and finally liver and pancreas in the upper abdomen. The first section covers cross-sectional imaging of the small bowel using the techniques of multidetector computed tomography (MDCT (including CT enterography and magnetic resonance imaging (MRI. The evaluation of mesenteric ischemia and GI tract bleeding using MDCT angiography is also reviewed. Current imaging practice in the evaluation of appendix is also reviewed and illustrated. The second section reviews CT and MR colonography and imaging of the rectum. It describes CT virtual colonoscopy (CTVC with emphasis on the advantages and disadvantages of the technique with discussion of the role of CTVC in screening. The intriguing topic of MR colonography (MRC is also reviewed. Imaging of the rectum with emphasis on imaging of rectal cancer is described with the roles of CT, MR, endoluminal ultrasound and positron emission tomography scanning discussed. The final section reviews current and emerging techniques in liver imaging with the role of ultrasound including contrast ultrasound, MDCT and MR (including contrast agents discussed. The new developments and applications of imaging of pancreatic disease are discussed with emphasis on the role of MDCT and MRI with gadolinium. This review highlights the current role and advancement of imaging techniques with new diagnostic and prognostic information pertinent to gastrointestinal disease continuing to emerge.

  10. Filtering Spam: Current Trends and Techniques

    Directory of Open Access Journals (Sweden)

    Geerthik S.

    2013-07-01

    Full Text Available This article gives an overview about latest trend and techniques in spam filtering. We analyzed the problems which is introduced by spam ,what spam actually do and how to measure the spam .This article mainly focuses on automated, non-interactive filters, with a broad review ranging from commercial implementations to ideas confined to current research papers. The solutions using both machine and non –machine learning approaches are reviewed and taxonomy of different approaches is presented. While a range of different techniques have and continue to be evaluated in academic research, heuristic and Bayesian filtering, along with its variants provide the greatest potential for future spam prevention.

  11. Robotic partial nephrectomy: current technique and outcomes.

    Science.gov (United States)

    Wang, Liang; Lee, Benjamin R

    2013-09-01

    Over the past decade, management of the T1 renal mass has focused on nephron-sparing surgery. Robotic partial nephrectomy has played an increasing role in the technique of preserving renal function by decreasing warm ischemia time, as well as optimizing outcomes of hemorrhage and fistula. Robot-assisted partial nephrectomy is designed to provide a minimally-invasive nephron-sparing surgical option utilizing reconstructive capability, decreasing intracorporeal suturing time, technical feasibility and safety. Ultimately, its benefits are resulting in its dissemination across institutions. Articulated instrumentation and three-dimensional vision facilitate resection, collecting system reconstruction and renorrhaphy, leading to decreased warm ischemia time while preserving oncological outcomes. The aim of the present review was to present our surgical sequence and technique, as well as review the current status of robot-assisted partial nephrectomy.

  12. Technical Note: Phantom study to evaluate the dose and image quality effects of a computed tomography organ-based tube current modulation technique

    Energy Technology Data Exchange (ETDEWEB)

    Gandhi, Diksha; Schmidt, Taly Gilat, E-mail: taly.gilat-schmidt@marquette.edu [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53201 (United States); Crotty, Dominic J.; Stevens, Grant M. [GE Healthcare, Waukesha, Wisconsin 53188 (United States)

    2015-11-15

    Purpose: This technical note quantifies the dose and image quality performance of a clinically available organ-dose-based tube current modulation (ODM) technique, using experimental and simulation phantom studies. The investigated ODM implementation reduces the tube current for the anterior source positions, without increasing current for posterior positions, although such an approach was also evaluated for comparison. Methods: Axial CT scans at 120 kV were performed on head and chest phantoms on an ODM-equipped scanner (Optima CT660, GE Healthcare, Chalfont St. Giles, England). Dosimeters quantified dose to breast, lung, heart, spine, eye lens, and brain regions for ODM and 3D-modulation (SmartmA) settings. Monte Carlo simulations, validated with experimental data, were performed on 28 voxelized head phantoms and 10 chest phantoms to quantify organ dose and noise standard deviation. The dose and noise effects of increasing the posterior tube current were also investigated. Results: ODM reduced the dose for all experimental dosimeters with respect to SmartmA, with average dose reductions across dosimeters of 31% (breast), 21% (lung), 24% (heart), 6% (spine), 19% (eye lens), and 11% (brain), with similar results for the simulation validation study. In the phantom library study, the average dose reduction across all phantoms was 34% (breast), 20% (lung), 8% (spine), 20% (eye lens), and 8% (brain). ODM increased the noise standard deviation in reconstructed images by 6%–20%, with generally greater noise increases in anterior regions. Increasing the posterior tube current provided similar dose reduction as ODM for breast and eye lens, increased dose to the spine, with noise effects ranging from 2% noise reduction to 16% noise increase. At noise equal to SmartmA, ODM increased the estimated effective dose by 4% and 8% for chest and head scans, respectively. Increasing the posterior tube current further increased the effective dose by 15% (chest) and 18% (head

  13. Current research projects on traffic conflicts technique studies.

    NARCIS (Netherlands)

    Hondel, M. van den & and Kraay, J.H.

    1979-01-01

    A review of current research concerning the development, evaluation and use of the traffic conflicts technique is presented. The 32 studies, selected from the IRRD data base, are listed alphabetically by names of countries and under countries by names of research organizations. The IRRD descriptions

  14. Alternating Current Heating Technique of Hollow Rod

    Institute of Scientific and Technical Information of China (English)

    Na Weisheng; Shi Tonghao

    1995-01-01

    @@ In recent years, wellbore heat tracing technique is widely used in development of high viscosity and high pour point crude oil. Theory and experiences show that wellbore heat tracing has obvious effect on increasing liquid yield of oil wells.

  15. Novel current monitoring techniques without shunt resistors

    Directory of Open Access Journals (Sweden)

    VODA Adriana

    2012-05-01

    Full Text Available Current measurement for automotiveelectrical actuator applications (with motors or valvesis necessary for appropriate control in many cases anda safety requirement in all cases: the control algorithmmay be dependent on the data but safety relevantfunctions will use it to determine possible over-current,over-temperature or failure conditions. This paperproposes an alternative method of monitoring thecurrent, without using sensors or current shunts.Instead, measurements are made on the motor in thedevelopment stages and low/high frequency variationsin the supply line are monitored, through low/highpassfilters, by available AD channels in the system.This results in cost reduction for the final product, byreducing hardware complexity.

  16. [Our current technique for basic pterional craniotomy].

    Science.gov (United States)

    Kaneko, Nobuyuki; Kurita, Hiroki; Hino, Ken; Nagayama, Kazuki; Tsubokawa, Tamiji; Tanaka, Naoko; Fujitsuka, Mitsuyuki; Nakamura, Masanao; Shiokawa, Yoshiaki

    2005-09-01

    Pterional cnaniotomy is frequently used in neurosurgical practice, but still poses significant cosmetic and functional drawbacks. Here, we describe our modified technique to overcome such problems as the sterilization of the scalp without brush and razor, preemptive analgesia, preservation of the periostium for reconstruction, retrograde dissection of the temporal muscle, and complete sphenoidotomy using chisel or drills. The tips of our pterional craniotomy offer suitable size and depth of working field around the paraclinoidal regions, maintaining cosmetic satisfaction of the patients.

  17. A Novel Technique for Maximum Power Point Tracking of a Photovoltaic Based on Sensing of Array Current Using Adaptive Neuro-Fuzzy Inference System (ANFIS)

    Science.gov (United States)

    El-Zoghby, Helmy M.; Bendary, Ahmed F.

    2016-10-01

    Maximum Power Point Tracking (MPPT) is now widely used method in increasing the photovoltaic (PV) efficiency. The conventional MPPT methods have many problems concerning the accuracy, flexibility and efficiency. The MPP depends on the PV temperature and solar irradiation that randomly varied. In this paper an artificial intelligence based controller is presented through implementing of an Adaptive Neuro-Fuzzy Inference System (ANFIS) to obtain maximum power from PV. The ANFIS inputs are the temperature and cell current, and the output is optimal voltage at maximum power. During operation the trained ANFIS senses the PV current using suitable sensor and also senses the temperature to determine the optimal operating voltage that corresponds to the current at MPP. This voltage is used to control the boost converter duty cycle. The MATLAB simulation results shows the effectiveness of the ANFIS with sensing the PV current in obtaining the MPPT from the PV.

  18. Pediatric imaging: Current and emerging techniques

    Directory of Open Access Journals (Sweden)

    Shenoy-Bhangle A

    2010-01-01

    Full Text Available Imaging has always been an important component of the clinical evaluation of pediatric patients. Rapid technological advances in imaging are making noninvasive evaluation of a wide range of pediatric diseases possible. Ultrasound and magnetic resonance imaging (MRI are two imaging modalities that do not involve ionizing radiation and are preferred imaging modalities in the pediatric population. Computed tomography (CT remains the imaging modality with the highest increase in utilization in children due to its widespread availability and rapid image acquisition. Emerging imaging applications to be discussed include MR urography, voiding urosonography with use of ultrasound contrast agents, CT dose reduction techniques, MR enterography for inflammatory bowel disease, and MR cine airway imaging.

  19. Flow tracing based on current

    Institute of Scientific and Technical Information of China (English)

    蔡兴国; 曹海龙

    2001-01-01

    Analyses the flow tracing based on power flow, points out that the detachment of reactive power and active power is unrealiable and concludes that the current is the real basic of flow tracing,and proposes the new flow tracing model based on current, which devides the current into active current and reactive current, analyses the theory about the matrix to deal with the precision and realization of the flow tracing, and then proposes a new pricing model by fixed rate and marginal rate, which keeps not only economy information such as congestion cost in marginal cost based pricing, but also benefits to make both ends meet.

  20. Nondestructive examination of PHWR pressure tube using eddy current technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Jong; Choi, Sung Nam; Cho, Chan Hee; Yoo, Hyun Joo; Moon, Gyoon Young [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2014-06-15

    A pressurized heavy water reactor (PHWR) core has 380 fuel channels contained and supported by a horizontal cylindrical vessel known as the calandria, whereas a pressurized water reactor (PWR) has only a single reactor vessel. The pressure tube, which is a pressure-retaining component, has a 103.4 mm inside diameter x 4.19 mm wall thickness, and is 6.36 m long, made of a zirconium alloy (Zr-2.5 wt% Nb). This provides support for the fuel while transporting the D2O heat-transfer fluid. The simple tubular geometry invites highly automated inspection, and good approach for all inspection. Similar to all nuclear heat-transfer pressure boundaries, the PHWR pressure tube requires a rigorous, periodic inspection to assess the reactor integrity in accordance with the Korea Nuclear Safety Committee law. Volumetric-based nondestructive evaluation (NDE) techniques utilizing ultrasonic and eddy current testing have been adopted for use in the periodic inspection of the fuel channel. The eddy current testing, as a supplemental NDE method to ultrasonic testing, is used to confirm the flaws primarily detected through ultrasonic testing, however, eddy current testing offers a significant advantage in that its ability to detect surface flaws is superior to that of ultrasonic testing. In this paper, effectiveness of flaw detection and the depth sizing capability by eddy current testing for the inside surface of a pressure tube, will be introduced. As a result of this examination, the ET technique is found to be useful only as a detection technique for defects because it can detect fine defects on the surface with high resolution. However, the ET technique is not recommended for use as a depth sizing method because it has a large degree of error for depth sizing.

  1. High-accuracy current sensing circuit with current compensation technique for buck-boost converter

    Science.gov (United States)

    Rao, Yuan; Deng, Wan-Ling; Huang, Jun-Kai

    2015-03-01

    A novel on-chip current sensing circuit with current compensation technique suitable for buck-boost converter is presented in this article. The proposed technique can sense the full-range inductor current with high accuracy and high speed. It is mainly based on matched current mirror and does not require a large proportion of aspect ratio between the powerFET and the senseFET, thus it reduces the complexity of circuit design and the layout mismatch issue without decreasing the power efficiency. The circuit is fabricated with TSMC 0.25 µm 2P5M mixed-signal process. Simulation results show that the buck-boost converter can be operated at 200 kHz to 4 MHz switching frequency with an input voltage from 2.8 to 4.7 V. The output voltage is 3.6 V, and the maximum accuracy for both high and low side sensing current reaches 99% within the load current ranging from 200 to 600 mA.

  2. J-R Curve Determination for Disk-shaped Compact Specimens Based on the Normalization Method and Direct Current Potential Drop Technique

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiang [ORNL; Nanstad, Randy K [ORNL; Sokolov, Mikhail A [ORNL

    2014-01-01

    Material ductile fracture toughness can be described by J-integral versus crack extension relationship (J-R curve). As a conventional J-R curve measurement method, unloading compliance (UC) becomes impractical in elevated temperature testing due to relaxation of the material and a friction induced back-up shape of the J-R curve. In addition, the UC method may underpredict the crack extension for standard disk-shaped compact (DC(T)) specimens. In order to address these issues, the normalization method and direct current potential drop (DCPD) technique were applied for determining J-R curves at 24 C and 500 C for 0.18T DC(T) specimens made from type 316L stainless steel. For comparison purchase, the UC method was also applied in 24 C tests. The normalization method was able to yield valid J-R curves in all tests. The J-R curves from the DCPD technique need adjustment to account for the potential drop induced by plastic deformation, crack blunting, etc. and after applying a newly-developed DCPD adjustment procedure, the post-adjusted DCPD J-R curves essentially matched J-R curves from the normalization method. In contrast, the UC method underpredicted the crack extension in all tests resulting in substantial deviation in the derived J-R curves manifested by high Jq values than the normalization or DCPD method. Only for tests where the UC method underpredicted the crack extension by a very small value, J-R curves determined by the UC method were similar to those determined by the normalization or DCPD method.

  3. Nontraditional manufacturing technique-Nano machining technique based on SPM

    Institute of Scientific and Technical Information of China (English)

    DONG; Shen; YAN; Yongda; SUN; Tao; LIANG; Yingchun; CHENG

    2004-01-01

    Nano machining based on SPM is a novel, nontraditional advanced manufacturing technique. There are three main machining methods based on SPM, i.e.single atom manipulation, surface modification using physical or chemical actions and mechanical scratching. The current development of this technique is summarized. Based on the analysis of mechanical scratching mechanism, a 5 μm micro inflation hole is fabricated on the surface of inertial confinement fusion (ICF) target. The processing technique is optimized. The machining properties of brittle material, single crystal Ge, are investigated. A micro machining system combining SPM and a high accuracy stage is developed. Some 2D and 3D microstructures are fabricated using the system. This method has broad applications in the field of nano machining.

  4. Ferromagnetic Tubes Testing Based Pulsed Remote Field Eddy Current Technique%基于脉冲远场涡流的管道内检测技术

    Institute of Scientific and Technical Information of China (English)

    杨理践; 王赓; 高松巍

    2012-01-01

    针对传统远场涡流检测方法对铁磁性管道内外壁缺陷灵敏度相同,无法有效区分缺陷在管道内壁还是管道外表面的问题,提出了采用具有丰富频率成分的脉冲激励信号取代传统的远场涡流中正弦信号激励的方法.采用小波去噪方法滤除检测数据中的信号噪声;研究了将检测线圈分别置于近场区、过渡区和远场区时的信号时域特性与管壁伤的关系;进行了针对管道管壁内外相同宽度不同深度缺陷的检测试验,结果表明采用脉冲激励作为激励源并综合运用过渡区的检测信号的幅值和过零时间特征能够有效地区分管壁内外全周向的缺陷.%In view of the traditional remote field eddy current technique for ferromagnetic tube having the same sensitivity of inner and outside walls defect,unable to distinguish the defects in the inner wall or in the outer surface,this paper adopt with abundant frequency components of the pulse signal to replace the traditional remote field eddy current sinusoidal excitation signal. Using the methods of wavelet denoising to filter acquired signal and process the data. This paper studied the relationship between the tube wall defects and signal time-domain characteristics when the detector coil was placed in the direct zone, transition zone and remote field zone. Conduct experiments to acquire data about different depth defects in the inside or outside of the walls, the results show that using the pulse signal as excitation source and characteristics about the detect signal amplitude and zero-crossing time can effectively distinguish between the inner and outer circumferential direction tube wall defects.

  5. Simple Augmented Current Controller with OHC Technique for grid current compensation in the Distribution System

    Directory of Open Access Journals (Sweden)

    S. Rajalingam

    2014-05-01

    Full Text Available This paper presents a novel control technique on four leg inverter with which the distribution grid is interconnected with the domestic houses. Most of the houses in the distribution side possess inverter for the usage of Electricity. With the advancement in Solar & wind, it will become easy to see houses, often with solar & a small Wind power system. The excess power generated can be exchanged with the Electricity Board for providing uninterruptible power supply. During this exchange there may be a deterioration in the quality of power, most often the grid current gets affected with a large harmonic distortion, and also there exists unbalanced grid currents. Thus, it is necessary to provide uninterruptible power supply with good quality of power. In spite of several controllers, the proposed augmented controller has its own reliability & quick response with Overall Harmonic Compensation (OHC technique which relies on DSP based filter. This Augmented based control technique with OHC is demonstrated extensively with MATLAB/Simulink simulation.

  6. A New PWM Modifying Technique for Reconstructing Three-phase Currents from DC Bus Current

    Science.gov (United States)

    Aoyagi, Shigehisa; Iwaji, Yoshitaka; Tobari, Kazuaki; Sakamoto, Kiyoshi

    Vector control is used to drive a DC brushless motor and generally needs current information. DC bus current detection is often adopted as a low cost method for reconstructing three-phase currents. PWM modifying techniques increase the DC pulse duration, thereby enabling easy detection of the DC bus current. However, these techniques have two problems: reducing a noise frequency and making the reconstructed current waveforms distorted by current ripple. In the techniques, modification signals are added to the three-phase voltage commands; the sum of the signals over a single cycle is zero. The authors examined several PWM modifying techniques from the points of view of noise and current distortion performance. One of the techniques had a good noise performance, and the frequency component of the noise was the same as the carrier frequency (fc). However, the reconstructed current waveforms were distorted. The total harmonic distortion (THD) varied from 1.7% to 4.1%. Another technique had a very poor noise performance, and the frequency component on the noise was one-fourth of fc. The authors developed a new PWM modifying method called “Half Pulse Shift”, which achieves the optimum noise and current distortion performance. The frequency component of the new method was two-thirds of fc, and the current waveforms were not distorted; the THD in the simulations and experiments was 0.5%-1.4% and 3.4%-3.6%, respectively.

  7. Squid based beam current meter

    Energy Technology Data Exchange (ETDEWEB)

    Kuchnir, M.

    1983-11-25

    A SQUID based beam current meter has the capability of measuring the current of a beam with as little as 30 x 155 antiprotons (with a signal to noise ratio of 2). If low noise dc current is used to cancel most of the beam or an up-down counter is used to count auto-resets this sensitivity will be available at any time in the acumulation process. This current meter will therefore be a unique diagnostic tool for optimizing the performance of several Tev I components. Besides requiring liquid helium it seems that its only drawback is not to follow with the above sensitivity a sudden beam change larger than 16 ..mu..A, something that could be done using a second one in a less sensitive configuration.

  8. Current source and digital demodulation technique in EIT system based on FPGA%一种基于FPGA的EIT电流源和数字解调方法

    Institute of Scientific and Technical Information of China (English)

    郝会玲; 赵德春; 沙洪

    2012-01-01

    Objective A general experiment platform of electrical impedance tomography(EIT) based on field programmable gate array(FPGA) was designed to meet the requirements of EIT digital measurement.A digital current source and the research on digital demodulation method was completed.Methods For construction of the experiment platform,DDS module,D/A and A/D interface module,digital demodulation module and RS-232 communication module were all integrated in one FPGA chip.Results The source can provide multi-frequency excitation signals of 2 mA in the range of 6.1-390.6 kHz.The output impedance of the source was higher than 190 kΩ.Both the real and the virtual information of measured impedance could be extracted.Conclusion Measurements based on bioimpedance-equivalent circuit model verified the validity of the platform.The research results of this paper provides a foundation for the construction of a practical EIT system.%目的 依据数字化电阻抗断层成像(EIT)硬件系统的要求,构建了基于现场可编程门阵列(FPGA)的通用型EIT硬件实验平台,完成了直接数字频率合成(DDS)的电流源和数字解调方法研究.方法 实验平台以FPGA芯片为核心,集成了DDS模块、D/A及A/D接口模块、数字解调模块和RS-232数据通信等模块.结果 电流源可在6.1~390.6 kHz范围输出多频激励信号,输出阻抗大于190 kΩ,电流峰峰值为2 mA.数字解调模块可同时提取被测阻抗的实部和虚部信息.结论 采用生物组织等效模型进行的模拟测试验证了本研究系统工作的有效性,为实用化EIT系统的建立奠定了基础.

  9. The Current Status of Peer Assessment Techniques and Sociometric Methods.

    Science.gov (United States)

    Bukowski, William M; Castellanos, Melisa; Persram, Ryan J

    2017-09-01

    Current issues in the use of peer assessment techniques and sociometric methods are discussed. Attention is paid to the contributions of the four articles in this volume. Together these contributions point to the continual level of change and progress in these techniques. They also show that the paradigm underlying these methods has been unchanged for decades. It is argued that this domain is ripe for a paradigm change that takes advantage of recent developments in statistical techniques and technology. © 2017 Wiley Periodicals, Inc.

  10. Detection of localized damage by eddy currents technique

    Directory of Open Access Journals (Sweden)

    Aoukili A.

    2014-01-01

    Full Text Available Non destructive evaluation techniques based on eddy currents (EC are largely used for quality control of the castings in a lot of industries. The principle of detection by EC consists in using an adequate inductive coil to generate them by a variable magnetic field, and measuring their effects by using one or several sensors. These effects result from the interaction between the induced magnetic field and the excited conductive material. A local variation of the physical properties or geometry of the tested sample, due to a singularity or a flaw, causes a modification of the EC distribution, enabling thus detection. In order to optimize the capacity of defect revealing by means of EC based probes, an accurate modelling of the problem is essential. This can be used to perform simulation of the EC distribution under different circumstances and to analyze the EC sensitivity to the various implicated parameters. In this work, the modelling of EC is made by using the finite element method. Using a B-scan strategy was used, detection of a small defect having the shape of an open cavity is shown to be correctly indicated via monitoring variations of the induced voltage in the receiver coil.

  11. In-Plane Thermal Diffusivity Measurement of Thin Films Based on the Alternating-Current Calorimetric Method Using an Optical Reflectivity Technique

    Institute of Scientific and Technical Information of China (English)

    黄正兴; 唐祯安; 许自强; 丁海涛; 顾毓沁

    2004-01-01

    An advanced ac calorimetric method to measure thermal diffusivity of a thin sample is developed by using an optical reflectivity technique. A modulated infrared laser is used to heat the front surface ofa foil specimen. The reflectivity of a continuous-wave He-Ne laser at the rear surface of the specimen is detected by a photoreceiver.According to the temperature dependence of reflectivity, the ac temperature response is obtained. Thermal diffusivity is deduced from a one-dimensional heat conduction equation. A stainless-steel foil and a copper foil are chosen as the samples. The present results agree well with the data in the literature.

  12. High-resolution three-dimensional imaging of a depleted CMOS sensor using an edge Transient Current Technique based on the Two Photon Absorption process (TPA-eTCT)

    CERN Document Server

    García, Marcos Fernández; Echeverría, Richard Jaramillo; Moll, Michael; Santos, Raúl Montero; Moya, David; Pinto, Rogelio Palomo; Vila, Iván

    2016-01-01

    For the first time, the deep n-well (DNW) depletion space of a High Voltage CMOS sensor has been characterized using a Transient Current Technique based on the simultaneous absorption of two photons. This novel approach has allowed to resolve the DNW implant boundaries and therefore to accurately determine the real depleted volume and the effective doping concentration of the substrate. The unprecedented spatial resolution of this new method comes from the fact that measurable free carrier generation in two photon mode only occurs in a micrometric scale voxel around the focus of the beam. Real three-dimensional spatial resolution is achieved by scanning the beam focus within the sample.

  13. Current techniques for assessing developmental neurotoxicity of pesticides

    Institute of Scientific and Technical Information of China (English)

    Yu GAO; Ying TIAN; Xiaoming SHEN

    2008-01-01

    Organophosphates (OPs) and Pyrethroids (PRY) have been widely used in agriculture and in the home as broad spectrum insecticides, but may produce considerable risk to human health, especially to children. Children are more susceptible to environmental exposure, and concern about the neurotoxic effects of pesticide exposure on children is increasing. There is a need for better understanding of the potential developmental neu-rotoxicity of pesticides. Techniques for assessing devel-opmental neurotoxicity of pesticides will continue to be developed, rendering a need for flexibility of testing para-digms. Current techniques used in evaluating the devel-opmental neurotoxicity of OPs and PRY are presented in this review. These include: (1) In vitro techniques (PC12 cells, C6 cells and other cell models); (2) Non-mammalian models (sea urchins, zebrafish and other non-mammalian models); and (3) In vivo mammalian models (morpho-logical techniques, neurobehavioral assessments and biomarkers).

  14. Biopsy of parotid masses:Review of current techniques

    Institute of Scientific and Technical Information of China (English)

    Sananda Haldar; Joseph D Sinnott; Kemal M Tekeli; Samuel S Turner; David C Howlett

    2016-01-01

    Definitive diagnosis of parotid gland masses is required optimal management planning and for prognosis. There is controversy over whether fine needle aspiration cytology(FNAC) or ultrasound guided core biopsy(USCB) should be the standard for obtaining a biopsy. The aim of this review is to assess the current evidence available to assess the benefits of each technique and also to assess the use of intra-operative frozen section(IOFS). Literature searches were performed using pubmed and google scholar. The literature has been reviewed and the evidence is presented. FNAC is an accepted and widely used technique. It has been shown to have variable diagnostic capabilities depending on centres and experience of staff. USCB has a highly consistent diagnostic accuracy and can help with tumour grading and staging. However, the technique is more invasive and there is a question regarding potential for seeding. Furthermore, USCB is less likely to be offered as part of a one-stop clinic. IOFS has no role as a first line diagnostic technique but may be reserved as an adjunct or for lesions not amenable to percutaneous biopsy. On balance, USCB seems to be the method of choice. The current evidence suggests it has superior diagnostic potential and is safe. With time, USCB is likely to supplant FNAC as the biopsy technique of choice, replicating that which has occurred already in other areas of medicine such a breast practice.

  15. Image analysis technique applied to lock-exchange gravity currents

    OpenAIRE

    Nogueira, Helena; Adduce, Claudia; Alves, Elsa; Franca, Rodrigues Pereira Da; Jorge, Mario

    2013-01-01

    An image analysis technique is used to estimate the two-dimensional instantaneous density field of unsteady gravity currents produced by full-depth lock-release of saline water. An experiment reproducing a gravity current was performed in a 3.0 m long, 0.20 m wide and 0.30 m deep Perspex flume with horizontal smooth bed and recorded with a 25 Hz CCD video camera under controlled light conditions. Using dye concentration as a tracer, a calibration procedure was established for each pixel in th...

  16. Defect detection in conducting materials using eddy current testing techniques

    Directory of Open Access Journals (Sweden)

    Brauer Hartmut

    2014-01-01

    Full Text Available Lorentz force eddy current testing (LET is a novel nondestructive testing technique which can be applied preferably to the identification of internal defects in nonmagnetic moving conductors. The LET is compared (similar testing conditions with the classical eddy current testing (ECT. Numerical FEM simulations have been performed to analyze the measurements as well as the identification of internal defects in nonmagnetic conductors. The results are compared with measurements to test the feasibility of defect identification. Finally, the use of LET measurements to estimate of the electrical conductors under test are described as well.

  17. Radiotherapy in prostate cancer. Innovative techniques and current controversies

    Energy Technology Data Exchange (ETDEWEB)

    Geinitz, Hans [Krankenhaus der Barmherzigen Schwestern, Linz (Austria). Dept. of Radiation Oncology; Linz Univ. (Austria). Medical Faculty; Roach, Mack III [California Univ., San Francisco, CA (United States). Dept. of Radiation Oncology; Van As, Nicholas (ed.) [The Institute of Cancer Research, Sutton Surrey (United Kingdom)

    2015-04-01

    Examines in detail the role of innovative radiation techniques in the management of prostate cancer, including IMRT, IGRT, BART, and modern brachytherapy. Explores a range of current controversies in patient treatment. Intended for both radiation oncologists and urologists. Radiation treatment is rapidly evolving owing to the coordinated research of physicists, engineers, computer and imaging specialists, and physicians. Today, the arsenal of ''high-precision'' or ''targeted'' radiotherapy includes multimodal imaging, in vivo dosimetry, Monte Carlo techniques for dose planning, patient immobilization techniques, intensity-modulated radiotherapy (IMRT), image-guided radiotherapy (IGRT), biologically adapted radiotherapy (BART), quality assurance methods, novel methods of brachytherapy, and, at the far end of the scale, particle beam radiotherapy using protons and carbon ions. These approaches are like pieces of a puzzle that need to be put together to provide the prostate cancer patient with high-level optimized radiation treatment. This book examines in detail the role of the above-mentioned innovative radiation techniques in the management of prostate cancer. In addition, a variety of current controversies regarding treatment are carefully explored, including whether prophylactic treatment of the pelvic lymphatics is essential, the magnitude of the effect of dose escalation, whether a benefit accrues from hypofractionation, and what evidence exists for the superiority of protons or heavy ions. Radiotherapy in Prostate Cancer: Innovative Techniques and Current Controversies is intended for both radiation oncologists and urologists with an interest in the up-to-date capabilities of modern radiation oncology for the treatment of prostate cancer.

  18. Power electronic converters PWM strategies and current control techniques

    CERN Document Server

    Monmasson, Eric

    2013-01-01

    A voltage converter changes the voltage of an electrical power source and is usually combined with other components to create a power supply. This title is devoted to the control of static converters, which deals with pulse-width modulation (PWM) techniques, and also discusses methods for current control. Various application cases are treated. The book is ideal for professionals in power engineering, power electronics, and electric drives industries, as well as practicing engineers, university professors, postdoctoral fellows, and graduate students.

  19. Spray drying technique: II. Current applications in pharmaceutical technology.

    Science.gov (United States)

    Sollohub, Krzysztof; Cal, Krzysztof

    2010-02-01

    This review presents current applications of spray drying in pharmaceutical technology. The topics discussed include the obtention of excipients and cospray dried composites, methods for increasing the aqueous solubility and bioavailability of active substances, and modified release profiles from spray-dried particles. This review also describes the use of the spray drying technique in the context of biological therapies, such as the spray drying of proteins, inhalable powders, and viable organisms, and the modification of the physical properties of dry plant extracts.

  20. Current situation of endoscopic biliary cannulation and salvage techniques for difficult cases: Current strategies in Japan.

    Science.gov (United States)

    Yasuda, Ichiro; Isayama, Hiroyuki; Bhatia, Vikram

    2016-04-01

    In the pancreatobiliary session at Endoscopic Forum Japan (EFJ) 2015, current trends of routine biliary cannulation techniques and salvage techniques for difficult biliary cannulation cases were discussed. Endoscopists from nine Japanese high-volume centers along with two overseas centers participated in the questionnaires and discussion. It was concluded that, currently, in Western countries, the wire-guided cannulation (WGC) technique is favored during initial cannulation attempts. However, the conventional technique using an endoscopic retrograde cholangiopancreatography catheter with contrast medium injection is still used as first choice at most Japanese high-volume centers. The WGC technique is used as the second choice at some institutions only. After failed biliary cannulation attempts, the initial salvage option preferred in most centers includes pancreatic guidewire placement, followed by precut techniques as the second salvage choice. Among several precut techniques, the free-hand needle knife sphincterotomy with cutting upwards from the pancreatic duct is most popular. Endoscopic ultrasonography-guided rendezvous technique is also carried out as a final salvage option at select institutions.

  1. [Current operative techniques and strategies in endocrine surgery].

    Science.gov (United States)

    Gürtler, Thomas; Weber, Markus

    2011-06-01

    Technical advances and focusing on subsets modified endocrine surgery in the last ten years tremendously. There is on one side a clear trend towards minimal invasive approaches, first of all in the surgery of the adrenal glands, where the transperitoneal or retroperitoneal laparoscopic adrenalectomy has become the gold standard for tumors up to a size of 10 cm in diameter. But also in pancreatic endocrine surgery for small tumors localized in the pancreas tail and up to a certain extend in thyroid and parathyroid surgery, laparoscopic or video assisted techniques are used. On the other side more precise techniques allow a more complete and radical removal of endocrine tissue, especially in thyroid surgery. This article presents a summary of current operative techniques and strategies in endocrine surgery.

  2. High-temperature strain measurement techniques: Current developments and challenges

    Science.gov (United States)

    Lemcoe, M. M.

    1992-01-01

    Since 1987, a very substantial amount of R&D has been conducted in an attempt to develop reliable strain sensors for the measurements of structural strains during ground testing and hypersonic flight, at temperatures up to at least 2000 deg F. Much of the effort has been focused on requirements of the NASP Program. This presentation is limited to the current sensor development work and characterization studies carried out within that program. It is basically an assessment as to where we are now and what remains to be done in the way of technical accomplishments to meet the technical challenges posed by the requirements and constraints established for the NASP Program. The approach for meeting those requirements and constraints has been multi-disciplinary in nature. It was recognized early on that no one sensor could meet all these requirements and constraints, largely because of the large temperature range (cryogenic to at least 2000 deg F) and many other factors, including the most challenging requirement that the sensor system be capable of obtaining valid 'first cycle data'. Present candidate alloys for resistance-type strain gages include Fe-Cr-Al and Pd-Cr. Although they have superior properties regarding withstanding very high temperatures, they exhibit large apparent strains that must either be accounted for or cancelled out by various techniques, including the use of a dual-element, half-bridge dummy gage, or electrical compensation networks. A significant effort is being devoted to developing, refining, and evaluating the effectiveness of those techniques over a broad range in temperature and time. In the quest to obtain first-cycle data, ways must be found to eliminate the need to prestabilize or precondition the strain gage, before it is attached to the test article. It should be noted that present NASP constraints do not permit prestabilization of the sensor, in situ. Gages are currently being 'heat treated' during manufacture in both the wire- and foil

  3. MATRIX BASED INDEXING TECHNIQUE FOR VIDEO DATA

    OpenAIRE

    2013-01-01

    Due to increasing the usage of media, the utilization of video play central role as it supports various applications. Video is the particular media which contains complex collection of objects like audio, motion, text, color and picture. Due to the rapid growth of this information video indexing process is mandatory for fast and effective retrieval. Many current indexing techniques fails to extract the needed image from the stored data set, based on the users query. Urgent attention in the fi...

  4. A resonant series counterpulse technique for high current opening switches

    Energy Technology Data Exchange (ETDEWEB)

    Dijk, E. van [Delft Univ. of Technology (Netherlands). Lab. for Power Electronics and Electrical Machines; Gelder, P. van [TNO PML-Pulse Physics Lab., Delft (Netherlands)

    1995-01-01

    A counterpulse technique for the controlled interruption of very high currents in inductive storage pulsed power systems is described and analyzed, and some simulation results of its performance are presented. The accompanying circuit comprises a pre-charged capacitor bank, connected in series with the inductive load, which has to be provided with a current pulse. Upon actuation, a resonant counterpulse current is created in the opening switch, connected in parallel with the current source and the load. In this way, the opening switch is opened at low current. A separate closing switch prevents closing of the opening switch at high voltage. Operation of the opening switch, often a mechanical switch, at low current and low voltage prevents arc erosion of the contacts. The advantage of this circuit compared to other counterpulse circuits is that the capacitor bank does not experience a voltage reversal. Electrolytic capacitors, which have a high energy density, are applied. The remaining energy of the capacitor bank after opening the opening switch, is transferred to the load. The required initial voltage of the capacitor bank is only a few hundred volts, whereas it may be above a kilovolt in other circuits. Another advantage of the method described here is that the load does not experience a pre-current, causing unwanted preheating of the load, before the resonant current is activated. At the moment, work is being performed at the Pulse Physics Laboratory to develop the resonant series counterpulse circuit for use with rail accelerators, which must be supplied with current pulses in the millisecond range up to the mega-ampere level.

  5. Imaging fast calcium currents beyond the limitations of electrode techniques.

    Science.gov (United States)

    Jaafari, Nadia; De Waard, Michel; Canepari, Marco

    2014-09-16

    The current understanding of Ca(2+) channel function is derived from the use of the patch-clamp technique. In particular, the measurement of fast cellular Ca(2+) currents is routinely achieved using whole-cell voltage-clamp recordings. However, this experimental approach is not applicable to the study of local native Ca(2+) channels during physiological changes of membrane potential in complex cells, since the voltage-clamp configuration constrains the membrane potential to a given value. Here, we report for the first time to our knowledge that Ca(2+) currents from individual cells can be quantitatively measured beyond the limitations of the voltage-clamp approach using fast Ca(2+) imaging with low-affinity indicators. The optical measurement of the Ca(2+) current was correlated with the membrane potential, simultaneously measured with a voltage-sensitive dye to investigate the activation of Ca(2+) channels along the apical dendrite of the CA1 hippocampal pyramidal neuron during the back-propagation of an action potential. To validate the method, we analyzed the voltage dependence of high- and low-voltage-gated Ca(2+) channels. In particular, we measured the Ca(2+) current component mediated by T-type channels, and we investigated the mechanisms of recovery from inactivation of these channels. This method is expected to become a reference approach to investigate Ca(2+) channels in their native physiological environment.

  6. Wavelet Based Image Denoising Technique

    Directory of Open Access Journals (Sweden)

    Sachin D Ruikar

    2011-03-01

    Full Text Available This paper proposes different approaches of wavelet based image denoising methods. The search for efficient image denoising methods is still a valid challenge at the crossing of functional analysis and statistics. In spite of the sophistication of the recently proposed methods, most algorithms have not yet attained a desirable level of applicability. Wavelet algorithms are useful tool for signal processing such as image compression and denoising. Multi wavelets can be considered as an extension of scalar wavelets. The main aim is to modify the wavelet coefficients in the new basis, the noise can be removed from the data. In this paper, we extend the existing technique and providing a comprehensive evaluation of the proposed method. Results based on different noise, such as Gaussian, Poisson’s, Salt and Pepper, and Speckle performed in this paper. A signal to noise ratio as a measure of the quality of denoising was preferred.

  7. Techniques and applications of endoscopic spine surgery. Part I:overview of current techniques

    Institute of Scientific and Technical Information of China (English)

    Kai-Xuan Liu; MD; PhD

    2013-01-01

    Background Spinal pain is a serious health and social-economic problem. Endoscopic spine surgery as a treatment option for spinal pain has gained tremendous attention and growth in the past 2 decades, and a variety of endoscopic techniques have been invented to treat a wide range of spinal conditions. Purposes The purposes of this 2-part review article are to 1 ) overview the published techniques of endoscopic spine surgery, 2 ) summarize the applications of these techniques in treating various spinal conditions, and 3 ) evaluate the clinical evidence of the safety and effectiveness of these endoscopic techniques in treating some of the most common spinal conditions. The first part of the review article provides an overview of currently most commonly used techniques. Methods We searched the PubMed database for publications concerning endoscopic spine surgery and reviewed the relevant articles published in the English language. Results Discectomy and foraminotomy are the most common types of spine surgery that can currently be done endoscopically. Endoscopic techniques have been used to treat a wide range of spinal disorders located in the lumbar, cervical, as well as the thoracic regions of the spine.

  8. Chest trauma in children: current imaging guidelines and techniques.

    LENUS (Irish Health Repository)

    Moore, Michael A

    2011-09-01

    Given the heterogeneous nature of pediatric chest trauma, the optimal imaging approach is tailored to the specific patient. Chest radiography remains the most important imaging modality for initial triage. The decision to perform a chest computed tomography scan should be based on the nature of the trauma, the child\\'s clinical condition, and the initial radiographic findings, taking the age-related pretest probabilities of serious injury into account. The principles of as low as reasonably achievable and Image Gently should be followed. The epidemiology and pathophysiology, imaging techniques, characteristic findings, and evidence-based algorithms for pediatric chest trauma are discussed.

  9. MATRIX BASED INDEXING TECHNIQUE FOR VIDEO DATA

    Directory of Open Access Journals (Sweden)

    Devarj Saravanan

    2013-01-01

    Full Text Available Due to increasing the usage of media, the utilization of video play central role as it supports various applications. Video is the particular media which contains complex collection of objects like audio, motion, text, color and picture. Due to the rapid growth of this information video indexing process is mandatory for fast and effective retrieval. Many current indexing techniques fails to extract the needed image from the stored data set, based on the users query. Urgent attention in the field of video indexing and image retrieval is the need of the hour. Here a new matrix based indexing technique for image retrieval has been proposed. The proposed method provide better result, experimental results prove this.

  10. Interactive early warning technique based on SVDD

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    After reviewing current researches on early warning,it is found that"bad" data of some systems is not easy to obtain,which makes methods proposed by these researches unsuitable for monitored systems.An interactive early warning technique based on SVDD(support vector data description)is proposed to adopt"good" data as samples to overcome the difficulty in obtaining the"bad"data.The process consists of two parts:(1)A hypersphere is fitted on"good"data using SVDD.If the data object are outside the hypersphere,it would be taken as"suspicious";(2)A group of experts would decide whether the suspicious data is"bad"or"good",early warning messages would be issued according to the decisions.And the detailed process of implementation is proposed.At last,an experiment based on data of a macroeconomic system is conducted to verify the proposed technique.

  11. Advances in Current Rating Techniques for Flexible Printed Circuits

    Science.gov (United States)

    Hayes, Ron

    2014-01-01

    Twist Capsule Assemblies are power transfer devices commonly used in spacecraft mechanisms that require electrical signals to be passed across a rotating interface. Flexible printed circuits (flex tapes, see Figure 2) are used to carry the electrical signals in these devices. Determining the current rating for a given trace (conductor) size can be challenging. Because of the thermal conditions present in this environment the most appropriate approach is to assume that the only means by which heat is removed from the trace is thru the conductor itself, so that when the flex tape is long the temperature rise in the trace can be extreme. While this technique represents a worst-case thermal situation that yields conservative current ratings, this conservatism may lead to overly cautious designs when not all traces are used at their full rated capacity. A better understanding of how individual traces behave when they are not all in use is the goal of this research. In the testing done in support of this paper, a representative flex tape used for a flight Solar Array Drive Assembly (SADA) application was tested by energizing individual traces (conductors in the tape) in a vacuum chamber and the temperatures of the tape measured using both fine-gauge thermocouples and infrared thermographic imaging. We find that traditional derating schemes used for bundles of wires do not apply for the configuration tested. We also determine that single active traces located in the center of a flex tape operate at lower temperatures than those on the outside edges.

  12. Thickness Evaluation of Aluminium Plate Using Pulsed Eddy Current Technique

    Science.gov (United States)

    Singh, Gurpartap; Bapat, Harsh Madhukar; Singh, Bhanu Pratap; Bandyopadhyay, Manojit; Puri, Rakesh Kumar; Badodkar, Deepak Narayanrao

    2013-10-01

    This paper describes a pulsed eddy current (PEC) based non-destructive testing system used for detection of thickness variation in aluminium plate. A giant magneto-resistive sensor has been used instead of pick up coil for detecting resultant magnetic field. The PEC response signals obtained from 1 to 5 mm thickness change in aluminium plate were investigated. Two time domain features, namely peak value and time to peak, of PEC response were used for extracting information about thickness variation in aluminium plate. The variation of peak value and time to peak with thickness was compared. A program was developed to display the thickness variation of the tested sample.

  13. EVALUATION OF THE RUSSIAN CURRENT TECHNIQUE ON THE TRICEPS SURAE MUSCLE IN THE PERFORMANCE OF THE VERTICAL JUMP

    OpenAIRE

    Barbosa, Aline Fernandes; Unioeste; Peretti, Ana Luiza; Unioeste; Lara, Ellis Regina Medeiros de; Unioeste; Amaro, Fernanda Lucasynski; Unioeste; Carvalho, Alberito Rodrigo de; Unioeste; Bertolini, Gladson Ricardo Flor; Universidade Estadual do Oeste do Paraná

    2014-01-01

    Neuromuscle electric stimulation is a technique for muscle strengthening based on electric stimulation of the intramuscle branches of motor-neurons that induce muscular contraction. Authors do not agree on functional gains by employing the Russian current technique. Current analysis evaluates the effect of electro-stimulation with the Russian current technique on the triceps surae muscle on the power and resistance of the vertical jump. Assay comprised 16 volunteers who were divided into a co...

  14. Disturbance observer based current controller for vector controlled IM drives

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Dal, Mehmet

    2008-01-01

    In order to increase the accuracy of the current control loop, usually, well known parameter compensation and/or cross decoupling techniques are employed for advanced ac drives. In this paper, instead of using these techniques an observer-based current controller is proposed for vector controlled...... coupling effects and increase robustness against parameters change without requiring any other compensation strategies. The experimental implementation results are provided to demonstrate validity and performance of the proposed control scheme.......In order to increase the accuracy of the current control loop, usually, well known parameter compensation and/or cross decoupling techniques are employed for advanced ac drives. In this paper, instead of using these techniques an observer-based current controller is proposed for vector controlled...

  15. The use of continuous improvement techniques: A survey-based ...

    African Journals Online (AJOL)

    International Journal of Engineering, Science and Technology ... The use of continuous improvement techniques: A survey-based study of current practices ... Prior research has focused mainly on the effect of continuous improvement practices ...

  16. Open partial nephrectomy: ancient art or currently available technique?

    Science.gov (United States)

    Seveso, Mauro; Grizzi, Fabio; Bozzini, Giorgio; Mandressi, Alberto; Guazzoni, Giorgio; Taverna, Gianluigi

    2015-12-01

    Renal cell carcinoma (RCC) accounts for 3 % of adult solid tumors, with the highest incidence between 50 and 70 years of age. Nephron-sparing surgery was initially reserved to patients with small renal masses detected in anatomically or functionally solitary kidney or in the presence of multiple bilateral tumors or hereditary forms of RCC, which posed a high risk of developing a tumor in the contralateral kidney. Nowadays, partial nephrectomy (PN) has grown up to an established approach for the treatment of small renal masses. In patients with T1a-staged RCCs, PN has proven to be associated with better survival, long-term renal function preservation with lower dialysis need or renal transplantation. Currently, most of the kidney masses are incidentally detected, up to 40 %, with smaller size due to the widespread use of imaging modalities such as ultrasound, computed tomography and magnetic resonance. Here we review the role of open PN in the management of small renal masses particularly focusing on indications, oncological outcomes and comparison with laparoscopic and robotic PN. Recent studies demonstrate that PN confers better survival, oncologic equivalence and lower risk of severe chronic kidney disease compared to radical nephrectomy becoming then the gold-standard surgical technique, even if increasingly challenged by laparoscopic and/or robot-assisted partial nephrectomy which in the hands of experts seems to achieve comparable outcome results albeit with slightly higher complication rate.

  17. Osteochondral tissue engineering with biphasic scaffold: current strategies and techniques.

    Science.gov (United States)

    Shimomura, Kazunori; Moriguchi, Yu; Murawski, Christopher D; Yoshikawa, Hideki; Nakamura, Norimasa

    2014-10-01

    The management of osteoarthritis (OA) remains challenging and controversial. Although several clinical options exist for the treatment of OA, regeneration of the damaged articular cartilage has proved difficult due to the limited healing capacity. With the advancements in tissue engineering and cell-based technologies over the past decade, new therapeutic options for patients with osteochondral lesions potentially exist. This review will focus on the feasibility of tissue-engineered biphasic scaffolds, which can mimic the native osteochondral complex, for osteochondral repair and highlight the recent development of these techniques toward tissue regeneration. Moreover, basic anatomy, strategy for osteochondral repair, the design and fabrication methods of scaffolds, as well as the choice of cells, growth factor, and materials will be discussed. Specifically, we focus on the latest preclinical animal studies using large animals and clinical trials with high clinical relevance. In turn, this will facilitate an understanding of the latest trends in osteochondral repair and contribute to the future application of such clinical therapies in patients with OA.

  18. Sub-Threshold Leakage Current Reduction Techniques In VLSI Circuits -A Survey

    Directory of Open Access Journals (Sweden)

    V.Sri Sai Harsha

    2015-09-01

    Full Text Available There is an increasing demand for portable devices powered up by battery, this led the manufacturers of semiconductor technology to scale down the feature size which results in reduction in threshold voltage and enables the complex functionality on a single chip. By scaling down the feature size the dynamic power dissipation has no effect but the static power dissipation has become equal or more than that of Dynamic power dissipation. So in recent CMOS technologies static power dissipation i.e. power dissipation due to leakage current has become a challenging area for VLSI chip designers. In order to prolong the battery life and maintain reliability of circuit, leakage current reduction is the primary goal. A basic overview of techniques used for reduction of sub-threshold leakages is discussed in this paper. Based on the surveyed techniques, one would be able to choose required and apt leakage reduction technique.

  19. Automatic parameter extraction technique for gate leakage current modeling in double gate MOSFET

    Science.gov (United States)

    Darbandy, Ghader; Gneiting, Thomas; Alius, Heidrun; Alvarado, Joaquín; Cerdeira, Antonio; Iñiguez, Benjamin

    2013-11-01

    Direct Tunneling (DT) and Trap Assisted Tunneling (TAT) gate leakage current parameters have been extracted and verified considering automatic parameter extraction approach. The industry standard package IC-CAP is used to extract our leakage current model parameters. The model is coded in Verilog-A and the comparison between the model and measured data allows to obtain the model parameter values and parameters correlations/relations. The model and parameter extraction techniques have been used to study the impact of parameters in the gate leakage current based on the extracted parameter values. It is shown that the gate leakage current depends on the interfacial barrier height more strongly than the barrier height of the dielectric layer. There is almost the same scenario with respect to the carrier effective masses into the interfacial layer and the dielectric layer. The comparison between the simulated results and available measured gate leakage current transistor characteristics of Trigate MOSFETs shows good agreement.

  20. Bases en technique du vide

    CERN Document Server

    Rouviere, Nelly

    2017-01-01

    Cette seconde édition, 20 ans après la première, devrait continuer à aider les techniciens pour la réalisation de leur système de vide. La technologie du vide est utilisée, à présent, dans de nombreux domaines très différents les uns des autres et avec des matériels très fiables. Or, elle est souvent bien peu étudiée, de plus, c'est une discipline où le savoir-faire prend tout son sens. Malheureusement la transmission par des ingénieurs et techniciens expérimentés ne se fait plus ou trop rapidement. La technologie du vide fait appel à la physique, à la chimie, à la mécanique, à la métallurgie, au dessin industriel, à l'électronique, à la thermique, etc. Cette discipline demande donc de maîtriser des techniques de domaines très divers, et ce n'est pas chose facile. Chaque installation est en soi un cas particulier avec ses besoins, sa façon de traiter les matériaux et celle d'utiliser les matériels. Les systèmes de vide sont parfois copiés d'un laboratoire à un autre et le...

  1. Current Status of Gil-Vernet Trigonoplasty Technique

    Directory of Open Access Journals (Sweden)

    Nasser Simforoosh

    2008-01-01

    Full Text Available Significant controversy exists regarding vesicoureteral reflux (VUR management, due to lack of sufficient prospective studies. The rationale for surgical management is that VUR can cause recurrent episodes of pyelonephritis and long-term renal damage. Several surgical techniques have been introduced during the past decades. Open anti-reflux operations have high success rate, exceeding 95%, and long durability. The goal of this article is to review the Gil-Vernet trigonoplasty technique, which is a simple and highly successful technique but has not gained the attention it deserves. The mainstay of this technique is approximation of medial aspects of ureteral orifices to midline by one mattress suture. A unique advantage of Gil-Vernet trigonoplasty is its bilateral nature, which results in prevention from contralateral new reflux. Regarding not altering the normal course of the ureter in Gil-Vernet procedure, later catheterization of and retrograde access to the ureter can be performed normally. There is no report of ureterovesical junction obstruction following Gil-Vernet procedure. Gil-Vernet trigonoplasty can be performed without inserting a bladder catheter and drain on an outpatient setting. Several exclusive advantages of Gil-Vernet trigonoplasty make it necessary to reconsider the technique role in VUR management.

  2. SRG POSITION SENSORLESS TECHNIQUE WITH CURRENT CHOPPING MODE

    Institute of Scientific and Technical Information of China (English)

    ZhuXuezhong; LiuDiji; GuiXiaojie; LiuChuang

    2002-01-01

    A onvel current chopping strategy for switched reluc-tance generator(SRG)-a full conducted current chopping(FCCC)scheme is presented,According to characteristics lf phase current wave of SRG generating operation,it can be generated under sensorless condition without an addi-tional circuit or a position signal algorithm.Simulational results show the feasibility of this scheme.Experimental results of a 6kW6/4configuration SRG show its simplic-ity and high reliability with little decrease in efficiency.Soit will be widely used.

  3. Fault current reduction by SFCL in a distribution system with PV using fuzzy logic technique

    Science.gov (United States)

    Mounika, M.; Lingareddy, P.

    2017-07-01

    In the modern power system, as the utilization of electric power is very wide, there is a frequent occurring of any fault or disturbance in power system. It causes a high short circuit current. Due to this fault, high currents occurs results to large mechanical forces, these forces cause overheating of the equipment. If the large size equipment are used in power system then they need a large protection scheme for severe fault conditions. Generally, the maintenance of electrical power system reliability is more important. But the elimination of fault is not possible in power systems. So the only alternate solution is to minimize the fault currents. For this the Super Conducting Fault Current Limiter using fuzzy logic technique is the best electric equipment which is used for reducing the severe fault current levels. In this paper, we simulated the unsymmetrical and symmetrical faults with fuzzy based superconducting fault current limiter. In our analysis it is proved that, fuzzy logic based super conducting fault current limiter reduces fault current quickly to a lower value.

  4. Current techniques for visualizing RNA in cells [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Lilith V.J.C. Mannack

    2016-04-01

    Full Text Available Labeling RNA is of utmost interest, particularly in living cells, and thus RNA imaging is an emerging field. There are numerous methods relying on different concepts ranging from hybridization-based probes, over RNA-binding proteins to chemo-enzymatic modification of RNA. These methods have different benefits and limitations. This review aims to outline the current state-of-the-art techniques and point out their benefits and limitations.

  5. 基于坐标变换的永磁同步电机电流传感器容错控制∗%Current Sensor Fault Detection and Isolation Technique for Permanent Magnet Synchronous Motor Based on Axes Transformation

    Institute of Scientific and Technical Information of China (English)

    马雷; 陈宇航; 张云峰

    2016-01-01

    研究了在永磁同步电机矢量控制系统之下,电流传感器的故障诊断及容错控制。针对目前双电流传感器的矢量控制系统中可能出现的软故障,提出一种基于定子坐标变换的故障诊断及容错方法,通过控制器输出的电流值与实际反馈的电流值相比较,来判断故障类型并选择相应的容错方案。仿真结果表明:该方法能准确判断出一相或两相电流传感器故障,并选择相应的实际电流计算值来完成电流闭环控制,具有较高的可行性。%A technique for fault detection and isolation to make the traditional vector control of PMSM system drive fault tolerant against one or two phase current sensor soft failure were presented. Comparison between the output current value and the feedback value, the proposed current axes transformation were expected to determine the fault type and select the appropriate fault tolerance scheme. The simulation results showed that the control system could accurately judge the one or two phase current sensor faulty and select the corresponding current calculation value to complete the current closed-loop control, with a high feasibility.

  6. Regional environmental analysis and management: New techniques for current problems

    Science.gov (United States)

    Honea, R. B.; Paludan, C. T. N.

    1974-01-01

    Advances in data acquisition and processing procedures for regional environmental analysis are discussed. Automated and semi-automated techniques employing Earth Resources Technology Satellite data and conventional data sources are presented. Experiences are summarized. The ERTS computer compatible tapes provide a very complete and flexible record of earth resources data and represent a viable medium to enhance regional environmental analysis research.

  7. A zero-voltage switching technique for minimizing the current-source power of implanted stimulators.

    Science.gov (United States)

    Çilingiroğlu, Uğur; İpek, Sercan

    2013-08-01

    The current-source power of an implanted stimulator is reduced almost to the theoretical minimum by driving the electrodes directly from the secondary port of the inductive link with a dedicated zero-voltage switching power supply. A feedback loop confined to the secondary of the inductive link adjusts the timing and conduction angle of switching to provide just the right amount of supply voltage needed for keeping the current-source voltage constant at or slightly above the compliance limit. Since drive is based on current rather than voltage, and supply-voltage update is near real-time, the quality of the current pulses is high regardless of how the electrode impedance evolves during stimulation. By scaling the switching frequency according to power demand, the technique further improves overall power consumption of the stimulator. The technique is implemented with a very simple control circuitry comprising a comparator, a Schmitt trigger and a logic gate of seven devices in addition to an on-chip switch and an off-chip capacitor. The power consumed by the proposed supply circuit itself is no larger than what the linear regulator of a conventional supply typically consumes for the same stimulation current. Still, the sum of supply and current-source power is typically between 20% and 75% of the conventional source power alone. Functionality of the proposed driver is verified experimentally on a proof-of-concept prototype built with 3.3 V devices in a 0.18 μm CMOS technology.

  8. Bulbar urethroplasty using the dorsal approach: current techniques

    Directory of Open Access Journals (Sweden)

    Guido Barbagli

    2003-04-01

    Full Text Available INTRODUCTION: The use of flaps or grafts is mandatory in patients with longer and complex strictures. In 1995-96 we described a new dorsal onlay graft urethroplasty. Over time, our original technique was better defined and changed. Now this procedure (also named Barbagli technique has been greeted with a fair amount of enthusiasm in Europe and in the United States. SURGICAL TECHNIQUE: The patient is placed in normal lithotomy position, and a midline perineo-scrotal incision is made. The bulbar urethra is then free from the bulbo-cavernous muscles, and is dissected from the corpora cavernosa. The urethra is completely mobilized from the corpora cavernosa, it is rotated 180 degrees, and is incised along its dorsal surface. The graft (preputial skin or buccal mucosa or the flap is fixed and quilted to the tunica albuginea of the corporal bodies. The right mucosal margin of the opened urethra is sutured to the right side of the patch-graft. The urethra is rotated back into its original position. The left urethral margin is sutured to the left side of the patch graft and to the corporal bodies, and the grafted area is entirely covered by the urethral plate. The bulbo-cavernous muscles are approximated over the grafted area. A 16F silicone Foley catheter is left in place. COMMENTS: Dorsal onlay graft urethroplasty is a versatile procedure that may be combined with various substitute materials like preputial skin, buccal mucosa grafts or pedicled flaps.

  9. Biomechanical Comparison of 3 Current Ankle Syndesmosis Repair Techniques.

    Science.gov (United States)

    Clanton, Thomas O; Whitlow, Scott R; Williams, Brady T; Liechti, Daniel J; Backus, Jonathon D; Dornan, Grant J; Saroki, Adriana J; Turnbull, Travis Lee; LaPrade, Robert F

    2017-02-01

    Significant debate exists regarding optimal repair for unstable syndesmosis injuries. Techniques range from screw fixation, suture-button fixation, or a combination of the two. In this study, 3 common repairs were compared using a simulated weightbearing protocol with internal and external rotation of the foot. Twenty-four lower leg specimens with mean age 54 years (range, 38-68 years) were used for testing. Following creation of a complete syndesmotic injury (AITFL, ITFL, PITFL, interosseous membrane), specimens were repaired using 1 of 3 randomly assigned techniques: (1) one 3.5-mm syndesmotic screw, (2) 1 suture-button construct, and (3) 2 divergent suture-button constructs. Repairs were cycled for 500 cycles between 7.5 Nm of internal/external rotation torque under a constant 750 N axial compressive load in a neutral dorsiflexion position. At 0, 10, 100, and 500 cycles, torsional cyclic loading was interrupted to assess torsional resistance to rotation within a physiologic range of motion (15 degrees external rotation to 10 degrees internal rotation). Torque (Nm), rotational position (degrees), and 3-dimensional data were collected throughout the testing to characterize relative spatial relationships of the tibiofibular articulation. There were no significant differences between repair techniques in resistance to internal and external rotation with respect to the intact syndesmosis. Three-dimensional analysis revealed significant differences between repair techniques for sagittal fibular translation with external rotation of the foot. Screw fixation had the smallest magnitude of posterior sagittal translation (2.5 mm), and a single suture-button construct demonstrated the largest magnitude of posterior sagittal translation (4.6 mm). Screw fixation also allowed for significantly less anterior sagittal translation with internal rotation of the foot (0.1 mm) when compared to both 1 (2.7 mm) and 2 (2.9 mm) suture-button constructs. All repairs provided comparable

  10. Maximum Bandwidth Enhancement of Current Mirror using Series-Resistor and Dynamic Body Bias Technique

    Directory of Open Access Journals (Sweden)

    V. Niranjan

    2014-09-01

    Full Text Available This paper introduces a new approach for enhancing the bandwidth of a low voltage CMOS current mirror. The proposed approach is based on utilizing body effect in a MOS transistor by connecting its gate and bulk terminals together for signal input. This results in boosting the effective transconductance of MOS transistor along with reduction of the threshold voltage. The proposed approach does not affect the DC gain of the current mirror. We demonstrate that the proposed approach features compatibility with widely used series-resistor technique for enhancing the current mirror bandwidth and both techniques have been employed simultaneously for maximum bandwidth enhancement. An important consequence of using both techniques simultaneously is the reduction of the series-resistor value for achieving the same bandwidth. This reduction in value is very attractive because a smaller resistor results in smaller chip area and less noise. PSpice simulation results using 180 nm CMOS technology from TSMC are included to prove the unique results. The proposed current mirror operates at 1Volt consuming only 102 µW and maximum bandwidth extension ratio of 1.85 has been obtained using the proposed approach. Simulation results are in good agreement with analytical predictions.

  11. Magnetic force microscopy/current contrast imaging: A new technique for internal current probing of ICs

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, A.N.; Cole, E.I. Jr.; Dodd, B.A.; Anderson, R.E.

    1993-09-01

    This invited paper describes recently reported work on the application of magnetic force microscopy (MFM) to image currents in IC conductors [1]. A computer model for MFM imaging of IC currents and experimental results demonstrating the ability to determine current direction and magnitude with a resolution of {approximately} 1 mA dc and {approximately} 1 {mu}A ac are presented. The physics of MFM signal generation and applications to current imaging and measurement are described.

  12. Chronic total occlusions — Current techniques and future directions

    Directory of Open Access Journals (Sweden)

    George Touma

    2015-06-01

    Full Text Available Chronic total occlusions (CTOs of coronary arteries represent a common and significant challenge to interventional cardiology. Medical therapy is often regarded as an adequate long term strategy in the management of these lesions with surgical intervention for refractory symptoms. Extensive collateralisation is used as a marker of distal coronary perfusion, further reinforcing non-invasive strategies. This together with relatively low percutaneous success rates outside of specialised centres has meant that rates of percutaneous intervention have remained low. Increasing evidence suggests that CTOs are not a benign entity. Further, symptom control and quality of life improve significantly with successful percutaneous revascularisation. Both factors have reignited interest in percutaneous modalities. The Japanese have been pioneers in the field of CTO intervention although their success rates have been difficult to replicate. New techniques and equipment developed in North America offer an alternative to the Japanese approach. These techniques focus on time, radiation and contrast minimisation. This review will assess the histopathology of CTO and shifting paradigms in CTO treatment strategies.

  13. Radiographic measurements of hallux angles: a review of current techniques.

    Science.gov (United States)

    Srivastava, Subodh; Chockalingam, N; El Fakhri, Tarek

    2010-03-01

    Radiographic angles are commonly used in patients with hallux valgus deformity to assess the severity, plan surgery, assess outcome and compare results. Many different manual methods have been used, but are prone to error. More recently computer-assisted methods using software have become available. To review the different methods that have been used to measure radiographic angles in hallux valgus. A general literature search using relevant key words was undertaken using databases such as Medline, Embase, Cinahl and Cochrane Library. REVIEW FINDINGS AND DISCUSSION: The manual methods used are prone to errors. The reliability can be improved by using standardised radiographic technique and measurement technique using specific reference points. Computer-assisted methods using software, might improve reliability of measurements. Further studies are needed to assess if these methods are easy to use, and to compare different software's that are available. Specifically designed software for the foot might further improve the reliability of radiographic measurements in hallux valgus. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  14. Skeletal muscle proteomics: current approaches, technical challenges and emerging techniques

    LENUS (Irish Health Repository)

    Ohlendieck, Kay

    2011-02-01

    Abstract Background Skeletal muscle fibres represent one of the most abundant cell types in mammals. Their highly specialised contractile and metabolic functions depend on a large number of membrane-associated proteins with very high molecular masses, proteins with extensive posttranslational modifications and components that exist in highly complex supramolecular structures. This makes it extremely difficult to perform conventional biochemical studies of potential changes in protein clusters during physiological adaptations or pathological processes. Results Skeletal muscle proteomics attempts to establish the global identification and biochemical characterisation of all members of the muscle-associated protein complement. A considerable number of proteomic studies have employed large-scale separation techniques, such as high-resolution two-dimensional gel electrophoresis or liquid chromatography, and combined them with mass spectrometry as the method of choice for high-throughput protein identification. Muscle proteomics has been applied to the comprehensive biochemical profiling of developing, maturing and aging muscle, as well as the analysis of contractile tissues undergoing physiological adaptations seen in disuse atrophy, physical exercise and chronic muscle transformation. Biomedical investigations into proteome-wide alterations in skeletal muscle tissues were also used to establish novel biomarker signatures of neuromuscular disorders. Importantly, mass spectrometric studies have confirmed the enormous complexity of posttranslational modifications in skeletal muscle proteins. Conclusions This review critically examines the scientific impact of modern muscle proteomics and discusses its successful application for a better understanding of muscle biology, but also outlines its technical limitations and emerging techniques to establish new biomarker candidates.

  15. Current status of iron-based superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kamihara, Yoichi, E-mail: kamihara_yoichi@appi.keio.ac.jp [Keio University, Department of Applied Physics and Physico-Informatics, Faculty of Science and Technology (Japan)

    2012-03-15

    Current status of iron-based superconductors is summarized. Although short range magnetic ordering and magnetic phase separation of Fe are controversial, (long range) magnetic and electronic phase diagrams of iron based superconductors can be classified into two-type. Antiferromagnetic ordering of itinerant Fe does not coexist with superconducting phase of SmFeAsO{sub 1 - x}F{sub x}. The very large H{sub c2} of iron-based superconductors attract us to attempts at applications.

  16. Current status of iron-based superconductors

    Science.gov (United States)

    Kamihara, Yoichi

    2012-03-01

    Current status of iron-based superconductors is summarized. Although short range magnetic ordering and magnetic phase separation of Fe are controversial, (long range) magnetic and electronic phase diagrams of iron based superconductors can be classified into two-type. Antiferromagnetic ordering of itinerant Fe does not coexist with superconducting phase of SmFeAsO1 - xFx. The very large H c2 of iron-based superconductors attract us to attempts at applications.

  17. Current trends on knowledge-based systems

    CERN Document Server

    Valencia-García, Rafael

    2017-01-01

    This book presents innovative and high-quality research on the implementation of conceptual frameworks, strategies, techniques, methodologies, informatics platforms and models for developing advanced knowledge-based systems and their application in different fields, including Agriculture, Education, Automotive, Electrical Industry, Business Services, Food Manufacturing, Energy Services, Medicine and others. Knowledge-based technologies employ artificial intelligence methods to heuristically address problems that cannot be solved by means of formal techniques. These technologies draw on standard and novel approaches from various disciplines within Computer Science, including Knowledge Engineering, Natural Language Processing, Decision Support Systems, Artificial Intelligence, Databases, Software Engineering, etc. As a combination of different fields of Artificial Intelligence, the area of Knowledge-Based Systems applies knowledge representation, case-based reasoning, neural networks, Semantic Web and TICs used...

  18. Array-based techniques for fingerprinting medicinal herbs

    Directory of Open Access Journals (Sweden)

    Xue Charlie

    2011-05-01

    Full Text Available Abstract Poor quality control of medicinal herbs has led to instances of toxicity, poisoning and even deaths. The fundamental step in quality control of herbal medicine is accurate identification of herbs. Array-based techniques have recently been adapted to authenticate or identify herbal plants. This article reviews the current array-based techniques, eg oligonucleotides microarrays, gene-based probe microarrays, Suppression Subtractive Hybridization (SSH-based arrays, Diversity Array Technology (DArT and Subtracted Diversity Array (SDA. We further compare these techniques according to important parameters such as markers, polymorphism rates, restriction enzymes and sample type. The applicability of the array-based methods for fingerprinting depends on the availability of genomics and genetics of the species to be fingerprinted. For the species with few genome sequence information but high polymorphism rates, SDA techniques are particularly recommended because they require less labour and lower material cost.

  19. Surgical treatment of scoliosis: a review of techniques currently applied

    Directory of Open Access Journals (Sweden)

    Maruyama Toru

    2008-04-01

    Full Text Available Abstract In this review, basic knowledge and recent innovation of surgical treatment for scoliosis will be described. Surgical treatment for scoliosis is indicated, in general, for the curve exceeding 45 or 50 degrees by the Cobb's method on the ground that: 1 Curves larger than 50 degrees progress even after skeletal maturity. 2 Curves of greater magnitude cause loss of pulmonary function, and much larger curves cause respiratory failure. 3 Larger the curve progress, more difficult to treat with surgery. Posterior fusion with instrumentation has been a standard of the surgical treatment for scoliosis. In modern instrumentation systems, more anchors are used to connect the rod and the spine, resulting in better correction and less frequent implant failures. Segmental pedicle screw constructs or hybrid constructs using pedicle screws, hooks, and wires are the trend of today. Anterior instrumentation surgery had been a choice of treatment for the thoracolumbar and lumbar scoliosis because better correction can be obtained with shorter fusion levels. Recently, superiority of anterior surgery for the thoracolumbar and lumbar scoliosis has been lost. Initial enthusiasm for anterior instrumentation for the thoracic curve using video assisted thoracoscopic surgery technique has faded out. Various attempts are being made with use of fusionless surgery. To control growth, epiphysiodesis on the convex side of the deformity with or without instrumentation is a technique to provide gradual progressive correction and to arrest the deterioration of the curves. To avoid fusion for skeletally immature children with spinal cord injury or myelodysplasia, vertebral wedge ostetomies are performed for the treatment of progressive paralytic scoliosis. For right thoracic curve with idiopathic scoliosis, multiple vertebral wedge osteotomies without fusion are performed. To provide correction and maintain it during the growing years while allowing spinal growth for

  20. Graph based techniques for tag cloud generation

    DEFF Research Database (Denmark)

    Leginus, Martin; Dolog, Peter; Lage, Ricardo Gomes

    2013-01-01

    Tag cloud is one of the navigation aids for exploring documents. Tag cloud also link documents through the user defined terms. We explore various graph based techniques to improve the tag cloud generation. Moreover, we introduce relevance measures based on underlying data such as ratings or citat......Tag cloud is one of the navigation aids for exploring documents. Tag cloud also link documents through the user defined terms. We explore various graph based techniques to improve the tag cloud generation. Moreover, we introduce relevance measures based on underlying data such as ratings...

  1. Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods.

    Science.gov (United States)

    Fantini, Sergio; Sassaroli, Angelo; Tgavalekos, Kristen T; Kornbluth, Joshua

    2016-07-01

    Cerebral blood flow (CBF) and cerebral autoregulation (CA) are critically important to maintain proper brain perfusion and supply the brain with the necessary oxygen and energy substrates. Adequate brain perfusion is required to support normal brain function, to achieve successful aging, and to navigate acute and chronic medical conditions. We review the general principles of CBF measurements and the current techniques to measure CBF based on direct intravascular measurements, nuclear medicine, X-ray imaging, magnetic resonance imaging, ultrasound techniques, thermal diffusion, and optical methods. We also review techniques for arterial blood pressure measurements as well as theoretical and experimental methods for the assessment of CA, including recent approaches based on optical techniques. The assessment of cerebral perfusion in the clinical practice is also presented. The comprehensive description of principles, methods, and clinical requirements of CBF and CA measurements highlights the potentially important role that noninvasive optical methods can play in the assessment of neurovascular health. In fact, optical techniques have the ability to provide a noninvasive, quantitative, and continuous monitor of CBF and autoregulation.

  2. Osteomyelitis: a review of currently used imaging techniques

    Energy Technology Data Exchange (ETDEWEB)

    Sammak, B.; Abd El Bagi, M; Al Shahed, M.; Al Nabulsi, J.; Youssef, B.; Al Thagafi, M. [Department of Radiology, Riyadh Armed Forces Hospital, Riyadh (Saudi Arabia); Hamilton, D. [Department of Medical Physics, Riyadh Armed Forces Hospital (Saudi Arabia)

    1999-06-01

    Conventional radiographs remain the initial imaging modality involved in the diagnosis of osteomyelitis. Bone scintigraphy and its specific agents did not only eliminate the problems of inherent low sensitivity of conventional radiographs, but also increased the specificity to higher degrees. Spiral CT, on the other hand, has solved several diagnostic problems, such as osteomyelitis of the sterno-clavicular junction and hidden areas in the pelvic bones. Magnetic resonance imaging with its multiplanar capability, greater anatomic details and excellent soft tissue bone marrow contrast resolution has a significant role in surgical planning and limb preservation. Ultrasound and US-guided aspiration has recently been involved in the diagnosis and management of osteomyelitis with several advantages particularly in children. Our goal in this review is to outline the ability of various imaging techniques by comparing their strengths and weaknesses in the diagnosis of osteomyelitis. Finally, we suggest various imaging algorithms for specific clinical scenarios. Spondylitis and septic arthritis are not discussed in this review. (orig.) With 7 figs., 43 refs.

  3. Current cardiac imaging techniques for detection of left ventricular mass

    Directory of Open Access Journals (Sweden)

    Celebi Aksuyek S

    2010-06-01

    Full Text Available Abstract Estimation of left ventricular (LV mass has both prognostic and therapeutic value independent of traditional risk factors. Unfortunately, LV mass evaluation has been underestimated in clinical practice. Assessment of LV mass can be performed by a number of imaging modalities. Despite inherent limitations, conventional echocardiography has fundamentally been established as most widely used diagnostic tool. 3-dimensional echocardiography (3DE is now feasible, fast and accurate for LV mass evaluation. 3DE is also superior to conventional echocardiography in terms of LV mass assessment, especially in patients with abnormal LV geometry. Cardiovascular magnetic resonance (CMR and cardiovascular computed tomography (CCT are currently performed for LV mass assessment and also do not depend on cardiac geometry and display 3-dimensional data, as well. Therefore, CMR is being increasingly employed and is at the present standard of reference in the clinical setting. Although each method demonstrates advantages over another, there are also disadvantages to receive attention. Diagnostic accuracy of methods will also be increased with the introduction of more advanced systems. It is also likely that in the coming years new and more accurate diagnostic tests will become available. In particular, CMR and CCT have been intersecting hot topic between cardiology and radiology clinics. Thus, good communication and collaboration between two specialties is required for selection of an appropriate test.

  4. Current Conveyor Based Window Comparator Circuits

    Directory of Open Access Journals (Sweden)

    Sudhanshu Maheshwari

    2016-01-01

    Full Text Available This paper introduces a new window comparator circuit utilizing a new current conveyor and two diodes, operable at ±1.25 V and capable of accurately detecting the voltage windows. Another modified circuit with distinct binary levels suited for automatic control applications is also suggested. Exhaustive simulation results showing detection of windows, as small as 50 mV and as high as 1 V, are included. Comparisons are further drawn with the traditional operational amplifier based circuit and the new circuit is found to benefit from the use of current-mode active element, namely, Extra-X Current Controlled Current Conveyor. The proposed theory is well supported through simulation results.

  5. Design automation techniques for high-resolution current folding and interpolating CMOS A/D converters

    Science.gov (United States)

    Gevaert, D.

    2007-05-01

    The design and testing of a 12-bit Analog-to-Digital (A/D) converter, in current mode, arranged in an 8-bit LSB and a 4- bit MSB architecture together with the integration of specialized test building blocks on chip allows the set up of a design automation technique for current folding and interpolation CMOS A/D converter architectures. The presented design methodology focuses on the automation for CMOS A/D building blocks in a flexible target current folding and interpolating architecture for a downscaling technology and for different quality specifications. The comprehensive understanding of all sources of mismatching in the crucial building blocks and the use of physical based mismatch modeling in the prediction of mismatch errors, more adequate and realistic sizing of all transistors will result in an overall area reduction of the A/D converter. In this design the folding degree is 16, the number of folders is 64 and the interpolation level is 4. The number of folders is reduced by creating intermediate folding signals with a 4-level interpolator based on current division techniques. Current comparators detect the zero-crossing between the differential folder output currents. The outputs of the comparators deliver a cyclic thermometer code. The digital synthesis part for decoding and error correction building blocks is a standardized digital standard cell design. The basic building blocks in the target architecture were designed in 0.35μ CMOS technology; they are suitable for topological reuse and are in an automated way downscaled into a 0.18μ CMOS technology.

  6. Metabolomics of cereals under biotic stress: current knowledge and techniques

    Directory of Open Access Journals (Sweden)

    Dirk eBalmer

    2013-04-01

    Full Text Available Prone to attacks by pathogens and pests, plants employ intricate chemical defense mechanisms consisting of metabolic adaptations. However, many plant attackers are manipulating the host metabolism to counteract defense responses and to induce favorable nutritional conditions. Advances in analytical chemistry have allowed the generation of extensive metabolic profiles during plant-pathogen and pest interactions. Thereby, metabolic processes were found to be highly specific for given tissues, species and plant-pathogen/pest interactions. The clusters of identified compounds not only serve as base in the quest of novel defense compounds, but also as markers for the characterization of the plants’ defensive state. The latter is especially useful in agronomic applications where meaningful markers are essential for crop protection. Cereals such as maize make use of their metabolic arsenal during both local and systemic defense responses, and the chemical response is highly adapted to specific attackers. Here, we summarize highlights and recent findings of metabolic patterns of cereals under pathogen and pest attack.

  7. Ultra-fast dynamic imaging: an overview of current techniques, their capabilities and future prospects

    Science.gov (United States)

    Altucci, C.; Velotta, R.; Marangos, J. P.

    2010-06-01

    In this review we attempt to sketch an overview of the various methods currently being used or under development to enable ultra-fast dynamic imaging of matter. We concentrate on those techniques which combine atomic scale spatial resolution and femtosecond or even sub-femtosecond temporal resolution. In part this review was inspired and informed by the material presented at the 'Ultrafast Dynamic Imaging II' workshop held in Ischia, Italy in April 2009, but we also have drawn on a wider background of material especially when discussing the emerging laser-based methods.

  8. A Shape Based Image Search Technique

    Directory of Open Access Journals (Sweden)

    Aratrika Sarkar

    2014-08-01

    Full Text Available This paper describes an interactive application we have developed based on shaped-based image retrieval technique. The key concepts described in the project are, imatching of images based on contour matching; iimatching of images based on edge matching; iiimatching of images based on pixel matching of colours. Further, the application facilitates the matching of images invariant of transformations like i translation ; ii rotation; iii scaling. The key factor of the system is, the system shows the percentage unmatched of the image uploaded with respect to the images already existing in the database graphically, whereas, the integrity of the system lies on the unique matching techniques used for optimum result. This increases the accuracy of the system. For example, when a user uploads an image say, an image of a mango leaf, then the application shows all mango leaves present in the database as well other leaves matching the colour and shape of the mango leaf uploaded.

  9. Smart Technique for Induction Motors Diagnosis by Monitoring the Power Factor Using Only the Measured Current

    Science.gov (United States)

    Shnibha, R. A.; Albarabar, A. S.

    2012-05-01

    This paper is concerned with accurate, early and reliable induction motor IM fault detection and diagnosis using an enhanced power parameter measurement technique. IM protection devices typically monitor the motor current and/or voltage to provide the motor protection from e.g. current overload, over/under voltage, etc. One of the interesting parameters to monitor is the operating power factor (PF) of the IM which provides better under-load protection compared to the motor current based approaches. The PF of the motor is determined by the level of the current and voltage that are drawn, and offers non-intrusive monitoring. Traditionally, PF estimation would require both voltage and the current measurements to apply the displacement method. This paper will use a method of determining the operating PF of the IM using only the measured current and the manufacturer data that are typically available from the nameplate and/or datasheet for IM monitoring. The novelty of this work lies in detecting very low phase imbalance related faults and misalignment. Much of the previous work has dealt with detecting phase imbalance faults at higher degrees of severity, i.e. voltage drops of 10% or more. The technique was tested by empirical measurements on test rig comprised a 1.1 kW variable speed three phase induction motor with varying output load (No load, 25%, 50%, 75% and 100% load). One common faults was introduced; imbalance in one phase as the electrical fault The experimental results demonstrate that the PF can be successfully applied for IM fault diagnosis and the present study shows that severity fault detection using PF is promising. The proposed method offers a potentially reliable, non-intrusive, and inexpensive CM tool which can be implemented with real-time monitoring systems

  10. IMAGE ANALYSIS BASED ON EDGE DETECTION TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    纳瑟; 刘重庆

    2002-01-01

    A method that incorporates edge detection technique, Markov Random field (MRF), watershed segmentation and merging techniques was presented for performing image segmentation and edge detection tasks. It first applies edge detection technique to obtain a Difference In Strength (DIS) map. An initial segmented result is obtained based on K-means clustering technique and the minimum distance. Then the region process is modeled by MRF to obtain an image that contains different intensity regions. The gradient values are calculated and then the watershed technique is used. DIS calculation is used for each pixel to define all the edges (weak or strong) in the image. The DIS map is obtained. This help as priority knowledge to know the possibility of the region segmentation by the next step (MRF), which gives an image that has all the edges and regions information. In MRF model,gray level l, at pixel location i, in an image X, depends on the gray levels of neighboring pixels. The segmentation results are improved by using watershed algorithm. After all pixels of the segmented regions are processed, a map of primitive region with edges is generated. The edge map is obtained using a merge process based on averaged intensity mean values. A common edge detectors that work on (MRF) segmented image are used and the results are compared. The segmentation and edge detection result is one closed boundary per actual region in the image.

  11. Rapid Tooling Technique Based on Stereolithograph Prototype

    Institute of Scientific and Technical Information of China (English)

    丁浩; 狄平; 顾伟生; 朱世根

    2001-01-01

    Rapid tooling technique based on the sterelithograph prototype is investigated. The epoxy tooling technological process was elucidated. It is analyzed in detail that the epoxy resin formula is easy to cast, curing process, and release agents. The transitional plaster model is also proposed. The mold to encrust mutual.inductors with epoxy and mold to inject plastic soapboxes was made with the technique The tooling needs very little time and cost, for the process is only to achieve the nice replica of the prototype. It is benefit for the trial and small batch of production.

  12. Language Based Techniques for Systems Biology

    DEFF Research Database (Denmark)

    Pilegaard, Henrik

    on the π calculus fragment of BioAmbients. In both cases the analyses compute very precise estimates of the temporal structure of the underlying pathways; hence they are applicable across a family of widely used bio-ware languages that descend from Milner’s Calculus of Communicating Systems. The presented...... calculi have similarly been used for the study of bio-chemical reactive systems. In this dissertation it is argued that techniques rooted in the theory and practice of programming languages, language based techniques if you will, constitute a strong basis for the investigation of models of biological...

  13. Wavelet-based technique for target segmentation

    Science.gov (United States)

    Sadjadi, Firooz A.

    1995-07-01

    Segmentation of targets embedded in clutter obtained by IR imaging sensors is one of the challenging problems in automatic target recognition (ATR). In this paper a new texture-based segmentation technique is presented that uses the statistics of 2D wavelet decomposition components of the lcoal sections of the image. A measure of statistical similarity is then used to segment the image and separate the target from the background. This technique is applied on a set of real sequential IR imagery and has shown to produce a high degree of segmentation accuracy across varying ranges.

  14. Path Based Mapping Technique for Robots

    Directory of Open Access Journals (Sweden)

    Amiraj Dhawan

    2013-05-01

    Full Text Available The purpose of this paper is to explore a new way of autonomous mapping. Current systems using perception techniques like LAZER or SONAR use probabilistic methods and have a drawback of allowing considerable uncertainty in the mapping process. Our approach is to break down the environment, specifically indoor, into reachable areas and objects, separated by boundaries, and identifying their shape, to render various navigable paths around them. This is a novel method to do away with uncertainties, as far as possible, at the cost of temporal efficiency. Also this system demands only minimum and cheap hardware, as it relies on only Infra-Red sensors to do the job.

  15. Input current interharmonics in adjustable speed drives caused by fixed-frequency modulation techniques

    DEFF Research Database (Denmark)

    Soltani, Hamid; Davari, Pooya; Loh, Poh Chiang

    2016-01-01

    Adjustable Speed Drives (ASDs) based on double-stage conversion systems may inject interharmonics distortion into the grid, other than the well-known characteristic harmonic components. The problems created by interharmonics make it necessary to find their precise sources, and, to adopt an approp......Adjustable Speed Drives (ASDs) based on double-stage conversion systems may inject interharmonics distortion into the grid, other than the well-known characteristic harmonic components. The problems created by interharmonics make it necessary to find their precise sources, and, to adopt...... an appropriate strategy for minimizing their effects. This paper investigates the ASD's input current interharmonic sources caused by applying symmetrical regularly sampled fixed-frequency modulation techniques on the inverter. The interharmonics generation process is precisely formulated and comparative results...

  16. Multiview video codec based on KTA techniques

    Science.gov (United States)

    Seo, Jungdong; Kim, Donghyun; Ryu, Seungchul; Sohn, Kwanghoon

    2011-03-01

    Multi-view video coding (MVC) is a video coding standard developed by MPEG and VCEG for multi-view video. It showed average PSNR gain of 1.5dB compared with view-independent coding by H.264/AVC. However, because resolutions of multi-view video are getting higher for more realistic 3D effect, high performance video codec is needed. MVC adopted hierarchical B-picture structure and inter-view prediction as core techniques. The hierarchical B-picture structure removes the temporal redundancy, and the inter-view prediction reduces the inter-view redundancy by compensated prediction from the reconstructed neighboring views. Nevertheless, MVC has inherent limitation in coding efficiency, because it is based on H.264/AVC. To overcome the limit, an enhanced video codec for multi-view video based on Key Technology Area (KTA) is proposed. KTA is a high efficiency video codec by Video Coding Expert Group (VCEG), and it was carried out for coding efficiency beyond H.264/AVC. The KTA software showed better coding gain than H.264/AVC by using additional coding techniques. The techniques and the inter-view prediction are implemented into the proposed codec, which showed high coding gain compared with the view-independent coding result by KTA. The results presents that the inter-view prediction can achieve higher efficiency in a multi-view video codec based on a high performance video codec such as HEVC.

  17. Current trends in ground based solar magnetometry

    Science.gov (United States)

    Gosain, Sanjay

    2016-07-01

    Continuous observations of the sun, over more than a century, have led to several important discoveries in solar astronomy. These include the discovery of the solar magnetism and its cyclic modulation, active region formation and decay and their role in energetic phenomena such as fares and coronal mass ejections (CMEs), fine structure and dynamics of the sunspots and small-scale organization of the magnetic flux in the form of flux tubes and so forth. In this article we give a brief overview of advancements in solar observational techniques in recent decades and the results obtained from the such observations. These include techniques to achieve high angular resolution, high spectral and polarimetric sensitivity and innovative new detectors. A wide range of spatial, temporal and spectral domains exploited by solar astronomers to understand the solar phenomena are discussed. Many new upcoming telescopes and instruments that are designed to address different aspects of solar physics problems are briefly described. Finally, we discuss the advantages of observing from the ground and how they can complement space-based observations.

  18. Self-Organizing Maps-based ocean currents forecasting system

    Science.gov (United States)

    Vilibić, Ivica; Šepić, Jadranka; Mihanović, Hrvoje; Kalinić, Hrvoje; Cosoli, Simone; Janeković, Ivica; Žagar, Nedjeljka; Jesenko, Blaž; Tudor, Martina; Dadić, Vlado; Ivanković, Damir

    2016-03-01

    An ocean surface currents forecasting system, based on a Self-Organizing Maps (SOM) neural network algorithm, high-frequency (HF) ocean radar measurements and numerical weather prediction (NWP) products, has been developed for a coastal area of the northern Adriatic and compared with operational ROMS-derived surface currents. The two systems differ significantly in architecture and algorithms, being based on either unsupervised learning techniques or ocean physics. To compare performance of the two methods, their forecasting skills were tested on independent datasets. The SOM-based forecasting system has a slightly better forecasting skill, especially during strong wind conditions, with potential for further improvement when data sets of higher quality and longer duration are used for training.

  19. Modulated scattering technique in the terahertz domain enabled by current actuated vanadium dioxide switches

    Science.gov (United States)

    Vitale, W. A.; Tamagnone, M.; Émond, N.; Le Drogoff, B.; Capdevila, S.; Skrivervik, A.; Chaker, M.; Mosig, J. R.; Ionescu, A. M.

    2017-02-01

    The modulated scattering technique is based on the use of reconfigurable electromagnetic scatterers, structures able to scatter and modulate an impinging electromagnetic field in function of a control signal. The modulated scattering technique is used in a wide range of frequencies up to millimeter waves for various applications, such as field mapping of circuits or antennas, radio-frequency identification devices and imaging applications. However, its implementation in the terahertz domain remains challenging. Here, we describe the design and experimental demonstration of the modulated scattering technique at terahertz frequencies. We characterize a modulated scatterer consisting in a bowtie antenna loaded with a vanadium dioxide switch, actuated using a continuous current. The modulated scatterer behavior is demonstrated using a time domain terahertz spectroscopy setup and shows significant signal strength well above 0.5 THz, which makes this device a promising candidate for the development of fast and energy-efficient THz communication devices and imaging systems. Moreover, our experiments allowed us to verify the operation of a single micro-meter sized VO2 switch at terahertz frequencies, thanks to the coupling provided by the antenna.

  20. Neural Network based Modeling and Simulation of Transformer Inrush Current

    Directory of Open Access Journals (Sweden)

    Puneet Kumar Singh

    2012-05-01

    Full Text Available Inrush current is a very important phenomenon which occurs during energization of transformer at no load due to temporary over fluxing. It depends on several factors like magnetization curve, resistant and inductance of primary winding, supply frequency, switching angle of circuit breaker etc. Magnetizing characteristics of core represents nonlinearity which requires improved nonlinearity solving technique to know the practical behavior of inrush current. Since several techniques still working on modeling of transformer inrush current but neural network ensures exact modeling with experimental data. Therefore, the objective of this study was to develop an Artificial Neural Network (ANN model based on data of switching angle and remanent flux for predicting peak of inrush current. Back Propagation with Levenberg-Marquardt (LM algorithm was used to train the ANN architecture and same was tested for the various data sets. This research work demonstrates that the developed ANN model exhibits good performance in prediction of inrush current’s peak with an average of percentage error of -0.00168 and for modeling of inrush current with an average of percentage error of -0.52913.

  1. Knowledge based systems advanced concepts, techniques and applications

    CERN Document Server

    1997-01-01

    The field of knowledge-based systems (KBS) has expanded enormously during the last years, and many important techniques and tools are currently available. Applications of KBS range from medicine to engineering and aerospace.This book provides a selected set of state-of-the-art contributions that present advanced techniques, tools and applications. These contributions have been prepared by a group of eminent researchers and professionals in the field.The theoretical topics covered include: knowledge acquisition, machine learning, genetic algorithms, knowledge management and processing under unc

  2. Flood alert system based on bayesian techniques

    Science.gov (United States)

    Gulliver, Z.; Herrero, J.; Viesca, C.; Polo, M. J.

    2012-04-01

    The problem of floods in the Mediterranean regions is closely linked to the occurrence of torrential storms in dry regions, where even the water supply relies on adequate water management. Like other Mediterranean basins in Southern Spain, the Guadalhorce River Basin is a medium sized watershed (3856 km2) where recurrent yearly floods occur , mainly in autumn and spring periods, driven by cold front phenomena. The torrential character of the precipitation in such small basins, with a concentration time of less than 12 hours, produces flash flood events with catastrophic effects over the city of Malaga (600000 inhabitants). From this fact arises the need for specific alert tools which can forecast these kinds of phenomena. Bayesian networks (BN) have been emerging in the last decade as a very useful and reliable computational tool for water resources and for the decision making process. The joint use of Artificial Neural Networks (ANN) and BN have served us to recognize and simulate the two different types of hydrological behaviour in the basin: natural and regulated. This led to the establishment of causal relationships between precipitation, discharge from upstream reservoirs, and water levels at a gauging station. It was seen that a recurrent ANN model working at an hourly scale, considering daily precipitation and the two previous hourly values of reservoir discharge and water level, could provide R2 values of 0.86. BN's results slightly improve this fit, but contribute with uncertainty to the prediction. In our current work to Design a Weather Warning Service based on Bayesian techniques the first steps were carried out through an analysis of the correlations between the water level and rainfall at certain representative points in the basin, along with the upstream reservoir discharge. The lower correlation found between precipitation and water level emphasizes the highly regulated condition of the stream. The autocorrelations of the variables were also

  3. Evaluation of lung tumor response to therapy: Current and emerging techniques.

    Science.gov (United States)

    Coche, E

    2016-10-01

    Lung tumor response to therapy may be evaluated in most instances by morphological criteria such as RECIST 1.1 on computed tomography (CT) or magnetic resonance imaging (MRI). However, those criteria are limited because they are based on tumoral dimensional changes and do not take into account other morphologic criteria such as density evaluation, functional or metabolic changes that may occur following conventional or targeted chemotherapy. New techniques such as dual-energy CT, PET-CT, MRI including diffusion-weighted MRI has to be considered into the new technical armamentarium for tumor response evaluation. Integration of all informations provided by the different imaging modalities has to be integrated and represents probably the future goal of tumor response evaluation. The aim of the present paper is to review the current and emerging imaging criteria used to evaluate the response of therapy in the field of lung cancer.

  4. Passive Target Tracking Based on Current Statistical Model

    Institute of Scientific and Technical Information of China (English)

    DENG Xiao-long; XIE Jian-ying; YANG Yu-pu

    2005-01-01

    Bearing-only passive tracking is regarded as a nonlinear hard tracking problem. There are still no completely good solutions to this problem until now. Based on current statistical model, the novel solution to this problem utilizing particle filter (PF) and the unscented Kalman filter (UKF) is proposed. The new solution adopts data fusion from two observers to increase the observability of passive tracking. It applies the residual resampling step to reduce the degeneracy of PF and it introduces the Markov Chain Monte Carlo methods (MCMC) to reduce the effect of the "sample impoverish". Based on current statistical model, the EKF, the UKF and particle filter with various proposal distributions are compared in the passive tracking experiments with two observers. The simulation results demonstrate the good performance of the proposed new filtering methods with the novel techniques.

  5. Knowledge-based techniques in software engineering

    Energy Technology Data Exchange (ETDEWEB)

    Jairam, B.N.; Agarwal, A.; Emrich, M.L.

    1988-05-04

    Recent trends in software engineering research focus on the incorporation of AI techniques. The feasibility of an overlap between AI and software engineering is examined. The benefits of merging the two fields are highlighted. The long-term goal is to automate the software development process. Some projects being undertaken towards the attainment of this goal are presented as examples. Finally, research on the Oak Ridge Reservation aimed at developing a knowledge-based software project management aid is presented. 25 refs., 1 tab.

  6. Artificial Intelligence based technique for BTS placement

    Science.gov (United States)

    Alenoghena, C. O.; Emagbetere, J. O.; Aibinu, A. M.

    2013-12-01

    The increase of the base transceiver station (BTS) in most urban areas can be traced to the drive by network providers to meet demand for coverage and capacity. In traditional network planning, the final decision of BTS placement is taken by a team of radio planners, this decision is not fool proof against regulatory requirements. In this paper, an intelligent based algorithm for optimal BTS site placement has been proposed. The proposed technique takes into consideration neighbour and regulation considerations objectively while determining cell site. The application will lead to a quantitatively unbiased evaluated decision making process in BTS placement. An experimental data of a 2km by 3km territory was simulated for testing the new algorithm, results obtained show a 100% performance of the neighbour constrained algorithm in BTS placement optimization. Results on the application of GA with neighbourhood constraint indicate that the choices of location can be unbiased and optimization of facility placement for network design can be carried out.

  7. An Observed Voting System Based On Biometric Technique

    Directory of Open Access Journals (Sweden)

    B. Devikiruba

    2015-08-01

    Full Text Available ABSTRACT This article describes a computational framework which can run almost on every computer connected to an IP based network to study biometric techniques. This paper discusses with a system protecting confidential information puts strong security demands on the identification. Biometry provides us with a user-friendly method for this identification and is becoming a competitor for current identification mechanisms. The experimentation section focuses on biometric verification specifically based on fingerprints. This article should be read as a warning to those thinking of using methods of identification without first examine the technical opportunities for compromising mechanisms and the associated legal consequences. The development is based on the java language that easily improves software packages that is useful to test new control techniques.

  8. Analytical model for Transient Current Technique (TCT) signal prediction and analysis for thin interface characterization

    Science.gov (United States)

    Bronuzzi, J.; Mapelli, A.; Sallese, J. M.

    2016-12-01

    A silicon wafer bonding technique has been recently proposed for the fabrication of monolithic silicon radiation detectors. This new process would enable direct bonding of a read-out electronic chip wafer on a highly resistive silicon substrate wafer. Therefore, monolithic silicon detectors could be fabricated in this way which would allow the free choice of electronic chips and high resistive silicon bulk, even from different providers. Moreover, a monolithic detector with a high resistive bulk would also be available. Electrical properties of the bonded interface are then critical for this application. Indeed, mobile charges generated by radiation inside the bonded bulk are expected to transit through the interface to be collected by the read-out electronics. In order to characterize this interface, the concept of Transient Current Technique (TCT) has been explored by means of numerical simulations combined with a physics based analytical model. In this work, the analytical model giving insight into the physics behind the TCT dependence upon interface traps is validated using both TCAD simulations and experimental measurements.

  9. Image encryption techniques based on the fractional Fourier transform

    Science.gov (United States)

    Hennelly, B. M.; Sheridan, J. T.

    2003-11-01

    The fractional Fourier transform, (FRT), is a generalisation of the Fourier transform which allows domains of mixed spatial frequency and spatial information to be examined. A number of method have recently been proposed in the literature for the encryption of two dimensional information using optical systems based on the FRT. Typically, these methods require random phase screen keys to decrypt the data, which must be stored at the receiver and must be carefully aligned with the received encrypted data. We have proposed a new technique based on a random shifting or Jigsaw transformation. This method does not require the use of phase keys. The image is encrypted by juxtaposition of sections of the image in various FRT domains. The new method has been compared numerically with existing methods and shows comparable or superior robustness to blind decryption. An optical implementation is also proposed and the sensitivity of the various encryption keys to blind decryption is quantified. We also present a second image encryption technique, which is based on a recently proposed method of optical phase retrieval using the optical FRT and one of its discrete counterparts. Numerical simulations of the new algorithm indicates that the sensitivity of the keys is much greater than any of the techniques currently available. In fact the sensitivity appears to be so high that optical implementation, based on existing optical signal processing technology, may be impossible. However, the technique has been shown to be a powerful method of 2-D image data encryption.

  10. Revisiting renovascular imaging for renal sympathetic denervation: current techniques and applications

    Energy Technology Data Exchange (ETDEWEB)

    Pua, Uei; Tan, Cher Heng [Tan Tock Seng Hospital, Department of Diagnostic Radiology, Singapore (Singapore); Ho, Hee Hwa; Tan, Julian Ko Beng; Ong, Paul Jau Leong [Tan Tock Seng Hospital, Department of Cardiology, Singapore (Singapore)

    2014-08-28

    Renal sympathetic denervation (RDN) is an emerging technique in the treatment of resistant hypertension, most commonly performed using an endovascular approach. Clinical and anatomical criteria for RDN are well established and imaging plays an integral role in selecting patients with suitable anatomy, procedural planning and device selection. Nevertheless, the current body of literature surrounding imaging related to RDN remains limited. The purpose of this article is to illustrate the expectations and limitations of various imaging techniques, including Doppler ultrasound, CT angiography, MR angiography and newer techniques such as non-contrast MR angiography, in the context of RDN. (orig.)

  11. A Review of Novel Leakage Current Suppression Techniques for Transformerless Photovoltaic Inverters

    Institute of Scientific and Technical Information of China (English)

    WU Weiyang; GUO Xiaoqiang

    2012-01-01

    In recent years, the transformerless PV inverters have been paid more attention due to cost and size reduction, as well as efficiency improvement compared with the conventional transformer ones. Leakage current suppression is one of the most important techniques for transformerless grid connected photovoltaic systems. The objective of this paper is to present a comprehensive review of the recently developed solution to the leakage current reduction. First of all, the common-mode model of the PV system is described to explain how the leakage current generates.

  12. Design of Current Controller for Two Quadrant DC Motor Drive by Using Model Order Reduction Technique

    CERN Document Server

    Ramesh, K; Nirmalkumar, A; Gurusamy, G

    2010-01-01

    In this paper, design of current controller for a two quadrant DC motor drive was proposed with the help of model order reduction technique. The calculation of current controller gain with some approximations in the conventional design process is replaced by proposed model order reduction method. The model order reduction technique proposed in this paper gives the better controller gain value for the DC motor drive. The proposed model order reduction method is a mixed method, where the numerator polynomial of reduced order model is obtained by using stability equation method and the denominator polynomial is obtained by using some approximation technique preceded in this paper. The designed controllers responses were simulated with the help of MATLAB to show the validity of the proposed method.

  13. Current knowledge and importance of dGEMRIC techniques in diagnosis of hip joint diseases

    Energy Technology Data Exchange (ETDEWEB)

    Zilkens, Christoph; Krauspe, Ruediger; Bittersohl, Bernd [University of Duesseldorf, Medical Faculty, Department of Orthopedic Surgery, Duesseldorf (Germany); Tiderius, Carl Johann [Lund University Hospital, Department of Orthopedic Surgery, Lund (Sweden)

    2015-08-15

    Accurate assessment of early hip joint cartilage alterations may help optimize patient selection and follow-up of hip joint preservation surgery. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is sensitive to the glycosaminoglycan content in cartilage that is lost early in the development of osteoarthritis (OA). Hence, the dGEMRIC technique holds promise for the development of new diagnostic and therapeutic procedures. However, because of the location of the hip joint deep within the body and due to the fairly thin cartilage layers that require high spatial resolution, the diagnosis of early hip joint cartilage alterations may be problematic. The purpose of this review is to outline the current status of dGEMRIC in the assessment of hip joint cartilage. A literature search was performed with PubMed, using the terms ''cartilage, osteoarthritis, hip joint, MRI, and dGEMRIC'', considering all levels of studies. This review revealed that dGEMRIC can be reliably used in the evaluation of early stage cartilage pathology in various hip joint disorders. Modifications in the technique, such as the operation of three-dimensional imaging and dGEMRIC after intra-articular contrast medium administration, have expanded the range of application. Notably, the studies differ considerably in patient selection and technical prerequisites. Furthermore, there is a need for multicenter prospective studies with the required technical conditions in place to establish outcome based dGEMRIC data to obtain, in conjunction with clinical data, reliable threshold values for normal and abnormal cartilage, and for hips that may benefit from conservative or surgical treatment. (orig.)

  14. DAQ System of Current Based on MNSR

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The flux or power should be acquired using the detector in the operation of MNSR. As usual, the signal of detector is current, and it is very width range with 10-11-10-6 A. It is hard to satisfy the linearity to amplify this signal by using fix gain

  15. 脉冲涡流测厚技术%Thickness Measurement Technique by Pulsed Eddy Current

    Institute of Scientific and Technical Information of China (English)

    吴鑫; 李方奇; 石坤; 谢基龙; 李浩

    2009-01-01

    脉冲涡流检测技术具有频谱宽、信号穿透能力强以及精确度好等优点.对脉冲涡流测厚技术进行了仿真,即针对脉冲涡流测厚系统,建立了有限元分析模型,仿真分析了检测线圈上的电压的衰减规律,得到了检测线圈上的电压随被测体厚度的变化规律,确定了两者之间的定量关系.分析了提离距离、检测线圈参数和脉冲涡流频率对检测结果的影响.该研究为将来进行脉冲涡流测厚仪的研制提供了理论依据和数学模型.%Pulsed eddy current technique had quite a few advantages such as wide spectrum, strong penetration,high accuracy. The experiment was carried out to study the metal thickness measurement of PEC, and a finite element model for the system of the metal thickness measurement of PEC was established. Based on the finite element model established, this thesis analyzed the attenuation law of the voltage in receiving coil By changing the thickness of tested bodies, the relationship between the voltage of receiving coil and the thickness of the testedbodies was analyzed, and also the factors that affected the measuring results such as lift-off distance, parameters of testing coil and frequency of pulsed eddy current were analyzed in detail It provided a theoretical basis and mathematical models for the future development of the PEC gage.

  16. Enhancing the effectiveness of IST through risk-based techniques

    Energy Technology Data Exchange (ETDEWEB)

    Floyd, S.D.

    1996-12-01

    Current IST requirements were developed mainly through deterministic-based methods. While this approach has resulted in an adequate level of safety and reliability for pumps and valves, insights from probabilistic safety assessments suggest a better safety focus can be achieved at lower costs. That is, some high safety impact pumps and valves are currently not tested under the IST program and should be added, while low safety impact valves could be tested at significantly greater intervals than allowed by the current IST program. The nuclear utility industry, through the Nuclear Energy Institute (NEI), has developed a draft guideline for applying risk-based techniques to focus testing on those pumps and valves with a high safety impact while reducing test frequencies on low safety impact pumps and valves. The guideline is being validated through an industry pilot application program that is being reviewed by the U.S. Nuclear Regulatory Commission. NEI and the ASME maintain a dialogue on the two groups` activities related to risk-based IST. The presenter will provide an overview of the NEI guideline, discuss the methodological approach for applying risk-based technology to IST and provide the status of the industry pilot plant effort.

  17. Optimization of RF power absorption by optimization techniques using the lower hybrid current drive of FTU

    Energy Technology Data Exchange (ETDEWEB)

    Centioli, C. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Iannone, F. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Mazza, G. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Panella, M. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Pangione, L. [Dipartimento di Informatica, Sistemi e Produzione, Universita di Roma, Tor Vergata, Via del Politecnico 1, 00133 Rome (Italy)]. E-mail: pangione@frascati.enea.it; Podda, S. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Tuccillo, A. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Vitale, V. [Associazione Euratom/ENEA Sulla Fusione, Centro Ricerche Frascati, Via E. Fermi 45, CP 65, 00044 Frascati, Rome (Italy); Zaccarian, L. [Dipartimento di Informatica, Sistemi e Produzione, Universita di Roma, Tor Vergata, Via del Politecnico 1, 00133 Rome (Italy)

    2005-11-15

    In this paper, we will report on the experimental results arising from the implementation of optimization techniques to maximize the RF power coupling versus the plasma conditions in the FTU experimental facility. These experiments are carried out by employing the open-source Linux-RTAI control system currently running on the FTU digital feedback loop. The RF power source under consideration is a lower hybrid system (LH) based on six gyrotrons with a nominal power output capability of 1.1 MW each. The optimization of the coupling level between the plasma and the emitting antenna reduces the reflected power, thus maximizing the heating effects in addition to avoiding danger to the emitter (equivalently, annoying safety shutdowns of the system). To this aim, the plasma displacement is modified by suitably adjusting the reference input to the stabilizing feedback, according to a steepest descent algorithm. It will be shown in the paper how this algorithm achieves a satisfactory level of robustness with respect to measurement errors and well performs both in simulation and in experimental tests, thus leading to an improved effectiveness of the RF heating system.

  18. Development of Capacitor Charging Supply Based on Constant Current Technique

    Institute of Scientific and Technical Information of China (English)

    YANG; Jing-he; ZHANG; Li-feng; YANG; Sheng; TONG; Xun-hua; YU; Guo-long

    2013-01-01

    As the pulse power supply in electron linear accelerator,the line-type pulse modulator is used to produce the high voltage pulse which come into being when the pulse forming net(PFN)is discharged.The frequency and stability is related to the PFN charging system.The breakthrough in high power switch devices makes it possible that applying switch devices are into pulse power field.In line-type high voltage

  19. Pulsed remote field eddy current technique applied to non-magnetic flat conductive plates

    Science.gov (United States)

    Yang, Binfeng; Zhang, Hui; Zhang, Chao; Zhang, Zhanbin

    2013-12-01

    Non-magnetic metal plates are widely used in aviation and industrial applications. The detection of cracks in thick plate structures, such as multilayered structures of aircraft fuselage, has been challenging in nondestructive evaluation societies. The remote field eddy current (RFEC) technique has shown advantages of deep penetration and high sensitivity to deeply buried anomalies. However, the RFEC technique is mainly used to evaluate ferromagnetic tubes. There are many problems that should be fixed before the expansion and application of this technique for the inspection of non-magnetic conductive plates. In this article, the pulsed remote field eddy current (PRFEC) technique for the detection of defects in non-magnetic conducting plates was investigated. First, the principle of the PRFEC technique was analysed, followed by the analysis of the differences between the detection of defects in ferromagnetic and non-magnetic plain structures. Three different models of the PRFEC probe were simulated using ANSYS. The location of the transition zone, defect detection sensitivity and the ability to detect defects in thick plates using three probes were analysed and compared. The simulation results showed that the probe with a ferrite core had the highest detecting ability. The conclusions derived from the simulation study were also validated by conducting experiments.

  20. Imaging Techniques in Psoriatic Arthritis: Update 2012-2014 on Current Status and Future Prospects.

    Science.gov (United States)

    Aleo, Elena; Migone, Stefania; Prono, Valentina; Barbieri, Francesca; Garlaschi, Giacomo; Cimmino, Marco A

    2015-11-01

    By providing additional and more sensitive information over clinical examination, imaging techniques are useful in the assessment of patients with psoriatic arthritis (PsA) and have been increasingly used to obtain additional clues to its pathogenesis. This review describes the current status and future development of conventional radiography, computed tomography, magnetic resonance imaging, positron emission tomography, and other novel techniques in the evaluation of PsA, with a focus on their use in diagnosing, monitoring, and predicting disease course and followup treatment response. The role and applications of ultrasonography are outside the scope and are reviewed elsewhere in these proceedings.

  1. Recanalization of Chronic Total Occlusion Lesions: A Critical Appraisal of Current Devices and Techniques

    Science.gov (United States)

    2016-01-01

    Chronic Total Occlusion (CTO) has been considered as one of the “final frontier” in interventional cardiology. Until recently, the patients with CTO are often managed surgically or medically due to lack of published evidence of clinical benefits and lower success rate of percutaneous recanalization of CTO. However, the introduction of enhanced guidewires, microcatheters combined with novel specialized devices and techniques reduce the number of unapproachable CTO. In this review article, current techniques and devices of percutaneous recanalization of CTO have been systematically summarized, which may help budding interventional cardiologists to theoretically understand these complex procedures and to deliver safe and effective percutaneous management of CTO to the patients. PMID:27790503

  2. Investigations of Tracking Phenomena in Silicone Rubber Using Moving Average Current Technique

    Institute of Scientific and Technical Information of China (English)

    R. Sarathi; S. Chandrasekar

    2004-01-01

    In the present work, tracking phenomenon in Silicone rubber material has been studied under AC and DC voltage, with ammonium chloride as a contaminant. It is observed that the tracking is more severe under the DC voltages. The tracking time is less under negative DC compared to the positive DC voltage. The tracking mechanism is explained in detail. The leakage current during the tracking studies was as measured and the moving average technique was adopted to understand the trend in current flow. The leakage current magnitude is high with thermally aged specimens compared to the virgin specimen, irrespective of the type of applied voltage. It is realized that the tracking time and the leakage current magnitude shows an inverse relationship.

  3. Dynamics-based Nondestructive Structural Monitoring Techniques

    Science.gov (United States)

    2012-06-21

    in the practice of non- destructive evaluation ( NDE ) and structural health monitoring (SHM). Guided wave techniques have several advantages over...conventional bulk wave ultrasonic NDE /SHM techniques. Some of these advantages are outlined in Table I. However, in addition to the advantages of...PVDF transducers for SHM applications with controlled guided wave modes and frequencies [7]. Wilcox used EMATs with circular coils in a guided wave

  4. DCT-based cyber defense techniques

    Science.gov (United States)

    Amsalem, Yaron; Puzanov, Anton; Bedinerman, Anton; Kutcher, Maxim; Hadar, Ofer

    2015-09-01

    With the increasing popularity of video streaming services and multimedia sharing via social networks, there is a need to protect the multimedia from malicious use. An attacker may use steganography and watermarking techniques to embed malicious content, in order to attack the end user. Most of the attack algorithms are robust to basic image processing techniques such as filtering, compression, noise addition, etc. Hence, in this article two novel, real-time, defense techniques are proposed: Smart threshold and anomaly correction. Both techniques operate at the DCT domain, and are applicable for JPEG images and H.264 I-Frames. The defense performance was evaluated against a highly robust attack, and the perceptual quality degradation was measured by the well-known PSNR and SSIM quality assessment metrics. A set of defense techniques is suggested for improving the defense efficiency. For the most aggressive attack configuration, the combination of all the defense techniques results in 80% protection against cyber-attacks with PSNR of 25.74 db.

  5. A novel biphasic-current-pulse calibration technique for electrical neural stimulation.

    Science.gov (United States)

    Maohua Ren; Jinyong Zhang; Lei Wang; Zhenyu Wang

    2014-01-01

    One of the major challenge in neural prosthetic device design is to ensure charge-balanced stimulation. This paper presents a new calibration technique to minimize the mismatch between anodic and cathodic current amplitudes. The proposed circuit mainly consists of a digital and an analog calibration, where a successive approximation register (SAR) logic and a comparator are used in digital calibration while a source follower is adopted in analog calibration. With a 0.18 μm high voltage CMOS process, the simulation shows that the maximum current mismatch is 45 nA (<0.05%).

  6. New Approach to Low-Power & Leakage Current Reduction Technique for CMOS Circuit Design

    Directory of Open Access Journals (Sweden)

    Sujata Prajapati

    2014-02-01

    Full Text Available Leakage power dissipation has become major portion of total power consumption in the integrated device and is expected to grow exponentially in the next decade as per International Technology Roadmap for Semiconductors (IRTS. This directly affects the battery operated devices as it has long idle times. Thus by scaling down the threshold voltage has tremendously increased the sub threshold leakage current thereby making the static power dissipation very high. To overcome this problem several techniques has been proposed to overcome this high leakage power dissipation. A comprehensive survey and analysis of various leakage power minimization techniques is presented in this paper. Of the available techniques, eight techniques are considered for the analysis namely, Multi Threshold CMOS (MTCMOS, Super Cut-off CMOS (SCCMOS, Forced Transistor Stacking (FTS and Sleepy Stack (SS, Sleepy keeper (SK, Dual Stack (OS, and LECTOR. From the results, it is observed that Lector techniques produces lower power dissipation than the other techniques due to the ability of power gating.

  7. SQUID based cryogenic current comparator for measurements of the dark current of superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Vodel, W.; Nietzsche, S.; Neubert, R.; Nawrodt, R. [Friedrich Schiller Univ. Jena (Germany); Peters, A. [GSI Darmstadt (Germany); Knaack, K.; Wendt, M.; Wittenburg, K. [DESY Hamburg (Germany)

    2005-07-01

    The linear accelerator technology, based on super-conducting L-band (1.3 GHz) is currently under study at DESY (Hamburg, Germany). The two 10 km long main Linacs will be equipped with a total of nearly 20.000 cavities. The dark current due to the emission of electrons in these high gradient field super-conducting cavities is an unwanted particle source. A newly high performance SQUID based measurement system for detecting dark currents is proposed. It makes use of the Cryogenic Current Comparator principle and senses dark currents in the pA range with a measurement bandwidth of up to 70 kHz. The use of a cryogenic current comparator as dark current sensor has some important advantages: -) the measurement of the absolute value of the dark current, -) the non-dependence on the electron trajectories, -) the accurate absolute calibration with an additional wire loop, and -) extremely high resolution.

  8. Development of fiber-optic current sensing technique and its applications in electric power systems

    Science.gov (United States)

    Kurosawa, Kiyoshi

    2014-03-01

    This paper describes the development and applications of a fiber-optic electric current sensing technique with the stable properties and compact, simple, and flexible structure of the sensing device. The special characteristics of the sensors were achieved by use of the special low birefringence fiber as the Faraday-effect sensing element and were also achieved with creation of sensing schemes which matched with the features of the fiber. Making use of the excellent features of the sensing technique, various current monitoring devices and systems were developed and applied practically for the control and maintenance in the electric power facility. In this paper, the design and performance of the sensing devices are introduced first. After that, examples of the application systems practically applied are also introduced, including fault section/point location systems for power transmission cable lines.

  9. Nasal base narrowing: the combined alar base excision technique.

    Science.gov (United States)

    Foda, Hossam M T

    2007-01-01

    To evaluate the role of the combined alar base excision technique in narrowing the nasal base and correcting excessive alar flare. The study included 60 cases presenting with a wide nasal base and excessive alar flaring. The surgical procedure combined an external alar wedge resection with an internal vestibular floor excision. All cases were followed up for a mean of 32 (range, 12-144) months. Nasal tip modification and correction of any preexisting caudal septal deformities were always completed before the nasal base narrowing. The mean width of the external alar wedge excised was 7.2 (range, 4-11) mm, whereas the mean width of the sill excision was 3.1 (range, 2-7) mm. Completing the internal excision first resulted in a more conservative external resection, thus avoiding any blunting of the alar-facial crease. No cases of postoperative bleeding, infection, or keloid formation were encountered, and the external alar wedge excision healed with an inconspicuous scar that was well hidden in the depth of the alar-facial crease. Finally, the risk of notching of the alar rim, which can occur at the junction of the external and internal excisions, was significantly reduced by adopting a 2-layered closure of the vestibular floor (P = .01). The combined alar base excision resulted in effective narrowing of the nasal base with elimination of excessive alar flare. Commonly feared complications, such as blunting of the alar-facial crease or notching of the alar rim, were avoided by using simple modifications in the technique of excision and closure.

  10. Theory and signal processing of acoustic correlation techniques for current velocity measurement

    Institute of Scientific and Technical Information of China (English)

    ZHU Weiqing; FENG Lei; WANG Changhong; WANG Yuling; QIU Wei

    2008-01-01

    A theoretical model and signal processing of acoustic correlation measurements to estimate current velocity are discussed. The sonar space-time correlation function of vol-ume reverberations within Fraunhofer zone is derived. The function, which is in exponential forms, is the theoretical model of acoustic correlation measurements. The characteristics of the correlation values around the maximum of the amplitude of the correlation function, where most information about current velocity is contained, are primarily analyzed. Localized Least Mean Squares (LLMS) criterion is put forward for velocity estimation. Sequential Quadratic Programming (SQP) method is adopted as the optimization method. So the systematic sig-nal processing method of acoustic correlation techniques for current velocity measurement is established. A prototype acoustic correlation current profiler (ACCP) underwent several sea trials, the results show that theoretical model approximately coincides with experimental re-sults. Current profiles including the speed and direction from ACCP are compared with those from acoustic Doppler current profiler (ADCP). The current profiles by both instruments agree reasonably well. Also, the standard deviation of velocity measurement by ACCP is statistically calculated and it is a little larger than predicted value.

  11. Limiting current technique in the research of mass/heat transfer in nanofluid

    Science.gov (United States)

    Wilk, J.; Grosicki, S.

    2016-09-01

    In the paper the authors focused on the application of the electrochemical limiting diffusion current technique to the study of mass transfer in nanofluid flow. As mass and heat transfer are analogical phenomena, analysing mass transfer helps understand heat transfer processes in nanofluids. The paper begins with a short review of the available literature on the subject followed by the authors' results of mass transfer coefficient measurements and the conclusions concerning mass/heat transfer enhancement in nanofluids.

  12. Lipid-based antifungal agents: current status.

    Science.gov (United States)

    Arikan, S; Rex, J H

    2001-03-01

    Immunocompromised patients are well known to be predisposed to developing invasive fungal infections. These infections are usually difficult to diagnose and more importantly, the resulting mortality rate is high. The limited number of antifungal agents available and their high rate of toxicity are the major factors complicating the issue. However, the development of lipid-based formulations of existing antifungal agents has opened a new era in antifungal therapy. The best examples are the lipid-based amphotericin B preparations, amphotericin B lipid complex (ABLC; Abelcet), amphotericin B colloidal dispersion (ABCD; Amphotec or Amphocil), and liposomal amphotericin B (AmBisome). These formulations have shown that antifungal activity is maintained while toxicity is reduced. This progress is followed by the incorporation of nystatin into liposomes. Liposomal nystatin formulation is under development and studies of it have provided encouraging data. Finally, lipid-based formulations of hamycin, miconazole, and ketoconazole have been developed but remain experimental. Advances in technology of liposomes and other lipid formulations have provided promising new tools for management of fungal infections.

  13. GIS Based Stereoscopic Visualization Technique for Weather Radar Data

    Science.gov (United States)

    Lim, S.; Jang, B. J.; Lee, K. H.; Lee, C.; Kim, W.

    2014-12-01

    As rainfall characteristic is more quixotic and localized, it is important to provide a prompt and accurate warning for public. To monitor localized heavy rainfall, a reliable disaster monitoring system with advanced remote observation technology and high-precision display system is needed. To advance even more accurate weather monitoring using weather radar, there have been growing concerns regarding the real-time changes of mapping radar observations on geographical coordinate systems along with the visualization and display methods of radar data based on spatial interpolation techniques and geographical information system (GIS). Currently, the method of simultaneously displaying GIS and radar data is widely used to synchronize the radar and ground systems accurately, and the method of displaying radar data in the 2D GIS coordinate system has been extensively used as the display method for providing weather information from weather radar. This paper proposes a realistic 3D weather radar data display technique with higher spatiotemporal resolution, which is based on the integration of 3D image processing and GIS interaction. This method is focused on stereoscopic visualization, while conventional radar image display works are based on flat or two-dimensional interpretation. Furthermore, using the proposed technique, the atmospheric change at each moment can be observed three-dimensionally at various geological locations simultaneously. Simulation results indicate that 3D display of weather radar data can be performed in real time. One merit of the proposed technique is that it can provide intuitive understanding of the influence of beam blockage by topography. Through an exact matching each 3D modeled radar beam with 3D GIS map, we can find out the terrain masked areas and accordingly it facilitates the precipitation correction from QPE underestimation caused by ground clutter filtering. It can also be expected that more accurate short-term forecasting will be

  14. A Comparative Study of Three Vibration Based Damage Assessment Techniques

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Rytter, A.

    Three different vibration based damage assessment techniques have been compared. One of the techniques uses the ratios between changes in experimentally and theoretically estimated natural frequencies, respectively, to locate a damage. The second technique relies on updating of an FEM based...

  15. Carrier phase shifted SPWM based on current sourced multi-modular converter for active power filter

    Institute of Scientific and Technical Information of China (English)

    王立乔; 李建林; 张仲超

    2004-01-01

    A novel current-source active power filter(APF)based on multi-modular converter with carrier phase-shifted SPWM(CPS-SPWM)technique is proposed.With this technique,the effect of equivalent high switching frequency converter is obtained with low switching frequency converter.It is very promising in current-source APF that adopt superconducting magnetic energy storage component.

  16. Implementations of artificial neural networks using current-mode pulse width modulation technique.

    Science.gov (United States)

    El-Masry, E I; Yang, H K; Yakout, M A

    1997-01-01

    The use of a current-mode pulse width modulation (CM-PWM) technique to implement analog artificial neural networks (ANNs) is presented. This technique can be used to efficiently implement the weighted summation operation (WSO) that are required in the realization of a general ANN. The sigmoidal transformation is inherently performed by the nonlinear transconductance amplifier, which is a key component in the current integrator used in the realization of WSO. The CM-PWM implementation results in a minimum silicon area, and therefore is suitable for very large scale neural systems. Other pronounced features of the CM-PWM implementation are its easy programmability, electronically adjustable gains of neurons, and modular structures. In this paper, all the current-mode CMOS circuits (building blocks) required for the realization of CM-PWM ANNs are presented and simulated. Four modules for modular design of ANNs are introduced. Also, it is shown that the CM-PWM technique is an efficient method for implementing discrete-time cellular neural networks (DT-CNNs). Two application examples are given: a winner-take-all circuit and a connected component detector.

  17. A new circuit technique for reduced leakage current in Deep Submicron CMOS technologies

    Directory of Open Access Journals (Sweden)

    A. Schmitz

    2005-01-01

    Full Text Available Modern CMOS processes in the Deep Submicron regime are restricted to supply voltages below 2 volts and further to account for the transistors' field strength limitations and to reduce the power per logic gate. To maintain the high switching performance, the threshold voltage must be scaled according with the supply voltage. However, this leads to an increased subthreshold current of the transistors in standby mode (VGS=0. Another source of leakage is gate current, which becomes significant for gate oxides of 3nm and below. We propose a Self-Biasing Virtual Rails (SBVR - CMOS technique which acts like an adaptive local supply voltage in case of standby mode. Most important sources of leakage currents are reduced by this technique. Moreover, SBVR-CMOS is capable of conserving stored information in sleep mode, which is vital for memory circuits. Memories are exposed to radiation causing soft errors. This well-known problem becomes even worse in standby mode of typical SRAMs, that have low driving performance to withstand alpha particle hits. In this paper, a 16-transistor SRAM cell is proposed, which combines the advantage of extremely low leakage currents with a very high soft error stability.

  18. [Current status of mangrove germplasm resources and key techniques for mangrove seedling propagation in China].

    Science.gov (United States)

    Hu, Hong-You; Chen, Shun-Yang; Wang, Wen-Qing; Dong, Ke-Zuan; Lin, Guang-Hui

    2012-04-01

    Mangrove germplasm and nursery operation are the foundations of all mangrove ecological restoration projects. Based on the existing literatures and our own experiences, and by using cluster analysis and other methods, this paper assessed the current status of the mangrove germplasm resources and the key techniques for mangrove seedlings propagation in China. In China, the mangrove communities could be divided into 4 types, including low temperature tolerant widespread type, widespread type, thermophilic widespread type, and tropical type, and the mangrove distribution sites could be divided into 5 regions, i. e., eastern Hainan coast, Beibuwan Gulf coast, Pearl River estuary and eastern Guangdong coast, southern Fujian and Taiwan coast, and eastern Fujian and southern Zhejiang coast. The mangroves in Beibuwan Gulf coast region took up 75.3% of the total mangrove germplasm resources in the country. At present, the percentage of the mangrove species applied for seedling propagation in China was estimated at 52.6%, most of which were of viviparous species. The six key steps in mangrove nursery operation included the selection of proper seedling propagation methods, the collection and storage of seeds or propagules, the ways of raising seedlings, the management of water and salinity, the control of diseases and pests, and the prevention of cold damage during winter. The structure, functions, and applieations of the present five types of mangrove nurseries, including dry land nursery, mangrove tidal nursery, mudflat nursery, Jiwei pond nursery, and Spartina mudflat nursery, were also analyzed, which could provide guidance for the integrated management of mangrove ecological restoration engineering.

  19. High impulse voltage and current measurement techniques fundamentals, measuring instruments, measuring methods

    CERN Document Server

    Schon, Klaus

    2013-01-01

    Equipment to be installed in electric power-transmission and distribution systems must pass acceptance tests with standardized high-voltage or high-current test impulses which simulate the stress on the insulation caused by external lightning discharges and switching operations in the grid. High impulse voltages and currents are also used in many other fields of science and engineering for various applications. Therefore, precise impulse-measurement techniques are necessary, either to prevent an over- or understressing of the insulation or to guarantee the effectiveness and quality of the application. The book deals with: principal generator circuits for generating high-voltage and high-current impulses measuring systems and their calibration according to IEC 60060 and IEC 62475 methods of estimating uncertainties of measurement mathematical and experimental basis for characterizing the transfer behavior of spatially extended systems used for measuring fast transients. This book is intended for engineers and ...

  20. Current status of molecular biological techniques for plant breeding in the Republic of Korea

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Seong-Han; Lee, Si-Myung; Park, Bum-Seok; Yun, In-Sun; Goo, Doe-Hoe; Kim, Seok-Dong [Rural Development Administration, National Institute of Agricultural Science and Technology, Suwon (Korea)

    2002-02-01

    Classical plant breeding has played an important role in developing new varieties in current agriculture. For decades, the technique of cross-pollination has been popular for breeding in cereal and horticultural crops to introduce special traits. However, recently the molecular techniques get widely accepted as an alternative tool in both introducing a useful trait for developing the new cultivars and investigating the characteristics of a trait in plant, like the identification of a gene. Using the advanced molecular technique, several genetically modified (GM) crops (e.g., Roundup Ready Soybean, YieldGard, LibertyLink etc.) became commercially cultivated and appeared in the global market since 1996. The GM crops, commercially available at the moment, could be regarded as successful achievements in history of crop breeding conferring the specific gene into economically valuable crops to make them better. Along with such achievements, on the other hand these new crops have also caused the controversial debate on the safety of GM crops as human consumption and environmental release as well. Nevertheless, molecular techniques are widespread and popular in both investigating the basic science of plant biology and breeding new varieties compared to their conventional counterparts. Thus, the Department of Bioresources at the National Institute of Agricultural Science and Technology (NIAST) has been using the molecular biological techniques as a complimentary tool for the improvement of crop varieties for almost two decades. (author)

  1. An Improved Variable-Frequency Drive Based on Current Tracking

    Directory of Open Access Journals (Sweden)

    Zhiwei He

    2013-11-01

    Full Text Available Variable frequency devices are widely used in many power systems. A current tracking based VFD is proposed in this paper. The output current is firstly fed back and compared with a standard sine wave, the difference of them is then used for a PI regulator to control the PWM signal, so as to change the output current accordingly to make it approach the standard sine wave. Simulation and experiments results show that the current tracking VFD not only has a fast dynamic response, high current tracking precision, current limiting ability, but also has small distortion of the output sine wave current and low loss of the motor.    

  2. The current state of evidence-based pediatric surgery.

    Science.gov (United States)

    Ostlie, Daniel J; St Peter, Shawn D

    2010-10-01

    The efficiency of medical care in the United States has become intensely scrutinized with expectations from patients, families, payors, lawmakers, and, currently, the President. The most effective vehicle to bring more efficient care is the employment of evidence-based medicine whenever possible. Evidence-based medicine is dependent on best evidence, and best evidence is generated from prospective trials. To evaluate current state of evidence based practice in pediatric surgery we reviewed the literature for trials conducted in our field the past 10 years. All randomized controlled trials from January 1999 through December 2009 published in the English literature were identified through a literature search using PubMed (www.pubmed.com). We included only those in pediatric general surgery excluding transplant, oncology, and the other nongeneral subspecialties. The search criteria produced 56 manuscripts, of which 51 described appropriate randomization techniques. A definitive trial design with a sample size calculation was utilized in only 19 studies (34%). A statistically significant difference between treatment arms was identified in 29 of the 56 (52%) trials. There were 26 different journals of publication, with the Journal of Pediatric Surgery being most common (20) followed by Pediatric Surgery International (7). The combined total publications from January 1999 through December 2009 for the 26 journals these randomized trials represent 0.04% of all publications. Appendicitis was the most common condition that was studied (n = 10) followed by pyloric stenosis (n = 4). Trials originated in 19 different countries led by the United States (28%), United Kingdom (14%), and Turkey (12%). There was a generally progressive increase in published trials from 1999 to 2009, however, the percentage of prospective articles published in pediatric surgery was similar to a previous review published in 1999. The current state of evidence-based surgery in pediatric surgery has

  3. Reviewing current knowledge in snatch performance and technique: the need for future directions in applied research.

    Science.gov (United States)

    Ho, Lester K W; Lorenzen, Christian; Wilson, Cameron J; Saunders, John E; Williams, Morgan D

    2014-02-01

    This is a review of current research trends in weightlifting literature relating to the understanding of technique and its role in successful snatch performance. Reference to the world records in the snatch from the 1960s onwards indicates little progress across all weight categories. With such mediocre advances in performance at the International level, there is a need to better understand how snatch technique can improve performance even if only by a small margin. Methods of data acquisition for technical analysis of the snatch have involved mostly 2-dimensional barbell and joint kinematics. Although key variables which play a role in the successful outcome of a snatch lift have been heavily investigated, few studies have combined variables relating both the barbell and the weightlifter in their analyses. This suggests the need for a more detailed approach integrating both barbell-related and weightlifter-related data to enhance understanding of the mechanics of a successful lift. Currently, with the aid of technical advances in motion analysis, data acquisition, and methods of analysis, a more accurate representation of the movement can be provided. Better ways of understanding the key characteristics of technique in the snatch could provide the opportunity for more effective individualized feedback from the coach to the athlete, which should in turn lead to improved performance in competition.

  4. Profiling of the injected charge drift current transients by cross-sectional scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Gaubas, E., E-mail: eugenijus.gaubas@ff.vu.lt; Ceponis, T.; Pavlov, J.; Baskevicius, A. [Institute of Applied Research, Vilnius University, Sauletekio av. 9-III, LT-10222 Vilnius (Lithuania)

    2014-02-07

    The electric field distribution and charge drift currents in Si particle detectors are analyzed. Profiling of the injected charge drift current transients has been implemented by varying charge injection position within a cross-sectional boundary of the particle detector. The obtained profiles of the induction current density and duration of the injected charge drift pulses fit well the simulated current variations. Induction current transients have been interpreted by different stages of the bipolar and monopolar drift of the injected carriers. Profiles of the injected charge current transients registered in the non-irradiated and neutron irradiated Si diodes are compared. It has been shown that the mixed regime of the competing processes of drift, recombination, and diffusion appears in the measured current profiles on the irradiated samples. The impact of the avalanche effects can be ignored based on the investigations presented. It has been shown that even a simplified dynamic model enabled us to reproduce the main features of the profiled transients of induced charge drift current.

  5. Profiling of the injected charge drift current transients by cross-sectional scanning technique

    Science.gov (United States)

    Gaubas, E.; Ceponis, T.; Pavlov, J.; Baskevicius, A.

    2014-02-01

    The electric field distribution and charge drift currents in Si particle detectors are analyzed. Profiling of the injected charge drift current transients has been implemented by varying charge injection position within a cross-sectional boundary of the particle detector. The obtained profiles of the induction current density and duration of the injected charge drift pulses fit well the simulated current variations. Induction current transients have been interpreted by different stages of the bipolar and monopolar drift of the injected carriers. Profiles of the injected charge current transients registered in the non-irradiated and neutron irradiated Si diodes are compared. It has been shown that the mixed regime of the competing processes of drift, recombination, and diffusion appears in the measured current profiles on the irradiated samples. The impact of the avalanche effects can be ignored based on the investigations presented. It has been shown that even a simplified dynamic model enabled us to reproduce the main features of the profiled transients of induced charge drift current.

  6. A 540-[Formula: see text] Duty Controlled RSSI With Current Reusing Technique for Human Body Communication.

    Science.gov (United States)

    Jang, Jaeeun; Lee, Yongsu; Cho, Hyunwoo; Yoo, Hoi-Jun

    2016-08-01

    An ultra-low-power duty controlled received signal strength indicator (RSSI) is implemented for human body communication (HBC) in 180 nm CMOS technology under 1.5 V supply. The proposed RSSI adopted 3 following key features for low-power consumption; 1) current reusing technique (CR-RSSI) with replica bias circuit and calibration unit, 2) duty controller, and 3) reconfigurable gm-boosting LNA. The CR-RSSI utilizes stacked amplifier-rectifier-cell (AR-cell) to reuse the supply current of each blocks. As a result, the power consumption becomes 540 [Formula: see text] with +/-2 dB accuracy and 75 dB dynamic range. The replica bias circuit and calibration unit are adopted to increase the reliability of CR-RSSI. In addition, the duty controller turns off the RSSI when it is not required, and this function leads 70% power reduction. At last, the gm-boosting reconfigurable LNA can adaptively vary its noise and linearity performance with respect to input signal strength. Fro current reusing technique m this feature, we achieve 62% power reduction in the LNA. Thanks to these schemes, compared to the previous works, we can save 70% of power in RSSI and LNA.

  7. Overview of Alternative Bunching and Current-shaping Techniques for Low-Energy Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Piot, Philippe [Northern Illinois U.

    2015-12-01

    Techniques to bunch or shape an electron beam at low energies (E <15 MeV) have important implications toward the realization of table-top radiation sources [1] or to the design of compact multi-user free-electron lasers[2]. This paper provides an overview of alternative methods recently developed including techniques such as wakefield-based bunching, space-charge-driven microbunching via wave-breaking [3], ab-initio shaping of the electron-emission process [4], and phase space exchangers. Practical applications of some of these methods to foreseen free-electron-laser configurations are also briefly discussed [5].

  8. An overview of MR arthrography with emphasis on the current technique and applicational hints and tips

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Guelden [Department of Radiology, Faculty of Medicine, Ankara University, Samanpazari, 06100 Ankara (Turkey)]. E-mail: gsahin@medicine.ankara.edu.tr; Demirtas, Mehmet [Department of Hand Surgery, Faculty of Medicine, Ankara University, Samanpazari, 06100 Ankara (Turkey)

    2006-06-15

    Magnetic resonance (MR) arthrography has been investigated in every major peripheral joint of the body, and has been proven to be effective in determining the integrity of intraarticular ligamentous and fibrocartilaginous structures and in the detection or assessment of osteochondral lesions and loose bodies in selected cases. Several methods could be used to create arthrogram effect during MR imaging, however, direct MR arthrography using diluted gadolinium as the contrast agent is the most commonly used technique and is the most reliable of all. MR arthrography is useful for demonstrating labrocapsular-ligamentous abnormalities and distinguishing partial thickness rotator cuff tears from focal full thickness tears in the shoulder, identifying or excluding recurrent tears following meniscal operations in the knee, demonstrating perforations of the triangular fibrocartilage complex (TFCC) and ligaments in the wrist, showing labral tears in the hip, diagnosing ligament tears in the ankle and identifying osteochondral lesions or loose bodies in any of the aforementioned joints. In this article, an overview of techniques of MR arthrography is provided with emphasis on direct MR arthrography using diluted gadolinium as the contrast agent. The current applications of the technique in major peripheral joints are reviewed, with emphasis given to the shoulder joint where the role of this technique has become well established.

  9. Current techniques and strategies for anesthesia in patients undergoing peripheral bypass surgery.

    Science.gov (United States)

    Bouman, E; Dortangs, E; Buhre, W; Gramke, H F

    2014-04-01

    Peripheral arterial disease is an illness with a high prevalence in Europe and North America. The disease is associated with a significant impact on quality of life. Despite advanced medical and endovascular treatments, surgery is often indicated to prevent the consequences of ischemic injury. Usually, these patients do have significant comorbidities resulting in an increased risk for anesthesia-related complications. While general anesthesia is commonly used for the majority of the patients, local and regional anesthesia (RA) offer several possible advantages such as stable cardiovascular hemodynamic perioperative course, improved postoperative pain relief and prevention of chronic postsurgical pain syndromes. This review will discuss perioperative management, available evidence regarding general anesthesia and various regional anesthetic techniques for peripheral vascular surgery, and the current advises regarding anticoagulants and RA. No definitive conclusions can be drawn from the existing literature with respect to superiority of general or neuraxial anesthesia or even RA. Maybe the profits lie in the combination of techniques, a strategy, to overcome the risks of one and use the benefits of the other technique. From circumstantial evidence, it is most likely that the experience of the anesthetic and surgical team is one of the major determinants of perioperative complications independent from the individual anesthesia technique.

  10. PIE: A Dynamic Failure-Based Technique

    Science.gov (United States)

    Voas, Jeffrey M.

    1990-01-01

    This paper presents a dynamic technique for statistically estimating three program characteristics that affect a program's computational behavior: (1) the probability that a particular section of a program is executed, (2) the probability that the particular section affects the data state, and (3) the probability that a data state produced by that section has an effect on program output. These three characteristics can be used to predict whether faults are likely to be uncovered by software testing. Index Terms: Software testing, data state, fault, failure, testability. 1 Introduction

  11. Current techniques in acid-chloride corrosion control and monitoring at The Geysers

    Energy Technology Data Exchange (ETDEWEB)

    Hirtz, Paul; Buck, Cliff; Kunzman, Russell

    1991-01-01

    Acid chloride corrosion of geothermal well casings, production piping and power plant equipment has resulted in costly corrosion damage, frequent curtailments of power plants and the permanent shut-in of wells in certain areas of The Geysers. Techniques have been developed to mitigate these corrosion problems, allowing continued production of steam from high chloride wells with minimal impact on production and power generation facilities.The optimization of water and caustic steam scrubbing, steam/liquid separation and process fluid chemistry has led to effective and reliable corrosion mitigation systems currently in routine use at The Geysers. When properly operated, these systems can yield steam purities equal to or greater than those encountered in areas of The Geysers where chloride corrosion is not a problem. Developments in corrosion monitoring techniques, steam sampling and analytical methodologies for trace impurities, and computer modeling of the fluid chemistry has been instrumental in the success of this technology.

  12. Comparison of Vibration-Based Damage Assessment Techniques

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Rytter, A.

    1995-01-01

    Three different vibration-based damage assessment techniques have been compared. One of the techniques uses the ratios between changes in experimentally and theoretically estimated natural frequencies, respectively, to locate a damage. The second technique relies on updating of a finite element m...

  13. Thickness measurement of multi-layer conductive coatings using multifrequency eddy current techniques

    Science.gov (United States)

    Zhang, Dejun; Yu, Yating; Lai, Chao; Tian, Guiyun

    2016-07-01

    To ensure the key structural performance in high-temperature and high-stress environments, thermal barrier coatings (TBCs) are often adopted in engineering. The thickness of these multi-layer conductive coatings is an important quality indicator. In order to measure the thickness of multi-layer conductive coatings, a new measurement approach is presented using eddy current testing techniques, and then, an inversion algorithm is proposed and proved efficient and applicable, of which the maximum experimental relative error is within 10%. Therefore, the new approach can be effectively applied to thickness measurement of multi-layer conductive coatings such as TBCs.

  14. Investigation of drain current transient behavior in SLS TFTs with the DLTS technique

    Energy Technology Data Exchange (ETDEWEB)

    Exarchos, M A [National and Kapodistrian University of Athens, Physics Department, Solid State Physics Section, Athens 15784 (Greece); Papaioannou, G J [National and Kapodistrian University of Athens, Physics Department, Solid State Physics Section, Athens 15784 (Greece); Kouvatsos, D N [N.C.S.R. Demokritos, Institute of Microelecronics, Athens 15310 (Greece); Voutsas, A T [L.C.D. Process Technology Laboratory, SHARP Labs of America, Inc., Washington 98607 (United States)

    2005-01-01

    In this work, the study of drain current overshoot transients of thin film transistors (TFTs) fabricated by excimer laser sequential lateral solidification (ELA SLS) process is presented. Drain current transient behavior, is ascribed to carrier capture/emission processes within the transistors' Si body, and represents complex mechanisms differently responding at dark and under illumination conditions. Additionally, the thickness of the Si body film, which is an important parameter for the material structure evaluation, ranged from 30 nm to 100 nm. The results were stemmed by deep level transient spectroscopy (DLTS) technique and measurements were conducted within the temperature interval of 200 K to 400 K. The impact of illumination, contributes mainly at lower temperatures through electron-hole generation processes, compensating though carrier freeze-out phenomena.

  15. Investigation of drain current transient behavior in SLS TFTs with the DLTS technique

    Science.gov (United States)

    Exarchos, M. A.; Papaioannou, G. J.; Kouvatsos, D. N.; Voutsas, A. T.

    2005-01-01

    In this work, the study of drain current overshoot transients of thin film transistors (TFTs) fabricated by excimer laser sequential lateral solidification (ELA SLS) process is presented. Drain current transient behavior, is ascribed to carrier capture/emission processes within the transistors' Si body, and represents complex mechanisms differently responding at dark and under illumination conditions. Additionally, the thickness of the Si body film, which is an important parameter for the material structure evaluation, ranged from 30 nm to 100 nm. The results were stemmed by deep level transient spectroscopy (DLTS) technique and measurements were conducted within the temperature interval of 200 K to 400 K. The impact of illumination, contributes mainly at lower temperatures through electron-hole generation processes, compensating though carrier freeze-out phenomena.

  16. Diagnosis of Dengue Infection Using Conventional and Biosensor Based Techniques

    Directory of Open Access Journals (Sweden)

    Om Parkash

    2015-10-01

    Full Text Available Dengue is an arthropod-borne viral disease caused by four antigenically different serotypes of dengue virus. This disease is considered as a major public health concern around the world. Currently, there is no licensed vaccine or antiviral drug available for the prevention and treatment of dengue disease. Moreover, clinical features of dengue are indistinguishable from other infectious diseases such as malaria, chikungunya, rickettsia and leptospira. Therefore, prompt and accurate laboratory diagnostic test is urgently required for disease confirmation and patient triage. The traditional diagnostic techniques for the dengue virus are viral detection in cell culture, serological testing, and RNA amplification using reverse transcriptase PCR. This paper discusses the conventional laboratory methods used for the diagnosis of dengue during the acute and convalescent phase and highlights the advantages and limitations of these routine laboratory tests. Subsequently, the biosensor based assays developed using various transducers for the detection of dengue are also reviewed.

  17. The base line problem in DLTS technique

    OpenAIRE

    G. Couturier; Thabti, A.; Barrière, A.S.

    1989-01-01

    This paper describes a solution to suppress the base line problem in DLTS spectroscopy using a lock-in amplifier. The method has been used to characterize deep levels in a GaAs Schottky diode. Comparison with the classical method based on the use of a capacitance meter in the differential mode is established. The electric field dependence of the DLTS signal in a weakly doped semiconductor is also reported and proves the efficiency of the method. Finally, the data process is discussed.

  18. Risk based technique for improving technical specifications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I. S.; Jae, M. S.; Kim, B. S.; Hwang, S. W.; Kang, K. M.; Park, S. S.; Yu, Y. S. [Hanyang Univ., Seoul (Korea, Republic of)

    2001-03-15

    The objective of this study is to develop the systematic guidance for reviewing the documents associated with the changes of technical specifications. The work done in this fiscal year is the following : surveys in TS requirements, TS improvements and TS regulations in foreign countries as well as Korea, surveys on the state-of-the-art of RITSs and their use in Korea, development of a decision-making framework for both the licensee and the regulation agency, description of risk measures, assessment methodology on STI/AOT, and adverse effects caused by periodic maintenance, which are explained in appendix. The results of this study might contribute to enhancing the quality of the current technical specifications and contribute to preparing the risk informed regulation program using the decision-making framework developed in this study.

  19. Cloud-Based Mobile Video Streaming Techniques

    Directory of Open Access Journals (Sweden)

    Saurabh Goel,

    2013-03-01

    Full Text Available Reasoning processing is changing the landscape of the electronic digital multi-media market by movingthe end customers concentrate from possession of video to buying entry to them in the form of on-demanddelivery solutions. At the identical time, the cloud is used to collect possessed video pathway and formway out that assist viewers to find a whole new variety of multi-media. Cellular devices are a key carowner of this change, due to their natural mobilityand exclusively high transmission rate among endcustomers. This document investigates cloud centered video streaming methods particularly from themobile viewpoint. The qualitative part of the research contains explanations of current video developmentmethods, streaming methods and third celebration cloud centered streaming solutions for different mobilewhich shows my realistic work relevant to streamingmethods with RTMP protocols family and solutionsfor iPhone, Android, Smart mobile phones, Window and BalackBerry phones etc.

  20. Technique for the comparison of light spectra from natural and laboratory generated lightning current arcs

    Science.gov (United States)

    Mitchard, D.; Clark, D.; Carr, D.; Haddad, A.

    2016-08-01

    A technique was developed for the comparison of observed emission spectra from lightning current arcs generated through self-breakdown in air and the use of two types of initiation wire, aluminum bronze and nichrome, against previously published spectra of natural lightning events. A spectrograph system was used in which the wavelength of light emitted by the lightning arc was analyzed to derive elemental interactions. A lightning impulse of up to 100 kA was applied to a two hemispherical tungsten electrode configuration which allowed the effect of the lightning current and lightning arc length to be investigated. A natural lightning reference spectrum was reconstructed from literature, and generated lightning spectra were obtained from self-breakdown across a 14.0 mm air gap and triggered along initiation wires of length up to 72.4 mm. A comparison of the spectra showed that the generated lightning arc induced via self-breakdown produced a very similar spectrum to that of natural lightning, with the addition of only a few lines from the tungsten electrodes. A comparison of the results from the aluminum bronze initiation wire showed several more lines, whereas results from the nichrome initiation wire differed greatly across large parts of the spectrum. This work highlights the potential use for spectrographic techniques in the study of lightning interactions with surrounding media and materials, and in natural phenomena such as recently observed ball lightning.

  1. Technique for the comparison of light spectra from natural and laboratory generated lightning current arcs

    Energy Technology Data Exchange (ETDEWEB)

    Mitchard, D., E-mail: mitcharddr@cardiff.ac.uk; Clark, D.; Carr, D.; Haddad, A. [Morgan-Botti Lightning Laboratory, Advanced High Voltage Research Centre, School of Engineering, Cardiff University, CF24 3AA Wales (United Kingdom)

    2016-08-29

    A technique was developed for the comparison of observed emission spectra from lightning current arcs generated through self-breakdown in air and the use of two types of initiation wire, aluminum bronze and nichrome, against previously published spectra of natural lightning events. A spectrograph system was used in which the wavelength of light emitted by the lightning arc was analyzed to derive elemental interactions. A lightning impulse of up to 100 kA was applied to a two hemispherical tungsten electrode configuration which allowed the effect of the lightning current and lightning arc length to be investigated. A natural lightning reference spectrum was reconstructed from literature, and generated lightning spectra were obtained from self-breakdown across a 14.0 mm air gap and triggered along initiation wires of length up to 72.4 mm. A comparison of the spectra showed that the generated lightning arc induced via self-breakdown produced a very similar spectrum to that of natural lightning, with the addition of only a few lines from the tungsten electrodes. A comparison of the results from the aluminum bronze initiation wire showed several more lines, whereas results from the nichrome initiation wire differed greatly across large parts of the spectrum. This work highlights the potential use for spectrographic techniques in the study of lightning interactions with surrounding media and materials, and in natural phenomena such as recently observed ball lightning.

  2. Novel Method for Sizing Metallic Bottom Crack Depth Using Multi-frequency Alternating Current Potential Drop Technique

    Directory of Open Access Journals (Sweden)

    Li Yuting

    2015-10-01

    Full Text Available Potential drop techniques are of two types: the direct current potential drop (DCPD technique and alternating current potential drop (ACPD technique, and both of them are used in nondestructive testing. ACPD, as a kind of valid method in sizing metal cracks, has been applied to evaluate metal structures. However, our review of most available approaches revealed that some improvements can be done in measuring depth of metal bottom crack by means of ACPD, such as accuracy and sensitivity of shallow crack. This paper studied a novel method which utilized the slope of voltage ratio-frequency curve to solve bottom crack depth by using a simple mathematic equation based on finite element analysis. It is found that voltage ratio varies linearly with frequency in the range of 5-15 Hz; this range is slightly higher than the equivalent frequency and lower than semi-permeable frequency. Simulation and experiment show that the novel method can measure the bottom crack depth accurately.

  3. An Authentication Technique Based on Classification

    Institute of Scientific and Technical Information of China (English)

    李钢; 杨杰

    2004-01-01

    We present a novel watermarking approach based on classification for authentication, in which a watermark is embedded into the host image. When the marked image is modified, the extracted watermark is also different to the original watermark, and different kinds of modification lead to different extracted watermarks. In this paper, different kinds of modification are considered as classes, and we used classification algorithm to recognize the modifications with high probability. Simulation results show that the proposed method is potential and effective.

  4. Currents trends in the application of IBA techniques to air pollution source fingerprinting and source apportionment

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, David; Stelcer, Ed.; Atanacio, Armand; Crawford, Jagoda [Australian Nuclear Science and Technology Organisation, Kirrawee DC (Australia)

    2013-07-01

    Full text: IBA techniques have been used for many years to characterise fine particle air pollution. This is not new the techniques are well established. Typically 2-3 MeV protons are used to bombard thin filter papers and up to four simultaneous techniques like PIXE, PIGE, RBS and ERDA will be applied to obtain (μg/g) concentrations for elements from hydrogen to lead. Generally low volume samplers are used to sample between 20-30 m{sup 3} of air over a 24 hour period, this together with IBA's sensitivity means that concentrations down to 1 ng/m{sup 3} of air sampled can be readily achieved with only a few minutes of proton irradiation. With these short irradiation times and low sensitivities for a broad range of elements in the periodic table, large numbers of samples can be obtained and analysed very quickly and easily. At ANSTO we have used IBA methods to acquire a database of over 50,000 filters from 85 different sites through Australia and Asia, each filter has been analysed for more than 21 different chemical species. Large databases extending over many years means that modern statistical techniques like positive matrix factorisation (PMF) can be used to define well characterised source fingerprints and source contributions for a range of different fine particle air pollutants. In this paper we will discuss these PMF techniques and show how they identify both natural sources like sea spray and windblown soils as well as anthropogenic sources like automobiles, biomass burning, coal-fired power stations and industrial emissions. These data are particularly useful for Governments, EPA's and managers of pollution to better understanding pollution sources and their relative contributions and hence to better manage air pollution. Current trends are to take these IBA and PMF techniques a step further and to combine them with wind speed and back trajectory data to better pin point and identify emission sources. We show how this is now being applied on both

  5. Huffman-based code compression techniques for embedded processors

    KAUST Repository

    Bonny, Mohamed Talal

    2010-09-01

    The size of embedded software is increasing at a rapid pace. It is often challenging and time consuming to fit an amount of required software functionality within a given hardware resource budget. Code compression is a means to alleviate the problem by providing substantial savings in terms of code size. In this article we introduce a novel and efficient hardware-supported compression technique that is based on Huffman Coding. Our technique reduces the size of the generated decoding table, which takes a large portion of the memory. It combines our previous techniques, Instruction Splitting Technique and Instruction Re-encoding Technique into new one called Combined Compression Technique to improve the final compression ratio by taking advantage of both previous techniques. The instruction Splitting Technique is instruction set architecture (ISA)-independent. It splits the instructions into portions of varying size (called patterns) before Huffman coding is applied. This technique improves the final compression ratio by more than 20% compared to other known schemes based on Huffman Coding. The average compression ratios achieved using this technique are 48% and 50% for ARM and MIPS, respectively. The Instruction Re-encoding Technique is ISA-dependent. It investigates the benefits of reencoding unused bits (we call them reencodable bits) in the instruction format for a specific application to improve the compression ratio. Reencoding those bits can reduce the size of decoding tables by up to 40%. Using this technique, we improve the final compression ratios in comparison to the first technique to 46% and 45% for ARM and MIPS, respectively (including all overhead that incurs). The Combined Compression Technique improves the compression ratio to 45% and 42% for ARM and MIPS, respectively. In our compression technique, we have conducted evaluations using a representative set of applications and we have applied each technique to two major embedded processor architectures

  6. FDI and Accommodation Using NN Based Techniques

    Science.gov (United States)

    Garcia, Ramon Ferreiro; de Miguel Catoira, Alberto; Sanz, Beatriz Ferreiro

    Massive application of dynamic backpropagation neural networks is used on closed loop control FDI (fault detection and isolation) tasks. The process dynamics is mapped by means of a trained backpropagation NN to be applied on residual generation. Process supervision is then applied to discriminate faults on process sensors, and process plant parameters. A rule based expert system is used to implement the decision making task and the corresponding solution in terms of faults accommodation and/or reconfiguration. Results show an efficient and robust FDI system which could be used as the core of an SCADA or alternatively as a complement supervision tool operating in parallel with the SCADA when applied on a heat exchanger.

  7. Speed Control Analysis of Brushless DC Motor Based on Maximum Amplitude DC Current Feedback

    Directory of Open Access Journals (Sweden)

    Hassan M.A.A.

    2014-07-01

    Full Text Available This paper describes an approach to develop accurate and simple current controlled modulation technique for brushless DC (BLDC motor drive. The approach is applied to control phase current based on generation of quasi-square wave current by using only one current controller for the three phases. Unlike the vector control method which is complicated to be implemented, this simple current modulation technique presents advantages such as phase currents are kept in balance and the current is controlled through only one dc signal which represent maximum amplitude value of trapezoidal current (Imax. This technique is performed with Proportional Integral (PI control algorithm and triangular carrier comparison method to generate Pulse Width Modulation (PWM signal. In addition, the PI speed controller is incorporated with the current controller to perform desirable speed operation of non-overshoot response. The performance and functionality of the BLDC motor driver are verified via simulation by using MATLAB/SIMULINK. The simulation results show the developed control system performs desirable speed operation of non-overshoot and good current waveforms.

  8. Segmentation of Color Images Based on Different Segmentation Techniques

    Directory of Open Access Journals (Sweden)

    Purnashti Bhosale

    2013-03-01

    Full Text Available In this paper, we propose an Color image segmentation algorithm based on different segmentation techniques. We recognize the background objects such as the sky, ground, and trees etc based on the color and texture information using various methods of segmentation. The study of segmentation techniques by using different threshold methods such as global and local techniques and they are compared with one another so as to choose the best technique for threshold segmentation. Further segmentation is done by using clustering method and Graph cut method to improve the results of segmentation.

  9. Earthquake Analysis of Structure by Base Isolation Technique in SAP

    OpenAIRE

    T. Subramani; J. Jothi

    2014-01-01

    This paper presents an overview of the present state of base isolation techniques with special emphasis and a brief on other techniques developed world over for mitigating earthquake forces on the structures. The dynamic analysis procedure for isolated structures is briefly explained. The provisions of FEMA 450 for base isolated structures are highlighted. The effects of base isolation on structures located on soft soils and near active faults are given in brief. Simple case s...

  10. Ohmic scaling based on current diffusive ballooning mode

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Masatoshi; Itoh, Sanae [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics; Fukuyama, Atsushi; Itoh, Kimitaka

    1996-01-01

    Based on the anomalous transport model due to current diffusive ballooning mode turbulence, the global energy confinement time in a tokamak with Ohmic heating is theoretically studied. Relations to empirical scaling laws are also discussed. (author)

  11. Robot-assisted laparoscopic partial nephrectomy: Current review of the technique and literature

    Directory of Open Access Journals (Sweden)

    Singh Iqbal

    2009-01-01

    Full Text Available Aim: To visit the operative technique and to review the current published English literature on the technique, and outcomes following robot-assisted laparoscopic partial nephrectomy (RPN. Materials and Methods: We searched the published English literature and the PubMed (TM for published series of ′robotic partial nephrectomy′ (RPN using the keywords; robot, robot-assisted laparoscopic partial nephrectomy, laparoscopic partial nephrectomy, partial nephrectomy and laparoscopic surgery. Results: The search yielded 15 major selected series of ′robotic partial nephrectomy′; these were reviewed, tracked and analysed in order to determine the current status and role of RPN in the management of early renal neoplasm(s, as a minimally invasive surgical alternative to open partial nephrectomy. A review of the initial peri-operative outcome of the 350 cases of select series of RPN reported in published English literature revealed a mean operating time, warm ischemia time, estimated blood loss and hospital stay, of 191 minutes, 25 minutes, 162 ml and 2.95 days, respectively. The overall computed mean complication rate of RPN in the present select series was about 7.4%. Conclusions: RPN is a safe, feasible and effective minimally invasive surgical alternative to laparoscopic partial nephrectomy for early stage (T 1 renal neoplasm(s. It has acceptable initial renal functional outcomes without the increased risk of major complications in experienced hands. Prospective randomised, controlled, comparative clinical trials with laparoscopic partial nephrectomy (LPN are the need of the day. While the initial oncological outcomes of RPN appear to be favourable, long-term data is awaited.

  12. Technology-based suicide prevention: current applications and future directions.

    Science.gov (United States)

    Luxton, David D; June, Jennifer D; Kinn, Julie T

    2011-01-01

    This review reports on current and emerging technologies for suicide prevention. Technology-based programs discussed include interactive educational and social networking Web sites, e-mail outreach, and programs that use mobile devices and texting. We describe innovative applications such as virtual worlds, gaming, and text analysis that are currently being developed and applied to suicide prevention and outreach programs. We also discuss the benefits and limitations of technology-based applications and discuss future directions for their use.

  13. Additive Manufacturing Techniques in Prosthodontics: Where Do We Currently Stand? A Critical Review.

    Science.gov (United States)

    Alharbi, Nawal; Wismeijer, Daniel; Osman, Reham B

    The aim of this article was to critically review the current application of additive manufacturing (AM)/3D-printing techniques in prosthodontics and to highlight the influence of various technical factors involved in different AM technologies. A standard approach of searching MEDLINE, EMBASE, and Google Scholar databases was followed. The following search terms were used: (Prosth* OR Restoration) AND (Prototype OR Additive Manufacture* OR Compute* OR 3D-print* OR CAD/CAM) AND (Dentistry OR Dental). Hand searching the reference lists of the included articles and personal connections revealed additional relevant articles. Selection criteria were any article written in English and reporting on the application of AM in prosthodontics from 1990 to February 2016. From a total of 4,290 articles identified, 33 were seen as relevant. Of these, 3 were narrative reviews, 18 were in vitro studies, and 12 were clinical in vivo studies. Different AM technologies are applied in prosthodontics, directly and indirectly for the fabrication of fixed metal copings, metal frameworks for removable partial dentures, and plastic mock-ups and resin patterns for further conventional metal castings. Technical factors involved in different AM techniques influence the overall quality, the mechanical properties of the printed parts, and the total cost and manufacturing time. AM is promising and offers new possibilities in the field of prosthodontics, though its application is still limited. An understanding of these limitations and of developments in material science is crucial prior to considering AM as an acceptable method for the fabrication of dental prostheses.

  14. Minimally invasive surgery of diabetic foot – review of current techniques

    Science.gov (United States)

    I, Botezatu; D, Laptoiu

    2016-01-01

    The term diabetic foot is usually used to indicate advanced foot pathology (complex clinical situations correlating diabetic foot ulcers, diabetic foot infections, Charcot foot, and critical limb ischemia). The early recognition of the etiology of these foot lesions is essential for the therapeutic decision in order to achieve a good functional result. Several surgical procedures involving the foot have been developed in order to promote healing and avoid complications. Traditionally, surgery has been performed in an open way. The literature regarding the performance and efficacy of classical osteotomies and arthrodesis is inconsistent. This can be attributed to several variables, such as differences in patient clinical aspects and the panel of surgical techniques utilized. As with other surgical specialties, fluoroscopic imaging and minimally invasive tools are now being incorporated in these procedures. The use of high speed burrs associated with specialized osteosynthesis implants, offers several advantages over classical techniques. The ability to associate these gestures to complex protocols is beginning to be currently developed. The respect for the soft tissues is considered one of the first advantages. Despite the limited time since they were introduced in clinical practice, functional results seemed to be consistent, supporting the use of this technology. PMID:27974928

  15. Designs and Techniques That Improve the Pullout Strength of Pedicle Screws in Osteoporotic Vertebrae: Current Status

    Directory of Open Access Journals (Sweden)

    Thomas M. Shea

    2014-01-01

    Full Text Available Osteoporosis is a medical condition affecting men and women of different age groups and populations. The compromised bone quality caused by this disease represents an important challenge when a surgical procedure (e.g., spinal fusion is needed after failure of conservative treatments. Different pedicle screw designs and instrumentation techniques have been explored to enhance spinal device fixation in bone of compromised quality. These include alterations of screw thread design, optimization of pilot hole size for non-self-tapping screws, modification of the implant’s trajectory, and bone cement augmentation. While the true benefits and limitations of any procedure may not be realized until they are observed in a clinical setting, axial pullout tests, due in large part to their reproducibility and ease of execution, are commonly used to estimate the device’s effectiveness by quantifying the change in force required to remove the screw from the body. The objective of this investigation is to provide an overview of the different pedicle screw designs and the associated surgical techniques either currently utilized or proposed to improve pullout strength in osteoporotic patients. Mechanical comparisons as well as potential advantages and disadvantages of each consideration are provided herein.

  16. Designs and techniques that improve the pullout strength of pedicle screws in osteoporotic vertebrae: current status.

    Science.gov (United States)

    Shea, Thomas M; Laun, Jake; Gonzalez-Blohm, Sabrina A; Doulgeris, James J; Lee, William E; Aghayev, Kamran; Vrionis, Frank D

    2014-01-01

    Osteoporosis is a medical condition affecting men and women of different age groups and populations. The compromised bone quality caused by this disease represents an important challenge when a surgical procedure (e.g., spinal fusion) is needed after failure of conservative treatments. Different pedicle screw designs and instrumentation techniques have been explored to enhance spinal device fixation in bone of compromised quality. These include alterations of screw thread design, optimization of pilot hole size for non-self-tapping screws, modification of the implant's trajectory, and bone cement augmentation. While the true benefits and limitations of any procedure may not be realized until they are observed in a clinical setting, axial pullout tests, due in large part to their reproducibility and ease of execution, are commonly used to estimate the device's effectiveness by quantifying the change in force required to remove the screw from the body. The objective of this investigation is to provide an overview of the different pedicle screw designs and the associated surgical techniques either currently utilized or proposed to improve pullout strength in osteoporotic patients. Mechanical comparisons as well as potential advantages and disadvantages of each consideration are provided herein.

  17. Pediatric Endoscopic Third Ventriculostomy: A Narrative Review of Current Indications, Techniques and Complications

    Directory of Open Access Journals (Sweden)

    Kaveh Haddadi

    2016-05-01

    Full Text Available Hydrocephalus is a disorder in which excess cerebrospinal fluid (CSF collects in the brain. Possible managements for hydrocephalus contain CSF deviation through ventriculoperitoneal shunt assignment and endoscopic third ventriculostomy. An endoscopic third ventriculostomy has been in trend for the past two decades, as a tool in the field of the neurosurgery, for the management of hydrocephalus. Its utility has been confirmed consistently in congenital and acquired aqueductal stenosis, although the outcomes in communicating hydrocephalus and hydrocephalus secondary to other etiologies have not been impressive. It is a relatively harmless technique with the appropriate selection of patients with a low rate of enduring morbidity. Further studies in child should focus on the predictive factors that are specific to the older population. A combination of clinical, radiological, and intraoperative findings may be necessary to plan a clinical prediction rule suitable to this group of patients. The purpose of this review is to describe the current indications, management outcomes, techniques and complications of this method.

  18. Inquiry-Based Stress Reduction Meditation Technique for Teacher Burnout: A Qualitative Study

    Science.gov (United States)

    Schnaider-Levi, Lia; Mitnik, Inbal; Zafrani, Keren; Goldman, Zehavit; Lev-Ari, Shahar

    2017-01-01

    An inquiry-based intervention has been found to have a positive effect on burnout and mental well-being parameters among teachers. The aim of the current study was to qualitatively evaluate the effect of the inquiry-based stress reduction (IBSR) meditation technique on the participants. Semi-structured interviews were conducted before and after…

  19. Inverter-based circuit design techniques for low supply voltages

    CERN Document Server

    Palani, Rakesh Kumar

    2017-01-01

    This book describes intuitive analog design approaches using digital inverters, providing filter architectures and circuit techniques enabling high performance analog circuit design. The authors provide process, supply voltage and temperature (PVT) variation-tolerant design techniques for inverter based circuits. They also discuss various analog design techniques for lower technology nodes and lower power supply, which can be used for designing high performance systems-on-chip.    .

  20. DOCCⅡ-based electronically tunable current-mode biquadratic filters

    Institute of Scientific and Technical Information of China (English)

    Wang Weidong

    2005-01-01

    A complete state variable current-mode biquadratic filter built by duo-output CCⅡ (DOCCⅡ) with variable current gain is presented. All the coefficients of the filter can be independently tuned through the variable current gain factors of the DOCCⅡ. Based on the principles upon which the general biquadratic filter was constructed, a universal electronically tunable current-mode filter is proposed which implements the low-pass, high-pass, band-pass, band-suppress and all-pass second order transfer functions simultaneously. The PSPICE simulations of frequency responses of second-order filter of are also given.

  1. Fed-state gastric media and drug analysis techniques: Current status and points to consider.

    Science.gov (United States)

    Baxevanis, Fotios; Kuiper, Jesse; Fotaki, Nikoletta

    2016-10-01

    Gastric fed state conditions can have a significant effect on drug dissolution and absorption. In vitro dissolution tests with simple aqueous media cannot usually predict drugs' in vivo response, as several factors such as the meal content, the gastric emptying and possible interactions between food and drug formulations can affect drug's pharmacokinetics. Good understanding of the effect of the in vivo fed gastric conditions on the drug is essential for the development of biorelevant dissolution media simulating the gastric environment after the administration of the standard high fat meal proposed by the FDA and the EMA in bioavailability/bioequivalence (BA/BE) studies. The analysis of drugs in fed state media can be quite challenging as most analytical protocols currently employed are time consuming and labour intensive. In this review, an overview of the in vivo gastric conditions and the biorelevant media used for their in vitro simulation are described. Furthermore an analysis of the physicochemical properties of the drugs and the formulations related to food effect is given. In terms of drug analysis, the protocols currently used for the fed state media sample treatment and analysis and the analytical challenges and needs emerging for more efficient and time saving techniques for a broad spectrum of compounds are being discussed.

  2. Mycoplasma pneumoniae: Current knowledge on nucleic acid amplification techniques and serological diagnostics

    Directory of Open Access Journals (Sweden)

    Katherine eLoens

    2016-03-01

    Full Text Available Mycoplasma pneumoniae (M. pneumoniae belongs to the class Mollicutes and has been recognized as a common cause of respiratory tract infections (RTIs, including community-acquired pneumonia (CAP, that occur worldwide and in all age groups. In addition, M. pneumoniae can simultaneously or sequentially lead to damage in the nervous system and has been associated with a wide variety of other acute and chronic diseases. During the past 10 years, the proportion of LRTI in children and adults, associated with M. pneumoniae infection has ranged from 0% to more than 50%. This variation is due to the age and the geographic location of the population examined but also due to the diagnostic methods used. The true role of M. pneumoniae in RTIs remains a challenge given the many limitations and lack of standardization of the applied diagnostic tool in most cases, with resultant wide variations in data from different studies.Correct and rapid diagnosis and/or management of M. pneumoniae infections is, however, critical to initiate appropriate antibiotic treatment and is nowadays usually done by PCR and/or serology. Several recent reviews have summarized current methods for the detection and identification of M. pneumoniae. This review will therefore provide a look at the general principles, advantages, diagnostic value, and limitations of the most currently used detection techniques for the etiological diagnosis of a M. pneumoniae infection as they evolve from research to daily practice.

  3. A DEMO relevant fast wave current drive high harmonic antenna exploiting the high impedance technique

    Science.gov (United States)

    Milanesio, D.; Maggiora, R.

    2015-12-01

    Ion Cyclotron (IC) antennas are routinely adopted in most of the existing nuclear fusion experiments, even though their main goal, i.e. to couple high power to the plasma (MW), is often limited by rather severe drawbacks due to high fields on the antenna itself and on the unmatched part of the feeding lines. In addition to the well exploited auxiliary ion heating during the start-up phase, some non-ohmic current drive (CD) at the IC range of frequencies may be explored in view of the DEMO reactor. In this work, we suggest and describe a compact high frequency DEMO relevant antenna, based on the high impedance surfaces concept. High-impedance surfaces are periodic metallic structures (patches) usually displaced on top of a dielectric substrate and grounded by means of vertical posts embedded inside the dielectric, in a mushroom-like shape. These structures present a high impedance, within a given frequency band, such that the image currents are in-phase with the currents of the antenna itself, thus determining a significant efficiency increase. After a general introduction on the properties of high impedance surfaces, we analyze, by means of numerical codes, a dielectric based and a full metal solution optimized to be tested and benchmarked on the FTU experiment fed with generators at 433MHz.

  4. A DEMO relevant fast wave current drive high harmonic antenna exploiting the high impedance technique

    Energy Technology Data Exchange (ETDEWEB)

    Milanesio, D., E-mail: daniele.milanesio@polito.it; Maggiora, R. [Politecnico di Torino, Dipartimento di Elettronica e Telecomunicazioni (DET), Torino (Italy)

    2015-12-10

    Ion Cyclotron (IC) antennas are routinely adopted in most of the existing nuclear fusion experiments, even though their main goal, i.e. to couple high power to the plasma (MW), is often limited by rather severe drawbacks due to high fields on the antenna itself and on the unmatched part of the feeding lines. In addition to the well exploited auxiliary ion heating during the start-up phase, some non-ohmic current drive (CD) at the IC range of frequencies may be explored in view of the DEMO reactor. In this work, we suggest and describe a compact high frequency DEMO relevant antenna, based on the high impedance surfaces concept. High-impedance surfaces are periodic metallic structures (patches) usually displaced on top of a dielectric substrate and grounded by means of vertical posts embedded inside the dielectric, in a mushroom-like shape. These structures present a high impedance, within a given frequency band, such that the image currents are in-phase with the currents of the antenna itself, thus determining a significant efficiency increase. After a general introduction on the properties of high impedance surfaces, we analyze, by means of numerical codes, a dielectric based and a full metal solution optimized to be tested and benchmarked on the FTU experiment fed with generators at 433MHz.

  5. SIMULATION AND IMPLEMENTATION OF CURRENT CONTROL OF BRUSHLESS DC MOTOR BASED ON A COMMON DC SIGNAL

    Directory of Open Access Journals (Sweden)

    J.Karthikeyan

    2010-06-01

    Full Text Available The objective of this project is to build a simple current controlled modulation technique for brushless dc motors. In electric traction and most other applications, a wide range of speed and torque control of the electric motor is required. The dc machine fulfills these requirements, but the dc machine requires constant maintenance. But the brushless permanent magnet motors do not have brushes and so they require less maintenance only. Brushless dc motors are widely used in applications which require wide range of speed and torque control because of its low inertia, fast response, high reliability and maintenance free. This current controlled technique is based on the generation of quasi- square wave currents using only one controller for the three phases. The current control strategy uses a triangular carrier for the power transistors which is simpler and more accuratethan any other options. The advantages of this technique are: a The stator currents are completely characterized by their maximum amplitude , b The three phases are controlled with the same dc component , and then the phase currents are kept at exactly the same magnitude I max, c The dc link current measurement is not required .d phase currents are kept balanced and phase over currents are eliminated.

  6. Fractal-Based Methods and Inverse Problems for Differential Equations: Current State of the Art

    OpenAIRE

    Kunze, Herb E.; Davide La Torre; Franklin Mendivil; Manuel Ruiz Galán; Rachad Zaki

    2014-01-01

    We illustrate, in this short survey, the current state of the art of fractal-based techniques and their application to the solution of inverse problems for ordinary and partial differential equations. We review several methods based on the Collage Theorem and its extensions. We also discuss two innovative applications: the first one is related to a vibrating string model while the second one considers a collage-based approach for solving inverse problems for partial differential equations on ...

  7. Cardiac magnetic source imaging based on current multipole model

    Institute of Scientific and Technical Information of China (English)

    Tang Fa-Kuan; Wang Qian; Hua Ning; Lu Hong; Tang Xue-Zheng; Ma Ping

    2011-01-01

    It is widely accepted that the heart current source can be reduced into a current multipole. By adopting three linear inverse methods, the cardiac magnetic imaging is achieved in this article based on the current multipole model expanded to the first order terms. This magnetic imaging is realized in a reconstruction plane in the centre of human heart, where the current dipole array is employed to represent realistic cardiac current distribution. The current multipole as testing source generates magnetic fields in the measuring plane, serving as inputs of cardiac magnetic inverse problem. In the heart-torso model constructed by boundary element method, the current multipole magnetic field distribution is compared with that in the homogeneous infinite space, and also with the single current dipole magnetic field distribution.Then the minimum-norm least-squares (MNLS) method, the optimal weighted pseuDOInverse method (OWPIM), and the optimal constrained linear inverse method (OCLIM) are selected as the algorithms for inverse computation based on current multipole model innovatively, and the imaging effects of these three inverse methods are compared. Besides,two reconstructing parameters, residual and mean residual, are also discussed, and their trends under MNLS, OWPIM and OCLIM each as a function of SNR are obtained and compared.

  8. Optimization of brushless direct current motor design using an intelligent technique.

    Science.gov (United States)

    Shabanian, Alireza; Tousiwas, Armin Amini Poustchi; Pourmandi, Massoud; Khormali, Aminollah; Ataei, Abdolhay

    2015-07-01

    This paper presents a method for the optimal design of a slotless permanent magnet brushless DC (BLDC) motor with surface mounted magnets using an improved bee algorithm (IBA). The characteristics of the motor are expressed as functions of motor geometries. The objective function is a combination of losses, volume and cost to be minimized simultaneously. This method is based on the capability of swarm-based algorithms in finding the optimal solution. One sample case is used to illustrate the performance of the design approach and optimization technique. The IBA has a better performance and speed of convergence compared with bee algorithm (BA). Simulation results show that the proposed method has a very high/efficient performance.

  9. Current Source Based on H-Bridge Inverter with Output LCL Filter

    Science.gov (United States)

    Blahnik, Vojtech; Talla, Jakub; Peroutka, Zdenek

    2015-09-01

    The paper deals with a control of current source with an LCL output filter. The controlled current source is realized as a single-phase inverter and output LCL filter provides low ripple of output current. However, systems incorporating LCL filters require more complex control strategies and there are several interesting approaches to the control of this type of converter. This paper presents the inverter control algorithm, which combines model based control with a direct current control based on resonant controllers and single-phase vector control. The primary goal is to reduce the current ripple and distortion under required limits and provides fast and precise control of output current. The proposed control technique is verified by measurements on the laboratory model.

  10. Current state of the art of vision based SLAM

    Science.gov (United States)

    Muhammad, Naveed; Fofi, David; Ainouz, Samia

    2009-02-01

    The ability of a robot to localise itself and simultaneously build a map of its environment (Simultaneous Localisation and Mapping or SLAM) is a fundamental characteristic required for autonomous operation of the robot. Vision Sensors are very attractive for application in SLAM because of their rich sensory output and cost effectiveness. Different issues are involved in the problem of vision based SLAM and many different approaches exist in order to solve these issues. This paper gives a classification of state-of-the-art vision based SLAM techniques in terms of (i) imaging systems used for performing SLAM which include single cameras, stereo pairs, multiple camera rigs and catadioptric sensors, (ii) features extracted from the environment in order to perform SLAM which include point features and line/edge features, (iii) initialisation of landmarks which can either be delayed or undelayed, (iv) SLAM techniques used which include Extended Kalman Filtering, Particle Filtering, biologically inspired techniques like RatSLAM, and other techniques like Local Bundle Adjustment, and (v) use of wheel odometry information. The paper also presents the implementation and analysis of stereo pair based EKF SLAM for synthetic data. Results prove the technique to work successfully in the presence of considerable amounts of sensor noise. We believe that state of the art presented in the paper can serve as a basis for future research in the area of vision based SLAM. It will permit further research in the area to be carried out in an efficient and application specific way.

  11. High current gain silicon-based spin transistor

    CERN Document Server

    Dennis, C L; Ensell, G J; Gregg, J F; Thompson, S M

    2003-01-01

    A silicon-based spin transistor of novel operating principle has been demonstrated in which the current gain at room temperature is 1.4 (n-type) and 0.97 (p-type). This high current gain was obtained from a hybrid metal/semiconductor analogue to the bipolar junction transistor which functions by tunnel-injecting carriers from a ferromagnetic emitter into a diffusion driven silicon base and then tunnel-collecting them via a ferromagnetic collector. The switching of the magnetic state of the collector ferromagnet controls the collector efficiency and the current gain. Furthermore, the magnetocurrent, which is determined to be 98% (140%) for p-type (n-type) in -110 Oe, is attributable to the spin-polarized base diffusion current.

  12. Hysteresis current control technique of VSI for compensation of grid-connected unbalanced loads

    DEFF Research Database (Denmark)

    Pouresmaeil, Edris; Akorede, Mudathir Funsho; Montesinos-Miracle, Daniel

    2014-01-01

    The global trends nowadays in the power generation industry are to supplement the electricity production using distributed generation (DG) technologies based on renewable energy resources such as photovoltaic, wind power, etc. However, failure to properly control the operation of distributed energy...... resources as they connect to the exiting power grid could provoke many power quality problems on the grid side. For this reason, due considerations must be given to power generation and safe running before DG units is actually integrated into the power grid. The main aim of this paper is to address the grid...... in the total harmonic distortion of grid currents. © 2012 Springer-Verlag Berlin Heidelberg....

  13. The detection of bulk explosives using nuclear-based techniques

    Energy Technology Data Exchange (ETDEWEB)

    Morgado, R.E.; Gozani, T.; Seher, C.C.

    1988-01-01

    In 1986 we presented a rationale for the detection of bulk explosives based on nuclear techniques that addressed the requirements of civil aviation security in the airport environment. Since then, efforts have intensified to implement a system based on thermal neutron activation (TNA), with new work developing in fast neutron and energetic photon reactions. In this paper we will describe these techniques and present new results from laboratory and airport testing. Based on preliminary results, we contended in our earlier paper that nuclear-based techniques did provide sufficiently penetrating probes and distinguishable detectable reaction products to achieve the FAA operational goals; new data have supported this contention. The status of nuclear-based techniques for the detection of bulk explosives presently under investigation by the US Federal Aviation Administration (FAA) is reviewed. These include thermal neutron activation (TNA), fast neutron activation (FNA), the associated particle technique, nuclear resonance absorption, and photoneutron activation. The results of comprehensive airport testing of the TNA system performed during 1987-88 are summarized. From a technical point of view, nuclear-based techniques now represent the most comprehensive and feasible approach for meeting the operational criteria of detection, false alarms, and throughput. 9 refs., 5 figs., 2 tabs.

  14. Non destructive technique for cracks detection by an eddy current in differential mode for steel frames

    Energy Technology Data Exchange (ETDEWEB)

    Harzalla, S., E-mail: harzallahozil@yahoo.fr; Chabaat, M., E-mail: mchabaat@yahoo.com [Built Environmental Research Laboratory, Civil Engineering Faculty, University of Sciences and Technology Houari Boumediene, B.P. 32 El Alia Bab-Ezzouar, Algiers 16111 (Algeria); Belgacem, F. Bin Muhammad, E-mail: fbmbelgacem@gmail.com [Department of Mathematics, Faculty of Basic Education, PAAET, Al-Aardhia (Kuwait)

    2014-12-10

    In this paper, a nondestructive technique is used as a tool to control cracks and microcracks in materials. A simulation by a numerical approach such as the finite element method is employed to detect cracks and eventually; to study their propagation using a crucial parameter such as the stress intensity factor. This approach has been used in the aircraft industry to control cracks. Besides, it makes it possible to highlight the defects of parts while preserving the integrity of the controlled products. On the other side, it is proven that the reliability of the control of defects gives convincing results for the improvement of the quality and the safety of the material. Eddy current testing (ECT) is a standard technique in industry for the detection of surface breaking flaws in magnetic materials such as steels. In this context, simulation tools can be used to improve the understanding of experimental signals, optimize the design of sensors or evaluate the performance of ECT procedures. CEA-LIST has developed for many years semi-analytical models embedded into the simulation platform CIVA dedicated to non-destructive testing. The developments presented herein address the case of flaws located inside a planar and magnetic medium. Simulation results are obtained through the application of the Volume Integral Method (VIM). When considering the ECT of a single flaw, a system of two differential equations is derived from Maxwell equations. The numerical resolution of the system is carried out using the classical Galerkin variant of the Method of Moments. Besides, a probe response is calculated by application of the Lorentz reciprocity theorem. Finally, the approach itself as well as comparisons between simulation results and measured data are presented.

  15. Current updates on laboratory techniques for the diagnosis of male reproductive failure.

    Science.gov (United States)

    Sikka, Suresh C; Hellstrom, Wayne J G

    2016-01-01

    The incidence of male reproductive failure leading to infertility, whether due to delayed parenthood, environmental issues, genetic factors, drugs, etc., is increasing throughout the world. The diagnosis and prognosis of male subfertility have become a challenge. While the basic semen assessment has been performed for many years, a number of studies question the value of the traditional semen characteristics. This is partly due to inadequate methods and standardization, limited knowledge of technical requirements for quality assurance, and an incomplete understanding of what clinical information a semen assessment can provide. Laboratories currently performing semen and endocrine assessment show great variability. The World Health Organization (WHO) manual for the evaluation of semen has been the core of andrology and fertility evaluation that has helped in further development of this field over many years. These include the physical appearance of the ejaculate, assessments of sperm count, motility, vitality, morphology, and functional aspects of the sperm and semen sample. These tests also include male endocrine profile, biochemical evaluation of the semen, detection of antisperm antibodies in serum, the use of computer-aided sperm analysis (CASA), sperm DNA integrity, and its damage due to oxidative stress. Assisted reproductive techniques (e.g., IVF, ICSI) have shown great success but are too expensive. Further development in this field with newer techniques and extensive training/instructions can improve accuracy and reduce variability, thus maintaining the quality and standards of such an evaluation. There is an urgent need to have standardized training centers and increased awareness in this area of men's health for reproductive success.

  16. Current updates on laboratory techniques for the diagnosis of male reproductive failure

    Directory of Open Access Journals (Sweden)

    Suresh C Sikka

    2016-01-01

    Full Text Available The incidence of male reproductive failure leading to infertility, whether due to delayed parenthood, environmental issues, genetic factors, drugs, etc., is increasing throughout the world. The diagnosis and prognosis of male subfertility have become a challenge. While the basic semen assessment has been performed for many years, a number of studies question the value of the traditional semen characteristics. This is partly due to inadequate methods and standardization, limited knowledge of technical requirements for quality assurance, and an incomplete understanding of what clinical information a semen assessment can provide. Laboratories currently performing semen and endocrine assessment show great variability. The World Health Organization (WHO manual for the evaluation of semen has been the core of andrology and fertility evaluation that has helped in further development of this field over many years. These include the physical appearance of the ejaculate, assessments of sperm count, motility, vitality, morphology, and functional aspects of the sperm and semen sample. These tests also include male endocrine profile, biochemical evaluation of the semen, detection of antisperm antibodies in serum, the use of computer-aided sperm analysis (CASA, sperm DNA integrity, and its damage due to oxidative stress. Assisted reproductive techniques (e.g., IVF, ICSI have shown great success but are too expensive. Further development in this field with newer techniques and extensive training/instructions can improve accuracy and reduce variability, thus maintaining the quality and standards of such an evaluation. There is an urgent need to have standardized training centers and increased awareness in this area of men′s health for reproductive success.

  17. Neuromuscular electrostimulation techniques: historical aspects and current possibilities in treatment of pain and muscle waisting.

    Science.gov (United States)

    Heidland, August; Fazeli, Gholamreza; Klassen, André; Sebekova, Katarina; Hennemann, Hans; Bahner, Udo; Di Iorio, Biagio

    2013-01-01

    Application of electricity for pain treatment dates back to thousands of years BC. The Ancient Egyptians and later the Greeks and Romans recognized that electrical fishes are capable of generating electric shocks for relief of pain. In the 18th and 19th centuries these natural producers of electricity were replaced by man-made electrical devices. This happened in following phases. The first was the application of static electrical currents (called Franklinism), which was produced by a friction generator. Christian Kratzenstein was the first to apply it medically, followed shortly by Benjamin Franklin. The second phase was Galvanism. This method applied a direct electrical current to the skin by chemical means, applied a direct and pulsed electrical current to the skin. In the third phase the electrical current was induced intermittently and in alternate directions (called Faradism). The fourth stage was the use of high frequency currents (called d'Arsonvalisation). The 19th century was the "golden age" of electrotherapy. It was used for countless dental, neurological, psychiatric and gynecological disturbances. However, at beginning of the 20th century electrotherapy fell from grace. It was dismissed as lacking a scientific basis and being used also by quacks and charlatans for unserious aims. Furthermore, the development of effective analgesic drugs decreased the interest in electricity. In the second half of the 20th century electrotherapy underwent a revival. Based on animal experiments and clinical investigations, its neurophysiological mechanisms were elucidated in more details. The pain relieving action of electricity was explained in particular by two main mechanisms: first, segmental inhibition of pain signals to the brain in the dorsal horn of the spinal cord and second, activation of the descending inhibitory pathway with enhanced release of endogenous opioids and other neurochemical compounds (serotonin, noradrenaline, gamma aminobutyric acid (GABA

  18. Current and emerging techniques for contaminant mapping and data visualization at DNAPL sites

    DEFF Research Database (Denmark)

    Wealthall, Gary; Durant, Neal; Grosen, Bernt

    Recent advances in the development of contaminant specific site investigation tools has significantly enhanced our ability to characterize the spatial architecture of DNAPL source zones in both sedimentary and fractured bedrock environments. The application of innovative site characterization...... methods will be discussed in the context of contaminant delineation, remediation design, technology verification and regulatory acceptance. We present a range of site investigation tools, based on the principle of combined lines of evidence and the premise that a single technique is not available to fully...... delineate DNAPL distribution in the subsurface. Key to this strategy is the selection of technologies with multiple scales of measurement and data quality, of which there are two main categories. The first category provides qualitative, dense spatial data, often with higher detection limits over a preset...

  19. A Passive Optical Fiber Current Sensor Based on YIG

    Institute of Scientific and Technical Information of China (English)

    Jing Shao; Wen Liu; Cui-Qing Liu; Duan Xu

    2008-01-01

    A research on passive optical fiber current sensor based on magneto-optical crystal and a new design of light path of the sensor head are presented. Both methods of dual-channel optical detection of the polarization state of the output light and signal processing are proposed. Signal processing can obtain the linear output of the current measurement of the wire more conveniently. Theoretical analysis on the magneto-optical fiber current sensor is given, followed by experiments. After that, further analysis is made according to the results, which leads to clarifying the exiting problems and their placements.

  20. Current phase relation in nanowire based Josephson junctions

    Science.gov (United States)

    Szombati, Daniel; Nadj-Perge, Stevan; Geresdi, Attila; Mourik, Vincent; Zuo, Kun; Woerkom, David; Car, Diana; Bakkers, Erik; Kouwenhoven, Leo

    2015-03-01

    Junctions based on small band-gap nanowires are convenient platform for studying Josephson effect in the presence of strong spin-orbit coupling. As predicted by theory, due to the interplay between strong Zeeman interaction and large spin orbing coupling in these nanowires, the critical current and in particular current phase relation exhibits rich set of features in the presence of external magnetic field and electrostatic gating. We study supercurrent transport through Indium Antimonide nanowires contacted using Niobium-Titanium-Nitride leads using both current and phase bias measurements. Our results provide useful insights into superconductor/semiconductor hybrid systems capable of hosting Majorana fermions, potential building blocks for topological quantum computing.

  1. A low power and low distortion rail-to-rail input/output amplifier using constant current technique

    Science.gov (United States)

    Yan, Liu; Yiqiang, Zhao; Shilin, Zhang; Hongliang, Zhao

    2011-04-01

    A rail-to-rail amplifier with constant transconductance, intended for audio processing, is presented. The constant transconductance is obtained by a constant current technique based on the input differential pairs operating in the weak inversion region. MOSFETs working in the weak inversion region have the advantages of low power and low distortion. The proposed rail-to-rail amplifier, fabricated in a standard 0.35 μm CMOS process, occupies a core die area of 75 × 183 μm2. Measured results show that the maximum power consumption is 85.37 μW with a supply voltage of 3.3 V and the total harmonic distortion level is 1.2% at 2 kHz.

  2. A low power and low distortion rail-to-rail input/output amplifier using constant current technique

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yan; Zhao Yiqiang; Zhang Shilin [School of Electronic Information Engineering, Tianjin University, Tianjin 300072 (China); Zhao Hongliang, E-mail: zhaoyq@tju.edu.cn [School of Physics, Liaoning University, Shenyang 110036 (China)

    2011-04-15

    A rail-to-rail amplifier with constant transconductance, intended for audio processing, is presented. The constant transconductance is obtained by a constant current technique based on the input differential pairs operating in the weak inversion region. MOSFETs working in the weak inversion region have the advantages of low power and low distortion. The proposed rail-to-rail amplifier, fabricated in a standard 0.35 {mu}m CMOS process, occupies a core die area of 75 x 183 {mu}m{sup 2}. Measured results show that the maximum power consumption is 85.37 {mu}W with a supply voltage of 3.3 V and the total harmonic distortion level is 1.2% at 2 kHz. (semiconductor integrated circuits)

  3. Controlling charge current through a DNA based molecular transistor

    Science.gov (United States)

    Behnia, S.; Fathizadeh, S.; Ziaei, J.

    2017-01-01

    Molecular electronics is complementary to silicon-based electronics and may induce electronic functions which are difficult to obtain with conventional technology. We have considered a DNA based molecular transistor and study its transport properties. The appropriate DNA sequence as a central chain in molecular transistor and the functional interval for applied voltages is obtained. I-V characteristic diagram shows the rectifier behavior as well as the negative differential resistance phenomenon of DNA transistor. We have observed the nearly periodic behavior in the current flowing through DNA. It is reported that there is a critical gate voltage for each applied bias which above it, the electrical current is always positive.

  4. SQUID Based Cryogenic Current Comparator for Measurements of the Dark Current of Superconducting Cavities

    CERN Document Server

    Vodel, W; Neubert, R; Nietzsche, S

    2005-01-01

    This contribution presents a LTS-SQUID based Cryogenic Current Comparator (CCC) for detecting dark currents, generated e.g. by superconducting cavities for the upcoming X-FEL project at DESY. To achieve the maximum possible energy the gradients of the superconducting RF cavities should be pushed close to the physical limit of 50 MV/m. The measurement of the undesired field emission of electrons (the so-called dark current) in correlation with the gradient will give a proper value to compare and classify the cavities. The main component of the CCC is a high performance LTS-DC SQUID system which is able to measure extremely low magnetic fields, e.g. caused by the extracted dark current. For this reason the input coil of the SQUID is connected across a special designed toroidal niobium pick-up coil (inner diameter: about 100 mm) for the passing electron beam. A noise limited current resolution of nearly 2 pA/√(Hz) with a measurement bandwidth of up to 70 kHz was achieved without the pick-up coil. Now, ...

  5. Watermarking Digital Images Based on a Content Based Image Retrieval Technique

    CERN Document Server

    Tsolis, Dimitrios K; Papatheodorou, Theodore S

    2008-01-01

    The current work is focusing on the implementation of a robust watermarking algorithm for digital images, which is based on an innovative spread spectrum analysis algorithm for watermark embedding and on a content-based image retrieval technique for watermark detection. The highly robust watermark algorithms are applying "detectable watermarks" for which a detection mechanism checks if the watermark exists or no (a Boolean decision) based on a watermarking key. The problem is that the detection of a watermark in a digital image library containing thousands of images means that the watermark detection algorithm is necessary to apply all the keys to the digital images. This application is non-efficient for very large image databases. On the other hand "readable" watermarks may prove weaker but easier to detect as only the detection mechanism is required. The proposed watermarking algorithm combine's the advantages of both "detectable" and "readable" watermarks. The result is a fast and robust watermarking algor...

  6. Power system stabilizers based on modern control techniques

    Energy Technology Data Exchange (ETDEWEB)

    Malik, O.P.; Chen, G.P.; Zhang, Y.; El-Metwally, K. [Calgary Univ., AB (Canada). Dept. of Electrical and Computer Engineering

    1994-12-31

    Developments in digital technology have made it feasible to develop and implement improved controllers based on sophisticated control techniques. Power system stabilizers based on adaptive control, fuzzy logic and artificial networks are being developed. Each of these control techniques possesses unique features and strengths. In this paper, the relative performance of power systems stabilizers based on adaptive control, fuzzy logic and neural network, both in simulation studies and real time tests on a physical model of a power system, is presented and compared to that of a fixed parameter conventional power system stabilizer. (author) 16 refs., 45 figs., 3 tabs.

  7. An Improved Particle Swarm Optimization Algorithm Based on Ensemble Technique

    Institute of Scientific and Technical Information of China (English)

    SHI Yan; HUANG Cong-ming

    2006-01-01

    An improved particle swarm optimization (PSO) algorithm based on ensemble technique is presented. The algorithm combines some previous best positions (pbest) of the particles to get an ensemble position (Epbest), which is used to replace the global best position (gbest). It is compared with the standard PSO algorithm invented by Kennedy and Eberhart and some improved PSO algorithms based on three different benchmark functions. The simulation results show that the improved PSO based on ensemble technique can get better solutions than the standard PSO and some other improved algorithms under all test cases.

  8. Efficient Plant Supervision Strategy Using NN Based Techniques

    Science.gov (United States)

    Garcia, Ramon Ferreiro; Rolle, Jose Luis Calvo; Castelo, Francisco Javier Perez

    Most of non-linear type one and type two control systems suffers from lack of detectability when model based techniques are applied on FDI (fault detection and isolation) tasks. In general, all types of processes suffer from lack of detectability also due to the ambiguity to discriminate the process, sensors and actuators in order to isolate any given fault. This work deals with a strategy to detect and isolate faults which include massive neural networks based functional approximation procedures associated to recursive rule based techniques applied to a parity space approach.

  9. An Agent Communication Framework Based on XML and SOAP Technique

    Institute of Scientific and Technical Information of China (English)

    李晓瑜

    2009-01-01

    This thesis introducing XML technology and SOAP technology,present an agent communication fi-amework based on XML and SOAP technique,and analyze the principle,architecture,function and benefit of it. At the end, based on KQML communication primitive lan- guages.

  10. Decomposition Techniques and Effective Algorithms in Reliability-Based Optimization

    DEFF Research Database (Denmark)

    Enevoldsen, I.; Sørensen, John Dalsgaard

    1995-01-01

    The common problem of an extensive number of limit state function calculations in the various formulations and applications of reliability-based optimization is treated. It is suggested to use a formulation based on decomposition techniques so the nested two-level optimization problem can be solved...

  11. Data Mining and Neural Network Techniques in Case Based System

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper first puts forward a case-based system framework basedon data mining techniques. Then the paper examines the possibility of using neural n etworks as a method of retrieval in such a case-based system. In this system we propose data mining algorithms to discover case knowledge and other algorithms.

  12. Simulation-based optimization parametric optimization techniques and reinforcement learning

    CERN Document Server

    Gosavi, Abhijit

    2003-01-01

    Simulation-Based Optimization: Parametric Optimization Techniques and Reinforcement Learning introduces the evolving area of simulation-based optimization. The book's objective is two-fold: (1) It examines the mathematical governing principles of simulation-based optimization, thereby providing the reader with the ability to model relevant real-life problems using these techniques. (2) It outlines the computational technology underlying these methods. Taken together these two aspects demonstrate that the mathematical and computational methods discussed in this book do work. Broadly speaking, the book has two parts: (1) parametric (static) optimization and (2) control (dynamic) optimization. Some of the book's special features are: *An accessible introduction to reinforcement learning and parametric-optimization techniques. *A step-by-step description of several algorithms of simulation-based optimization. *A clear and simple introduction to the methodology of neural networks. *A gentle introduction to converg...

  13. Biogeosystem technique as a base of Sustainable Irrigated Agriculture

    Science.gov (United States)

    Batukaev, Abdulmalik

    2016-04-01

    The world water strategy is to be changed because the current imitational gravitational frontal isotropic-continual paradigm of irrigation is not sustainable. This paradigm causes excessive consumption of fresh water - global deficit - up to 4-15 times, adverse effects on soils and landscapes. Current methods of irrigation does not control the water spread throughout the soil continuum. The preferable downward fluxes of irrigation water are forming, up to 70% and more of water supply loses into vadose zone. The moisture of irrigated soil is high, soil loses structure in the process of granulometric fractions flotation decomposition, the stomatal apparatus of plant leaf is fully open, transpiration rate is maximal. We propose the Biogeosystem technique - the transcendental, uncommon and non-imitating methods for Sustainable Natural Resources Management. New paradigm of irrigation is based on the intra-soil pulse discrete method of water supply into the soil continuum by injection in small discrete portions. Individual volume of water is supplied as a vertical cylinder of soil preliminary watering. The cylinder position in soil is at depth form 10 to 30 cm. Diameter of cylinder is 1-2 cm. Within 5-10 min after injection the water spreads from the cylinder of preliminary watering into surrounding soil by capillary, film and vapor transfer. Small amount of water is transferred gravitationally to the depth of 35-40 cm. The soil watering cylinder position in soil profile is at depth of 5-50 cm, diameter of the cylinder is 2-4 cm. Lateral distance between next cylinders along the plant raw is 10-15 cm. The soil carcass which is surrounding the cylinder of non-watered soil remains relatively dry and mechanically stable. After water injection the structure of soil in cylinder restores quickly because of no compression from the stable adjoining volume of soil and soil structure memory. The mean soil thermodynamic water potential of watered zone is -0.2 MPa. At this potential

  14. A Hough Transform based Technique for Text Segmentation

    CERN Document Server

    Saha, Satadal; Nasipuri, Mita; Basu, Dipak Kr

    2010-01-01

    Text segmentation is an inherent part of an OCR system irrespective of the domain of application of it. The OCR system contains a segmentation module where the text lines, words and ultimately the characters must be segmented properly for its successful recognition. The present work implements a Hough transform based technique for line and word segmentation from digitized images. The proposed technique is applied not only on the document image dataset but also on dataset for business card reader system and license plate recognition system. For standardization of the performance of the system the technique is also applied on public domain dataset published in the website by CMATER, Jadavpur University. The document images consist of multi-script printed and hand written text lines with variety in script and line spacing in single document image. The technique performs quite satisfactorily when applied on mobile camera captured business card images with low resolution. The usefulness of the technique is verifie...

  15. Measuring the corrosion rate of steel in concrete – effect of measurement technique, polarisation time and current

    DEFF Research Database (Denmark)

    Nygaard, Peter Vagn; Geiker, Mette Rica

    2012-01-01

    Both on-site investigations and laboratory studies have shown that different corrosion rates are obtained when different commercially available corrosion rate instruments are used. The different electrochemical techniques and the measurement parameters used, i.e. polarisation current and time......, are in some studies considered the main reasons for the variations. This paper presents an experimental study on the quantitative effect of polarisation time and current on the measured polarisation resistance – and thus the corrosion current density – of passively and actively corroding steel. Two...... electrochemical techniques often used in instruments for on-site corrosion rate measurements are investigated. On passively corroding reinforcement the measured polarisation resistance was for both techniques found to be highly affected by the polarisation time and current and no plateaus at either short or long...

  16. Measurement of Bacterial Bioluminescence Intensity and Spectrum: Current Physical Techniques and Principles.

    Science.gov (United States)

    Jia, Kun; Ionescu, Rodica Elena

    2016-01-01

    : Bioluminescence is light production by living organisms, which can be observed in numerous marine creatures and some terrestrial invertebrates. More specifically, bacterial bioluminescence is the "cold light" produced and emitted by bacterial cells, including both wild-type luminescent and genetically engineered bacteria. Because of the lively interplay of synthetic biology, microbiology, toxicology, and biophysics, different configurations of whole-cell biosensors based on bacterial bioluminescence have been designed and are widely used in different fields, such as ecotoxicology, food toxicity, and environmental pollution. This chapter first discusses the background of the bioluminescence phenomenon in terms of optical spectrum. Platforms for bacterial bioluminescence detection using various techniques are then introduced, such as a photomultiplier tube, charge-coupled device (CCD) camera, micro-electro-mechanical systems (MEMS), and complementary metal-oxide-semiconductor (CMOS) based integrated circuit. Furthermore, some typical biochemical methods to optimize the analytical performances of bacterial bioluminescent biosensors/assays are reviewed, followed by a presentation of author's recent work concerning the improved sensitivity of a bioluminescent assay for pesticides. Finally, bacterial bioluminescence as implemented in eukaryotic cells, bioluminescent imaging, and cancer cell therapies is discussed.

  17. A Streaming Potential/Current-Based Microfluidic Direct Current Generator for Self-Powered Nanosystems.

    Science.gov (United States)

    Zhang, Rui; Wang, Sihong; Yeh, Min-Hsin; Pan, Caofeng; Lin, Long; Yu, Ruomeng; Zhang, Yan; Zheng, Li; Jiao, Zongxia; Wang, Zhong Lin

    2015-11-01

    A simple but practical method to convert the hydroenergy of microfluids into continuous electrical output is reported. Based on the principle of streaming potential/current, a microfluidic generator (MFG) is demonstrated using patterned micropillar arrays as a quasi-porous flow channel. The continuous electrical output makes this MFG particularly suitable as a power source in self-powered systems. Using the proposed MFG to power a single nanowire-based pH sensor, a self-powered fluid sensor system is demonstrated.

  18. Memory Based Machine Intelligence Techniques in VLSI hardware

    OpenAIRE

    James, Alex Pappachen

    2012-01-01

    We briefly introduce the memory based approaches to emulate machine intelligence in VLSI hardware, describing the challenges and advantages. Implementation of artificial intelligence techniques in VLSI hardware is a practical and difficult problem. Deep architectures, hierarchical temporal memories and memory networks are some of the contemporary approaches in this area of research. The techniques attempt to emulate low level intelligence tasks and aim at providing scalable solutions to high ...

  19. Bond strength with custom base indirect bonding techniques.

    Science.gov (United States)

    Klocke, Arndt; Shi, Jianmin; Kahl-Nieke, Bärbel; Bismayer, Ulrich

    2003-04-01

    Different types of adhesives for indirect bonding techniques have been introduced recently. But there is limited information regarding bond strength with these new materials. In this in vitro investigation, stainless steel brackets were bonded to 100 permanent bovine incisors using the Thomas technique, the modified Thomas technique, and light-cured direct bonding for a control group. The following five groups of 20 teeth each were formed: (1) modified Thomas technique with thermally cured base composite (Therma Cure) and chemically cured sealant (Maximum Cure), (2) Thomas technique with thermally cured base composite (Therma Cure) and chemically cured sealant (Custom I Q), (3) Thomas technique with light-cured base composite (Transbond XT) and chemically cured sealant (Sondhi Rapid Set), (4) modified Thomas technique with chemically cured base adhesive (Phase II) and chemically cured sealant (Maximum Cure), and (5) control group directly bonded with light-cured adhesive (Transbond XT). Mean bond strengths in groups 3, 4, and 5 were 14.99 +/- 2.85, 15.41 +/- 3.21, and 13.88 +/- 2.33 MPa, respectively, and these groups were not significantly different from each other. Groups 1 (mean bond strength 7.28 +/- 4.88 MPa) and 2 (mean bond strength 7.07 +/- 4.11 MPa) showed significantly lower bond strengths than groups 3, 4, and 5 and a higher probability of bond failure. Both the original (group 2) and the modified (group 1) Thomas technique were able to achieve bond strengths comparable to the light-cured direct bonded control group.

  20. Memory Based Machine Intelligence Techniques in VLSI hardware

    CERN Document Server

    James, Alex Pappachen

    2012-01-01

    We briefly introduce the memory based approaches to emulate machine intelligence in VLSI hardware, describing the challenges and advantages. Implementation of artificial intelligence techniques in VLSI hardware is a practical and difficult problem. Deep architectures, hierarchical temporal memories and memory networks are some of the contemporary approaches in this area of research. The techniques attempt to emulate low level intelligence tasks and aim at providing scalable solutions to high level intelligence problems such as sparse coding and contextual processing.

  1. Cesarean delivery technique: evidence or tradition? A review of the evidence-based cesarean delivery.

    Science.gov (United States)

    Encarnacion, Betsy; Zlatnik, Marya G

    2012-08-01

    Cesarean delivery is the most common surgical procedure performed in the United States, yet the techniques used during this procedure often vary significantly among providers. The purpose of this review was to evaluate and outline current evidence behind the cesarean delivery technique. A search of the PubMed database was conducted using the terms cesarean section and cesarean delivery and the technique of interest, for example, cesarean section prophylactic antibiotics. Few aspects of the cesarean delivery were found to have high-quality consistent evidence to support use of a particular technique. Because many aspects of the procedure are based on limited or no data, more studies on specific cesarean delivery techniques are clearly needed. Providers should be aware of which components of the cesarean delivery are evidence-based versus not when performing this procedure.

  2. Image analysis techniques associated with automatic data base generation.

    Science.gov (United States)

    Bond, A. D.; Ramapriyan, H. K.; Atkinson, R. J.; Hodges, B. C.; Thomas, D. T.

    1973-01-01

    This paper considers some basic problems relating to automatic data base generation from imagery, the primary emphasis being on fast and efficient automatic extraction of relevant pictorial information. Among the techniques discussed are recursive implementations of some particular types of filters which are much faster than FFT implementations, a 'sequential similarity detection' technique of implementing matched filters, and sequential linear classification of multispectral imagery. Several applications of the above techniques are presented including enhancement of underwater, aerial and radiographic imagery, detection and reconstruction of particular types of features in images, automatic picture registration and classification of multiband aerial photographs to generate thematic land use maps.

  3. Study on UPF Harmonic Current Detection Method Based on DSP

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, H J [Northwestern Polytechnical University, Xi' an 710072 (China); Pang, Y F [Xi' an University of Technology, Xi' an 710048 (China); Qiu, Z M [Xi' an University of Technology, Xi' an 710048 (China); Chen, M [Northwestern Polytechnical University, Xi' an 710072 (China)

    2006-10-15

    Unity power factor (UPF) harmonic current detection method applied to active power filter (APF) is presented in this paper. The intention of this method is to make nonlinear loads and active power filter in parallel to be an equivalent resistance. So after compensation, source current is sinusoidal, and has the same shape of source voltage. Meanwhile, there is no harmonic in source current, and the power factor becomes one. The mathematic model of proposed method and the optimum project for equivalent low pass filter in measurement are presented. Finally, the proposed detection method applied to a shunt active power filter experimental prototype based on DSP TMS320F2812 is developed. Simulation and experiment results indicate the method is simple and easy to implement, and can obtain the real-time calculation of harmonic current exactly.

  4. A picture is worth a thousand words : content-based image retrieval techniques

    NARCIS (Netherlands)

    Thomée, Bart

    2010-01-01

    In my dissertation I investigate techniques for improving the state of the art in content-based image retrieval. To place my work into context, I highlight the current trends and challenges in my field by analyzing over 200 recent articles. Next, I propose a novel paradigm called ‘artificial imagina

  5. Current trends in pulp therapy: a survey analyzing pulpotomy techniques taught in pediatric dental residency programs.

    Science.gov (United States)

    Walker, Laquia A; Sanders, Brian J; Jones, James E; Williamson, C Andrew; Dean, Jeffrey A; Legan, Joseph J; Maupome, Gerardo

    2013-01-01

    The study's purpose was to survey directors of pediatric dental residency programs in order to evaluate the materials currently being taught and used for pulpotomy procedures for primary teeth in educational and clinical settings. A web-based survey was emailed to all graduate pediatric dental residency program directors in the United States. Seventy one emails were sent to program directors, 47 responded but only 39 respondents (55%) were included in the study. Results suggested a slight decrease in utilization of formocresol 1:5 dilution (Pformocresol (18% of respondents) were systemic health concerns and carcinogenicity, in addition to evidence-based literature. Even though 25% of respondents have begun to use MTA for primary pulpotomy procedures, the most common reason for utilization of other medicaments over MTA was its higher cost. With 82% of graduate pediatric dental residency programs still utilizing formocresol 1:5 dilution for pulpotomy procedures in primary teeth, there has been no major shift away from its clinical use, in spite of increased usage of newer medicaments over the last 5 years.

  6. Runtime Monitoring Technique to handle Tautology based SQL Injection Attacks

    Directory of Open Access Journals (Sweden)

    Ramya Dharam

    2015-05-01

    Full Text Available Software systems, like web applications, are often used to provide reliable online services such as banking, shopping, social networking, etc., to users. The increasing use of such systems has led to a high need for assuring confidentiality, integrity, and availability of user data. SQL Injection Attacks (SQLIAs is one of the major security threats to web applications. It allows attackers to get unauthorized access to the back-end database consisting of confidential user information. In this paper we present and evaluate a Runtime Monitoring Technique to detect and prevent tautology based SQLIAs in web applications. Our technique monitors the behavior of the application during its post- deployment to identify all the tautology based SQLIAs. A framework called Runtime Monitoring Framework, that implements our technique, is used in the development of runtime monitors. The framework uses two pre-deployment testing techniques, such as basis-path and data-flow to identify a minimal set of all legal/valid execution paths of the application. Runtime monitors are then developed and integrated to perform runtime monitoring of the application, during its post-deployment for the identified valid/legal execution paths. For evaluation we targeted a subject application with a large number of both legitimate inputs and illegitimate tautology based inputs, and measured the performance of the proposed technique. The results of our study show that runtime monitor developed for the application was successfully able to detect all the tautology based attacks without generating any false positives.

  7. Laser-based direct-write techniques for cell printing.

    Science.gov (United States)

    Schiele, Nathan R; Corr, David T; Huang, Yong; Raof, Nurazhani Abdul; Xie, Yubing; Chrisey, Douglas B

    2010-09-01

    Fabrication of cellular constructs with spatial control of cell location (+/-5 microm) is essential to the advancement of a wide range of applications including tissue engineering, stem cell and cancer research. Precise cell placement, especially of multiple cell types in co- or multi-cultures and in three dimensions, can enable research possibilities otherwise impossible, such as the cell-by-cell assembly of complex cellular constructs. Laser-based direct writing, a printing technique first utilized in electronics applications, has been adapted to transfer living cells and other biological materials (e.g., enzymes, proteins and bioceramics). Many different cell types have been printed using laser-based direct writing, and this technique offers significant improvements when compared to conventional cell patterning techniques. The predominance of work to date has not been in application of the technique, but rather focused on demonstrating the ability of direct writing to pattern living cells, in a spatially precise manner, while maintaining cellular viability. This paper reviews laser-based additive direct-write techniques for cell printing, and the various cell types successfully laser direct-written that have applications in tissue engineering, stem cell and cancer research are highlighted. A particular focus is paid to process dynamics modeling and process-induced cell injury during laser-based cell direct writing.

  8. Laser-based direct-write techniques for cell printing

    Energy Technology Data Exchange (ETDEWEB)

    Schiele, Nathan R; Corr, David T [Biomedical Engineering Department, Rensselaer Polytechnic Institute, Troy, NY (United States); Huang Yong [Department of Mechanical Engineering, Clemson University, Clemson, SC (United States); Raof, Nurazhani Abdul; Xie Yubing [College of Nanoscale Science and Engineering, University at Albany, SUNY, Albany, NY (United States); Chrisey, Douglas B, E-mail: schien@rpi.ed, E-mail: chrisd@rpi.ed [Material Science and Engineering Department, Rensselaer Polytechnic Institute, Troy, NY (United States)

    2010-09-15

    Fabrication of cellular constructs with spatial control of cell location ({+-}5 {mu}m) is essential to the advancement of a wide range of applications including tissue engineering, stem cell and cancer research. Precise cell placement, especially of multiple cell types in co- or multi-cultures and in three dimensions, can enable research possibilities otherwise impossible, such as the cell-by-cell assembly of complex cellular constructs. Laser-based direct writing, a printing technique first utilized in electronics applications, has been adapted to transfer living cells and other biological materials (e.g., enzymes, proteins and bioceramics). Many different cell types have been printed using laser-based direct writing, and this technique offers significant improvements when compared to conventional cell patterning techniques. The predominance of work to date has not been in application of the technique, but rather focused on demonstrating the ability of direct writing to pattern living cells, in a spatially precise manner, while maintaining cellular viability. This paper reviews laser-based additive direct-write techniques for cell printing, and the various cell types successfully laser direct-written that have applications in tissue engineering, stem cell and cancer research are highlighted. A particular focus is paid to process dynamics modeling and process-induced cell injury during laser-based cell direct writing. (topical review)

  9. PCA Based Rapid and Real Time Face Recognition Technique

    Directory of Open Access Journals (Sweden)

    T R Chandrashekar

    2013-12-01

    Full Text Available Economical and efficient that is used in various applications is face Biometric which has been a popular form biometric system. Face recognition system is being a topic of research for last few decades. Several techniques are proposed to improve the performance of face recognition system. Accuracy is tested against intensity, distance from camera, and pose variance. Multiple face recognition is another subtopic which is under research now a day. Speed at which the technique works is a parameter under consideration to evaluate a technique. As an example a support vector machine performs really well for face recognition but the computational efficiency degrades significantly with increase in number of classes. Eigen Face technique produces quality features for face recognition but the accuracy is proved to be comparatively less to many other techniques. With increase in use of core processors in personal computers and application demanding speed in processing and multiple face detection and recognition system (for example an entry detection system in shopping mall or an industry, demand for such systems are cumulative as there is a need for automated systems worldwide. In this paper we propose a novel system of face recognition developed with C# .Net that can detect multiple faces and can recognize the faces parallel by utilizing the system resources and the core processors. The system is built around Haar Cascade based face detection and PCA based face recognition system with C#.Net. Parallel library designed for .Net is used to aide to high speed detection and recognition of the real time faces. Analysis of the performance of the proposed technique with some of the conventional techniques reveals that the proposed technique is not only accurate, but also is fast in comparison to other techniques.

  10. Cleaning Verification Monitor Technique Based on Infrared Optical Methods

    Science.gov (United States)

    2004-10-01

    Cleaning Verification Techniques.” Real-time methods to provide both qualitative and quantitative assessments of surface cleanliness are needed for a...detection VCPI method offer a wide range of complementary capabilities in real-time surface cleanliness verification. Introduction Currently...also has great potential to reduce or eliminate premature failures of surface coatings caused by a lack of surface cleanliness . Additional

  11. A Knowledge—Based Specification Technique for Protocol Development

    Institute of Scientific and Technical Information of China (English)

    张尧学; 史美林; 等

    1993-01-01

    is paper proposes a knowledge-based specification technique(KST)for protocol development.This technique semi-automatically translates a protocol described in an informal description(natural languages or graphs)into one described in forml specifications(Estells and SDL).The translation processes are suported by knowledge stored in the knowledge base.This paper discusses the concept,the specification control mechanism of KST and the rules and algorithms for production of FSM's which is the basis of Estelle and SDL.

  12. Current development of saliva/oral fluid-based diagnostics.

    Science.gov (United States)

    Yeh, Chih-Ko; Christodoulides, Nicolaos J; Floriano, Pierre N; Miller, Craig S; Ebersole, Jeffrey L; Weigum, Shannon E; McDevitt, John; Redding, Spencer W

    2010-07-01

    Saliva can be easily obtained in medical and non-medical settings, and contains numerous bio-molecules, including those typically found in serum for disease detection and monitoring. In the past two decades, the achievements of high-throughput approaches afforded by biotechnology and nanotechnology allow for disease-specific salivary biomarker discovery and establishment of rapid, multiplex, and miniaturized analytical assays. These developments have dramatically advanced saliva-based diagnostics. In this review, we discuss the current consensus on development of saliva/oral fluid-based diagnostics and provide a summary of recent research advancements of the Texas-Kentucky Saliva Diagnostics Consortium. In the foreseeable future, current research on saliva based diagnostic methods could revolutionize health care.

  13. Analysis of the current rib support practices and techniques in U.S. coal mines.

    Science.gov (United States)

    Mohamed, Khaled M; Murphy, Michael M; Lawson, Heather E; Klemetti, Ted

    2016-01-01

    Design of rib support systems in U.S. coal mines is based primarily on local practices and experience. A better understanding of current rib support practices in U.S. coal mines is crucial for developing a sound engineering rib support design tool. The objective of this paper is to analyze the current practices of rib control in U.S. coal mines. Twenty underground coal mines were studied representing various coal basins, coal seams, geology, loading conditions, and rib control strategies. The key findings are: (1) any rib design guideline or tool should take into account external rib support as well as internal bolting; (2) rib bolts on their own cannot contain rib spall, especially in soft ribs subjected to significant load-external rib control devices such as mesh are required in such cases to contain rib sloughing; (3) the majority of the studied mines follow the overburden depth and entry height thresholds recommended by the Program Information Bulletin 11-29 issued by the Mine Safety and Health Administration; (4) potential rib instability occurred when certain geological features prevailed-these include draw slate and/or bone coal near the rib/roof line, claystone partings, and soft coal bench overlain by rock strata; (5) 47% of the studied rib spall was classified as blocky-this could indicate a high potential of rib hazards; and (6) rib injury rates of the studied mines for the last three years emphasize the need for more rib control management for mines operating at overburden depths between 152.4 m and 304.8 m.

  14. Current technology and techniques in re-mineralization of white spot lesions: A systematic review

    Science.gov (United States)

    Podray, Susan S.

    White Spot lesions are a common iatrogenic occurrence on patients who are treated with fixed orthodontic appliances. There is a dynamic chemical interaction between enamel and saliva at the tooth surface that allow a lesion to have phase changes involving demineralization of enamel and reminerlization. This is due to calcium and phosphate dissolved in saliva that is deposited onto the tooth surface or removed depending on the surrounding pH. Caseinphosphopeptide-amorphous calcium phosphate (CPP-ACP) is gaining popularity in dentistry as a way to increase the available level of calcium and phosphate in plaque and saliva to improve the chemical gradient so that if favors reminerlization. The aim of our investigation is to search the available current literature and formulate a recommendation for use of CPP-ACP in orthodontics. Publications from the following electronic databases were searched: PubMed, Web of Science, Cochrane Library and Science Direct. Searches from August 2010 to April 1st 2012 were performed under the terms "MI Paste OR Recaldent OR caseinphosphopeptide-amorphous calcium phosphate OR CPP-ACP or tooth mousse". The searches yielded 155 articles, These were reviewed for relevance based on inclusion and exclusion criteria. Articles with inappropriate study design or no outcome measures at both baseline and end point were also excluded. 13 articles were deemed of relevance with a high quality study design and were included in this study for evaluation. The current literature suggests a preventative treatment regimen in which MI Paste Plus is used. It should be delivered once daily prior to bed after oral hygiene for 3 minutes in a fluoride tray, throughout orthodontic treatment. It should be recommended for high risk patients determined by poor oral hygiene, as seen by the inability to remove plaque from teeth and appliances. This protocol may prevent or assist in the remineralization of enamel white spot lesions during and after orthodontic treatment.

  15. Analysis of the current rib support practices and techniques in U.S. coal mines

    Institute of Scientific and Technical Information of China (English)

    Mohamed Khaled M.; Murphy Michael M.; Lawson Heather E.; Klemetti Ted

    2016-01-01

    Design of rib support systems in U.S. coal mines is based primarily on local practices and experience. A better understanding of current rib support practices in U.S. coal mines is crucial for developing a sound engineering rib support design tool. The objective of this paper is to analyze the current practices of rib control in U.S. coal mines. Twenty underground coal mines were studied representing various coal basins, coal seams, geology, loading conditions, and rib control strategies. The key findings are:(1) any rib design guideline or tool should take into account external rib support as well as internal bolting;(2) rib bolts on their own cannot contain rib spall, especially in soft ribs subjected to significant load—external rib control devices such as mesh are required in such cases to contain rib sloughing;(3) the majority of the studied mines follow the overburden depth and entry height thresholds recommended by the Program Information Bulletin 11-29 issued by the Mine Safety and Health Administration;(4) potential rib insta-bility occurred when certain geological features prevailed—these include draw slate and/or bone coal near the rib/roof line, claystone partings, and soft coal bench overlain by rock strata;(5) 47%of the stud-ied rib spall was classified as blocky—this could indicate a high potential of rib hazards;and (6) rib injury rates of the studied mines for the last three years emphasize the need for more rib control management for mines operating at overburden depths between 152.4 m and 304.8 m.

  16. The issues of current rainfall estimation techniques in mountain natural multi-hazard investigation

    Science.gov (United States)

    Zhuo, Lu; Han, Dawei; Chen, Ningsheng; Wang, Tao

    2017-04-01

    Mountain hazards (e.g., landslides, debris flows, and floods) induced by rainfall are complex phenomena that require good knowledge of rainfall representation at different spatiotemporal scales. This study reveals rainfall estimation from gauges is rather unrepresentative over a large spatial area in mountain regions. As a result, the conventional practice of adopting the triggering threshold for hazard early warning purposes is insufficient. The main reason is because of the huge orographic influence on rainfall distribution. Modern rainfall estimation methods such as numerical weather prediction modelling and remote sensing utilising radar from the space or on land are able to provide spatially more representative rainfall information in mountain areas. But unlike rain gauges, they only indirectly provide rainfall measurements. Remote sensing suffers from many sources of errors such as weather conditions, attenuation and sampling methods, while numerical weather prediction models suffer from spatiotemporal and amplitude errors depending on the model physics, dynamics, and model configuration. A case study based on Sichuan, China is used to illustrate the significant difference among the three aforementioned rainfall estimation methods. We argue none of those methods can be relied on individually, and the challenge is on how to make the full utilisation of the three methods conjunctively because each of them only provides partial information. We propose that a data fusion approach should be adopted based on the Bayesian inference method. However such an approach requires the uncertainty information from all those estimation techniques which still need extensive research. We hope this study will raise the awareness of this important issue and highlight the knowledge gap that should be filled in so that such a challenging problem could be tackled collectively by the community.

  17. Experimental comparison of different oscillation-based test techniques in an analog block

    Science.gov (United States)

    Suenaga, Kay; Picos, Rodrigo; Bota, Sebastia; Roca, Miquel; Garcia-Moreno, Eugeni

    2005-06-01

    This paper experimentally analyses the capabilities of an Oscillation-Based Test technique for diagnosis purposes. To evaluate the feasibility of this test strategy, the technique is applied to an Operational Transconductance Amplifier with fault injection capabilities. The application of this methodology has low impact on circuit performances. Voltage and current magnitude have been considered as test observables. The effects of catastrophic and parametric defects (bridges, opens and shorts) are analyzed in this work. Results show that by a right choice of the test observable, this technique provides high fault coverage levels even in the case of process variations.

  18. Fault Based Techniques for Testing Boolean Expressions: A Survey

    CERN Document Server

    Badhera, Usha; Taruna, S

    2012-01-01

    Boolean expressions are major focus of specifications and they are very much prone to introduction of faults, this survey presents various fault based testing techniques. It identifies that the techniques differ in their fault detection capabilities and generation of test suite. The various techniques like Cause effect graph, meaningful impact strategy, Branch Operator Strategy (BOR), BOR+MI, MUMCUT, Modified Condition/ Decision Coverage (MCDC) has been considered. This survey describes the basic algorithms and fault categories used by these strategies for evaluating their performance. Finally, it contains short summaries of the papers that use Boolean expressions used to specify the requirements for detecting faults. These techniques have been empirically evaluated by various researchers on a simplified safety related real time control system.

  19. Least-squares based iterative multipath super-resolution technique

    CERN Document Server

    Nam, Wooseok

    2011-01-01

    In this paper, we study the problem of multipath channel estimation for direct sequence spread spectrum signals. To resolve multipath components arriving within a short interval, we propose a new algorithm called the least-squares based iterative multipath super-resolution (LIMS). Compared to conventional super-resolution techniques, such as the multiple signal classification (MUSIC) and the estimation of signal parameters via rotation invariance techniques (ESPRIT), our algorithm has several appealing features. In particular, even in critical situations where the conventional super-resolution techniques are not very powerful due to limited data or the correlation between path coefficients, the LIMS algorithm can produce successful results. In addition, due to its iterative nature, the LIMS algorithm is suitable for recursive multipath tracking, whereas the conventional super-resolution techniques may not be. Through numerical simulations, we show that the LIMS algorithm can resolve the first arrival path amo...

  20. Current radiological techniques used to evaluate unilateral partial ureteral obstruction: an experimental rabbit study.

    Science.gov (United States)

    Yazıcı, Mehmet; Celebi, Suleyman; Kuzdan, Özgür; Koçan, Hüseyin; Ayyıldız, Halil Suat; Bayrak, İlkay Koray; Bilgici, Meltem Ceyhan; Yapıcı, Oktay; Kefeli, Mehmet; Arıtürk, Ender

    2015-07-01

    The aim of this study was to evaluate functional and prognostic benefits of Doppler ultrasonography (DU), diuretic renal scintigraphy (DRS), and magnetic resonance urography (MRU) during diagnosis and follow-up of ureteropelvic junction obstruction (UPJO) and to examine apoptosis rates caused by UPJO in an experimental rabbit model. Twenty-four rabbits were divided randomly into two groups. The left kidneys of 15 rabbits from the first group underwent Ulm-Miller surgery to create UPJO, whereas the left kidneys of nine rabbits from the second group underwent sham surgery. A pressure flow study (Whitaker's test) was done during postoperative week 6. Based on the Whitaker test, the DU, DRS, and MRU findings were compared. The number of apoptotic renal cells was counted after death. The Whitaker test run during postoperative week 6 revealed obstructions in 15 rabbits from group 1; the nine rabbits of the sham group had no obstructions. Sensitivity and specificity of DRS were 93.3 and 88.8 %, respectively, and those of MRU were 93.3 and 88.8 %, respectively. The postoperative mean RI values were significantly higher than the preoperative values, associated with sensitivity of 86.6 % and specificity of 77.5 % for detecting UPJO. DRS, MRU, and RI could not predict UPJO in one (8 %), one (8 %), and two (16 %) kidneys, respectively. Likelihood ratio (LR) was 8.4 for MRU and scintigraphy, while for RI, LR was 3.9. Pathology specimens revealed that all kidneys with UPJO underwent apoptosis, and the number of apoptotic cells was significantly higher on the UPJO-created side than on the contralateral and in the sham group (p < 0.05). No test predicted all apoptosis related to UPJO. The RI, DRS, and DMRU results correlated with the pressure flow results for detecting UPJO. No single radiological technique predicted all initial UPJO-created kidneys that concluded with apoptosis. Further studies are required to seek with better methods for diagnosing an obstruction or to define a

  1. Modeling Current Transfer from PV Modules Based on Meteorological Data

    Energy Technology Data Exchange (ETDEWEB)

    Hacke, Peter; Smith, Ryan; Kurtz, Sarah; Jordan, Dirk; Wohlgemuth, John

    2016-11-21

    Current transferred from the active cell circuit to ground in modules undergoing potential-induced degradation (PID) stress is analyzed with respect to meteorological data. Duration and coulombs transferred as a function of whether the module is wet (from dew or rain) or the extent of uncondensed surface humidity are quantified based on meteorological indicators. With this, functions predicting the mode and rate of coulomb transfer are developed for use in estimating the relative PID stress associated with temperature, moisture, and system voltage in any climate. Current transfer in a framed crystalline silicon module is relatively high when there is no condensed water on the module, whereas current transfer in a thin-film module held by edge clips is not, and displays a greater fraction of coulombs transferred when wet compared to the framed module in the natural environment.

  2. Alternating current organic light emitting diodes based on polymer heterojunction

    Institute of Scientific and Technical Information of China (English)

    Yewen Jiang(蒋业文); Haishu Tan(谭海曙); Jianquan Yao(姚建铨)

    2003-01-01

    Most alternating current (ac) polymer EL (electroluminescent) devices to date are based on symmetricalstructure. Here novel alternating current EL devices with asymmetric structure are successfully fabricatedby using a hole type polymer PDDOPV [poly (2,5-bis (dodecyloxy)-phenylenevinylene)] and an electrontype polymer PPQ [poly (phenyl quinoxaline)]. We report that performance of polymer devices withheterojunction in ac operation is not so sensitive to thickness of the two polymer layers as in direct current(dc) operation. This new advantage of ac operation mode over dc means easy production and cheapfacilities in large-scale production in the near future. Different emission spectra are obtained when ourac devices operate in ac mode, forward and reverse bias. Emission spectrum at reverse bias includes twoparts: one is from PDDOPV, the other is from PPQ.

  3. A Neuron Model Based Ultralow Current Sensor System for Bioapplications

    Directory of Open Access Journals (Sweden)

    A. K. M. Arifuzzman

    2016-01-01

    Full Text Available An ultralow current sensor system based on the Izhikevich neuron model is presented in this paper. The Izhikevich neuron model has been used for its superior computational efficiency and greater biological plausibility over other well-known neuron spiking models. Of the many biological neuron spiking features, regular spiking, chattering, and neostriatal spiny projection spiking have been reproduced by adjusting the parameters associated with the model at hand. This paper also presents a modified interpretation of the regular spiking feature in which the firing pattern is similar to that of the regular spiking but with improved dynamic range offering. The sensor current ranges between 2 pA and 8 nA and exhibits linearity in the range of 0.9665 to 0.9989 for different spiking features. The efficacy of the sensor system in detecting low amount of current along with its high linearity attribute makes it very suitable for biomedical applications.

  4. A Novel Nanofabrication Technique of Silicon-Based Nanostructures

    Science.gov (United States)

    Meng, Lingkuan; He, Xiaobin; Gao, Jianfeng; Li, Junjie; Wei, Yayi; Yan, Jiang

    2016-11-01

    A novel nanofabrication technique which can produce highly controlled silicon-based nanostructures in wafer scale has been proposed using a simple amorphous silicon (α-Si) material as an etch mask. SiO2 nanostructures directly fabricated can serve as nanotemplates to transfer into the underlying substrates such as silicon, germanium, transistor gate, or other dielectric materials to form electrically functional nanostructures and devices. In this paper, two typical silicon-based nanostructures such as nanoline and nanofin have been successfully fabricated by this technique, demonstrating excellent etch performance. In addition, silicon nanostructures fabricated above can be further trimmed to less than 10 nm by combing with assisted post-treatment methods. The novel nanofabrication technique will be expected a new emerging technology with low process complexity and good compatibility with existing silicon integrated circuit and is an important step towards the easy fabrication of a wide variety of nanoelectronics, biosensors, and optoelectronic devices.

  5. Membrane-based microextraction techniques in analytical chemistry: A review.

    Science.gov (United States)

    Carasek, Eduardo; Merib, Josias

    2015-06-23

    The use of membrane-based sample preparation techniques in analytical chemistry has gained growing attention from the scientific community since the development of miniaturized sample preparation procedures in the 1990s. The use of membranes makes the microextraction procedures more stable, allowing the determination of analytes in complex and "dirty" samples. This review describes some characteristics of classical membrane-based microextraction techniques (membrane-protected solid-phase microextraction, hollow-fiber liquid-phase microextraction and hollow-fiber renewal liquid membrane) as well as some alternative configurations (thin film and electromembrane extraction) used successfully for the determination of different analytes in a large variety of matrices, some critical points regarding each technique are highlighted.

  6. Full-duplex MIMO system based on antenna cancellation technique

    DEFF Research Database (Denmark)

    Foroozanfard, Ehsan; Franek, Ondrej; Tatomirescu, Alexandru

    2014-01-01

    The performance of an antenna cancellation technique for a multiple-input– multiple-output (MIMO) full-duplex system that is based on null-steering beamforming and antenna polarization diversity is investigated. A practical implementation of a symmetric antenna topology comprising three dual-pola...

  7. Video multiple watermarking technique based on image interlacing using DWT.

    Science.gov (United States)

    Ibrahim, Mohamed M; Abdel Kader, Neamat S; Zorkany, M

    2014-01-01

    Digital watermarking is one of the important techniques to secure digital media files in the domains of data authentication and copyright protection. In the nonblind watermarking systems, the need of the original host file in the watermark recovery operation makes an overhead over the system resources, doubles memory capacity, and doubles communications bandwidth. In this paper, a robust video multiple watermarking technique is proposed to solve this problem. This technique is based on image interlacing. In this technique, three-level discrete wavelet transform (DWT) is used as a watermark embedding/extracting domain, Arnold transform is used as a watermark encryption/decryption method, and different types of media (gray image, color image, and video) are used as watermarks. The robustness of this technique is tested by applying different types of attacks such as: geometric, noising, format-compression, and image-processing attacks. The simulation results show the effectiveness and good performance of the proposed technique in saving system resources, memory capacity, and communications bandwidth.

  8. Face Veins Based MCMT Technique for Personal Identification

    Directory of Open Access Journals (Sweden)

    Kamta Nath Mishra

    2015-08-01

    Full Text Available Face veins based personal identification is a challenging task in the field of identity verification of a person. It is because many other techniques are not identifying the uniqueness of a person in the universe. This research paper finds the uniqueness of a person on the basis of face veins based technique. In this paper five different persons face veins images have been used with different rotation angles (left/right 900 to 2700 and 3150 . For each person, eight different images at different rotations were used and for each of these images the same minimum cost minutiae tree (MCMT is obtained. Here, Prim‟s or Kruskal‟s algorithm is used for finding the MCMT from a minutiae graph. The MCMT is traversed in pre-order to generate the unique string of vertices and edge lengths. We deviated the edge lengths of each MCMT by five pixels in positive and negative directions for robustness testing. It is observed in our experiments that the traversed string which consists of vertices and edge lengths of MCMT is unique for each person and this unique sequence is correctly identifying a person with an accuracy of above 95%. Further, we have compared the performance of our proposed technique with other standard techniques and it is observed that the proposed technique is giving the promising result.

  9. The Real-Time Image Processing Technique Based on DSP

    Institute of Scientific and Technical Information of China (English)

    QI Chang; CHEN Yue-hua; HUANG Tian-shu

    2005-01-01

    This paper proposes a novel real-time image processing technique based on digital singnal processor (DSP). At the aspect of wavelet transform(WT) algorithm, the technique uses algorithm of second generation wavelet transform-lifting scheme WT that has low calculation complexity property for the 2-D image data processing. Since the processing effect of lifting scheme WT for 1-D data is better than the effect of it for 2-D data obviously, this paper proposes a reformative processing method: Transform 2-D image data to 1-D data sequence by linearization method, then process the 1-D data sequence by algorithm of lifting scheme WT. The method changes the image convolution mode,which based on the cross filtering of rows and columns. At the aspect of hardware realization, the technique optimizes the program structure of DSP to exert the operation power with the in-chip memorizer of DSP. The experiment results show that the real-time image processing technique proposed in this paper can meet the real-time requirement of video-image transmitting in the video surveillance system of electric power. So the technique is a feasible and efficient DSP solution.

  10. Reflective all-fiber current sensor based on magnetic fluids

    Science.gov (United States)

    Li, Lin; Han, Qun; Liu, Tiegen; Chen, Yaofei; Zhang, Rongxiang

    2014-08-01

    A reflective all-fiber current sensor based on magnetic fluid (MF) is reported. The MF is used as the cladding of a piece of no-core fiber which is spliced between two sections of singlemode fiber to form a singlemode-multimode-singlemode structure. An intensity based interrogation scheme with a superluminescent diode as the light source and the dual-balanced detection method is used in the sensing system. The influence of the direction of the magnetic field on the sensitivity of the sensor is also experimentally investigated and analyzed.

  11. Improved Active Harmonic Current Elimination Based on Voltage Detection.

    Directory of Open Access Journals (Sweden)

    Tianyuan Tan

    Full Text Available With the increasing penetration of power electronic equipment in modern residential distribution systems, harmonics mitigation through the distributed generation (DG interfacing converters has received significant attention. Among recently proposed methods, the so-called active resonance damper (ARD and harmonic voltage compensator (HVC based on voltage detection can effectively reduce the harmonic distortions in selected areas of distribution systems. However, it is found out that when traditional ARD algorithm is used to eliminate harmonic current injected by non-linear loads, its performance is constrained by stability problems and can at most eliminate half of the load harmonic currents. Thus, inspired by the duality between ARD and HVC, this paper presents a novel improved resistive active power filter (R-APF algorithm based on integral-decoupling control. The design guideline for its parameters is then investigated through carefully analyzing the closed-loop poles' trajectory. Computer studies demonstrate that the proposed algorithm can effectively mitigate the load harmonic currents and its performance is much better than traditional ARD based on proportional control.

  12. Simple engineering design for complex thermoelectric generators based on reduced current approach

    DEFF Research Database (Denmark)

    Wijesooriyage, Waruna Dissanayaka; Rezaniakolaei, Alireza; Rosendahl, Lasse

    2015-01-01

    Thermoelectric generators (TEGs) are niche candidate for the field of energy management as electrical generator devices. Generally, comprehensive and accurate design techniques for TEGs (thermoelectric generators), such as reduced current approach (RCA), are complex and time consuming processes....... This study develops a simple, comprehensive and accurate TEG designing technique based on RCA. The proposed method can predict the most efficient TEG architecture with more than 97% accuracy comparing to the RCA over wide range of possible temperature and zT for present TEG applications. Moreover...

  13. Ionic Current Mapping Techniques and Applications to Aluminum-Copper Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, H. S.; Jeffcoate, C. S.; Missert, N. A.; Barbour, J. C.

    1999-10-17

    Measurements have been made of the aluminum/metal galvanic couple. A wide range of geometries were investigated varying the areas of anodic and cathodic surfaces and employing specially designed galvanic cells with crevices. In situ ionic current density mapping was used to monitor galvanic corrosion and currents flowing between separated metals was measured.

  14. Proposing a Wiki-Based Technique for Collaborative Essay Writing

    Directory of Open Access Journals (Sweden)

    Mabel Ortiz Navarrete

    2014-10-01

    Full Text Available This paper aims at proposing a technique for students learning English as a foreign language when they collaboratively write an argumentative essay in a wiki environment. A wiki environment and collaborative work play an important role within the academic writing task. Nevertheless, an appropriate and systematic work assignment is required in order to make use of both. In this paper the proposed technique when writing a collaborative essay mainly attempts to provide the most effective way to enhance equal participation among group members by taking as a base computer mediated collaboration. Within this context, the students’ role is clearly defined and individual and collaborative tasks are explained.

  15. Line Search-Based Inverse Lithography Technique for Mask Design

    Directory of Open Access Journals (Sweden)

    Xin Zhao

    2012-01-01

    Full Text Available As feature size is much smaller than the wavelength of illumination source of lithography equipments, resolution enhancement technology (RET has been increasingly relied upon to minimize image distortions. In advanced process nodes, pixelated mask becomes essential for RET to achieve an acceptable resolution. In this paper, we investigate the problem of pixelated binary mask design in a partially coherent imaging system. Similar to previous approaches, the mask design problem is formulated as a nonlinear program and is solved by gradient-based search. Our contributions are four novel techniques to achieve significantly better image quality. First, to transform the original bound-constrained formulation to an unconstrained optimization problem, we propose a new noncyclic transformation of mask variables to replace the wellknown cyclic one. As our transformation is monotonic, it enables a better control in flipping pixels. Second, based on this new transformation, we propose a highly efficient line search-based heuristic technique to solve the resulting unconstrained optimization. Third, to simplify the optimization, instead of using discretization regularization penalty technique, we directly round the optimized gray mask into binary mask for pattern error evaluation. Forth, we introduce a jump technique in order to jump out of local minimum and continue the search.

  16. Vacuum Dielectric Recovery Characteristics of a Novel Current Limiting Circuit Breaker Base on Artificial Current Zero

    Institute of Scientific and Technical Information of China (English)

    JIANG Zhuangxian; ZHUANG Jinwu; WANG Chen; WU Jin; LIU Luhui

    2012-01-01

    A novel current limiting circuit breaker employs zero current switching method in cutting off DC current, which gives out a reverse impulsive current towards a high speed vacuum interrupter and force the current down to zero. This kind of breaker is simply in structure and can act in a very short time with high current limiting capability, and therefore it has a long electric life and is extremely suitable to be installed in a DC electrical system as a fault orotection utility.

  17. A comparison of two-dimensional techniques for converting magnetocardiogram maps into effective current source distributions.

    Science.gov (United States)

    Ogata, K; Kandori, A; Miyashita, T; Sekihara, K; Tsukada, K

    2011-01-01

    The aim of this study was to develop a method for converting the pseudo two-dimensional current given by a current-arrow map (CAM) into the physical current. The physical current distribution is obtained by the optimal solution in a least mean square sense with Tikhonov regularization (LMSTR). In the current dipole simulation, the current pattern differences (ΔJ) between the results of the CAM and the LMSTR with several regularization parameters (α = 10(-1)-10(-15)) are calculated. In magnetocardiographic (MCG) analysis, the depth (z(d)) of a reconstruction plane is chosen by using the coordinates of the sinus node, which is estimated from MCG signals at the early p-wave. The ΔJs at p-wave peaks, QRS-complex peaks, and T-wave peaks of MCG signals for healthy subjects are calculated. Furthermore, correlation coefficients and regression lines are also calculated from the current values of the CAM and the LMSTR during p-waves, QRS-complex, and T-waves of MCG signals. In the simulation, the ΔJs (α ≈ 10(-10)) had a minimal value. The ΔJs (α = 10(-10)) at p-wave peaks, QRS-complex peaks, and T-wave peaks of MCG signals for healthy subjects also had minimal value. The correlation coefficients of the current values given by the CAM and the LMSTR (α = 10(-10)) were greater than 0.9. Furthermore, slopes (y) of the regression lines are correlated with the depth (z(d)) (r = -0.93). Consequently, the CAM value can be transformed into the LMSTR current value by multiplying it by the slope (y) obtained from the depth (z(d)). In conclusion, the result given by the CAM can be converted into an effective physical current distribution by using the depth (z(d)).

  18. A Survey on Statistical Based Single Channel Speech Enhancement Techniques

    Directory of Open Access Journals (Sweden)

    Sunnydayal. V

    2014-11-01

    Full Text Available Speech enhancement is a long standing problem with various applications like hearing aids, automatic recognition and coding of speech signals. Single channel speech enhancement technique is used for enhancement of the speech degraded by additive background noises. The background noise can have an adverse impact on our ability to converse without hindrance or smoothly in very noisy environments, such as busy streets, in a car or cockpit of an airplane. Such type of noises can affect quality and intelligibility of speech. This is a survey paper and its object is to provide an overview of speech enhancement algorithms so that enhance the noisy speech signal which is corrupted by additive noise. The algorithms are mainly based on statistical based approaches. Different estimators are compared. Challenges and Opportunities of speech enhancement are also discussed. This paper helps in choosing the best statistical based technique for speech enhancement

  19. A Review On Segmentation Based Image Compression Techniques

    Directory of Open Access Journals (Sweden)

    S.Thayammal

    2013-11-01

    Full Text Available Abstract -The storage and transmission of imagery become more challenging task in the current scenario of multimedia applications. Hence, an efficient compression scheme is highly essential for imagery, which reduces the requirement of storage medium and transmission bandwidth. Not only improvement in performance and also the compression techniques must converge quickly in order to apply them for real time applications. There are various algorithms have been done in image compression, but everyone has its own pros and cons. Here, an extensive analysis between existing methods is performed. Also, the use of existing works is highlighted, for developing the novel techniques which face the challenging task of image storage and transmission in multimedia applications.

  20. Multivariate discrimination technique based on the Bayesian theory

    Institute of Scientific and Technical Information of China (English)

    JIN Ping; PAN Chang-zhou; XIAO Wei-guo

    2007-01-01

    A multivariate discrimination technique was established based on the Bayesian theory. Using this technique, P/S ratios of different types (e.g., Pn/Sn, Pn/Lg, Pg/Sn or Pg/Lg) measured within different frequency bands and from different stations were combined together to discriminate seismic events in Central Asia. Major advantages of the Bayesian approach are that the probability to be an explosion for any unknown event can be directly calculated given the measurements of a group of discriminants, and at the same time correlations among these discriminants can be fully taken into account. It was proved theoretically that the Bayesian technique would be optimal and its discriminating performance would be better than that of any individual discriminant as well as better than that yielded by the linear combination approach ignoring correlations among discriminants. This conclusion was also validated in this paper by applying the Bayesian approach to the above-mentioned observed data.

  1. RANKINGTHEREFACTORING TECHNIQUES BASED ON THE INTERNAL QUALITY ATTRIBUTES

    Directory of Open Access Journals (Sweden)

    Sultan Alshehri

    2014-01-01

    Full Text Available The analytic hierarchy process (AHP has been applied in many fields and especially to complex engineering problems and applications. The AHP is capable of structuring decision problems and finding mathematically determined judgments built on knowledge and experience. This suggests that AHP should prove useful in agile software development where complex decisions occur routinely. In this paper, the AHP is used to rank the refactoring techniques based on the internal code quality attributes. XP encourages applying the refactoring where the code smells bad. However, refactoring may consume more time and efforts.So, to maximize the benefits of the refactoring in less time and effort, AHP has been applied to achieve this purpose. It was found that ranking the refactoring techniques helped the XP team to focus on the technique that improve the code and the XP development process in general.

  2. Predicting core losses and efficiency of SRM in continuous current mode of operation using improved analytical technique

    Energy Technology Data Exchange (ETDEWEB)

    Parsapour, Amir, E-mail: amirparsapour@gmail.com [Department of Electrical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Dehkordi, Behzad Mirzaeian, E-mail: mirzaeian@eng.ui.ac.ir [Department of Electrical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Moallem, Mehdi, E-mail: moallem@cc.iut.ac.ir [Department of Electrical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

    2015-03-15

    In applications in which the high torque per ampere at low speed and rated power at high speed are required, the continuous current method is the best solution. However, there is no report on calculating the core loss of SRM in continuous current mode of operation. Efficiency and iron loss calculation which are complex tasks in case of conventional mode of operation is even more involved in continuous current mode of operation. In this paper, the Switched Reluctance Motor (SRM) is modeled using finite element method and core loss and copper loss of SRM in discontinuous and continuous current modes of operation are calculated using improved analytical techniques to include the minor loop losses in continuous current mode of operation. Motor efficiency versus speed in both operation modes is obtained and compared. - Highlights: • Continuous current method for Switched Reluctance Motor (SRM) is explained. • An improved analytical technique is presented for SRM core loss calculation. • SRM losses in discontinuous and continuous current operation modes are presented. • Effect of mutual inductances on SRM performance is investigated.

  3. Current and Ongoing Internet Crime Tendencies and Techniques. Preventive Legislation Measures in Romania

    Directory of Open Access Journals (Sweden)

    Florin Postolache

    2010-06-01

    Full Text Available Internet crime techniques that pilfer from victims millions each year continue to plague the Internet through a range of methods. Trends and techniques identified by many organizations along with itsdescription are followed by preventative measures that will support you in being informed prior to entering into dealings and transactions over the Internet. Techniques as Auction Fraud, Counterfeit Cashier's Check, Credit Card Fraud, Debt Elimination, Parcel Courier Email Scheme, Employment/Business Opportunities,Escrow Services Fraud, Identity Theft, Internet Extortion, Investment Fraud, Lotteries, Nigerian Letter or "419", Phishing/Spoofing, Ponzi/Pyramid, Reshipping, Spam, Third Party Receiver of Funds are clarified in this paper and, also the internet crime prevention and legislative measures are treated, too.

  4. Laparoscopic Nephroureterectomy and Management of the Distal Ureter: A Review of Current Techniques and Outcomes

    Science.gov (United States)

    Viprakasit, Davis P.; Macejko, Amanda M.; Nadler, Robert B.

    2009-01-01

    Laparoscopic nephroureterectomy (LNU) is becoming an increasingly common alternative treatment for transitional cell carcinoma (TCC) of the renal pelvis and ureter due to decreased perioperative morbidity, shorter hospitalization, and comparable oncologic control with open nephroureterectomy (ONU). Mobilization of the kidney and proximal ureter may be performed through a transperitoneal, retroperitoneal, or hand-assisted approach. Each technique is associated with its own benefits and limitations, and the optimal approach is often dictated by surgeon preference. Our analysis of the literature reflects equivalent cancer control between LPN and OPN at intermediate follow-up with significantly improved perioperative morbidity following LPN. Several methods for bladder cuff excision have been advocated, however, no individual technique for management of the distal ureter proved superior. Overall, complete en-bloc resection with minimal disruption of the urinary tract should be optimized to maintain oncologic outcomes. Longer follow-up and prospective studies are needed to fully evaluate these techniques. PMID:19148293

  5. MEMS-Based Power Generation Techniques for Implantable Biosensing Applications

    Directory of Open Access Journals (Sweden)

    Jonathan Lueke

    2011-01-01

    Full Text Available Implantable biosensing is attractive for both medical monitoring and diagnostic applications. It is possible to monitor phenomena such as physical loads on joints or implants, vital signs, or osseointegration in vivo and in real time. Microelectromechanical (MEMS-based generation techniques can allow for the autonomous operation of implantable biosensors by generating electrical power to replace or supplement existing battery-based power systems. By supplementing existing battery-based power systems for implantable biosensors, the operational lifetime of the sensor is increased. In addition, the potential for a greater amount of available power allows additional components to be added to the biosensing module, such as computational and wireless and components, improving functionality and performance of the biosensor. Photovoltaic, thermovoltaic, micro fuel cell, electrostatic, electromagnetic, and piezoelectric based generation schemes are evaluated in this paper for applicability for implantable biosensing. MEMS-based generation techniques that harvest ambient energy, such as vibration, are much better suited for implantable biosensing applications than fuel-based approaches, producing up to milliwatts of electrical power. High power density MEMS-based approaches, such as piezoelectric and electromagnetic schemes, allow for supplemental and replacement power schemes for biosensing applications to improve device capabilities and performance. In addition, this may allow for the biosensor to be further miniaturized, reducing the need for relatively large batteries with respect to device size. This would cause the implanted biosensor to be less invasive, increasing the quality of care received by the patient.

  6. Is the trocar technique for tube thoracostomy safe in the current era?

    Science.gov (United States)

    John, Mohan; Razi, Syed; Sainathan, Sandeep; Stavropoulos, Christos

    2014-07-01

    A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was, 'in adult patients who require a tube thoracostomy, is the trocar technique comparable to blunt dissection in terms of rate of tube malposition or complications?' Altogether more than 258 papers were found using the reported search, of which 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. The articles included two retrospective reviews, three prospective observational studies and two prospective randomized studies. Of these, four papers concluded that the trocar technique was associated with a significantly higher rate of tube malposition and complications. One retrospective review found that the rate of tube malposition was similar in both groups; however, the trocar technique was abandoned due to the occurrence of severe complications like lung and stomach injury. Another study found that blunt dissection into the pleural space followed by the use of a trocar to direct the chest tube was as safe as and even more effective than blunt dissection alone. A randomized prospective study in cadavers comparing blunt vs sharp tip trocars reported that the use of blunt tip trocars resulted in less complications. We conclude that the trocar technique for chest tube placement should be avoided in adult patients as it is associated with a higher incidence of malposition and complications. The blunt dissection technique with digital exploration of the pleural cavity prior to chest tube placement is the safest technique and should be considered standard practice. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  7. An Efficient Image Compression Technique Based on Arithmetic Coding

    Directory of Open Access Journals (Sweden)

    Prof. Rajendra Kumar Patel

    2012-12-01

    Full Text Available The rapid growth of digital imaging applications, including desktop publishing, multimedia, teleconferencing, and high visual definition has increased the need for effective and standardized image compression techniques. Digital Images play a very important role for describing the detailed information. The key obstacle for many applications is the vast amount of data required to represent a digital image directly. The various processes of digitizing the images to obtain it in the best quality for the more clear and accurate information leads to the requirement of more storage space and better storage and accessing mechanism in the form of hardware or software. In this paper we concentrate mainly on the above flaw so that we reduce the space with best quality image compression. State-ofthe-art techniques can compress typical images from 1/10 to 1/50 their uncompressed size without visibly affecting image quality. From our study I observe that there is a need of good image compression technique which provides better reduction technique in terms of storage and quality. Arithmetic coding is the best way to reducing encoding data. So in this paper we propose arithmetic coding with walsh transformation based image compression technique which is an efficient way of reduction

  8. Current protein-based anti-angiogenic therapeutics.

    Science.gov (United States)

    Chakrabarti, Sanjukta; Barrow, Colin J; Kanwar, Rupinder K; Ramana, Venkata; Kanwar, Jagat R

    2014-01-01

    Angiogenesis is a multistep process for the formation of new blood vessels. Interactions between several cellular factors including growth factors, cytokines and hematopoietic factors lead to activation of various cellular pathways finally resulting in the extracellular matrix (ECM) degradation, endothelial cell proliferation, survival and migration. Normally, angiogenesis is an essential requirement for vascular development in growing embryos as well as in adult tissues where this process depends on the intricate balance between the activities of the pro- and anti-angiogenic factors. Abnormal angiogenesis results in aberrant vasculature leading to various pathological conditions. The most important factor implicated in angiogenic processes is vascular endothelial growth factor (VEGF) and its family of ligands and receptors. Several anti-angiogenic drugs have been developed and many more are currently in different phases of clinical trials, which target various angiogenesis-inducing agents including VEGF, VEGF receptors, angiopoietins and ECM components such as integrins. Anti-angiogenic therapy can be divided into gene-based therapy and protein-based therapy. Gene-based therapies include the use of antisense oligonucleotides, siRNA, aptamers, catalytic oligonucleotides including ribozymes and DNAzymes and transcription decoys. Protein-based therapeutics includes monoclonal antibodies, peptidomimetics, fusion proteins and decoy receptors. The later class of therapeutics has several advantages over gene-based and small molecule drugs, including specificity and complexity in functions, better tolerability, less interference with normal biological processes and lesser adverse effects due to decreased immune response by virtue of being mostly body's natural proteins. This review provides a comprehensive overview of angiogenesis and on the current protein-based anti-angiogenic therapeutics under research and in the clinic.

  9. Numeral eddy current sensor modelling based on genetic neural network

    Institute of Scientific and Technical Information of China (English)

    Yu A-Long

    2008-01-01

    This paper presents a method used to the numeral eddy current sensor modelling based on the genetic neural network to settle its nonlinear problem. The principle and algorithms of genetic neural network are introduced. In this method, the nonlinear model parameters of the numeral eddy current sensor are optimized by genetic neural network (GNN) according to measurement data. So the method remains both the global searching ability of genetic algorithm and the good local searching ability of neural network. The nonlinear model has the advantages of strong robustness,on-line modelling and high precision.The maximum nonlinearity error can be reduced to 0.037% by using GNN.However, the maximum nonlinearity error is 0.075% using the least square method.

  10. SMS Spam Filtering Technique Based on Artificial Immune System

    Directory of Open Access Journals (Sweden)

    Tarek M Mahmoud

    2012-03-01

    Full Text Available The Short Message Service (SMS have an important economic impact for end users and service providers. Spam is a serious universal problem that causes problems for almost all users. Several studies have been presented, including implementations of spam filters that prevent spam from reaching their destination. Nave Bayesian algorithm is one of the most effective approaches used in filtering techniques. The computational power of smart phones are increasing, making increasingly possible to perform spam filtering at these devices as a mobile agent application, leading to better personalization and effectiveness. The challenge of filtering SMS spam is that the short messages often consist of few words composed of abbreviations and idioms. In this paper, we propose an anti-spam technique based on Artificial Immune System (AIS for filtering SMS spam messages. The proposed technique utilizes a set of some features that can be used as inputs to spam detection model. The idea is to classify message using trained dataset that contains Phone Numbers, Spam Words, and Detectors. Our proposed technique utilizes a double collection of bulk SMS messages Spam and Ham in the training process. We state a set of stages that help us to build dataset such as tokenizer, stop word filter, and training process. Experimental results presented in this paper are based on iPhone Operating System (iOS. The results applied to the testing messages show that the proposed system can classify the SMS spam and ham with accurate compared with Nave Bayesian algorithm.

  11. Characterization techniques for graphene-based materials in catalysis

    Directory of Open Access Journals (Sweden)

    Maocong Hu

    2017-06-01

    Full Text Available Graphene-based materials have been studied in a wide range of applications including catalysis due to the outstanding electronic, thermal, and mechanical properties. The unprecedented features of graphene-based catalysts, which are believed to be responsible for their superior performance, have been characterized by many techniques. In this article, we comprehensively summarized the characterization methods covering bulk and surface structure analysis, chemisorption ability determination, and reaction mechanism investigation. We reviewed the advantages/disadvantages of different techniques including Raman spectroscopy, X-ray photoelectron spectroscopy (XPS, Fourier transform infrared spectroscopy (FTIR and Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS, X-Ray diffraction (XRD, X-ray absorption near edge structure (XANES and X-ray absorption fine structure (XAFS, atomic force microscopy (AFM, scanning electron microscopy (SEM, transmission electron microscopy (TEM, high-resolution transmission electron microscopy (HRTEM, ultraviolet-visible spectroscopy (UV-vis, X-ray fluorescence (XRF, inductively coupled plasma mass spectrometry (ICP, thermogravimetric analysis (TGA, Brunauer–Emmett–Teller (BET, and scanning tunneling microscopy (STM. The application of temperature-programmed reduction (TPR, CO chemisorption, and NH3/CO2-temperature-programmed desorption (TPD was also briefly introduced. Finally, we discussed the challenges and provided possible suggestions on choosing characterization techniques. This review provides key information to catalysis community to adopt suitable characterization techniques for their research.

  12. Bipolar square-wave current source for transient electromagnetic systems based on constant shutdown time

    Science.gov (United States)

    Wang, Shilong; Yin, Changchun; Lin, Jun; Yang, Yu; Hu, Xueyan

    2016-03-01

    Cooperative work of multiple magnetic transmitting sources is a new trend in the development of transient electromagnetic system. The key is the bipolar current waves shutdown, concurrently in the inductive load. In the past, it was difficult to use the constant clamping voltage technique to realize the synchronized shutdown of currents with different peak values. Based on clamping voltage technique, we introduce a new controlling method with constant shutdown time. We use the rising time to control shutdown time and use low voltage power source to control peak current. From the viewpoint of the circuit energy loss, by taking the high-voltage capacitor bypass resistance and the capacitor of the passive snubber circuit into account, we establish the relationship between the rising time and the shutdown time. Since the switch is not ideal, we propose a new method to test the shutdown time by the low voltage, the high voltage and the peak current. Experimental results show that adjustment of the current rising time can precisely control the value of the clamp voltage. When the rising time is fixed, the shutdown time is unchanged. The error for shutdown time deduced from the energy consumption is less than 6%. The new controlling method on current shutdown proposed in this paper can be used in the cooperative work of borehole and ground transmitting system.

  13. Bipolar square-wave current source for transient electromagnetic systems based on constant shutdown time.

    Science.gov (United States)

    Wang, Shilong; Yin, Changchun; Lin, Jun; Yang, Yu; Hu, Xueyan

    2016-03-01

    Cooperative work of multiple magnetic transmitting sources is a new trend in the development of transient electromagnetic system. The key is the bipolar current waves shutdown, concurrently in the inductive load. In the past, it was difficult to use the constant clamping voltage technique to realize the synchronized shutdown of currents with different peak values. Based on clamping voltage technique, we introduce a new controlling method with constant shutdown time. We use the rising time to control shutdown time and use low voltage power source to control peak current. From the viewpoint of the circuit energy loss, by taking the high-voltage capacitor bypass resistance and the capacitor of the passive snubber circuit into account, we establish the relationship between the rising time and the shutdown time. Since the switch is not ideal, we propose a new method to test the shutdown time by the low voltage, the high voltage and the peak current. Experimental results show that adjustment of the current rising time can precisely control the value of the clamp voltage. When the rising time is fixed, the shutdown time is unchanged. The error for shutdown time deduced from the energy consumption is less than 6%. The new controlling method on current shutdown proposed in this paper can be used in the cooperative work of borehole and ground transmitting system.

  14. Influence of DC arc current on the formation of cobalt-based nanostructures

    Indian Academy of Sciences (India)

    P B ORPE; C BALASUBRAMANIAN; S MUKHERJEE

    2017-08-01

    The synthesis of cobalt-based magnetic nanostructures using DC arc discharge technique with varying arc current is reported here. The structural, morphological, compositional and magnetic properties of thesenanostructures were studied as a function of applied arc current. Various techniques like X-ray diffraction, transmission electron microscopy, EDAX and vibrating sample magnetometry were used to carry out this studyand the results are reported here. The results clearly indicate that for a given oxygen partial pressure, an arc current of 100A favours the formation of unreacted cobalt atomic species. Also change in arc current leads to variationin phase, diversity in morphology etc. Other property changes such as thermal changes, mechanical changes etc. are not addressed here. The magnetic characterization further indicates that the anisotropy in shape plays a crucial role in deciding the magnetic properties of the nanostructured materials.We have quantified an interesting result in our experiment, that is, for a given partial pressure, 100A arc current results in unique variation in structural and magnetic properties as compared to other arc currents.

  15. Earthquake Analysis of Structure by Base Isolation Technique in SAP

    Directory of Open Access Journals (Sweden)

    T. Subramani

    2014-06-01

    Full Text Available This paper presents an overview of the present state of base isolation techniques with special emphasis and a brief on other techniques developed world over for mitigating earthquake forces on the structures. The dynamic analysis procedure for isolated structures is briefly explained. The provisions of FEMA 450 for base isolated structures are highlighted. The effects of base isolation on structures located on soft soils and near active faults are given in brief. Simple case study on natural base isolation using naturally available soils is presented. Also, the future areas of research are indicated. Earthquakes are one of nature IS greatest hazards; throughout historic time they have caused significant loss offline and severe damage to property, especially to man-made structures. On the other hand, earthquakes provide architects and engineers with a number of important design criteria foreign to the normal design process. From well established procedures reviewed by many researchers, seismic isolation may be used to provide an effective solution for a wide range of seismic design problems. The application of the base isolation techniques to protect structures against damage from earthquake attacks has been considered as one of the most effective approaches and has gained increasing acceptance during the last two decades. This is because base isolation limits the effects of the earthquake attack, a flexible base largely decoupling the structure from the ground motion, and the structural response accelerations are usually less than the ground acceleration. In general, the increase of additional viscous damping in the structure may reduce displacement and acceleration responses of the structure. This study also seeks to evaluate the effects of additional damping on the seismic response when compared with structures without additional damping for the different ground motions.

  16. GATE REPLACEMENT TECHNIQUE FOR REDUCING LEAKAGE CURRENT IN WALLACE TREE MULTIPLIER

    Directory of Open Access Journals (Sweden)

    Naveen Raman

    2013-01-01

    Full Text Available Leakage power has become more significant in the power dissipation of today’s CMOS circuits. This affects the portable battery operated devices directly. The multipliers are the main key for designing an energy efficient processor, where the multiplier design decides the digital signal processors efficiency. In this study gate replacement technique is used to reduce the leakage power in 4×4 Wallace tree multiplier architecture which has been designed by using one bit full adders. This technique replaces the gate which is at worst leakage state by a library gate .In this technique the actual output logic state is maintained in active mode. The main objective of our study is to calculate leakage power in 4×4 Wallace tree multiplier by applied gate replacement technique and it is compared with 4×4 Wallace tree full adder multiplier. The proposed method reduces 43% of leakage power in 4×4 Wallace tree multiplier.

  17. Current status of adult-to-adult living donor liver transplantation: surgical techniques and innovations

    Institute of Scientific and Technical Information of China (English)

    YAN Lü-nan; WU Hong; CHEN Zhe-yu; LIN Yi-xin

    2009-01-01

    @@ In response to critical organ shortage, transplant surgeons have utilized living donors in an attempt to decrease the mortality rate associated with waiting on the liver transplant list. Although the surgical techniques were first utilized clinically 15 years ago, the application of living donor liver transplantation (LDLT) has been somewhat limited by the steep learning curve associated with developing a program.

  18. Current Evidence on the Socket-Shield Technique: A Systematic Review.

    Science.gov (United States)

    Gharpure, Amit Srikant; Bhatavadekar, Neel B

    2016-11-29

    The recently popularised socket shield technique involves intentional retention of a thin buccal section of the remnant root at the time of immediate implant placement to preserve the buccal crestal bone from resorption. The objective of this systematic review was to assess the literature available on the socket-shield technique and weigh its biological plausibility and long-term clinical prognosis. A Systematic Search was performed in PubMed-Medline, Embase, Web of Knowledge, Google Scholar and Cochrane Central for clinical/ animal studies up to May 2016 without restrictions of language, duration, and follow-up. The literature search revealed that 15 out of 16 articles available were case reports and series, with 12 out of 16 having less than 12 months duration. Animal histological evidence demonstrated the formation of PDL and/or cementum on the implant surfaces in contact with/ in proximity to the socket-shield. Some clinical reports indicated stable results at 12 months; however, a few studies also reported infection and resorption of the socket-shield and bone loss. It would be difficult to predict the long -term success of this technique until high-quality evidence becomes available. Given some negative results, clinicians are recommended to use this technique with caution.

  19. Finding Within Cluster Dense Regions Using Distance Based Technique

    Directory of Open Access Journals (Sweden)

    Wesam Ashour

    2012-03-01

    Full Text Available One of the main categories in Data Clustering is density based clustering. Density based clustering techniques like DBSCAN are attractive because they can find arbitrary shaped clusters along with noisy outlier. The main weakness of the traditional density based algorithms like DBSCAN is clustering the different density level data sets. DBSCAN calculations done according to given parameters applied to all points in a data set, while densities of the data set clusters may be totally different. The proposed algorithm overcomes this weakness of the traditional density based algorithms. The algorithm starts with partitioning the data within a cluster to units based on a user parameter and compute the density for each unit separately. Consequently, the algorithm compares the results and merges neighboring units with closer approximate density values to become a new cluster. The experimental results of the simulation show that the proposed algorithm gives good results in finding clusters for different density cluster data set.

  20. Gabor-based fusion technique for Optical Coherence Microscopy.

    Science.gov (United States)

    Rolland, Jannick P; Meemon, Panomsak; Murali, Supraja; Thompson, Kevin P; Lee, Kye-sung

    2010-02-15

    We recently reported on an Optical Coherence Microscopy technique, whose innovation intrinsically builds on a recently reported - 2 microm invariant lateral resolution by design throughout a 2 mm cubic full-field of view - liquid-lens-based dynamic focusing optical probe [Murali et al., Optics Letters 34, 145-147, 2009]. We shall report in this paper on the image acquisition enabled by this optical probe when combined with an automatic data fusion method developed and described here to produce an in-focus high resolution image throughout the imaging depth of the sample. An African frog tadpole (Xenopus laevis) was imaged with the novel probe and the Gabor-based fusion technique, demonstrating subcellular resolution in a 0.5 mm (lateral) x 0.5 mm (axial) without the need, for the first time, for x-y translation stages, depth scanning, high-cost adaptive optics, or manual intervention. In vivo images of human skin are also presented.

  1. Clustering economies based on multiple criteria decision making techniques

    OpenAIRE

    2011-01-01

    One of the primary concerns on many countries is to determine different important factors affecting economic growth. In this paper, we study some factors such as unemployment rate, inflation ratio, population growth, average annual income, etc to cluster different countries. The proposed model of this paper uses analytical hierarchy process (AHP) to prioritize the criteria and then uses a K-mean technique to cluster 59 countries based on the ranked criteria into four groups. The first group i...

  2. Ultrabroadband Phased-Array Receivers Based on Optical Techniques

    Science.gov (United States)

    2016-02-26

    AFRL-AFOSR-VA-TR-2016-0121 Ultrabroadband Phased-array Receivers Based on Optical Techniques Christopher Schuetz UNIVERSITY OF DELAWARE Final Report...NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of Delaware 210 Hullihen Hall Newark, DE 19716 8. PERFORMING ORGANIZATION...Rev. 8/98) Prescribed by ANSI Std . Z39.18 Adobe Professional 7.0 Reset INSTRUCTIONS FOR COMPLETING SF 298 1. REPORT DATE. Full publication date

  3. Comparative analysis of affinity-based 5-hydroxymethylation enrichment techniques

    Science.gov (United States)

    Thomson, John P.; Hunter, Jennifer M.; Nestor, Colm E.; Dunican, Donncha S.; Terranova, Rémi; Moggs, Jonathan G.; Meehan, Richard R.

    2013-01-01

    The epigenetic modification of 5-hydroxymethylcytosine (5hmC) is receiving great attention due to its potential role in DNA methylation reprogramming and as a cell state identifier. Given this interest, it is important to identify reliable and cost-effective methods for the enrichment of 5hmC marked DNA for downstream analysis. We tested three commonly used affinity-based enrichment techniques; (i) antibody, (ii) chemical capture and (iii) protein affinity enrichment and assessed their ability to accurately and reproducibly report 5hmC profiles in mouse tissues containing high (brain) and lower (liver) levels of 5hmC. The protein-affinity technique is a poor reporter of 5hmC profiles, delivering 5hmC patterns that are incompatible with other methods. Both antibody and chemical capture-based techniques generate highly similar genome-wide patterns for 5hmC, which are independently validated by standard quantitative PCR (qPCR) and glucosyl-sensitive restriction enzyme digestion (gRES-qPCR). Both antibody and chemical capture generated profiles reproducibly link to unique chromatin modification profiles associated with 5hmC. However, there appears to be a slight bias of the antibody to bind to regions of DNA rich in simple repeats. Ultimately, the increased specificity observed with chemical capture-based approaches makes this an attractive method for the analysis of locus-specific or genome-wide patterns of 5hmC. PMID:24214958

  4. Controller Design of DFIG Based Wind Turbine by Using Evolutionary Soft Computational Techniques

    Directory of Open Access Journals (Sweden)

    O. P. Bharti

    2017-06-01

    Full Text Available This manuscript illustrates the controller design for a doubly fed induction generator based variable speed wind turbine by using a bioinspired scheme. This methodology is based on exploiting two proficient swarm intelligence based evolutionary soft computational procedures. The particle swarm optimization (PSO and bacterial foraging optimization (BFO techniques are employed to design the controller intended for small damping plant of the DFIG. Wind energy overview and DFIG operating principle along with the equivalent circuit model is adequately discussed in this paper. The controller design for DFIG based WECS using PSO and BFO are described comparatively in detail. The responses of the DFIG system regarding terminal voltage, current, active-reactive power, and DC-Link voltage have slightly improved with the evolutionary soft computational procedure. Lastly, the obtained output is equated with a standard technique for performance improvement of DFIG based wind energy conversion system.

  5. A Novel (DDCC-SFG-Based Systematic Design Technique of Active Filters

    Directory of Open Access Journals (Sweden)

    M. Fakhfakh

    2013-09-01

    Full Text Available This paper proposes a novel idea for the synthesis of active filters that is based on the use of signal-flow graph (SFG stamps of differential difference current conveyors (DDCCs. On the basis of an RLC passive network or a filter symbolic transfer function, an equivalent SFG is constructed. DDCCs’ SFGs are identified inside the constructed ‘active’ graph, and thus the equivalent circuit can be easily synthesized. We show that the DDCC and its ‘derivatives’, i.e. differential voltage current conveyors and the conventional current conveyors, are the main basic building blocks in such design. The practicability of the proposed technique is showcased via three application examples. Spice simulations are given to show the viability of the proposed technique.

  6. Comparing Four Touch-Based Interaction Techniques for an Image-Based Audience Response System

    NARCIS (Netherlands)

    Jorritsma, Wiard; Prins, Jonatan T.; van Ooijen, Peter M. A.

    2015-01-01

    This study aimed to determine the most appropriate touch-based interaction technique for I2Vote, an image-based audience response system for radiology education in which users need to accurately mark a target on a medical image. Four plausible techniques were identified: land-on, take-off, zoom-poin

  7. User Identification Detector Based on Power of R Technique

    Institute of Scientific and Technical Information of China (English)

    WANG Chun-jiang; YU Quan; LIU Yuan-an

    2005-01-01

    To avoid the inaccurate estimation of the active user's number and the corresponding performance degradation, a novel POR-based User Identification Detector (UID) is proposed for the Code Division Multiple Access (CDMA) systems. The new detector adopts the Power of R (POR) technique and the Multiple Signal Classification (MUSIC) method, which does not require the estimation of active users' number, and obtains lower false alarm probability than the subspace-based UID in the multipath channels. However, from our analysis, increasing the order m does not improve the performance. Therefore, when m is one, the performance of the new detector is maximal.

  8. NEW VERSATILE CAMERA CALIBRATION TECHNIQUE BASED ON LINEAR RECTIFICATION

    Institute of Scientific and Technical Information of China (English)

    Pan Feng; Wang Xuanyin

    2004-01-01

    A new versatile camera calibration technique for machine vision using off-the-shelf cameras is described. Aimed at the large distortion of the off-the-shelf cameras, a new camera distortion rectification technology based on line-rectification is proposed. A full-camera-distortion model is introduced and a linear algorithm is provided to obtain the solution. After the camera rectification intrinsic and extrinsic parameters are obtained based on the relationship between the homograph and absolute conic. This technology needs neither a high-accuracy three-dimensional calibration block, nor a complicated translation or rotation platform. Both simulations and experiments show that this method is effective and robust.

  9. The role of ultrasound elastographic techniques in chronic liver disease: Current status and future perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Piscaglia, Fabio, E-mail: fabio.piscaglia@unibo.it [Division of Internal Medicine, University of Bologna, General and University Hospital S. Orsola-Malpighi, Bologna (Italy); Marinelli, Sara, E-mail: sara_marinelli@libero.it [Division of Internal Medicine, University of Bologna, General and University Hospital S. Orsola-Malpighi, Bologna (Italy); Bota, Simona, E-mail: bota_simona1982@yahoo.com [Department of Gastroenterology and Hepatology, University of Medicine and Pharmacy “Victor Babeş”, Timişoara (Romania); Serra, Carla, E-mail: carla.serra@aosp.bo.it [Division of Medical Liver Transplant Care, General and University Hospital S. Orsola-Malpighi, Bologna (Italy); Venerandi, Laura, E-mail: laura.venerandi@gmail.com [Division of Internal Medicine, University of Bologna, General and University Hospital S. Orsola-Malpighi, Bologna (Italy); Leoni, Simona, E-mail: leonisimona@yahoo.it [Division of Internal Medicine, University of Bologna, General and University Hospital S. Orsola-Malpighi, Bologna (Italy); Salvatore, Veronica, E-mail: veronica.salvatore@unibo.it [Division of Internal Medicine, University of Bologna, General and University Hospital S. Orsola-Malpighi, Bologna (Italy)

    2014-03-15

    This review illustrates the state of the art clinical applications and the future perspectives of ultrasound elastographic methods for the evaluation of chronic liver diseases, including the most widely used and validated technique, transient elastography, followed by shear wave elastography and strain imaging elastography. Liver ultrasound elastography allows the non-invasive evaluation of liver stiffness, providing information regarding the stage of fibrosis, comparable to liver biopsy which is still considered the gold standard; in this way, it can help physicians in managing patients, including the decision as to when to start antiviral treatment. The characterization of focal liver lesions and the prognostic role of the elastographic technique in the prediction of complications of cirrhosis are still under investigation.

  10. Average OH density in alternating current dielectric barrier discharge by laser-induced fluorescence technique

    Science.gov (United States)

    Yang, Hongliang; Feng, Chunlei; Gao, Liang; Ding, Hongbin

    2015-10-01

    The average OH density in atmospheric He-H2O(0.4%) needle-plate dielectric barrier discharge (DBD) was measured by the asynchronous laser-induced fluorescence (LIF) technique and the fluctuation of OH radical density was measured simultaneously to prove that the average OH density can be obtained by the asynchronous LIF technique. The evolution of the average OH density in four different discharge patterns, namely, negative barrier corona discharge, glow discharge, multi glow discharge, and streamer discharge, was studied, and it was found that the average OH density has an observable increase from corona discharge to streamer discharge. The main mechanism of OH production in the four different discharge patterns was analyzed. It was shown that the main mechanism of OH production in negative barrier corona discharge is electron direct collision dissociation, whereas in the other three discharge patterns the He metastable Penning ionization is the main process.

  11. Artificial chordae for degenerative mitral valve disease: critical analysis of current techniques

    Science.gov (United States)

    Ibrahim, Michael; Rao, Christopher; Athanasiou, Thanos

    2012-01-01

    The surgical repair of degenerative mitral valve disease involves a number of technical points of importance. The use of artificial chordae for the repair of degenerative disease has increased as a part of the move from mitral valve replacement to repair of the mitral valve. The use of artificial chordae provides an alternative to the techniques pioneered by Carpentier (including the quadrangular resection, transfer of native chordae and papillary muscle shortening/plasty), which can be more technically difficult. Despite a growth in their uptake and the indications for their use, a number of challenges remain for the use of artificial chordae in mitral valve repair, particularly in the determination of the correct length to ensure optimal leaflet coaptation. Here, we analyse over 40 techniques described for artificial chordae mitral valve repair in the setting of degenerative disease. PMID:22962321

  12. Green Aspects of Techniques for the Determination of Currently Used Pesticides in Environmental Samples

    Directory of Open Access Journals (Sweden)

    Maciej Tankiewicz

    2011-11-01

    Full Text Available Pesticides are among the most dangerous environmental pollutants because of their stability, mobility and long-term effects on living organisms. Their presence in the environment is a particular danger. It is therefore crucial to monitor pesticide residues using all available analytical methods. The analysis of environmental samples for the presence of pesticides is very difficult: the processes involved in sample preparation are labor-intensive and time-consuming. To date, it has been standard practice to use large quantities of organic solvents in the sample preparation process; but as these solvents are themselves hazardous, solvent-less and solvent-minimized techniques are becoming popular. The application of Green Chemistry principles to sample preparation is primarily leading to the miniaturization of procedures and the use of solvent-less techniques, and these are discussed in the paper.

  13. DDoS Attack and Defense: Review of Some Traditional and Current Techniques

    OpenAIRE

    Aamir, Muhammad; ZAIDI, Mustafa Ali

    2014-01-01

    Distributed Denial of Service (DDoS) attacks exhaust victim's bandwidth or services. Traditional architecture of Internet is vulnerable to DDoS attacks and an ongoing cycle of attack & defense is observed. In this paper, different types and techniques of DDoS attacks and their countermeasures are reviewed. The significance of this paper is the coverage of many aspects of countering DDoS attacks including new research on the topic. We survey different papers describing methods of defense again...

  14. Review of current status of high flux heat transfer techniques. Volume I. Text + Appendix A

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, W.H.; Gordon, H.S.; Lackner, H.; Mettling, J.R.; Miller, J.E.

    1980-09-01

    The scope of this work comprised two tasks. The first was to review high heat flux technology with consideration given to heat transfer panel configuration, diagnostics techniques and coolant supply. The second task was to prepare a report describing the findings of the review, to recommend the technology offering the least uncertainty for scale-up for the MFTF-B requirement and to recommend any new or perceived requirements for R and D effort.

  15. Shoulder arthroplasty in osteoarthritis: current concepts in biomechanics and surgical technique

    OpenAIRE

    MEROLLA, GIOVANNI; Nastrucci, Guglielmo; Porcellini, Giuseppe

    2013-01-01

    Shoulder arthroplasty is a technically demanding procedure to restore shoulder function in patients with severe osteoarthritis of the glenohumeral joint. The modern prosthetic system exploit the benefits of modularity and the availibility of additional sizes of the prosthetic components. In this paper we describe the biomechanics of shoulder arthroplasty and the technique for shoulder replacement including total shoulder arthroplasty (TSA) with all-polyethylene and metal-backed glenoid compon...

  16. A Different Web-Based Geocoding Service Using Fuzzy Techniques

    Science.gov (United States)

    Pahlavani, P.; Abbaspour, R. A.; Zare Zadiny, A.

    2015-12-01

    Geocoding - the process of finding position based on descriptive data such as address or postal code - is considered as one of the most commonly used spatial analyses. Many online map providers such as Google Maps, Bing Maps and Yahoo Maps present geocoding as one of their basic capabilities. Despite the diversity of geocoding services, users usually face some limitations when they use available online geocoding services. In existing geocoding services, proximity and nearness concept is not modelled appropriately as well as these services search address only by address matching based on descriptive data. In addition there are also some limitations in display searching results. Resolving these limitations can enhance efficiency of the existing geocoding services. This paper proposes the idea of integrating fuzzy technique with geocoding process to resolve these limitations. In order to implement the proposed method, a web-based system is designed. In proposed method, nearness to places is defined by fuzzy membership functions and multiple fuzzy distance maps are created. Then these fuzzy distance maps are integrated using fuzzy overlay technique for obtain the results. Proposed methods provides different capabilities for users such as ability to search multi-part addresses, searching places based on their location, non-point representation of results as well as displaying search results based on their priority.

  17. A DIFFERENT WEB-BASED GEOCODING SERVICE USING FUZZY TECHNIQUES

    Directory of Open Access Journals (Sweden)

    P. Pahlavani

    2015-12-01

    Full Text Available Geocoding – the process of finding position based on descriptive data such as address or postal code - is considered as one of the most commonly used spatial analyses. Many online map providers such as Google Maps, Bing Maps and Yahoo Maps present geocoding as one of their basic capabilities. Despite the diversity of geocoding services, users usually face some limitations when they use available online geocoding services. In existing geocoding services, proximity and nearness concept is not modelled appropriately as well as these services search address only by address matching based on descriptive data. In addition there are also some limitations in display searching results. Resolving these limitations can enhance efficiency of the existing geocoding services. This paper proposes the idea of integrating fuzzy technique with geocoding process to resolve these limitations. In order to implement the proposed method, a web-based system is designed. In proposed method, nearness to places is defined by fuzzy membership functions and multiple fuzzy distance maps are created. Then these fuzzy distance maps are integrated using fuzzy overlay technique for obtain the results. Proposed methods provides different capabilities for users such as ability to search multi-part addresses, searching places based on their location, non-point representation of results as well as displaying search results based on their priority.

  18. Techniques of tumour bed boost irradiation in breast conserving therapy: Current evidence and suggested guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, Rakesh; Singh, Suruchi; Budrukkar, Ashwini [Tata Memorial Hospital, Mumbai (India)

    2007-10-15

    Breast conservation surgery followed by external beam radiotherapy to breast has become the standard of care in management of early carcinoma breast. A boost to the tumour bed after whole breast radiotherapy is employed in view of the pattern of tumour bed recurrences in the index quadrant and was particularly considered in patients with some adverse histopathological characteristics such as positive margins, extensive intraductal carcinoma (EIC), lymphovascular invasion (LVI), etc. There is however, now, a conclusive evidence of improvement in local control rates after a boost radiotherapy dose in patients even without such factors and for all age groups. The maximum absolute reduction of local recurrences by the addition of boost is especially seen in young premenopausal patients. At the same time, the addition of boost is associated with increased risk of worsening of cosmesis and no clear cut survival advantage. Radiological modalities such as fluoroscopy, ultrasound and CT scan have aided in accurate delineation of tumour bed with increasing efficacy. A widespread application of these techniques might ultimately translate into improved local control with minimal cosmetic deficit. The present article discusses the role of radiotherapy boost and the means to delineate and deliver the same, identify the high risk group, optimal technique and the doses and fractionations to be used. It also discusses the extent of adverse cosmetic outcome after boost delivery, means to minimise it and relevance of tumour bed in present day scenario of advanced radiotherapy delivery techniques like (IMRT)

  19. Current state-of-the-art of contouring techniques in manufacturing

    Science.gov (United States)

    Harding, Kevin G.

    1990-10-01

    A manager with a major automobile manufacturer once made the comment that " the best thing we ever did to improve quality was give the guys on the floor a caliper to measure the parts" . As the tolerances on manufacturing become tighter the need for accurate measurement has also increased. Hand fitting of parts to each other does not work in modem automated factories. Gages in the past have been built to provide a fixed set of measurements of a known part. This practice too has been changing due to the trend toward flexible manufacturing. Now the gages themselves must be flexible to accommodate the variety of parts made on a single line. This need has spurred a flurry of activity in the development of new three-dimensional (3-D) measurement tools. This paper will review the current state of the new optical based 3-D tools and discuss some of the applications being addressed. Background The need for three dimensional contouring has arisen from two primary areas of application. The first area of application has been in the area of robot guidance. ''4 Robots are used for their flexibility of motion. Applications may include loading of parts into machine tools stuffing printed circuit boards welding and cutting metal or simple assembly operations. In the simple applications the motion of the robot can be preprogrammed to follow a set trajectory. If the part not in the right location then the operation fails. In the case of painting robots this preprogrammed route can generally taken. As the task gets more complex and the positions become more critical guidance of the robot becomes important. If a robot welder misses the seam it may not only not make the weld but may also damage the surrounding material. This area of robot guidance has been one of the primary areas of growing interest. 58 The requirements for this type of application do not demand a great deal of contour measurement but does require three dimensional information. The range to the seam being welded as

  20. Nasal base narrowing: the alar flap advancement technique.

    Science.gov (United States)

    Ismail, Ahmed Soliman

    2011-01-01

    To evaluate the role of creating an alar-based advancement flap in narrowing the nasal base and correcting excessive alar flare. Case series with chart review. This is a retrospective record review study. The study included 35 cases presenting with a wide nasal base and excessive alar flaring. The surgical procedure combined the alar base reduction with alar flare excision by creating a single laterally based alar flap. Any caudal septal deformities and any nasal tip modification procedures were corrected before the nasal base narrowing. The mean follow-up period was 23 months. The mean alar flap narrowing was 6.3 mm, whereas the mean width of sill narrowing was 2.9 mm. This single laterally based advancement alar flap resulted in a more conservative external resection, thus avoiding alar wedge overresection or blunting of the alar-facial crease. No cases of postoperative bleeding, infection, or keloid were encountered, and the external alar wedge excision healed with no apparent scar that was hidden in the depth of the alar-facial crease. The risk of notching of the alar rim at the sill incision is reduced by adopting a 2-layer closure of the vestibular floor. The alar base advancement flap is an effective technique in narrowing both the nasal base and excessive alar flare. It adopts a single skin excision to correct the 2 deformities while commonly feared complications were avoided.

  1. Passivity-based control technique for integration of DG resources into the power grid

    DEFF Research Database (Denmark)

    Mehrasa, Majid; Adabi, M. Ebrahim; Pouresmaeil, Edris

    2014-01-01

    This paper deals with a control method for integration of Distributed Generation (DG) sources to the power grid. The proposed control strategy has been designed based on passivity technique and provides compensation for the active, reactive, and harmonic current components of loads during...... for the d and q axis in the control loop of DG, which are defined based on the objectives of proposed method. The effectiveness of the proposed control scheme is validated with injection of maximum available power from the DG resources to the power grid, correction of power factor between the grid current...... the connection of DG link to the grid. The proper switching functions of interfaced converter have been defined based on the passivity method through the achieving space equations and suitable series damping injection. The proposed control plan is completed by setting suitable reference current components...

  2. Evaluation of paint coating thickness variations based on pulsed Infrared thermography laser technique

    Science.gov (United States)

    Mezghani, S.; Perrin, E.; Vrabie, V.; Bodnar, J. L.; Marthe, J.; Cauwe, B.

    2016-05-01

    In this paper, a pulsed Infrared thermography technique using a homogeneous heat provided by a laser source is used for the non-destructive evaluation of paint coating thickness variations. Firstly, numerical simulations of the thermal response of a paint coated sample are performed. By analyzing the thermal responses as a function of thermal properties and thickness of both coating and substrate layers, optimal excitation parameters of the heating source are determined. Two characteristic parameters were studied with respect to the paint coating layer thickness variations. Results obtained using an experimental test bench based on the pulsed Infrared thermography laser technique are compared with those given by a classical Eddy current technique for paint coating variations from 5 to 130 μm. These results demonstrate the efficiency of this approach and suggest that the pulsed Infrared thermography technique presents good perspectives to characterize the heterogeneity of paint coating on large scale samples with other heating sources.

  3. Performance Based Novel Techniques for Semantic Web Mining

    Directory of Open Access Journals (Sweden)

    Mahendra Thakur

    2012-01-01

    Full Text Available The explosive growth in the size and use of the World Wide Web continuously creates new great challenges and needs. The need for predicting the users preferences in order to expedite and improve the browsing though a site can be achieved through personalizing of the websites. Most of the research efforts in web personalization correspond to the evolution of extensive research in web usage mining, i.e. the exploitation of the navigational patterns of the web site visitors. When a personalization system relies solely on usage-based results, however, valuable information conceptually related to what is finally recommended may be missed. Moreover, the structural properties of the web site are often disregarded. In this paper, we propose novel techniques that use the content semantics and the structural properties of a web site in order to improve the effectiveness of web personalization. In the first part of our work we present standing for Semantic Web Personalization, a personalization system that integrates usage data with content semantics, expressed in ontology terms, in order to compute semantically enhanced navigational patterns and effectively generate useful recommendations. To the best of our knowledge, our proposed technique is the only semantic web personalization system that may be used by non-semantic web sites. In the second part of our work, we present a novel approach for enhancing the quality of recommendations based on the underlying structure of a web site. We introduce UPR (Usage-based PageRank, a PageRank-style algorithm that relies on the recorded usage data and link analysis techniques. Overall, we demonstrate that our proposed hybrid personalization framework results in more objective and representative predictions than existing techniques.

  4. Laser image denoising technique based on multi-fractal theory

    Science.gov (United States)

    Du, Lin; Sun, Huayan; Tian, Weiqing; Wang, Shuai

    2014-02-01

    The noise of laser images is complex, which includes additive noise and multiplicative noise. Considering the features of laser images, the basic processing capacity and defects of the common algorithm, this paper introduces the fractal theory into the research of laser image denoising. The research of laser image denoising is implemented mainly through the analysis of the singularity exponent of each pixel in fractal space and the feature of multi-fractal spectrum. According to the quantitative and qualitative evaluation of the processed image, the laser image processing technique based on fractal theory not only effectively removes the complicated noise of the laser images obtained by range-gated laser active imaging system, but can also maintains the detail information when implementing the image denoising processing. For different laser images, multi-fractal denoising technique can increase SNR of the laser image at least 1~2dB compared with other denoising techniques, which basically meet the needs of the laser image denoising technique.

  5. Regression based peak load forecasting using a transformation technique

    Energy Technology Data Exchange (ETDEWEB)

    Haida, Takeshi; Muto, Shoichi (Tokyo Electric Power Co. (Japan). Computer and Communication Research Center)

    1994-11-01

    This paper presents a regression based daily peak load forecasting method with a transformation technique. In order to forecast the load precisely through a year, the authors should consider seasonal load change, annual load growth and the latest daily load change. To deal with these characteristics in the load forecasting, a transformation technique is presented. This technique consists of a transformation function with translation and reflection methods. The transformation function is estimated with the previous year's data points, in order that the function converts the data points into a set of new data points with preserving the shape of temperature-load relationships in the previous year. Then, the function is slightly translated so that the transformed data points will fit the shape of temperature-load relationships in the year. Finally, multivariate regression analysis with the latest daily loads and weather observations estimates the forecasting model. Large forecasting errors caused by the weather-load nonlinear characteristic in the transitional seasons such as spring and fall are reduced. Performance of the technique which is verified with simulations on actual load data of Tokyo Electric Power Company is also described.

  6. Calculation technique for special tank capacity based on setting-out

    Science.gov (United States)

    Fan, Bai-xing; Li, Zong-chun; Li, Guang-yun; Sun, Qing-wen

    2008-12-01

    Special tanks are important for energy source storage and transport. Based on the research of current calculation techniques for special tank capacity, a new principle and technique for special tank capacity calculations is discussed, which converts the capacity calculation into setting out and sets up a tank coordinate system. It completes all the work with a surveying robot online control mode. The new technology can calculate the tank capacity fast and precise and avoids the disadvantage of traditional measurement technology. Furthermore, special a software system is compiled, which can measure, calculate, adjust and create report tables automatically. Finally, the measurement accuracy and efficiency of the measured data are analyzed.

  7. Noninvasive in vivo glucose sensing using an iris based technique

    Science.gov (United States)

    Webb, Anthony J.; Cameron, Brent D.

    2011-03-01

    Physiological glucose monitoring is important aspect in the treatment of individuals afflicted with diabetes mellitus. Although invasive techniques for glucose monitoring are widely available, it would be very beneficial to make such measurements in a noninvasive manner. In this study, a New Zealand White (NZW) rabbit animal model was utilized to evaluate a developed iris-based imaging technique for the in vivo measurement of physiological glucose concentration. The animals were anesthetized with isoflurane and an insulin/dextrose protocol was used to control blood glucose concentration. To further help restrict eye movement, a developed ocular fixation device was used. During the experimental time frame, near infrared illuminated iris images were acquired along with corresponding discrete blood glucose measurements taken with a handheld glucometer. Calibration was performed using an image based Partial Least Squares (PLS) technique. Independent validation was also performed to assess model performance along with Clarke Error Grid Analysis (CEGA). Initial validation results were promising and show that a high percentage of the predicted glucose concentrations are within 20% of the reference values.

  8. IMAGE SEGMENTATION BASED ON MARKOV RANDOM FIELD AND WATERSHED TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    纳瑟; 刘重庆

    2002-01-01

    This paper presented a method that incorporates Markov Random Field(MRF), watershed segmentation and merging techniques for performing image segmentation and edge detection tasks. MRF is used to obtain an initial estimate of x regions in the image under process where in MRF model, gray level x, at pixel location i, in an image X, depends on the gray levels of neighboring pixels. The process needs an initial segmented result. An initial segmentation is got based on K-means clustering technique and the minimum distance, then the region process in modeled by MRF to obtain an image contains different intensity regions. Starting from this we calculate the gradient values of that image and then employ a watershed technique. When using MRF method it obtains an image that has different intensity regions and has all the edge and region information, then it improves the segmentation result by superimpose closed and an accurate boundary of each region using watershed algorithm. After all pixels of the segmented regions have been processed, a map of primitive region with edges is generated. Finally, a merge process based on averaged mean values is employed. The final segmentation and edge detection result is one closed boundary per actual region in the image.

  9. Elbow hemiarthroplasty for the management of distal humeral fractures: current technique, indications and results

    OpenAIRE

    Phadnis, Joideep; Adam C. Watts; Bain, Gregory I

    2016-01-01

    There has been a growing recent interest in the use of elbow hemiarthroplasty for the treatment of distal humeral trauma in select patients. However, the current available evidence regarding outcome after elbow hemiarthroplasty is limited to case series and biomechanical data. Consequently, the procedure remains unfamiliar to many surgeons. The aim of the present review is to outline the evidence regarding elbow hemiarthroplasty and to use this, along with the author’s experience, to better d...

  10. Application of a Lamb waves based technique for structural health monitoring of GFRP undercyclic loading

    OpenAIRE

    Eremin, Alexandr Vyacheslavovich; Byakov, Anton Viktorovich; Panin, Sergey Viktorovich; Burkov, Mikhail Vladimirovich; Lyubutin, Pavel Stepanovich; Sunder, R.

    2016-01-01

    A Lamb wave based ultrasonic technique as well as optical image characterization was utilized to estimate a current mechanical state of glass fiber reinforced polymers (GFRP) under cyclic tension. The ultrasonic acoustic method was applied in a 'pitch-catch' mode using piezoelectric transducers adhesively bonded onto a specimen surface. Numerical evaluation of acoustic data was performed by calculating two informative parameters: maximum of amplitude of the received signal and variance of sig...

  11. Efficient Identification Using a Prime-Feature-Based Technique

    DEFF Research Database (Denmark)

    Hussain, Dil Muhammad Akbar; Haq, Shaiq A.; Valente, Andrea

    2011-01-01

    Identification of authorized train drivers through biometrics is a growing area of interest in locomotive radio remote control systems. The existing technique of password authentication is not very reliable and potentially unauthorized personnel may also operate the system on behalf of the operator....... Fingerprint identification system, implemented on PC/104 based real-time systems, can accurately identify the operator. Traditionally, the uniqueness of a fingerprint is determined by the overall pattern of ridges and valleys as well as the local ridge anomalies e.g., a ridge bifurcation or a ridge ending...... in this paper. The technique involves identifying the most prominent feature of the fingerprint and searching only for that feature in the database to expedite the search process. The proposed architect provides efficient matching process and indexing feature for identification is unique....

  12. An Improved Face Recognition Technique Based on Modular LPCA Approach

    Directory of Open Access Journals (Sweden)

    Mathu S.S. Kumar

    2011-01-01

    Full Text Available Problem statement: A face identification algorithm based on modular localized variation by Eigen Subspace technique, also called modular localized principal component analysis, is presented in this study. Approach: The face imagery was partitioned into smaller sub-divisions from a predefined neighborhood and they were ultimately fused to acquire many sets of features. Since a few of the normal facial features of an individual do not differ even when the pose and illumination may differ, the proposed method manages these variations. Results: The proposed feature selection module has significantly, enhanced the identification precision using standard face databases when compared to conservative and modular PCA techniques. Conclusion: The proposed algorithm, when related with conservative PCA algorithm and modular PCA, has enhanced recognition accuracy for face imagery with illumination, expression and pose variations.

  13. Novel synchrotron based techniques for characterization of energy materials

    Energy Technology Data Exchange (ETDEWEB)

    Poulsen, H.F.; Nielsen, S.F.; Olsen, U.L.; Schmidt, S. (Risoe DTU, Materials Research Dept., Roskilde (Denmark)); Wright, J. (European Synchrotron Radiation Facility, Grenoble Cedex (France))

    2008-10-15

    Two synchrotron techniques are reviewed, both based on the use of high energy x-rays, and both applicable to in situ studies of bulk materials. Firstly, 3DXRD microscopy, which enables 3D characterization of the position, morphology, phase, elastic strain and crystallographic orientation of the individual embedded grains in polycrystalline specimens. In favourable cases, hundreds of grains can be studied simultaneously during processing. Secondly, plastic strain tomography: a unique method for determining the plastic strain field within materials during processing the potential applications of these techniques for basic and applied studies of four types of energy materials are discussed: polymer composites for wind turbines, solid oxide fuel cells, hydrogen storage materials and superconducting tapes. Furthermore, progress on new detectors aiming at improving the spatial and temporal resolution of such measurements is described. (au)

  14. New modulation-based watermarking technique for video

    Science.gov (United States)

    Lemma, Aweke; van der Veen, Michiel; Celik, Mehmet

    2006-02-01

    Successful watermarking algorithms have already been developed for various applications ranging from meta-data tagging to forensic tracking. Nevertheless, it is commendable to develop alternative watermarking techniques that provide a broader basis for meeting emerging services, usage models and security threats. To this end, we propose a new multiplicative watermarking technique for video, which is based on the principles of our successful MASK audio watermark. Audio-MASK has embedded the watermark by modulating the short-time envelope of the audio signal and performed detection using a simple envelope detector followed by a SPOMF (symmetrical phase-only matched filter). Video-MASK takes a similar approach and modulates the image luminance envelope. In addition, it incorporates a simple model to account for the luminance sensitivity of the HVS (human visual system). Preliminary tests show algorithms transparency and robustness to lossy compression.

  15. A VIKOR Technique with Applications Based on DEMATEL and ANP

    Science.gov (United States)

    Ou Yang, Yu-Ping; Shieh, How-Ming; Tzeng, Gwo-Hshiung

    In multiple criteria decision making (MCDM) methods, the compromise ranking method (named VIKOR) was introduced as one applicable technique to implement within MCDM. It was developed for multicriteria optimization of complex systems. However, few papers discuss conflicting (competing) criteria with dependence and feedback in the compromise solution method. Therefore, this study proposes and provides applications for a novel model using the VIKOR technique based on DEMATEL and the ANP to solve the problem of conflicting criteria with dependence and feedback. In addition, this research also uses DEMATEL to normalize the unweighted supermatrix of the ANP to suit the real world. An example is also presented to illustrate the proposed method with applications thereof. The results show the proposed method is suitable and effective in real-world applications.

  16. New Intellectual Economized Technique on Electricity Based on DSP

    Institute of Scientific and Technical Information of China (English)

    Chang-ming LI; Tao JI; Ying SUN

    2010-01-01

    In order to resolve the problem of the unbalanced threephase and unstable voltage,intellectual economized technique on electricity based on electromagnetic regulation and control is proposed in this paper.We choose the TMS320LF2407A as the control chip and stepper motor as the executing agency.The equipment controls the movable contact reaching to the assigned position on the magnetic coil quickly and accurately,and outputs the sine-wave voltage steadily along with the network voltage variation though the fuzzy Porpornonal Integral Derivative(PID)control algorithm of integral separation and incremental mode with setting dead area.The principle of work and the key technique on the electromagnetic regulation and control are introduced in detail in this paper.The experiment result gives a proof for all the algorithm mentioned in this paper.

  17. Endoscopic button gastrostomy: Comparing a sutured endoscopic approach to the current techniques.

    Science.gov (United States)

    Gonzalez-Hernandez, Jessica; Daoud, Yahya; Fischer, Anne C; Barth, Bradley; Piper, Hannah G

    2016-01-01

    Button gastrostomy is the preferred feeding device in children and can be placed open or laparoscopically (LBG). Alternatively, a percutaneous endoscopic gastrostomy (PEG) can be placed initially and exchanged for a button. Endoscopic-assisted button gastrostomy (EBG) combines both techniques, using only one incision and suturing the stomach to the abdominal wall. The long-term outcomes and potential costs for EBG were compared to other techniques. Children undergoing EBG, LBG, and PEG (2010-2013) were compared. Patient demographics, procedure duration/complications, and clinic and emergency room (ER) visits for an eight-week follow-up period were compared. Patient demographics were similar (32 patients/group). Mean procedure time (min) for EBG was 38 ± 9, compared to 58 ± 20 for LBG and 31 ± 10 for PEG (pbutton gastrostomy. EBG is safe and comparable to LBG and PEG in terms of complications. It has a shorter procedure time than LBG and does not require laparoscopy, device exchange, or subsequent fluoroscopic confirmation, potentially reducing costs. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Cranial electrotherapy stimulation and transcranial pulsed current stimulation: a computer based high-resolution modeling study.

    Science.gov (United States)

    Datta, Abhishek; Dmochowski, Jacek P; Guleyupoglu, Berkan; Bikson, Marom; Fregni, Felipe

    2013-01-15

    The field of non-invasive brain stimulation has developed significantly over the last two decades. Though two techniques of noninvasive brain stimulation--transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS)--are becoming established tools for research in neuroscience and for some clinical applications, related techniques that also show some promising clinical results have not been developed at the same pace. One of these related techniques is cranial electrotherapy stimulation (CES), a class of transcranial pulsed current stimulation (tPCS). In order to understand further the mechanisms of CES, we aimed to model CES using a magnetic resonance imaging (MRI)-derived finite element head model including cortical and also subcortical structures. Cortical electric field (current density) peak intensities and distributions were analyzed. We evaluated different electrode configurations of CES including in-ear and over-ear montages. Our results confirm that significant amounts of current pass the skull and reach cortical and subcortical structures. In addition, depending on the montage, induced currents at subcortical areas, such as midbrain, pons, thalamus and hypothalamus are of similar magnitude than that of cortical areas. Incremental variations of electrode position on the head surface also influence which cortical regions are modulated. The high-resolution modeling predictions suggest that details of electrode montage influence current flow through superficial and deep structures. Finally we present laptop based methods for tPCS dose design using dominant frequency and spherical models. These modeling predictions and tools are the first step to advance rational and optimized use of tPCS and CES.

  19. Feature-based multiresolution techniques for product design

    Institute of Scientific and Technical Information of China (English)

    LEE Sang Hun; LEE Kunwoo

    2006-01-01

    3D computer-aided design (CAD) systems based on feature-based solid modelling technique have been widely spread and used for product design. However, when part models associated with features are used in various downstream applications,simplified models in various levels of detail (LODs) are frequently more desirable than the full details of the parts. In particular,the need for feature-based multiresolution representation of a solid model representing an object at multiple LODs in the feature unit is increasing for engineering tasks. One challenge is to generate valid models at various LODs after an arbitrary rearrangement of features using a certain LOD criterion, because composite Boolean operations consisting of union and subtraction are not commutative. The other challenges are to devise proper topological framework for multiresolution representation, to suggest more reasonable LOD criteria, and to extend applications. This paper surveys the recent research on these issues.

  20. Advanced computer techniques for inverse modeling of electric current in cardiac tissue

    Energy Technology Data Exchange (ETDEWEB)

    Hutchinson, S.A.; Romero, L.A.; Diegert, C.F.

    1996-08-01

    For many years, ECG`s and vector cardiograms have been the tools of choice for non-invasive diagnosis of cardiac conduction problems, such as found in reentrant tachycardia or Wolff-Parkinson-White (WPW) syndrome. Through skillful analysis of these skin-surface measurements of cardiac generated electric currents, a physician can deduce the general location of heart conduction irregularities. Using a combination of high-fidelity geometry modeling, advanced mathematical algorithms and massively parallel computing, Sandia`s approach would provide much more accurate information and thus allow the physician to pinpoint the source of an arrhythmia or abnormal conduction pathway.

  1. Chosen Aspects Of Investigations Of Solar Cells With The Laser Beam Induced Current Technique

    Directory of Open Access Journals (Sweden)

    Chrobak Łukasz Bartłomiej

    2015-06-01

    Full Text Available This paper presents maps of spatial distributions of the short circuit current Isc(x,y and the open circuit voltage Uoc(x,y of the investigated low cost solar cells. Visible differences in values of these parameters were explained by differences in the serial and shunt resistances determined for different points of solar cells from measurements of I–V characteristics. The spectral dependence of the photo voltage of solar cell is also shown, discussed and interpreted in the model of amorphous and crystal silicon.

  2. Current techniques in the performance, interpretation, and reporting of CT colonography.

    Science.gov (United States)

    Poullos, Peter D; Beaulieu, Christopher F

    2010-04-01

    The technical objective of computed tomographic colonography (CTC) is to acquire high-quality computed tomography images of the cleansed, well-distended colon for polyp detection. In this article the authors provide an overview of the technical components of CTC, from preparation of the patient to acquisition of the imaging data and basic methods of interpretation. In each section, the best evidence for current practices and recommendations is reviewed. Each of the technical components must be optimized to achieve high sensitivity in polyp detection.

  3. Current State of Value-Based Purchasing Programs.

    Science.gov (United States)

    Chee, Tingyin T; Ryan, Andrew M; Wasfy, Jason H; Borden, William B

    2016-05-31

    The US healthcare system is rapidly moving toward rewarding value. Recent legislation, such as the Affordable Care Act and the Medicare Access and CHIP Reauthorization Act, solidified the role of value-based payment in Medicare. Many private insurers are following Medicare's lead. Much of the policy attention has been on programs such as accountable care organizations and bundled payments; yet, value-based purchasing (VBP) or pay-for-performance, defined as providers being paid fee-for-service with payment adjustments up or down based on value metrics, remains a core element of value payment in Medicare Access and CHIP Reauthorization Act and will likely remain so for the foreseeable future. This review article summarizes the current state of VBP programs and provides analysis of the strengths, weaknesses, and opportunities for the future. Multiple inpatient and outpatient VBP programs have been implemented and evaluated; the impact of those programs has been marginal. Opportunities to enhance the performance of VBP programs include improving the quality measurement science, strengthening both the size and design of incentives, reducing health disparities, establishing broad outcome measurement, choosing appropriate comparison targets, and determining the optimal role of VBP relative to alternative payment models. VBP programs will play a significant role in healthcare delivery for years to come, and they serve as an opportunity for providers to build the infrastructure needed for value-oriented care.

  4. Current techniques for high-resolution mapping of behavioral circuits in Drosophila.

    Science.gov (United States)

    Sivanantharajah, Lovesha; Zhang, Bing

    2015-09-01

    Understanding behavior requires unraveling the mysteries of neurons, glia, and their extensive connectivity. Drosophila has emerged as an excellent organism for studying the neural basis of behavior. This can be largely attributed to the extensive effort of the fly community to develop numerous sophisticated genetic tools for visualizing, mapping, and manipulating behavioral circuits. Here, we attempt to highlight some of the new reagents, techniques and approaches available for dissecting behavioral circuits in Drosophila. We focus on detailing intersectional strategies such as the Flippase-induced intersectional Gal80/Gal4 repression (FINGR), because of the tremendous potential they possess for mapping the minimal number of cells required for a particular behavior. The logic and strategies outlined in this review should have broad applications for other genetic model organisms.

  5. The edge transient-current technique (E-TCT) with high energy hadron beam

    Science.gov (United States)

    Gorišek, Andrej; Cindro, Vladimir; Kramberger, Gregor; Mandić, Igor; Mikuž, Marko; Muškinja, Miha; Zavrtanik, Marko

    2016-09-01

    We propose a novel way to investigate the properties of silicon and CVD diamond detectors for High Energy Physics experiments complementary to the already well-established E-TCT technique using laser beam. In the proposed setup the beam of high energy hadrons (MIPs) is used instead of laser beam. MIPs incident on the detector in the direction parallel to the readout electrode plane and perpendicular to the edge of the detector. Such experiment could prove very useful to study CVD diamond detectors that are almost inaccessible for the E-TCT measurements with laser due to large band-gap as well as to verify and complement the E-TCT measurements of silicon. The method proposed is being tested at CERN in a beam of 120 GeV hadrons using a reference telescope with track resolution at the DUT of few μm. The preliminary results of the measurements are presented.

  6. Non-Invasive Glucose Monitoring Techniques: A review and current trends

    CERN Document Server

    Poddar, Raju; Shukla, Pratyoosh; Sen, Pratima

    2008-01-01

    Diabetes mellitus is a complex group of syndromes that have in common a disturbance in the body's use of glucose, resulting in an elevated blood sugar. Once detected, sugar diabetes can be controlled by an appropriate regimen that should include diet therapy, a weight reduction program for those persons who are overweight, a program of exercise and insulin injections or oral drugs to lower blood glucose. Blood glucose monitoring by the patient and the physician is an important aspect in the control of the devastating complications (heart disease, blindness, kidney failure or amputations) due to the disease. Intensive therapy and frequent glucose testing has numerous benefits. With ever improving advances in diagnostic technology, the race for the next generation of bloodless, painless, accurate glucose instruments has begun. In this paper, we reviewed various methods, techniques and approaches successfully demonstrated for measuring or monitoring blood glucose. Invasive, minimally invasive and noninvasive tec...

  7. The edge transient-current technique (E-TCT) with high energy hadron beam

    Energy Technology Data Exchange (ETDEWEB)

    Gorišek, Andrej; Cindro, Vladimir; Kramberger, Gregor; Mandić, Igor [J. Stefan Institute, Ljubljana (Slovenia); Mikuž, Marko [J. Stefan Institute, Ljubljana (Slovenia); University of Ljubljana (Slovenia); Muškinja, Miha; Zavrtanik, Marko [J. Stefan Institute, Ljubljana (Slovenia)

    2016-09-21

    We propose a novel way to investigate the properties of silicon and CVD diamond detectors for High Energy Physics experiments complementary to the already well-established E-TCT technique using laser beam. In the proposed setup the beam of high energy hadrons (MIPs) is used instead of laser beam. MIPs incident on the detector in the direction parallel to the readout electrode plane and perpendicular to the edge of the detector. Such experiment could prove very useful to study CVD diamond detectors that are almost inaccessible for the E-TCT measurements with laser due to large band-gap as well as to verify and complement the E-TCT measurements of silicon. The method proposed is being tested at CERN in a beam of 120 GeV hadrons using a reference telescope with track resolution at the DUT of few μm. The preliminary results of the measurements are presented.

  8. A Generic Current Mode Design for Multifunction Grounded Capacitor Filters Employing Log-Domain Technique

    Directory of Open Access Journals (Sweden)

    N. A. Shah

    2011-01-01

    Full Text Available A generic design (GD for realizing an nth order log-domain multifunction filter (MFF, which can yield four possible stable filter configurations, each offering simultaneously lowpass (LP, highpass (HP, and bandpass (BP frequency responses, is presented. The features of these filters are very simple, consisting of merely a few exponential transconductor cells and capacitors; all grounded elements, capable of absorbing the shunt parasitic capacitances, responses are electronically tuneable, and suitable for monolithic integration. Furthermore, being designed using log-domain technique, it offers all its advantages. As an example, 5th-order MFFs are designed in each case and their performances are evaluated through simulation. Lastly, a comparative study of the MFFs is also carried, which helps in selecting better high-order MFF for a given application.

  9. A review of current concepts in flexor tendon repair: physiology, biomechanics, surgical technique and rehabilitation.

    Directory of Open Access Journals (Sweden)

    Rohit Singh

    2015-12-01

    Full Text Available Historically, the surgical treatment of flexor tendon injuries has always been associated with controversy. It was not until 1967, when the paper entitled Primary repair of flexor tendons in no man’s land was presented at the American Society of Hand Surgery, which reported excellent results and catalyzed the implementation of this technique into world-wide practice. We present an up to date literature review using PubMed and Google Scholar where the terms flexor tendon, repair and rehabilitation were used. Topics covered included functional anatomy, nutrition, biomechanics, suture repair, repair site gapping, and rehabilitation. This article aims to provide a comprehensive and complete overview of flexor tendon repairs.

  10. Direct imaging of neural currents using ultra-low field magnetic resonance techniques

    Science.gov (United States)

    Volegov, Petr L.; Matlashov, Andrei N.; Mosher, John C.; Espy, Michelle A.; Kraus, Jr., Robert H.

    2009-08-11

    Using resonant interactions to directly and tomographically image neural activity in the human brain using magnetic resonance imaging (MRI) techniques at ultra-low field (ULF), the present inventors have established an approach that is sensitive to magnetic field distributions local to the spin population in cortex at the Larmor frequency of the measurement field. Because the Larmor frequency can be readily manipulated (through varying B.sub.m), one can also envision using ULF-DNI to image the frequency distribution of the local fields in cortex. Such information, taken together with simultaneous acquisition of MEG and ULF-NMR signals, enables non-invasive exploration of the correlation between local fields induced by neural activity in cortex and more `distant` measures of brain activity such as MEG and EEG.

  11. Unmanned air/ground vehicles heterogeneous cooperative techniques:Current status and prospects

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Multiple unmanned air/ground vehicles heterogeneous cooperation is a novel and challenging filed.Heterogeneous cooperative techniques can widen the application fields of unmanned air or ground vehicles,and enhance the effectiveness of implementing detection,search and rescue tasks.This paper mainly focused on the key issues in multiple unmanned air/ground vehicles heterogeneous cooperation,including heterogeneous flocking,formation control,formation stability,network control,and actual applications.The main problems and future directions in this field were also analyzed in detail.These innovative technologies can significantly enhance the effectiveness of implementing complicated tasks,which definitely provide a series of novel breakthroughs for the intelligence,integration and advancement of future robot systems.

  12. Prospective memory rehabilitation based on visual imagery techniques.

    Science.gov (United States)

    Potvin, Marie-Julie; Rouleau, Isabelle; Sénéchal, Geneviève; Giguère, Jean-François

    2011-12-01

    Despite the frequency of prospective memory (PM) problems in the traumatic brain injury (TBI) population, there are only a few rehabilitation programmes that have been specifically designed to address this issue, other than those using external compensatory strategies. In the present study, a PM rehabilitation programme based on visual imagery techniques expected to strengthen the cue-action association was developed. Ten moderate to severe chronic TBI patients learned to create a mental image representing the association between a prospective cue and an intended action within progressively more complex and naturalistic PM tasks. We hypothesised that compared to TBI patients (n = 20) who received a short session of education (control condition), TBI patients in the rehabilitation group would exhibit a greater improvement on the event-based than on the time-based condition of a PM ecological task. Results revealed however that this programme was similarly beneficial for both conditions. TBI patients in the rehabilitation group and their relatives also reported less everyday PM failures following the programme, which suggests generalisation. The PM improvement appears to be specific since results on cognitive control tasks remained similar. Therefore, visual imagery techniques appear to improve PM functioning by strengthening the memory trace of the intentions and inducing an automatic recall of the intentions.

  13. Antimisting kerosene: Base fuel effects, blending and quality control techniques

    Science.gov (United States)

    Yavrouian, A. H.; Ernest, J.; Sarohia, V.

    1984-01-01

    The problems associated with blending of the AMK additive with Jet A, and the base fuel effects on AMK properties are addressed. The results from the evaluation of some of the quality control techniques for AMK are presented. The principal conclusions of this investigation are: significant compositional differences for base fuel (Jet A) within the ASTM specification DI655; higher aromatic content of the base fuel was found to be beneficial for the polymer dissolution at ambient (20 C) temperature; using static mixer technology, the antimisting additive (FM-9) is in-line blended with Jet A, producing AMK which has adequate fire-protection properties 15 to 20 minutes after blending; degradability of freshly blended and equilibrated AMK indicated that maximum degradability is reached after adequate fire protection is obtained; the results of AMK degradability as measured by filter ratio, confirmed previous RAE data that power requirements to decade freshly blended AMK are significantly higher than equilibrated AMK; blending of the additive by using FM-9 concentrate in Jet A produces equilibrated AMK almost instantly; nephelometry offers a simple continuous monitoring capability and is used as a real time quality control device for AMK; and trajectory (jet thurst) and pressure drop tests are useful laboratory techniques for evaluating AMK quality.

  14. Current advances and future perspectives in extrusion-based bioprinting.

    Science.gov (United States)

    Ozbolat, Ibrahim T; Hospodiuk, Monika

    2016-01-01

    Extrusion-based bioprinting (EBB) is a rapidly growing technology that has made substantial progress during the last decade. It has great versatility in printing various biologics, including cells, tissues, tissue constructs, organ modules and microfluidic devices, in applications from basic research and pharmaceutics to clinics. Despite the great benefits and flexibility in printing a wide range of bioinks, including tissue spheroids, tissue strands, cell pellets, decellularized matrix components, micro-carriers and cell-laden hydrogels, the technology currently faces several limitations and challenges. These include impediments to organ fabrication, the limited resolution of printed features, the need for advanced bioprinting solutions to transition the technology bench to bedside, the necessity of new bioink development for rapid, safe and sustainable delivery of cells in a biomimetically organized microenvironment, and regulatory concerns to transform the technology into a product. This paper, presenting a first-time comprehensive review of EBB, discusses the current advancements in EBB technology and highlights future directions to transform the technology to generate viable end products for tissue engineering and regenerative medicine.

  15. Fuzzy Controller based Neutral Current Harmonic Suppression in Distribution System

    Directory of Open Access Journals (Sweden)

    T.Guna Sekar

    2013-10-01

    Full Text Available Recent surveys of three-phase four-wire electric systems, buildings and industrial plants with computers and non-linear loads shows the excessive currents in the neutral conductor. This is mainly due to unbalancing system and non-linear loads. Third order harmonics are much dominant in the neutral conductor due to the presence of zero sequence components. In response to this concern, this paper presents a concept of series active filter scheme to suppress the neutral current harmonics to reduce the burden of the secondary of the distribution transformer. In this scheme, the series active filteris connected in series with the neutral conductor to eliminate the zero sequence components in the neutral conductor. In this paper, Fuzzy based controller is used to extract the harmonic component in the neutral conductor. The proposed method improves the overall performance of the system and eliminates the burden of the neutral conductor. To validate the proposed simulation results, a scale-down prototype experimental model is developed.

  16. Current Source Converter Based Wind Energy Conversion Systems

    Institute of Scientific and Technical Information of China (English)

    Samir Kouro; Jing-ya DAI; Bin WU

    2011-01-01

    The increase in the installed capacity of wind energy conversion systems (WECS) has triggered the development of more demanding grid codes and additional requirements on performance.In order to meet these requirements the industry trend has shifted to full-scale power converter interfaces in modern multi-megawatt WECS.As consequence,a wide variety of new power converter topologies and WECS configurations have been introduced in recent years.Among them,current source converter(CSC) based configurations have attracted attention due to a series of advantages like:simple structure,grid friendly waveforms,controllable power factor,and reliable grid short-circuit protection.This paper presents the latest developments in CSC interfaces for WECS and related technologies such as modulation methods,control schemes and grid code compatibility.

  17. Fault diagnosis of motor drives using stator current signal analysis based on dynamic time warping

    Science.gov (United States)

    Zhen, D.; Wang, T.; Gu, F.; Ball, A. D.

    2013-01-01

    Electrical motor stator current signals have been widely used to monitor the condition of induction machines and their downstream mechanical equipment. The key technique used for current signal analysis is based on Fourier transform (FT) to extract weak fault sideband components from signals predominated with supply frequency component and its higher order harmonics. However, the FT based method has limitations such as spectral leakage and aliasing, leading to significant errors in estimating the sideband components. Therefore, this paper presents the use of dynamic time warping (DTW) to process the motor current signals for detecting and quantifying common faults in a downstream two-stage reciprocating compressor. DTW is a time domain based method and its algorithm is simple and easy to be embedded into real-time devices. In this study DTW is used to suppress the supply frequency component and highlight the sideband components based on the introduction of a reference signal which has the same frequency component as that of the supply power. Moreover, a sliding window is designed to process the raw signal using DTW frame by frame for effective calculation. Based on the proposed method, the stator current signals measured from the compressor induced with different common faults and under different loads are analysed for fault diagnosis. Results show that DTW based on residual signal analysis through the introduction of a reference signal allows the supply components to be suppressed well so that the fault related sideband components are highlighted for obtaining accurate fault detection and diagnosis results. In particular, the root mean square (RMS) values of the residual signal can indicate the differences between the healthy case and different faults under varying discharge pressures. It provides an effective and easy approach to the analysis of motor current signals for better fault diagnosis of the downstream mechanical equipment of motor drives in the time

  18. A novel fast full inversion based breast ultrasound elastography technique.

    Science.gov (United States)

    Karimi, Hirad; Fenster, Aaron; Samani, Abbas

    2013-04-07

    Cancer detection and classification have been the focus of many imaging and therapeutic research studies. Elastography is a non-invasive technique to visualize suspicious soft tissue areas where tissue stiffness is used as image contrast mechanism. In this study, a breast ultrasound elastography system including software and hardware is proposed. Unlike current elastography systems that image the tissue strain and present it as an approximation to relative tissue stiffness, this system is capable of imaging the breast absolute Young's modulus in fast fashion. To improve the quality of elastography images, a novel system consisting of two load cells has been attached to the ultrasound probe. The load cells measure the breast surface forces to be used for calculating the tissue stress distribution throughout the breast. To facilitate fast imaging, this stress calculation is conducted by an accelerated finite element method. Acquired tissue displacements and surface force data are used as input to the proposed Young's modulus reconstruction technique. Numerical and tissue mimicking phantom studies were conducted for validating the proposed system. These studies indicated that fast imaging of breast tissue absolute Young's modulus using the proposed ultrasound elastography system is feasible. The tissue mimicking phantom study indicated that the system is capable of providing reliable absolute Young's modulus values for both normal tissue and tumour as the maximum Young's modulus reconstruction error was less than 6%. This demonstrates that the proposed system has a good potential to be used for clinical breast cancer assessment.

  19. A novel fast full inversion based breast ultrasound elastography technique

    Science.gov (United States)

    Karimi, Hirad; Fenster, Aaron; Samani, Abbas

    2013-04-01

    Cancer detection and classification have been the focus of many imaging and therapeutic research studies. Elastography is a non-invasive technique to visualize suspicious soft tissue areas where tissue stiffness is used as image contrast mechanism. In this study, a breast ultrasound elastography system including software and hardware is proposed. Unlike current elastography systems that image the tissue strain and present it as an approximation to relative tissue stiffness, this system is capable of imaging the breast absolute Young’s modulus in fast fashion. To improve the quality of elastography images, a novel system consisting of two load cells has been attached to the ultrasound probe. The load cells measure the breast surface forces to be used for calculating the tissue stress distribution throughout the breast. To facilitate fast imaging, this stress calculation is conducted by an accelerated finite element method. Acquired tissue displacements and surface force data are used as input to the proposed Young’s modulus reconstruction technique. Numerical and tissue mimicking phantom studies were conducted for validating the proposed system. These studies indicated that fast imaging of breast tissue absolute Young’s modulus using the proposed ultrasound elastography system is feasible. The tissue mimicking phantom study indicated that the system is capable of providing reliable absolute Young’s modulus values for both normal tissue and tumour as the maximum Young’s modulus reconstruction error was less than 6%. This demonstrates that the proposed system has a good potential to be used for clinical breast cancer assessment.

  20. Transformer-based design techniques for oscillators and frequency dividers

    CERN Document Server

    Luong, Howard Cam

    2016-01-01

    This book provides in-depth coverage of transformer-based design techniques that enable CMOS oscillators and frequency dividers to achieve state-of-the-art performance.  Design, optimization, and measured performance of oscillators and frequency dividers for different applications are discussed in detail, focusing on not only ultra-low supply voltage but also ultra-wide frequency tuning range and locking range.  This book will be an invaluable reference for anyone working or interested in CMOS radio-frequency or mm-Wave integrated circuits and systems.

  1. Modal Analysis Based on the Random Decrement Technique

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune

    1998-01-01

    This article describes the work carried out within the project: Modal Analysis Based on the Random Decrement Technique - Application to Civil Engineering Structures. The project is part of the research programme: Dynamics of Structures sponsored by the Danish Technical Research Counsil. The planned...... contents and the requirement for the project prior to its start are described together with thee results obtained during the 3 year period of the project. The project was mainly carried out as a Ph.D project by the first author from September 1994 to August 1997 in cooperation with associate professor Rune...

  2. Office-based tracheoesophageal puncture: updates in techniques and outcomes.

    Science.gov (United States)

    Bergeron, Jennifer L; Jamal, Nausheen; Erman, Andrew; Chhetri, Dinesh K

    2014-01-01

    Tracheoesophageal puncture (TEP) is an effective rehabilitation method for postlaryngectomy speech and has already been described as a procedure that is safely performed in the office. We review our long-term experience with office-based TEP over the past 7 years in the largest cohort published to date. A retrospective chart review was performed of all patients who underwent TEP by a single surgeon from 2005 through 2012, including office-based and operating room procedures. Indications for the chosen technique (office versus operating room) and surgical outcomes were evaluated. Fifty-nine patients underwent 72 TEP procedures, with 55 performed in the outpatient setting and 17 performed in the operating room, all without complication. The indications for performing TEPs in the operating room included 2 primary TEPs, 14 due to concomitant procedures requiring general anesthesia, and 1 due to failed attempt at office-based TEP. Nineteen patients with prior rotational or free flap reconstruction successfully underwent office-based TEP. TEP in an office-based setting with immediate voice prosthesis placement continues to be a safe method of voice rehabilitation for postlaryngectomy patients, including those who have previously undergone free flap or rotational flap reconstruction. Office-based TEP is now our primary approach for postlaryngectomy voice rehabilitation. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. What's down below? Current and potential future applications of geophysical techniques to identify subsurface permafrost conditions (Invited)

    Science.gov (United States)

    Douglas, T. A.; Bjella, K.; Campbell, S. W.

    2013-12-01

    For infrastructure design, operations, and maintenance requirements in the North the ability to accurately and efficiently detect the presence (or absence) of ground ice in permafrost terrains is a serious challenge. Ground ice features including ice wedges, thermokarst cave-ice, and segregation ice are present in a variety of spatial scales and patterns. Currently, most engineering applications use borehole logging and sampling to extrapolate conditions at the point scale. However, there is high risk of over or under estimating the presence of frozen or unfrozen features when relying on borehole information alone. In addition, boreholes are costly, especially for planning linear structures like roads or runways. Predicted climate warming will provide further challenges for infrastructure development and transportation operations where permafrost degradation occurs. Accurately identifying the subsurface character in permafrost terrains will allow engineers and planners to cost effectively create novel infrastructure designs to withstand the changing environment. There is thus a great need for a low cost rapidly deployable, spatially extensive means of 'measuring' subsurface conditions. Geophysical measurements, both terrestrial and airborne, have strong potential to revolutionize our way of mapping subsurface conditions. Many studies in continuous and discontinuous permafrost have used geophysical measurements to identify discrete features and repeatable patterns in the subsurface. The most common measurements include galvanic and capacitive coupled resistivity, ground penetrating radar, and multi frequency electromagnetic induction techniques. Each of these measurements has strengths, weaknesses, and limitations. By combining horizontal geophysical measurements, downhole geophysics, multispectral remote sensing images, LiDAR measurements, and soil and vegetation mapping we can start to assemble a holistic view of how surface conditions and standoff measurements

  4. The use of guided tissue regeneration techniques among endodontists: a web-based survey.

    Science.gov (United States)

    Naylor, Justin; Mines, Pete; Anderson, Alfred; Kwon, David

    2011-11-01

    The purpose of this study was to determine factors and clinical situations that influence an endodontist's decision to use guided tissue regeneration (GTR) techniques during endodontic root-end surgery. An invitation to participate in a web-based survey was e-mailed to 3,750 members of the American Association of Endodontists. Data were collected from 1,129 participants, representing a 30.1% completion rate. The number of questions varied from 3 to 11 depending on individual responses. 40.7% of respondents who perform root-end surgeries also use GTR techniques. The clinical situation in which GTR techniques are used most often is for transosseous lesions. Barrier membranes and bone replacement grafts are each used by more than 85% of respondents using GTR techniques. Insufficient training and insufficient evidence in support of its use were selected as the predominant reasons for not using GTR techniques at 42.4% and 32%, respectively. Although over 40% of respondents are currently using GTR techniques in conjunction with their root-end surgeries, a majority of those who do not use GTR indicated they would consider using these techniques with better evidence and available training. Published by Elsevier Inc.

  5. The current state of intestine transplantation: indications, techniques, outcomes and challenges.

    Science.gov (United States)

    Sudan, D

    2014-09-01

    Intestine transplantation is the least common form of organ transplantation in the United States and often deemed one of the most difficult. Patient and graft survival have historically trailed well behind other organ transplants. Over the past 5-10 years registry reports and single center series have demonstrated improvements to patient survival after intestinal transplantation that now match patient survival for those without life-threatening complications on parenteral nutrition. For various reasons including improvements in medical care of patients with intestinal failure and difficulty accessing transplant care, the actual number of intestine transplants has declined by 25% over the past 6 years. In light of the small numbers of intestine transplants, many physicians and the lay public are often unaware that this is a therapeutic option. The aim of this review is to describe the current indications, outcomes and advances in the field of intestine transplantation and to explore concerns over future access to this important and life-saving therapy.

  6. In vivo and in vitro starch digestion: are current in vitro techniques adequate?

    Science.gov (United States)

    Hasjim, Jovin; Lavau, Gautier Cesbron; Gidley, Michael J; Gilbert, Robert G

    2010-12-13

    The time evolution of the size distributions of (fully branched and debranched) starch molecules during in vivo and in vitro digestion was analyzed using size exclusion chromatography (SEC) and compared. In vivo digesta were collected from the small intestine of pigs fed with raw normal maize starch; in vitro digestion was carried out on the same diet fed to the pigs using a method simulating digestion in the mouth, stomach, and small intestine. A qualitative difference was observed between the in vitro and the in vivo digestion. The former showed a degradation of starch molecules to a more uniform size, whereas the in vivo digestion preserved the size distribution of native starch before producing a multimodal distribution, the heterogeneous nature of which current in vitro methods do not reproduce. The use of in vitro digestion to infer in vivo digestion patterns and, hence, potential nutrition benefits need to take account of this phenomenon.

  7. Acute gastrointestinal bleeding: emerging role of multidetector CT angiography and review of current imaging techniques.

    Science.gov (United States)

    Laing, Christopher J; Tobias, Terrence; Rosenblum, David I; Banker, Wade L; Tseng, Lee; Tamarkin, Stephen W

    2007-01-01

    Acute gastrointestinal bleeding is a common cause of hospitalization, morbidity, and mortality in the United States. The evaluation and treatment of acute gastrointestinal bleeding are complex and often require a multispecialty approach involving gastroenterologists, surgeons, internists, emergency physicians, and radiologists. The multitude of pathologic processes that can result in gastrointestinal bleeding, the length of the gastrointestinal tract, and the often intermittent nature of gastrointestinal bleeding further complicate patient evaluation. In addition, there are multiple imaging modalities and therapeutic interventions that are currently being used in the evaluation and treatment of acute gastrointestinal hemorrhage, each with its own strengths and weaknesses. Initial experience indicates that multidetector computed tomographic angiography is a promising first-line modality for the time-efficient, sensitive, and accurate diagnosis or exclusion of active gastrointestinal hemorrhage and may have a profound impact on the evaluation and subsequent treatment of patients who present with acute gastrointestinal bleeding.

  8. Structural level characterization of base oils using advanced analytical techniques

    KAUST Repository

    Hourani, Nadim

    2015-05-21

    Base oils, blended for finished lubricant formulations, are classified by the American Petroleum Institute into five groups, viz., groups I-V. Groups I-III consist of petroleum based hydrocarbons whereas groups IV and V are made of synthetic polymers. In the present study, five base oil samples belonging to groups I and III were extensively characterized using high performance liquid chromatography (HPLC), comprehensive two-dimensional gas chromatography (GC×GC), and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) equipped with atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) sources. First, the capabilities and limitations of each analytical technique were evaluated, and then the availed information was combined to reveal compositional details on the base oil samples studied. HPLC showed the overwhelming presence of saturated over aromatic compounds in all five base oils. A similar trend was further corroborated using GC×GC, which yielded semiquantitative information on the compound classes present in the samples and provided further details on the carbon number distributions within these classes. In addition to chromatography methods, FT-ICR MS supplemented the compositional information on the base oil samples by resolving the aromatics compounds into alkyl- and naphtheno-subtituted families. APCI proved more effective for the ionization of the highly saturated base oil components compared to APPI. Furthermore, for the detailed information on hydrocarbon molecules FT-ICR MS revealed the presence of saturated and aromatic sulfur species in all base oil samples. The results presented herein offer a unique perspective into the detailed molecular structure of base oils typically used to formulate lubricants. © 2015 American Chemical Society.

  9. A Comparative Analysis of Exemplar Based and Wavelet Based Inpainting Technique

    Directory of Open Access Journals (Sweden)

    Vaibhav V Nalawade

    2012-06-01

    Full Text Available Image inpainting is the process of filling in of missing region so as to preserve its overall continuity. Image inpainting is manipulation and modification of an image in a form that is not easily detected. Digital image inpainting is relatively new area of research, but numerous and different approaches to tackle the inpainting problem have been proposed since the concept was first introduced. This paper compares two separate techniques viz, Exemplar based inpainting technique and Wavelet based inpainting technique, each portraying a different set of characteristics. The algorithms analyzed under exemplar technique are large object removal by exemplar based inpainting technique (Criminisi’s and modified exemplar (Cheng. The algorithm analyzed under wavelet is Chen’s visual image inpainting method. A number of examples on real and synthetic images are demonstrated to compare the results of different algorithms using both qualitative and quantitative parameters.

  10. Hysteresis current control technique of VSI for compensation of grid-connected unbalanced loads

    DEFF Research Database (Denmark)

    Pouresmaeil, Edris; Akorede, Mudathir Funsho; Montesinos-Miracle, Daniel

    2014-01-01

    The global trends nowadays in the power generation industry are to supplement the electricity production using distributed generation (DG) technologies based on renewable energy resources such as photovoltaic, wind power, etc. However, failure to properly control the operation of distributed energy...

  11. 3D cell culture: a review of current approaches and techniques.

    Science.gov (United States)

    Haycock, John W

    2011-01-01

    Cell culture in two dimensions has been routinely and diligently undertaken in thousands of laboratories worldwide for the past four decades. However, the culture of cells in two dimensions is arguably primitive and does not reproduce the anatomy or physiology of a tissue for informative or useful study. Creating a third dimension for cell culture is clearly more relevant, but requires a multidisciplinary approach and multidisciplinary expertise. When entering the third dimension, investigators need to consider the design of scaffolds for supporting the organisation of cells or the use of bioreactors for controlling nutrient and waste product exchange. As 3D culture systems become more mature and relevant to human and animal physiology, the ability to design and develop co-cultures becomes possible as does the ability to integrate stem cells. The primary objectives for developing 3D cell culture systems vary widely - and range from engineering tissues for clinical delivery through to the development of models for drug screening. The intention of this review is to provide a general overview of the common approaches and techniques for designing 3D culture models.

  12. A crossbar resistance switching memory readout scheme with sneak current cancellation based on a two-port current-mode sensing.

    Science.gov (United States)

    Bae, Woorham; Yoon, Kyung Jean; Hwang, Cheol Seong; Jeong, Deog-Kyoon

    2016-12-02

    This paper describes a novel readout scheme that enables the complete cancellation of sneak currents in resistive switching random-access memory (RRAM) crossbar array. The current-mode readout is employed in the proposed readout, and a few critical advantages of the current-mode readout for crossbar RRAM are elucidated in this paper. The proposed scheme is based on a floating readout scheme for low power consumption, and one more sensing port is introduced using an additional reference word line. From the additional port, information on the sneak current amount is collected, and simple current-mode arithmetic operations are implemented to cancel out the sneak current from the sensing current. In addition, a simple method of handling the overestimated-sneak-current issue is described. The proposed scheme is verified using HSPICE simulation. Moreover, an example of a current-mode sense amplifier realizing the proposed cancelling technique is presented. The proposed sense amplifier can be implemented with less hardware overhead compared to the previous works.

  13. A crossbar resistance switching memory readout scheme with sneak current cancellation based on a two-port current-mode sensing

    Science.gov (United States)

    Bae, Woorham; Yoon, Kyung Jean; Hwang, Cheol Seong; Jeong, Deog-Kyoon

    2016-12-01

    This paper describes a novel readout scheme that enables the complete cancellation of sneak currents in resistive switching random-access memory (RRAM) crossbar array. The current-mode readout is employed in the proposed readout, and a few critical advantages of the current-mode readout for crossbar RRAM are elucidated in this paper. The proposed scheme is based on a floating readout scheme for low power consumption, and one more sensing port is introduced using an additional reference word line. From the additional port, information on the sneak current amount is collected, and simple current-mode arithmetic operations are implemented to cancel out the sneak current from the sensing current. In addition, a simple method of handling the overestimated-sneak-current issue is described. The proposed scheme is verified using HSPICE simulation. Moreover, an example of a current-mode sense amplifier realizing the proposed cancelling technique is presented. The proposed sense amplifier can be implemented with less hardware overhead compared to the previous works.

  14. Biosensor-based microRNA detection: techniques, design, performance, and challenges.

    Science.gov (United States)

    Johnson, Blake N; Mutharasan, Raj

    2014-04-07

    The current state of biosensor-based techniques for amplification-free microRNA (miRNA) detection is critically reviewed. Comparison with non-sensor and amplification-based molecular techniques (MTs), such as polymerase-based methods, is made in terms of transduction mechanism, associated protocol, and sensitivity. Challenges associated with miRNA hybridization thermodynamics which affect assay selectivity and amplification bias are briefly discussed. Electrochemical, electromechanical, and optical classes of miRNA biosensors are reviewed in terms of transduction mechanism, limit of detection (LOD), time-to-results (TTR), multiplexing potential, and measurement robustness. Current trends suggest that biosensor-based techniques (BTs) for miRNA assay will complement MTs due to the advantages of amplification-free detection, LOD being femtomolar (fM)-attomolar (aM), short TTR, multiplexing capability, and minimal sample preparation requirement. Areas of future importance in miRNA BT development are presented which include focus on achieving high measurement confidence and multiplexing capabilities.

  15. ONLINE GRINDING WHEEL WEAR COMPENSATION BY IMAGE BASED MEASURING TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    WAN Daping; HU Dejin; WU Qi; ZHANG Yonghong

    2006-01-01

    Automatic compensation of grinding wheel wear in dry grinding is accomplished by an image based online measurement method. A kind of PC-based charge-coupled device image recognition system is schemed out, which detects the topography changes of the grinding wheel surface. Profile data, which corresponds to the wear and the topography, is measured by using a digital image processing method. The grinding wheel wear is evaluated by analyzing the position deviation of the grinding wheel edge. The online wear compensation is achieved according to the measure results. The precise detection and automatic compensation system is integrated into an open structure CNC curve grinding machine. A practical application is carried out to fulfil the precision curve grinding. The experimental results confirm the benefits of the proposed techniques, and the online detection accuracy is less than 5 μm. The grinding machine provides higher precision according to the in-process grinding wheel error compensation.

  16. On combining Laplacian and optimization-based mesh smoothing techniques

    Energy Technology Data Exchange (ETDEWEB)

    Freitag, L.A.

    1997-07-01

    Local mesh smoothing algorithms have been shown to be effective in repairing distorted elements in automatically generated meshes. The simplest such algorithm is Laplacian smoothing, which moves grid points to the geometric center of incident vertices. Unfortunately, this method operates heuristically and can create invalid meshes or elements of worse quality than those contained in the original mesh. In contrast, optimization-based methods are designed to maximize some measure of mesh quality and are very effective at eliminating extremal angles in the mesh. These improvements come at a higher computational cost, however. In this article the author proposes three smoothing techniques that combine a smart variant of Laplacian smoothing with an optimization-based approach. Several numerical experiments are performed that compare the mesh quality and computational cost for each of the methods in two and three dimensions. The author finds that the combined approaches are very cost effective and yield high-quality meshes.

  17. Hash Based Least Significant Bit Technique For Video Steganography

    Directory of Open Access Journals (Sweden)

    Prof. Dr. P. R. Deshmukh ,

    2014-01-01

    Full Text Available The Hash Based Least Significant Bit Technique For Video Steganography deals with hiding secret message or information within a video.Steganography is nothing but the covered writing it includes process that conceals information within other data and also conceals the fact that a secret message is being sent.Steganography is the art of secret communication or the science of invisible communication. In this paper a Hash based least significant bit technique for video steganography has been proposed whose main goal is to embed a secret information in a particular video file and then extract it using a stego key or password. In this Least Significant Bit insertion method is used for steganography so as to embed data in cover video with change in the lower bit.This LSB insertion is not visible.Data hidding is the process of embedding information in a video without changing its perceptual quality. The proposed method involve with two terms that are Peak Signal to Noise Ratio (PSNR and the Mean Square Error (MSE .This two terms measured between the original video files and steganographic video files from all video frames where a distortion is measured using PSNR. A hash function is used to select the particular position for insertion of bits of secret message in LSB bits.

  18. Current pathology work-up of extremity soft tissue sarcomas, evaluation of the validity of different techniques

    NARCIS (Netherlands)

    Verheijen, P.; Witjes, H.; van Gorp, J.; Hennipman, A.; van Dalen, T.

    2010-01-01

    Objective: In patients with extremity soft tissue sarcomas (STSs) a correct histopathological diagnosis is considered important before surgical treatment. We evaluated the preoperative use and sensitivity of the various pathology techniques. Methods: In a population-based study in patients operated

  19. Re: Current Standard Technique for Modern Flexible Ureteroscopy: Tips and Tricks

    Directory of Open Access Journals (Sweden)

    Selçuk Keskin

    2016-09-01

    Full Text Available The prevalence of urinary stone disease is increasing worldwide. The dissemination of the clinical use of ultrasound has improved the diagnosis of stones at an earlier stage. It has increased the expansion of the indications of flexible ureterorenoscopy (fURS. With the advances in flexible ureteroscopy (FU, more successful outcomes are being reported. The most recent EAU guidelines state that for all stones smaller than 2 cm, fURS can be the first choice of treatment. Especially for lower pole stones, the stone free rate is better than that with extracorporeal shock wave lithotripsy. For stones larger than 2 cm staged procedures may be necessary. This paper recommends a standardized technique for fURS to decrease the rate of possible complications, and increase the success rate. Endourological techniques are widely adopted by most of the urological surgeons, hence fURS is an expansion of our surgical armamentarium. In this paper, an experienced group recommends some tips and tricks for each step of the procedure. The authors recommend general anesthesia over spinal anesthesia for two reasons: larger tidal volume during spinal anesthesia may cause movement, which can make the procedure harder. Secondly, the duration of the spinal anesthesia may be too short for some cases. The placement of ureteral access sheath (UAS should be done under fluoroscopic guidance and proper force should be applied. Ideally, the distal tip of the UAS should be just below the ureteropelvic junction. For preventing functional deterioration of the FU, the tip of the laser probe should be out of the scope as far as one-quarter of the screen diameter. For preventing excessive prolonged deflections, the stones in the lower pole should be repositioned in order to allow a more straight working channel. Pulverization of the stone is preferred over fragmentation since it decreases the operation time and risk of injury during removal of fragments. A power setting of low

  20. Re: Current Standard Technique for Modern Flexible Ureteroscopy: Tips and Tricks

    Directory of Open Access Journals (Sweden)

    Emre Selçuk Keskin

    2016-12-01

    Full Text Available EDITORIAL COMMENT The prevalence of urinary stone disease is increasing worldwide. The dissemination of the clinical use of the ultrasound has increased the rate of diagnosis of stones at an earlier stage, thus, has increased the expansion of the indications for flexible ureterorenoscopy (fURS. With the advancements in flexible ureteroscopy (FU, more successful outcomes are being reported. The most recent EAU guidelines state that fURS can be the first choice of treatment for all stones smaller than 2 cm. Especially for the lower pole stones, the stone-free rate is better than that with extracorporeal shock wave lithotripsy. For stones larger than 2 cm, staged procedures may be necessary. This paper recommends a standardized technique for fURS which is aimed to decrease the rate of possible complications and increase the success rate. Endourological techniques are widely adopted by most of the urological surgeons, hence fURS is an expansion of our surgical armamentarium. In this paper, an experienced group recommended some tips and tricks for each step of the procedure. The authors recommended general anesthesia over spinal anesthesia for two reasons: larger tidal volume during spinal anesthesia may cause movement, which can make the procedure harder. Secondly, the duration of the spinal anesthesia may be too short for some cases. Placement of ureteral access sheath (UAS should be done under fluoroscopic guidance and proper force should be applied. Ideally, the distal tip of the UAS should be just below the ureteropelvic junction. For preventing functional deterioration of the FU, the tip of the laser probe should be out of the scope as far as one-quarter of the screen diameter. For preventing excessive prolonged deflections, the stones in the lower pole should be repositioned in order to allow a more straight working channel. Pulverization of the stone is preferred over fragmentation since it decreases the operative time and risk of injury

  1. Techniques used for the screening of hemoglobin levels in blood donors: current insights and future directions

    Directory of Open Access Journals (Sweden)

    Chaudhary R

    2017-07-01

    Full Text Available Rajendra Chaudhary,1 Anju Dubey,2 Atul Sonker3 1Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, 2Department of Transfusion Medicine, T.S. Misra Medical College and Hospital, 3Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India Abstract: Blood donor hemoglobin (Hb estimation is an important donation test that is performed prior to blood donation. It serves the dual purpose of protecting the donors’ health against anemia and ensuring good quality of blood components, which has an implication on recipients’ health. Diverse cutoff criteria have been defined world over depending on population characteristics; however, no testing methodology and sample requirement have been specified for Hb screening. Besides the technique, there are several physiological and methodological factors that affect accuracy and reliability of Hb estimation. These include the anatomical source of blood sample, posture of the donor, timing of sample and several other biological factors. Qualitative copper sulfate gravimetric method has been the archaic time-tested method that is still used in resource-constrained settings. Portable hemoglobinometers are modern quantitative devices that have been further modified to reagent-free cuvettes. Furthermore, noninvasive spectrophotometry was introduced, mitigating pain to blood donor and eliminating risk of infection. Notwithstanding a tremendous evolution in terms of ease of operation, accuracy, mobility, rapidity and cost, a component of inherent variability persists, which may partly be attributed to pre-analytical variables. Hence, blood centers should pay due attention to validation of test methodology, competency of operating staff and regular proficiency testing of the outputs. In this article, we have reviewed various regulatory guidelines, described the variables that affect the measurements and compared the validated

  2. Comparison of advanced optical imaging techniques with current otolaryngology diagnostics for improved middle ear assessment (Conference Presentation)

    Science.gov (United States)

    Nolan, Ryan M.; Shelton, Ryan L.; Monroy, Guillermo L.; Spillman, Darold R.; Novak, Michael A.; Boppart, Stephen A.

    2016-02-01

    Otolaryngologists utilize a variety of diagnostic techniques to assess middle ear health. Tympanometry, audiometry, and otoacoustic emissions examine the mobility of the tympanic membrane (eardrum) and ossicles using ear canal pressure and auditory tone delivery and detection. Laser Doppler vibrometry provides non-contact vibrational measurement, and acoustic reflectometry is used to assess middle ear effusion using sonar. These technologies and techniques have advanced the field beyond the use of the standard otoscope, a simple tissue magnifier, yet the need for direct visualization of middle ear disease for superior detection, assessment, and management remains. In this study, we evaluated the use of portable optical coherence tomography (OCT) and pneumatic low-coherence interferometry (LCI) systems with handheld probe delivery to standard tympanometry, audiometry, otoacoustic emissions, laser Doppler vibrometry, and acoustic reflectometry. Comparison of these advanced optical imaging techniques and current diagnostics was conducted with a case study subject with a history of unilateral eardrum trauma. OCT and pneumatic LCI provide novel dynamic spatiotemporal structural data of the middle ear, such as the thickness of the eardrum and quantitative detection of underlying disease pathology, which could allow for more accurate diagnosis and more appropriate management than currently possible.

  3. Analysis and Minimization of Output Current Ripple for Discontinuous Pulse-Width Modulation Techniques in Three-Phase Inverters

    Directory of Open Access Journals (Sweden)

    Gabriele Grandi

    2016-05-01

    Full Text Available This paper gives the complete analysis of the output current ripple in three-phase voltage source inverters considering the different discontinuous pulse-width modulation (DPWM strategies. In particular, peak-to-peak current ripple amplitude is analytically evaluated over the fundamental period and compared among the most used DPWMs, including positive and negative clamped (DPWM+ and DPWM−, and the four possible combinations between them, usually named as DPWM0, DPWM1, DPWM2, and DPWM3. The maximum and the average values of peak-to-peak current ripple are estimated, and a simple method to correlate the ripple envelope with the ripple rms is proposed and verified. Furthermore, all the results obtained by DPWMs are compared to the centered pulse-width modulation (CPWM, equivalent to the space vector modulation to identify the optimal pulse-width modulation (PWM strategy as a function of the modulation index, taking into account the different average switching frequency. In this way, the PWM technique providing for the minimum output current ripple is identified over the whole modulation range. The analytical developments and the main results are experimentally verified by current ripple measurements with a three-phase PWM inverter prototype supplying an induction motor load.

  4. Robust low frequency current ripple elimination algorithm for grid-connected fuel cell systems with power balancing technique

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Soo; Choe, Gyu-Yeong; Lee, Byoung-Kuk [School of Information and Communication Engineering, Sungkyunkwan University, 300 Cheoncheon-dong, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Kang, Hyun-Soo [R and D Center, Advanced Drive Technology (ADT) Company, 689-26 Geumjeong-dong, Gunpo-si, Gyeonggi-do 435-862 (Korea, Republic of)

    2011-05-15

    The low frequency current ripple in grid-connected fuel cell systems is generated from dc-ac inverter operation, which generates 60 Hz fundamental component, and gives harmful effects on fuel cell stack itself, such as making cathode surface responses slower, causing an increase of more than 10% in the fuel consumption, creating oxygen starvation, causing a reduction in the operating lifetime, and incurring a nuisance tripping such as overload situation. With these reasons, low frequency current ripple makes fuel cell system unstable and lifetime of fuel cell stack itself short. This paper presents a fast and robust control algorithm to eliminate low frequency current ripple in grid-connected fuel cell systems. Compared with the conventional methods, in the proposed control algorithm, dc link voltage controller is shifted from dc-dc converter to dc-ac inverter, resulting that dc-ac inverter handles dc link voltage control and output current control simultaneously with help of power balancing technique. The results indicate that the proposed algorithm can not only completely eliminate current ripple but also significantly reduce the overshoot or undershoot during transient states without any extra hardware. The validity of the proposed algorithm is verified by computer simulations and also by experiments with a 1 kW laboratory prototype. (author)

  5. Constrained Optimization Based on Hybrid Evolutionary Algorithm and Adaptive Constraint-Handling Technique

    DEFF Research Database (Denmark)

    Wang, Yong; Cai, Zixing; Zhou, Yuren

    2009-01-01

    A novel approach to deal with numerical and engineering constrained optimization problems, which incorporates a hybrid evolutionary algorithm and an adaptive constraint-handling technique, is presented in this paper. The hybrid evolutionary algorithm simultaneously uses simplex crossover and two...... mutation operators to generate the offspring population. Additionally, the adaptive constraint-handling technique consists of three main situations. In detail, at each situation, one constraint-handling mechanism is designed based on current population state. Experiments on 13 benchmark test functions...... and four well-known constrained design problems verify the effectiveness and efficiency of the proposed method. The experimental results show that integrating the hybrid evolutionary algorithm with the adaptive constraint-handling technique is beneficial, and the proposed method achieves competitive...

  6. An interactive tutorial-based training technique for vertebral morphometry.

    Science.gov (United States)

    Gardner, J C; von Ingersleben, G; Heyano, S L; Chesnut, C H

    2001-01-01

    The purpose of this work was to develop a computer-based procedure for training technologists in vertebral morphometry. The utility of the resulting interactive, tutorial based training method was evaluated in this study. The training program was composed of four steps: (1) review of an online tutorial, (2) review of analyzed spine images, (3) practice in fiducial point placement and (4) testing. During testing, vertebral heights were measured from digital, lateral spine images containing osteoporotic fractures. Inter-observer measurement precision was compared between research technicians, and between technologists and radiologist. The technologists participating in this study had no prior experience in vertebral morphometry. Following completion of the online training program, good inter-observer measurement precision was seen between technologists, showing mean coefficients of variation of 2.33% for anterior, 2.87% for central and 2.65% for posterior vertebral heights. Comparisons between the technicians and radiologist ranged from 2.19% to 3.18%. Slightly better precision values were seen with height measurements compared with height ratios, and with unfractured compared with fractured vertebral bodies. The findings of this study indicate that self-directed, tutorial-based training for spine image analyses is effective, resulting in good inter-observer measurement precision. The interactive tutorial-based approach provides standardized training methods and assures consistency of instructional technique over time.

  7. Research on Defects Inspection of Solder Balls Based on Eddy Current Pulsed Thermography

    Science.gov (United States)

    Zhou, Xiuyun; Zhou, Jinlong; Tian, Guiyun; Wang, Yizhe

    2015-01-01

    In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT). Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique. PMID:26473871

  8. Research on defects inspection of solder balls based on eddy current pulsed thermography.

    Science.gov (United States)

    Zhou, Xiuyun; Zhou, Jinlong; Tian, Guiyun; Wang, Yizhe

    2015-10-13

    In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT). Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique.

  9. Research on Defects Inspection of Solder Balls Based on Eddy Current Pulsed Thermography

    Directory of Open Access Journals (Sweden)

    Xiuyun Zhou

    2015-10-01

    Full Text Available In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT. Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique.

  10. Radiative neutron capture as a counting technique at pulsed spallation neutron sources: a review of current progress

    Science.gov (United States)

    Schooneveld, E. M.; Pietropaolo, A.; Andreani, C.; Perelli Cippo, E.; Rhodes, N. J.; Senesi, R.; Tardocchi, M.; Gorini, G.

    2016-09-01

    Neutron scattering techniques are attracting an increasing interest from scientists in various research fields, ranging from physics and chemistry to biology and archaeometry. The success of these neutron scattering applications is stimulated by the development of higher performance instrumentation. The development of new techniques and concepts, including radiative capture based neutron detection, is therefore a key issue to be addressed. Radiative capture based neutron detectors utilize the emission of prompt gamma rays after neutron absorption in a suitable isotope and the detection of those gammas by a photon counter. They can be used as simple counters in the thermal region and (simultaneously) as energy selector and counters for neutrons in the eV energy region. Several years of extensive development have made eV neutron spectrometers operating in the so-called resonance detector spectrometer (RDS) configuration outperform their conventional counterparts. In fact, the VESUVIO spectrometer, a flagship instrument at ISIS serving a continuous user programme for eV inelastic neutron spectroscopy measurements, is operating in the RDS configuration since 2007. In this review, we discuss the physical mechanism underlying the RDS configuration and the development of associated instrumentation. A few successful neutron scattering experiments that utilize the radiative capture counting techniques will be presented together with the potential of this technique for thermal neutron diffraction measurements. We also outline possible improvements and future perspectives for radiative capture based neutron detectors in neutron scattering application at pulsed neutron sources.

  11. PDMS microchannel fabrication technique based on microwire-molding

    Institute of Scientific and Technical Information of China (English)

    JIA YueFei; JIANG JiaHuan; MA XiaoDong; LI Yuan; HUANG HeMing; CAI KunBao; CAI ShaoXi; WU YunPeng

    2008-01-01

    Micro-flow channel is basic functional component of microfluidic chip, and every step-forward of its construction technique has been receiving concern all over the world. This article presents a notcomplicated but flexible method for fabrication of micro-flow channels. This method mainly utilizes the conventional molding capability of polydimethylsiloxane (PDMS) and widespread commercial microwires as templates. We have fabricated out some conventional types of microchannels with different topological shapes, as examples for the demonstration of this flexible fabrication route which was not dependent on the stringent demands of photolithographical or microelectromechanical system (MEMS)techniques. The smooth surface, high-intensity, and high flexibility of the wires made it possible to create many types of topological structures of the two-dimensional or three-dimensional microchannel or channel array. The geometric shape of the cross-section of thus forming microchannel in PDMS was the negative of that of embedded-in microwire, in high-fidelity if suitable measures were taken. Moreover, such a microchannel fabrication process can easily integrate the conductivity and low resistivity of the metal wire to create micro-flow devices that are suitable for the electromagnetic control of liquid or the temperature regulation in the microchannel. Furthermore some preliminary optical analysis was provided for the observation of thus forming rounded microchannel. Based on this molding strategy,we even made some prototypes for functional microflow application, such as microsolenoids chip and temperature control gadgets. And an experiment of forming a droplet in the cross channel further confirmed the feasibility and applicability of this flexible microchannel forming technique.

  12. Current status and future challenges for controlling malaria with the sterile insect technique: technical and social perspectives.

    Science.gov (United States)

    Oliva, Clelia F; Vreysen, Marc J B; Dupé, Sandrine; Lees, Rosemary S; Gilles, Jeremie R L; Gouagna, Louis-Clement; Chhem, Rethy

    2014-04-01

    The intolerable burden of malaria, when faced with high levels of drug resistance, increasing insecticide resistance and meagre resources at the national level, remains a great public health challenge to governments and the research/control community. Efficient control methods against the vectors of malaria are desperately needed. Control strategies for malaria that integrate the transfer of sterile sperm by released males to wild virgin females with other control tactics are currently being developed, and optimised mass-rearing, irradiation and release techniques are being validated in several field sites. However, the success of this strategy as part of wider pest control or health management programmes strongly depends on gaining public understanding and acceptance. Here we attempt to review what progress has been made and the remaining challenges surrounding the use of the sterile insect technique against malaria from technical and social perspectives. Copyright © 2013 International Atomic Energy Agency 2013. Published by Elsevier B.V. All rights reserved.

  13. From Research to Practice: Increasing Ability of Practitioners to Relate Family-of-Origin Communicative Techniques to Current Marital Satisfaction

    Directory of Open Access Journals (Sweden)

    Claire Kimberly

    2016-02-01

    Full Text Available Research has shown a connection between family-of-origin communicative techniques and later marital satisfaction. However, little has been done to see how this information can be incorporated in family life education settings. The purpose of this study is to make a connection between research and practice by testing the validity of easy-to-use measurements informing this relationship. The results of a survey from 649 married individuals about the communicative practices within their family-of-origin and in their current marriage support the ability of practitioners to understand techniques utilized in marriage by interpreting those used in childhood. By associating the literature between family-of-origin communication and marital dynamics in a practical way, practitioners and educators will be better able to assess and assist married couples in therapeutic or educational settings.

  14. Diagnosis of pedal osteomyelitis in diabetic patients using current scintigraphic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Keenan, A.M.; Tindel, N.L.; Alavi, A. (Hospital of the Univ. of Pennsylvania, Philadelphia (USA))

    1989-10-01

    Seventy-seven diabetic patients with suspected osteomyelitis of the foot were evaluated by three-phase bone scintigraphy (TPBS), indium 111-labeled white blood cell scintigraphy (WBCS), roentgenography, or some combination thereof. Retrospective analysis after clinical and pathologic follow-up indicated that the sensitivity of TPBS alone in the diagnosis of osteomyelitis was 100%, with a specificity of only 38% and an accuracy of 63%; the sensitivity of WBCS alone was 100%, with a specificity of 78% and an accuracy of 87%; and the combination of TPBS and WBCS yielded a sensitivity of 100%, with a specificity of 79% and an accuracy of 87%. Roentgenography yielded a sensitivity of 69%, with a specificity of 82% and an accuracy of 76%. The results of this study demonstrate that WBCS is superior to TPBS in the diagnosis of osteomyelitis in the diabetic foot, and TPBS adds little when viewed in conjunction with WBCS. Based on our observations and because of the high prevalence of neuropathic joint disease and other causes of false-positive bone scans, we believe that WBCS alone is adequate for evaluation of suspected pedal osteomyelitis in diabetic patients, particularly when the suspected lesion is located in the tarsometatarsal region in contrast to the toe region (7% vs 44% specificity and 28% vs 69% accuracy, respectively, for TPBS in these two regions, compared with 100% vs 68% specificity and 100% vs 80% accuracy, respectively, for WBCS in the same two regions).

  15. A novel current-sharing scheme based on magamp

    Institute of Scientific and Technical Information of China (English)

    Wen-xi YAO; Xiao-yuan HONG; Zheng-yu LU

    2008-01-01

    The magamp (magnetic amplifier) is widely used in power supplies due to its low cost,simplicity and other advantages.This paper discusses a novel application of the magamp in switching power supplies,where the magamp is used to regulate pulse width modulation (PWM) instead of power signal in the main circuit.This method extends the application of the magamp in power supplies,and makes it possible to further regulate control signal when PWMs have been generated.Based on this application,a new current-sharing (CS) scheme using the magamp is proposed,which uses a modified inner loop CS structure.In this scheme PWMs are generated by one main controller,and CS is achieved by regulating PWMs using a magamp in each module.Compared with traditional application of the magamp,the new CS scheme can be used in most topologies and only requires magamps of low power capacity.Then a test circuit of parallel power supply is developed,in which CS is achieved by a PWM regulator with the magamp.The proposed scheme is also used to upgrade an electroplate power to make it capable of paralleling supplies.Experimental results show that the proposed scheme has good CS performance.

  16. The drive to strive: goal generation based on current needs

    Directory of Open Access Journals (Sweden)

    Elisabeth A Murray

    2013-06-01

    Full Text Available Hungry animals are influenced by a multitude of different factors when foraging for sustenance. Much of the work on animal foraging has focused on factors relating to the amount of time and energy animals expend searching for and harvesting foods. Models that emphasize such factors have been invaluable in determining when it is beneficial for an animal to search for pastures new. When foraging, however, animals also have to determine how to direct their search. For what food should they forage? There is no point searching for more of a particular food when you are sated from eating it. Here we review work in macaques and humans that has sought to reveal the neural circuits critical for determining the subjective value of different foods and associated objects in our environment and tracking this value over time. There is mounting evidence that a network composed of the orbitofrontal cortex (OFC, amygdala and medial thalamus is critical for linking objects in the environment with food value and adjusting those valuations in real time based on current biological needs. Temporal inactivation studies have revealed that the amygdala and OFC play distinct, but complementary roles in this valuation process. Such a network for determining the subjective value of different foods and, by extension, associated objects, must interact with systems that determine where and for how long to forage. Only by efficiently incorporating these two factors into their decisions will animals be able to achieve maximal fitness.

  17. Current Treatment of Toxoplasma Retinochoroiditis: An Evidence-Based Review

    Directory of Open Access Journals (Sweden)

    Meredith Harrell

    2014-01-01

    Full Text Available Objective. To perform an evidence-based review of treatments for Toxoplasma retinochoroiditis (TRC. Methods. A systematic literature search was performed using the PubMed database and the key phrase “ocular toxoplasmosis treatment” and the filter for “controlled clinical trial” and “randomized clinical trial” as well as OVID medline (1946 to May week 2 2014 using the keyword ‘‘ocular toxoplasmosis’’. The included studies were used to evaluate the various treatment modalities of TRC. Results. The electronic search yielded a total of 974 publications of which 44 reported on the treatment of ocular toxoplasmosis. There were 9 randomized controlled studies and an additional 3 comparative studies on the treatment of acute TRC with systemic or intravitreous antibiotics or on reducing the recurrences of TRC. Endpoints of studies included visual acuity improvement, inflammatory response, lesion size changes, recurrences of lesions, and adverse effects of medications. Conclusions. There was conflicting evidence as to the effectiveness of systemic antibiotics for TRC. There is no evidence to support that one antibiotic regimen is superior to another so choice needs to be informed by the safety profile. Intravitreous clindamycin with dexamethasone seems to be as effective as systemic treatments. There is currently level I evidence that intermittent trimethoprim-sulfamethoxazole prevents recurrence of the disease.

  18. Twisted Savonius turbine based marine current energy conversion system

    Science.gov (United States)

    Hassan, Md. Imtiaj

    The Ocean Network Seafloor Instrumentation (ONSFI) Project is a multidisciplinary research and development project that aims to design, fabricate and validate a proof-of-concept seafloor array of wireless marine sensors for use in monitoring seabed processes. The sensor pods, known as Seaformatics, will be powered by ocean bottom currents and will be able to communicate with each other and to the Internet through surface master units to facilitate observation of the ocean floor from the shore. This thesis explores the use of the twisted Savonius turbine as a means of converting the kinetic energy of the free flowing water into electrical energy for the pods. This will eliminate the need for battery replacement. A physical model of the turbine was constructed and tested in the Water Flume at the Marine Institute of Memorial University and in the Wind Tunnel in the Engineering Building at Memorial University. A mathematical model of the turbine was constructed in SolidWorks. This was tested in the Computational Fluid Dynamics or CFD software FLOW-3D. Experimental results were compared with CFD results and the agreement was reasonable. A twisted Savonius turbine emulator was developed to test a dc-dc boost converter. A low cost microcontroller based MPPT algorithm was developed to obtain maximum power from the turbine. Overall the thesis shows that the twisted Savonius turbine can provide the power needed by the sensor pods. It also shows that CFD is a viable way to study the performance of the Savonius type of turbine.

  19. A survey of GPU-based medical image computing techniques.

    Science.gov (United States)

    Shi, Lin; Liu, Wen; Zhang, Heye; Xie, Yongming; Wang, Defeng

    2012-09-01

    Medical imaging currently plays a crucial role throughout the entire clinical applications from medical scientific research to diagnostics and treatment planning. However, medical imaging procedures are often computationally demanding due to the large three-dimensional (3D) medical datasets to process in practical clinical applications. With the rapidly enhancing performances of graphics processors, improved programming support, and excellent price-to-performance ratio, the graphics processing unit (GPU) has emerged as a competitive parallel computing platform for computationally expensive and demanding tasks in a wide range of medical image applications. The major purpose of this survey is to provide a comprehensive reference source for the starters or researchers involved in GPU-based medical image processing. Within this survey, the continuous advancement of GPU computing is reviewed and the existing traditional applications in three areas of medical image processing, namely, segmentation, registration and visualization, are surveyed. The potential advantages and associated challenges of current GPU-based medical imaging are also discussed to inspire future applications in medicine.

  20. Extrusion based rapid prototyping technique: an advanced platform for tissue engineering scaffold fabrication.

    Science.gov (United States)

    Hoque, M Enamul; Chuan, Y Leng; Pashby, Ian

    2012-02-01

    Advances in scaffold design and fabrication technology have brought the tissue engineering field stepping into a new era. Conventional techniques used to develop scaffolds inherit limitations, such as lack of control over the pore morphology and architecture as well as reproducibility. Rapid prototyping (RP) technology, a layer-by-layer additive approach offers a unique opportunity to build complex 3D architectures overcoming those limitations that could ultimately be tailored to cater for patient-specific applications. Using RP methods, researchers have been able to customize scaffolds to mimic the biomechanical properties (in terms of structural integrity, strength, and microenvironment) of the organ or tissue to be repaired/replaced quite closely. This article provides intensive description on various extrusion based scaffold fabrication techniques and review their potential utility for TE applications. The extrusion-based technique extrudes the molten polymer as a thin filament through a nozzle onto a platform layer-by-layer and thus building 3D scaffold. The technique allows full control over pore architecture and dimension in the x- and y- planes. However, the pore height in z-direction is predetermined by the extruding nozzle diameter rather than the technique itself. This review attempts to assess the current state and future prospects of this technology.

  1. NVC Based Model for Selecting Effective Requirement Elicitation Technique

    Directory of Open Access Journals (Sweden)

    Md. Rizwan Beg

    2012-10-01

    Full Text Available Requirement Engineering process starts from gathering of requirements i.e.; requirements elicitation. Requirementselicitation (RE is the base building block for a software project and has very high impact onsubsequent design and builds phases as well. Accurately capturing system requirements is the major factorin the failure of most of software projects. Due to the criticality and impact of this phase, it is very importantto perform the requirements elicitation in no less than a perfect manner. One of the most difficult jobsfor elicitor is to select appropriate technique for eliciting the requirement. Interviewing and Interactingstakeholder during Elicitation process is a communication intensive activity involves Verbal and Nonverbalcommunication (NVC. Elicitor should give emphasis to Non-verbal communication along with verbalcommunication so that requirements recorded more efficiently and effectively. In this paper we proposea model in which stakeholders are classified by observing non-verbal communication and use it as a basefor elicitation technique selection. We also propose an efficient plan for requirements elicitation which intendsto overcome on the constraints, faced by elicitor.

  2. Filling-Based Techniques Applied to Object Projection Feature Estimation

    CERN Document Server

    Quesada, Luis

    2012-01-01

    3D motion tracking is a critical task in many computer vision applications. Unsupervised markerless 3D motion tracking systems determine the most relevant object in the screen and then track it by continuously estimating its projection features (center and area) from the edge image and a point inside the relevant object projection (namely, inner point), until the tracking fails. Existing object projection feature estimation techniques are based on ray-casting from the inner point. These techniques present three main drawbacks: when the inner point is surrounded by edges, rays may not reach other relevant areas; as a consequence of that issue, the estimated features may greatly vary depending on the position of the inner point relative to the object projection; and finally, increasing the number of rays being casted and the ray-casting iterations (which would make the results more accurate and stable) increases the processing time to the point the tracking cannot be performed on the fly. In this paper, we anal...

  3. Model-checking techniques based on cumulative residuals.

    Science.gov (United States)

    Lin, D Y; Wei, L J; Ying, Z

    2002-03-01

    Residuals have long been used for graphical and numerical examinations of the adequacy of regression models. Conventional residual analysis based on the plots of raw residuals or their smoothed curves is highly subjective, whereas most numerical goodness-of-fit tests provide little information about the nature of model misspecification. In this paper, we develop objective and informative model-checking techniques by taking the cumulative sums of residuals over certain coordinates (e.g., covariates or fitted values) or by considering some related aggregates of residuals, such as moving sums and moving averages. For a variety of statistical models and data structures, including generalized linear models with independent or dependent observations, the distributions of these stochastic processes tinder the assumed model can be approximated by the distributions of certain zero-mean Gaussian processes whose realizations can be easily generated by computer simulation. Each observed process can then be compared, both graphically and numerically, with a number of realizations from the Gaussian process. Such comparisons enable one to assess objectively whether a trend seen in a residual plot reflects model misspecification or natural variation. The proposed techniques are particularly useful in checking the functional form of a covariate and the link function. Illustrations with several medical studies are provided.

  4. Investigations on landmine detection by neutron-based techniques.

    Science.gov (United States)

    Csikai, J; Dóczi, R; Király, B

    2004-07-01

    Principles and techniques of some neutron-based methods used to identify the antipersonnel landmines (APMs) are discussed. New results have been achieved in the field of neutron reflection, transmission, scattering and reaction techniques. Some conclusions are as follows: The neutron hand-held detector is suitable for the observation of anomaly caused by a DLM2-like sample in different soils with a scanning speed of 1m(2)/1.5 min; the reflection cross section of thermal neutrons rendered the determination of equivalent thickness of different soil components possible; a simple method was developed for the determination of the thermal neutron flux perturbation factor needed for multi-elemental analysis of bulky samples; unfolded spectra of elastically backscattered neutrons using broad-spectrum sources render the identification of APMs possible; the knowledge of leakage spectra of different source neutrons is indispensable for the determination of the differential and integrated reaction rates and through it the dimension of the interrogated volume; the precise determination of the C/O atom fraction requires the investigations on the angular distribution of the 6.13MeV gamma-ray emitted in the (16)O(n,n'gamma) reaction. These results, in addition to the identification of landmines, render the improvement of the non-intrusive neutron methods possible.

  5. Investigations on landmine detection by neutron-based techniques

    Energy Technology Data Exchange (ETDEWEB)

    Csikai, J. E-mail: csikai@delfin.klte.hu; Doczi, R.; Kiraly, B

    2004-07-01

    Principles and techniques of some neutron-based methods used to identify the antipersonnel landmines (APMs) are discussed. New results have been achieved in the field of neutron reflection, transmission, scattering and reaction techniques. Some conclusions are as follows: The neutron hand-held detector is suitable for the observation of anomaly caused by a DLM2-like sample in different soils with a scanning speed of 1 m{sup 2}/1.5 min; the reflection cross section of thermal neutrons rendered the determination of equivalent thickness of different soil components possible; a simple method was developed for the determination of the thermal neutron flux perturbation factor needed for multi-elemental analysis of bulky samples; unfolded spectra of elastically backscattered neutrons using broad-spectrum sources render the identification of APMs possible; the knowledge of leakage spectra of different source neutrons is indispensable for the determination of the differential and integrated reaction rates and through it the dimension of the interrogated volume; the precise determination of the C/O atom fraction requires the investigations on the angular distribution of the 6.13 MeV gamma-ray emitted in the {sup 16}O(n,n'{gamma}) reaction. These results, in addition to the identification of landmines, render the improvement of the non-intrusive neutron methods possible.

  6. A human visual based binarization technique for histological images

    Science.gov (United States)

    Shreyas, Kamath K. M.; Rajendran, Rahul; Panetta, Karen; Agaian, Sos

    2017-05-01

    In the field of vision-based systems for object detection and classification, thresholding is a key pre-processing step. Thresholding is a well-known technique for image segmentation. Segmentation of medical images, such as Computed Axial Tomography (CAT), Magnetic Resonance Imaging (MRI), X-Ray, Phase Contrast Microscopy, and Histological images, present problems like high variability in terms of the human anatomy and variation in modalities. Recent advances made in computer-aided diagnosis of histological images help facilitate detection and classification of diseases. Since most pathology diagnosis depends on the expertise and ability of the pathologist, there is clearly a need for an automated assessment system. Histological images are stained to a specific color to differentiate each component in the tissue. Segmentation and analysis of such images is problematic, as they present high variability in terms of color and cell clusters. This paper presents an adaptive thresholding technique that aims at segmenting cell structures from Haematoxylin and Eosin stained images. The thresholded result can further be used by pathologists to perform effective diagnosis. The effectiveness of the proposed method is analyzed by visually comparing the results to the state of art thresholding methods such as Otsu, Niblack, Sauvola, Bernsen, and Wolf. Computer simulations demonstrate the efficiency of the proposed method in segmenting critical information.

  7. A New Particle Swarm Optimization Based Stock Market Prediction Technique

    Directory of Open Access Journals (Sweden)

    Essam El. Seidy

    2016-04-01

    Full Text Available Over the last years, the average person's interest in the stock market has grown dramatically. This demand has doubled with the advancement of technology that has opened in the International stock market, so that nowadays anybody can own stocks, and use many types of software to perform the aspired profit with minimum risk. Consequently, the analysis and prediction of future values and trends of the financial markets have got more attention, and due to large applications in different business transactions, stock market prediction has become a critical topic of research. In this paper, our earlier presented particle swarm optimization with center of mass technique (PSOCoM is applied to the task of training an adaptive linear combiner to form a new stock market prediction model. This prediction model is used with some common indicators to maximize the return and minimize the risk for the stock market. The experimental results show that the proposed technique is superior than the other PSO based models according to the prediction accuracy.

  8. Detecting Molecular Properties by Various Laser-Based Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hsin, Tse-Ming [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Four different laser-based techniques were applied to study physical and chemical characteristics of biomolecules and dye molecules. These techniques are liole burning spectroscopy, single molecule spectroscopy, time-resolved coherent anti-Stokes Raman spectroscopy and laser-induced fluorescence microscopy. Results from hole burning and single molecule spectroscopy suggested that two antenna states (C708 & C714) of photosystem I from cyanobacterium Synechocystis PCC 6803 are connected by effective energy transfer and the corresponding energy transfer time is ~6 ps. In addition, results from hole burning spectroscopy indicated that the chlorophyll dimer of the C714 state has a large distribution of the dimer geometry. Direct observation of vibrational peaks and evolution of coumarin 153 in the electronic excited state was demonstrated by using the fs/ps CARS, a variation of time-resolved coherent anti-Stokes Raman spectroscopy. In three different solvents, methanol, acetonitrile, and butanol, a vibration peak related to the stretch of the carbonyl group exhibits different relaxation dynamics. Laser-induced fluorescence microscopy, along with the biomimetic containers-liposomes, allows the measurement of the enzymatic activity of individual alkaline phosphatase from bovine intestinal mucosa without potential interferences from glass surfaces. The result showed a wide distribution of the enzyme reactivity. Protein structural variation is one of the major reasons that are responsible for this highly heterogeneous behavior.

  9. Long RE123 coated conductors with high critical current over 500 A/cm by IBAD/PLD technique

    Energy Technology Data Exchange (ETDEWEB)

    Kakimoto, K., E-mail: kkakimoto@fujikura.co.jp [Fujikura Ltd., 1440, Mutsuzaki, Sakura, Chiba 285-8550 (Japan); Igarashi, M.; Hanyu, S.; Sutoh, Y.; Takemoto, T.; Hayashida, T.; Hanada, Y.; Nakamura, N.; Kikutake, R.; Kutami, H.; Iijima, Y.; Saitoh, T. [Fujikura Ltd., 1440, Mutsuzaki, Sakura, Chiba 285-8550 (Japan)

    2011-11-15

    We have developed long RE123 coated conductors with large current capacity by IBAD and HW-PLD technique. We could fabricate an 8 m-long Gd123 coated wire with the I{sub c} of over 900 A/cm-w at 77 K, 0 T. We set the new world record of I{sub c} x L value as 374535 A m (= 609 A x 615 m). We have developed long RE{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-X} (RE123) coated conductors with large current capacity by the ion beam assisted deposition (IBAD) and the pulsed laser deposition using hot wall heating (HW-PLD) technique. As a result, we could fabricate an 8 m-long Gd{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-X} (Gd123) coated wire with the minimum and maximum critical current (I{sub c}) of 951 A/cm-w and 1003 A/cm-w at 77 K, 0 T, respectively, measured in 0.7 m-long sections by the standard 4-probe technique. Furthermore, we succeeded in preparation of over 600 m-long Gd123 coated wire with the uniform I{sub c} distribution over 600 A/cm-w. It had average, maximum and minimum I{sub c} of 665, 698, 609 A/cm-w, respectively. The n-values of the sample showed the maximum I{sub c} and minimum I{sub c} were 40 and 36, respectively. As a result, we set the new world record of I{sub c} x L value as 374535 A m (= 609 A x 615 m). The in-field performance of this long wire was quite high as well; the minimum I{sub c} exceeded 50 A/cm-w at 77 K, 3 T.

  10. Current breathomics-a review on data pre-processing techniques and machine learning in metabolomics breath analysis

    DEFF Research Database (Denmark)

    Smolinska, A.; Hauschild, A. C.; Fijten, R. R. R.

    2014-01-01

    been extensively developed. Yet, the application of machine learning methods for fingerprinting VOC profiles in the breathomics is still in its infancy. Therefore, in this paper, we describe the current state of the art in data pre-processing and multivariate analysis of breathomics data. We start...... different conditions (e.g. disease stage, treatment). Independently of the utilized analytical method, the most important question, 'which VOCs are discriminatory?', remains the same. Answers can be given by several modern machine learning techniques (multivariate statistics) and, therefore, are the focus...

  11. A Technique to Estimate the Equivalent Loss Resistance of Grid-Tied Converters for Current Control Analysis and Design

    DEFF Research Database (Denmark)

    Vidal, Ana; Yepes, Alejandro G.; Fernandez, Francisco Daniel Freijedo

    2015-01-01

    Rigorous analysis and design of the current control loop in voltage source converters (VSCs) requires an accurate modeling. The loop behavior can be significantly influenced by the VSC working conditions. To consider such effect, converter losses should be included in the model, which can be done...... by means of an equivalent series resistance. This paper proposes a method to identify the VSC equivalent loss resistance for the proper tuning of the current control loop. It is based on analysis of the closed-loop transient response provided by a synchronous proportional-integral current controller......, according to the internal model principle. The method gives a set of loss resistance values linked to working conditions, which can be used to improve the tuning of the current controllers, either by online adaptation of the controller gains or by open-loop adaptive adjustment of them according to prestored...

  12. An RSS based location estimation technique for cognitive relay networks

    KAUST Repository

    Qaraqe, Khalid A.

    2010-11-01

    In this paper, a received signal strength (RSS) based location estimation method is proposed for a cooperative wireless relay network where the relay is a cognitive radio. We propose a method for the considered cognitive relay network to determine the location of the source using the direct and the relayed signal at the destination. We derive the Cramer-Rao lower bound (CRLB) expressions separately for x and y coordinates of the location estimate. We analyze the effects of cognitive behaviour of the relay on the performance of the proposed method. We also discuss and quantify the reliability of the location estimate using the proposed technique if the source is not stationary. The overall performance of the proposed method is presented through simulations. ©2010 IEEE.

  13. A 3-Level Secure Histogram Based Image Steganography Technique

    Directory of Open Access Journals (Sweden)

    G V Chaitanya

    2013-04-01

    Full Text Available Steganography is an art that involves communication of secret data in an appropriate carrier, eg. images, audio, video, etc. with a goal to hide the very existence of embedded data so as not to arouse an eavesdropper’s suspicion. In this paper, a steganographic technique with high level of security and having a data hiding capacity close to 20% of cover image data has been developed. An adaptive and matched bit replacement method is used based on the sensitivity of Human Visual System (HVS at different intensities. The proposed algorithm ensures that the generated stego image has a PSNR greater than 38.5 and is also resistant to visual attack. A three level security is infused into the algorithm which makes data retrieval from the stego image possible only in case of having all the right keys.

  14. Proposed Arabic Text Steganography Method Based on New Coding Technique

    Directory of Open Access Journals (Sweden)

    Assist. prof. Dr. Suhad M. Kadhem

    2016-09-01

    Full Text Available Steganography is one of the important fields of information security that depend on hiding secret information in a cover media (video, image, audio, text such that un authorized person fails to realize its existence. One of the lossless data compression techniques which are used for a given file that contains many redundant data is run length encoding (RLE. Sometimes the RLE output will be expanded rather than compressed, and this is the main problem of RLE. In this paper we will use a new coding method such that its output will be contains sequence of ones with few zeros, so modified RLE that we proposed in this paper will be suitable for compression, finally we employ the modified RLE output for stenography purpose that based on Unicode and non-printed characters to hide the secret information in an Arabic text.

  15. Clustering economies based on multiple criteria decision making techniques

    Directory of Open Access Journals (Sweden)

    Mansour Momeni

    2011-10-01

    Full Text Available One of the primary concerns on many countries is to determine different important factors affecting economic growth. In this paper, we study some factors such as unemployment rate, inflation ratio, population growth, average annual income, etc to cluster different countries. The proposed model of this paper uses analytical hierarchy process (AHP to prioritize the criteria and then uses a K-mean technique to cluster 59 countries based on the ranked criteria into four groups. The first group includes countries with high standards such as Germany and Japan. In the second cluster, there are some developing countries with relatively good economic growth such as Saudi Arabia and Iran. The third cluster belongs to countries with faster rates of growth compared with the countries located in the second group such as China, India and Mexico. Finally, the fourth cluster includes countries with relatively very low rates of growth such as Jordan, Mali, Niger, etc.

  16. Crop Yield Forecasted Model Based on Time Series Techniques

    Institute of Scientific and Technical Information of China (English)

    Li Hong-ying; Hou Yan-lin; Zhou Yong-juan; Zhao Hui-ming

    2012-01-01

    Traditional studies on potential yield mainly referred to attainable yield: the maximum yield which could be reached by a crop in a given environment. The new concept of crop yield under average climate conditions was defined in this paper, which was affected by advancement of science and technology. Based on the new concept of crop yield, the time series techniques relying on past yield data was employed to set up a forecasting model. The model was tested by using average grain yields of Liaoning Province in China from 1949 to 2005. The testing combined dynamic n-choosing and micro tendency rectification, and an average forecasting error was 1.24%. In the trend line of yield change, and then a yield turning point might occur, in which case the inflexion model was used to solve the problem of yield turn point.

  17. A polarization-based Thomson scattering technique for burning plasmas

    CERN Document Server

    Parke, E; Hartog, D J Den

    2013-01-01

    The traditional Thomson scattering diagnostic is based on measurement of the wavelength spectrum of scattered light, where electron temperature measurements are inferred from thermal broadening of the scattered laser light. At sufficiently high temperatures, especially those predicted for ITER and other burning plasmas, relativistic effects cause a change in the polarization state of the scattered photons. The resulting depolarization of the scattered light is temperature dependent and has been proposed elsewhere as a potential alternative to the traditional spectral decomposition technique. Following similar work, we analytically calculate the degree of polarization for incoherent Thomson scattering. For the first time, we obtain exact results valid for the full range of incident laser polarization states and electron temperatures. While previous work focused only on linear polarization, we show that circularly polarized incident light optimizes the degree of depolarization for a wide range of temperatures r...

  18. SAR IMAGE ENHANCEMENT BASED ON BEAM SHARPENING TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    LIYong; ZI-IANGKun-hui; ZHUDai-yin; ZHUZhao-da

    2004-01-01

    A major problem encountered in enhancing SAR image is the total loss of phase information and the unknown parameters of imaging system. The beam sharpening technique, combined with synthetic aperture radiation pattern estimation provides an approach to process this kind of data to achieve higher apparent resolution. Based on the criterion of minimizing the expected quadratic estimation error, an optimum FIR filter with a symmetrical structure is designed whose coefficients depend on the azimuth response of local isolated prominent points because this response can be approximately regarded as the synthetic aperture radiation pattern of the imaging system. The point target simulation shows that the angular resolution is improved by a ratio of almost two to one. The processing results of a live SAR image demonstrate the validity of the method.

  19. Dynamic analysis of granite rockburst based on the PIV technique

    Institute of Scientific and Technical Information of China (English)

    Wang Hongjian; Liu Da’an; Gong Weili; Li Liyun

    2015-01-01

    This paper describes the deep rockburst simulation system to reproduce the granite instantaneous rock-burst process. Based on the PIV (Particle Image Velocimetry) technique, quantitative analysis of a rock-burst, the images of tracer particle, displacement and strain fields can be obtained, and the debris trajectory described. According to the observation of on-site tests, the dynamic rockburst is actually a gas–solid high speed flow process, which is caused by the interaction of rock fragments and surrounding air. With the help of analysis on high speed video and PIV images, the granite rockburst failure process is composed of six stages of platey fragment spalling and debris ejection. Meanwhile, the elastic energy for these six stages has been calculated to study the energy variation. The results indicate that the rockburst process can be summarized as:an initiating stage, intensive developing stage and gradual decay stage. This research will be helpful for our further understanding of the rockburst mechanism.

  20. Hierarchical Spread Spectrum Fingerprinting Scheme Based on the CDMA Technique

    Directory of Open Access Journals (Sweden)

    Kuribayashi Minoru

    2011-01-01

    Full Text Available Abstract Digital fingerprinting is a method to insert user's own ID into digital contents in order to identify illegal users who distribute unauthorized copies. One of the serious problems in a fingerprinting system is the collusion attack such that several users combine their copies of the same content to modify/delete the embedded fingerprints. In this paper, we propose a collusion-resistant fingerprinting scheme based on the CDMA technique. Our fingerprint sequences are orthogonal sequences of DCT basic vectors modulated by PN sequence. In order to increase the number of users, a hierarchical structure is produced by assigning a pair of the fingerprint sequences to a user. Under the assumption that the frequency components of detected sequences modulated by PN sequence follow Gaussian distribution, the design of thresholds and the weighting of parameters are studied to improve the performance. The robustness against collusion attack and the computational costs required for the detection are estimated in our simulation.

  1. Demand Management Based on Model Predictive Control Techniques

    Directory of Open Access Journals (Sweden)

    Yasser A. Davizón

    2014-01-01

    Full Text Available Demand management (DM is the process that helps companies to sell the right product to the right customer, at the right time, and for the right price. Therefore the challenge for any company is to determine how much to sell, at what price, and to which market segment while maximizing its profits. DM also helps managers efficiently allocate undifferentiated units of capacity to the available demand with the goal of maximizing revenue. This paper introduces control system approach to demand management with dynamic pricing (DP using the model predictive control (MPC technique. In addition, we present a proper dynamical system analogy based on active suspension and a stability analysis is provided via the Lyapunov direct method.

  2. Whitelists Based Multiple Filtering Techniques in SCADA Sensor Networks

    Directory of Open Access Journals (Sweden)

    DongHo Kang

    2014-01-01

    Full Text Available Internet of Things (IoT consists of several tiny devices connected together to form a collaborative computing environment. Recently IoT technologies begin to merge with supervisory control and data acquisition (SCADA sensor networks to more efficiently gather and analyze real-time data from sensors in industrial environments. But SCADA sensor networks are becoming more and more vulnerable to cyber-attacks due to increased connectivity. To safely adopt IoT technologies in the SCADA environments, it is important to improve the security of SCADA sensor networks. In this paper we propose a multiple filtering technique based on whitelists to detect illegitimate packets. Our proposed system detects the traffic of network and application protocol attacks with a set of whitelists collected from normal traffic.

  3. A Novel Technique Based on Node Registration in MANETs

    Directory of Open Access Journals (Sweden)

    Rashid Jalal Qureshi

    2012-09-01

    Full Text Available In ad hoc network communication links between the nodes are wireless and each node acts as a router for the other node and packet is forward from one node to other. This type of networks helps in solving challenges and problems that may arise in every day communication. Mobile Ad Hoc Networks is a new field of research and it is particularly useful in situations where network infrastructure is costly. Protecting MANETs from security threats is a challenging task because of the MANETs dynamic topology. Every node in a MANETs is independent and is free to move in any direction, therefore change its connections to other nodes frequently. Due to its decentralized nature different types of attacks can be occur. The aim of this research paper is to investigate different MANETs security attacks and proposed nodes registration based technique by using cryptography functions.

  4. Astronomical Image Compression Techniques Based on ACC and KLT Coder

    Directory of Open Access Journals (Sweden)

    J. Schindler

    2011-01-01

    Full Text Available This paper deals with a compression of image data in applications in astronomy. Astronomical images have typical specific properties — high grayscale bit depth, size, noise occurrence and special processing algorithms. They belong to the class of scientific images. Their processing and compression is quite different from the classical approach of multimedia image processing. The database of images from BOOTES (Burst Observer and Optical Transient Exploring System has been chosen as a source of the testing signal. BOOTES is a Czech-Spanish robotic telescope for observing AGN (active galactic nuclei and the optical transient of GRB (gamma ray bursts searching. This paper discusses an approach based on an analysis of statistical properties of image data. A comparison of two irrelevancy reduction methods is presented from a scientific (astrometric and photometric point of view. The first method is based on a statistical approach, using the Karhunen-Loeve transform (KLT with uniform quantization in the spectral domain. The second technique is derived from wavelet decomposition with adaptive selection of used prediction coefficients. Finally, the comparison of three redundancy reduction methods is discussed. Multimedia format JPEG2000 and HCOMPRESS, designed especially for astronomical images, are compared with the new Astronomical Context Coder (ACC coder based on adaptive median regression.

  5. A microcomputer based system for current-meter data acquisition

    Science.gov (United States)

    Cheng, R.T.; Gartner, J.W.

    1979-01-01

    The U.S. Geological Survey is conducting current measurements as part of an interdisciplinary study of the San Francisco Bay estuarine system. The current meters used in the study record current speed, direction, temperature, and conductivity in digital codes on magnetic tape cartridges. Upon recovery of the current meters, the data tapes are translated by a tape reader into computer codes for further analyses. Quite often the importance of the data processing phase of a current-measurement program is underestimated and downplayed. In this paper a data-processing system which performs the complete data processing and analyses is described. The system, which is configured around an LSI-11 microcomputer, has been assembled to provide the capabilities of data translation, reduction, and tabulation and graphical display immediately following recovery of current meters. The flexibility inherent in a microcomputer has made it available to perform many other research functions which would normally be done on an institutional computer.

  6. Ionospheric Plasma Drift Analysis Technique Based On Ray Tracing

    Science.gov (United States)

    Ari, Gizem; Toker, Cenk

    2016-07-01

    Ionospheric drift measurements provide important information about the variability in the ionosphere, which can be used to quantify ionospheric disturbances caused by natural phenomena such as solar, geomagnetic, gravitational and seismic activities. One of the prominent ways for drift measurement depends on instrumentation based measurements, e.g. using an ionosonde. The drift estimation of an ionosonde depends on measuring the Doppler shift on the received signal, where the main cause of Doppler shift is the change in the length of the propagation path of the signal between the transmitter and the receiver. Unfortunately, ionosondes are expensive devices and their installation and maintenance require special care. Furthermore, the ionosonde network over the world or even Europe is not dense enough to obtain a global or continental drift map. In order to overcome the difficulties related to an ionosonde, we propose a technique to perform ionospheric drift estimation based on ray tracing. First, a two dimensional TEC map is constructed by using the IONOLAB-MAP tool which spatially interpolates the VTEC estimates obtained from the EUREF CORS network. Next, a three dimensional electron density profile is generated by inputting the TEC estimates to the IRI-2015 model. Eventually, a close-to-real situation electron density profile is obtained in which ray tracing can be performed. These profiles can be constructed periodically with a period of as low as 30 seconds. By processing two consequent snapshots together and calculating the propagation paths, we estimate the drift measurements over any coordinate of concern. We test our technique by comparing the results to the drift measurements taken at the DPS ionosonde at Pruhonice, Czech Republic. This study is supported by TUBITAK 115E915 and Joint TUBITAK 114E092 and AS CR14/001 projects.

  7. A CURRENT MIRROR BASED TWO STAGE CMOS CASCODE OP-AMP FOR HIGH FREQUENCY APPLICATION

    Directory of Open Access Journals (Sweden)

    RAMKRISHNA KUNDU

    2017-03-01

    Full Text Available This paper presents a low power, high slew rate, high gain, ultra wide band two stage CMOS cascode operational amplifier for radio frequency application. Current mirror based cascoding technique and pole zero cancelation technique is used to ameliorate the gain and enhance the unity gain bandwidth respectively, which is the novelty of the circuit. In cascading technique a common source transistor drive a common gate transistor. The cascoding is used to enhance the output resistance and hence improve the overall gain of the operational amplifier with less complexity and less power dissipation. To bias the common gate transistor, a current mirror is used in this paper. The proposed circuit is designed and simulated using Cadence analog and digital system design tools of 45 nanometer CMOS technology. The simulated results of the circuit show DC gain of 63.62 dB, unity gain bandwidth of 2.70 GHz, slew rate of 1816 V/µs, phase margin of 59.53º, power supply of the proposed operational amplifier is 1.4 V (rail-to-rail ±700 mV, and power consumption is 0.71 mW. This circuit specification has encountered the requirements of radio frequency application.

  8. Advanced Multipath Mitigation Techniques for Satellite-Based Positioning Applications

    Directory of Open Access Journals (Sweden)

    Mohammad Zahidul H. Bhuiyan

    2010-01-01

    Full Text Available Multipath remains a dominant source of ranging errors in Global Navigation Satellite Systems (GNSS, such as the Global Positioning System (GPS or the future European satellite navigation system Galileo. Multipath is generally considered undesirable in the context of GNSS, since the reception of multipath can make significant distortion to the shape of the correlation function used for time delay estimation. However, some wireless communications techniques exploit multipath in order to provide signal diversity though in GNSS, the major challenge is to effectively mitigate the multipath, since we are interested only in the satellite-receiver transit time offset of the Line-Of-Sight (LOS signal for the receiver's position estimate. Therefore, the multipath problem has been approached from several directions in order to mitigate the impact of multipath on navigation receivers, including the development of novel signal processing techniques. In this paper, we propose a maximum likelihood-based technique, namely, the Reduced Search Space Maximum Likelihood (RSSML delay estimator, which is capable of mitigating the multipath effects reasonably well at the expense of increased complexity. The proposed RSSML attempts to compensate the multipath error contribution by performing a nonlinear curve fit on the input correlation function, which finds a perfect match from a set of ideal reference correlation functions with certain amplitude(s, phase(s, and delay(s of the multipath signal. It also incorporates a threshold-based peak detection method, which eventually reduces the code-delay search space significantly. However, the downfall of RSSML is the memory requirement which it uses to store the reference correlation functions. The multipath performance of other delay-tracking methods previously studied for Binary Phase Shift Keying-(BPSK- and Sine Binary Offset Carrier- (SinBOC- modulated signals is also analyzed in closed loop model with the new Composite

  9. CANDU in-reactor quantitative visual-based inspection techniques

    Science.gov (United States)

    Rochefort, P. A.

    2009-02-01

    This paper describes two separate visual-based inspection procedures used at CANDU nuclear power generating stations. The techniques are quantitative in nature and are delivered and operated in highly radioactive environments with access that is restrictive, and in one case is submerged. Visual-based inspections at stations are typically qualitative in nature. For example a video system will be used to search for a missing component, inspect for a broken fixture, or locate areas of excessive corrosion in a pipe. In contrast, the methods described here are used to measure characteristic component dimensions that in one case ensure ongoing safe operation of the reactor and in the other support reactor refurbishment. CANDU reactors are Pressurized Heavy Water Reactors (PHWR). The reactor vessel is a horizontal cylindrical low-pressure calandria tank approximately 6 m in diameter and length, containing heavy water as a neutron moderator. Inside the calandria, 380 horizontal fuel channels (FC) are supported at each end by integral end-shields. Each FC holds 12 fuel bundles. The heavy water primary heat transport water flows through the FC pressure tube, removing the heat from the fuel bundles and delivering it to the steam generator. The general design of the reactor governs both the type of measurements that are required and the methods to perform the measurements. The first inspection procedure is a method to remotely measure the gap between FC and other in-core horizontal components. The technique involves delivering vertically a module with a high-radiation-resistant camera and lighting into the core of a shutdown but fuelled reactor. The measurement is done using a line-of-sight technique between the components. Compensation for image perspective and viewing elevation to the measurement is required. The second inspection procedure measures flaws within the reactor's end shield FC calandria tube rolled joint area. The FC calandria tube (the outer shell of the FC) is

  10. Electrical-Based Diagnostic Techniques for Assessing Insulation Condition in Aged Transformers

    Directory of Open Access Journals (Sweden)

    Issouf Fofana

    2016-08-01

    Full Text Available The condition of the internal cellulosic paper and oil insulation are of concern for the performance of power transformers. Over the years, a number of methods have been developed to diagnose and monitor the degradation/aging of the transformer internal insulation system. Some of this degradation/aging can be assessed from electrical responses. Currently there are a variety of electrical-based diagnostic techniques available for insulation condition monitoring of power transformers. In most cases, the electrical signals being monitored are due to mechanical or electric changes caused by physical changes in resistivity, inductance or capacitance, moisture, contamination or aging by-products in the insulation. This paper presents a description of commonly used and modern electrical-based diagnostic techniques along with their interpretation schemes.

  11. Automated Software Testing Using Metahurestic Technique Based on An Ant Colony Optimization

    CERN Document Server

    Srivastava, Praveen Ranjan

    2011-01-01

    Software testing is an important and valuable part of the software development life cycle. Due to time, cost and other circumstances, exhaustive testing is not feasible that's why there is a need to automate the software testing process. Testing effectiveness can be achieved by the State Transition Testing (STT) which is commonly used in real time, embedded and web-based type of software systems. Aim of the current paper is to present an algorithm by applying an ant colony optimization technique, for generation of optimal and minimal test sequences for behavior specification of software. Present paper approach generates test sequence in order to obtain the complete software coverage. This paper also discusses the comparison between two metaheuristic techniques (Genetic Algorithm and Ant Colony optimization) for transition based testing

  12. Quantification of Virus Particles Using Nanopore-Based Resistive-Pulse Sensing Techniques

    Directory of Open Access Journals (Sweden)

    Lu Yang

    2016-09-01

    Full Text Available Viruses have drawn much attention in recent years due to increased recognition of their important roles in virology, immunology, clinical diagnosis, and therapy. Because the biological and physical properties of viruses significantly impact their applications, quantitative detection of individual virus particles has become a critical issue. However, due to various inherent limitations of conventional enumeration techniques such as infectious titer assays, immunological assays, and electron microscopic observation, this issue remains challenging. Thanks to significant advances in nanotechnology, nanostructure-based electrical sensors have emerged as promising platforms for real-time, sensitive detection of numerous bioanalytes. In this paper, we review recent progress in nanopore-based electrical sensing, with particular emphasis on the application of this technique to the quantification of virus particles. Our aim is to provide insights into this novel nanosensor technology, and highlight its ability to enhance current understanding of a variety of viruses.

  13. Single-current-sensor-based active front-end-converter-fed four quadrants induction motor drive

    Indian Academy of Sciences (India)

    JOSEPH KIRAN BANDA; AMIT KUMAR JAIN

    2017-08-01

    Induction motor (IM) is a workhorse of the industry, whose dynamics can be modified close to that of a separately excited DC machine by field-oriented control technique, which is commonly known as vector control of induction machine. This paper presents a complete performance of the field-oriented control of IM drive in all four quadrants with a single-current-sensor-based active front end converter whose work is to regulate DC link voltage, draw pure sinusoidal currents at unity power factor and to facilitate bi-directional power flow between the grid and the drive. The entire system is completely modelled in MATLAB/SIMULINK and the results are discussed in detail. The vector control analogy of the back to back converters is highlighted along with the experimental results of field-oriented control of induction machine using a dsPIC30F6010A digital signal controller.

  14. Molecular and cellular approaches for the detection of protein-protein interactions: latest techniques and current limitations.

    Science.gov (United States)

    Lalonde, Sylvie; Ehrhardt, David W; Loqué, Dominique; Chen, Jin; Rhee, Seung Y; Frommer, Wolf B

    2008-02-01

    Homotypic and heterotypic protein interactions are crucial for all levels of cellular function, including architecture, regulation, metabolism, and signaling. Therefore, protein interaction maps represent essential components of post-genomic toolkits needed for understanding biological processes at a systems level. Over the past decade, a wide variety of methods have been developed to detect, analyze, and quantify protein interactions, including surface plasmon resonance spectroscopy, NMR, yeast two-hybrid screens, peptide tagging combined with mass spectrometry and fluorescence-based technologies. Fluorescence techniques range from co-localization of tags, which may be limited by the optical resolution of the microscope, to fluorescence resonance energy transfer-based methods that have molecular resolution and can also report on the dynamics and localization of the interactions within a cell. Proteins interact via highly evolved complementary surfaces with affinities that can vary over many orders of magnitude. Some of the techniques described in this review, such as surface plasmon resonance, provide detailed information on physical properties of these interactions, while others, such as two-hybrid techniques and mass spectrometry, are amenable to high-throughput analysis using robotics. In addition to providing an overview of these methods, this review emphasizes techniques that can be applied to determine interactions involving membrane proteins, including the split ubiquitin system and fluorescence-based technologies for characterizing hits obtained with high-throughput approaches. Mass spectrometry-based methods are covered by a review by Miernyk and Thelen (2008; this issue, pp. 597-609). In addition, we discuss the use of interaction data to construct interaction networks and as the basis for the exciting possibility of using to predict interaction surfaces.

  15. Kernel-based machine learning techniques for infrasound signal classification

    Science.gov (United States)

    Tuma, Matthias; Igel, Christian; Mialle, Pierrick

    2014-05-01

    Infrasound monitoring is one of four remote sensing technologies continuously employed by the CTBTO Preparatory Commission. The CTBTO's infrasound network is designed to monitor the Earth for potential evidence of atmospheric or shallow underground nuclear explosions. Upon completion, it will comprise 60 infrasound array stations distributed around the globe, of which 47 were certified in January 2014. Three stages can be identified in CTBTO infrasound data processing: automated processing at the level of single array stations, automated processing at the level of the overall global network, and interactive review by human analysts. At station level, the cross correlation-based PMCC algorithm is used for initial detection of coherent wavefronts. It produces estimates for trace velocity and azimuth of incoming wavefronts, as well as other descriptive features characterizing a signal. Detected arrivals are then categorized into potentially treaty-relevant versus noise-type signals by a rule-based expert system. This corresponds to a binary classification task at the level of station processing. In addition, incoming signals may be grouped according to their travel path in the atmosphere. The present work investigates automatic classification of infrasound arrivals by kernel-based pattern recognition methods. It aims to explore the potential of state-of-the-art machine learning methods vis-a-vis the current rule-based and task-tailored expert system. To this purpose, we first address the compilation of a representative, labeled reference benchmark dataset as a prerequisite for both classifier training and evaluation. Data representation is based on features extracted by the CTBTO's PMCC algorithm. As classifiers, we employ support vector machines (SVMs) in a supervised learning setting. Different SVM kernel functions are used and adapted through different hyperparameter optimization routines. The resulting performance is compared to several baseline classifiers. All

  16. Parameter tuning of PVD process based on artificial intelligence technique

    Science.gov (United States)

    Norlina, M. S.; Diyana, M. S. Nor; Mazidah, P.; Rusop, M.

    2016-07-01

    In this study, an artificial intelligence technique is proposed to be implemented in the parameter tuning of a PVD process. Due to its previous adaptation in similar optimization problems, genetic algorithm (GA) is selected to optimize the parameter tuning of the RF magnetron sputtering process. The most optimized parameter combination obtained from GA's optimization result is expected to produce the desirable zinc oxide (ZnO) thin film from the sputtering process. The parameters involved in this study were RF power, deposition time and substrate temperature. The algorithm was tested to optimize the 25 datasets of parameter combinations. The results from the computational experiment were then compared with the actual result from the laboratory experiment. Based on the comparison, GA had shown that the algorithm was reliable to optimize the parameter combination before the parameter tuning could be done to the RF magnetron sputtering machine. In order to verify the result of GA, the algorithm was also been compared to other well known optimization algorithms, which were, particle swarm optimization (PSO) and gravitational search algorithm (GSA). The results had shown that GA was reliable in solving this RF magnetron sputtering process parameter tuning problem. GA had shown better accuracy in the optimization based on the fitness evaluation.

  17. The effects of processing techniques on magnesium-based composite

    Science.gov (United States)

    Rodzi, Siti Nur Hazwani Mohamad; Zuhailawati, Hussain

    2016-12-01

    The aim of this study is to investigate the effect of processing techniques on the densification, hardness and compressive strength of Mg alloy and Mg-based composite for biomaterial application. The control sample (pure Mg) and Mg-based composite (Mg-Zn/HAp) were fabricated through mechanical alloying process using high energy planetary mill, whilst another Mg-Zn/HAp composite was fabricated through double step processing (the matrix Mg-Zn alloy was fabricated by planetary mill, subsequently HAp was dispersed by roll mill). As-milled powder was then consolidated by cold press into 10 mm diameter pellet under 400 MPa compaction pressure before being sintered at 300 °C for 1 hour under the flow of argon. The densification of the sintered pellets were then determined by Archimedes principle. Mechanical properties of the sintered pellets were characterized by microhardness and compression test. The results show that the density of the pellets was significantly increased by addition of HAp, but the most optimum density was observed when the sample was fabricated through double step processing (1.8046 g/cm3). Slight increment in hardness and ultimate compressive strength were observed for Mg-Zn/HAp composite that was fabricated through double step processing (58.09 HV, 132.19 MPa), as compared to Mg-Zn/HAp produced through single step processing (47.18 HV, 122.49 MPa).

  18. Electron tomography based on a total variation minimization reconstruction technique

    Energy Technology Data Exchange (ETDEWEB)

    Goris, B., E-mail: bart.goris@ua.ac.be [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Van den Broek, W. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Batenburg, K.J. [Centrum Wiskunde and Informatica, Science Park 123, NL-1098XG Amsterdam (Netherlands); Vision Lab, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Heidari Mezerji, H.; Bals, S. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2012-02-15

    The 3D reconstruction of a tilt series for electron tomography is mostly carried out using the weighted backprojection (WBP) algorithm or using one of the iterative algorithms such as the simultaneous iterative reconstruction technique (SIRT). However, it is known that these reconstruction algorithms cannot compensate for the missing wedge. Here, we apply a new reconstruction algorithm for electron tomography, which is based on compressive sensing. This is a field in image processing specialized in finding a sparse solution or a solution with a sparse gradient to a set of ill-posed linear equations. Therefore, it can be applied to electron tomography where the reconstructed objects often have a sparse gradient at the nanoscale. Using a combination of different simulated and experimental datasets, it is shown that missing wedge artefacts are reduced in the final reconstruction. Moreover, it seems that the reconstructed datasets have a higher fidelity and are easier to segment in comparison to reconstructions obtained by more conventional iterative algorithms. -- Highlights: Black-Right-Pointing-Pointer A reconstruction algorithm for electron tomography is investigated based on total variation minimization. Black-Right-Pointing-Pointer Missing wedge artefacts are reduced by this algorithm. Black-Right-Pointing-Pointer The reconstruction is easier to segment. Black-Right-Pointing-Pointer More reliable quantitative information can be obtained.

  19. Damage detection technique by measuring laser-based mechanical impedance

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeonseok; Sohn, Hoon [Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (Daehak-ro 291, Yuseong-gu, Daejeon 305-701) (Korea, Republic of)

    2014-02-18

    This study proposes a method for measurement of mechanical impedance using noncontact laser ultrasound. The measurement of mechanical impedance has been of great interest in nondestructive testing (NDT) or structural health monitoring (SHM) since mechanical impedance is sensitive even to small-sized structural defects. Conventional impedance measurements, however, have been based on electromechanical impedance (EMI) using contact-type piezoelectric transducers, which show deteriorated performances induced by the effects of a) Curie temperature limitations, b) electromagnetic interference (EMI), c) bonding layers and etc. This study aims to tackle the limitations of conventional EMI measurement by utilizing laser-based mechanical impedance (LMI) measurement. The LMI response, which is equivalent to a steady-state ultrasound response, is generated by shooting the pulse laser beam to the target structure, and is acquired by measuring the out-of-plane velocity using a laser vibrometer. The formation of the LMI response is observed through the thermo-mechanical finite element analysis. The feasibility of applying the LMI technique for damage detection is experimentally verified using a pipe specimen under high temperature environment.

  20. Acellular dermal matrix based nipple reconstruction: A modified technique

    Directory of Open Access Journals (Sweden)

    Raghavan Vidya

    2017-09-01

    Full Text Available Nipple areolar reconstruction (NAR has evolved with the advancement in breast reconstruction and can improve self-esteem and, consequently, patient satisfaction. Although a variety of reconstruction techniques have been described in the literature varying from nipple sharing, local flaps to alloplastic and allograft augmentation, over time, loss of nipple projection remains a major problem. Acellular dermal matrices (ADM have revolutionised breast reconstruction more recently. We discuss the use of ADM to act as a base plate and strut to give support to the base and offer nipple bulk and projection in a primary procedure of NAR with a local clover shaped dermal flap in 5 breasts (4 patients. We used 5-point Likert scales (1 = highly unsatisfied, 5 = highly satisfied to assess patient satisfaction. Median age was 46 years (range: 38–55 years. Nipple projection of 8 mm, 7 mm, and 7 mms were achieved in the unilateral cases and 6 mm in the bilateral case over a median 18 month period. All patients reported at least a 4 on the Likert scale. We had no post-operative complications. It seems that nipple areolar reconstruction [NAR] using ADM can achieve nipple projection which is considered aesthetically pleasing for patients.

  1. Introducing Risk Management Techniques Within Project Based Software Engineering Courses

    Science.gov (United States)

    Port, Daniel; Boehm, Barry

    2002-03-01

    In 1996, USC switched its core two-semester software engineering course from a hypothetical-project, homework-and-exam course based on the Bloom taxonomy of educational objectives (knowledge, comprehension, application, analysis, synthesis, and evaluation). The revised course is a real-client team-project course based on the CRESST model of learning objectives (content understanding, problem solving, collaboration, communication, and self-regulation). We used the CRESST cognitive demands analysis to determine the necessary student skills required for software risk management and the other major project activities, and have been refining the approach over the last 5 years of experience, including revised versions for one-semester undergraduate and graduate project course at Columbia. This paper summarizes our experiences in evolving the risk management aspects of the project course. These have helped us mature more general techniques such as risk-driven specifications, domain-specific simplifier and complicator lists, and the schedule as an independent variable (SAIV) process model. The largely positive results in terms of review of pass / fail rates, client evaluations, product adoption rates, and hiring manager feedback are summarized as well.

  2. Comparison of three joint simulator wear debris isolation techniques: acid digestion, base digestion, and enzyme cleavage.

    Science.gov (United States)

    Niedzwiecki, S; Klapperich, C; Short, J; Jani, S; Ries, M; Pruitt, L

    2001-08-01

    Quantification of ultrahigh molecular weight polyethylene (UHMWPE) wear debris remains a challenging task in orthopedic device analysis. Currently, the weight loss method is the only accepted practice for quantifying the amount of wear generated from a PE component. This technique utilizes loaded soak controls and weight differences to account for polymeric material lost through wear mechanisms. This method enables the determination of the amount of wear in the orthopedic device, but it provides no information about debris particulate size distribution. In order to shed light on wear mechanisms, information about the wear debris and its size distribution is necessary. To date, particulate isolation has been performed using the base digestion technique. The method uses a strong base, ultracentrifugation, and filtration to digest serum constituents and to isolate PE debris from sera. It should be noted that particulate isolation methods provide valuable information about particulate size distribution and may elucidate the mechanisms of wear associated with polymeric orthopedic implants; however, these techniques do not yet provide a direct measure of the amount of wear. The aim of this study is to present alternative approaches to wear particle isolation for analysis of polymer wear in total joint replacements without recourse to ultracentrifugation. Three polymer wear debris isolation techniques (the base method, an acid treatment, and an enzymatic digestion technique) are compared for effectiveness in simulator studies. A requirement of each technique is that the wear particulate must be completely devoid of serum proteins in order to effectively image and count these particles. In all methods the isolation is performed through filtration and chemical treatment. Subsequently, the isolated polymer particles are imaged using scanning electron microscopy and quantified with digital image analysis. The results from this study clearly show that isolation can be

  3. Ocean current measurement techniques

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.

    stream_size 3 stream_content_type text/plain stream_name Trg_Calculat_Water_Depth_Chart_Datum_1991_6.pdf.txt stream_source_info Trg_Calculat_Water_Depth_Chart_Datum_1991_6.pdf.txt Content-Encoding ISO-8859-1 Content-Type text...

  4. Magnetoimpedance effect in current annealed Co-based amorphous wires

    Science.gov (United States)

    Ghanaatshoar, M.; Tehranchi, M. M.; Mohseni, S. M.; Parhizkari, M.; Roozmeh, S. E.; Jazayeri Gharehbagh, A.

    2006-09-01

    Current-annealing of Co68.15Fe4.35Si12.5B15 amorphous wires has been studied at various vacuum orders. Structure-sensitive properties such as the electrical resistance during Joule heating treatment have been monitored to investigate the structural changes. Different driving currents have been flowed through the samples at different vacuums between 6×10-2 and 6×10-5 mbar. Regarding the giant magnetoimpedance (GMI) effect, annealing at different vacuums but with the same current can lead to various responses.

  5. A Novel Modulation Function-Based Control of Modular Multilevel Converters for High Voltage Direct Current Transmission Systems

    Directory of Open Access Journals (Sweden)

    Majid Mehrasa

    2016-10-01

    Full Text Available In this paper, a novel modulation function-based method including analyses of the modulation index and phase is proposed for operation of modular multilevel converters (MMCs in high voltage direct current (HVDC transmission systems. The proposed modulation function-based control technique is developed based on thorough and precise analyses of all MMC voltages and currents in the a-b-c reference frame in which the alternating current (AC-side voltage is the first target to be obtained. Using the AC-side voltage, the combination of the MMC upper and lower arm voltages is achieved as the main structure of the proposed modulation function. The main contribution of this paper is to obtain two very simple new modulation functions to control MMC performance in different operating conditions. The features of the modulation function-based control technique are as follows: (1 this control technique is very simple and can be easily achieved in a-b-c reference frame without the need of using Park transformation; and (2 in addition, the inherent properties of the MMC model are considered in the proposed control technique. Considering these properties leads to constructing a control technique that is robust against MMC parameters changes and also is a very good tracking method for the components of MMC input currents. These features lead to improving the operation of MMC significantly, which can act as a rectifier in the HVDC structure. The simulation studies are conducted through MATLAB/SIMULINK software, and the results obtained verify the effectiveness of the proposed modulation function-based control technique.

  6. Validation techniques of agent based modelling for geospatial simulations

    Science.gov (United States)

    Darvishi, M.; Ahmadi, G.

    2014-10-01

    One of the most interesting aspects of modelling and simulation study is to describe the real world phenomena that have specific properties; especially those that are in large scales and have dynamic and complex behaviours. Studying these phenomena in the laboratory is costly and in most cases it is impossible. Therefore, Miniaturization of world phenomena in the framework of a model in order to simulate the real phenomena is a reasonable and scientific approach to understand the world. Agent-based modelling and simulation (ABMS) is a new modelling method comprising of multiple interacting agent. They have been used in the different areas; for instance, geographic information system (GIS), biology, economics, social science and computer science. The emergence of ABM toolkits in GIS software libraries (e.g. ESRI's ArcGIS, OpenMap, GeoTools, etc) for geospatial modelling is an indication of the growing interest of users to use of special capabilities of ABMS. Since ABMS is inherently similar to human cognition, therefore it could be built easily and applicable to wide range applications than a traditional simulation. But a key challenge about ABMS is difficulty in their validation and verification. Because of frequent emergence patterns, strong dynamics in the system and the complex nature of ABMS, it is hard to validate and verify ABMS by conventional validation methods. Therefore, attempt to find appropriate validation techniques for ABM seems to be necessary. In this paper, after reviewing on Principles and Concepts of ABM for and its applications, the validation techniques and challenges of ABM validation are discussed.

  7. Validation techniques of agent based modelling for geospatial simulations

    Directory of Open Access Journals (Sweden)

    M. Darvishi

    2014-10-01

    Full Text Available One of the most interesting aspects of modelling and simulation study is to describe the real world phenomena that have specific properties; especially those that are in large scales and have dynamic and complex behaviours. Studying these phenomena in the laboratory is costly and in most cases it is impossible. Therefore, Miniaturization of world phenomena in the framework of a model in order to simulate the real phenomena is a reasonable and scientific approach to understand the world. Agent-based modelling and simulation (ABMS is a new modelling method comprising of multiple interacting agent. They have been used in the different areas; for instance, geographic information system (GIS, biology, economics, social science and computer science. The emergence of ABM toolkits in GIS software libraries (e.g. ESRI’s ArcGIS, OpenMap, GeoTools, etc for geospatial modelling is an indication of the growing interest of users to use of special capabilities of ABMS. Since ABMS is inherently similar to human cognition, therefore it could be built easily and applicable to wide range applications than a traditional simulation. But a key challenge about ABMS is difficulty in their validation and verification. Because of frequent emergence patterns, strong dynamics in the system and the complex nature of ABMS, it is hard to validate and verify ABMS by conventional validation methods. Therefore, attempt to find appropriate validation techniques for ABM seems to be necessary. In this paper, after reviewing on Principles and Concepts of ABM for and its applications, the validation techniques and challenges of ABM validation are discussed.

  8. Current concepts on posterior meniscal root lesion: A treatment algorithm based on the currently available evidence

    Directory of Open Access Journals (Sweden)

    Guan-Yang Song

    2014-07-01

    Full Text Available Meniscal root lesion is defined as an avulsion of the tibial insertion of the meniscus or a radial tear close to the meniscal insertion, which is commonly observed at the posterior region in the clinical practice. Although a number of biomechanical and clinical studies have shown the importance of the integrity of the posterior meniscal roots, the appropriate treatment is still controversial. The purposes of this review are to develop a current understanding of how the posterior meniscal root functions and to review the available treatment options for posterior meniscal root lesion.

  9. Ground-based intercomparison of two isoprene measurement techniques

    Directory of Open Access Journals (Sweden)

    E. Leibrock

    2003-01-01

    Full Text Available An informal intercomparison of two isoprene (C5H8 measurement techniques was carried out during Fall of 1998 at a field site located approximately 3 km west of Boulder, Colorado, USA. A new chemical ionization mass spectrometric technique (CIMS was compared to a well-established gas chromatographic technique (GC. The CIMS technique utilized benzene cation chemistry to ionize isoprene. The isoprene levels measured by the CIMS were often larger than those obtained with the GC. The results indicate that the CIMS technique suffered from an anthropogenic interference associated with air masses from the Denver, CO metropolitan area as well as an additional interference occurring in clean conditions. However, the CIMS technique is also demonstrated to be sensitive and fast. Especially after introduction of a tandem mass spectrometric technique, it is therefore a candidate for isoprene measurements in remote environments near isoprene sources.

  10. The Namibian fishing industry is based on the Benguela Current ...

    African Journals Online (AJOL)

    denise

    Current, one of four highly productive eastern boundary ... kob Argyrosomus inodorus and West Coast steenbras Lithognathus aureti, ..... value the tuna fishery, the deep-sea red crab fishery, the .... Ph.D. thesis, University of Port Elizabeth:.

  11. Current Trends in Computer-Based Education in Medicine

    Science.gov (United States)

    Farquhar, Barbara B.; Votaw, Robert G.

    1978-01-01

    Important current trends in the use of computer technology to enhance medical education are reported in the areas of simulation and assessment of clinical competence, curriculum integration, financial support, and means of exchanging views and scientific information. (RAO)

  12. Nanosatellites in LEO and beyond: Advanced Radiation protection techniques for COTS-based spacecraft

    Science.gov (United States)

    Selčan, David; Kirbiš, Gregor; Kramberger, Iztok

    2017-02-01

    This paper presents an approach for implementing radiation protection FDIR (Fault Detection, Isolation and Recovery) techniques designed especially for nanosatellites, capable of ensuring reliable operation in harsh orbits using COTS (Commercial off the Shelf) components. The radiation environment, as encountered by nanosatellites utilizing Flash-based FPGAs in orbits higher than Low Earth Orbit, is analyzed, primarily focusing on SEE (Single Event Effects). In order to assure reliable operation, the FDIR policy is split into two levels: the Low Level FDIR which ensures that no permanent damage occurs to the satellite's electronics, which then allows the use of a High Level FDIR tasked with maintaining high availability. A hierarchical approach, consisting of three types of current limiters in combination with watchdog timers and fault tolerant logic implemented inside a flash-based FPGA is proposed for the Low Level FDIR. The impacts of various radiation-induced faults are analyzed with respect to how the FDIR techniques mitigate them. The proposed current limiters and watchdog timers have been implemented and evaluated for suitability of use with the hierarchical FDIR policy. In order to decrease the impacts on the size and weight footprints, the current limiters were implemented as stacked 3D modules.

  13. Application of adjoint assimilation technique in simulating tides and tidal currents of the Bohai Sea, the Yellow Sea and the East China Sea

    Institute of Scientific and Technical Information of China (English)

    Cheng Yongcun; Lu Xianqing; Liu Yuguang; Xu Qing

    2007-01-01

    Considering the interaction of different tidal waves, an adjoint numerical model is developed to simulate M2, S2, K1 and O1 tidal waves in the Bohai Sea, the Yellow Sea and the East China Sea(B-Y-E) simultaneously. Compared with previous researches, by using the adjoint assimilation technique to inverse open boundary conditions and bottom friction coefficients based on altimetric data from TOPEX/Poseidon (T/P)and tidal gauges data, the precision of the numerical simulation is significantly improved. Selecting 14 days of simulated results after t11e initial warming run to conduct harmonic analysis, the results can show the characteristics of M2, S2, K1 and O1 tidal wave systems perfectly in B-Y-E. Compared with 9 current stations, the calculated harmonic constants of tidal currents for M2 and K1 are in good agreement With the observed ones.

  14. A Review of Financial Accounting Fraud Detection based on Data Mining Techniques

    Science.gov (United States)

    Sharma, Anuj; Kumar Panigrahi, Prabin

    2012-02-01

    With an upsurge in financial accounting fraud in the current economic scenario experienced, financial accounting fraud detection (FAFD) has become an emerging topic of great importance for academic, research and industries. The failure of internal auditing system of the organization in identifying the accounting frauds has lead to use of specialized procedures to detect financial accounting fraud, collective known as forensic accounting. Data mining techniques are providing great aid in financial accounting fraud detection, since dealing with the large data volumes and complexities of financial data are big challenges for forensic accounting. This paper presents a comprehensive review of the literature on the application of data mining techniques for the detection of financial accounting fraud and proposes a framework for data mining techniques based accounting fraud detection. The systematic and comprehensive literature review of the data mining techniques applicable to financial accounting fraud detection may provide a foundation to future research in this field. The findings of this review show that data mining techniques like logistic models, neural networks, Bayesian belief network, and decision trees have been applied most extensively to provide primary solutions to the problems inherent in the detection and classification of fraudulent data.

  15. Using Metadata Analysis and Base Analysis Techniques in Data Qualities Framework for Data Warehouses

    Directory of Open Access Journals (Sweden)

    Azwa A. Aziz

    2011-01-01

    Full Text Available Information provided by any applications systems in organization is vital in order to obtain a decision. Due to this factor, the quality of data provided by Data Warehouse (DW is really important for organization to produce the best solution for their company to move forwards. DW is complex systems that have to deliver highly-aggregated, high quality data from heterogeneous sources to decision makers. It involves a lot of integration of sources system to support business operations. Problem statement: Many of DW projects are failed because of Data Quality (DQ problems. DQ issues become a major concern over decade. Approach: This study proposes a framework for implementing DQ in DW system architecture using Metadata Analysis Technique and Base Analysis Technique. Those techniques perform comparison between target values and current values gain from the systems. A prototype using PHP is develops to support Base Analysis Techniques. Then a sample schema from Oracle database is used to study differences between applying the framework or not. The prototype is demonstrated to the selected organizations to identify whether it will help to reduce DQ problems. Questionnaires have been given to respondents. Results: The result show user interested in applying DQ processes in their organizations. Conclusion/Recommendation: The implementation of the framework suggested in real situation need to be conducted to obtain more accurate result.

  16. Molecular-Based Optical Measurement Techniques for Transition and Turbulence in High-Speed Flow

    Science.gov (United States)

    Bathel, Brett F.; Danehy, Paul M.; Cutler, Andrew D.

    2013-01-01

    High-speed laminar-to-turbulent transition and turbulence affect the control of flight vehicles, the heat transfer rate to a flight vehicle's surface, the material selected to protect such vehicles from high heating loads, the ultimate weight of a flight vehicle due to the presence of thermal protection systems, the efficiency of fuel-air mixing processes in high-speed combustion applications, etc. Gaining a fundamental understanding of the physical mechanisms involved in the transition process will lead to the development of predictive capabilities that can identify transition location and its impact on parameters like surface heating. Currently, there is no general theory that can completely describe the transition-to-turbulence process. However, transition research has led to the identification of the predominant pathways by which this process occurs. For a truly physics-based model of transition to be developed, the individual stages in the paths leading to the onset of fully turbulent flow must be well understood. This requires that each pathway be computationally modeled and experimentally characterized and validated. This may also lead to the discovery of new physical pathways. This document is intended to describe molecular based measurement techniques that have been developed, addressing the needs of the high-speed transition-to-turbulence and high-speed turbulence research fields. In particular, we focus on techniques that have either been used to study high speed transition and turbulence or techniques that show promise for studying these flows. This review is not exhaustive. In addition to the probe-based techniques described in the previous paragraph, several other classes of measurement techniques that are, or could be, used to study high speed transition and turbulence are excluded from this manuscript. For example, surface measurement techniques such as pressure and temperature paint, phosphor thermography, skin friction measurements and

  17. Signal Processing Techniques for Silicon Drift Detector Based X-Ray Spectrometer for Planatary Instruments

    Science.gov (United States)

    Patel, A.; Shanmugam, M.; Ladiya, T.

    2016-10-01

    We are developing SDD based x-ray spectrometer using various pulse height analysis techniques. This study will help to identify the proper processing technique based on instrument specifications which can be used for future scientific missions.

  18. DSP and FPGA Based Bunch Current Signal Processing

    CERN Document Server

    Naylor, G A

    2001-01-01

    The current in electron storage rings used as synchrotron light sources must be measured to a very high precision in order to determine the stored beam lifetime. This is especially so in high-energy machines in which the lifetime may be very high. Parametric current transformers (PCT) have traditionally been used to measure the DC or average current in the machine, which offer a very high resolution. Unfortunately these do not allow the different components of a complex filling pattern to be measured separately. A hybrid filling mode delivered at the ESRF consists of one third of the ring filled with bunches with a single highly populated bunch in the middle of the two-thirds gap. The lifetime of these two components may be very different. Similarly the two components are injected separately and can be monitored separately using a fast current transformer (FCT) or an integrating current transformer (ICT). The signals from these devices can be analysed using high speed analogue to digital converters operating ...

  19. Polyethersulfone improves isothermal nucleic acid amplification compared to current paper-based diagnostics.

    Science.gov (United States)

    Linnes, J C; Rodriguez, N M; Liu, L; Klapperich, C M

    2016-04-01

    Devices based on rapid, paper-based, isothermal nucleic acid amplification techniques have recently emerged with the potential to fill a growing need for highly sensitive point-of-care diagnostics throughout the world. As this field develops, such devices will require optimized materials that promote amplification and sample preparation. Herein, we systematically investigated isothermal nucleic acid amplification in materials currently used in rapid diagnostics (cellulose paper, glass fiber, and nitrocellulose) and two additional porous membranes with upstream sample preparation capabilities (polyethersulfone and polycarbonate). We compared amplification efficiency from four separate DNA and RNA targets (Bordetella pertussis, Chlamydia trachomatis, Neisseria gonorrhoeae, and Influenza A H1N1) within these materials using two different isothermal amplification schemes, helicase dependent amplification (tHDA) and loop-mediated isothermal amplification (LAMP), and traditional PCR. We found that the current paper-based diagnostic membranes inhibited nucleic acid amplification when compared to membrane-free controls; however, polyethersulfone allowed for efficient amplification in both LAMP and tHDA reactions. Further, observing the performance of traditional PCR amplification within these membranes was not predicative of their effects on in situ LAMP and tHDA. Polyethersulfone is a new material for paper-based nucleic acid amplification, yet provides an optimal support for rapid molecular diagnostics for point-of-care applications.

  20. Structuring Task-based Interaction through Collaborative Learning Techniques (2)

    Institute of Scientific and Technical Information of China (English)

    William Littlewood

    2004-01-01

    @@ Techniques for collaborative learning In this section the focus will move from broad strategies to specific techniques (often also called "structures") through which the strategies can be realized. It gives a selection of techniques which have proved (in my own experience as well as that of others) particularly useful in pro-viding contexts for practice, exploration and /or interaction in the second language classroom.

  1. Research on technique of wavefront retrieval based on Foucault test

    Science.gov (United States)

    Yuan, Lvjun; Wu, Zhonghua

    2010-05-01

    During finely grinding the best fit sphere and initial stage of polishing, surface error of large aperture aspheric mirrors is too big to test using common interferometer. Foucault test is widely used in fabricating large aperture mirrors. However, the optical path is disturbed seriously by air turbulence, and changes of light and dark zones can not be identified, which often lowers people's judging ability and results in making mistake to diagnose surface error of the whole mirror. To solve the problem, the research presents wavefront retrieval based on Foucault test through digital image processing and quantitative calculation. Firstly, real Foucault image can be gained through collecting a variety of images by CCD, and then average these image to eliminate air turbulence. Secondly, gray values are converted into surface error values through principle derivation, mathematical modeling, and software programming. Thirdly, linear deviation brought by defocus should be removed by least-square method to get real surface error. At last, according to real surface error, plot wavefront map, gray contour map and corresponding pseudo color contour map. The experimental results indicates that the three-dimensional wavefront map and two-dimensional contour map are able to accurately and intuitively show surface error on the whole mirrors under test, and they are beneficial to grasp surface error as a whole. The technique can be used to guide the fabrication of large aperture and long focal mirrors during grinding and initial stage of polishing the aspheric surface, which improves fabricating efficiency and precision greatly.

  2. Formal Verification Techniques Based on Boolean Satisfiability Problem

    Institute of Scientific and Technical Information of China (English)

    Xiao-Wei Li; Guang-Hui Li; Ming Shao

    2005-01-01

    This paper exploits Boolean satisfiability problem in equivalence checking and model checking respectively. A combinational equivalence checking method based on incremental satisfiability is presented. This method chooses the can didate equivalent pairs with some new techniques, and uses incremental satisfiability algorithm to improve its performance. By substituting the internal equivalent pairs and converting the equivalence relations into conjunctive normal form (CNF) formulas, this approach can avoid the false negatives, and reduce the search space of SAT procedure. Experimental results on ISCAS'85 benchmark circuits show that, the presented approach is faster and more robust than those existed in literature.This paper also presents an algorithm for extracting of unsatisfiable core, which has an important application in abstraction and refinement for model checking to alleviate the state space explosion bottleneck. The error of approximate extraction is analyzed by means of simulation. An analysis reveals that an interesting phenomenon occurs, with the increasing density of the formula, the average error of the extraction is decreasing. An exact extraction approach for MU subformula, referred to as pre-assignment algorithm, is proposed. Both theoretical analysis and experimental results show that it is more efficient.

  3. A formal model for integrity protection based on DTE technique

    Institute of Scientific and Technical Information of China (English)

    JI Qingguang; QING Sihan; HE Yeping

    2006-01-01

    In order to provide integrity protection for the secure operating system to satisfy the structured protection class' requirements, a DTE technique based integrity protection formalization model is proposed after the implications and structures of the integrity policy have been analyzed in detail. This model consists of some basic rules for configuring DTE and a state transition model, which are used to instruct how the domains and types are set, and how security invariants obtained from initial configuration are maintained in the process of system transition respectively. In this model, ten invariants are introduced, especially, some new invariants dealing with information flow are proposed, and their relations with corresponding invariants described in literatures are also discussed.The thirteen transition rules with well-formed atomicity are presented in a well-operational manner. The basic security theorems correspond to these invariants and transition rules are proved. The rationalities for proposing the invariants are further annotated via analyzing the differences between this model and ones described in literatures. At last but not least, future works are prospected, especially, it is pointed out that it is possible to use this model to analyze SE-Linux security.

  4. Biofunctionalization of Si nanowires using a solution based technique

    Science.gov (United States)

    Williams, Elissa H.; Davydov, Albert V.; Oleshko, Vladimir P.; Lin, Nancy J.; Steffens, Kristen L.; Manocchi, Amy K.; Krylyuk, Sergiy; Rao, Mulpuri V.; Schreifels, John A.

    2012-10-01

    Here we present a solution based functionalization technique for streptavidin (SA) protein conjugation to silicon nanowires (Si NWs). Si NWs, with a diameter of 110 nm to 130 nm and a length of 5 μm to 10 μm, were functionalized with 3-aminopropyltriethoxysilane (APTES) followed by biotin for the selective attachment of SA. High-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM) showed that the Si NWs were conformally coated with 20 nm to 30 nm thick APTES, biotin, and SA layers upon functionalization. Successful attachment of each bio/organic layer was confirmed by X-ray photoelectron spectroscopy (XPS) and fluorescence microscopy. Fluorescence microscopy also demonstrated that there was an undesirable non-specific binding of the SA protein as well as a control protein, bovine serum albumin (BSA), to the APTES-coated Si NWs. However, inhibition of BSA binding and enhancement of SA binding were achieved following the biotinylation step. The biofunctionalized Si NWs show potential as label-free biosensing platforms for the specific and selective detection of biomolecules.

  5. Channel Based Adaptive Rate Control Technique for MANET

    Directory of Open Access Journals (Sweden)

    R. Bharathiraja

    2014-04-01

    Full Text Available In Mobile Ad hoc Networks (MANET, most of the existing works does not consider energy efficiency during selecting the appropriate route. Hence in MANET selecting the appropriate route and also maintaining energy efficiency is very important. Hence in order to overcome these issues, in this study we propose Channel Based Adaptive Rate Control technique for MANET. Here the most appropriate links is selected to transmit the node with efficient power consumption. The node broadcasts the information of its outgoing and incoming links in NSET instead of waiting for the feedback informattion from receiver. The number of packets transmitted in a channel access time is maximized by implementing the benefit ratio in rate selection algorithm. This study also introduces node cooperation, in node cooperation the node determines the feasibility of new rate setting determined by rate selection algorithm and it carries out new setting if it is feasible by following help, ack, reject and accept method. By simulation results we show that the proposed approach is power efficient and also increases the trasmission rate.

  6. Laser polymerization-based novel lift-off technique

    Energy Technology Data Exchange (ETDEWEB)

    Bhuian, B. [Tyndall National Institute, Lee Maltings, Prospect Row, Cork (Ireland); Department of Microelectronic Engineering, University College Cork, Cork (Ireland); Winfield, R.J. [Tyndall National Institute, Lee Maltings, Prospect Row, Cork (Ireland)], E-mail: richard.winfield@tyndall.ie; Crean, G.M. [Tyndall National Institute, Lee Maltings, Prospect Row, Cork (Ireland); Department of Microelectronic Engineering, University College Cork, Cork (Ireland)

    2009-03-01

    The fabrication of microstructures by two-photon polymerization has been widely reported as a means of directly writing three-dimensional nanoscale structures. In the majority of cases a single point serial writing technique is used to form a polymer model. Single layer writing can also be used to fabricate two-dimensional patterns and we report an extension of this capability by using two-photon polymerization to form a template that can be used as a sacrificial layer for a novel lift-off process. A Ti:sapphire laser, with wavelength 795 nm, 80 MHz repetition rate, 100 fs pulse duration and an average power of 700 mW, was used to write 2D grid patterns with pitches of 0.8 and 1.0 {mu}m in a urethane acrylate resin that was spun on to a lift-off base layer. This was overcoated with gold and the grid lifted away to leave an array of gold islands. The optical transmission properties of the gold arrays were measured and found to be in agreement with a rigorous coupled-wave analysis simulation.

  7. Orientation of student entrepreneurial practices based on administrative techniques

    Directory of Open Access Journals (Sweden)

    Héctor Horacio Murcia Cabra

    2005-07-01

    Full Text Available As part of the second phase of the research project «Application of a creativity model to update the teaching of the administration in Colombian agricultural entrepreneurial systems» it was decided to re-enforce student planning and execution of the students of the Agricultural business Administration Faculty of La Salle University. Those finishing their studies were given special attention. The plan of action was initiated in the second semester of 2003. It was initially defined as a model of entrepreneurial strengthening based on a coherent methodology that included the most recent administration and management techniques. Later, the applicability of this model was tested in some organizations of the agricultural sector that had asked for support in their planning processes. Through an investigation-action process the methodology was redefined in order to arrive at a final model that could be used by faculty students and graduates. The results obtained were applied to the teaching of Entrepreneurial Laboratory of ninth semester students with the hope of improving administrative support to agricultural enterprises. Following this procedure more than 100 students and 200 agricultural producers have applied this procedure between June 2003 and July 2005. The methodology used and the results obtained are presented in this article.

  8. Image content authentication technique based on Laplacian Pyramid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper proposes a technique of image content authentication based on the Laplacian Pyramid to verify the authenticity of image content.First,the image is decomposed into Laplacian Pyramid before the transformation.Next,the smooth and detail properties of the original image are analyzed according to the Laplacian Pyramid,and the properties are classified and encoded to get the corresponding characteristic values.Then,the signature derived from the encrypted characteristic values is embedded in the original image as a watermark.After the reception,the characteristic values of the received image are compared with the watermark drawn out from the image.The algorithm automatically identifies whether the content is tampered by means of morphologic filtration.The information of tampered location is Presented at the same time.Experimental results show that the pro posed authentication algorithm can effectively detect the event and location when the original image content is tampered.Moreover,it can tolerate some distortions produced by compression,filtration and noise degradation.

  9. WORMHOLE ATTACK MITIGATION IN MANET: A CLUSTER BASED AVOIDANCE TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Subhashis Banerjee

    2014-01-01

    Full Text Available A Mobile Ad-Hoc Network (MANET is a self configuring, infrastructure less network of mobile devices connected by wireless links. Loopholes like wireless medium, lack of a fixed infrastructure, dynamic topology, rapid deployment practices, and the hostile environments in which they may be deployed, make MANET vulnerable to a wide range of security attacks and Wormhole attack is one of them. During this attack a malicious node captures packets from one location in the network, and tunnels them to another colluding malicious node at a distant point, which replays them locally. This paper presents a cluster based Wormhole attack avoidance technique. The concept of hierarchical clustering with a novel hierarchical 32- bit node addressing scheme is used for avoiding the attacking path during the route discovery phase of the DSR protocol, which is considered as the under lying routing protocol. Pinpointing the location of the wormhole nodes in the case of exposed attack is also given by using this method.

  10. Review of current interest and research in water hyacinth-based wastewater treatment

    Science.gov (United States)

    Markarian, R. K.; Balon, J. E.; Robinson, A. C.

    1977-01-01

    The status of activity in the user community for water hyacinth-based wastewater treatment was evaluated. The principal technique used was that of interviewing people who either (1) were known to be engaged in hyacinth research or development or (2) had made inquiry to NASA about hyacinth systems. About 40 non-research organizations and a similar number of research organizations were contacted. As a result of the interviews and a review of the relevant literature, it was concluded that hyacinth systems have the potential for providing a lower cost way for small cities to meet increasingly stringent effluent requirements. A limited amount of full-scale demonstration of hyacinth systems has been carried out during the past two years, but the yield of design data has been small. Several organizations are currently planning construction of experimental full-scale hyacinth-based wastewater treatment systems during 1977-1978.

  11. Silica-based UV-fibers for DUV applications: current status

    Science.gov (United States)

    Klein, K.-F.; Gonschior, C. P.; Beer, D.; Eckhardt, H.-S.; Belz, M.; Shannon, J.; Khalilov, V.; Klein, M.; Jakob, C.

    2013-05-01

    The current status of UV-damage in several different UV fibers due to defects in their synthetic high-OH silica core and cladding will be described. Further, steps to improve UV resistance and adequate measurement techniques based on a deuterium lamp setup are included. For the first time, the main parameters and their influences on UV induced losses are discussed in detail with an emphasis towards future standardization purposes. Applications based on two new UV light sources, a laser driven xenon plasma broad band source and a high pulse-power 355 nm Nd:YAG laser, are introduced. UV photo-darkening and -bleaching in UV fibers caused by this extremely powerful light source is demonstrated. Finally, first results on transmission of UV light in optical fibers at cryogenic temperatures are shown.

  12. A combined noise analysis and power supply current based testing of CMOS analog integrated circuits

    Science.gov (United States)

    Srivastava, Ashok; Pulendra, Vani K.; Yellampalli, Siva

    2005-05-01

    A technique integrating the noise analysis based testing and the conventional power supply current testing of CMOS analog integrated circuits is presented for bridging type faults due to manufacturing defects. The circuit under test (CUT) is a CMOS amplifier designed for operation at +/- 2.5 V and implemented in 1.5 μm CMOS process. The faults simulating possible manufacturing defects have been introduced using the fault injection transistors. The amplifier circuit is analyzed and simulated in SPICE for its performance with and without fault injections. The faults in the CUT are identified by observing the variation in the equivalent noise voltage at the output of CUT. In power supply current testing, the current (IPS) through the power supply voltage, VDD is measured under the application of an AC input stimulus. The effect of parametric variation is taken into consideration by determining the tolerance limit using the Monte-Carlo analysis. The fault is identified if the power supply current, IPS lies outside the deviation given by Monte-Carlo analysis. Simulation results are in close agreement with the corresponding experimental values.

  13. A Current Sensor Based on the Giant Magnetoresistance Effect: Design and Potential Smart Grid Applications

    Directory of Open Access Journals (Sweden)

    Shan X. Wang

    2012-11-01

    Full Text Available Advanced sensing and measurement techniques are key technologies to realize a smart grid. The giant magnetoresistance (GMR effect has revolutionized the fields of data storage and magnetic measurement. In this work, a design of a GMR current sensor based on a commercial analog GMR chip for applications in a smart grid is presented and discussed. Static, dynamic and thermal properties of the sensor were characterized. The characterizations showed that in the operation range from 0 to ±5 A, the sensor had a sensitivity of 28 mV·A−1, linearity of 99.97%, maximum deviation of 2.717%, frequency response of −1.5 dB at 10 kHz current measurement, and maximum change of the amplitude response of 0.0335%·°C−1 with thermal compensation. In the distributed real-time measurement and monitoring of a smart grid system, the GMR current sensor shows excellent performance and is cost effective, making it suitable for applications such as steady-state and transient-state monitoring. With the advantages of having a high sensitivity, high linearity, small volume, low cost, and simple structure, the GMR current sensor is promising for the measurement and monitoring of smart grids.

  14. A current sensor based on the giant magnetoresistance effect: design and potential smart grid applications.

    Science.gov (United States)

    Ouyang, Yong; He, Jinliang; Hu, Jun; Wang, Shan X

    2012-11-09

    Advanced sensing and measurement techniques are key technologies to realize a smart grid. The giant magnetoresistance (GMR) effect has revolutionized the fields of data storage and magnetic measurement. In this work, a design of a GMR current sensor based on a commercial analog GMR chip for applications in a smart grid is presented and discussed. Static, dynamic and thermal properties of the sensor were characterized. The characterizations showed that in the operation range from 0 to ±5 A, the sensor had a sensitivity of 28 mV·A(-1), linearity of 99.97%, maximum deviation of 2.717%, frequency response of −1.5 dB at 10 kHz current measurement, and maximum change of the amplitude response of 0.0335%·°C(-1) with thermal compensation. In the distributed real-time measurement and monitoring of a smart grid system, the GMR current sensor shows excellent performance and is cost effective, making it suitable for applications such as steady-state and transient-state monitoring. With the advantages of having a high sensitivity, high linearity, small volume, low cost, and simple structure, the GMR current sensor is promising for the measurement and monitoring of smart grids.

  15. Development of Evaluation Technique of GMAW Welding Quality Based on Statistical Analysis

    Institute of Scientific and Technical Information of China (English)

    FENG Shengqiang; TERASAKI Hidenri; KOMIZO Yuichi; HU Shengsun; CHEN Donggao; MA Zhihua

    2014-01-01

    Nondestructive techniques for appraising gas metal arc welding(GMAW) faults plays a very important role in on-line quality controllability and prediction of the GMAW process. On-line welding quality controllability and prediction have several disadvantages such as high cost, low efficiency, complication and greatly being affected by the environment. An enhanced, efficient evaluation technique for evaluating welding faults based on Mahalanobis distance(MD) and normal distribution is presented. In addition, a new piece of equipment, designated the weld quality tester(WQT), is developed based on the proposed evaluation technique. MD is superior to other multidimensional distances such as Euclidean distance because the covariance matrix used for calculating MD takes into account correlations in the data and scaling. The values of MD obtained from welding current and arc voltage are assumed to follow a normal distribution. The normal distribution has two parameters: the meanm and standard deviations of the data. In the proposed evaluation technique used by the WQT, values of MD located in the range from zero tom+3s are regarded as “good”. Two experiments which involve changing the flow of shielding gas and smearing paint on the surface of the substrate are conducted in order to verify the sensitivity of the proposed evaluation technique and the feasibility of using WQT. The experimental results demonstrate the usefulness of the WQT for evaluating welding quality. The proposed technique can be applied to implement the on-line welding quality controllability and prediction, which is of great importance to design some novel equipment for weld quality detection.

  16. Weighted graph based ordering techniques for preconditioned conjugate gradient methods

    Science.gov (United States)

    Clift, Simon S.; Tang, Wei-Pai

    1994-01-01

    We describe the basis of a matrix ordering heuristic for improving the incomplete factorization used in preconditioned conjugate gradient techniques applied to anisotropic PDE's. Several new matrix ordering techniques, derived from well-known algorithms in combinatorial graph theory, which attempt to implement this heuristic, are described. These ordering techniques are tested against a number of matrices arising from linear anisotropic PDE's, and compared with other matrix ordering techniques. A variation of RCM is shown to generally improve the quality of incomplete factorization preconditioners.

  17. Tidal current turbine based on hydraulic transmission system

    Institute of Scientific and Technical Information of China (English)

    Hong-wei LIU; Wei LI; Yong-gang LIN; Shun MA

    2011-01-01

    Tidal current turbines (TCTs) are newly developed electricity generating devices.Aiming at the stabilization of the power output of TCTs,this paper introduces the hydraulic transmission technologies into TCTs.The hydrodynamics of the turbine was analyzed at first and its power output characteristics were predicted.A hydraulic power transmission system and a hydraulic pitch-controlled system were designed.Then related simulations were conducted.Finally,a TCT prototype was manufactured and tested in the workshop.The test results have confirmed the correctness of the current design and availability of installation of the hydraulic system in TCTs.

  18. A Correlation Based Method for Discriminating Inrush Current from Short Circuit Current Using Wavelet Transform in Power Transformer Differential Protection

    Directory of Open Access Journals (Sweden)

    M. Rasoulpoor

    2013-09-01

    Full Text Available This paper presents a new approach for power transformer differential protection. The Wavelet Transform is applied to discriminate between inrush currents and internal fault currents in power transformers. Discrete wavelet transform decomposes the current signal into sub-bands that give more information about the properties of the signals in different frequency bands. Also, this transform is used to investigate the energy distribution of the signal on the different time and frequency scales. Recognition method is based on the correlation factors between energy percentage vectors of the Wavelet coefficients. Discrete Wavelet transform is used for decomposing the current signals to different frequency coefficients. After that, by constituting the energy percentage vectors of wavelet transform coefficients and calculating the correlation factors between these vectors, it is possible to form a recognition criterion to distinguish between inrush and internal fault current in the proposed method. The proposed algorithm is tested for several conditions by simulated inrush and internal fault currents. Simulation of current signals is performed using electromagnetic transient program PSCAD/EMTDC software that is a powerful program for the investigation of transient signals. Simulation results show that the proposed scheme accurately identifies inrush and fault currents in the distance of the power transformer protection in less than quarter of power frequency cycle. Also, beside the sensitivity and high reliability, the proposed method has low computation content and unlike the common methods does not require to determine the threshold for each new power system.

  19. Determination of High-Frequency Current Distribution Using EMTP-Based Transmission Line Models with Resulting Radiated Electromagnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Mork, B; Nelson, R; Kirkendall, B; Stenvig, N

    2009-11-30

    Application of BPL technologies to existing overhead high-voltage power lines would benefit greatly from improved simulation tools capable of predicting performance - such as the electromagnetic fields radiated from such lines. Existing EMTP-based frequency-dependent line models are attractive since their parameters are derived from physical design dimensions which are easily obtained. However, to calculate the radiated electromagnetic fields, detailed current distributions need to be determined. This paper presents a method of using EMTP line models to determine the current distribution on the lines, as well as a technique for using these current distributions to determine the radiated electromagnetic fields.

  20. Adoption of farm-based irrigation water-saving techniques in the Guanzhong Plain, China

    NARCIS (Netherlands)

    Tang, Jianjun; Folmer, Henk; Xue, Jianhong

    2016-01-01

    This article analyses adoption of farm-based irrigation water saving techniques, based on a cross-sectional data set of 357 farmers in the Guanzhong Plain, China. Approximately 83% of the farmers use at least one farm-based water-saving technique. However, the traditional, inefficient techniques bor

  1. The Current State of Silicone-Based Dielectric Elastomer Transducers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Daugaard, Anders Egede; Hvilsted, Søren

    2016-01-01

    driving voltages. In this review, the current state of sili- cone elastomers for DETs is summarised and critically discussed, including commercial elastomers, composites, polymer blends, grafted elastomers and complex network structures. For future developments in the field it is essential that all aspects...

  2. Hypersonic Vehicle Tracking Based on Improved Current Statistical Model

    Directory of Open Access Journals (Sweden)

    He Guangjun

    2013-11-01

    Full Text Available A new method of tracking the near space hypersonic vehicle is put forward. According to hypersonic vehicles’ characteristics, we improved current statistical model through online identification of the maneuvering frequency. A Monte Carlo simulation is used to analyze the performance of the method. The results show that the improved method exhibits very good tracking performance in comparison with the old method.

  3. Quadrature laser interferometer for in-line thickness measurement of glass panels using a current modulation technique.

    Science.gov (United States)

    Kim, Jong-Ahn; Kang, Chu-Shik; Eom, Tae Bong; Jin, Jonghan; Suh, Ho Suhng; Kim, Jae Wan

    2014-07-10

    A thickness measurement system is proposed for in-line inspection of thickness variation of flat glass panels. Multi-reflection on the surfaces of glass panel generates an interference signal whose phase is proportional to the thickness of the glass panel. For accurate and stable calculation of the phase value, we obtain quadrature interference signals using a current modulation technique. The proposed system can measure a thickness profile with high speed and nanometric resolution, and obtain higher accuracy through real-time nonlinear error compensation. The thickness profile, measured by a transmissive-type experimental setup, coincided with a comparative result obtained using a contact-type thickness measurement system within the range of ±40  nm. The standard deviations of the measured thickness profiles and their waviness components were less than 3 nm with a scanning speed of 300  mm/s.

  4. A novel input-parasitic compensation technique for a nanopore-based CMOS DNA detection sensor

    Science.gov (United States)

    Kim, Jungsuk

    2016-12-01

    This paper presents a novel input-parasitic compensation (IPC) technique for a nanopore-based complementary metal-oxide-semiconductor (CMOS) DNA detection sensor. A resistive-feedback transimpedance amplifier is typically adopted as the headstage of a DNA detection sensor to amplify the minute ionic currents generated from a nanopore and convert them to a readable voltage range for digitization. But, parasitic capacitances arising from the headstage input and the nanopore often cause headstage saturation during nanopore sensing, thereby resulting in significant DNA data loss. To compensate for the unwanted saturation, in this work, we propose an area-efficient and automated IPC technique, customized for a low-noise DNA detection sensor, fabricated using a 0.35- μm CMOS process; we demonstrated this prototype in a benchtop test using an α-hemolysin ( α-HL) protein nanopore.

  5. 3D-TV System with Depth-Image-Based Rendering Architectures, Techniques and Challenges

    CERN Document Server

    Zhao, Yin; Yu, Lu; Tanimoto, Masayuki

    2013-01-01

    Riding on the success of 3D cinema blockbusters and advances in stereoscopic display technology, 3D video applications have gathered momentum in recent years. 3D-TV System with Depth-Image-Based Rendering: Architectures, Techniques and Challenges surveys depth-image-based 3D-TV systems, which are expected to be put into applications in the near future. Depth-image-based rendering (DIBR) significantly enhances the 3D visual experience compared to stereoscopic systems currently in use. DIBR techniques make it possible to generate additional viewpoints using 3D warping techniques to adjust the perceived depth of stereoscopic videos and provide for auto-stereoscopic displays that do not require glasses for viewing the 3D image.   The material includes a technical review and literature survey of components and complete systems, solutions for technical issues, and implementation of prototypes. The book is organized into four sections: System Overview, Content Generation, Data Compression and Transmission, and 3D V...

  6. Evidence-based surgical techniques for caesarean section

    DEFF Research Database (Denmark)

    Aabakke, Anna J M; Secher, Niels Jørgen; Krebs, Lone

    2014-01-01

    Caesarean section (CS) is a common surgical procedure, and in Denmark 21% of deliveries is by CS. There is an increasing amount of scientific evidence to support the different surgical techniques used at CS. This article reviews the literature regarding CS techniques. There is still a lack...

  7. A Technique for Volumetric CSG Based on Morphology

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas; Christensen, Niels Jørgen

    2001-01-01

    In this paper, a new technique for volumetric CSG is presented. The technique requires the input volumes to correspond to solids which fulfill a voxelization suitability criterion. Assume the CSG operation is union. The volumetric union of two such volumes is defined in terms of the voxelization...

  8. A Lossless Data Hiding Technique based on AES-DWT

    Directory of Open Access Journals (Sweden)

    Gustavo Fernandaacute;ndez Torres2

    2012-09-01

    Full Text Available In this paper we propose a new data hiding technique. The new technique uses steganography and cryptography on images with a size of 256x256 pixels and an 8-bit grayscale format. There are design restrictions such as a fixed-size cover image, and reconstruction without error of the hidden image. The steganography technique uses a Haar-DWT (Discrete Wavelet Transform with hard thresholding and LSB (Less Significant Bit technique on the cover image. The algorithms used for compressing and ciphering the secret image are lossless JPG and AES, respectively. The proposed technique is used to generate a stego image which provides a double type of security that is robust against attacks. Results are reported for different thresholds levels in terms of PSNR.

  9. Non-invasive imaging techniques in assessing non-alcoholic fatty liver disease: a current status of available methods.

    Science.gov (United States)

    Lăpădat, A M; Jianu, I R; Ungureanu, B S; Florescu, L M; Gheonea, D I; Sovaila, S; Gheonea, I A

    2017-01-01

    Non-alcoholic fatty liver disease (NAFLD) is an ailment affecting and increasing a number of people worldwide diagnosed via non-invasive imaging techniques, at a time when a minimum harm caused by medical procedures is rightfully emphasized, more sought after, than ever before. Liver steatosis should not be taken lightly even if its evolution is largely benign as it has the potential to develop into non-alcoholic steatohepatitis (NASH) or even more concerning, hepatic cirrhosis, and hepatocellular carcinoma (HCC). Traditionally, liver biopsy has been the standard for diagnosing this particular liver disease, but nowadays, a consistent number of imagistic methods are available for diagnosing hepatosteatosis and choosing the one appropriate to the clinical context is the key. Although different in sensitivity and specificity when it comes to determining the hepatic fat fraction (FF), these imaging techniques possessing a diverse availability, operating difficulty, cost, and reproducibility are invaluable to any modern physician. Ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), elastography, and spectroscopy will be discussed in order to lay out the advantages and disadvantages of their diagnostic potential and application. Although imagistics has given physicians a valuable insight into the means of managing NAFLD, the current methods are far from perfect, but given the time, they will surely be improved and the use of liver biopsy will be completely removed.

  10. Systematic infrared image quality improvement using deep learning based techniques

    Science.gov (United States)

    Zhang, Huaizhong; Casaseca-de-la-Higuera, Pablo; Luo, Chunbo; Wang, Qi; Kitchin, Matthew; Parmley, Andrew; Monge-Alvarez, Jesus

    2016-10-01

    Infrared thermography (IRT, or thermal video) uses thermographic cameras to detect and record radiation in the longwavelength infrared range of the electromagnetic spectrum. It allows sensing environments beyond the visual perception limitations, and thus has been widely used in many civilian and military applications. Even though current thermal cameras are able to provide high resolution and bit-depth images, there are significant challenges to be addressed in specific applications such as poor contrast, low target signature resolution, etc. This paper addresses quality improvement in IRT images for object recognition. A systematic approach based on image bias correction and deep learning is proposed to increase target signature resolution and optimise the baseline quality of inputs for object recognition. Our main objective is to maximise the useful information on the object to be detected even when the number of pixels on target is adversely small. The experimental results show that our approach can significantly improve target resolution and thus helps making object recognition more efficient in automatic target detection/recognition systems (ATD/R).

  11. M Current-Based Therapies for Nerve Agent Seizures

    Science.gov (United States)

    2013-07-01

    Cholinergic nerve agents cause neuronal hyper-excitability by inhibiting M/KCNQ2/3 potassium channels. 2) Cholinergic seizures can be blocked by drugs ...characterize the effects of M current enhancers on excitabtility and bursting of CA1 pyramidal neurons. Aim 3) To test anticonvulsant action of three M...blocked all EPSCs. Miniature EPSCs (mEPSCs) were recorded by blocking action potentials with 1 μM TTX (Alomone labs, Jerusalem, Israel). All drugs were

  12. SPAM CLASSIFICATION BASED ON SUPERVISED LEARNING USING MACHINE LEARNING TECHNIQUES

    Directory of Open Access Journals (Sweden)

    T. Hamsapriya

    2011-12-01

    Full Text Available E-mail is one of the most popular and frequently used ways of communication due to its worldwide accessibility, relatively fast message transfer, and low sending cost. The flaws in the e-mail protocols and the increasing amount of electronic business and financial transactions directly contribute to the increase in e-mail-based threats. Email spam is one of the major problems of the today’s Internet, bringing financial damage to companies and annoying individual users. Spam emails are invading users without their consent and filling their mail boxes. They consume more network capacity as well as time in checking and deleting spam mails. The vast majority of Internet users are outspoken in their disdain for spam, although enough of them respond to commercial offers that spam remains a viable source of income to spammers. While most of the users want to do right think to avoid and get rid of spam, they need clear and simple guidelines on how to behave. In spite of all the measures taken to eliminate spam, they are not yet eradicated. Also when the counter measures are over sensitive, even legitimate emails will be eliminated. Among the approaches developed to stop spam, filtering is the one of the most important technique. Many researches in spam filtering have been centered on the more sophisticated classifier-related issues. In recent days, Machine learning for spam classification is an important research issue. The effectiveness of the proposed work is explores and identifies the use of different learning algorithms for classifying spam messages from e-mail. A comparative analysis among the algorithms has also been presented.

  13. Computation of currents induced by ELF electric fields in anisotropic human tissues using the Finite Integration Technique (FIT

    Directory of Open Access Journals (Sweden)

    V. C. Motrescu

    2005-01-01

    Full Text Available In the recent years, the task of estimating the currents induced within the human body by environmental electromagnetic fields has received increased attention from scientists around the world. While important progress was made in this direction, the unpredictable behaviour of living biological tissue made it difficult to quantify its reaction to electromagnetic fields and has kept the problem open. A successful alternative to the very difficult one of performing measurements is that of computing the fields within a human body model using numerical methods implemented in a software code. One of the difficulties is represented by the fact that some tissue types exhibit an anisotropic character with respect to their dielectric properties. Our work consists of computing currents induced by extremely low frequency (ELF electric fields in anisotropic muscle tissues using in this respect, a human body model extended with muscle fibre orientations as well as an extended version of the Finite Integration Technique (FIT able to compute fully anisotropic dielectric properties.

  14. Remote field eddy current technique for gap measurement of horizontal flux detector guide tube in pressurized heavy water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Hoon; Jung, Hyun Kyu; Yang, Dong Ju; Cheong, Yong Moo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2004-11-15

    The fuel channels including the pressure tube(PT) and the calandria tube(CT) are important components of the pressurized heavy water reactor(PHWR). A sagging of fuel channel increases by heat and radiation exposure with the increasing operation time. The contact of fuel channel to the Horizontal flux Detector(HFD) guide tube is needed for the power plant safety. In order to solve this safety issue, the electromagnetic technique was applied to measure the status of the guide tube. The Horizontal flux Detector(HFD) guide tube and the Calandria tube(CT) in the Pressurized Heavy Water Reactor(PHWR) are cross-aligned horizontally. The remote field eddy current(RFEC) technology is applied for gap measurement between the HFD guide tube and the CT HFD guide tube can be detected by inserting the RFEC probe into pressure tube(PT) at the crossing point directly. The RFEC signals using the volume integral method(VIM) were simulated for obtaining the optimal inspection parameters. This paper shows that the simulated eddy current signals and the experimental results in variance with the CT/HFD gap.

  15. Application of a Lamb waves based technique for structural health monitoring of GFRP undercyclic loading

    Science.gov (United States)

    Eremin, A.; Byakov, A.; Panin, S.; Burkov, M.; Lyubutin, P.; Sunder, R.

    2016-04-01

    A Lamb wave based ultrasonic technique as well as optical image characterization was utilized to estimate a current mechanical state of glass fiber reinforced polymers (GFRP) under cyclic tension. The ultrasonic acoustic method was applied in a 'pitch-catch' mode using piezoelectric transducers adhesively bonded onto a specimen surface. Numerical evaluation of acoustic data was performed by calculating two informative parameters: maximum of amplitude of the received signal and variance of signal envelopes. Optical images were registered and then analysed by calculating Shannon entropy that makes it possible to characterize changing of GFRP specimen translucency. The obtained results were treated in order to find out the relation between the current mechanical state of a specimen and informative parameter values being computed from the acoustic and optical signals.

  16. Application of Self Nulling Eddy Current Probe Technique to the Detection of Fatigue Crack Initiation and Control of Test Procedures

    Science.gov (United States)

    Namkung, M.; Nath, S.; Wincheski, B.; Fulton, J. P.

    1994-01-01

    A major part of fracture mechanics is concerned with studying the initiation and propagation of fatigue cracks. This typically requires constant monitoring of crack growth during fatigue cycles and the knowledge of the precise location of the crack tip at any given time. One technique currently available for measuring fatigue crack length is the Potential Drop method. The method, however, may be inaccurate if the direction of crack growth deviates considerably from what was assumed initially or the curvature of the crack becomes significant. Another popular approach is to optically view the crack using a high magnification microscope, but this entails a person constantly monitoring it. The present proposed technique uses an automated scheme, in order to eliminate the need for a person to constantly monitor the experiment. Another technique under development elsewhere is to digitize an optical image of the test specimen surface and then apply a pattern recognition algorithm to locate the crack tip. A previous publication showed that the self nulling eddy current probe successfully tracked a simulated crack in an aluminum sample. This was the impetus to develop an online real time crack monitoring system. An automated system has been developed which includes a two axis scanner mounted on the tensile testing machine, the probe and its instrumentation and a personal computer (PC) to communicate and control all the parameters. The system software controls the testing parameters as well as monitoring the fatigue crack as it propagates. This paper will discuss the experimental setup in detail and demonstrate its capabilities. A three dimensional finite element model is utilized to model the magnetic field distribution due to the probe and how the probe voltage changes as it scans the crack. Experimental data of the probe for different samples under zero load, static load and high cycle fatigue load will be discussed. The final section summarizes the major accomplishments

  17. HIGH-CURRENT ERL-BASED ELECTRON COOLING FOR RHIC.

    Energy Technology Data Exchange (ETDEWEB)

    BEN-ZVI, I.

    2005-09-18

    The design of an electron cooler must take into account both electron beam dynamics issues as well as the electron cooling physics. Research towards high-energy electron cooling of RHIC is in its 3rd year at Brookhaven National Laboratory. The luminosity upgrade of RHIC calls for electron cooling of various stored ion beams, such as 100 GeV/A gold ions at collision energies. The necessary electron energy of 54 MeV is clearly out of reach for DC accelerator system of any kind. The high energy also necessitates a bunched beam, with a high electron bunch charge, low emittance and small energy spread. The Collider-Accelerator Department adopted the Energy Recovery Linac (ERL) for generating the high-current, high-energy and high-quality electron beam. The RHIC electron cooler ERL will use four Superconducting RF (SRF) 5-cell cavities, designed to operate at ampere-class average currents with high bunch charges. The electron source will be a superconducting, 705.75 MHz laser-photocathode RF gun, followed up by a superconducting Energy Recovery Linac (ERL). An R&D ERL is under construction to demonstrate the ERL at the unprecedented average current of 0.5 amperes. Beam dynamics performance and luminosity enhancement are described for the case of magnetized and non-magnetized electron cooling of RHIC.

  18. Bio-inspired computational techniques based on advanced condition monitoring

    Institute of Scientific and Technical Information of China (English)

    Su Liangcheng; He Shan; Li Xiaoli; Li Xinglin

    2011-01-01

    The application of bio-inspired computational techniques to the field of condition monitoring is addressed.First, the bio-inspired computational techniques are briefly addressed; the advantages and disadvantages of these computational methods are made clear. Then, the roles of condition monitoring in the predictive maintenance and failures prediction and the development trends of condition monitoring are discussed. Finally, a case study on the condition monitoring of grinding machine is described, which shows the application of bio-inspired computational technique to a practical condition monitoring system.

  19. A New Image Steganography Based On First Component Alteration Technique

    Directory of Open Access Journals (Sweden)

    Amanpreet Kaur

    2009-12-01

    Full Text Available In this paper, A new image steganography scheme is proposed which is a kind of spatial domain technique. In order to hide secret data in cover-image, the first component alteration technique is used. Techniques used so far focuses only on the two or four bits of a pixel in a image (at the most five bits at the edge of an image which results in less peak to signal noise ratio and high root mean square error. In this technique, 8 bits of blue components of pixels are replaced with secret data bits. Proposed scheme can embed more data than previous schemes and shows better image quality. To prove this scheme, several experiments are performed, and are compared the experimental results with the related previous works.Keywords—image; mean square error; Peak signal to noise ratio; steganography;

  20. an architecture-based technique to mobile contact recommendation ...

    African Journals Online (AJOL)

    user

    the direct discriminative pattern mining, and the Bayesian Inference Network technique were used to formulate the. ECRM. ... Facebook, YouTube(and other social media platforms) ...... Measurement: A White Paper for Marketing that Keeps.