Sensorless Control of Permanent Magnet Machine for NASA Flywheel Technology Development

Science.gov (United States)

Kenny, Barbara H.; Kascak, Peter E.

2002-01-01

This paper describes the position sensorless algorithms presently used in the motor control for the NASA "in-house" development work of the flywheel energy storage system. At zero and low speeds a signal injection technique, the self-sensing method, is used to determine rotor position. At higher speeds, an open loop estimate of the back EMF of the machine is made to determine the rotor position. At start up, the rotor is set to a known position by commanding dc into one of the phase windings. Experimental results up to 52,000 rpm are presented.

An Approach to Sensorless Detection of Human Input Torque and Its Application to Power Assist Motion in Electric Wheelchair

Science.gov (United States)

Kaida, Yukiko; Murakami, Toshiyuki

A wheelchair is an important apparatus of mobility for people with disability. Power-assist motion in an electric wheelchair is to expand the operator's field of activities. This paper describes force sensorless detection of human input torque. Reaction torque estimation observer calculates the total disturbance torque first. Then, the human input torque is extracted from the estimated disturbance. In power-assist motion, assist torque is synthesized according to the product of assist gain and the average torque of the right and left input torque. Finally, the proposed method is verified through the experiments of power-assist motion.

The study on the Sensorless PMSM Control using the Superposition Theory

Energy Technology Data Exchange (ETDEWEB)

Hong, Joung Pyo [Changwon National University, Changwon (Korea); Kwon, Soon Jae [Pukung National University, Seoul (Korea); Kim, Gyu Seob; Sohn, Mu Heon; Kim, Jong Dal [Dongmyung College, Pusan (Korea)

2002-07-01

This study presents a solution to control a Permanent Magnet Synchronous Motor without sensors. The control method is the presented superposition principle. This method of sensorless theory is very simple to compute estimated angle. Therefore computing time to estimate angle is shorter than other sensorless method. The use of this system yields enhanced operations, fewer system components, lower system cost, energy efficient control system design and increased deficiency. A practical solution is described and results are given in this Study. The performance of a Sensorless architecture allows an intelligent approach to reduce the complete system costs of digital motion control applications using cheaper electrical motors without sensors. This paper deals with an overview of sensorless solutions in PMSM control applications whereby the focus will be the new controller without sensors and its applications. (author). 6 refs., 16 figs., 1 tab.

I-f Starting and Active Flux Based Sensorless Vector Control of Reluctance Synchronous Motors, with Experiments

DEFF Research Database (Denmark)

Agarlita, Sorin-Christian; Fatu, M.; Tutelea, L. N.

2010-01-01

This paper presents a novel, hybrid, motion sensorless control of an axially laminated anisotropic (ALA) reluctance synchronous machine (RSM). By separately controlling Id and Iq currents with the reference currents Id*, Iq* being held constant, and ramping the reference frequency, the motor starts...

Sensorless Control of IM for Limp-Home Mode EV Applications

DEFF Research Database (Denmark)

Dehghan-Azad, Ehsan; Gadoue, Shady; Atkinson, David

2017-01-01

in electric vehicle (EV) applications. The proposed scheme was experimentally tested on a laboratory dynamometer using a 19-kW IM and a 29-kW controller, which are both currently used in the automotive industry for EV applications. The scheme was also implemented on an electric golf buggy which was equipped......This paper presents a novel speed estimation scheme for induction motors (IMs) based on back electromotive-force model reference adaptive system (back-EMF MRAS). The scheme is employed for the purpose of sensorless fault-Tolerant torque-controlled drives used in a limp-home mode operation...... investigated for vehicle starting from standstill, wide speed range including field weakening region, and hill-starting operations. The proposed scheme is computationally easy to implement, robust against sensitivity to parameters variations, inverter nonlinearity and errors due to digitization in the field...

Sensorless load torque estimation and passivity based control of buck converter fed DC motor.

Science.gov (United States)

Kumar, S Ganesh; Thilagar, S Hosimin

2015-01-01

Passivity based control of DC motor in sensorless configuration is proposed in this paper. Exact tracking error dynamics passive output feedback control is used for stabilizing the speed of Buck converter fed DC motor under various load torques such as constant type, fan type, propeller type, and unknown load torques. Under load conditions, sensorless online algebraic approach is proposed, and it is compared with sensorless reduced order observer approach. The former produces better response in estimating the load torque. Sensitivity analysis is also performed to select the appropriate control variables. Simulation and experimental results fully confirm the superiority of the proposed approach suggested in this paper.

Novel Sensorless Six-Step Communication Strategy for a Surface Permanent Magnet Synchronous Motor with DC Link Measurement

DEFF Research Database (Denmark)

Munteanu, A.; Agarlita, S. C.; Blaabjerg, Frede

2012-01-01

The present paper introduces a novel six-step commutation strategy for sensorless control applied for a surface permanent magnet synchronous motor that implies only dc link measurement (battery current and battery voltage). The control strategy makes use of a modified I-f starting procedure and t......-crossing of the back-emf are obtained from an observer that uses both current and battery voltage. The case study is represented by a surface permanent magnet synchronous motor prototype (6 /8 configuration), designed for the automotive air conditioning compressor drive....

Fault detection Based Bayesian network and MOEA/D applied to Sensorless Drive Diagnosis

Directory of Open Access Journals (Sweden)

Zhou Qing

2017-01-01

Full Text Available Sensorless Drive Diagnosis can be used to assess the process data without the need for additional cost-intensive sensor technology, and you can understand the synchronous motor and connecting parts of the damaged state. Considering the number of features involved in the process data, it is necessary to perform feature selection and reduce the data dimension in the process of fault detection. In this paper, the MOEA / D algorithm based on multi-objective optimization is used to obtain the weight vector of all the features in the original data set. It is more suitable to classify or make decisions based on these features. In order to ensure the fastness and convenience sensorless drive diagnosis, in this paper, the classic Bayesian network learning algorithm-K2 algorithm is used to study the network structure of each feature in sensorless drive, which makes the fault detection and elimination process more targeted.

Thermo-emf of cermet films based on rare earth borides

International Nuclear Information System (INIS)

Islamgaliev, R.K.; Zyrin, A.V.; Shulishova, O.I.; Shcherbak, I.A

1987-01-01

Thermo-emf and electric conductivity of granulated films which contain a solid solution of europium and praseodymium borides Eu 0.5 Pr 0.5 B 6 as a conducting phase, and glass-crystal binder on the base of alummomagnesial fluosilicates as a dielectric phase are studied within the temperature range of 100-1100 K. Thermo-emf of films has a negative sign within the temperature range of 100-500 K and does not exceed 5 μkV/K according to the absolute value which is close to the value of the conducting phase thermo-emf. A negative sign and a small value of thermo-emf are indicative of the charge transfer in granulated films by electrons. Contribution of each of the components into the general thermo-emf is different at high temperatures in different temperature ranges and depends on the individual physico-chemical properties of the used materials

A sensor-less methanol concentration control system based on feedback from the stack temperature

International Nuclear Information System (INIS)

An, Myung-Gi; Mehmood, Asad; Ha, Heung Yong

2014-01-01

Highlights: • A new sensor-less methanol control algorithm based on feedback from the stack temperature is developed. • Feasibility of the algorithm is tested using a DMFC system with a recirculating fuel loop. • The algorithm precisely controls the methanol concentration without the use of methanol sensors. • The sensor-less controller shortens the time that the DMFC system requires to go from start-up to steady-state. • This controller is effective in handling unexpected changes in the methanol concentration and stack temperature. - Abstract: A sensor-less methanol concentration control system based on feedback from the stack temperature (SLCCF) has been developed. The SLCCF algorithm is embedded into an in-house LabVIEW program that has been developed to control the methanol concentration in the feed of direct methanol fuel cells (DMFCs). This control method utilizes the close correlation between the stack temperature and the methanol concentration in the feed. Basically, the amounts of methanol to be supplied to the re-circulating feed stream are determined by estimating the methanol consumption rates under given operating conditions, which are then adjusted by a proportional–integral controller and supplied into the feed stream to maintain the stack temperature at a set value. The algorithm is designed to control the methanol concentration and the stack temperature for both start-up and normal operation processes. Feasibility tests with a 200 W-class DMFC system under various operating conditions confirm that the algorithm successfully maintains the methanol concentration in the feed as well as the stack temperature at set values, and the start-up time required for the DMFC system to reach steady-state operating conditions is reduced significantly compared with conventional sensor-less methods

Analysis of sensorless control of brushless DC motor using unknown input observer with different gains

Science.gov (United States)

Astik, Mitesh B.; Bhatt, Praghnesh; Bhalja, Bhavesh R.

2017-03-01

A sensorless control scheme based on an unknown input observer is presented in this paper in which back EMF of the Brushless DC Motor (BLDC) is continuously estimated from available line voltages and currents. During negative rotation of motor, actual and estimated speed fail to track the reference speed and if the corrective action is not taken by the observer, the motor goes into saturation. To overcome this problem, the speed estimation algorithm has been implemented in this paper to control the dynamic behavior of the motor during negative rotation. The Ackermans method was used to calculate the gains of an unknown input observer which is based on the appropriate choice of the eigenvalues in advance. The criteria to choose eigenvalue is to obtain a balance between faster convergence rate and the least noise level. Simulations have been carried out for different disturbances such as step changes in motor reference speed and load torque. The comparative simulation results clearly depict that the disturbance effects in actual and estimated responses minimizes as observer gain setting increases.

Contrast-based sensorless adaptive optics for retinal imaging.

Science.gov (United States)

Zhou, Xiaolin; Bedggood, Phillip; Bui, Bang; Nguyen, Christine T O; He, Zheng; Metha, Andrew

2015-09-01

Conventional adaptive optics ophthalmoscopes use wavefront sensing methods to characterize ocular aberrations for real-time correction. However, there are important situations in which the wavefront sensing step is susceptible to difficulties that affect the accuracy of the correction. To circumvent these, wavefront sensorless adaptive optics (or non-wavefront sensing AO; NS-AO) imaging has recently been developed and has been applied to point-scanning based retinal imaging modalities. In this study we show, for the first time, contrast-based NS-AO ophthalmoscopy for full-frame in vivo imaging of human and animal eyes. We suggest a robust image quality metric that could be used for any imaging modality, and test its performance against other metrics using (physical) model eyes.

Development of sensorless easy-to-use overhead crane system via simulation based control

Science.gov (United States)

Tagawa, Yasutaka; Mori, Yoshihito; Wada, Masaomi; Kawajiri, Eisaku; Nouzuka, Kazuma

2016-09-01

This paper describes the newly developed overhead crane which has a sensorless vibration control system. Generally, loads which are carried by the overhead cranes are easy to vibrate and only skilled people can operate the cranes. Therefore, a lot of studies have been done to solve this problem by using feedback control with vibration sensors. However vibration sensors often break down in severe industrial environment and more reliable control systems are required. For this reason, we have been developing sensorless control system for overhead cranes. In this paper, we firstly introduce basic idea of simulation based control which is called IDCS, then overview and modeling of the overhead crane is presented. Next, the control system design of the overhead crane is discussed, and experimental results are shown for real overhead crane with 2 axes.

Wavefront sensorless adaptive optics ophthalmoscopy in the human eye

Science.gov (United States)

Hofer, Heidi; Sredar, Nripun; Queener, Hope; Li, Chaohong; Porter, Jason

2011-01-01

Wavefront sensor noise and fidelity place a fundamental limit on achievable image quality in current adaptive optics ophthalmoscopes. Additionally, the wavefront sensor ‘beacon’ can interfere with visual experiments. We demonstrate real-time (25 Hz), wavefront sensorless adaptive optics imaging in the living human eye with image quality rivaling that of wavefront sensor based control in the same system. A stochastic parallel gradient descent algorithm directly optimized the mean intensity in retinal image frames acquired with a confocal adaptive optics scanning laser ophthalmoscope (AOSLO). When imaging through natural, undilated pupils, both control methods resulted in comparable mean image intensities. However, when imaging through dilated pupils, image intensity was generally higher following wavefront sensor-based control. Despite the typically reduced intensity, image contrast was higher, on average, with sensorless control. Wavefront sensorless control is a viable option for imaging the living human eye and future refinements of this technique may result in even greater optical gains. PMID:21934779

Sensorless Characteristics of Hybrid PM Machines at Zero and Low Speed

DEFF Research Database (Denmark)

Matzen, Torben N.; Rasmussen, Peter Omand

2009-01-01

Sensorless methods for zero and low speed operation in drives with hybrid PM machines make use of the machine saliency to determine the rotor position in an indirect fashion. When integrating the position measurement in the electrical power supply to the machine, i.e. make the machine self......-sensing, the sensorless obtained position can be affected by the actual operation conditions of the machine e.g. the stator currents. This may deteriorate the machine self-sensing suitability using injection methods. In this paper an analysis method based on accurate knowledge of the machine flux linkages is proposed...... for analysing the suitability for sensorless control at zero and low speed. The method can be used to evaluate a particular machine design so the self-sensing characteristics for sensorless control of machine can be found. The characteristics can be obtained from finite element simulation data or experimental...

Simple Power Control for Sensorless Induction Motor Drives Fed by a Matrix Converter

DEFF Research Database (Denmark)

Blaabjerg, Frede; Lee, Kyo Beum

2008-01-01

This paper presents a new and simple method for sensorless control of matrix converter drives using a power flowing to the motor. The proposed control algorithm is based on controlling the instantaneous real and imaginary powers into the induction motor. To improve low-speed sensorless performance...

Modelling of BLDCM with a double 3-phase stator winding and back EMF harmonics

Directory of Open Access Journals (Sweden)

Drozdowski Piotr

2015-03-01

Full Text Available In this paper the mathematical model of the brushless DC motor (BLDCM with a double 3-phase stator winding is analysed. Both the 3-phase windings are mutually displaced by 30 electrical degree. Special care has been sacrificed to influence of higher harmonics of induced electromotive forces (EMF on electromagnetic torque and zero sequence voltages that may be used for sensorless control. The mathematical model has been presented in natural variables and, after transformation to symmetrical components, in a vector form. This allows, from one side, for formulating the equivalent circuit suitable for circuit oriented simulators (e.g.: Spice, SimPowerSystems of Simulink and, from the other point of view, for analysis of higher harmonics influence on control possibilities. These considerations have been illustrated with some results of four quadrant operation obtainded due to simulation at automatic control.

Optimal model-based sensorless adaptive optics for epifluorescence microscopy.

Science.gov (United States)

Pozzi, Paolo; Soloviev, Oleg; Wilding, Dean; Vdovin, Gleb; Verhaegen, Michel

2018-01-01

We report on a universal sample-independent sensorless adaptive optics method, based on modal optimization of the second moment of the fluorescence emission from a point-like excitation. Our method employs a sample-independent precalibration, performed only once for the particular system, to establish the direct relation between the image quality and the aberration. The method is potentially applicable to any form of microscopy with epifluorescence detection, including the practically important case of incoherent fluorescence emission from a three dimensional object, through minor hardware modifications. We have applied the technique successfully to a widefield epifluorescence microscope and to a multiaperture confocal microscope.

Implementation of a sliding-mode-based position sensorless drive for high-speed micro permanent-magnet synchronous motors.

Science.gov (United States)

Chi, Wen-Chun; Cheng, Ming-Yang

2014-03-01

Due to issues such as limited space, it is difficult if it is not impossible to employ a position sensor in the drive control of high-speed micro PMSMs. In order to alleviate this problem, this paper analyzes and implements a simple and robust position sensorless field-oriented control method of high-speed micro PMSMs based on the sliding-mode observer. In particular, the angular position and velocity of the rotor of the high-speed micro PMSM are estimated using the sliding-mode observer. This observer is able to accurately estimate rotor position in the low speed region and guarantee fast convergence of the observer in the high speed region. The proposed position sensorless control method is suitable for electric dental handpiece motor drives where a wide speed range operation is essential. The proposed sensorless FOC method is implemented using a cost-effective 16-bit microcontroller and tested in a prototype electric dental handpiece motor. Several experiments are performed to verify the effectiveness of the proposed method. © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Bi Input-extended Kalman filter based estimation technique for speed-sensorless control of induction motors

International Nuclear Information System (INIS)

Barut, Murat

2010-01-01

This study offers a novel extended Kalman filter (EKF) based estimation technique for the solution of the on-line estimation problem related to uncertainties in the stator and rotor resistances inherent to the speed-sensorless high efficiency control of induction motors (IMs) in the wide speed range as well as extending the limited number of states and parameter estimations possible with a conventional single EKF algorithm. For this aim, the introduced estimation technique in this work utilizes a single EKF algorithm with the consecutive execution of two inputs derived from the two individual extended IM models based on the stator resistance and rotor resistance estimation, differently from the other approaches in past studies, which require two separate EKF algorithms operating in a switching or braided manner; thus, it has superiority over the previous EKF schemes in this regard. The proposed EKF based estimation technique performing the on-line estimations of the stator currents, the rotor flux, the rotor angular velocity, and the load torque involving the viscous friction term together with the rotor and stator resistance is also used in the combination with the speed-sensorless direct vector control of IM and tested with simulations under the challenging 12 scenarios generated instantaneously via step and/or linear variations of the velocity reference, the load torque, the stator resistance, and the rotor resistance in the range of high and zero speed, assuming that the measured stator phase currents and voltages are available. Even under those variations, the performance of the speed-sensorless direct vector control system established on the novel EKF based estimation technique is observed to be quite good.

Bi Input-extended Kalman filter based estimation technique for speed-sensorless control of induction motors

Energy Technology Data Exchange (ETDEWEB)

Barut, Murat, E-mail: muratbarut27@yahoo.co [Nigde University, Department of Electrical and Electronics Engineering, 51245 Nigde (Turkey)

2010-10-15

This study offers a novel extended Kalman filter (EKF) based estimation technique for the solution of the on-line estimation problem related to uncertainties in the stator and rotor resistances inherent to the speed-sensorless high efficiency control of induction motors (IMs) in the wide speed range as well as extending the limited number of states and parameter estimations possible with a conventional single EKF algorithm. For this aim, the introduced estimation technique in this work utilizes a single EKF algorithm with the consecutive execution of two inputs derived from the two individual extended IM models based on the stator resistance and rotor resistance estimation, differently from the other approaches in past studies, which require two separate EKF algorithms operating in a switching or braided manner; thus, it has superiority over the previous EKF schemes in this regard. The proposed EKF based estimation technique performing the on-line estimations of the stator currents, the rotor flux, the rotor angular velocity, and the load torque involving the viscous friction term together with the rotor and stator resistance is also used in the combination with the speed-sensorless direct vector control of IM and tested with simulations under the challenging 12 scenarios generated instantaneously via step and/or linear variations of the velocity reference, the load torque, the stator resistance, and the rotor resistance in the range of high and zero speed, assuming that the measured stator phase currents and voltages are available. Even under those variations, the performance of the speed-sensorless direct vector control system established on the novel EKF based estimation technique is observed to be quite good.

Speed Sensorless Control of PMSM using Model Reference Adaptive System and RBFN

OpenAIRE

Wei Gao; Zhirong Guo

2013-01-01

In the speed sensorless vector control system, the amended method of estimating the rotor speed about model reference adaptive system (MRAS) based on radial basis function neural network (RBFN) for PMSM sensorless vector control system was presented. Based on the PI regulator, the radial basis function neural network which is more prominent learning efficiency and performance is combined with MRAS. The reference model and the adjust model are the PMSM itself and the PMSM current, respectively...

FUZZY LOGIC BASED ADAPTATION MECHANISM FOR ADAPTIVE LUENBERGER OBSERVER SENSORLESS DIRECT TORQUE CONTROL OF INDUCTION MOTOR

Directory of Open Access Journals (Sweden)

A. BENNASSAR

2016-01-01

Full Text Available Many industrial applications require high performance speed sensorless operation and demand new control methods in order to obtain fast dynamic response and insensitive to external disturbances. The current research aims to present the performance of the sensorless direct torque control (DTC of an induction motor (IM using adaptive Luenberger observer (ALO with fuzzy logic controller (FLC for adaptation mechanism. The rotor speed is regulated by proportional integral (PI anti-windup controller. The proposed strategy is directed to reduce the ripple on the torque and the flux. Numerical simulation results show the good performance and effectiveness of the proposed sensorless control for different references of the speed even both low and high speeds.

radio frequency emf radio frequency emf exposure due to gsm

African Journals Online (AJOL)

eobe

about electromagnetic field (EMF) radiation from base. Nigerian Journal of ... oscillate in phase perpendicular to each other as shown in ... and magnetic) is produced by a change in the other part and the ... limit). 4. MATERIALS AND METHOD.

Sensorless Control of IPMSM by Voltage Injection

DEFF Research Database (Denmark)

Matzen, Torben N.; Bech, Michael Møller

2006-01-01

In this paper a sensorless discrete current control of an Interior Permanent Magnet Synchrouns Motor (IPMSM) by voltage injection is designed and tested. The whole controller is operating in the dq-frame and for this reason the rotor position is essential to know, to transform between the station......In this paper a sensorless discrete current control of an Interior Permanent Magnet Synchrouns Motor (IPMSM) by voltage injection is designed and tested. The whole controller is operating in the dq-frame and for this reason the rotor position is essential to know, to transform between...... the stationary frame and the rotor xed dq-frame. To obtain the position even at standstill a sensorless scheme using voltage injection is added to the current controller....

Optimization of measurement methods for a multi-frequency electromagnetic field from mobile phone base station using broadband EMF meter

Directory of Open Access Journals (Sweden)

Paweł Bieńkowski

2015-10-01

Full Text Available Background: This paper presents the characteristics of the mobile phone base station (BS as an electromagnetic field (EMF source. The most common system configurations with their construction are described. The parameters of radiated EMF in the context of the access to methods and other parameters of the radio transmission are discussed. Attention was also paid to antennas that are used in this technology. Material and Methods: The influence of individual components of a multi-frequency EMF, most commonly found in the BS surroundings, on the resultant EMF strength value indicated by popular broadband EMF meters was analyzed. The examples of metrological characteristics of the most common EMF probes and 2 measurement scenarios of the multisystem base station, with and without microwave relays, are shown. Results: The presented method for measuring the multi-frequency EMF using 2 broadband probes allows for the significant minimization of measurement uncertainty. Equations and formulas that can be used to calculate the actual EMF intensity from multi-frequency sources are shown. They have been verified in the laboratory conditions on a specific standard setup as well as in real conditions in a survey of the existing base station with microwave relays. Conclusions: Presented measurement methodology of multi-frequency EMF from BS with microwave relays, validated both in laboratory and real conditions. It has been proven that the described measurement methodology is the optimal approach to the evaluation of EMF exposure in BS surrounding. Alternative approaches with much greater uncertainty (precaution method or more complex measuring procedure (sources exclusion method are also presented. Med Pr 2015;66(5:701–712

[Optimization of measurement methods for a multi-frequency electromagnetic field from mobile phone base station using broadband EMF meter].

Science.gov (United States)

Bieńkowski, Paweł; Cała, Paweł; Zubrzak, Bartłomiej

2015-01-01

This paper presents the characteristics of the mobile phone base station (BS) as an electromagnetic field (EMF) source. The most common system configurations with their construction are described. The parameters of radiated EMF in the context of the access to methods and other parameters of the radio transmission are discussed. Attention was also paid to antennas that are used in this technology. The influence of individual components of a multi-frequency EMF, most commonly found in the BS surroundings, on the resultant EMF strength value indicated by popular broadband EMF meters was analyzed. The examples of metrological characteristics of the most common EMF probes and 2 measurement scenarios of the multisystem base station, with and without microwave relays, are shown. The presented method for measuring the multi-frequency EMF using 2 broadband probes allows for the significant minimization of measurement uncertainty. Equations and formulas that can be used to calculate the actual EMF intensity from multi-frequency sources are shown. They have been verified in the laboratory conditions on a specific standard setup as well as in real conditions in a survey of the existing base station with microwave relays. Presented measurement methodology of multi-frequency EMF from BS with microwave relays, validated both in laboratory and real conditions. It has been proven that the described measurement methodology is the optimal approach to the evaluation of EMF exposure in BS surrounding. Alternative approaches with much greater uncertainty (precaution method) or more complex measuring procedure (sources exclusion method) are also presented). This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

EUROPAEM EMF Guideline 2016 for the prevention, diagnosis and treatment of EMF-related health problems and illnesses.

Science.gov (United States)

Belyaev, Igor; Dean, Amy; Eger, Horst; Hubmann, Gerhard; Jandrisovits, Reinhold; Kern, Markus; Kundi, Michael; Moshammer, Hanns; Lercher, Piero; Müller, Kurt; Oberfeld, Gerd; Ohnsorge, Peter; Pelzmann, Peter; Scheingraber, Claus; Thill, Roby

2016-09-01

Chronic diseases and illnesses associated with non-specific symptoms are on the rise. In addition to chronic stress in social and work environments, physical and chemical exposures at home, at work, and during leisure activities are causal or contributing environmental stressors that deserve attention by the general practitioner as well as by all other members of the health care community. It seems necessary now to take "new exposures" like electromagnetic fields (EMF) into account. Physicians are increasingly confronted with health problems from unidentified causes. Studies, empirical observations, and patient reports clearly indicate interactions between EMF exposure and health problems. Individual susceptibility and environmental factors are frequently neglected. New wireless technologies and applications have been introduced without any certainty about their health effects, raising new challenges for medicine and society. For instance, the issue of so-called non-thermal effects and potential long-term effects of low-dose exposure were scarcely investigated prior to the introduction of these technologies. Common electromagnetic field or EMF sources: Radio-frequency radiation (RF) (3 MHz to 300 GHz) is emitted from radio and TV broadcast antennas, Wi-Fi access points, routers, and clients (e.g. smartphones, tablets), cordless and mobile phones including their base stations, and Bluetooth devices. Extremely low frequency electric (ELF EF) and magnetic fields (ELF MF) (3 Hz to 3 kHz) are emitted from electrical wiring, lamps, and appliances. Very low frequency electric (VLF EF) and magnetic fields (VLF MF) (3 kHz to 3 MHz) are emitted, due to harmonic voltage and current distortions, from electrical wiring, lamps (e.g. compact fluorescent lamps), and electronic devices. On the one hand, there is strong evidence that long-term exposure to certain EMFs is a risk factor for diseases such as certain cancers, Alzheimer's disease, and male infertility. On the other hand

Speed-sensorless control strategy for multi-phase induction generator in wind energy conversion systems

Directory of Open Access Journals (Sweden)

Dumnić Boris P.

2016-01-01

Full Text Available Renewable energy sources, especially wind energy conversion systems (WECS, exhibit constant growth. Increase in power and installed capacity led to advances in WECS topologies. Multi-phase approach presents a new development direction, with several key advantages over three-phase systems. Paired with a sensorless control strategy, multi-phase machines are expected to take primacy over standard solutions. This paper presents speed sensorless vector control of an asymmetrical six-phase induction generator based on a model reference adaptive system (MRAS. Suggested topology and developed control algorithm show that sensorless control can yield appropriate dynamic characteristics for the use in WECS with increase in reliability and robustness. [Projekat Ministarstva nauke Republike Srbije, br. III 042004: Smart Electricity Distribution Grids Based on Distribution Management System and Distributed Generation

Sensorless control of low-cost single-phase hybrid switched reluctance motor drive

DEFF Research Database (Denmark)

Jakobsen, Uffe; Lu, Kaiyuan; Rasmussen, Peter Omand

2013-01-01

This paper presents a sensorless-controlled, low-cost, low-power, variable-speed drive system suitable for fan and pump applications. The main advantages of this drive system are the low system cost, simple converter structure, and simple but robust sensorless control technique. The drive motor...... is a special Hybrid Switched Reluctance Motor (HSRM). The proposed sensorless control method utilizes beneficially the stator side permanent magnet field and its performance is motor parameter independent. The unique low-cost drive system solution, simple and robust sensorless control features of this drive...

Sensorless Control of Low-cost Single-phase Hybrid Switched Reluctance Motor Drive

DEFF Research Database (Denmark)

Jakobsen, Uffe; Lu, Kaiyuan; Rasmussen, Peter Omand

2015-01-01

This paper presents a sensorless-controlled, low-cost, low-power, and variable-speed drive system suitable for fan and pump applications. The main advantages of this drive system are the low system cost, simple converter structure, and simple but robust sensorless control technique. The drive motor...... is a special hybrid switched reluctance motor. The proposed sensorless control method beneficially utilizes the stator side PM field and its performance is motor parameter independent. The unique low-cost drive system solution, simple and robust sensorless control features of this drive system, is demonstrated...

EMF Monitoring—Concepts, Activities, Gaps and Options

Directory of Open Access Journals (Sweden)

Gregor Dürrenberger

2014-09-01

Full Text Available Exposure to electromagnetic fields (EMF is a cause of concern for many people. The topic will likely remain for the foreseeable future on the scientific and political agenda, since emissions continue to change in characteristics and levels due to new infrastructure deployments, smart environments and novel wireless devices. Until now, systematic and coordinated efforts to monitor EMF exposure are rare. Furthermore, virtually nothing is known about personal exposure levels. This lack of knowledge is detrimental for any evidence-based risk, exposure and health policy, management and communication. The main objective of the paper is to review the current state of EMF exposure monitoring activities in Europe, to comment on the scientific challenges and deficiencies, and to describe appropriate strategies and tools for EMF exposure assessment and monitoring to be used to support epidemiological health research and to help policy makers, administrators, industry and consumer representatives to base their decisions and communication activities on facts and data.

Sensorless sliding mode torque control of an IPMSM drive based on active flux concept

Directory of Open Access Journals (Sweden)

A.A. Hassan

2012-03-01

Full Text Available This paper investigates a novel direct torque control of a sensorless interior permanent magnet synchronous motor based on a sliding mode technique. The speed and position of the interior permanent magnet synchronous motor are estimated online based on active flux concept. To overcome the large ripple content associated with the direct torque, a torque/flux sliding mode controller has been employed. Two integral surface functions are used to construct the sliding mode controller. The command voltage is estimated from the torque and flux errors based on the two switching functions. The idea of the total sliding mode is used to eliminate the problem of reaching phase stability. The space vector modulation is combined with the sliding mode controller to ensure minimum torque and flux ripples and provides high resolution voltage control. The proposed scheme has the advantages of simple implementation, and does not require an external signal injection. In addition, it combines the merits of the direct torque control, sliding mode controller, and space vector modulation besides to the sensorless control. Simulation works are carried out to demonstrate the ability of the proposed scheme at different operating conditions. The results confirm the high performance of the proposed scheme at standstill, low and high speeds including load disturbance and parameters variation.

Comparison of sensorless dimming control based on building modeling and solar power generation

International Nuclear Information System (INIS)

Lee, Naeun; Kim, Jonghun; Jang, Cheolyong; Sung, Yoondong; Jeong, Hakgeun

2015-01-01

Artificial lighting in office buildings accounts for about 30% of the total building energy consumption. Lighting energy is important to reduce building energy consumption since artificial lighting typically has a relatively large energy conversion factor. Therefore, previous studies have proposed a dimming control using daylight. When applied dimming control, method based on building modeling does not need illuminance sensors. Thus, it can be applied to existing buildings that do not have illuminance sensors. However, this method does not accurately reflect real-time weather conditions. On the other hand, solar power generation from a PV (photovoltaic) panel reflects real-time weather conditions. The PV panel as the sensor improves the accuracy of dimming control by reflecting disturbance. Therefore, we compared and analyzed two types of sensorless dimming controls: those based on the building modeling and those that based on solar power generation using PV panels. In terms of energy savings, we found that a dimming control based on building modeling is more effective than that based on solar power generation by about 6%. However, dimming control based on solar power generation minimizes the inconvenience to occupants and can also react to changes in solar radiation entering the building caused by dirty window. - Highlights: • We conducted sensorless dimming control based on solar power generation. • Dimming controls using building modeling and solar power generation were compared. • The real time weather conditions can be considered by using solar power generation. • Dimming control using solar power generation minimizes inconvenience to occupants

Novel high accurate sensorless dual-axis solar tracking system controlled by maximum power point tracking unit of photovoltaic systems

International Nuclear Information System (INIS)

Fathabadi, Hassan

2016-01-01

Highlights: • Novel high accurate sensorless dual-axis solar tracker. • It has the advantages of both sensor based and sensorless solar trackers. • It does not have the disadvantages of sensor based and sensorless solar trackers. • Tracking error of only 0.11° that is less than the tracking errors of others. • An increase of 28.8–43.6% depending on the seasons in the energy efficiency. - Abstract: In this study, a novel high accurate sensorless dual-axis solar tracker controlled by the maximum power point tracking unit available in almost all photovoltaic systems is proposed. The maximum power point tracking controller continuously calculates the maximum output power of the photovoltaic module/panel/array, and uses the altitude and azimuth angles deviations to track the sun direction where the greatest value of the maximum output power is extracted. Unlike all other sensorless solar trackers, the proposed solar tracking system is a closed loop system which means it uses the actual direction of the sun at any time to track the sun direction, and this is the contribution of this work. The proposed solar tracker has the advantages of both sensor based and sensorless dual-axis solar trackers, but it does not have their disadvantages. Other sensorless solar trackers all are open loop, i.e., they use offline estimated data about the sun path in the sky obtained from solar map equations, so low exactness, cloudy sky, and requiring new data for new location are their problems. A photovoltaic system has been built, and it is experimentally verified that the proposed solar tracking system tracks the sun direction with the tracking error of 0.11° which is less than the tracking errors of other both sensor based and sensorless solar trackers. An increase of 28.8–43.6% depending on the seasons in the energy efficiency is the main advantage of utilizing the proposed solar tracking system.

A Position Sensorless Control Method for SRM Based on Variation of Phase Inductance

Science.gov (United States)

Komatsuzaki, Akitomo; Miki, Ichiro

Switched reluctance motor (SRM) drives are suitable for variable speed industrial applications because of the simple structure and high-speed capability. However, it is necessary to detect the rotor position with a position sensor attached to the motor shaft. The use of the sensor increases the cost of the drive system and machine size, and furthermore the reliability of the system is reduced. Therefore, several approaches to eliminate the position sensor have already been reported. In this paper, a position sensorless control method based on the variation of the phase inductance is described. The phase inductance regularly varies with the rotor position. The SRM is controlled without the position sensor using the de-fluxing period and the phase inductance. The turn-off timing is determined by computing the difference of angle between the sampling point and the aligned point and the variation of angle during the de-fluxing period. In the magnetic saturation region, the phase inductance at the current when the effect of the saturation starts is computed and the sensorless control can be carried out using this inductance. Experimental results show that the SRM is well controlled without the position sensor using the proposed method.

EUROPAEM EMF Guideline 2015 for the prevention, diagnosis and treatment of EMF-related health problems and illnesses.

Science.gov (United States)

Belyaev, Igor; Dean, Amy; Eger, Horst; Hubmann, Gerhard; Jandrisovits, Reinhold; Johansson, Olle; Kern, Markus; Kundi, Michael; Lercher, Piero; Mosgöller, Wilhelm; Moshammer, Hanns; Müller, Kurt; Oberfeld, Gerd; Ohnsorge, Peter; Pelzmann, Peter; Scheingraber, Claus; Thill, Roby

2015-01-01

Chronic diseases and illnesses associated with unspecific symptoms are on the rise. In addition to chronic stress in social and work environments, physical and chemical exposures at home, at work, and during leisure activities are causal or contributing environmental stressors that deserve attention by the general practitioner as well as by all other members of the health care community. It seems certainly necessary now to take "new exposures" like electromagnetic field (EMF) into account. Physicians are increasingly confronted with health problems from unidentified causes. Studies, empirical observations, and patient reports clearly indicate interactions between EMF exposure and health problems. Individual susceptibility and environmental factors are frequently neglected. New wireless technologies and applications have been introduced without any certainty about their health effects, raising new challenges for medicine and society. For instance, the issue of so-called non-thermal effects and potential long-term effects of low-dose exposure were scarcely investigated prior to the introduction of these technologies. Common EMF sources include Wi-Fi access points, routers and clients, cordless and mobile phones including their base stations, Bluetooth devices, ELF magnetic fields from net currents, ELF electric fields from electric lamps and wiring close to the bed and office desk. On the one hand, there is strong evidence that long-term-exposure to certain EMF exposures is a risk factor for diseases such as certain cancers, Alzheimer's disease and male infertility. On the other hand, the emerging electromagnetic hypersensitivity (EHS) is more and more recognized by health authorities, disability administrators and case workers, politicians, as well as courts of law. We recommend treating EHS clinically as part of the group of chronic multisystem illnesses (CMI) leading to a functional impairment (EHS), but still recognizing that the underlying cause remains the

Low Cost Sensorless Control of Permanent Magnet Motors

DEFF Research Database (Denmark)

Montesinos, Daniel; Galceran, Samuel; Blaabjerg, Frede

2005-01-01

This paper provides a review of the literature addressing sensorless operation of PM brushless machines. The methods explained are state-of-the-art of open and closed loop control strategies. The closed loop review includes those methods based on voltage and current measurements, and algebraic ma...

A Novel Method for Sensorless Speed Detection of Brushed DC Motors

Directory of Open Access Journals (Sweden)

Ernesto Vazquez-Sanchez

2016-12-01

Full Text Available Many motor applications require accurate speed measurement. For brushed dc motors, speed can be measured with conventional observers or sensorless observers. Sensorless observers have the advantage of not requiring any external devices to be attached to the motor. Instead, voltage and/or current are measured and used to estimate the speed. The sensorless observers are usually divided into two groups: those based on the dynamic model, and those based on the ripple component. This paper proposes a method that measures the current of brushed dc motors and analyses the position of its spectral components. From these spectral components, the method estimates the motor speed. Three tests, performed each with the speeds ranging from 2000 to 3000 rpm either at constant-speed, at slowly changing speeds, or at rapidly changing speeds, showed that the average error was below 1 rpm and that the deviation error was below 1.5 rpm. The proposed method: (i is a novel method that is not based on either the dynamic model or on the ripple component; (ii requires only the measurement of the current for the speed estimation; (iii can be used for brushed dc (direct current motors with a large number of coils; and (iv achieves a low error in the speed estimation.

A grid-voltage-sensorless resistive active power filter with series LC-filter

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

2017-01-01

Voltage-sensorless control has been investigated for Voltage Source Inverters (VSIs) for many years due to the reduced system cost and potentially improved system reliability. The VSI based Resistive Active Power Filters (R-APFs) are now widely used to prevent the harmonic resonance in power...... distribution network, for which the voltage sensors are needed in order to obtain the current reference. In this paper a grid-voltage-sensorless control strategy is proposed for the R-APF with series LC-filter. Unlike the traditional resistance emulation method, this proposed control method re...

A Grid-Voltage-Sensorless Resistive Active Power Filter with Series LC-Filter

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

2018-01-01

Voltage-sensorless control has been investigated for Voltage Source Inverters (VSIs) for many years due to the reduced system cost and potentially improved system reliability. The VSI based Resistive Active Power Filters (R-APFs) are now widely used to prevent the harmonic resonance in power...... distribution network, for which the voltage sensors are needed in order to obtain the current reference. In this paper a grid-voltage-sensorless control strategy is proposed for the R-APF with series LC-filter. Unlike the traditional resistance emulation method, this proposed control method re...

Sensorless soft starters for loaded induction motors

Energy Technology Data Exchange (ETDEWEB)

Chrisanov, V.I.; Konovalov, Y.N. [Power Plearonics Department, State University of Telecommunication, St. Petersburg (Russian Federation)

1997-12-31

The paper is devoted to the research and design of sensorless thyristor soft starters for loaded induction motors (IM) with short circuited squirrel case rotors. It is shown that the applied direct converter topology depends on the output power and consists of a small number of thyristors with special algorithm of switching to realize voltage - frequency control of IM drive systems at low speeds of starting. Sensorless control is realized from the both sides when neither direct converter nor drive system consists of any additional transducers for soft starting operation. (orig.) 4 refs.

Exposure Knowledge and Risk Perception of RF EMF

Science.gov (United States)

Freudenstein, Frederik; Wiedemann, Peter M.; Varsier, Nadège

2015-01-01

The presented study is part of the EU-Project Low EMF Exposure Future Networks (LEXNET), which deals among other things with the issue of whether a reduction of the radiofrequency (RF) electro-magnetic fields (EMF) exposure will result in more acceptance of wireless communication networks in the public sphere. We assume that the effects of any reduction of EMF exposure will depend on the subjective link between exposure perception and risk perception (RP). Therefore we evaluated respondents’ RP of different RF EMF sources and their subjective knowledge about various exposure characteristics with regard to their impact on potential health risks. The results show that participants are more concerned about base stations than about all other RF EMF sources. Concerning the subjective exposure knowledge the results suggest that people have a quite appropriate impact model. The question how RF EMF RP is actually affected by the knowledge about the various exposure characteristics was tested in a linear regression analysis. The regression indicates that these features – except distance – do influence people’s general RF EMF RP. In addition, we analyzed the effect of the quality of exposure knowledge on RF EMF RP of various sources. The results show a tendency that better exposure knowledge leads to higher RP, especially for mobile phones. The study provides empirical support for models of the relationships between exposure perception and RP. It is not the aim to extrapolate these findings to the whole population because the samples are not exactly representative for the general public in the participating countries. PMID:25629026

Exposure knowledge and risk perception of RF EMF

Directory of Open Access Journals (Sweden)

Frederik eFreudenstein

2015-01-01

Full Text Available The presented study is part of the EU Project LEXNET (Low EMF Exposure Future Networks, which deals among other things with the issue of whether a reduction of the radiofrequency (RF electro-magnetic fields (EMF exposure will result in more acceptance of wireless communication networks in the public sphere.We assume that the effects of any reduction of EMF exposure will depend on the subjective link between exposure perception and risk perception. Therefore we evaluated respondents’ risk perceptions of different RF EMF sources and their subjective knowledge about various exposure characteristics with regard to their impact on potential health risks. The results show that participants are more concerned about base stations than about all other RF EMF sources. Concerning the subjective exposure knowledge the results suggest that people have a quite appropriate impact model. The question how RF EMF risk perception is actually affected by the knowledge about the various exposure characteristics was tested in a linear regression analysis. The regression indicates that these features - except distance - do influence people’s general RF EMF risk perceptions. In addition, we analyzed the effect of the quality of exposure knowledge on RF EMF risk perception of various sources. The results show a tendency that better exposure knowledge leads to higher risk perception, especially for mobile phones. The study provides empirical support for models of the relationships between exposure perception and risk perception. It is not the aim to extrapolate these findings to the whole population because the samples are not exactly representative for the general public in the participating countries.

A Very Low-Speed Sensorless Induction Motor Drive with Online Stator Resistance identification scheme

Directory of Open Access Journals (Sweden)

M. Zaky

2008-03-01

Full Text Available Recently, speed sensorless control of induction motor drives received great attention to avoid the different problems associated with direct speed sensors. However, low speed operation with robustness against parameter variations remains an area of research for sensorless systems. Stator resistance is of greatest importance for good operation of speed sensorless systems in low speed region. In this paper, a sliding mode current observer for an induction motor is presented. An estimation algorithm based on this observer in conjunction with Popov's hyper-stability theory is proposed to calculate the speed and stator resistance independently. The proposed speed observer with parallel stator resistance identification is firstly verified by simulation. Experimental results are included as well to demonstrate the good performance of the proposed observer and estimation algorithms at low speed.

Sensorless interior permanent magnet synchronous motor control with rotational inertia adjustment

Directory of Open Access Journals (Sweden)

Yongle Mao

2016-12-01

Full Text Available Mechanical model is generally required in high dynamic sensorless motor control schemes for zero phase lag estimation of rotor position and speed. However, the rotational inertia uncertainty will cause dynamic estimation errors, eventually resulting in performance deterioration of the sensorless control system. Therefore, this article proposes a high dynamic performance sensorless control strategy with online adjustment of the rotational inertia. Based on a synthetic back electromotive force model, the voltage equation of interior permanent magnet synchronous motor is transformed to that of an equivalent non-salient permanent magnet synchronous motor. Then, an extended nonlinear observer is designed for interior permanent magnet synchronous motor in the stator-fixed coordinate frame, with rotor position, speed and load torque simultaneously estimated. The effect of inaccurate rotational inertia on the estimation of rotor position and speed is investigated, and a novel rotational inertia adjustment approach that employs the gradient descent algorithm is proposed to suppress the dynamic estimation errors. The effectiveness of the proposed control strategy is demonstrated by experimental tests.

Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast.

Science.gov (United States)

Lin, Kang-Wei; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

2016-01-01

In this study, we investigated the transcriptional response to 50 Hz extremely low frequency electromagnetic field (ELF-EMF) and 2.0 GHz radio frequency electromagnetic field (RF-EMF) exposure by Illumina sequencing technology using budding yeast as the model organism. The transcription levels of 28 genes were upregulated and those of four genes were downregulated under ELF-EMF exposure, while the transcription levels of 29 genes were upregulated and those of 24 genes were downregulated under RF-EMF exposure. After validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR), a concordant direction of change both in differential gene expression (DGE) and RT-qPCR was demonstrated for nine genes under ELF-EMF exposure and for 10 genes under RF-EMF exposure. The RT-qPCR results revealed that ELF-EMF and RF-EMF exposure can upregulate the expression of genes involved in glucose transportation and the tricarboxylic acid (TCA) cycle, but not the glycolysis pathway. Energy metabolism is closely related with the cell response to environmental stress including EMF exposure. Our findings may throw light on the mechanism underlying the biological effects of EMF.

WHO's International EMF Project (invited paper)

International Nuclear Information System (INIS)

Repacholi, M.H.

1999-01-01

The International Electromagnetic Fields (EMF) Project assesses health and environmental effects of exposure to static and time varying electric and magnetic fields in the frequency range 0-300 GHz. The Project facilitates a coordinated international response to the concerns about possible health effects of exposure to EMF, assesses the scientific literature, identifies gaps in knowledge needing further research to improve health risk assessments and encourages focused research to fill gaps in knowledge. When the results of this research are published, they will be incorporated into WHO's Environmental Health Criteria monographs where formal health risk assessments are made on exposure to EMF. These monographs provide a database that facilitates the development of internationally acceptable standards for EMF exposure. This paper reviews the International EMF Project activities related to WHO's EMF research requirements and focuses on specific questions raised during the scientific reviews that need to be considered in future epidemiological studies. (author)

Design Methodology of a Brushless IPM Machine for a Zero Speed Injection Based Sensorless Control

OpenAIRE

Godbehere, Jonathan; Wrobel, Rafal; Drury, David; Mellor, Phil

2015-01-01

In this paper a design approach for a sensorless controlled, brushless, interior permanent magnet machine is attained. An initial study based on established electrical machine formulas provides the machine’s basic geometrical sizing. The next design stage combines a particle swarm optimisation (PSO) search routine with a magneto-static finite element (FE) solver to provide a more in depth optimisation. The optimisation system has been formulated to derive alternative machine design variants, ...

Assessment and comparison of total RF-EMF exposure in femtocell and macrocell base station scenarios

OpenAIRE

Aerts, Sam; Plets, David; Verloock, Leen; Martens, Luc; Joseph, Wout

2014-01-01

The indoor coverage of a mobile service can be drastically improved by deployment of an indoor femtocell base station (FBS). However, the impact of its proximity on the total exposure of the human body to radio-frequency (RF) electromagnetic fields (EMFs) is unknown. Using a framework designed for the combination of near-field and far-field exposure, the authors assessed and compared the RF-EMF exposure of a mobile-phone (MP) user that is either connected to an FBS or a conventional macrocell...

Synchronous Switching of Non-Line-Start Permanent Magnet Synchronous Machines between Inverter to Grid Drives

DEFF Research Database (Denmark)

Ni, Ronggang; Xu, Dianguo; Blaabjerg, Frede

2016-01-01

tracking. Furthermore, the method of switching the NLSPMSMs from grid to inverter drives, which is named as backward switching is also proposed. No position sensors are used, and the extended ElectroMotive Force (EMF) based position sensorless control algorithm is adopted during inverter drive. Experiments...

Speed Sensorless Control of Permanent Magnet Synchronous Motors in Mine Electric Locomotive Drive

Directory of Open Access Journals (Sweden)

Yudong LI

2014-04-01

Full Text Available This paper presents a novel sensorless control method of permanent magnet synchronous motors a low speed based on a high-frequency voltage signal injection. The approach superimposes a persistent HF voltage signal into the estimated d-axis to get the rotor position error angle-related signal by detecting the corresponding voltage response and current response. Then the rotor position and motor speed are obtained. Theoretical analysis and simulation results demonstrate that the approach can achieve sensorless control of permanent magnet synchronous motors at zero and low speed, ensure good dynamic and static performances, and achieve effective control when applied to servo system. Finally, a test prototype system which used a digital signal processor and space vector pulse width modulation technology has been developed. Experimental results show that the system has better static, the effectiveness and dynamic performance of the adaptive test signals in a sensorless controlled surface-mounted permanent magnet synchronous machines.

Active-Flux-Based, V/f-with-Stabilizing-Loops Versus Sensorless Vector Control of IPMSM Drives

DEFF Research Database (Denmark)

Moldovan, Ana; Blaabjerg, Frede; Boldea, Ion

2011-01-01

. By this control strategy, a fast dynamic speed response, without steady state error and without speed or current regulators, for all AC machines is obtained. The second control method is a sensorless vector control strategy which also has been implemented and tested, just for comparison.......This paper proposes two control methods for Interior Permanent Magnet Synchronous Motor (IPMSM) Drives. The first one is a V/f control with two stabilizing loops: one loop based on active flux balance for voltage magnitude correction and a second, based on speed error, with voltage phase correction...

Sensorless Control of PM Synchronous Motors and Brushless DC Motors

DEFF Research Database (Denmark)

Montesinos, D.; Galceran, Samuel; Blaabjerg, Frede

2005-01-01

This paper provides a review of the literature addressing sensorless operation methods of PM brushless machines. The methods explained are state-of-the-art of open and closed loop control strategies. The closed loop review includes those methods based on voltage and current measurements, those me...

Sensorless SPMSM Position Estimation Using Position Estimation Error Suppression Control and EKF in Wide Speed Range

Directory of Open Access Journals (Sweden)

Zhanshan Wang

2014-01-01

Full Text Available The control of a high performance alternative current (AC motor drive under sensorless operation needs the accurate estimation of rotor position. In this paper, one method of accurately estimating rotor position by using both motor complex number model based position estimation and position estimation error suppression proportion integral (PI controller is proposed for the sensorless control of the surface permanent magnet synchronous motor (SPMSM. In order to guarantee the accuracy of rotor position estimation in the flux-weakening region, one scheme of identifying the permanent magnet flux of SPMSM by extended Kalman filter (EKF is also proposed, which formed the effective combination method to realize the sensorless control of SPMSM with high accuracy. The simulation results demonstrated the validity and feasibility of the proposed position/speed estimation system.

EMF 9 scenario design (EMF WP 9.4)

International Nuclear Information System (INIS)

Anon.

1989-01-01

This paper describes the specifications of the scenarios selected by the EMF 9 Working Group, which is focusing on North American natural gas markets. The four first-round scenarios include: (1) an upper oil price path, (2) a lower oil price path, (3) a lower resource base, and (4) a higher gas demand due to policies and technologies affecting the electric utility sector. Each scenario represents a combination of market and regulatory environments. For example, the upper oil price scenario combines an upper oil price trend with a reference set of resource and demand conditions and with a pro-competitive regulatory environment. This scenario also serves as a control case for comparing the other scenarios, which specify a change in one of the environments for oil prices, resources, or demand. The regulatory environment has been maintained constant across these first-round scenarios but may be changed depending upon the later recommendations of the regulatory policy and market structure study group. The next section describes the detailed specifications for modelers in simulating the upper oil price scenario. Guidance is offered for energy prices, economic activity, and resource base estimates. The next three sections describe the other three scenarios that involve changes in these inputs from their values in the upper oil price scenario. Special wellhead price assumptions for stand-alone supply models and plans for developing inputs for Canadian models are then discussed. The final section describes the output variables to be reported to the EMF staff for comparing model results

EMF and risk perception

International Nuclear Information System (INIS)

Widemann, P.M.; Schuetz, H.

1995-01-01

There has lately been a greater responsivement in the media as well as the general public to the risk potential of high-frequency electromagnetic fields (EMF). If the discussion continues to gain momentum, this could have grave consequences for companies offering the products or services under attack. The working group Man, Environment, Technology (MUT) at Juelich Research Centre has examined the question of how EMF risks are valuated by the public. The study centered on the following questions: How are EMF risk potentials perceived by the public and what factors influence the public discussion? What future course might the discussion on risks take and what critical events and conditions deserve particular attention? The authors present and discuss the results of this first German study on product-inherent risks. (orig.) [de

EMFs run aground

International Nuclear Information System (INIS)

Raloff, J.

1993-01-01

Presently no one knows whether electromagnetic fields (EMFs) play a role in human cancer or other ailments, though epidemiological studies over the years have suggested that possibility. A study by the Electric Power Research Institute attempted to quantify everything it could about the magnetic environment of a home, identifying not only major sources of magnetic fields, but also their frequencies, strengths, and how they fall off with distance. Sources of a homes magnetic environment include appliances, overhead powerlines, and grounding connections to metallic water pipes. Fields will vary over time, depending on how much current is passing through the electrically conductive sources. Additional contributors to a home's magnetic background may include unusual wiring in the walls, underground power lines, and near-by high voltage transmission lines. This paper summarizes the study results, indicating weak, persistant EMFs may dominate, but small magnetic field associated with ground currents can end up contributing more to the overall EMF background than appliances producing far larger fields which fall off more quickly with distance. 2 figs

Sensorless Control Technology for PMSG base on the Dead-time Compensation voltage

Directory of Open Access Journals (Sweden)

Yang Li-yong

2015-01-01

Full Text Available In order to improve the speed sensorless-control system of PMSG in low speed performance, this paper introduces a novel Dead-time compensation control method .Mathematical model is established according to the Dead-zone of the influence of the voltage source type inverter output voltage. At the same time, the given value of current regulator output voltage has been fixed based on the established model. Then the stator voltage after compensationed is applied to the flux estimation, which improves the performance of flux estimation. Finally, the position and speed of the rotor is estimated based on Back-Electromotive Force, which has Simple algorithm and good robustness. In order to verify the correctness of theoretical analysis, the experiment was done according to the new control method. The results proved the correctness and feasibility of this control method.

Switching EKF technique for rotor and stator resistance estimation in speed sensorless control of IMs

International Nuclear Information System (INIS)

Barut, Murat; Bogosyan, Seta; Gokasan, Metin

2007-01-01

High performance speed sensorless control of induction motors (IMs) calls for estimation and control schemes that offer solutions to parameter uncertainties as well as to difficulties involved with accurate flux/velocity estimation at very low and zero speed. In this study, a new EKF based estimation algorithm is proposed for the solution of both problems and is applied in combination with speed sensorless direct vector control (DVC). The technique is based on the consecutive execution of two EKF algorithms, by switching from one algorithm to another at every n sampling periods. The number of sampling periods, n, is determined based on the desired system performance. The switching EKF approach, thus applied, provides an accurate estimation of an increased number of parameters than would be possible with a single EKF algorithm. The simultaneous and accurate estimation of rotor, R r ' and stator, R s resistances, both in the transient and steady state, is an important challenge in speed sensorless IM control and reported studies achieving satisfactory results are few, if any. With the proposed technique in this study, the sensorless estimation of R r ' and R s is achieved in transient and steady state and in both high and low speed operation while also estimating the unknown load torque, velocity, flux and current components. The performance demonstrated by the simulation results at zero speed, as well as at low and high speed operation is very promising when compared with individual EKF algorithms performing either R r ' or R s estimation or with the few other approaches taken in past studies, which require either signal injection and/or a change of algorithms based on the speed range. The results also motivate utilization of the technique for multiple parameter estimation in a variety of control methods

Portable DMFC system with methanol sensor-less control

Energy Technology Data Exchange (ETDEWEB)

Chen, C.Y.; Liu, D.H.; Huang, C.L.; Chang, C.L. [Institute of Nuclear Energy Research (INER), No. 1000, Wunhua Rd., Jiaan Village, Longtan Township, Taoyuan County 32546 (China)

2007-05-15

This work develops a prototype 20 W portable DMFC by system integration of stack, condenser, methanol sensor-less control and start-up characteristics. The effects of these key components and control schemes on the performance are also discussed. To expedite the use of portable DMFC in electronic applications, the system utilizes a novel methanol sensor-less control method, providing improved fuel efficiency, durability, miniaturization and cost reduction. The operating characteristics of the DMFC stack are applied to control the fuel ejection time and period, enabling the system to continue operating even when the MEAs of the stack are deteriorated. The portable system is also designed with several features including water balance and quick start-up (in 5 min). Notably, the proposed system using methanol sensor-less control with injection of pure methanol can power the DVD player and notebook PC. The system specific energy and energy density following three days of operation are 362 Wh kg{sup -1} and 335 Wh L{sup -1}, respectively, which are better than those of lithium batteries ({proportional_to}150 Wh kg{sup -1} and {proportional_to}250 Wh L{sup -}). This good energy storage feature demonstrates that the portable DMFC is likely to be valuable in computer, communication and consumer electronic (3C) markets. (author)

Electromagnetic fields and the public: EMF standards and estimation of risk

Science.gov (United States)

Grigoriev, Yury

2010-04-01

Mobile communications are a relatively new and additional source of electromagnetic exposure for the population. Standard daily mobile-phone use is known to increase RF-EMF (radiofrequency electromagnetic field) exposure to the brains of users of all ages, whilst mobile-phone base stations, and base station units for cordless phones, can regularly increase the exposures of large numbers of the population to RF-EMF radiation in everyday life. The need to determine appropriate standards stipulating the maximum acceptable short-term and long-term RF-EMF levels encountered by the public, and set such levels as general guidelines, is of great importance in order to help preserve the general public's health and that of the next generation of humanity.

Electromagnetic fields and the public: EMF standards and estimation of risk

International Nuclear Information System (INIS)

Grigoriev, Yury

2010-01-01

Mobile communications are a relatively new and additional source of electromagnetic exposure for the population. Standard daily mobile-phone use is known to increase RF-EMF (radiofrequency electromagnetic field) exposure to the brains of users of all ages, whilst mobile-phone base stations, and base station units for cordless phones, can regularly increase the exposures of large numbers of the population to RF-EMF radiation in everyday life. The need to determine appropriate standards stipulating the maximum acceptable short-term and long-term RF-EMF levels encountered by the public, and set such levels as general guidelines, is of great importance in order to help preserve the general public's health and that of the next generation of humanity.

A Robust Sensorless Direct Torque Control of Induction Motor Based on MRAS and Extended Kalman Filter

Directory of Open Access Journals (Sweden)

Mustapha MESSAOUDI

2008-06-01

Full Text Available In this paper, the classical Direct Torque Control (DTC of Induction Motor (IM using an open loop pure integration suffers from the well-known problems of integration especially in the low speed operation range is detailed. To tackle this problem, the IM variables and parameters estimation is performed using a recursive non-linear observer known as EKF. This observer is used to estimate the stator currents, the rotor flux linkages, the rotor speed and the stator resistance. The main drawback of the EKF in this case is that the load dynamics has to be known which is not usually possible. Therefore, a new method based on the Model Reference Adaptive System (MRAS is used to estimate the rotor speed. The two different nonlinear observers applied to sensorless DTC of IM, are discussed and compared to each other. The rotor speed estimation in DTC technique is affected by parameter variations especially the stator resistance due to temperature particularly at low speeds. Therefore, it is necessary to compensate this parameter variation in sensorless induction motor drives using an online adaptation of the control algorithm by the estimated stator resistance. A simulation work leads to the selected results to support the study findings.

Sensorless AC electric motor control robust advanced design techniques and applications

CERN Document Server

Glumineau, Alain

2015-01-01

This monograph shows the reader how to avoid the burdens of sensor cost, reduced internal physical space, and system complexity in the control of AC motors. Many applications fields—electric vehicles, wind- and wave-energy converters and robotics, among them—will benefit. Sensorless AC Electric Motor Control describes the elimination of physical sensors and their replacement with observers, i.e., software sensors. Robustness is introduced to overcome problems associated with the unavoidable imperfection of knowledge of machine parameters—resistance, inertia, and so on—encountered in real systems. The details of a large number of speed- and/or position-sensorless ideas for different types of permanent-magnet synchronous motors and induction motors are presented along with several novel observer designs for electrical machines. Control strategies are developed using high-order, sliding-mode and quasi-continuous-sliding-mode techniques and two types of observer–controller schemes based on backstepping ...

Determination of Measurement Points in Urban Environments for Assessment of Maximum Exposure to EMF Associated with a Base Station

Directory of Open Access Journals (Sweden)

Agostinho Linhares

2014-01-01

Full Text Available A base station (BS antenna operates in accordance with the established exposure limits if the values of electromagnetic fields (EMF measured in points of maximum exposure are below these limits. In the case of BS in open areas, the maximum exposure to EMF probably occurs in the antenna’s boresight direction, from a few tens to a few hundred meters away. This is not a typical scenery for urban environments. However, in the line of sight (LOS situation, the region of maximum exposure can still be analytically estimated with good results. This paper presents a methodology for the choice of measurement points in urban areas in order to assess compliance with the limits for exposure to EMF.

Sensorless Sliding Mode Vector Control of Induction Motor Drives

OpenAIRE

Gouichiche Abdelmadjid; Boucherit Mohamed Seghir; Safa Ahmed; Messlem Youcef

2012-01-01

In this paper we present the design of sliding mode controllers for sensorless field oriented control of induction motor. In order to improve the performance of controllers, the motor speed is controlled by sliding mode regulator with integral sliding surface. The estimated rotor speed used in speed feedback loop is calculated by an adaptive observer based on MRAS (model reference adaptive system) technique .the validity of the proposed scheme is demonstrated by experimental results.

Evaluation of E.M.F. exposure from medical electrical equipment

Energy Technology Data Exchange (ETDEWEB)

Aniolczyk, H.; Mamrot, P.; Politanski, P. [Nofer Institute of Occupational Medicine, Lodz (Poland)

2006-07-01

he medical electric and electronic equipment, including electro surgical devices, short- and microwave diathermy units, and magnetic resonance imaging (MRI) systems, belong to the most hazardous sources of electromagnetic emissions. The electromagnetic emissions can interfere with emissions from other medical equipment located in the same facility (e.g. operation rooms) thus having impact on their work, but more importantly, they can be dangerous to patients, medical personnel operating them and other persons. In the present project, an assessment of E.M.F. intensity was performed for more than 2 000 electro surgical devices (330 khz, 440 khz and 1.76 MHz frequency ranges), 1 200 diathermy units and 45 MRI 0.2 - 1.5 T systems. E.M.F. exposure of medical staff was assessed based on respective national hygienic standards. The actual exposure levels were found to exceed the admissible values in Poland. The recorded E.M.F. intensities were compared with relevant Who and U E recommendations (e.g. I.C.N.I.R.P. guidelines, 1998, Directive 2004/40/E.C.). The findings revealed that for 18% of the devices examined, the E.M.F. was higher than the E.M.F. intensity values recommended by U E. (authors)

Evaluation of E.M.F. exposure from medical electrical equipment

International Nuclear Information System (INIS)

Aniolczyk, H.; Mamrot, P.; Politanski, P.

2006-01-01

he medical electric and electronic equipment, including electro surgical devices, short- and microwave diathermy units, and magnetic resonance imaging (MRI) systems, belong to the most hazardous sources of electromagnetic emissions. The electromagnetic emissions can interfere with emissions from other medical equipment located in the same facility (e.g. operation rooms) thus having impact on their work, but more importantly, they can be dangerous to patients, medical personnel operating them and other persons. In the present project, an assessment of E.M.F. intensity was performed for more than 2 000 electro surgical devices (330 khz, 440 khz and 1.76 MHz frequency ranges), 1 200 diathermy units and 45 MRI 0.2 - 1.5 T systems. E.M.F. exposure of medical staff was assessed based on respective national hygienic standards. The actual exposure levels were found to exceed the admissible values in Poland. The recorded E.M.F. intensities were compared with relevant Who and U E recommendations (e.g. I.C.N.I.R.P. guidelines, 1998, Directive 2004/40/E.C.). The findings revealed that for 18% of the devices examined, the E.M.F. was higher than the E.M.F. intensity values recommended by U E. (authors)

Magnetic sensorless control of plasma position and shape in a tokamak

International Nuclear Information System (INIS)

Nakamura, K.; Luo, J.R.; Wang, H.Z.

2005-01-01

Magnetic sensorless sensing and control experiments of the plasma horizontal position have been carried out in the superconducting tokamak HT-7. The sensing is made focusing on the ripple frequency component of the power supply with thyristor and directly from them without time integration. There is no drift problem of integrator of magnetic sensors. Two kinds of control experiments were carried out, to keep the position constant and swing the position in a triangular waveform. And magnetic sensorless sensing of plasma shape is discussed. (author)

Combined Flux Observer With Signal Injection Enhancement for Wide Speed Range Sensorless Direct Torque Control of IPMSM Drives

DEFF Research Database (Denmark)

Blaabjerg, Frede; Andreescu, G.-D.; Pitic, C.I.

2008-01-01

voltage-current model with PI compensator for low-speed operations. As speed increases, the observer switches gradually to a PI compensated closed-loop voltage model, which is solely used at high speeds. High-frequency rotating-voltage injection with a single D-module bandpass vector filter and a phase......This paper proposes a motion-sensorless control system using direct torque control with space vector modulation for interior permanent magnet synchronous motor (IPMSM) drives, for wide speed range operation, including standstill. A novel stator flux observer with variable structure uses a combined...

Sensorless Control of Electric Motors with Kalman Filters: Applications to Robotic and Industrial Systems

Directory of Open Access Journals (Sweden)

Gerasimos G. Rigatos

2011-12-01

Full Text Available The paper studies sensorless control for DC and induction motors, using Kalman Filtering techniques. First the case of a DC motor is considered and Kalman Filter-based control is implemented. Next the nonlinear model of a field-oriented induction motor is examined and the motor's angular velocity is estimated by an Extended Kalman Filter which processes measurements of the rotor's angle. Sensorless control of the induction motor is again implemented through feedback of the estimated state vector. Additionally, a state estimation-based control loop is implemented using the Unscented Kalman Filter. Moreover, state estimation-based control is developed for the induction motor model using a nonlinear flatness-based controller and the state estimation that is provided by the Extended Kalman Filter. Unlike field oriented control, in the latter approach there is no assumption about decoupling between the rotor speed dynamics and the magnetic flux dynamics. The efficiency of the Kalman Filter-based control schemes, for both the DC and induction motor models, is evaluated through simulation experiments.

Comparison of sensorless FOC and SVM-DTFC of PMSM for low-speed applications

DEFF Research Database (Denmark)

Basar, M. Sertug; Bech, Michael Møller; Andersen, Torben Ole

2013-01-01

This article presents the performance analysis of Field Oriented Control (FOC) and Space Vector Modulation (SVM) Direct Torque and Flux Control (DTFC) of a Non-Salient Permanent Magnet Synchronous Machine (PMSM) under sensorless control within low speed region. The high-frequency alternating...... with a commercially available PMSM machine. Both controllers show satisfactory sensorless performance. FOC provides smoother and more accurate response while SVM-DTFC has the advantage of faster control....

Comparison of sensorless FOC and SVM-DTFC of PMSM for low-speed applications

DEFF Research Database (Denmark)

Basar, Mehmet Sertug

2016-01-01

This article presents the performance analysis of Field Oriented Control (FOC) and Space Vector Modulation (SVM) Direct Torque and Flux Control (DTFC) of a Non-Salient Permanent Magnet Synchronous Machine (PMSM) under sensorless control within low speed region. The high-frequency alternating...... with a commercially available PMSM machine. Both controllers show satisfactory sensorless performance. FOC provides smoother and more accurate response while SVM-DTFC has the advantage of faster control....

Speed-Sensorless DTC-SVM for Matrix Converter Drives With Simple Nonlinearity Compensation

DEFF Research Database (Denmark)

Lee, Kyo Beum; Blaabjerg, Frede; Yoon, Tae-Woong

2007-01-01

This paper presents a new method to improve the sensorless performance of matrix converter drives using a parameter estimation scheme. To improve low-speed sensorless performance, the nonlinearities of a matrix converter drive such as commutation delays, turn-on and turn-off times of switching de...... compensation method is applied for high performance induction motor drives using a 3-kW matrix converter system without a speed sensor. Experimental results are shown to illustrate the feasibility of the proposed strategy....

Experimental Study of Low Speed Sensorless Control of PMSM Drive Using High Frequency Signal Injection

Directory of Open Access Journals (Sweden)

Jyoti Agrawal

2016-01-01

Full Text Available Conventional techniques for sensorless control of permanent magnet synchronous motor drive (PMSM, which requires information on rotor position, are reviewed, and recent developments in this area are introduced in this paper along with their inherent advantages and drawbacks. The paper presents an improved method for sensorless speed control of PMSM drive with emphasis placed on signal injection method. This signal injection method examines the control performance of sensorless PMSM drive by injecting signal externally and thereby sensing the rotor position. The main objective of this drive system is to have speed control at standstill and low speed regions. Several tests are carried out to demonstrate the ability of proposed models at different operating conditions with the help of simulation results in Matlab/Simulink environment. Simulation results confirm that the proposed sensorless control approach of PMSM can achieve high performance at standstill and low speeds but not at very high speeds. An experimental setup is implemented using a 1HP surface mounted (SM PMSM and DsPICDEM^TM MCHV-2 development board, to check the validity of simulation results.

Novel high efficient speed sensorless controller for maximum power extraction from wind energy conversion systems

International Nuclear Information System (INIS)

Fathabadi, Hassan

2016-01-01

Highlights: • Novel sensorless MPPT technique without drawbacks of other sensor/sensorless methods. • Tracking the actual MPP of WECSs, no tracking the MPP of their wind turbines. • Actually extracting the highest output power from WECSs. • Novel MPPT technique having the MPPT efficiency more than 98.5% for WECSs. • Novel MPPT technique having short convergence time for WECSs. - Abstract: In this study, a novel high accurate sensorless maximum power point tracking (MPPT) method is proposed. The technique tracks the actual maximum power point of a wind energy conversion system (WECS) at which maximum output power is extracted from the system, not the maximum power point of its wind turbine at which maximum mechanical power is obtained from the turbine, so it actually extracts the highest output power from the system. The technique only uses input voltage and current of the converter used in the system, and neither needs any speed sensors (anemometer and tachometer) nor has the drawbacks of other sensor/sensorless based MPPT methods. The technique has been implemented as a MPPT controller by constructing a WECS. Theoretical results, the technique performance, and its advantages are validated by presenting real experimental results. The real static-dynamic response of the MPPT controller is experimentally obtained that verifies the proposed MPPT technique high accurately extracts the highest instant power from wind energy conversion systems with the MPPT efficiency of more than 98.5% and a short convergence time that is only 25 s for the constructed system having a total inertia and friction coefficient of 3.93 kg m 2 and 0.014 N m s, respectively.

Speed-Sensorless DTC-SVM for Matrix Converter Drives With Simple Non-Linearity Compensation

DEFF Research Database (Denmark)

Lee, Kyo-Beum; Blaabjerg, Frede; Yoon, Tae-Woong

2005-01-01

This paper presents a new method to improve sensorless performance of matrix converter drives using a parameter estimation scheme. To improve low-speed sensorless performance, the non-Iinearities of a matrix converter drive such as commutation delays, turn-on and turn-off times of switching devic...... method is applied for high performance induction motor drives using a 3 kW matrix converter system without a speed sensor. Experimental results are shown to illustrate the feasibility of the proposed strategy....

Modeled and perceived RF-EMF exposure from mobile phone base stations in relation to symptom reporting

NARCIS (Netherlands)

Martens, A.L.

2017-01-01

Technological changes have led to a rapid increase in the use of mobile technology. This is coupled with an increase in the number of mobile phone base stations that emit radiofrequency electromagnetic fields (RF-EMF). There are concerns about the potential health effects of this exposure among

Sensorless Control of Electric Motors with Kalman Filters: Applications to Robotic and Industrial Systems

Directory of Open Access Journals (Sweden)

Gerasimos G. Rigatos

2011-12-01

Full Text Available The paper studies sensorless control for DC and induction motors, using Kalman Filtering techniques. First the case of a DC motor is considered and Kalman Filter-based control is implemented. Next the nonlinear model of a field-oriented induction motor is examined and the motor

Assessment and comparison of total RF-EMF exposure in femtocell and macrocell base station scenarios.

Science.gov (United States)

Aerts, Sam; Plets, David; Verloock, Leen; Martens, Luc; Joseph, Wout

2014-12-01

The indoor coverage of a mobile service can be drastically improved by deployment of an indoor femtocell base station (FBS). However, the impact of its proximity on the total exposure of the human body to radio-frequency (RF) electromagnetic fields (EMFs) is unknown. Using a framework designed for the combination of near-field and far-field exposure, the authors assessed and compared the RF-EMF exposure of a mobile-phone (MP) user that is either connected to an FBS or a conventional macrocell base station while in an office environment. It is found that, in average macrocell coverage and MP use-time conditions and for Universal Mobile Telecommunications System technology, the total exposure can be reduced by a factor of 20-40 by using an FBS, mostly due to the significant decrease in the output power of the MP. In general, the framework presented in this study can be used for any exposure scenario, featuring any number of technologies, base stations and/or access points, users and duration. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Reduced Order Extended Luenberger Observer Based Sensorless Vector Control Fed by Matrix Converter with Non-linearity Modeling

DEFF Research Database (Denmark)

Lee, Kyo-Beum; Blaabjerg, Frede

2004-01-01

This paper presents a new sensorless vector control system for high performance induction motor drives fed by a matrix converter with non-linearity compensation. The nonlinear voltage distortion that is caused by commutation delay and on-state voltage drop in switching device is corrected by a new...

High Bandwidth Zero Voltage Injection Method for Sensorless Control of PMSM

DEFF Research Database (Denmark)

Ge, Xie; Lu, Kaiyuan; Kumar, Dwivedi Sanjeet

2014-01-01

High frequency signal injection is widely used in PMSM sensorless control system for low speed operations. The conventional voltage injection method often needs filters to obtain particular harmonic component in order to estimate the rotor position; or it requires several voltage pulses to be inj......High frequency signal injection is widely used in PMSM sensorless control system for low speed operations. The conventional voltage injection method often needs filters to obtain particular harmonic component in order to estimate the rotor position; or it requires several voltage pulses...... in a fast current regulation performance. Injection of zero voltage also minimizes the inverter voltage error effects caused by the dead-time....

Speed Sensorless mixed sensitivity linear parameter variant H_inf control of the induction motor

NARCIS (Netherlands)

Toth, R.; Fodor, D.

2004-01-01

The paper shows the design of a robust control structure for the speed sensorless vector control of the IM, based on the mixed sensitivity (MS) linear parameter variant (LPV) H8 control theory. The controller makes possible the direct control of the flux and speed of the motor with torque adaptation

Novel Observer Scheme of Fuzzy-MRAS Sensorless Speed Control of Induction Motor Drive

Science.gov (United States)

Chekroun, S.; Zerikat, M.; Mechernene, A.; Benharir, N.

2017-01-01

This paper presents a novel approach Fuzzy-MRAS conception for robust accurate tracking of induction motor drive operating in a high-performance drives environment. Of the different methods for sensorless control of induction motor drive the model reference adaptive system (MRAS) finds lot of attention due to its good performance. The analysis of the sensorless vector control system using MRAS is presented and the resistance parameters variations and speed observer using new Fuzzy Self-Tuning adaptive IP Controller is proposed. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. The present approach helps to achieve a good dynamic response, disturbance rejection and low to plant parameter variations of the induction motor. In order to verify the performances of the proposed observer and control algorithms and to test behaviour of the controlled system, numerical simulation is achieved. Simulation results are presented and discussed to shown the validity and the performance of the proposed observer.

Characterization of thermoelectric devices by laser induced Seebeck electromotive force (LIS-EMF) measurement

Energy Technology Data Exchange (ETDEWEB)

Lopez, Luis-David Patino [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Dilhaire, Stefan [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Grauby, Stephane [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Salhi, M Amine [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Ezzahri, Younes [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Claeys, Wilfrid [Universite de Bordeaux 1, Centre de Physique Moleculaire Optique et Hertzienne, 351, cours de la liberation, 33405 Talence (France); Batsale, Jean-Christophe [Laboratoire TREFLE, Esplanade des Arts et Metiers, 33405 Talence Cedex (France)

2005-05-21

An in-depth study related to a new method of characterizing properties in thermoelectrics is proposed in this paper. This technique is appropriate for single or multi-layered thermoelectric devices. A modulated laser beam is used as a heater in order to generate a Seebeck electromotive force (EMF). The laser beam, line shaped, can be focused at any location along the sample surface, allowing spatially resolved measurements. Seebeck EMF measurements, associated with a versatile model based on the thermal quadrupoles method, allow determination of the sample Seebeck EMF profile and identifying of the sample thermal contact resistances, and should be useful for identification of devices and material thermoelectric properties.

Characterization of thermoelectric devices by laser induced Seebeck electromotive force (LIS-EMF) measurement

International Nuclear Information System (INIS)

Lopez, Luis-David Patino; Dilhaire, Stefan; Grauby, Stephane; Salhi, M Amine; Ezzahri, Younes; Claeys, Wilfrid; Batsale, Jean-Christophe

2005-01-01

An in-depth study related to a new method of characterizing properties in thermoelectrics is proposed in this paper. This technique is appropriate for single or multi-layered thermoelectric devices. A modulated laser beam is used as a heater in order to generate a Seebeck electromotive force (EMF). The laser beam, line shaped, can be focused at any location along the sample surface, allowing spatially resolved measurements. Seebeck EMF measurements, associated with a versatile model based on the thermal quadrupoles method, allow determination of the sample Seebeck EMF profile and identifying of the sample thermal contact resistances, and should be useful for identification of devices and material thermoelectric properties

In vivo imaging of human photoreceptor mosaic with wavefront sensorless adaptive optics optical coherence tomography.

Science.gov (United States)

Wong, Kevin S K; Jian, Yifan; Cua, Michelle; Bonora, Stefano; Zawadzki, Robert J; Sarunic, Marinko V

2015-02-01

Wavefront sensorless adaptive optics optical coherence tomography (WSAO-OCT) is a novel imaging technique for in vivo high-resolution depth-resolved imaging that mitigates some of the challenges encountered with the use of sensor-based adaptive optics designs. This technique replaces the Hartmann Shack wavefront sensor used to measure aberrations with a depth-resolved image-driven optimization algorithm, with the metric based on the OCT volumes acquired in real-time. The custom-built ultrahigh-speed GPU processing platform and fast modal optimization algorithm presented in this paper was essential in enabling real-time, in vivo imaging of human retinas with wavefront sensorless AO correction. WSAO-OCT is especially advantageous for developing a clinical high-resolution retinal imaging system as it enables the use of a compact, low-cost and robust lens-based adaptive optics design. In this report, we describe our WSAO-OCT system for imaging the human photoreceptor mosaic in vivo. We validated our system performance by imaging the retina at several eccentricities, and demonstrated the improvement in photoreceptor visibility with WSAO compensation.

Sensorless PV Array Diagnostic Method for Residential PV Systems

DEFF Research Database (Denmark)

Sera, Dezso; Spataru, Sergiu; Mathe, Laszlo

2011-01-01

This work proposes a temperature and irradiance sensorless diagnostic method suitable for small residential PV installations, focusing on detection of partial shadows. The method works by detection of failures in crystalline silicone PV arrays by concomitant monitoring of some of their key...

Chattering-free sliding mode observer for speed sensorless control of PMSM

Directory of Open Access Journals (Sweden)

Mahmoud M. Gaballah

2017-07-01

Full Text Available This article presents a new speed observer based on fuzzy logic for speed sensorless control applications of permanent magnet synchronous motor “PMSM”. The switch function in traditional Sliding Mode Observer “SMO” is replaced by a rule based fuzzy logic system. The proposed observer not only improves the system dynamic performance during disturbances or parameter variations, but also has a high accuracy tracking performance with sufficient chattering reduction. The validity of the new observer corroborated through experimental results using TMS320F28069M Digital Signal Processor “DSP”.

Operation characteristic analysis of a direct methanol fuel cell system using the methanol sensor-less control method

Energy Technology Data Exchange (ETDEWEB)

Chen, C.Y.; Chang, C.L. [Institute of Nuclear Energy Research (INER), Longtan Township, Taoyuan County (China); Sung, C.C. [National Taiwan University (China)

2012-10-15

The application of methanol sensor-less control in a direct methanol fuel cell (DMFC) system eliminates most of the problems encountered when using a methanol sensor and is one of the major solutions currently used in commercial DMFCs. This study focuses on analyzing the effect of the operating characteristics of a DMFC system on its performance under the methanol sensor-less control as developed by Institute of Nuclear Energy Research (INER). Notably, the influence of the dispersion of the methanol injected on the behavior of the system is investigated systematically. In addition, the mechanism of the methanol sensor-less control is investigated by varying factors such as the timing of the injection of methanol, the cathode flow rate, and the anode inlet temperature. These results not only provide insight into the mechanism of methanol sensor-less control but can also aid in the improvement and application of DMFC systems in portable and low-power transportation. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A sensorless method for measuring the point mobility of mechanical structures

Science.gov (United States)

Boulandet, R.; Michau, M.; Herzog, P.; Micheau, P.; Berry, A.

2016-09-01

This paper presents a convenient and cost-effective experimental tool for measuring the mobility characteristics of a mechanical structure. The objective is to demonstrate that the point mobility measurement can be performed using only an electrodynamic inertial exciter. Unlike previous work based on voice coil actuators, no load cell or accelerometer is needed. Instead, it is theoretically shown that the mobility characteristics of the structure can be estimated from variations in the electrical input impedance of the actuator fixed onto it, provided that the electromechanical parameters of the actuator are known. The proof of concept is made experimentally using a cheap commercially available actuator on a simply supported plate, leading to a good dynamic range from 100 Hz to 1 kHz. The methodology to assess the basic parameters of the actuator is also given. Measured data are compared to a standard shaker testing and the strengths and weaknesses of the sensorless mobility measuring device are discussed. It is believed that this sensorless mobility measuring device can be a convenient experimental tool to determine the dynamic characteristics of a wide range of mechanical structures.

Speed sensorless direct torque control of IMs with rotor resistance estimation

International Nuclear Information System (INIS)

Barut, Murat; Bogosyan, Seta; Gokasan, Metin

2005-01-01

Direct torque control (DTC) of induction motors (IMs) requires an accurate knowledge on the amplitude and angular position of the controlled flux in addition to the information related to angular velocity for velocity control applications. However, unknown load torque and uncertainties related to stator/rotor resistances due to operating conditions constitute major challenges for the performance of such systems. The determination of stator resistance can be performed by measurements, but methods must be developed for estimation and identification of rotor resistance and load torque. In this study, an EKF based solution is sought for determination of the rotor resistance and load torque as well as the above mentioned states required for DTC. The EKF algorithm used in conjunction with the speed sensorless DTC is tested under eleven scenarios comprised of various changes made in the velocity reference beside the load torque and rotor resistance values assigned in the model. With no a priori information in the estimated states and parameters, it has been demonstrated that the EKF estimation and sensorless DTC perform quite well in spite of the uncertainties and variations imposed on the system

Sensorless Control of Interior Permanent Magnet Synchronous Motor in Low-Speed Region Using Novel Adaptive Filter

Directory of Open Access Journals (Sweden)

Lisi Tian

2016-12-01

Full Text Available This paper presents a novel position and speed estimation method for low-speed sensorless control of interior permanent-magnet synchronous machines (IPMSMs. The parameter design of the position and speed estimator is based on the sampled current rather than the motor electrical parameters. The proposed method not only simplifies the parameter design, it enables the estimator to work normally even in the condition that the electrical parameters are uncertain or varied. The adaptive filters are adopted to extract the desired high frequency current. The structure and corresponding transfer function are analyzed. To address the shortage of insufficient stop-band attenuation, the structure of the adaptive filter is modified to provide suitable bandwidth and stop-band attenuation simultaneously. The effectiveness of the proposed sensorless control strategy has been verified by simulations and experiments.

An Improved DTC-SVM Method for Sensorless Matrix Converter Drives Using an Overmodulation Strategy and a Simple Nonlinearity Compensation

DEFF Research Database (Denmark)

Lee, Kyo Beum; Blaabjerg, Frede

2007-01-01

In this paper, an improved direct torque control (DTC) method for sensorless matrix converter drives is proposed, which is characterized by minimal torque ripple, unity input power factor, and good sensorless speed-control performance in the low-speed operation, while maintaining constant switchi...

Thermodynamic properties of calcium–bismuth alloys determined by emf measurements

International Nuclear Information System (INIS)

Kim, Hojong; Boysen, Dane A.; Bradwell, David J.; Chung, Brice; Jiang Kai; Tomaszowska, Alina A.; Wang Kangli; Wei Weifeng; Sadoway, Donald R.

2012-01-01

The thermodynamic properties of Ca–Bi alloys were determined by electromotive force (emf) measurements to assess the suitability of Ca–Bi electrodes for electrochemical energy storage applications. Emf was measured at ambient pressure as a function of temperature between 723 K and 1173 K using a Ca(s)|CaF 2 (s)|Ca(in Bi) cell for twenty different Ca–Bi alloys spanning the entire range of composition from x Ca = 0 to 1. Reported are the temperature-independent partial molar entropy and enthalpy of calcium for each Ca–Bi alloy. Also given are the measured activities of calcium, the excess partial molar Gibbs energy of bismuth estimated from the Gibbs–Duhem equation, and the integral change in Gibbs energy for each Ca–Bi alloy at 873 K, 973 K, and 1073 K. Calcium activities at 973 K were found to be nearly constant at a value of a Ca = 1 × 10 −8 over the composition range x Ca = 0.32–0.56, yielding an emf of ∼0.77 V. Above x Ca = 0.62 and coincident with Ca 5 Bi 3 formation, the calcium activity approached unity. The Ca–Bi system was also characterized by differential scanning calorimetry over the entire range of composition. Based upon these data along with the emf measurements, a revised Ca–Bi binary phase diagram is proposed.

Estimating the accuracy of the technique of reconstructing the rotational motion of a satellite based on the measurements of its angular velocity and the magnetic field of the Earth

Science.gov (United States)

Belyaev, M. Yu.; Volkov, O. N.; Monakhov, M. I.; Sazonov, V. V.

2017-09-01

The paper has studied the accuracy of the technique that allows the rotational motion of the Earth artificial satellites (AES) to be reconstructed based on the data of onboard measurements of angular velocity vectors and the strength of the Earth magnetic field (EMF). The technique is based on kinematic equations of the rotational motion of a rigid body. Both types of measurement data collected over some time interval have been processed jointly. The angular velocity measurements have been approximated using convenient formulas, which are substituted into the kinematic differential equations for the quaternion that specifies the transition from the body-fixed coordinate system of a satellite to the inertial coordinate system. Thus obtained equations represent a kinematic model of the rotational motion of a satellite. The solution of these equations, which approximate real motion, has been found by the least-square method from the condition of best fitting between the data of measurements of the EMF strength vector and its calculated values. The accuracy of the technique has been estimated by processing the data obtained from the board of the service module of the International Space Station ( ISS). The reconstruction of station motion using the aforementioned technique has been compared with the telemetry data on the actual motion of the station. The technique has allowed us to reconstruct the station motion in the orbital orientation mode with a maximum error less than 0.6° and the turns with a maximal error of less than 1.2°.

Sensorless Estimation and Nonlinear Control of a Rotational Energy Harvester

Science.gov (United States)

Nunna, Kameswarie; Toh, Tzern T.; Mitcheson, Paul D.; Astolfi, Alessandro

2013-12-01

It is important to perform sensorless monitoring of parameters in energy harvesting devices in order to determine the operating states of the system. However, physical measurements of these parameters is often a challenging task due to the unavailability of access points. This paper presents, as an example application, the design of a nonlinear observer and a nonlinear feedback controller for a rotational energy harvester. A dynamic model of a rotational energy harvester with its power electronic interface is derived and validated. This model is then used to design a nonlinear observer and a nonlinear feedback controller which yield a sensorless closed-loop system. The observer estimates the mechancial quantities from the measured electrical quantities while the control law sustains power generation across a range of source rotation speeds. The proposed scheme is assessed through simulations and experiments.

Sensorless Suitability Analysis of Hybrid PM Machines for Electric Vehicles

DEFF Research Database (Denmark)

Matzen, Torben Nørregaard; Rasmussen, Peter Omand

2009-01-01

Electrical machines for traction in electric vehicles are an essential component which attract attention with respect to machine design and control as a part of the emerging renewable industry. For the hybrid electric machine to replace the familiar behaviour of the combustion engine torque......, control seems necessary to implement. For hybrid permanent magnet (PM) machines torque control in an indirect fashion using dq-current control is frequently done. This approach requires knowledge about the machine shaft position which may be obtained sensorless. In this article a method based on accurate...

Minimum-Voltage Vector Injection Method for Sensorless Control of PMSM for Low-Speed Operations

DEFF Research Database (Denmark)

Xie, Ge; Lu, Kaiyuan; Kumar, Dwivedi Sanjeet

2016-01-01

In this paper, a simple signal injection method is proposed for sensorless control of PMSM at low speed, which ideally requires one voltage vector only for position estimation. The proposed method is easy to implement resulting in low computation burden. No filters are needed for extracting...... may also be further developed to inject two opposite voltage vectors to reduce the effects of inverter voltage error on the position estimation accuracy. The effectiveness of the proposed method is demonstrated by comparing with other sensorless control method. Theoretical analysis and experimental...

Hybrid I-f starting and observer-based Ssnsorless control of single-phase BLDC-PM motor drives

DEFF Research Database (Denmark)

Iepure, Liviu Ioan; Boldea, Ion; Blaabjerg, Frede

2012-01-01

A motion sensorless control for single-phase permanent magnet brushless dc motor based on an I-f starting sequence and a real-time permanent magnet flux estimation is proposed here. The special calculation for extracting the position and speed used here implies the generating of an orthogonal flux...... system, the atan2 trigonometric function, and a phase-locked loop observer. The influence of the permanent magnet flux harmonic content is presented by analytical expressions and digital simulations. The proposed sensorless control is validated by complete experimental results on a commercial small high......-speed blower-motor (40 W, 10 krpm, 12 Vdc)....

A comparative study between three sensorless control strategies for PMSG in wind energy conversion system

Energy Technology Data Exchange (ETDEWEB)

Brahmi, Jemaa; Krichen, Lotfi; Ouali, Abderrazak [Advanced Control and Energy Management Research Unit ENIS, Department of Electrical Engineering, University of Sfax, 3038 Sfax (Tunisia)

2009-09-15

This paper presents a comparative study of sliding mode, artificial neural network and model reference adaptive speed observers for a speed sensorless permanent magnet synchronous generator (PMSG) in wind energy conversion system (WECS). Wind velocity and position sensorless operating methods for wind generation system using observer are proposed only by measuring phase voltages and currents. Maximum wind energy extraction is achieved by running the wind turbine generator in variable-speed mode. In addition the three speed observers are compared to verify the robustness against parameter variations. (author)

Analysis, design and implementation of sensorless V/f control in a ...

Indian Academy of Sciences (India)

SOURABH PAITANDI

Keywords. Surface-mounted PMSM; V/f control; sensorless control; stabilisation of PMSM; efficiency optimisation. ..... The power balance equation can be written as, pe ¼ Pe ю .... loading the actual speed falls for a very short transient period.

Proposition for sensorless self-excitation by a piezoelectric device

Science.gov (United States)

Tanaka, Y.; Kokubun, Y.; Yabuno, H.

2018-04-01

In this paper, we propose a method to realize self-excitation in an oscillator actuated by a piezoelectric device without a sensor. In general, the positive feedback associated with the oscillator velocity causes the self-excitation. Instead of measuring the velocity with a sensor, we utilize the electro-mechanical coupling effect in the oscillator and piezoelectric device. We drive the piezoelectric device with a current proportional to the linear combination of the voltage across the terminals of the piezoelectric device and its differential voltage signal. Then, the oscillator with the piezoelectric device behaves like a third-order system, which has three eigenvalues. The self-excitation can be realized because appropriate feedback gains can set two of the eigenvalues to be conjugate complex roots with a positive real part and the other eigenvalue to be a negative real root. To confirm the validity of the proposed method, we experimentally demonstrated the sensorless self-excitation and, as an application example, carried out mass sensing in a sensorless self-excited macrocantilever.

Influence of parameters detuning on induction motor NFO shaft-sensorless scheme

Directory of Open Access Journals (Sweden)

KULIC, F.

2010-11-01

Full Text Available In this paper, the parameter sensitivity analysis of shaft-sensorless induction motor drive with natural field orientation (NFO scheme is performed. NFO scheme calculates rotor flux position using the rotor flux vector reference only, does not require significant processor power and therefore it is suitable for low cost shaft sensorless drives. This concept also eliminates the need for sensitive stator voltage vector integration and it is usable in low rotor speed range. However, low speeds are coupled with low stator voltage amplitudes, which inflate the NFO scheme sensitivity to an error in stator resistance parameter. Similar problems can also take place if mutual inductance parameter is detuned, but this time in whole speed range. This paper investigates the influence of each parameter error on the NFO control steady state characteristics and dynamic performance.

Sensorless control of interior permanent-magnet synchronous motors with compressor load

DEFF Research Database (Denmark)

Huang, Shoudao; Gao, Jian; Xiao, Lei

2013-01-01

This paper analyzes the mathematical model of the interior permanent-magnet synchronous motors (IPMSM). Through the mathematical deformation, the paper proposes the new sensorless method based on sliding mode observer for a IPMSM. The model is only associated with the q-axis inductance, and without...... the d-axis inductance. Dual filter is set series to extract the electromotive force information, and then filter phase shift is measured real-time at different speeds for angle compensation. An I-F strategy is adopted to start the IPMSM with compressor load. Finally, the experimental proves the validity...

Improved state observers for sensorless single phase BLDC-PM motor drives

DEFF Research Database (Denmark)

Lepure, Liviu L.; Boldea, Ion; Andreescu, Gheorghe Daniel

2010-01-01

Two methods of extracting the rotor position and speed for a sensorless single phase BLDC-PM motor drive by measuring only the phase current are presented here. Both methods are based on a generated orthogonal flux system. The first method extracts the position information by using the tan−1...... function and then an improved observer is created by adding a 4th order harmonic term in the estimated position, while the second method uses a phase locked loop structure. The proposed state observers are detailed using simulation results and then validated by experimental results....

Sensorless control method of instant-heating module for a bidet

Energy Technology Data Exchange (ETDEWEB)

Jung, D. [Korea Polytechnic Univ. (Korea, Republic of). Dept. of Electronics Engineering

2006-07-01

The three types of temperature control schemes for a bidet system are the mechanical type where both hot water and cold water are supplied to bidet system and users control the outlet water; hot water-tank type where temperature in outlet water is slowly controlled in the hot water tanks; and, instant-heating module type where temperature in outlet water is controlled by a ceramic heater and switching device. All types have advantages and disadvantages. This paper addressed the need for a sensor-less control scheme for an instant-heating module for a bidet, which can control water temperature effectively without using the flow-velocity sensor of the flowing water. The sensor-less control scheme is meant to reduce costs and improve reliability. In this study, a steady state model and simplified model of instant-heating module was developed. An estimation algorithm for the value of flow-velocity of water was also proposed. Experimental work performed under various operating conditions was presented to demonstrate the validity of the proposed sensor-less control scheme. The velocity of the flowing water was estimated by monitoring the changes in outlet water temperature and by analyzing the results against information of inlet water temperature and the switching command for Triac bridge circuit. This information can be readily acquired during the cleaning operation of a bidet system. It was concluded that the proposed method can be easily integrated with existing low-cost control schemes. Future work will focus on mass production of the system, such as developing reliable automatic tuning algorithm to apply the proposed scheme for commercial use. 3 refs., 1 tab., 6 figs.

Sensorless Control of Permanent Magnet Synchronous Machines

DEFF Research Database (Denmark)

Matzen, Torben N.

Permanent magnet machines, with either surface mounted or embedded magnets on the rotor, are becoming more common due to the key advantages of higher energy conversion efficiency and higher torque density compared to the classical induction machine. Besides energy efficiency the permanent magnet...... the synchronous machine requires knowledge of the rotor shaft position due to the synchronous and undamped nature of the machine. The rotor position may be measured using a mechanical sensor, but the sensor reduces reliability and adds cost to the system and for this reason sensorless control methods started...... are dependent on the phase currents and rotor position. Based on the flux linkages the differential inductances are determined and used to establish the inductance saliency in terms of ratio and orientation. The orientation and its dependence on the current and rotor position are used to analyse the behaviour...

New bimetallic EMF cell shows promise in direct energy conversion

Science.gov (United States)

Hesson, J. C.; Shimotake, H.

1968-01-01

Concentration cell, based upon a thermally regenerative cell principle, produces electrical energy from any large heat source. This experimental bimetallic EMF cell uses a sodium-bismuth alloy cathode and a pure liquid sodium anode. The cell exhibits reliability, corrosion resistance, and high current density performance.

Relation of Giant Thermo-EMF, Magnetothermo-EMF, Magnetoresistance, and Magnetization to Magnetic Impurity States in Manganites Nd(1- x)Sr x MnO3 and Sm(1- x)Sr x MnO3

Science.gov (United States)

Koroleva, L. I.; Batashev, I. K.; Morozov, A. S.; Balbashov, A. M.; Szymczak, H.; Slawska-Waniew, A.

2018-02-01

Thermo-EMF, magnetothermo-EMF, magnetoresistance, and magnetization of single-crystal samples of Nd(1- x)Sr x MnO3 and Sm(1- x)Sr x MnO3 with 0 ≤ x ≤ 0.3 have been studied experimentally. A sharp increase in the thermo-EMF and giant magnetothermo-EMF and magnetoresistance has been observed near the Curie point T C in compounds with 0.15 ≤ x ≤ 0.3. At the same time, no peculiarities have been found in compositions with x = 0. Since compounds with x > 0 consist of ferromagnetic clusters of the ferron type that reside in an antiferromagnetic A-type matrix, this means that the sharp increase in the thermo-EMF near T C is caused by ferrons. Indeed, the disappearance of ferrons due to a magnetic field or heating above T C leads to an abrupt decrease in the thermo-EMF. Therefore, thermo-EMF in alloyed magnetic semiconductors has been determined by the impurity concentration and the sample volume.

Two-way portable radios: monitoring exposure to EMF

International Nuclear Information System (INIS)

Aguiar Campos, Maria C.

2008-01-01

Full text: Hand-held two-way portable radios, also known as push-to-talk radios (PTT), radiate intense electromagnetic fields (EMF). Increasingly used for communications inside buildings, these devices should not be neglected as EMF sources in workplace environments. In contrast to mobile-phones, push-to-talk radios usually operate in a lower frequency range (450 < f < 470 MHz), where the reference levels, established by ICNIRP for human exposure, are more restrictive. The intrinsic hazard potential associated to these devices has motivated this assessment of occupational exposure to EMF. In spite of relatively low power levels, usually no more than a few watts, and the intermittency of transmissions, push-to-talk radios are operated close to the body, therefore exposure takes place in the near-field region. Measurements of electromagnetic field intensities were carried out for two push-to-talk models, operating at power levels of 2 W and 5 W, with a broad-band field monitor, EMR-300 (W and G), coupled to an E-field triaxial probe (type 8.0). Intensities were measured at various points surrounding the transmitter, to assess exposure levels of other workers sitting nearby during communications. Results show significant electric field intensities at points less than 10 cm away from the source. A personal monitor with triaxial E and H-field shaped probes, RadMan XT (Narda), was used as a dosimeter by workers operating both radio models, during 8 hours. This device measures E and H-field intensities and stores these values as a percentage of ICNIRP occupational limits, in a data logger. Results of both kind of measurements show that intense EMF are emitted during transmissions. Therefore, workers should be informed about possible EMF hazards and trained to properly operate these transmitters, in order to minimize exposure risks. (author)

A Rotor Flux and Speed Observer for Sensorless Single-Phase Induction Motor Applications

Directory of Open Access Journals (Sweden)

Massimo Caruso

2012-01-01

Full Text Available It is usual to find single-phase induction motor (SPIM in several house, office, shopping, farm, and industry applications, which are become each time more sophisticated and requiring the development of efficient alternatives to improve the operational performance of this machine. Although the rotor flux and rotational speed are essential variables in order to optimize the operation of a SPIM, the use of conventional sensors to measure them is not a viable option. Thus, the adoption of sensorless strategies is the more reasonable proposal for these cases. This paper presents a rotor flux and rotational speed observer for sensorless applications involving SPIMs. Computer simulations and the experimental results are used to verify the performance of the proposed observer.

Measuring electromagnetic fields (EMF) around wind turbines in Canada: is there a human health concern?

OpenAIRE

McCallum, Lindsay C; Whitfield Aslund, Melissa L; Knopper, Loren D; Ferguson, Glenn M; Ollson, Christopher A

2014-01-01

Background The past five years has seen considerable expansion of wind power generation in Ontario, Canada. Most recently worries about exposure to electromagnetic fields (EMF) from wind turbines, and associated electrical transmission, has been raised at public meetings and legal proceedings. These fears have not been based on any actual measurements of EMF exposure surrounding existing projects but appear to follow from worries from internet sources and misunderstanding of the science. Meth...

EVALUATION OF EMF EXPOSURE OF MOBILE PHONES ON HUMAN HEAD

Directory of Open Access Journals (Sweden)

N. I. Vtornikova

2017-01-01

Full Text Available Introduction. Mobile phones are worldwide spread nowadays. Smartphones penetration is growing year after year. Numerous studies indicate the negative effect of EMF exposure of these devices on humans. Therefore, it is important to study the peculiarities of their influence on the target organ-the brain. It is important for solving this problem to find out the real situation of the distribution of energy flux density (EFD of EMF exposure near the front panel of the apparatus.The aim of the study is to determine and compare EMF exposure from smartphones and classic mobile phones on human head.Material and methods. The original method patented in the Russian Federation was used in this study. The used original measuring setup is also patented, developed and assembled by the authors of the study. The object of the study was classical mobile phones and smartphones widespread at the time of work.Results. We got the graphic of matrices of distribution of energy flux density (EFD of EMF exposure in the plane against the front panel of 10 apparatus corresponding to the topography of a human head. The study revealed peculiarities of this distribution in smartphones and the classic mobile phones and got the values of energy flux density (EFD of EMF exposure in the investigated devices acting primarily on the brain.Conclusions. The design of smartphones and mobile phones determines the overall picture of distribution of EFD of EMF exposure in the plane against the front panel for devices of a particular type. This picture must be taken into account when planning epidemiological and experimental studies to obtain comparable results. Progress in the development of mobile communication technologies has led to an increase in the electromagnetic load on users of modern devices.

High-performance sensorless nonlinear power control of a flywheel energy storage system

International Nuclear Information System (INIS)

Amodeo, S.J.; Chiacchiarini, H.G.; Solsona, J.A.; Busada, C.A.

2009-01-01

The flywheel energy storage systems (FESS) can be used to store and release energy in high power pulsed systems. Based on the use of a homopolar synchronous machine in a FESS, a high performance model-based power flow control law is developed using the feedback linearization methodology. This law is based on the voltage space vector reference frame machine model. To reduce the magnetic losses, a pulse amplitude modulation driver for the armature is more adequate. The restrictions in amplitude and phase imposed by the driver are also included. A full order Luenberger observer for the torque angle and rotor speed is developed to implement a sensorless control strategy. Simulation results are presented to illustrate the performance.

Very low speed performance of active flux based sensorless control: interior permanent magnet synchronous motor vector control versus direct torque and flux control

DEFF Research Database (Denmark)

Paicu, M. C.; Boldea, I.; Andreescu, G. D.

2009-01-01

This study is focused on very low speed performance comparison between two sensorless control systems based on the novel ‘active flux' concept, that is, the current/voltage vector control versus direct torque and flux control (DTFC) for interior permanent magnet synchronous motor (IPMSM) drives...... with space vector modulation (SVM), without signal injection. The active flux, defined as the flux that multiplies iq current in the dq-model torque expression of all ac machines, is easily obtained from the stator-flux vector and has the rotor position orientation. Therefore notable simplification...

A polynomial-time algorithm to design push plans for sensorless parts sorting

NARCIS (Netherlands)

Berg, de M.; Goaoc, X.; van der Stappen, A.F.

2005-01-01

We consider the efficient computation of sequences of push actions that simultaneously orient two different polygons. Our motivation for studying this problem comes from the observation that appropriately oriented parts admit simple sensorless sorting. We study the sorting of two polygonal parts by

Use of C. Elegans as a model organism for sensing the effects of ELF-EMFs

Energy Technology Data Exchange (ETDEWEB)

Lacchini, A H; Everington, M L; Augousti, A T; Walker, A J [School of Life Sciences, Kingston University London (United Kingdom)

2007-07-15

For the past two decades, there have been concerns and controversy about the effects on human health of the increased exposure to extremely-low-frequency (ELF) electromagnetic fields (EMFs) resulting from electrification, in both residential and industrial settings. Several epidemiological studies have implicated ELF-EMFs averaging 0.4 {mu}mUTesla (T) or more in increased risk of cancer, especially childhood leukaemia [1,2]; there have also been many reports demonstrating effects of power-frequency EMFs on cells [outlined in 1,3]. Unfortunately, however, the precise mechanisms by which ELF-EMFs exert biological effects have proven difficult to define and results of various studies have often been hard to reproduce [1]. We believe that C. elegans offers an exciting opportunity to elucidate the effects of power-frequency EMFs on cell signalling pathways within the whole organism and are therefore investigating the effects of ELF-EMF exposure on MAPK signalling in intact worms and fertilized embryos. Through taking a targeted approach to studying the effects of ELF-EMF's on MAPK signalling in C. elegans we aim to gather data that is physiologically relevant. Presently, this research is at a preliminary stage of preparation, and more detailed results on the exposure of Caenorhabditis elegans to ELF-EMF radiation will be presented at the conference itself.

Artificial neural networks to estimate the EMF ELF on car travelling near power transmission line

Energy Technology Data Exchange (ETDEWEB)

Al-Sayegh, O.A.; Qabazard, A.M. [Kuwait Inst. for Scientific Research, Safat (Kuwait). advanced Systems Division of Environment and Urban

2007-07-01

An artificial neural network (ANN) was developed to determine the electromagnetic field (EMF) and extremely low frequency (ELF) intensity on a vehicle body at different distances from a high tension power line and at varying power loads. EMF radiated emissions from ELF source power transmission lines can produce interference in the electric components in vehicles traveling at variable speed near the power lines. The passengers in the vehicle may also experience EMF-related health problems. Although EMF has been recently categorized as a new form of pollution, the situation has been largely ignored by the industry. Typically, electromagnetic fields at different frequencies show the fastest growing environmental influences. All populations are now exposed to varying degrees of EMF and the levels will continue to increase as technology advances. The purpose of this work was to promote discussion and help find design solutions to manufacture a new device for measuring the EMF at variable speed. In this study, a set of near field measurements outside the vehicle were used to train ANN. Estimations of the EMF ELF for various distances from the high tension power line were presented. It was determined that the most important factors affecting the electric field model include exposure conditions; size, shape and position of the exposed body in the field; and, surface charge density. The EMF ELF was found to increase near sagging areas of the overhead power transmission line. The EMF ELF was found to be proportional to the total amps flowing through the line at the time of measurement. 14 refs., 3 figs.

Simulation study of induced EMFs and the suppression during SST-1 start-up

Energy Technology Data Exchange (ETDEWEB)

Jain, V., E-mail: vishal@ipr.res.in; Sharma, D.; Vardhrajulu, A.; Gupta, C.N.; Srinivasan, R.; Daniel, R.

2015-11-15

Highlights: • Induced EMFs study in PF coils during SST-1 start up using MATlab simulink. • Integration of wave shaping network to generate practical OT current profile. • This study would protect coil insulation with identifying RC circulating network. • Study of MOV technique for circulation of current through RC. - Abstract: Steady State Superconducting Tokamak (SST-1) comprises of various copper and superconducting coils for generating magnetic field for initiation, providing equilibrium and shaping of plasma in tokamak. In this paper, an attempt is made to study the induced EMF in superconducting poloidal field coils (PF coils) due to fast ramp down of current in ohmic transformer copper coils (OT coils) for SST-1 plasma initiation. The fast ramp down of current, from few kA to zero amperes in just 50–100 ms in OT coils, is required to achieve plasma breakdown and ramp up of plasma current in tokamak. However, it induces nearly 5 kV EMF in one of the SST-1 PF coils that can damage the coil insulation and also bias negatively the electronic switching of power supply. It is necessary to maintain induced EMF below 1 kV in all PF coils for safe operation of SST-1. The induced EMF up to 1 kV can be clamped without any need of protection and circulating current. If the induced EMF is in excess of 1 kV, then it has to allow the circulation of current through RC network for coil protection from overvoltage. These circulating currents in PF coils will affect the shaping of plasma. In this paper, the induced EMF in PF coils are simulated using MATlab simulink for a typical SST-1 current profile of OT coils. Further, this simulation study is used to design the protection system for PF coils. In this paper, the worst-case induced EMF scenario is considered by excluding the effect of passive elements like vacuum vessel and cryostat on mutual coupling parameters. However, the implementation of the EMF suppression scheme need more elaborated study with considering

Effects of EMF Emissions from Cables and Junction Boxes on Marine Species

Energy Technology Data Exchange (ETDEWEB)

Dhanak, Manhar [Florida Atlantic Univ., Boca Raton, FL (United States); Spieler, Richard [Nova Southeastern Univ., Fort Lauderdale, FL (United States); Kilfoyle, Kirk [Nova Southeastern Univ., Fort Lauderdale, FL (United States); Jermain, Robert F. [Nova Southeastern Univ., Fort Lauderdale, FL (United States); Frankenfield, John [Florida Atlantic Univ., Boca Raton, FL (United States); Ravenna, Shirley [Florida Atlantic Univ., Boca Raton, FL (United States); Dibiasio, Christopher [Florida Atlantic Univ., Boca Raton, FL (United States); Coulson, Robert [Florida Atlantic Univ., Boca Raton, FL (United States); Henderson, Ed [Florida Atlantic Univ., Boca Raton, FL (United States); Venezia, William [Naval Surface Warfare Center (NSWC), Carderock Division (United States)

2016-09-29

Studies have shown that diverse aquatic species are electrosensitive. Many fishes, and marine mammals, can either detect, navigate by, or are affected by electromagnetic fields (EMF) with various sensitivities, and their behavior may be impacted by unnatural EMF emissions in the water column. Sharks, rays and skates are known to have the highest sensitivity to electric fields. Electric field emissions in the range 0.5–100 micro volt/m appear to attract them, and emissions over 100 micro volt/m to repulse them. A marine hydrokinetic MHK device will have multiple components and associated multiple submarine cables on the seafloor and running through the water column and would potentially increase the level of EMF emissions to which the marine species at the site may be exposed to. There are therefore concerns amongst stakeholders that EMF emissions associated with MHK devices and their components may act as barriers to species migration, cause disorientation, change community compositions and ecosystems, and that they may attract sharks, leading to a local increase in the risk of shark attacks. However, field data to validate and model potential relationships between observed responses and the EMF emissions in situ are sparse. A program of experimental field surveys were conducted off the coast of South Florida, USA to characterize the electromagnetic field (EMF) emissions in the water column from a submarine cable, and to monitor for responses of local aquatic species. The field surveys were conducted at the South Florida Ocean Measurement Facility (SFOMF) off Fort Lauderdale, which is a cabled offshore in-water navy range. It consists of multiple active submarine power cables and a number of junction boxes, with the capability to transmit AC/DC power at a range of strength and frequencies. The site includes significant marine life activities and community structure, including highly mobile species, such as sharks, stingrays, mammals and turtles. SFOMF therefore

Sensorless Speed Control including zero speed of Non Salient PM Synchronous Drives

DEFF Research Database (Denmark)

Rasmussen, Henrik

This paper presents a position sensorless drive of non salient pole PM synchronous motors for all speeds including zero speed. Using adaptive Lyapunov design a new approach for the design of an observer is developed. The resulting scheme leads to a nonlinear full order observer for the motor states...

Sensorless Speed Control including zero speed of Non Salient PM Synchronous Drives

DEFF Research Database (Denmark)

Rasmussen, Henrik

2005-01-01

This paper presents a position sensorless drive of non salient pole PM synchronous motors for all speeds including zero speed. Using adaptive Lyapunov design a new approach for the design of an observer is developed. The resulting scheme leads to a nonlinear full order observer for the motor states...

Sensorless speed Control including Zero Speed on Non Salient PM Synchronous Drives

DEFF Research Database (Denmark)

Rasmussen, Henrik

2006-01-01

This paper presents a position sensorless drive of non salient pole PM synchronous motors for all speeds including zero speed. Using adaptive Lyapunov design a new approach for the design of an observer is developed. The resulting scheme leads to a nonlinear full order observer for the motor states...

Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF: A systematic review of identifying criteria

Directory of Open Access Journals (Sweden)

Baliatsas Christos

2012-08-01

Full Text Available Abstract Background Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF remains a complex and unclear phenomenon, often characterized by the report of various, non-specific physical symptoms (NSPS when an EMF source is present or perceived by the individual. The lack of validated criteria for defining and assessing IEI-EMF affects the quality of the relevant research, hindering not only the comparison or integration of study findings, but also the identification and management of patients by health care providers. The objective of this review was to evaluate and summarize the criteria that previous studies employed to identify IEI-EMF participants. Methods An extensive literature search was performed for studies published up to June 2011. We searched EMBASE, Medline, Psychinfo, Scopus and Web of Science. Additionally, citation analyses were performed for key papers, reference sections of relevant papers were searched, conference proceedings were examined and a literature database held by the Mobile Phones Research Unit of King’s College London was reviewed. Results Sixty-three studies were included. “Hypersensitivity to EMF” was the most frequently used descriptive term. Despite heterogeneity, the criteria predominantly used to identify IEI-EMF individuals were: 1. Self-report of being (hypersensitive to EMF. 2. Attribution of NSPS to at least one EMF source. 3. Absence of medical or psychiatric/psychological disorder capable of accounting for these symptoms 4. Symptoms should occur soon (up to 24 hours after the individual perceives an exposure source or exposed area. (Hypersensitivity to EMF was either generalized (attribution to various EMF sources or source-specific. Experimental studies used a larger number of criteria than those of observational design and performed more frequently a medical examination or interview as prerequisite for inclusion. Conclusions Considerable heterogeneity exists in the

Sensorless-adaptive DTC of double star induction motor

International Nuclear Information System (INIS)

Khedher, Adel; Faouzi Mimouni, Mohamed

2010-01-01

This paper presents a study of extension of the Direct Torque Control approach (DTC) developed by Takahashi for a double star induction motor (DSIM) and a new DTC-Space vector modulation (DTC-SVM) strategy around two dead-beat controllers. The suggested control is performed by using a sliding mode stator flux observer (SMSFO). This last allow to estimating the mechanical speed and the electromagnetic torque. To adapt in real time the rotor resistance variations according to temperature effect, the sensorless method is performed by using an adaptive algorithm which is based on the Lyapunov stability theory. Moreover, this paper treats the study of the system stability under the new suggested control. The simulation results for various scenarios operation show the high performances of the proposed control in terms of piloting effectiveness, precision, rapidity and stability for the high powers DSIM operating at variable speeds.

monIT: A Portuguese Risk Communication Project on EMF

International Nuclear Information System (INIS)

Oliveira, Carla; Sebastiao, Daniel; Carpinteiro, Goncalo; Fernandes, Carlos A.; Correia, Luis M.

2006-01-01

The monIT project is a risk communication programme, aiming at providing information on exposure to electromagnetic fields (EMF) from mobile communication systems in Portugal. monIT's website, www.lxlit.pt/monit, is the main interface for dissemination of information. Besides including relevant information about EMF for both the general public and the technical community, this website provides results from extensive measurement campaigns performed all over Portugal during the last three years. This paper presents the project's structure and activities, practical results achieved and ends with some conclusions and action lines for future work. (author)

Electric fields in accelerating conductors: measurement of the EMF in rotationally accelerating coils

Energy Technology Data Exchange (ETDEWEB)

Moorhead, G.F.; Opat, G.I.

1996-06-06

The acceleration of an electric conductor is predicted to produce an electric filed proportional to m/q where `m`is the free mass and `q` the charge of the carriers of the electric current. In certain configurations this leads to a measurable electromagnetic field (EMF). In this paper is reported a measurement of the EMF induced by rotationally accelerating coils of aluminium and copper wire. The measured EMFs are found to agree with the theoretical predictions to within the error estimates. 23 refs., 1 tab., 4 figs.

Electric fields in accelerating conductors: measurement of the EMF in rotationally accelerating coils

International Nuclear Information System (INIS)

Moorhead, G.F.; Opat, G.I.

1996-01-01

The acceleration of an electric conductor is predicted to produce an electric filed proportional to m/q where 'm'is the free mass and 'q' the charge of the carriers of the electric current. In certain configurations this leads to a measurable electromagnetic field (EMF). In this paper is reported a measurement of the EMF induced by rotationally accelerating coils of aluminium and copper wire. The measured EMFs are found to agree with the theoretical predictions to within the error estimates. 23 refs., 1 tab., 4 figs

Design and strength evaluation of structural joint made by electro-magnetic forming (EMF)

International Nuclear Information System (INIS)

Park, Young-Bae; Oh, Soo-Ik; Kim, Heon-Young

2004-01-01

Recently, weight reduction of vehicles has been of great interest, and consequently, the use of low-density materials in the automotive industry is increasing every year. Materials should not be substituted such a way that material of component parts is simply changed because there is a problem in achieving stiffness and strength. To achieve these requirements, the automobile should be redesigned totally. Aluminum spaceframe is rapidly being adopted as a body structure for accommodating lightness, stiffness and strength requirement. In aluminum spaceframe manufacturing, it is often required to join aluminum tube. But there are few suitable methods for joining aluminum tube, so that much interest has been focused on testing suitable joining methods. Joining by electromagnetic forming(EMF) can be useful method in joining aluminum tube, which offers some advantages compared with the conventional joining method. In this paper, joining by EMF was investigated as a pre-study for applying an automotive spaceframe. Finite element simulations and strength tests were performed to analyze the influence of geometric parameters on joint strength. Based on these results, configurations of axial joint and torque joint were suggested and guidelines for designing EMF joint were established

Recommendations for Guidelines for EMF Personal Exposure Measurements, Rapid Project #4

Energy Technology Data Exchange (ETDEWEB)

T. Dan Bracken, Inc.

1997-08-01

The purpose of developing guidelines for electric and magnetic field (EMF) personal exposure measurements (lF'EM) is to ensure reliable and comparable data across I?EM studies. Study techniques may vary due to different populations or objectives, but the resulting data should be consistently reported and comparable, to the extent possible. Any guideline must allow creativity by the research-oriented investigator and provide specific guidance to industrial hygienists or other results-oriented investigators, requiring a standard protocol. Recognizing measurement studies with different purposes is an important aspect of these recommendations. The guidelines presented here intend to produce comparable data across studies while remaining flexible. The recommendations for designing and implementing an EMF PEM program describe a three-stage process. The first step is to clearly state the purpose of the PEM program. The next stage addresses the fundamental elements of an EMF PEM study, including an assessment of the scientific and organizational resources that will be required. This process is codified in a written study plan. These stages are described in 1 Section 5 of this report. The third stage of a PEM study involves the design, implementation and documentation of specific procedures and protocols fo~ sampling strategies, selection of measurement parameters; instrumentation, measurement and data collection, data management, data analysis, quality assurance, uncertainty evaluation, and archiving the study methods and results. The methods for designing these elements of an EMF PEM study are described in Section 6: Specific Guidelines for EMF I?EM Study Design.

Accurate torque-sensorless control approach for interior permanent-magnet synchronous machine based on cascaded sliding mode observer

Directory of Open Access Journals (Sweden)

Kai-Hui Zhao

2017-06-01

Full Text Available To improve the accuracy of torque control for vector control of interior permanent-magnet synchronous machine (IPMSM, this study proposes a torque-sensorless control method based on cascaded sliding mode observer (SMO. First, the active flux model is discussed, which converts the model of IPMSM into the equivalent model of surface-mounted permanent-magnet synchronous machine. Second, to reduce chattering caused by system parameters variations and external disturbances, the cascaded observer is designed, which is composed of a variable gain adaptive SMO and an active flux SMO. The variable gain adaptive SMO is designed to estimate the speed, rotor position and stator resistance in the d–q reference frame. The active flux SMO is designed to estimate the active flux and torque in the α–β reference frame. Global asymptotic stability of the observers is guaranteed by the Lyapunov stability analysis. Finally, simulations and experiments are carried out to verify the effectiveness of the proposed control scheme.

Measuring electromagnetic fields (EMF) around wind turbines in Canada: is there a human health concern?

Science.gov (United States)

McCallum, Lindsay C; Whitfield Aslund, Melissa L; Knopper, Loren D; Ferguson, Glenn M; Ollson, Christopher A

2014-02-15

The past five years has seen considerable expansion of wind power generation in Ontario, Canada. Most recently worries about exposure to electromagnetic fields (EMF) from wind turbines, and associated electrical transmission, has been raised at public meetings and legal proceedings. These fears have not been based on any actual measurements of EMF exposure surrounding existing projects but appear to follow from worries from internet sources and misunderstanding of the science. The study was carried out at the Kingsbridge 1 Wind Farm located near Goderich, Ontario, Canada. Magnetic field measurements were collected in the proximity of 15 Vestas 1.8 MW wind turbines, two substations, various buried and overhead collector and transmission lines, and nearby homes. Data were collected during three operational scenarios to characterize potential EMF exposure: 'high wind' (generating power), 'low wind' (drawing power from the grid, but not generating power) and 'shut off' (neither drawing, nor generating power). Background levels of EMF (0.2 to 0.3 mG) were established by measuring magnetic fields around the wind turbines under the 'shut off' scenario. Magnetic field levels detected at the base of the turbines under both the 'high wind' and 'low wind' conditions were low (mean = 0.9 mG; n = 11) and rapidly diminished with distance, becoming indistinguishable from background within 2 m of the base. Magnetic fields measured 1 m above buried collector lines were also within background (≤ 0.3 mG). Beneath overhead 27.5 kV and 500 kV transmission lines, magnetic field levels of up to 16.5 and 46 mG, respectively, were recorded. These levels also diminished rapidly with distance. None of these sources appeared to influence magnetic field levels at nearby homes located as close as just over 500 m from turbines, where measurements immediately outside of the homes were ≤ 0.4 mG. The results suggest that there is nothing unique to wind farms with respect to EMF exposure; in

Electron thermal EMF for NaxCu2-xS

Directory of Open Access Journals (Sweden)

Kuterbekov Kairat

2017-01-01

Full Text Available In the present study, the temperature dependences of the thermoelectromotive force (thermo–emf in copper selenide, substituted in a small concentration, were studied. The results of the measurements showed that the thermo–emf coefficient of the samples increases, and the conductivity decreases with increasing silver concentration in its composition. These results allow – with optimal selection of the doping regime and protective coatings – to develop on the basis of nanostructured copper selenide an effective thermoelectric for use at temperatures of 20–500°C as p–type semiconductors suitable for increasing the efficiency of thermoelectric generators.

Summary on Sensorless permanent magnet Brushless DC Motor Control Strategies

Directory of Open Access Journals (Sweden)

Li Hai Xia

2016-01-01

Full Text Available This paper aims at discussing the development process and application of permanent magnet brushless DC motor. By referring to the related literatures, this thesis gives an overview of several common non-position sensor detection technologies, analyzing their strengths and weaknesses as well as a number of new and improved methods in practical applications. Besides, The application situation of the electric door with sensorless permanent magnet brushless DC motor was illustrated.

A New Power-Factor-Based Vector Control Method for Sensorless Drive of Permanent-Magnet Synchronous Motors

Science.gov (United States)

Shinnaka, Shinji

As a simple vector control method for sensorless drives of permanent-magnet synchronous motors, the so-called “Power-Factor-Based (PFB) Vector Control Method” has been proposed. The conventional PFB method directly estimates the phase of the quasi-optimal stator current through a control of the power factor phase, instead of the estimation of the rotor phase. The stator current is controlled in the current reference frame whose secondary axis phase is the same as the stator current phase. This paper proposes a new PEB method where the stator current is controlled in the voltage reference frame whose secondary axis phase is the same as the voltage phase rather than the current phase. It is shown that the similar quasi-optimal stator current control can be attained through the current control with appropriate current commands taking the power factor phase into account. This paper also shows a practical method for generating the current commands and a practical guideline for the design parameters of the new PFB method.

Control algorithms and applications of the wavefront sensorless adaptive optics

Science.gov (United States)

Ma, Liang; Wang, Bin; Zhou, Yuanshen; Yang, Huizhen

2017-10-01

Compared with the conventional adaptive optics (AO) system, the wavefront sensorless (WFSless) AO system need not to measure the wavefront and reconstruct it. It is simpler than the conventional AO in system architecture and can be applied to the complex conditions. Based on the analysis of principle and system model of the WFSless AO system, wavefront correction methods of the WFSless AO system were divided into two categories: model-free-based and model-based control algorithms. The WFSless AO system based on model-free-based control algorithms commonly considers the performance metric as a function of the control parameters and then uses certain control algorithm to improve the performance metric. The model-based control algorithms include modal control algorithms, nonlinear control algorithms and control algorithms based on geometrical optics. Based on the brief description of above typical control algorithms, hybrid methods combining the model-free-based control algorithm with the model-based control algorithm were generalized. Additionally, characteristics of various control algorithms were compared and analyzed. We also discussed the extensive applications of WFSless AO system in free space optical communication (FSO), retinal imaging in the human eye, confocal microscope, coherent beam combination (CBC) techniques and extended objects.

Sensorless Vector Control of AC Induction Motor Using Sliding-Mode Observer

Directory of Open Access Journals (Sweden)

Phuc Thinh Doan

2013-06-01

Full Text Available This paper develops a sensorless vector controlled method for AC induction motor using sliding-mode observer. For developing the control algorithm, modeling of AC induction motor is presented. After that, a sliding mode observer is proposed to estimate the motor speed, the rotor flux, the angular position of the rotor flux and the motor torque from monitored stator voltages and currents. The use of the nonlinear sliding mode observer provides very good performance for both low and high speed motor operation. Furthermore, the proposed system is robust in motor losses and load variations. The convergence of the proposed observer is obtained using the Lyapunov theory. Hardware and software for simulation and experiment of the AC induction motor drive are introduced. The hardware consists of a 1.5kw AC induction motor connected in series with a torque sensor and a powder brake. A controller is developed based on DSP TMS320F28355. The simulation and experimental results illustrate that fast torque and speed response with small torque ripples can be achieved. The proposed control scheme is suitable to the application fields that require high performance of torque response such as electric vehicles. doi:http://dx.doi.org/10.12777/ijse.4.2.2013.39-43 [How to cite this article: Doan, P. T., Nguyen, T. T., Jeong, S. K., Oh, S. J., & Kim, S. B. (2013. Sensorless Vector Control of AC Induction Motor Using Sliding-Mode Observer. INTERNATIONAL JOURNAL OF SCIENCE AND ENGINEERING, 4(2, 39-43; doi: http://dx.doi.org/10.12777/ijse.4.2.2013.39-43

Speed Sensorless Field Oriented Control of an Induction Motor at zero speed with identification of inverter parameters

DEFF Research Database (Denmark)

Rasmussen, Henrik; Vadstrup, P.; Børsting, H.

2002-01-01

Using adaptive Lyapunov design a new approach for the design of an observer for speed sensorless control is developed. The resulting scheme leads to a nonlinear full order observer for the motor states and for the motor and inverter parameters including the rotor speed. Assuming motor parameters ...... known the design achieves stability with guaranteed region of attraction. Experiments demonstrate high dynamic performance even at zero rotor speed based only on the slip frequency caused by the load torque....

Rate of rotation measurement using back-EMFS associated with windings of a brushless DC motor

Science.gov (United States)

Howard, David E. (Inventor)

2000-01-01

A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is integrated and multiplied by the back-emf associated with an adjacent winding. The multiplied outputs associated with each winding are combined to produce a directionally sensitive DC output proportional only to the rate of rotation of the motor's shaft.

[The electromagnetic fields of the base stations of mobile radio communication and ecology. The estimation of danger of the base station EMF for population and for bioecosystems].

Science.gov (United States)

Grigor'ev, Iu G; Grigor'ev, K A

2005-01-01

The estimation of the danger for the population and for the bioecosistems of the electromagnetic conditions around of the base stations was given. The insufficiency of the scientific knowledge does not allow to guarantee the safety of the population and of the bioecosystems in the conditions of a round-the-clock long-term influence of EMF RF. WHO recommends to use "Precautionary principle".

Optimization of a therapeutic electromagnetic field (EMF) to retard breast cancer tumor growth and vascularity

OpenAIRE

Cameron, Ivan L; Markov, Marko S; Hardman, W Elaine

2014-01-01

Background This study provided additional data on the effects of a therapeutic electromagnetic field (EMF) device on growth and vascularization of murine 16/C mammary adenocarcinoma cells implanted in C3H/HeJ mice. Methods The therapeutic EMF device generated a defined 120 Hz semi sine wave pulse signal of variable intensity. Murine 16/C mammary adenocarcinoma tumor fragments were implanted subcutaneously between the scapulae of syngeneic C3H mice. Once the tumor grew to 100 mm3, daily EMF tr...

A novel unified DTC-SVM for sensorless induction motor drives fed by a matrix converter

DEFF Research Database (Denmark)

Lee, Kyo-Beum; Blaabjerg, Frede

2005-01-01

In this paper, a simple direct torque control (DTC) method for sensorless matrix converter drives is proposed, which is characterized by a simple structure, minimal torque ripple and unity input power factor. It is possible to combine the advantages of matrix converters with the advantages of the...

A Simple Sensorless Scheme for Induction Motor Drives Fed by a Matrix Converter Using Constant Air-Gap Flux and PQR Transformation

DEFF Research Database (Denmark)

Blaabjerg, Frede; Lee, Kyo Beum

2007-01-01

This paper presents a new and simple method for sensorless operation of matrix converter drives using a constant air-gap flux and the imaginary power flowing to the motor. To improve low-speed sensorless performance, the non-linearities of a matrix converter drive such as commutation delays, turn......-on and turn-off times of switching devices, and on-state switching device voltage drop are modeled using PQR transformation and compensated using a reference current control scheme. The proposed compensation method is applied for high performance induction motor drives using a 3 kW matrix converter system...

Fuzzy crane control with sensorless payload deflection feedback for vibration reduction

Science.gov (United States)

Smoczek, Jaroslaw

2014-05-01

Different types of cranes are widely used for shifting cargoes in building sites, shipping yards, container terminals and many manufacturing segments where the problem of fast and precise transferring a payload suspended on the ropes with oscillations reduction is frequently important to enhance the productivity, efficiency and safety. The paper presents the fuzzy logic-based robust feedback anti-sway control system which can be applicable either with or without a sensor of sway angle of a payload. The discrete-time control approach is based on the fuzzy interpolation of the controllers and crane dynamic model's parameters with respect to the varying rope length and mass of a payload. The iterative procedure combining a pole placement method and interval analysis of closed-loop characteristic polynomial coefficients is proposed to design the robust control scheme. The sensorless anti-sway control application developed with using PAC system with RX3i controller was verified on the laboratory scaled overhead crane.

Dynamic response evaluation of sensorless MPPT method for hybrid PV-DFIG wind turbine system

Directory of Open Access Journals (Sweden)

Danvu Nguyen

2016-01-01

Full Text Available This research proposes a sensorless Maximum Power Point Tracking (MPPT method for a hybrid Photovoltaic-Wind system, which consists of Photovoltaic (PV system and Doubly-Fed Induction Generator (DFIG Wind Turbine. In the hybrid system, the DC/DC converter output of the PV system is directly connected to the DC-link of DFIG’s back-to-back converter. Therefore, the PV inverter and its associated circuit can be removed in this structure. Typically, the PV power is monitored by using PV current sensor and PV voltage sensor for MPPT. In this paper, the powers of converters on grid side and rotor side of DFIG are used to estimate the PV power without the PV current sensor. That can efficiently reduce the cost of the hybrid system. The detailed analysis of the sensorless MPPT method, which includes derived equations and operation response, is also presented in this paper. In addition, an overview of PV-DFIG research in literature is stated to supply comprehensive knowledge of related research.

Investigation of wire motion in superconducting magnets

International Nuclear Information System (INIS)

Ogitsu, T.; Tsuchiya, K.; Devred, A.

1990-09-01

The large Lorentz forces occuring during the excitation of superconducting magnets can provoke sudden motions of wire, which eventually release enough energy to trigger a quench. These wire motions are accompanied by two electromagnetic effects: an induced emf along the moved wire, and a local change in flux caused by the minute dislocation of current. Both effects cause spikes in the coil voltage. Voltage data recorded during the excitation of a superconducting quadrupole magnet which early exhibit such events are here reported. Interpretations of the voltage spikes in terms of energy release are also presented, leading to insights on the spectrum of the disturbances which occur in real magnets. 15 refs

Sensorless DTC-SVM for Induction Motor Driven by a Matrix Converter Using a Parameter Estimation Strategy

DEFF Research Database (Denmark)

Blaabjerg, Frede; Lee, Kyo-Beum

2008-01-01

This paper presents a new direct torque controlled space vector modulated method to improve the sensorless performance of matrix converter drives using a parameter estimation scheme. The flux and torque error are geometrically combined in a new flux leakage vector to make a stator command voltage...

Comparison of a triaxial fluxgate magnetometer and Toftness sensometer for body surface EMF measurement.

Science.gov (United States)

Zhang, John; Toftness, Dave; Snyder, Brian; Nosco, Dennis; Balcavage, Walter; Nindl, Gabi

2004-12-01

The use of magnetic fields to treat disease has intrigued mankind since the time of the ancient Greeks. More recently it has been shown that electromagnetic field (EMF) treatment aids bone healing, and repetitive transcranial magnetic stimulation (rTMS) appears to be beneficial in treating schizophrenia and depression. Since external EMFs influence internal body processes, we hypothesized that measurement of body surface EMFs might be used to detect disease states and direct the course of subsequent therapy. However, measurement of minute body surface EMFs requires use of a sensitive and well documented magnetometer. In this study we evaluated the sensitivity and frequency response of a fluxgate magnetometer with a triaxial probe for use in detecting body surface EMF and we compared the magnetometer readings with a signal from a Toftness Sensometer, operated by an experienced clinician, in the laboratory and in a clinical setting. A Peavy Audio Amplifier and variable power output Telulex signal generator were used to develop 50 microT EMFs in a three coil Merritt coil system. A calibrated magnetometer was used to set a 60 Hz 50 microT field in the coil and an ammeter was used to measure the current required to develop the 50 microT field. At frequencies other than 60 Hz, the field strength was maintained at 50 microT by adjusting the Telulex signal output to keep the current constant. The field generated was monitored using a 10 turn coil connected to an oscilloscope. The oscilloscope reading indicated that the field strength was the same at all frequencies tested. To determine if there was a correspondence between the signals detected by a fluxgate magnetometer (FGM1) and the Toftness Sensometer both devices were placed in the Merritt coil and readings were recorded from the FGM1 and compared with the ability of a highly experienced Toftness operator to detect the 50 microT field. Subsequently, in a clinical setting, FGM1 readings made by an FGM1 technician and

Extremely low frequency electromagnetic field (ELF-EMF) reduces oxidative stress and improves functional and psychological status in ischemic stroke patients.

Science.gov (United States)

Cichoń, Natalia; Bijak, Michał; Miller, Elżbieta; Saluk, Joanna

2017-07-01

As a result of ischaemia/reperfusion, massive generation of reactive oxygen species occurs, followed by decreased activity of antioxidant enzymes. Extremely low frequency electromagnetic fields (ELF-EMF) can modulate oxidative stress, but there are no clinical antioxidant studies in brain stroke patients. The aim of our study was to investigate the effect of ELF-EMF on clinical and antioxidant status in post-stroke patients. Fifty-seven patients were divided into two groups: ELF-EMF and non-ELF-EMF. Both groups underwent the same 4-week rehabilitation program. Additionally, the ELF-EMF group was exposed to an ELF-EMF field of 40 Hz, 7 mT for 15 min/day for 4 weeks (5 days a week). The activity of catalase and superoxide dismutase was measured in hemolysates, and total antioxidant status (TAS) determined in plasma. Functional status was assessed before and after the series of treatments using Activities of Daily Living (ADL), Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS). Applied ELF-EMF significantly increased enzymatic antioxidant activity; however, TAS levels did not change in either group. Results show that ELF-EMF induced a significant improvement in functional (ADL) and mental (MMSE, GDS) status. Clinical parameters had positive correlation with the level of enzymatic antioxidant protection. Bioelectromagnetics. 38:386-396, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Sensorless speed detection of squirrel-cage induction machines using stator neutral point voltage harmonics

Science.gov (United States)

Petrovic, Goran; Kilic, Tomislav; Terzic, Bozo

2009-04-01

In this paper a sensorless speed detection method of induction squirrel-cage machines is presented. This method is based on frequency determination of the stator neutral point voltage primary slot harmonic, which is dependent on rotor speed. In order to prove method in steady state and dynamic conditions the simulation and experimental study was carried out. For theoretical investigation the mathematical model of squirrel cage induction machines, which takes into consideration actual geometry and windings layout, is used. Speed-related harmonics that arise from rotor slotting are analyzed using digital signal processing and DFT algorithm with Hanning window. The performance of the method is demonstrated over a wide range of load conditions.

Study of extremely low frequency electromagnetic field (ELF EMF) radiation produced by consumer products

International Nuclear Information System (INIS)

Roha Tukimin; Ahmad Fazli Ahmad Sanusi; Rozaimah Abd Rahim; Mohd Yusof Mohd Ali; Mohamad Amirul Nizam Mohamad Thari

2006-01-01

Extremely low frequency electromagnetic field ( ELF EMF) radiation falls under category of non-ionising radiation (NIR).ELF EMF consists of electric and magnetic fields. Excessive exposure to ELF EMF radiation may cause biological and health effects to human beings such as behavioral changes, stochastic and as initiator of cancer. In daily life, the main source of extremely low frequency electromagnetic radiation are consumer products in our home and office. Due to its ability to cause hazard, a study of ELF EMF radiation produced by consumer product was conducted. For this preliminary study, sample of 20 types electrical appliances were selected. The measurement was covered electric and magnetic field strength produced by the sample. PMM model EHP50A were used for measurement and data analysis. The results were compared with the permissible limits recommended by International Commission of Non-Ionising Radiation Protection (ICNIRP) for members of public (1000 mGauss and 5000 V/m). The results showed that all tested sample produced magnetic and electric field but still under the permissible limit recommended by ICNIRP. Besides that we found that field strengths can be very high at closer distance to the sample. (Author)

The precautionary principle and EMF: from the theory to the practice

International Nuclear Information System (INIS)

Lambrozo, J.

2002-01-01

In 1992 the United Nations Declaration on the Environment stated that where there are threats of serious or irreversible damage, lack of full scientific certainty will not be used as a reason for postponing cost-effective measures to prevent environmental degradation. Since this interpretation has been reaffirmed within numerous framework conventions and national environment law in a number of countries has begun to incorporate it. The contents of the precautionary principle: There are in fact two completely different ideas about the principle: the absolute: the precautionary principle would aim to guarantee complete harmless. The aim is zero risk and even a minimal suspicion of risk should result in a moratorium or a definitive ban, the moderate: its implementation is subject to a scientifically credible statement of hypothetical risk. It also gives priority to positive measures particularly research to provide a better assessment of the risk. In every case, before any decision a statement of cost and of advantages should be drawn up. The concept of prudent avoidance introduced in 1989 by G. Morgan and adopted by some states (Sweden, Australia) seems to be a specific application of the precautionary principle to EMF, taking into account the cost of the policy. The EMF research: After more than 20 years of research (epidemiological residential and professional studies, in vitro studies and laboratory animal studies) the scientific uncertainty has been considerably reduced but the possibility of some adverse effects remains. This fact and the public concern about EMF (partly explained by the ubiquity of exposure) explain the temptations in applying the precautionary principle to the EMF issue

A Novel Sensorless Control Strategy for Brushless Direct Current Motor Based on the Estimation of Line Back Electro-Motive Force

Directory of Open Access Journals (Sweden)

Chengde Tong

2017-09-01

Full Text Available In this paper, a novel sensorless control strategy based on the estimation of line back electro-motive force (BEMF is proposed. According to the phase relationship between the ideal commutation points of the brushless direct current motor (BLDCM and the zero-crossing points (ZCPs of the line BEMF, the calculation formula of line BEMF is simplified properly and the commutation rule for different positions of the rotor is presented. The estimation error of line BEMF caused by the freewheeling current of silent phase is analyzed, and the solution is given. With the phase shift of the low-pass filter considered, a compensation method using “60°-α” and “120°-α” is studied in this paper to eliminate the error. Finally, the simulation and experimental results show that the rotor-position-detection error is reduced effectively and the motor driven by the accurate commutation signal can work well at low and high speed.

RF-EMF exposure of fetus and mother during magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Pediaditis, M; Leitgeb, N; Cech, R [Institute of Health Care Engineering with European Notified Body of Medical Devices, Graz University of Technology, Inffeldgasse 18, 8010 Graz (Austria)], E-mail: norbert.leitgeb@tugraz.at

2008-12-21

Magnetic resonance imaging (MRI) avoids risks of genetic damage but may be associated with excess heating of body tissues. To investigate the exposure to MRI radio-frequency (RF) electromagnetic fields (EMF), low-pass and high-pass birdcage coils were simulated and the whole-body pregnant woman model SILVY used to determine local and whole-body specific absorption rates (SAR) in mother and fetus. Resonant RF-EMF of MRI devices were investigated at 0.3, 1, 1.5, 2, 3 and 4 T. Results allow extrapolation also to higher fields. They showed that local SAR in mother's trunk reaches exposure limits first. However, data show that during abdominal MRI meeting exposure limits of the mother is not sufficient to protect the fetus if limits of the general populations are applied to it. In that case fetal whole-body SAR exceeds limits by 7.4-fold. It is up to the physician and/or the ethics commission to decide upon justification for abdominal MRI of pregnant women if limits are exceeded. The results indicate the need for specifically addressing fetal exposure to EMF and elaborating general recommendations by radiation protection bodies.

RF-EMF exposure of fetus and mother during magnetic resonance imaging

International Nuclear Information System (INIS)

Pediaditis, M; Leitgeb, N; Cech, R

2008-01-01

Magnetic resonance imaging (MRI) avoids risks of genetic damage but may be associated with excess heating of body tissues. To investigate the exposure to MRI radio-frequency (RF) electromagnetic fields (EMF), low-pass and high-pass birdcage coils were simulated and the whole-body pregnant woman model SILVY used to determine local and whole-body specific absorption rates (SAR) in mother and fetus. Resonant RF-EMF of MRI devices were investigated at 0.3, 1, 1.5, 2, 3 and 4 T. Results allow extrapolation also to higher fields. They showed that local SAR in mother's trunk reaches exposure limits first. However, data show that during abdominal MRI meeting exposure limits of the mother is not sufficient to protect the fetus if limits of the general populations are applied to it. In that case fetal whole-body SAR exceeds limits by 7.4-fold. It is up to the physician and/or the ethics commission to decide upon justification for abdominal MRI of pregnant women if limits are exceeded. The results indicate the need for specifically addressing fetal exposure to EMF and elaborating general recommendations by radiation protection bodies.

Residential exposure from extremely low frequency electromagnetic field (ELF EMF) radiation

Science.gov (United States)

Parthasarathy, Shamesh Raj; Tukimin, Roha

2018-01-01

ELF EMF radiation have received considerable attention as a potential threat to the safety and health of people living in the vicinity of high voltage transmission lines, electric distribution substations, power stations and even in close proximity to electronics and electrical household appliances. The paper highlights the study on the ELF EMF safety assessment performed at residences comprising of an owner-occupied house, a completed vacant house and an under construction condominium. The objectives of this study were to determine the ELF EMF radiation exposure level from the high voltage transmission line, electric distribution substation, power station and electrical household appliances in the residences, and to assess the potential exposure received by the occupants at the assessed locations. The results were logged in the electric and magnetic field strength with the units of volt per meter (V/m) and miliGauss (mG) respectively. The instrument setup and measurement protocols during the assessment were adopted from standard measurement method and procedures stipulated under the Institute of Electrical and Electronics Engineers (IEEE) Standard. The results were compared with the standards recommended in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines.

Comprehensive personal RF-EMF exposure map and its potential use in epidemiological studies.

Science.gov (United States)

Gonzalez-Rubio, Jesus; Najera, Alberto; Arribas, Enrique

2016-08-01

In recent years, numerous epidemiological studies, which deal with the potential effects of mobile phone antennas on health, have almost exclusively focused on their distance to mobile phone base stations. Although it is known that this is not the best approach to the problem, this situation occurs due to the numerous difficulties when determining the personal exposure to the radiofrequency electromagnetic fields (RF-EMF). However, due to the rise of personal exposimeters, the evolution of spatial statistics, the development of geographical information systems and the use of powerful software, new alternatives are available to deal with these epidemiological studies and thus overcome the aforementioned difficulties. Using these tools, this paper presents a lattice map of personal RF-EMF exposure from exterior mobile phone base stations, covering the entire 110 administrative regions in the city of Albacete (Spain). For this purpose, we used a personal exposimeter, Satimo EME Spy 140 model, performing measurements every 4s The exposimeter was located inside the plastic basket of a bicycle, whose versatility permitted the access to all the zones of the city. Once the exposure map was prepared, its relation with the known antenna locations was studied. The 64 mobile telephone antennas of the city were also georeferenced; the randomness of both variables (exposure and antennas) were studied by means of the Moran's I test. Results showed that the distribution of the antennas follows a grouped pattern (pbased on the mean exposure values to RF-EMF in these sections. The displayed map would permit the execution of more accurate epidemiological studies, since it would be possible to compare the exposure measurements with the incidence data of a disease. Copyright © 2016 Elsevier Inc. All rights reserved.

Magnetic sensorless control experiment without drift problem on HT-7

International Nuclear Information System (INIS)

Nakamura, K.; Luo, J.R.; Wang, H.Z.; Ji, Z.S.; Wang, H.; Wang, F.; Qi, N.; Sato, K.N.; Hanada, K.; Sakamoto, M.; Idei, H.; Hasegawa, M.; Iyomasa, A.; Kawasaki, S.; Nakashima, H.; Higashijima, A.

2006-01-01

Magnetic sensorless control experiments of the plasma horizontal position have been carried out in the superconducting tokamak HT-7. Previously the horizontal position was calculated from the vertical field coil current and voltage without using signals of magnetic sensors like magnetic coils and flux loops placed near the plasma. The calculations are made focusing on the ripple frequency component of the power supply with thyristor and directly from them without time integration. There is no drift problem of integrator of magnetic sensors. Two kinds of experiments were carried out, to keep the position constant and swing the position in a triangular waveform

Two-frequency method for measuring Hall emf in high-resistive materials with charge-carrier low mobility

International Nuclear Information System (INIS)

Aleksandrov, A.L.; Vedeneev, A.S.; Gulyaev, I.B.; Zhdan, A.G.

1982-01-01

A facility for measuring Hall emf in high-resistive materials with low mobility of charge carriers by the two-frequency method using digital synchronous integration is described. The facility permits to detect the minimum Hall emf approxamatety equat to 5 μV at approximatety equal to 1 T Ohm of the investigated.sample resistance during the measuring time of approximately equal to 2000 s. Sensitivity by Hall mobility makes up >= 0.01 cm 2 /Vxs at the same measuring time. Measuring results of the Hall emf on GaAs monocrystals, CdSe films and island film of gold are presented

Dynamic Control of Adsorption Sensitivity for Photo-EMF-Based Ammonia Gas Sensors Using a Wireless Network

Directory of Open Access Journals (Sweden)

Yuriy Vashpanov

2011-11-01

Full Text Available This paper proposes an adsorption sensitivity control method that uses a wireless network and illumination light intensity in a photo-electromagnetic field (EMF-based gas sensor for measurements in real time of a wide range of ammonia concentrations. The minimum measurement error for a range of ammonia concentration from 3 to 800 ppm occurs when the gas concentration magnitude corresponds with the optimal intensity of the illumination light. A simulation with LabView-engineered modules for automatic control of a new intelligent computer system was conducted to improve measurement precision over a wide range of gas concentrations. This gas sensor computer system with wireless network technology could be useful in the chemical industry for automatic detection and measurement of hazardous ammonia gas levels in real time.

Electric shock and elevated EMF levels due to triplen harmonics

International Nuclear Information System (INIS)

Tran, T.Q.; Conrad, L.E.; Stallman, B.K.

1996-01-01

The increasing use of single phase rectifiers for electric power conversion in residential applications increases harmonic load on utility systems. Many papers have analyzed the effect of these loads on power quality and equipment loadability. However, there are two more critical concerns for harmonic loads served phase to neutral on multi-grounded wye systems. Triplen harmonics, particularly the third, add in the neutral and have little diversity between loads. The higher neutral currents may cause significant problems. Neutral to earth voltages will increase near the substations which could increase stray voltage complaints. The additional neutral current on three phase lines will elevate EMF levels especially in the fringe areas. This paper provides fundamental understanding of triplen harmonic influence on stray voltage and EMF related to multi-grounded wye electric distribution systems

Down-Regulation of OsEMF2b Caused Semi-sterility Due to Anther and Pollen Development Defects in Rice

Directory of Open Access Journals (Sweden)

Luchang Deng

2017-11-01

Full Text Available Anther and pollen development are crucial processes of plant male reproduction. Although a number of genes involved in these processes have been identified, the regulatory networks of pollen and anther development are still unclear. EMBRYONIC FLOWER 2b (OsEMF2b is important for rice development. Its biological function in floral organ, flowering time and meristem determinacy have been well-studied, but its role, if only, on male reproduction is still unknown, because null mutants of OsEMF2b barely have anthers. In this study, we identified a weak allele of OsEMF2b, osemf2b-4. The T-DNA insertion was located in the promoter region of OsEMF2b, and OsEMF2b expression was significantly decreased in osemf2b-4. The osemf2b-4 mutant exhibited much more normal anthers than null mutants of OsEMF2b, and also showed defective floret development similar to null mutants. Cytological analysis showed various defects of anther wall and pollen development in osemf2b-4, such as slightly or extremely enlarged tapetum, irregular or normal morphology microspores, and partial or complete sterility. OsEMF2b was highly expressed in tapetum and microspores, and the protein was localized in the nucleus. The expression of 15 genes essential for anther and pollen development was investigated in both WT and osemf2b-4. Fourteen genes including GAMYB was up-regulated, and only PTC1 was down-regulated in osemf2b-4. This suggests that up-regulated GAMYB and down-regulated PTC1 might contribute to the defective anther and pollen development in osemf2b-4. Overall, our work suggests that OsEMF2b plays an essential role during post-meiotic anther and pollen development.

Development of an RF-EMF Exposure Surrogate for Epidemiologic Research.

Science.gov (United States)

Roser, Katharina; Schoeni, Anna; Bürgi, Alfred; Röösli, Martin

2015-05-22

Exposure assessment is a crucial part in studying potential effects of RF-EMF. Using data from the HERMES study on adolescents, we developed an integrative exposure surrogate combining near-field and far-field RF-EMF exposure in a single brain and whole-body exposure measure. Contributions from far-field sources were modelled by propagation modelling and multivariable regression modelling using personal measurements. Contributions from near-field sources were assessed from both, questionnaires and mobile phone operator records. Mean cumulative brain and whole-body doses were 1559.7 mJ/kg and 339.9 mJ/kg per day, respectively. 98.4% of the brain dose originated from near-field sources, mainly from GSM mobile phone calls (93.1%) and from DECT phone calls (4.8%). Main contributors to the whole-body dose were GSM mobile phone calls (69.0%), use of computer, laptop and tablet connected to WLAN (12.2%) and data traffic on the mobile phone via WLAN (6.5%). The exposure from mobile phone base stations contributed 1.8% to the whole-body dose, while uplink exposure from other people's mobile phones contributed 3.6%. In conclusion, the proposed approach is considered useful to combine near-field and far-field exposure to an integrative exposure surrogate for exposure assessment in epidemiologic studies. However, substantial uncertainties remain about exposure contributions from various near-field and far-field sources.

Wind Velocity and Position Sensor-less Operation for PMSG Wind Generator

Science.gov (United States)

Senjyu, Tomonobu; Tamaki, Satoshi; Urasaki, Naomitsu; Uezato, Katsumi; Funabashi, Toshihisa; Fujita, Hideki

Electric power generation using non-conventional sources is receiving considerable attention throughout the world. Wind energy is one of the available non-conventional energy sources. Electrical power generation using wind energy is possible in two ways, viz. constant speed operation and variable speed operation using power electronic converters. Variable speed power generation is attractive, because maximum electric power can be generated at all wind velocities. However, this system requires a rotor speed sensor, for vector control purpose, which increases the cost of the system. To alleviate the need of rotor speed sensor in vector control, we propose a new sensor-less control of PMSG (Permanent Magnet Synchronous Generator) based on the flux linkage. We can estimate the rotor position using the estimated flux linkage. We use a first-order lag compensator to obtain the flux linkage. Furthermore‚we estimate wind velocity and rotation speed using a observer. The effectiveness of the proposed method is demonstrated thorough simulation results.

Sensorless direct voltage control of the stand-alone brushless doubly-fed generator

DEFF Research Database (Denmark)

Liu, Yi; Xu, Wei; Xiong, Fei

2017-01-01

The conventional stand-alone brushless doubly-fed generator (BDFG) control strategies need the feedback from the rotor position or speed sensors, which can reduce system reliability and increase the cost and axial volume of the machine. In this paper, a sensorless direct voltage control (DVC) str......) strategy is presented for the stand-alone BDFG. The satisfactory dynamic performance is verified by experimental results under four kinds of typical operation conditions. Besides, the proposed control strategy is robust due to no generator parameters being required....

International policy and advisory response regarding children's exposure to radio frequency electromagnetic fields (RF-EMF).

Science.gov (United States)

Redmayne, Mary

2016-01-01

Radiofrequency electromagnetic field (RF-EMF) exposure regulations/guidelines generally only consider acute effects, and not chronic, low exposures. Concerns for children's exposure are warranted due to the amazingly rapid uptake of many wireless devices by increasingly younger children. This review of policy and advice regarding children's RF-EMF exposure draws material from a wide variety of sources focusing on the current situation. This is not a systematic review, but aims to provide a representative cross-section of policy and advisory responses within set boundaries. There are a wide variety of approaches which I have categorized and tabulated ranging from ICNIRP/IEEE guidelines and "no extra precautions needed" to precautionary or scientific much lower maxima and extensive advice to minimize RF-EMF exposure, ban advertising/sale to children, and add exposure information to packaging. Precautionary standards use what I term an exclusion principle. The wide range of policy approaches can be confusing for parents/carers of children. Some consensus among advisory organizations would be helpful acknowledging that, despite extensive research, the highly complex nature of both RF-EMF and the human body, and frequent technological updates, means simple assurance of long-term safety cannot be guaranteed. Therefore, minimum exposure of children to RF-EMF is recommended. This does not indicate need for alarm, but mirrors routine health-and-safety precautions. Simple steps are suggested. ICNIRP guidelines need to urgently publish how the head, torso, and limbs' exposure limits were calculated and what safety margin was applied since this exposure, especially to the abdomen, is now dominant in many children.

Maximum power point tracking-based control algorithm for PMSG wind generation system without mechanical sensors

International Nuclear Information System (INIS)

Hong, Chih-Ming; Chen, Chiung-Hsing; Tu, Chia-Sheng

2013-01-01

Highlights: ► This paper presents MPPT based control for optimal wind energy capture using RBFN. ► MPSO is adopted to adjust the learning rates to improve the learning capability. ► This technique can maintain the system stability and reach the desired performance. ► The EMF in the rotating reference frame is utilized in order to estimate speed. - Abstract: This paper presents maximum-power-point-tracking (MPPT) based control algorithms for optimal wind energy capture using radial basis function network (RBFN) and a proposed torque observer MPPT algorithm. The design of a high-performance on-line training RBFN using back-propagation learning algorithm with modified particle swarm optimization (MPSO) regulating controller for the sensorless control of a permanent magnet synchronous generator (PMSG). The MPSO is adopted in this study to adapt the learning rates in the back-propagation process of the RBFN to improve the learning capability. The PMSG is controlled by the loss-minimization control with MPPT below the base speed, which corresponds to low and high wind speed, and the maximum energy can be captured from the wind. Then the observed disturbance torque is feed-forward to increase the robustness of the PMSG system

Practical Wide-speed-range Sensorless Control System for Permanent Magnet Reluctance Synchronous Motor Drives via Active Flux Model

DEFF Research Database (Denmark)

Ancuti, Mihaela Codruta; Tutelea, Lucian; Andreescu, Gheorghe-Daniel

2014-01-01

This article introduces a control strategy to obtain near-maximum available torque in a wide speed range with sensorless operation via the active flux concept for permanent magnet-reluctance synchronous motor drives. A new torque dq current reference calculator is proposed, with reference torque...

Effects of extremely low frequency electromagnetic field (ELF-EMF) on catalase, cytochrome P450 and nitric oxide synthase in erythro-leukemic cells.

Science.gov (United States)

Patruno, Antonia; Tabrez, Shams; Pesce, Mirko; Shakil, Shazi; Kamal, Mohammad A; Reale, Marcella

2015-01-15

Extremely low frequency electromagnetic fields (ELF-EMFs) are widely employed in electrical appliances and different equipment such as television sets, mobile phones, computers and microwaves. The molecular mechanism through which ELF-EMFs can influence cellular behavior is still unclear. A hypothesis is that ELF-EMFs could interfere with chemical reactions involving free radical production. Under physiologic conditions, cells maintain redox balance through production of ROS/RNS and antioxidant molecules. The altered balance between ROS generation and elimination plays a critical role in a variety of pathologic conditions including neurodegenerative diseases, aging and cancer. Actually, there is a disagreement as to whether there is a causal or coincidental relationship between ELF-EMF exposure and leukemia development. Increased ROS levels have been observed in several hematopoietic malignancies including acute and chronic myeloid leukemias. In our study, the effect of ELF-EMF exposure on catalase, cytochrome P450 and inducible nitric oxide synthase activity and their expression by Western blot analysis in myelogenous leukemia cell line K562 was evaluated. A significant modulation of iNOS, CAT and Cyt P450 protein expression was recorded as a result of ELF-EMF exposure in both phorbol 12-myristate 13-acetate (PMA)-stimulated and non-stimulated cell lines. Modulation in kinetic parameters of CAT, CYP-450 and iNOS enzymes in response to ELF-EMF indicates an interaction between the ELF-EMF and the enzymological system. These new insights might be important in establishing a mechanistic framework at the molecular level within which the possible effects of ELF-EMF on health can be understood. Copyright © 2014 Elsevier Inc. All rights reserved.

[Polish guidelines of 2001 for maximum admissible intensities in high frequency EMF versus European Union recommendations].

Science.gov (United States)

Aniołczyk, Halina

2003-01-01

In 1999, a draft of amendments to maximum admissible intensities (MAI) of electromagnetic fields (0 Hz-300 GHz) was prepared by Professor H. Korniewicz of the Central Institute for Labour Protection, Warsaw, in cooperation with the Nofer Institute of Occupational Medicine, Łódź (radio- and microwaves) and the Military Institute of Hygiene and Epidemiology, Warsaw (pulse radiation). Before 2000, the development of the national MAI guidelines for the frequency range of 0.1 MHz-300 GHz was based on the knowledge of biological and health effects of EMF exposure available on the turn of the 1960s. A current basis for establishing the MAI international standards is a well-documented thermal effect measured by the value of a specific absorption rate (SAR), whereas the effects of resonant absorption imposes the nature of the functional dependency on EMF frequency. The Russian standards, already thoroughly analyzed, still take so-called non-thermal effects and the conception of energetic load for a work-shift with its progressive averaging (see hazardous zone in Polish guidelines) as a basis for setting maximum admissible intensities. The World Health Organization recommends a harmonization of the EMF protection guidelines, existing in different countries, with the guidelines of the International Commission for Non-Ionizing Radiation Protection (ICNIRP), and its position is supported by the European Union.

Five years later: the current status of the use of proteomics and transcriptomics in EMF research.

Science.gov (United States)

Leszczynski, Dariusz; de Pomerai, David; Koczan, Dirk; Stoll, Dieter; Franke, Helmut; Albar, Juan Pablo

2012-08-01

The World Health Organization's and Radiation and Nuclear Safety Authority's "Workshop on Application of Proteomics and Transcriptomics in Electromagnetic Fields Research" was held in Helsinki in the October/November 2005. As a consequence of this meeting, Proteomics journal published in 2006 a special issue "Application of Proteomics and Transcriptomics in EMF Research" (Vol. 6 No. 17; Guest Editor: D. Leszczynski). This Proteomics issue presented the status of research, of the effects of electromagnetic fields (EMF) using proteomics and transcriptomics methods, present in 2005. The current overview/opinion article presents the status of research in this area by reviewing all studies that were published by the end of 2010. The review work was a part of the European Cooperation in the Field of Scientific and Technical Research (COST) Action BM0704 that created a structure in which researchers in the field of EMF and health shared knowledge and information. The review was prepared by the members of the COST Action BM0704 task group on the high-throughput screening techniques and electromagnetic fields (TG-HTST-EMF). © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of an RF-EMF Exposure Surrogate for Epidemiologic Research

Directory of Open Access Journals (Sweden)

Katharina Roser

2015-05-01

Full Text Available Exposure assessment is a crucial part in studying potential effects of RF-EMF. Using data from the HERMES study on adolescents, we developed an integrative exposure surrogate combining near-field and far-field RF-EMF exposure in a single brain and whole-body exposure measure. Contributions from far-field sources were modelled by propagation modelling and multivariable regression modelling using personal measurements. Contributions from near-field sources were assessed from both, questionnaires and mobile phone operator records. Mean cumulative brain and whole-body doses were 1559.7 mJ/kg and 339.9 mJ/kg per day, respectively. 98.4% of the brain dose originated from near-field sources, mainly from GSM mobile phone calls (93.1% and from DECT phone calls (4.8%. Main contributors to the whole-body dose were GSM mobile phone calls (69.0%, use of computer, laptop and tablet connected to WLAN (12.2% and data traffic on the mobile phone via WLAN (6.5%. The exposure from mobile phone base stations contributed 1.8% to the whole-body dose, while uplink exposure from other people’s mobile phones contributed 3.6%. In conclusion, the proposed approach is considered useful to combine near-field and far-field exposure to an integrative exposure surrogate for exposure assessment in epidemiologic studies. However, substantial uncertainties remain about exposure contributions from various near-field and far-field sources.

An Adaptive Supervisory Sliding Fuzzy Cerebellar Model Articulation Controller for Sensorless Vector-Controlled Induction Motor Drive Systems

Directory of Open Access Journals (Sweden)

Shun-Yuan Wang

2015-03-01

Full Text Available This paper presents the implementation of an adaptive supervisory sliding fuzzy cerebellar model articulation controller (FCMAC in the speed sensorless vector control of an induction motor (IM drive system. The proposed adaptive supervisory sliding FCMAC comprised a supervisory controller, integral sliding surface, and an adaptive FCMAC. The integral sliding surface was employed to eliminate steady-state errors and enhance the responsiveness of the system. The adaptive FCMAC incorporated an FCMAC with a compensating controller to perform a desired control action. The proposed controller was derived using the Lyapunov approach, which guarantees learning-error convergence. The implementation of three intelligent control schemes—the adaptive supervisory sliding FCMAC, adaptive sliding FCMAC, and adaptive sliding CMAC—were experimentally investigated under various conditions in a realistic sensorless vector-controlled IM drive system. The root mean square error (RMSE was used as a performance index to evaluate the experimental results of each control scheme. The analysis results indicated that the proposed adaptive supervisory sliding FCMAC substantially improved the system performance compared with the other control schemes.

Sensorless Speed/Torque Control of DC Machine Using Artificial Neural Network Technique

Directory of Open Access Journals (Sweden)

Rakan Kh. Antar

2017-12-01

Full Text Available In this paper, Artificial Neural Network (ANN technique is implemented to improve speed and torque control of a separately excited DC machine drive. The speed and torque sensorless scheme based on ANN is estimated adaptively. The proposed controller is designed to estimate rotor speed and mechanical load torque as a Model Reference Adaptive System (MRAS method for DC machine. The DC drive system consists of four quadrant DC/DC chopper with MOSFET transistors, ANN, logic gates and routing circuits. The DC drive circuit is designed, evaluated and modeled by Matlab/Simulink in the forward and reverse operation modes as a motor and generator, respectively. The DC drive system is simulated at different speed values (±1200 rpm and mechanical torque (±7 N.m in steady state and dynamic conditions. The simulation results illustratethe effectiveness of the proposed controller without speed or torque sensors.

Sensorless adaptive optics for isoSTED nanoscopy

Science.gov (United States)

Antonello, Jacopo; Hao, Xiang; Allgeyer, Edward S.; Bewersdorf, Joerg; Rittscher, Jens; Booth, Martin J.

2018-02-01

The presence of aberrations is a major concern when using fluorescence microscopy to image deep inside tissue. Aberrations due to refractive index mismatch and heterogeneity of the specimen under investigation cause severe reduction in the amount of fluorescence emission that is collected by the microscope. Furthermore, aberrations adversely affect the resolution, leading to loss of fine detail in the acquired images. These phenomena are particularly troublesome for super-resolution microscopy techniques such as isotropic stimulated-emission-depletion microscopy (isoSTED), which relies on accurate control of the shape and co-alignment of multiple excitation and depletion foci to operate as expected and to achieve the super-resolution effect. Aberrations can be suppressed by implementing sensorless adaptive optics techniques, whereby aberration correction is achieved by maximising a certain image quality metric. In confocal microscopy for example, one can employ the total image brightness as an image quality metric. Aberration correction is subsequently achieved by iteratively changing the settings of a wavefront corrector device until the metric is maximised. This simplistic approach has limited applicability to isoSTED microscopy where, due to the complex interplay between the excitation and depletion foci, maximising the total image brightness can lead to introducing aberrations in the depletion foci. In this work we first consider the effects that different aberration modes have on isoSTED microscopes. We then propose an iterative, wavelet-based aberration correction algorithm and evaluate its benefits.

Performance Improvement of Sensorless Vector Control for Matrix Converter Drives Using PQR Transformation

DEFF Research Database (Denmark)

Lee, Kyo-Beum; Blaabjerg, Frede

2005-01-01

This paper presents a new method to improve sensorless performance of matrix converter drives using PQR power transformation. The non-linearity of matrix converter drives such as commutation delay, turn-on and turn-off time of switching device, and on-state switching device voltage drop is modelled...... using PQR transformation and compensated using a reference current control scheme. To eliminate the input current distortion due to the input voltage unbalance, a simple method using PQR transformation is also proposed. The proposed compensation method is applied for high performance induction motor...

Performance Improvement of Sensorless Vector Control for Induction Motor Drives Fed by Matrix Converter Using Nonlinear Model and Disturbance Observer

DEFF Research Database (Denmark)

Lee, Kyo-Beum; Blaabjerg, Frede

2004-01-01

This paper presents a new sensorless vector control system for high performance induction motor drives fed by a matrix converter with a non-linearity compensation and disturbance observer. The nonlinear voltage distortion that is caused by communication delay and on-state voltage drop in switching...

Newly developed EMF cell with zirconia solid electrolyte for measurement of low oxygen potentials in liquid Cu-Cr and Cu-Zr alloys

Directory of Open Access Journals (Sweden)

Katayama I.

2012-01-01

Full Text Available In order to measure the very low oxygen potential by use of stabilized zirconia solid electrolyte emf method, a new cell construction was devised. The idea was based on Janke but a zirconia rod was used instead of the zirconia crucible which contacts liquid alloy electrode. The cell was used for determination of the oxygen potentials in liquid dilute Cu-Cr and Cu-Zr alloys. The reference electrode was Cr,Cr2O3. Emf measurements were performed in the temperature range of 1400-1580K and composition range of 0.198-3.10at%Cr-Cu alloys, and 1380-1465K, 0.085-0.761at%Zr-Cu alloys. The composition of liquid alloys were determined by picking up from the liquid alloys and ICP analysis. By use of the newly devised cell construction in this study, stable emf values were obtained at each temperature and alloy composition. Emf values were corrected by using the parameter for electronic contribution of the YSZ. Activity of Cr obeys Henry’s law and activity coefficient at infinitely dilute alloys of Cr in Cu-Cr alloys are: lng0 Cr =(3.80 at 1423K, (3.57 at 1473K, (3.38 at 1523K and (3.20 at 1573K. At 1423 K activity coefficient of Zr at infinitely diluted alloy is lnγo Zr = -4.0.

Torque capability improvement of sensorless FOC induction machine in field weakening for propulsion purposes

Directory of Open Access Journals (Sweden)

Nisha G.K.

2017-05-01

Full Text Available An electric propulsion system is generally based on torque controlled electric drive and DC series motors are traditionally used for propulsion system. Induction machines, which are reliable, low cost and have less maintenance, satisfy the characteristics of the propulsion and reinstating the DC series motor. Field oriented control (FOC of induction machines can decouple its torque control from field control which allows the induction motor to act like a separately excited DC motor. In this paper, the characteristic control of induction motor is achieved through appropriate design modification of induction motor by varying magnetizing current to produce maximum torque in field weakening (FW region. Thus to improve the torque capability of induction machine in FW region by varying machine parameters. The sensorless operation of the induction motor is carried out by adopting model reference adaptive system (MRAS using sliding mode control (SMC and a FW algorithm based on the voltage and current constraints. The simulation of the induction motor drive models based on the design options have been carried out and analyzed the simulation results.

ELECTROMOTIVE FORCE, EMF (CELLS)

Energy Technology Data Exchange (ETDEWEB)

Archer, M.D.; Feldberg, S.W.

1998-09-16

The voltage or electric potential difference across the terminals of a cell when no current is drawn from it. The emf of a cell is the sum of the electric potential differences (PDs) produced by a separation of charges (electrons or ions) that can occur at each phase boundary (or interface) in the cell. The magnitude of each PD depends on the chemical nature of the two contacting phases. Thus, at the interface between two different metals, some electrons will have moved from the metal with a higher free energy of electrons to the metal with a lower free energy of electrons. The resultant charge separation will produce a PD (just as charge separation produces a voltage across a capacitor) that, at equilibrium, exactly opposes further electron flow. Similarly, PDs can be produced when electrons partition across a metal/solution interface or metal/solid interface, and when ions partition across a solution/membrane/solution interface.

The Seminole Serpent Warrior At Miramar, FL, Shows Settlement Locations Enabled Environmental Monitoring Reminiscent Of the Four-corners Kokopelli-like EMF Phenomena, and Related to Earthquakes, Tornados and Hurricanes.

Science.gov (United States)

Balam Matagamon, Chan; Pawa Matagamon, Sagamo

2004-03-01

Certain Native Americans of the past seem to have correctly deduced that significant survival information for their tradition-respecting cultures resided in EMF-based phenomena that they were monitoring. This is based upon their myths and the place or cult-hero names they bequeathed us. The sites we have located in FL have been detectable by us visually, usually by faint blue light, or by the elicitation of pin-like prickings, by somewhat intense nervous-system response, by EMF interactions with aural electrochemical systems that can elicit tinitus, and other ways. In the northeast, Cautantowit served as a harbinger of Indian summer, and appears to be another alter ego of the EMF. The Miami, FL Tequesta site along the river clearly correlates with tornado, earthquake and hurricane locations. Sites like the Mohave Deserts giant man may have had similar significance.

Thermodynamic properties of liquid silver-gallium alloys determined from e.m.f. and calorimetric measurements

International Nuclear Information System (INIS)

Jendrzejczyk-Handzlik, Dominika; Fitzner, Krzysztof

2011-01-01

The thermodynamic properties of the liquid Ag-Ga alloys were determined using e.m.f. and calorimetric methods. In the e.m.f. method, solid oxide galvanic cells were used with zirconia electrolyte. The cells of the type W,Ag x Ga (1-x) ,Ga 2 O 3 //ZrO 2 +(Y 2 O 3 )//FeO,Fe,W were used in the temperature range from 1098 K to 1273 K, and in the range of mole fraction from x Ga = 0.1 to x Ga = 1.0. At first, the Gibbs free energy of formation of pure solid gallium oxide, Ga 2 O 3 , from pure elements was derived. Using values of the measured e.m.f. for the cell with x Ga = 1.0, the following temperature dependence was obtained: Δ f G m,Ga 2 O 3 0 (±4kJ·mol -1 J)=-1061.7235+0.2899T/K. Next, the activity of the gallium was derived as a function of the alloy composition from the values of the measured e.m.f. Activities of silver were calculated using the Gibbs-Duhem equation. The drop calorimetric measurements were carried out at two temperatures, viz. 923 K and 1123 K, using a Setaram MHTC calorimeter. Integral enthalpies of mixing of liquid binary alloys were determined at those temperatures. Finally, thermodynamic properties of the liquid alloys were described with the Redlich-Kister equation using ThermoCalc software.

EMF measurements on mixed protonic/electronic conductors for hydrogen membrane applications

DEFF Research Database (Denmark)

Bentzer, Henrik Karnøe; Bonanos, Nikolaos; Phair, John

2010-01-01

Electromotive force (EMF) measurements are often used to estimate the transport number of conducting species in ionic and mixed conductors. In this work, the applicability of the method to systems, where both protonic, oxide-ionic and electronic conduction is significant, was examined. The effect...

Model-Based Motion Tracking of Infants

DEFF Research Database (Denmark)

Olsen, Mikkel Damgaard; Herskind, Anna; Nielsen, Jens Bo

2014-01-01

Even though motion tracking is a widely used technique to analyze and measure human movements, only a few studies focus on motion tracking of infants. In recent years, a number of studies have emerged focusing on analyzing the motion pattern of infants, using computer vision. Most of these studies...... are based on 2D images, but few are based on 3D information. In this paper, we present a model-based approach for tracking infants in 3D. The study extends a novel study on graph-based motion tracking of infants and we show that the extension improves the tracking results. A 3D model is constructed...

A novel Back EMF observer for sensorless control of Interior Permanent Magnet Synchronous Motors

DEFF Research Database (Denmark)

Rasmussen, Henrik; Vadstrup, P.

2005-01-01

The paper presents a position sensing method for IPM motors based on an observer referring to the estimated frame of reference, eliminating problems with position dependent inductances. Convergence of the estimation error to zero is proofed, under the assumption that the mechanical time constant ...

Example-based human motion denoising.

Science.gov (United States)

Lou, Hui; Chai, Jinxiang

2010-01-01

With the proliferation of motion capture data, interest in removing noise and outliers from motion capture data has increased. In this paper, we introduce an efficient human motion denoising technique for the simultaneous removal of noise and outliers from input human motion data. The key idea of our approach is to learn a series of filter bases from precaptured motion data and use them along with robust statistics techniques to filter noisy motion data. Mathematically, we formulate the motion denoising process in a nonlinear optimization framework. The objective function measures the distance between the noisy input and the filtered motion in addition to how well the filtered motion preserves spatial-temporal patterns embedded in captured human motion data. Optimizing the objective function produces an optimal filtered motion that keeps spatial-temporal patterns in captured motion data. We also extend the algorithm to fill in the missing values in input motion data. We demonstrate the effectiveness of our system by experimenting with both real and simulated motion data. We also show the superior performance of our algorithm by comparing it with three baseline algorithms and to those in state-of-art motion capture data processing software such as Vicon Blade.

Emf, maximum power and efficiency of fuel cells

International Nuclear Information System (INIS)

Gaggioli, R.A.; Dunbar, W.R.

1990-01-01

This paper discusses the ideal voltage of steady-flow fuel cells usually expressed by Emf = -ΔG/nF where ΔG is the Gibbs free energy of reaction for the oxidation of the fuel at the supposed temperature of operation of the cell. Furthermore, the ideal power of the cell is expressed as the product of the fuel flow rate with this emf, and the efficiency of a real fuel cell, sometimes called the Gibbs efficiency, is defined as the ratio of the actual power output to this ideal power. Such viewpoints are flawed in several respects. While it is true that if a cell operates isothermally the maximum conceivable work output is equal to the difference between the Gibbs free energy of the incoming reactants and that of the leaving products, nevertheless, even if the cell operates isothermally, the use of the conventional ΔG of reaction assumes that the products of reaction leave separately from one another (and from any unused fuel), and when ΔS of reaction is positive it assumes that a free heat source exists at the operating temperature, whereas if ΔS is negative it neglects the potential power which theoretically could be obtained form the heat released during oxidation. Moreover, the usual cell does not operate isothermally but (virtually) adiabatically

Sensor-less control of the methanol concentration of direct methanol fuel cells at varying ambient temperatures

International Nuclear Information System (INIS)

An, Myung-Gi; Mehmood, Asad; Ha, Heung Yong

2014-01-01

Highlights: • A new algorithm is proposed for the sensor-less control of methanol concentration. • Two different strategies are used depending on the ambient temperatures. • Energy efficiency of the DMFC system has been improved by using the new algorithm. - Abstract: A new version of an algorithm is used to control the methanol concentration in the feed of DMFC systems without using methanol sensors under varying ambient temperatures. The methanol concentration is controlled indirectly by controlling the temperature of the DMFC stack, which correlates well with the methanol concentration. Depending on the ambient temperature relative to a preset reference temperature, two different strategies are used to control the stack temperature: either reducing the cooling rate of the methanol solution passing through an anode-side heat exchanger; or, lowering the pumping rate of the pure methanol to the depleted feed solution. The feasibility of the algorithm is evaluated using a DMFC system that consists of a 200 W stack and the balance of plant (BOP). The DMFC system includes a sensor-less methanol controller that is operated using a LabView system as the central processing unit. The algorithm is experimentally confirmed to precisely control the methanol concentration and the stack temperature at target values under an environment of varying ambient temperatures

Radio-frequency electromagnetic field (RF-EMF) exposure levels in different European outdoor urban environments in comparison with regulatory limits.

Science.gov (United States)

Urbinello, Damiano; Joseph, Wout; Huss, Anke; Verloock, Leen; Beekhuizen, Johan; Vermeulen, Roel; Martens, Luc; Röösli, Martin

2014-07-01

Concerns of the general public about potential adverse health effects caused by radio-frequency electromagnetic fields (RF-EMFs) led authorities to introduce precautionary exposure limits, which vary considerably between regions. It may be speculated that precautionary limits affect the base station network in a manner that mean population exposure unintentionally increases. The objectives of this multicentre study were to compare mean exposure levels in outdoor areas across four different European cities and to compare with regulatory RF-EMF exposure levels in the corresponding areas. We performed measurements in the cities of Amsterdam (the Netherlands, regulatory limits for mobile phone base station frequency bands: 41-61 V/m), Basel (Switzerland, 4-6 V/m), Ghent (Belgium, 3-4.5 V/m) and Brussels (Belgium, 2.9-4.3 V/m) using a portable measurement device. Measurements were conducted in three different types of outdoor areas (central and non-central residential areas and downtown), between 2011 and 2012 at 12 different days. On each day, measurements were taken every 4s for approximately 15 to 30 min per area. Measurements per urban environment were repeated 12 times during 1 year. Arithmetic mean values for mobile phone base station exposure ranged between 0.22 V/m (Basel) and 0.41 V/m (Amsterdam) in all outdoor areas combined. The 95th percentile for total RF-EMF exposure varied between 0.46 V/m (Basel) and 0.82 V/m (Amsterdam) and the 99th percentile between 0.81 V/m (Basel) and 1.20 V/m (Brussels). All exposure levels were far below international reference levels proposed by ICNIRP (International Commission on Non-Ionizing Radiation Protection). Our study did not find indications that lowering the regulatory limit results in higher mobile phone base station exposure levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

MotionExplorer: exploratory search in human motion capture data based on hierarchical aggregation.

Science.gov (United States)

Bernard, Jürgen; Wilhelm, Nils; Krüger, Björn; May, Thorsten; Schreck, Tobias; Kohlhammer, Jörn

2013-12-01

We present MotionExplorer, an exploratory search and analysis system for sequences of human motion in large motion capture data collections. This special type of multivariate time series data is relevant in many research fields including medicine, sports and animation. Key tasks in working with motion data include analysis of motion states and transitions, and synthesis of motion vectors by interpolation and combination. In the practice of research and application of human motion data, challenges exist in providing visual summaries and drill-down functionality for handling large motion data collections. We find that this domain can benefit from appropriate visual retrieval and analysis support to handle these tasks in presence of large motion data. To address this need, we developed MotionExplorer together with domain experts as an exploratory search system based on interactive aggregation and visualization of motion states as a basis for data navigation, exploration, and search. Based on an overview-first type visualization, users are able to search for interesting sub-sequences of motion based on a query-by-example metaphor, and explore search results by details on demand. We developed MotionExplorer in close collaboration with the targeted users who are researchers working on human motion synthesis and analysis, including a summative field study. Additionally, we conducted a laboratory design study to substantially improve MotionExplorer towards an intuitive, usable and robust design. MotionExplorer enables the search in human motion capture data with only a few mouse clicks. The researchers unanimously confirm that the system can efficiently support their work.

Effects of whole body exposure to extremely low frequency electromagnetic fields (ELF-EMF on serum and liver lipid levels, in the rat

Directory of Open Access Journals (Sweden)

Elias-Viñas David

2007-11-01

Full Text Available Abstract Backgound The effects of extremely low-frequency electromagnetic fields (ELF-EMF on the blood serum and liver lipid concentrations of male Wistar rats were assessed. Methods Animals were exposed to a single stimulation (2 h of ELF-EMF (60 Hz, 2.4 mT or sham-stimulated and thereafter sacrificed at different times (24, 48 or 96 h after beginning the exposure. Results Blood lipids showed, at 48 h stimulated animals, a significant increase of cholesterol associated to high density lipoproteins (HDL-C than those observed at any other studied time. Free fatty acid serum presented at 24 h significant increases in comparison with control group. The other serum lipids, triacylglycerols and total cholesterol did not show differences between groups, at any time evaluated. No statistical differences were shown on total lipids of the liver but total cholesterol was elevated at 24 h with a significant decrease at 96 h (p = 0.026. The ELF-EMF stimulation increased the liver content of lipoperoxides at 24 h. Conclusion Single exposures to ELF-EMF increases the serum values of HDL-C, the liver content of lipoperoxides and decreases total cholesterol of the liver. The mechanisms for the effects of ELF-EMF on lipid metabolism are not well understand yet, but could be associated to the nitric oxide synthase EMF-stimulation.

Synergistic effect of EMF-BEMER-type pulsed weak electromagnetic field and HPMA-bound doxorubicin on mouse EL4 T-cell lymphoma.

Science.gov (United States)

Říhová, Blanka; Etrych, Tomáš; Šírová, Milada; Tomala, Jakub; Ulbrich, Karel; Kovář, Marek

2011-12-01

We have investigated the effects of low-frequency pulsed electromagnetic field (LF-EMF) produced by BEMER device on experimental mouse T-cell lymphoma EL4 growing on conventional and/or athymic (nude) mice. Exposure to EMF-BEMER slowed down the growth of tumor mass and prolonged the survival of experimental animals. The effect was more pronounced in immuno-compromised nude mice compared to conventional ones. Acceleration of tumor growth was never observed. No measurable levels of Hsp 70 or increased levels of specific anti-EL4 antibodies were detected in the serum taken from experimental mice before and at different intervals during the experiment, i.e. before solid tumor appeared, at the time of its aggressive growth, and at the terminal stage of the disease. A significant synergizing antitumor effect was seen when EL4 tumor-bearing mice were simultaneously exposed to EMF-BEMER and treated with suboptimal dose of synthetic HPMA copolymer-based doxorubicin, DOX(HYD)-HPMA. Such a combination may be especially useful for heavily treated patients suffering from advanced tumor and requiring additional aggressive chemotherapy which, however, at that time could represent almost life-threatening way of medication.

Very-low-speed variable-structure control of sensorless induction machine drives without signal injection

DEFF Research Database (Denmark)

Lascu, Christian; Boldea, Ion; Blaabjerg, Frede

2005-01-01

A sensorless induction machine drive is presented, in which the principles of variable-structure control and direct torque control (DTC) are combined to ensure high-performance operation in the steady state and under transient conditions. The drive employs a new torque and flux controller......, the "linear and variable-structure control", which realizes accurate and robust control in a wide speed range. Conventional DTC transient merits are preserved, while the steady-state behavior is significantly improved. The full-order state observer is a sliding-mode one, which does not require the rotor speed...

Performance improvement of sensorless vector control for matrix converter drives using PQR power theory

DEFF Research Database (Denmark)

Lee, Kyo Beum; Blaabjerg, Frede

2007-01-01

This paper presents a new method to improve sensorless performance of matrix converter drives using PQR power transformation. The non-linearity of matrix converter drives such as commutation delay, turn-on and turn-off time of switching device, and on-state switching device voltage drop is modelled...... using PQR transformation and compensated using a reference current control scheme. To eliminate the input current distortion due to the input voltage unbalance, a simple method using PQR transformation is also proposed. The proposed compensation method is applied for high performance induction motor...

Environmental Field Surveys, EMF Rapid Program, Engineering Project No.3

Energy Technology Data Exchange (ETDEWEB)

Enertech Consultants

1996-04-01

The EMF Research and Public Information Dissemination Program (RAPID) includes several engineering research in the area of exposure assessment and source characterization. RAPID engineering project No. 3: ''Environmental Field Surveys'' was performed to obtain information on the levels and characteristics of different environments, for which only limited data were available, especially in comparison to magnetic field data for the residential environment and for electric utility facilities, such as power lines and substations. This project was also to provide information on the contribution of various field sources in the surveyed environments. Magnetic field surveys were performed at four sites for each of five environments: schools, hospitals, office buildings, machine shops, and grocery stores. Of the twenty sites surveyed, 11 were located in the San Francisco Bay Area and 9 in Massachusetts. The surveys used a protocol based on magnetic field measurements and observation of activity patterns, designed to provide estimates of magnetic field exposure by type of people and by type of sources. The magnetic field surveys conducted by this project produced a large amount of data which will form a part of the EMF measurement database Field and exposure data were obtained separately for ''area exposure'' and ''at exposure points''. An exposure point is a location where persons engage in fixed, site specific activities near a local source that creates a significant increase in the area field. The area field is produced by ''area sources'', whose location and field distribution is in general not related to the location of the people in the area.

Correlation-based motion vector processing with adaptive interpolation scheme for motion-compensated frame interpolation.

Science.gov (United States)

Huang, Ai-Mei; Nguyen, Truong

2009-04-01

In this paper, we address the problems of unreliable motion vectors that cause visual artifacts but cannot be detected by high residual energy or bidirectional prediction difference in motion-compensated frame interpolation. A correlation-based motion vector processing method is proposed to detect and correct those unreliable motion vectors by explicitly considering motion vector correlation in the motion vector reliability classification, motion vector correction, and frame interpolation stages. Since our method gradually corrects unreliable motion vectors based on their reliability, we can effectively discover the areas where no motion is reliable to be used, such as occlusions and deformed structures. We also propose an adaptive frame interpolation scheme for the occlusion areas based on the analysis of their surrounding motion distribution. As a result, the interpolated frames using the proposed scheme have clearer structure edges and ghost artifacts are also greatly reduced. Experimental results show that our interpolated results have better visual quality than other methods. In addition, the proposed scheme is robust even for those video sequences that contain multiple and fast motions.

A Two-Level Sensorless MPPT Strategy Using SRF-PLL on a PMSG Wind Energy Conversion System

Directory of Open Access Journals (Sweden)

Amina Echchaachouai

2017-01-01

Full Text Available In this paper, a two-level sensorless Maximum Power Point Tracking (MPPT strategy is presented for a variable speed Wind Energy Conversion System (WECS. The proposed system is composed of a wind turbine, a direct-drive Permanent Magnet Synchronous Generator (PMSG and a three phase controlled rectifier connected to a DC load. The realised generator output power maximization analysis justifies the use of the Field Oriented Control (FOC giving the six Pulse Width Modulation (PWM signals to the active rectifier. The generator rotor speed and position required by the FOC and the sensorless MPPT are estimated using a Synchronous Reference Frame Phase Locked Loop (SRF-PLL. The MPPT strategy used consists of two levels, the first level is a power regulation loop and the second level is an extremum seeking bloc generating the coefficient gathering the turbine characteristics. Experimental results validated on a hardware test setup using a DSP digital board (dSPACE 1104 are presented. Figures illustrating the estimated speed and angle confirm that the SRF-PLL is able to give an estimated speed and angle which closely follow the real ones. Also, the power at the DC load and the power at the generator output indicate that the MPPT gives optimum extracted power. Finally, other results show the effectiveness of the adopted approach in real time applications.

A sensorless control method for capacitor voltage balance and circulating current suppression of modular multilevel converter

DEFF Research Database (Denmark)

Liu, Hui; Ma, Ke; Loh, Poh Chiang

2015-01-01

There are several problems in the Modular Multilevel Converter (MMC), such as the appearance of circulating current, capacitor voltage unbalance and the requirement for a high number of sensors. All these problems will decrease the reliability and raise the cost/uncertainty of using MMC solutions....... As a result, a sensorless control method is proposed in this paper, which targets to improve the performances of MMC in respect to the above mentioned disadvantages: To decrease the cost and simplify the physical implementation, a state observer is proposed and designed to estimate both the capacitor voltages...... and the circulating currents in order to replace the high numbers of sensors. Furthermore, a control method combining the circulating current suppression and the capacitor voltage balancing is conducted based on the proposed state observer. It is concluded that the proposed state observer and control method can...

Effects of four kinds of electromagnetic fields (EMF) with different frequency spectrum bands on ovariectomized osteoporosis in mice.

Science.gov (United States)

Lei, Tao; Li, Feijiang; Liang, Zhuowen; Tang, Chi; Xie, Kangning; Wang, Pan; Dong, Xu; Shan, Shuai; Liu, Juan; Xu, Qiaoling; Luo, Erping; Shen, Guanghao

2017-04-03

Electromagnetic fields (EMF) was considered as a non-invasive modality for treatment of osteoporosis while the effects were diverse with EMF parameters in time domain. In present study, we extended analysis of EMF characteristics from time domain to frequency domain, aiming to investigate effects of four kinds of EMF (LP (1-100 Hz), BP (100-3,000 Hz), HP (3,000-50,000 Hz) and AP (1-50,000 Hz)) on ovariectomized (OVX) osteoporosis (OP) in mice. Forty-eight 3-month-old female BALB/c mice were equally assigned to Sham, OVX, OVX + LP, OVX + BP, OVX + HP and OVX + AP groups (n = 8). After 8-week exposure (3 h/day), LP and BP significantly increased serum bone formation markers and osteogenesis-related gene expressions compared with OVX. Bedsides, LP and BP also slightly increased bone resorption activity compared with OVX, evidenced by increased RANKL/OPG ratio. HP sharply decreased serum bone formation and resporption markers and osteogenesis and osteoclastogenesis related gene expressions compared with OVX. AP had accumulative effects of LP, BP and HP, which significantly increased bone formation and decreased bone resporption activity compared with OVX. As a result, LP, BP and HP exposure did not later deterioration of bone mass, microarchitecture and mechanical strength in OVX mice with OP. However, AP stimulation attenuated OVX-induced bone loss.

The Technique of Changing the Drive Method of Micro Step Drive and Sensorless Drive for Hybrid Stepping Motor

Science.gov (United States)

Yoneda, Makoto; Dohmeki, Hideo

The position control system with the advantage large torque, low vibration, and high resolution can be obtained by the constant current micro step drive applied to hybrid stepping motor. However loss is large, in order not to be concerned with load torque but to control current uniformly. As the one technique of a position control system in which high efficiency is realizable, the same sensorless control as a permanent magnet motor is effective. But, it was the purpose that the control method proposed until now controls speed. Then, this paper proposed changing the drive method of micro step drive and sensorless drive. The change of the drive method was verified from the simulation and the experiment. On no load, it was checked not producing change of a large speed at the time of a change by making electrical angle and carrying out zero reset of the integrator. On load, it was checked that a large speed change arose. The proposed system could change drive method by setting up the initial value of an integrator using the estimated result, without producing speed change. With this technique, the low loss position control system, which employed the advantage of the hybrid stepping motor, has been built.

Overview of EMF 22 U.S. transition scenarios

International Nuclear Information System (INIS)

Fawcett, Allen A.; Calvin, Katherine V.; Chesnaye, Francisco C. de la; Reilly, John M.; Weyant, John P.

2009-01-01

The Energy Modeling Forum 22 study included a set of U.S. transition scenarios designed to bracket a range of potential U.S. climate policy goals. Models from the six teams that participated in this part of the study include models that have been prominently involved in analyzing proposed U.S. climate legislation, as well as models that have been involved in the Climate Change Science Program and other parts of this EMF 22 study. This paper presents an overview of the results from the U.S. transition scenarios, and provides insights into the comparison of results from the participating models. (author)

Development of sensor-less control strategies for grid connected PMSG based variable speed wind energy conversion system with improved power quality features

Energy Technology Data Exchange (ETDEWEB)

Chandra, A. [Quebec Univ., Montreal, PQ (Canada). Dept. of Electrical Engineering

2010-07-01

Interest in renewable energy sources has grown in recent years in response to concerns of increasing pollution levels and depleting fossil fuels. Among renewable energy sources, wind energy generation is the fastest growing technology and one of the most cost-effective and environmental friendly means to generate electricity from renewable sources. Modern wind turbines are ready to be deployed in large scale as a result of recent developments in wind power technology. Variable speed permanent magnet synchronous generators (PMSG) based wind energy conversion systems (WECS) are becoming more popular. The use of a permanent magnet reduces size, cost and weight of overall WECS. In addition, the absence of field winding and its excitation system avoids heat dissipation in the rotor winding, thereby improving overall efficiency of the WECS. This type of configuration is more appropriate for remote locations, particularly for off-shore wind application, where the geared doubly fed induction generator usually requires regular maintenance due to tearing-wearing in brushes, windings and gear box. This presentation discussed the development of sensor-less control strategies for grid connected PMSG based variable speed wind energy conversion system with improved power quality features. A novel adaptive network-based fuzzy inference system was used to estimate the speed and position of variable speed PMSG under fluctuating wind conditions. A novel control strategy was developed for the grid interfacing inverter incorporating power quality improvement features at point of common coupling.

Motion Analysis Based on Invertible Rapid Transform

Directory of Open Access Journals (Sweden)

J. Turan

1999-06-01

Full Text Available This paper presents the results of a study on the use of invertible rapid transform (IRT for the motion estimation in a sequence of images. Motion estimation algorithms based on the analysis of the matrix of states (produced in the IRT calculation are described. The new method was used experimentally to estimate crowd and traffic motion from the image data sequences captured at railway stations and at high ways in large cities. The motion vectors may be used to devise a polar plot (showing velocity magnitude and direction for moving objects where the dominant motion tendency can be seen. The experimental results of comparison of the new motion estimation methods with other well known block matching methods (full search, 2D-log, method based on conventional (cross correlation (CC function or phase correlation (PC function for application of crowd motion estimation are also presented.

qEMF3, a novel QTL for the early-morning flowering trait from wild rice, Oryza officinalis, to mitigate heat stress damage at flowering in rice, O. sativa.

Science.gov (United States)

Hirabayashi, Hideyuki; Sasaki, Kazuhiro; Kambe, Takashi; Gannaban, Ritchel B; Miras, Monaliza A; Mendioro, Merlyn S; Simon, Eliza V; Lumanglas, Patrick D; Fujita, Daisuke; Takemoto-Kuno, Yoko; Takeuchi, Yoshinobu; Kaji, Ryota; Kondo, Motohiko; Kobayashi, Nobuya; Ogawa, Tsugufumi; Ando, Ikuo; Jagadish, Krishna S V; Ishimaru, Tsutomu

2015-03-01

A decline in rice (Oryza sativa L.) production caused by heat stress is one of the biggest concerns resulting from future climate change. Rice spikelets are most susceptible to heat stress at flowering. The early-morning flowering (EMF) trait mitigates heat-induced spikelet sterility at the flowering stage by escaping heat stress during the daytime. We attempted to develop near-isogenic lines (NILs) for EMF in the indica-type genetic background by exploiting the EMF locus from wild rice, O. officinalis (CC genome). A stable quantitative trait locus (QTL) for flower opening time (FOT) was detected on chromosome 3. A QTL was designated as qEMF3 and it shifted FOT by 1.5-2.0 h earlier for cv. Nanjing 11 in temperate Japan and cv. IR64 in the Philippine tropics. NILs for EMF mitigated heat-induced spikelet sterility under elevated temperature conditions completing flower opening before reaching 35°C, a general threshold value leading to spikelet sterility. Quantification of FOT of cultivars popular in the tropics and subtropics did not reveal the EMF trait in any of the cultivars tested, suggesting that qEMF3 has the potential to advance FOT of currently popular cultivars to escape heat stress at flowering under future hotter climates. This is the first report to examine rice with the EMF trait through marker-assisted breeding using wild rice as a genetic resource. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Analyzing locomotion synthesis with feature-based motion graphs.

Science.gov (United States)

Mahmudi, Mentar; Kallmann, Marcelo

2013-05-01

We propose feature-based motion graphs for realistic locomotion synthesis among obstacles. Among several advantages, feature-based motion graphs achieve improved results in search queries, eliminate the need of postprocessing for foot skating removal, and reduce the computational requirements in comparison to traditional motion graphs. Our contributions are threefold. First, we show that choosing transitions based on relevant features significantly reduces graph construction time and leads to improved search performances. Second, we employ a fast channel search method that confines the motion graph search to a free channel with guaranteed clearance among obstacles, achieving faster and improved results that avoid expensive collision checking. Lastly, we present a motion deformation model based on Inverse Kinematics applied over the transitions of a solution branch. Each transition is assigned a continuous deformation range that does not exceed the original transition cost threshold specified by the user for the graph construction. The obtained deformation improves the reachability of the feature-based motion graph and in turn also reduces the time spent during search. The results obtained by the proposed methods are evaluated and quantified, and they demonstrate significant improvements in comparison to traditional motion graph techniques.

Motion Learning Based on Bayesian Program Learning

Directory of Open Access Journals (Sweden)

Cheng Meng-Zhen

2017-01-01

Full Text Available The concept of virtual human has been highly anticipated since the 1980s. By using computer technology, Human motion simulation could generate authentic visual effect, which could cheat human eyes visually. Bayesian Program Learning train one or few motion data, generate new motion data by decomposing and combining. And the generated motion will be more realistic and natural than the traditional one.In this paper, Motion learning based on Bayesian program learning allows us to quickly generate new motion data, reduce workload, improve work efficiency, reduce the cost of motion capture, and improve the reusability of data.

New sensorless, efficient optimized and stabilized v/f control for pmsm machines

Science.gov (United States)

Jafari, Seyed Hesam

With the rapid advances in power electronics and motor drive technologies in recent decades, permanent magnet synchronous machines (PMSM) have found extensive applications in a variety of industrial systems due to its many desirable features such as high power density, high efficiency, and high torque to current ratio, low noise, and robustness. In low dynamic applications like pumps, fans and compressors where the motor speed is nearly constant, usage of a simple control algorithm that can be implemented with least number of the costly external hardware can be highly desirable for industry. In recent published works, for low power PMSMs, a new sensorless volts-per-hertz (V/f) controlling method has been proposed which can be used for PMSM drive applications where the motor speed is constant. Moreover, to minimize the cost of motor implementation, the expensive rotor damper winding was eliminated. By removing the damper winding, however, instability problems normally occur inside of the motor which in some cases can be harmful for a PMSM drive. As a result, to address the instability issue, a stabilizing loop was developed and added to the conventional V/f. By further studying the proposed sensorless stabilized V/f, and calculating power loss, it became known that overall motor efficiency still is needed to be improved and optimized. This thesis suggests a new V/f control method for PMSMs, where both efficiency and stability problems are addressed. Also, although in nearly all recent related research, methods have been applied to low power PMSM, for the first time, in this thesis, the suggested method is implemented for a medium power 15 kW PMSM. A C2000 F2833x Digital Signal Processor (DSP) is used as controller part for the student custom built PMSM drive, but instead of programming the DSP in Assembly or C, the main control algorithm was developed in a rapid prototype software environment which here Matlab Simulink embedded code library is used.

Learning Motion Features for Example-Based Finger Motion Estimation for Virtual Characters

Science.gov (United States)

Mousas, Christos; Anagnostopoulos, Christos-Nikolaos

2017-09-01

This paper presents a methodology for estimating the motion of a character's fingers based on the use of motion features provided by a virtual character's hand. In the presented methodology, firstly, the motion data is segmented into discrete phases. Then, a number of motion features are computed for each motion segment of a character's hand. The motion features are pre-processed using restricted Boltzmann machines, and by using the different variations of semantically similar finger gestures in a support vector machine learning mechanism, the optimal weights for each feature assigned to a metric are computed. The advantages of the presented methodology in comparison to previous solutions are the following: First, we automate the computation of optimal weights that are assigned to each motion feature counted in our metric. Second, the presented methodology achieves an increase (about 17%) in correctly estimated finger gestures in comparison to a previous method.

Robust Non-Linear Direct Torque and Flux Control of Adjustable Speed Sensorless PMSM Drive Based on SVM Using a PI Predictive Controller

Directory of Open Access Journals (Sweden)

F. Naceri

2010-01-01

Full Text Available This paper presents a new sensorless direct torque control method for voltage inverter – fed PMSM. The control methodis used a modified Direct Torque Control scheme with constant inverter switching frequency using Space Vector Modulation(DTC-SVM. The variation of stator and rotor resistance due to changes in temperature or frequency deteriorates theperformance of DTC-SVM controller by introducing errors in the estimated flux linkage and the electromagnetic torque.As a result, this approach will not be suitable for high power drives such as those used in tractions, as they require goodtorque control performance at considerably lower frequency. A novel stator resistance estimator is proposed. The estimationmethod is implemented using the Extended Kalman Filter. Finally extensive simulation results are presented to validate theproposed technique. The system is tested at different speeds and a very satisfactory performance has been achieved.

DIRECT OBSERVATION OF THE TURBULENT emf AND TRANSPORT OF MAGNETIC FIELD IN A LIQUID SODIUM EXPERIMENT

Energy Technology Data Exchange (ETDEWEB)

Rahbarnia, Kian; Brown, Benjamin P.; Clark, Mike M.; Kaplan, Elliot J.; Nornberg, Mark D.; Rasmus, Alex M.; Taylor, Nicholas Zane; Forest, Cary B. [Department of Physics, University of Wisconsin-Madison, 1150 University Ave, Madison, WI 53706 (United States); Jenko, Frank; Limone, Angelo [Max-Planck-Institut fuer Plasmaphysik (IPP), EURATOM Association, D-85748 Garching (Germany); Pinton, Jean-Francois; Plihon, Nicolas; Verhille, Gautier, E-mail: kian.rahbarnia@ipp.mpg.de [Laboratoire de Physique de l' Ecole Normale Superieure de Lyon, CNRS and Universite de Lyon, F-69364 Lyon (France)

2012-11-10

For the first time, we have directly measured the transport of a vector magnetic field by isotropic turbulence in a high Reynolds number liquid metal flow. In analogy with direct measurements of the turbulent Reynolds stress (turbulent viscosity) that governs momentum transport, we have measured the turbulent electromotive force (emf) by simultaneously measuring three components of velocity and magnetic fields, and computed the correlations that lead to mean-field current generation. Furthermore, we show that this turbulent emf tends to oppose and cancel out the local current, acting to increase the effective resistivity of the medium, i.e., it acts as an enhanced magnetic diffusivity. This has important implications for turbulent transport in astrophysical objects, particularly in dynamos and accretion disks.

DIRECT OBSERVATION OF THE TURBULENT emf AND TRANSPORT OF MAGNETIC FIELD IN A LIQUID SODIUM EXPERIMENT

International Nuclear Information System (INIS)

Rahbarnia, Kian; Brown, Benjamin P.; Clark, Mike M.; Kaplan, Elliot J.; Nornberg, Mark D.; Rasmus, Alex M.; Taylor, Nicholas Zane; Forest, Cary B.; Jenko, Frank; Limone, Angelo; Pinton, Jean-François; Plihon, Nicolas; Verhille, Gautier

2012-01-01

For the first time, we have directly measured the transport of a vector magnetic field by isotropic turbulence in a high Reynolds number liquid metal flow. In analogy with direct measurements of the turbulent Reynolds stress (turbulent viscosity) that governs momentum transport, we have measured the turbulent electromotive force (emf) by simultaneously measuring three components of velocity and magnetic fields, and computed the correlations that lead to mean-field current generation. Furthermore, we show that this turbulent emf tends to oppose and cancel out the local current, acting to increase the effective resistivity of the medium, i.e., it acts as an enhanced magnetic diffusivity. This has important implications for turbulent transport in astrophysical objects, particularly in dynamos and accretion disks.

Sensorless State-Space Control of Elastic Two-Inertia Drive System Using a Minimum State Order Observer

Directory of Open Access Journals (Sweden)

V. Comnac

2009-12-01

Full Text Available The paper presents sensorless state-space control of two-inertia drive system with resilient coupling. The control structure contains an I+PI controller for load speed regulation and a state feedback controller for effective vibration suppression of the elastic coupling. Mechanical state variable of two-inertia drive are obtained by using a linear minimum-order (Gopinath state observer. The design of the combined (I+PI and state feedback controller is achieved with the extended version of the modulus criterion [5]. The dynamic behavior of presented control structure has been examined, for different conditions, using MATLAB/SIMULINK simulation.

Sensorless Reserved Power Control Strategy for Two-Stage Grid-Connected Photovoltaic Systems

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

2016-01-01

Due to still increasing penetration level of grid-connected Photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A reserved power control, where the active power from the PV panels is reserved during operation, is required for grid...... support. In this paper, a cost-effective solution to realize the reserved power control for grid-connected PV systems is proposed. The proposed solution routinely employs a Maximum Power Point Tracking (MPPT) control to estimate the available PV power and a Constant Power Generation (CPG) control...... to achieve the power reserve. In this method, the irradiance measurements that have been used in conventional control schemes to estimate the available PV power are not required, and thereby being a sensorless solution. Simulations and experimental tests have been performed on a 3-kW two-stage single...

Predictive local receptive fields based respiratory motion tracking for motion-adaptive radiotherapy.

Science.gov (United States)

Yubo Wang; Tatinati, Sivanagaraja; Liyu Huang; Kim Jeong Hong; Shafiq, Ghufran; Veluvolu, Kalyana C; Khong, Andy W H

2017-07-01

Extracranial robotic radiotherapy employs external markers and a correlation model to trace the tumor motion caused by the respiration. The real-time tracking of tumor motion however requires a prediction model to compensate the latencies induced by the software (image data acquisition and processing) and hardware (mechanical and kinematic) limitations of the treatment system. A new prediction algorithm based on local receptive fields extreme learning machines (pLRF-ELM) is proposed for respiratory motion prediction. All the existing respiratory motion prediction methods model the non-stationary respiratory motion traces directly to predict the future values. Unlike these existing methods, the pLRF-ELM performs prediction by modeling the higher-level features obtained by mapping the raw respiratory motion into the random feature space of ELM instead of directly modeling the raw respiratory motion. The developed method is evaluated using the dataset acquired from 31 patients for two horizons in-line with the latencies of treatment systems like CyberKnife. Results showed that pLRF-ELM is superior to that of existing prediction methods. Results further highlight that the abstracted higher-level features are suitable to approximate the nonlinear and non-stationary characteristics of respiratory motion for accurate prediction.

Example-Based Automatic Music-Driven Conventional Dance Motion Synthesis

Energy Technology Data Exchange (ETDEWEB)

Xu, Songhua [ORNL; Fan, Rukun [University of North Carolina, Chapel Hill; Geng, Weidong [Zhejiang University

2011-04-21

We introduce a novel method for synthesizing dance motions that follow the emotions and contents of a piece of music. Our method employs a learning-based approach to model the music to motion mapping relationship embodied in example dance motions along with those motions' accompanying background music. A key step in our method is to train a music to motion matching quality rating function through learning the music to motion mapping relationship exhibited in synchronized music and dance motion data, which were captured from professional human dance performance. To generate an optimal sequence of dance motion segments to match with a piece of music, we introduce a constraint-based dynamic programming procedure. This procedure considers both music to motion matching quality and visual smoothness of a resultant dance motion sequence. We also introduce a two-way evaluation strategy, coupled with a GPU-based implementation, through which we can execute the dynamic programming process in parallel, resulting in significant speedup. To evaluate the effectiveness of our method, we quantitatively compare the dance motions synthesized by our method with motion synthesis results by several peer methods using the motions captured from professional human dancers' performance as the gold standard. We also conducted several medium-scale user studies to explore how perceptually our dance motion synthesis method can outperform existing methods in synthesizing dance motions to match with a piece of music. These user studies produced very positive results on our music-driven dance motion synthesis experiments for several Asian dance genres, confirming the advantages of our method.

Example-based automatic music-driven conventional dance motion synthesis.

Science.gov (United States)

Fan, Rukun; Xu, Songhua; Geng, Weidong

2012-03-01

We introduce a novel method for synthesizing dance motions that follow the emotions and contents of a piece of music. Our method employs a learning-based approach to model the music to motion mapping relationship embodied in example dance motions along with those motions' accompanying background music. A key step in our method is to train a music to motion matching quality rating function through learning the music to motion mapping relationship exhibited in synchronized music and dance motion data, which were captured from professional human dance performance. To generate an optimal sequence of dance motion segments to match with a piece of music, we introduce a constraint-based dynamic programming procedure. This procedure considers both music to motion matching quality and visual smoothness of a resultant dance motion sequence. We also introduce a two-way evaluation strategy, coupled with a GPU-based implementation, through which we can execute the dynamic programming process in parallel, resulting in significant speedup. To evaluate the effectiveness of our method, we quantitatively compare the dance motions synthesized by our method with motion synthesis results by several peer methods using the motions captured from professional human dancers' performance as the gold standard. We also conducted several medium-scale user studies to explore how perceptually our dance motion synthesis method can outperform existing methods in synthesizing dance motions to match with a piece of music. These user studies produced very positive results on our music-driven dance motion synthesis experiments for several Asian dance genres, confirming the advantages of our method.

Full-order Luenberger observer based on fuzzy-logic control for sensorless field-oriented control of a single-sided linear induction motor.

Science.gov (United States)

Holakooie, Mohammad Hosein; Ojaghi, Mansour; Taheri, Asghar

2016-01-01

This paper investigates sensorless indirect field oriented control (IFOC) of SLIM with full-order Luenberger observer. The dynamic equations of SLIM are first elaborated to draw full-order Luenberger observer with some simplifying assumption. The observer gain matrix is derived from conventional procedure so that observer poles are proportional to SLIM poles to ensure the stability of system for wide range of linear speed. The operation of observer is significantly impressed by adaptive scheme. A fuzzy logic control (FLC) is proposed as adaptive scheme to estimate linear speed using speed tuning signal. The parameters of FLC are tuned using an off-line method through chaotic optimization algorithm (COA). The performance of the proposed observer is verified by both numerical simulation and real-time hardware-in-the-loop (HIL) implementation. Moreover, a detailed comparative study among proposed and other speed observers is obtained under different operation conditions. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

MRAS speed estimator with fuzzy and PI stator resistance adaptation for sensorless induction motor drives using RT-lab

Directory of Open Access Journals (Sweden)

S. Mohan Krishna

2016-09-01

Full Text Available This paper presents a real-time simulation study of Model Reference Adaptive System based rotor speed estimator with parallel stator resistance adaptation mechanism for speed sensorless induction motor drive. Both, the traditional Proportional Integral and Fuzzy logic based control mechanisms are utilised for stator resistance adaptation, while, the rotor speed is estimated parallely by means of Proportional Integral based mechanism. The estimator's response to dynamic changes in Load perturbation and doubling of the nominal value of the actual stator resistance of the motor is observed. The superiority of the fuzzy based stator resistance adaptation in the Model Reference Adaptive System estimator is proved through results validated in real-time. The purpose of employing a fairly new real-time platform is to reduce the test and prototype time. The model is initially built using Matlab/Simulink blocksets and the results are validated in real time using RT-Lab. The RT-lab blocksets are integrated into the Simulink model and then executed in real-time using the OP-4500 target developed by Opal-RT. The real-time simulation results are observed in the workstation.

A large-scale measurement of electromagnetic fields near GSM base stations in Guangxi, China for risk communication.

Science.gov (United States)

Wu, Tongning; Shao, Qing; Yang, Lei; Qi, Dianyuan; Lin, Jun; Lin, Xiaojun; Yu, Zongying

2013-06-01

Radiofrequency (RF) electromagnetic field (EMF) exposure from wireless telecommunication base station antennae can lead to debates, conflicts or litigations among the adjacent residents if inappropriately managed. This paper presents a measurement campaign for the GSM band EMF exposure in the vicinity of 827 base station sites (totally 6207 measurement points) in Guangxi, China. Measurement specifications are designed for risk communication with the residents who previously complained of over-exposure. The EMF power densities with the global positioning system coordinate at each measured point were recorded. Compliance with the International Commission on Non-Ionizing Radiation Protection guidelines and Chinese environmental EMF safety standards was studied. The results show that the GSM band EMF level near the base stations is very low. The measurement results and the EMF risk communication procedures positively influence public perception of the RF EMF exposure from the base stations and promote the exchange of EMF exposure-related knowledge.

A Two-stage Kalman Filter for Sensorless Direct Torque Controlled PM Synchronous Motor Drive

Directory of Open Access Journals (Sweden)

Boyu Yi

2013-01-01

Full Text Available This paper presents an optimal two-stage extended Kalman filter (OTSEKF for closed-loop flux, torque, and speed estimation of a permanent magnet synchronous motor (PMSM to achieve sensorless DTC-SVPWM operation of drive system. The novel observer is obtained by using the same transformation as in a linear Kalman observer, which is proposed by C.-S. Hsieh and F.-C. Chen in 1999. The OTSEKF is an effective implementation of the extended Kalman filter (EKF and provides a recursive optimum state estimation for PMSMs using terminal signals that may be polluted by noise. Compared to a conventional EKF, the OTSEKF reduces the number of arithmetic operations. Simulation and experimental results verify the effectiveness of the proposed OTSEKF observer for DTC of PMSMs.

Nepal and the Americas: Can Electromagnetic Field (EMF) Signals Be Detected There That Yield Information About Culturally Dictated Spiritual Values, and Can Computers Interface Their Assessment?

Science.gov (United States)

Aryal, Sanjita; Mc Leod, Roger D.; Mc Leod, David M.

2002-10-01

Nepal has a particularly rich tradition of culturally developed views on the material and spiritual worlds, and also has a powerful natural environment that may generate EMFs in conjunction with natural phenomena. We have an interest in determining whether these can be detected by portable technological means, and recording such data on notebook-type computers for analysis and evaluation. One goal is to assess whether historic Native Americans, such as Maine's and New Hampshire's Molly Ockett, may have been motivated in their selection of special, and perhaps, to them, "sacred" sites for their attention and as possible burial sites. Some of these may have been chosen on the basis of the EMFs that seem to emanate from them, and their assessment of what they meant to their worldviews. Do some Amerindians consider the EMF and reincarnation as requiring their rejection of material aspects of existence? Could other traditional cultures, or even suicidal terrorists, be sensitive to "information" they may receive from the EMF?

A large-scale measurement of electromagnetic fields near GSM base stations in Guangxi, China for risk communication

International Nuclear Information System (INIS)

Wu, T.; Shao, Q.; Yang, L.; Qi, D.; Lin, J.; Lin, X.; Yu, Z.

2013-01-01

Radiofrequency (RF) electromagnetic field (EMF) exposure from wireless telecommunication base station antennae can lead to debates, conflicts or litigations among the adjacent residents if inappropriately managed. This paper presents a measurement campaign for the GSM band EMF exposure in the vicinity of 827 base station sites (totally 6207 measurement points) in Guangxi, China. Measurement specifications are designed for risk communication with the residents who previously complained of over-exposure. The EMF power densities with the global positioning system coordinate at each measured point were recorded. Compliance with the International Commission on Non-Ionizing Radiation Protection guidelines and Chinese environmental EMF safety standards was studied. The results show that the GSM band EMF level near the base stations is very low. The measurement results and the EMF risk communication procedures positively influence public perception of the RF EMF exposure from the base stations and promote the exchange of EMF exposure-related knowledge. (authors)

Sensorless Stator Field-Oriented Controlled IM Drive at Low Speed with Rr Estimator

Directory of Open Access Journals (Sweden)

Wen-Cheng Pu

2014-01-01

Full Text Available This paper pertains to a technique of a sensorless indirect stator field-oriented induction motor control, which prevents the accumulative errors incurred by the integrator and the problem relating to the stability of the control system caused by the stator resistance susceptible to temperature variations while conducting the flux estimation directly and computing the synchronous rotary speed. The research adds an adaptive flux observer to estimate the speed of the rotor and uses the fixed trace algorithm (FTA to execute an online estimation of the slip difference, thereby improving the system of stability under the low rotary speed at regenerating mode and the influence of the rotor resistance on the slip angle. Finally, the paper conducts simulations by Simulink of MATLAB and practices to verify the correctness of the result the paper presents.

Retraction: Evaluation of carcinogenic effects of electromagnetic fields (EMF).

Science.gov (United States)

Mehic, Bakir

2010-11-01

The Editor-in-chief of the Bosnian Journal of Basic Medical Sciences has decided to retract the article from Bayazit V et al. [1] entitled as: "Evaluation of carcinogenic effects of electromagnetic fields (EMF)" published in Bosn J Basic Med Sci. 2010 Aug;10(3):245-50. After the editorial office was alerted of possible plagiarism in the article, it conducted thorough investigation and concluded that the article apparently represents plagiarized material from two World Health Organization reports, one European Commission report and other sources. Since this is considered scientific plagiarism and scientific misconduct, Editor-in-chief has decided to withdraw the article. The authors have agreed with the editorial office decision.

Design and fabrication of a microplatform for the proximity effect study of localized ELF-EMF on the growth of in vitro HeLa and PC-12 cells

International Nuclear Information System (INIS)

Chen, Y C; Chen, C C; Cheng, Y T; Tu, W; Tseng, F G

2010-01-01

This paper presents a platform technology with experimental results that show the scientists and biologists a way to rapidly investigate and analyze the biological effects of localized extremely low frequency (ELF) electromagnetic field (EMF) on living cells. The proximity effect of the localized ELF-EMF on living cells is revealed using the bio-compatible microplatform on which an on-glass inductive coil array, the source of the localized ELF-EMF in micro scale, is designed, fabricated and operated with a field strength of 1.2 ± 0.1 mT at 60 Hz for cell culturing study. After a 72 h ELF-EMF exposure, HeLa (human cervical cancer) and PC-12 (rat pheochromocytoma) cells exhibit about 18.4% and 12.9% cell proliferation rate reduction, respectively. Furthermore, according to the presented dynamic model, the reduction of the proliferation can be attributed to the interference of signal transduction processes due to the tangential currents induced around the cells

Investigation of micronuclei induction in human peripheral blood lymphocytes exposed in vitro to EMF RF

International Nuclear Information System (INIS)

Kolomiets, Irina A.; Triapitsina, Galina A.; Polevik, Nikolai D.; Pryakhin, Evgeny A.

2008-01-01

Full text: The widespread application of cellular phones is of great concern in view possible consequences for human health. The aim of this study is to assess the capability of electromagnetic fields (EMF) RF with frequency 925 MHz and modulation 217 Hz to induce genotoxic effects as evaluated by the in vitro micronucleus assay on peripheral blood lymphocytes. The flasks of peripheral blood samples collected from healthy volunteers (5 men and 5 women) were placed just on the oscillator of emitting antenna. The signals were produced by the laboratory research plant and were evaluated at four specific absorption rates (SARs) - 0; 0.29; 1.2; 8.1 W/kg. SARs were determined by the calorimetric method. Phytohaemagglutinin stimulated lymphocytes were exposed three times for 10 minutes in the G o (the first 30 minutes after the beginning of cultivation), S (24 hours later), G 2 -M (after 48 hours from the beginning of cultivation) stages of the cell cycle. 72-hours cultures of lymphocytes were examined to determine the extent of micronuclei. The Mann-Whitney U-test was used to evaluate the significance for comparison. The data indicated a significant increase of micronuclei in human lymphocytes exposed to EMF RF (6.5 ± 0.51 0/00; 7.1 ± 0.66 0/00; 7.0 ± 0.50 0/00) in comparison with sham-exposed lymphocytes (3.0 ± 0.60 0/00). There was not revealed a dose-dependent increase of micronuclei in human lymphocytes. It was suggested that the increase of micronuclei in lymphocytes is explicated by a particularity of EMF RF just near the oscillator of emitting antenna. (author)

Unsupervised motion-based object segmentation refined by color

Science.gov (United States)

Piek, Matthijs C.; Braspenning, Ralph; Varekamp, Chris

2003-06-01

For various applications, such as data compression, structure from motion, medical imaging and video enhancement, there is a need for an algorithm that divides video sequences into independently moving objects. Because our focus is on video enhancement and structure from motion for consumer electronics, we strive for a low complexity solution. For still images, several approaches exist based on colour, but these lack in both speed and segmentation quality. For instance, colour-based watershed algorithms produce a so-called oversegmentation with many segments covering each single physical object. Other colour segmentation approaches exist which somehow limit the number of segments to reduce this oversegmentation problem. However, this often results in inaccurate edges or even missed objects. Most likely, colour is an inherently insufficient cue for real world object segmentation, because real world objects can display complex combinations of colours. For video sequences, however, an additional cue is available, namely the motion of objects. When different objects in a scene have different motion, the motion cue alone is often enough to reliably distinguish objects from one another and the background. However, because of the lack of sufficient resolution of efficient motion estimators, like the 3DRS block matcher, the resulting segmentation is not at pixel resolution, but at block resolution. Existing pixel resolution motion estimators are more sensitive to noise, suffer more from aperture problems or have less correspondence to the true motion of objects when compared to block-based approaches or are too computationally expensive. From its tendency to oversegmentation it is apparent that colour segmentation is particularly effective near edges of homogeneously coloured areas. On the other hand, block-based true motion estimation is particularly effective in heterogeneous areas, because heterogeneous areas improve the chance a block is unique and thus decrease the

On a PCA-based lung motion model

Energy Technology Data Exchange (ETDEWEB)

Li Ruijiang; Lewis, John H; Jia Xun; Jiang, Steve B [Department of Radiation Oncology and Center for Advanced Radiotherapy Technologies, University of California San Diego, 3855 Health Sciences Dr, La Jolla, CA 92037-0843 (United States); Zhao Tianyu; Wuenschel, Sara; Lamb, James; Yang Deshan; Low, Daniel A [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Pl, St. Louis, MO 63110-1093 (United States); Liu Weifeng, E-mail: sbjiang@ucsd.edu [Amazon.com Inc., 701 5th Ave. Seattle, WA 98104 (United States)

2011-09-21

Respiration-induced organ motion is one of the major uncertainties in lung cancer radiotherapy and is crucial to be able to accurately model the lung motion. Most work so far has focused on the study of the motion of a single point (usually the tumor center of mass), and much less work has been done to model the motion of the entire lung. Inspired by the work of Zhang et al (2007 Med. Phys. 34 4772-81), we believe that the spatiotemporal relationship of the entire lung motion can be accurately modeled based on principle component analysis (PCA) and then a sparse subset of the entire lung, such as an implanted marker, can be used to drive the motion of the entire lung (including the tumor). The goal of this work is twofold. First, we aim to understand the underlying reason why PCA is effective for modeling lung motion and find the optimal number of PCA coefficients for accurate lung motion modeling. We attempt to address the above important problems both in a theoretical framework and in the context of real clinical data. Second, we propose a new method to derive the entire lung motion using a single internal marker based on the PCA model. The main results of this work are as follows. We derived an important property which reveals the implicit regularization imposed by the PCA model. We then studied the model using two mathematical respiratory phantoms and 11 clinical 4DCT scans for eight lung cancer patients. For the mathematical phantoms with cosine and an even power (2n) of cosine motion, we proved that 2 and 2n PCA coefficients and eigenvectors will completely represent the lung motion, respectively. Moreover, for the cosine phantom, we derived the equivalence conditions for the PCA motion model and the physiological 5D lung motion model (Low et al 2005 Int. J. Radiat. Oncol. Biol. Phys. 63 921-9). For the clinical 4DCT data, we demonstrated the modeling power and generalization performance of the PCA model. The average 3D modeling error using PCA was within 1

On a PCA-based lung motion model.

Science.gov (United States)

Li, Ruijiang; Lewis, John H; Jia, Xun; Zhao, Tianyu; Liu, Weifeng; Wuenschel, Sara; Lamb, James; Yang, Deshan; Low, Daniel A; Jiang, Steve B

2011-09-21

Respiration-induced organ motion is one of the major uncertainties in lung cancer radiotherapy and is crucial to be able to accurately model the lung motion. Most work so far has focused on the study of the motion of a single point (usually the tumor center of mass), and much less work has been done to model the motion of the entire lung. Inspired by the work of Zhang et al (2007 Med. Phys. 34 4772-81), we believe that the spatiotemporal relationship of the entire lung motion can be accurately modeled based on principle component analysis (PCA) and then a sparse subset of the entire lung, such as an implanted marker, can be used to drive the motion of the entire lung (including the tumor). The goal of this work is twofold. First, we aim to understand the underlying reason why PCA is effective for modeling lung motion and find the optimal number of PCA coefficients for accurate lung motion modeling. We attempt to address the above important problems both in a theoretical framework and in the context of real clinical data. Second, we propose a new method to derive the entire lung motion using a single internal marker based on the PCA model. The main results of this work are as follows. We derived an important property which reveals the implicit regularization imposed by the PCA model. We then studied the model using two mathematical respiratory phantoms and 11 clinical 4DCT scans for eight lung cancer patients. For the mathematical phantoms with cosine and an even power (2n) of cosine motion, we proved that 2 and 2n PCA coefficients and eigenvectors will completely represent the lung motion, respectively. Moreover, for the cosine phantom, we derived the equivalence conditions for the PCA motion model and the physiological 5D lung motion model (Low et al 2005 Int. J. Radiat. Oncol. Biol. Phys. 63 921-9). For the clinical 4DCT data, we demonstrated the modeling power and generalization performance of the PCA model. The average 3D modeling error using PCA was within 1

On a PCA-based lung motion model

International Nuclear Information System (INIS)

Li Ruijiang; Lewis, John H; Jia Xun; Jiang, Steve B; Zhao Tianyu; Wuenschel, Sara; Lamb, James; Yang Deshan; Low, Daniel A; Liu Weifeng

2011-01-01

Respiration-induced organ motion is one of the major uncertainties in lung cancer radiotherapy and is crucial to be able to accurately model the lung motion. Most work so far has focused on the study of the motion of a single point (usually the tumor center of mass), and much less work has been done to model the motion of the entire lung. Inspired by the work of Zhang et al (2007 Med. Phys. 34 4772-81), we believe that the spatiotemporal relationship of the entire lung motion can be accurately modeled based on principle component analysis (PCA) and then a sparse subset of the entire lung, such as an implanted marker, can be used to drive the motion of the entire lung (including the tumor). The goal of this work is twofold. First, we aim to understand the underlying reason why PCA is effective for modeling lung motion and find the optimal number of PCA coefficients for accurate lung motion modeling. We attempt to address the above important problems both in a theoretical framework and in the context of real clinical data. Second, we propose a new method to derive the entire lung motion using a single internal marker based on the PCA model. The main results of this work are as follows. We derived an important property which reveals the implicit regularization imposed by the PCA model. We then studied the model using two mathematical respiratory phantoms and 11 clinical 4DCT scans for eight lung cancer patients. For the mathematical phantoms with cosine and an even power (2n) of cosine motion, we proved that 2 and 2n PCA coefficients and eigenvectors will completely represent the lung motion, respectively. Moreover, for the cosine phantom, we derived the equivalence conditions for the PCA motion model and the physiological 5D lung motion model (Low et al 2005 Int. J. Radiat. Oncol. Biol. Phys. 63 921-9). For the clinical 4DCT data, we demonstrated the modeling power and generalization performance of the PCA model. The average 3D modeling error using PCA was within 1

Sensorless Speed Control of Permanent Magnet Synchronous Motors by Neural Network Algorithm

Directory of Open Access Journals (Sweden)

Ming-Shyan Wang

2014-01-01

Full Text Available The sliding mode control has the merits with respect to the variation of the disturbance and robustness. In this paper, the sensorless sliding-mode observer with least mean squared error approach for permanent magnet synchronous motor (PMSM to detect the rotor position by counter electromotive force and then compute motor speed is designed and implemented. In addition, the neural network control is also used to compensate the PI gain tuning to increase the speed accuracy without regarding the errors of the current measurement and motor noise. In this paper, a digital signal processor TMS320F2812 utilizes its high-speed ADC module to get current feedback information and thus to estimate the rotor position and takes advantage of the built-in modules to achieve SVPWM current control so that the senseless speed control will be accomplished. The correctness and effectiveness of the proposed control system will be verified from the experimental results.

Sensorless Sinusoidal Drives for Fan and Pump Motors by V/f Control

Science.gov (United States)

Kiuchi, Mitsuyuki; Ohnishi, Tokuo

This paper proposes sensorless sinusoidal driving methods of permanent magnet synchronous motors for fans and pumps by V/f control. The proposed methods are simple methods that control the motor peak current constant by voltage or frequency control, and are characterized by DC link current detection using a single shunt resistor at carrier wave signal bottom timing. As a result of the dumping factor from square torque load characteristics of fan and pump motors, it is possible to control stable starting and stable steady state by V/f control. In general, pressure losses as a result of the fluid pass of fan and pump systems are nearly constant; therefore, the flow rate and motor torque are determined by revolutions. Accordingly, high efficiency driving is possible by setting corresponding currents to q-axis currents (torque currents) at target revolutions. Because of the simple current detection and motor control methods, the proposed methods are optimum for fan and pump motor driving systems of home appliances.

Automatic Video-based Analysis of Human Motion

DEFF Research Database (Denmark)

Fihl, Preben

The human motion contains valuable information in many situations and people frequently perform an unconscious analysis of the motion of other people to understand their actions, intentions, and state of mind. An automatic analysis of human motion will facilitate many applications and thus has...... received great interest from both industry and research communities. The focus of this thesis is on video-based analysis of human motion and the thesis presents work within three overall topics, namely foreground segmentation, action recognition, and human pose estimation. Foreground segmentation is often...... the first important step in the analysis of human motion. By separating foreground from background the subsequent analysis can be focused and efficient. This thesis presents a robust background subtraction method that can be initialized with foreground objects in the scene and is capable of handling...

Music recommendation according to human motion based on kernel CCA-based relationship

Science.gov (United States)

Ohkushi, Hiroyuki; Ogawa, Takahiro; Haseyama, Miki

2011-12-01

In this article, a method for recommendation of music pieces according to human motions based on their kernel canonical correlation analysis (CCA)-based relationship is proposed. In order to perform the recommendation between different types of multimedia data, i.e., recommendation of music pieces from human motions, the proposed method tries to estimate their relationship. Specifically, the correlation based on kernel CCA is calculated as the relationship in our method. Since human motions and music pieces have various time lengths, it is necessary to calculate the correlation between time series having different lengths. Therefore, new kernel functions for human motions and music pieces, which can provide similarities between data that have different time lengths, are introduced into the calculation of the kernel CCA-based correlation. This approach effectively provides a solution to the conventional problem of not being able to calculate the correlation from multimedia data that have various time lengths. Therefore, the proposed method can perform accurate recommendation of best matched music pieces according to a target human motion from the obtained correlation. Experimental results are shown to verify the performance of the proposed method.

TU-F-BRB-00: MRI-Based Motion Management for RT

International Nuclear Information System (INIS)

2015-01-01

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has high temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant

TU-F-BRB-00: MRI-Based Motion Management for RT

Energy Technology Data Exchange (ETDEWEB)

NONE

2015-06-15

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has high temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.

Ground-based transmission line conductor motion sensor

International Nuclear Information System (INIS)

Jacobs, M.L.; Milano, U.

1988-01-01

A ground-based-conductor motion-sensing apparatus is provided for remotely sensing movement of electric-power transmission lines, particularly as would occur during the wind-induced condition known as galloping. The apparatus is comprised of a motion sensor and signal-generating means which are placed underneath a transmission line and will sense changes in the electric field around the line due to excessive line motion. The detector then signals a remote station when a conditioning of galloping is sensed. The apparatus of the present invention is advantageous over the line-mounted sensors of the prior art in that it is easier and less hazardous to install. The system can also be modified so that a signal will only be given when particular conditions, such as specific temperature range, large-amplitude line motion, or excessive duration of the line motion, are occurring

Design of Parameter Independent, High Performance Sensorless Controllers for Permanent Magnet Synchronous Machines

DEFF Research Database (Denmark)

Xie, Ge

. The transient fluctuation of the estimated rotor position error is around 20 degrees with a step load torque change from 0% to 100% of the rated torque. The position error in steady state is within ±2 electrical degrees for the best case. The proposed method may also be used for e.g. online machine parameter......The Permanent Magnet Synchronous Machine (PMSM) has become an attractive candidate for various industrial applications due to its high efficiency and torque density. In the PMSM drive system, simple and robust control methods play an important role in achieving satisfactory drive performances....... For reducing the cost and increasing the reliability of the drive system, eliminating the mechanical sensor brings a lot advantages to the PMSM drive system. Therefore, sensorless control was developed and has been increasingly used in different PMSM drive systems in the last 20 years. However, machine...

Base response arising from free-field motions

International Nuclear Information System (INIS)

Whitley, J.R.; Morgan, J.R.; Hall, W.J.; Newmark, N.M.

1977-01-01

A procedure is illustrated in this paper for deriving (estimating) from a free-field record the horizontal base motions of a building, including horizontal rotation and translation. More specifically the goal was to compare results of response calculations based on derived accelerations with the results of calculations based on recorded accelerations. The motions are determined by assuming that an actual recorded ground wave transits a rigid base of a given dimension. Calculations given in the paper were made employing the earthquake acceleration time histories of the Hollywood storage building and the adjacent P.E. lot for the Kern County (1952) and San Fernando (1971) earthquakes. (Auth.)

Direct catalytic transformation of carbohydrates into 5-ethoxymethylfurfural with acid–base bifunctional hybrid nanospheres

International Nuclear Information System (INIS)

Li, Hu; Govind, Khokarale Santosh; Kotni, Ramakrishna; Shunmugavel, Saravanamurugan; Riisager, Anders; Yang, Song

2014-01-01

Graphical abstract: Catalytic conversion of carbohydrates into HMF and EMF in ethanol/DMSO with acid–base bifunctional hybrid nanospheres prepared from self-assembly of corresponding basic amino acids and HPA. - Highlights: • Acid–base bifunctional nanospheres were efficient for production of EMF from sugars. • Synthesis of EMF in a high yield of 76.6% was realized from fructose. • Fructose based biopolymers could also be converted into EMF with good yields. • Ethyl glucopyranoside was produced in good yields from glucose in ethanol. - Abstract: A series of acid–base bifunctional hybrid nanospheres prepared from the self-assembly of basic amino acids and phosphotungstic acid (HPA) with different molar ratios were employed as efficient and recyclable catalysts for synthesis of liquid biofuel 5-ethoxymethylfurfural (EMF) from various carbohydrates. A high EMF yield of 76.6%, 58.5%, 42.4%, and 36.5% could be achieved, when fructose, inulin, sorbose, and sucrose were used as starting materials, respectively. Although, the acid–base bifunctional nanocatalysts were inert for synthesis of EMF from glucose based carbohydrates, ethyl glucopyranoside in good yields could be obtained from glucose in ethanol. Moreover, the nanocatalyst functionalized with acid and basic sites was able to be reused several times with no significant loss in catalytic activity

Simulation and Implementation of Sensorless Control in Multi-Motors Electric Drives with High Dynamics

Directory of Open Access Journals (Sweden)

Marcel Nicola

2017-05-01

Full Text Available In this article we’ll tackle the control of multi-motors electric drives with high dynamic, with rapid changes in torque and speed, with rigid or flexible coupling of motors, where the control strategy is FOC (Field Oriented Control for each drives and the distributed control in local network using the CANopen protocol. In the surface mining industry, from which the electric drive application for this article is selected, the general trend is toward using asynchronous motors with short-circuit rotor, due to the advantages of this motor both in terms of design and operation. In order to achieve the variable speed, must be used the static frequency converters with sensorless control, where speed is estimated using a Model References Adaptive Control Estimator. The global control system proposed in this paper contain this type of MRAC estimator together with PI-control based, who ensures a good dynamic performance but in a lower complexity of structure such that are properly to implement in real time in a distributed control system with DSP in local network using the CANopen protocol with advantages in terms of software technology, as well as control cost and flexibility of use. Following these directions a functional application was implemented and tested in practice.

Modal-pushover-based ground-motion scaling procedure

Science.gov (United States)

Kalkan, Erol; Chopra, Anil K.

2011-01-01

Earthquake engineering is increasingly using nonlinear response history analysis (RHA) to demonstrate the performance of structures. This rigorous method of analysis requires selection and scaling of ground motions appropriate to design hazard levels. This paper presents a modal-pushover-based scaling (MPS) procedure to scale ground motions for use in a nonlinear RHA of buildings. In the MPS method, the ground motions are scaled to match to a specified tolerance, a target value of the inelastic deformation of the first-mode inelastic single-degree-of-freedom (SDF) system whose properties are determined by the first-mode pushover analysis. Appropriate for first-mode dominated structures, this approach is extended for structures with significant contributions of higher modes by considering elastic deformation of second-mode SDF systems in selecting a subset of the scaled ground motions. Based on results presented for three actual buildings-4, 6, and 13-story-the accuracy and efficiency of the MPS procedure are established and its superiority over the ASCE/SEI 7-05 scaling procedure is demonstrated.

Scaling earthquake ground motions for performance-based assessment of buildings

Science.gov (United States)

Huang, Y.-N.; Whittaker, A.S.; Luco, N.; Hamburger, R.O.

2011-01-01

The impact of alternate ground-motion scaling procedures on the distribution of displacement responses in simplified structural systems is investigated. Recommendations are provided for selecting and scaling ground motions for performance-based assessment of buildings. Four scaling methods are studied, namely, (1)geometric-mean scaling of pairs of ground motions, (2)spectrum matching of ground motions, (3)first-mode-period scaling to a target spectral acceleration, and (4)scaling of ground motions per the distribution of spectral demands. Data were developed by nonlinear response-history analysis of a large family of nonlinear single degree-of-freedom (SDOF) oscillators that could represent fixed-base and base-isolated structures. The advantages and disadvantages of each scaling method are discussed. The relationship between spectral shape and a ground-motion randomness parameter, is presented. A scaling procedure that explicitly considers spectral shape is proposed. ?? 2011 American Society of Civil Engineers.

Universal "Imaginary Closed Circuit Method" and Formula for Determination of Direction of Induced EMF/Current

Science.gov (United States)

Atram, Dattatraya Balaram

2011-01-01

Fleming's right-hand rule and the right-flat-hand rule are generally applied for determining the direction of flow of induced emf/current in straight conductors. The right-hand-fingers rule is applied for coils only. The right-hand-thumb rule can be applied for either straight conductors or coils. Different rules have to be applied for different…

Speed Sensorless vector control of parallel-connected three-phase two-motor single-inverter drive system

DEFF Research Database (Denmark)

Gunabalan, Ramachandiran; Sanjeevikumar, Padmanaban; Blaabjerg, Frede

2016-01-01

to noise and parameter uncertainty. The gain matrix is absent in the natural observer. The rotor speed is estimated from the load torque, stator current, and rotor flux. Under symmetrical load conditions, the difference in speed between two induction motors is reduced by considering the motor parameters......This paper presents the characteristic behavior of direct vector control of two induction motors with sensorless speed feedback having the same rating parameters, paralleled combination, and supplied from a single current-controlled pulse-width-modulated voltage-source inverter drive. Natural...... observer design technique is known for its simple construction, which estimates the speed and rotor fluxes. Load torque is estimated by load torque adaptation and the average rotor flux was maintained constant by rotor flux feedback control. The technique’s convergence rate is very fast and is robust...

Perception of mobile phone and base station risks.

Science.gov (United States)

Siegrist, Michael; Earle, Timothy C; Gutscher, Heinz; Keller, Carmen

2005-10-01

Perceptions of risks associated with mobile phones, base stations, and other sources of electromagnetic fields (EMF) were examined. Data from a telephone survey conducted in the German- and French-speaking parts of Switzerland are presented (N = 1,015). Participants assessed both risks and benefits associated with nine different sources of EMF. Trust in the authorities regulating these hazards was assessed as well. In addition, participants answered a set of questions related to attitudes toward EMF and toward mobile phone base stations. According to respondents' assessments, high-voltage transmission lines are the most risky source of EMF. Mobile phones and mobile phone base stations received lower risk ratings. Results showed that trust in authorities was positively associated with perceived benefits and negatively associated with perceived risks. People who use their mobile phones frequently perceived lower risks and higher benefits than people who use their mobile phones infrequently. People who believed they lived close to a base station did not significantly differ in their level of risks associated with mobile phone base stations from people who did not believe they lived close to a base station. Regarding risk regulation, a majority of participants were in favor of fixing limiting values based on the worst-case scenario. Correlations suggest that belief in paranormal phenomena is related to level of perceived risks associated with EMF. Furthermore, people who believed that most chemical substances cause cancer also worried more about EMF than people who did not believe that chemical substances are that harmful. Practical implications of the results are discussed.

Sensorless displacement estimation of a shape memory alloy coil spring actuator using inductance

International Nuclear Information System (INIS)

Kim, Hongjip; Lee, Dae-young; Cho, Kyu-Jin; Han, Yongsu; Ha, Jung-Ik

2013-01-01

To measure the displacement of a shape memory alloy (SMA) coil spring actuator for feedback control, displacement sensors larger than the actuator are normally required. In this study, a novel method for estimating the displacement of an SMA coil spring actuator without a sensor is proposed. Instead of a sensor, coil inductance is used for estimating the displacement. Coil inductance is estimated by measuring the voltage and the transient response of the current. It has a one-to-one relationship with the displacement of the coil and is not affected by load. Previous methods for estimating displacement using resistance measurements are heavily affected by load variations. The experimental results herein show that displacement is estimated with reasonable accuracy under varying loads using coil inductance. This sensorless method of estimating the displacement of an SMA coil spring actuator can be used to build a compact feedback controller because there is no need for a bulky displacement sensor. (paper)

Maximum torque per ampere control of sensorless induction motor drives with dc offset and parameter compensation

International Nuclear Information System (INIS)

Markadeh, Gholamreza Arab; Hajian, Masood; Soltani, Jafar; Hosseinia, Saeed

2010-01-01

Field orientation control of induction machine (IM) drives is a well-known strategy which has a fast dynamic response. In this paper, the direct rotor flux field orientation control of speed sensorless IM drive is presented. A two level space vector modulation inverter is employed to generate the command stator voltage. In proposed control scheme, a maximum torque per ampere strategy is achieved using a so-called fast flux search method. Based on this method, for a given load torque and rotor speed, the magnitude of rotor reference flux is adjusted step by step until the effective value of stator current becomes minimized finally. In addition, using the IM fifth order model in the stationary reference frame, a nonlinear rotor flux observer is developed which is also capable of motor resistances and rotor speed simultaneously estimation. Moreover, a useful method is introduced for dc offset compensation which is a major problem of ac drives especially at low speeds. The proposed control idea is experimentally implemented in real time using a CPLD board synchronized with a personal computer. Simulation and experimental results are finally presented to confirm the validity and effectiveness of the proposed method.

Retraction: Evaluation of Carcinogenic Effects of Electromagnetic Fields (Emf

Directory of Open Access Journals (Sweden)

Bakir Mehic

2010-08-01

Full Text Available This retracts the article "EVALUATION OF CARCINOGENIC EFFECTS OF ELECTROMAGNETIC FIELDS (EMF" on page 245. The Editor-in-chief of the Bosnian Journal ofBasic Medical Sciences has decided to retract the article from Bayazit V et al. [1] entitled as: “Evaluation of carcinogenic effects of electromagnetic fields (EMF” published in Bosn J Basic Med Sci. 2010 Aug;10(3:245-50.After the editorial office was alerted of possible plagiarism in the article, it conducted thorough investigation and concluded that the article apparently represents plagiarized material from two World Health Organization reports, one European Commission report and other sources. Since this is considered scientific plagiarism and scientific misconduct, Editor-in-chief has decided to withdraw the article. The authors have agreed with the editorial office decision.

Thermo-emf of cadmium under hydrostatic pressure up to 3.0 GPa in the range of electron-topological transition

International Nuclear Information System (INIS)

Krajdenov, V.F.; Itskevich, E.S.; Gapotchenko, A.G.

1995-01-01

Dependence of longitudinal d and transverse α thermo-emf of cadmium in 4-300 K temperature range at pressures up to 3.0 GPa was investigated. The anomaly value depends sufficiently on sample perfection

TU-F-BRB-03: Clinical Implementation of MR-Based Motion Management

International Nuclear Information System (INIS)

Glide-Hurst, C.

2015-01-01

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has high temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant

TU-F-BRB-03: Clinical Implementation of MR-Based Motion Management

Energy Technology Data Exchange (ETDEWEB)

Glide-Hurst, C. [Henry Ford Health System (United States)

2015-06-15

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has high temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.

Avaliação quantitativa da movimentação parietal regional do ventrículo esquerdo na endomiocardiofibrose Quantitative assessment of left ventricular regional wall motion in endomyocardial fibrosis

Directory of Open Access Journals (Sweden)

Charles Mady

2005-03-01

motion in patients with endomyocardial fibrosis (EMF. METHODS: The study comprised 88 patients, 59 of the female sex, with a mean age of 39±13 years (range, 9 to 65 and with echocardiographic and angiographic evidence of left ventricular EMF. The intensity of fibrous tissue buildup on contrast cineventriculography was classified as mild, moderate, or severe. The overall left ventricular ejection fraction (LVEF was determined by using the area-length method on ventriculography. The motion was measured in 100 equidistant chords perpendicular to the centerline drawn in the middle of the final diastolic and systolic contours and normalized to cardiac size. Five left ventricular segments were analyzed: A - apical; AL - anterolateral; AB - anterobasal; IA - inferoapical; IB - inferobasal. Abnormality was expressed in units of standard deviation of the mean motion in a normal population of reference, comprised of 103 patients with normal LV according to clinical and electrocardiographic data, and angiographic standards. RESULTS: Mean LVEF was 0.47±0.12. Fibrous tissue buildup in the left ventricle was mild in 12 patients, moderate in 40, and severe in 36. The regions with the poorest ventricular wall motion were A (-1.4±1.6 standard deviation/chords and IA (-1.6±1.8 standard deviation/chords compared with that in AB (-0.3±1.9 standard deviation/chords, AL (-0.5±1.8 standard deviation/chords and IB (-0.9±1.3 standard deviation/chords. No relation was observed between the intensity of fibrous tissue buildup and regional ventricular wall motion. CONCLUSION: A change in LV regional wall motion exists in EMF, and it is independent of the intensity of fibrous tissue buildup qualitatively assessed. Nonuniform involvement of the LV should be considered when planning surgery for this disease.

RF EMF Risk Perception Revisited: Is the Focus on Concern Sufficient for Risk Perception Studies?

Science.gov (United States)

Wiedemann, Peter M; Freudenstein, Frederik; Böhmert, Christoph; Wiart, Joe; Croft, Rodney J

2017-06-08

An implicit assumption of risk perception studies is that concerns expressed in questionnaires reflect concerns in everyday life. The aim of the present study is to check this assumption, i.e., the extrapolability of risk perceptions expressed in a survey, to risk perceptions in everyday life. To that end, risk perceptions were measured by a multidimensional approach. In addition to the traditional focus on measuring the magnitude of risk perceptions, the thematic relevance (how often people think about a risk issue) and the discursive relevance (how often people think about or discuss a risk issue) of risk perceptions were also collected. Taking into account this extended view of risk perception, an online survey was conducted in six European countries with 2454 respondents, referring to radio frequency electromagnetic field (RF EMF) risk potentials from base stations, and access points, such as WiFi routers and cell phones. The findings reveal that the present study's multidimensional approach to measuring risk perception provides a more differentiated understanding of RF EMF risk perception. High levels of concerns expressed in questionnaires do not automatically imply that these concerns are thematically relevant in everyday life. We use thematic relevance to distinguish between enduringly concerned (high concern according to both questionnaire and thematic relevance) and not enduringly concerned participants (high concern according to questionnaire but no thematic relevance). Furthermore, we provide data for the empirical value of this distinction: Compared to other participants, enduringly concerned subjects consider radio frequency electromagnetic field exposure to a greater extent as a moral and affective issue. They also see themselves as highly exposed to radio frequency electromagnetic fields. However, despite these differences, subjects with high levels of thematic relevance are nevertheless sensitive to exposure reduction as a means for improving the

RF EMF Risk Perception Revisited: Is the Focus on Concern Sufficient for Risk Perception Studies?

Science.gov (United States)

Wiedemann, Peter M.; Freudenstein, Frederik; Böhmert, Christoph; Wiart, Joe; Croft, Rodney J.

2017-01-01

An implicit assumption of risk perception studies is that concerns expressed in questionnaires reflect concerns in everyday life. The aim of the present study is to check this assumption, i.e., the extrapolability of risk perceptions expressed in a survey, to risk perceptions in everyday life. To that end, risk perceptions were measured by a multidimensional approach. In addition to the traditional focus on measuring the magnitude of risk perceptions, the thematic relevance (how often people think about a risk issue) and the discursive relevance (how often people think about or discuss a risk issue) of risk perceptions were also collected. Taking into account this extended view of risk perception, an online survey was conducted in six European countries with 2454 respondents, referring to radio frequency electromagnetic field (RF EMF) risk potentials from base stations, and access points, such as WiFi routers and cell phones. The findings reveal that the present study’s multidimensional approach to measuring risk perception provides a more differentiated understanding of RF EMF risk perception. High levels of concerns expressed in questionnaires do not automatically imply that these concerns are thematically relevant in everyday life. We use thematic relevance to distinguish between enduringly concerned (high concern according to both questionnaire and thematic relevance) and not enduringly concerned participants (high concern according to questionnaire but no thematic relevance). Furthermore, we provide data for the empirical value of this distinction: Compared to other participants, enduringly concerned subjects consider radio frequency electromagnetic field exposure to a greater extent as a moral and affective issue. They also see themselves as highly exposed to radio frequency electromagnetic fields. However, despite these differences, subjects with high levels of thematic relevance are nevertheless sensitive to exposure reduction as a means for improving the

A Force Sensorless Method for CFRP/Ti Stack Interface Detection during Robotic Orbital Drilling Operations

Directory of Open Access Journals (Sweden)

Qiang Fang

2015-01-01

Full Text Available Drilling carbon fiber reinforced plastics and titanium (CFRP/Ti stacks is one of the most important activities in aircraft assembly. It is favorable to use different drilling parameters for each layer due to their dissimilar machining properties. However, large aircraft parts with changing profiles lead to variation of thickness along the profiles, which makes it challenging to adapt the cutting parameters for different materials being drilled. This paper proposes a force sensorless method based on cutting force observer for monitoring the thrust force and identifying the drilling material during the drilling process. The cutting force observer, which is the combination of an adaptive disturbance observer and friction force model, is used to estimate the thrust force. An in-process algorithm is developed to monitor the variation of the thrust force for detecting the stack interface between the CFRP and titanium materials. Robotic orbital drilling experiments have been conducted on CFRP/Ti stacks. The estimate error of the cutting force observer was less than 13%, and the stack interface was detected in 0.25 s (or 0.05 mm before or after the tool transited it. The results show that the proposed method can successfully detect the CFRP/Ti stack interface for the cutting parameters adaptation.

Experimental study for sensorless broken bar detection in induction motors

International Nuclear Information System (INIS)

Calis, Hakan; Cakir, Abduelkadir

2008-01-01

This study presents experimental results of sensorless broken bar detection in induction motors based on fluctuations of the stator current zero crossing instants before actual breakdown occurs. These fluctuations are sensed by a microcontroller (μC), and transferred to a computer for monitoring the amplitude changes on specific frequency components using fast Fourier transformation algorithms. The motor current signal is also monitored for verification purposes. The main reasons of rotor faults are broken bars, end ring faults and bearing faults. Most recent efforts are focusing on current spectrum analysis, as the current signal is easily accessible for all induction motors. Instead of sampling motor current with a high resolution analog to digital converter, zero crossing instants are recorded as the waveforms cross zero. Fluctuations in the intervals between successive zero crossings of the three phase current waveforms are analyzed in the frequency domain. Broken bars and end ring breakages, supply unbalances, rotor eccentricities and shaft misalignment faults are distinguished by monitoring amplitude changes of the 2sf, f r , and 2f spectral components, where s is the motor slip, f is supply frequency and f r is rotor speed. Appearance of only the 2sf component in zero crossing times (ZCT) of the signal spectrum implies rotor faults. The 2f component occurs only when supply is unbalanced or in the case of stator winding faults. Separation of these two faults is implemented by monitoring both components. In addition, when there is additional rotor eccentricity due to bearing deterioration or shaft misalignment, it is also necessary to monitor the f r fault signature component to distinguish mixed faults. It may be necessary to include additional signals such as motor vibration or temperature to extend the reliability of the fault detection system for critical machines

Knee Motion Generation Method for Transfemoral Prosthesis Based on Kinematic Synergy and Inertial Motion.

Science.gov (United States)

Sano, Hiroshi; Wada, Takahiro

2017-12-01

Previous research has shown that the effective use of inertial motion (i.e., less or no torque input at the knee joint) plays an important role in achieving a smooth gait of transfemoral prostheses in the swing phase. In our previous research, a method for generating a timed knee trajectory close to able-bodied individuals, which leads to sufficient clearance between the foot and the floor and the knee extension, was proposed using the inertial motion. Limb motions are known to correlate with each other during walking. This phenomenon is called kinematic synergy. In this paper, we measure gaits in level walking of able-bodied individuals with a wide range of walking velocities. We show that this kinematic synergy also exists between the motions of the intact limbs and those of the knee as determined by the inertial motion technique. We then propose a new method for generating the motion of the knee joint using its inertial motion close to the able-bodied individuals in mid-swing based on its kinematic synergy, such that the method can adapt to the changes in the motion velocity. The numerical simulation results show that the proposed method achieves prosthetic walking similar to that of able-bodied individuals with a wide range of constant walking velocities and termination of walking from steady-state walking. Further investigations have found that a kinematic synergy also exists at the start of walking. Overall, our method successfully achieves knee motion generation from the initiation of walking through steady-state walking with different velocities until termination of walking.

Active contour-based visual tracking by integrating colors, shapes, and motions.

Science.gov (United States)

Hu, Weiming; Zhou, Xue; Li, Wei; Luo, Wenhan; Zhang, Xiaoqin; Maybank, Stephen

2013-05-01

In this paper, we present a framework for active contour-based visual tracking using level sets. The main components of our framework include contour-based tracking initialization, color-based contour evolution, adaptive shape-based contour evolution for non-periodic motions, dynamic shape-based contour evolution for periodic motions, and the handling of abrupt motions. For the initialization of contour-based tracking, we develop an optical flow-based algorithm for automatically initializing contours at the first frame. For the color-based contour evolution, Markov random field theory is used to measure correlations between values of neighboring pixels for posterior probability estimation. For adaptive shape-based contour evolution, the global shape information and the local color information are combined to hierarchically evolve the contour, and a flexible shape updating model is constructed. For the dynamic shape-based contour evolution, a shape mode transition matrix is learnt to characterize the temporal correlations of object shapes. For the handling of abrupt motions, particle swarm optimization is adopted to capture the global motion which is applied to the contour in the current frame to produce an initial contour in the next frame.

Non-specific physical symptoms in relation to actual and perceived exposure to electromagnetic fields (EMF) : A multidisciplinary approach

NARCIS (Netherlands)

Baliatsas, C.

2015-01-01

The association between non-specific physical symptoms (NSPS) such as headache, fatigue, nausea and sleep problems and exposure to electromagnetic fields (EMF) in the general population has been a subject of ongoing scientific debate and public concern. A limited number of epidemiological studies

Image-based motion compensation for high-resolution extremities cone-beam CT

Science.gov (United States)

Sisniega, A.; Stayman, J. W.; Cao, Q.; Yorkston, J.; Siewerdsen, J. H.; Zbijewski, W.

2016-03-01

Purpose: Cone-beam CT (CBCT) of the extremities provides high spatial resolution, but its quantitative accuracy may be challenged by involuntary sub-mm patient motion that cannot be eliminated with simple means of external immobilization. We investigate a two-step iterative motion compensation based on a multi-component metric of image sharpness. Methods: Motion is considered with respect to locally rigid motion within a particular region of interest, and the method supports application to multiple locally rigid regions. Motion is estimated by maximizing a cost function with three components: a gradient metric encouraging image sharpness, an entropy term that favors high contrast and penalizes streaks, and a penalty term encouraging smooth motion. Motion compensation involved initial coarse estimation of gross motion followed by estimation of fine-scale displacements using high resolution reconstructions. The method was evaluated in simulations with synthetic motion (1-4 mm) applied to a wrist volume obtained on a CMOS-based CBCT testbench. Structural similarity index (SSIM) quantified the agreement between motion-compensated and static data. The algorithm was also tested on a motion contaminated patient scan from dedicated extremities CBCT. Results: Excellent correction was achieved for the investigated range of displacements, indicated by good visual agreement with the static data. 10-15% improvement in SSIM was attained for 2-4 mm motions. The compensation was robust against increasing motion (4% decrease in SSIM across the investigated range, compared to 14% with no compensation). Consistent performance was achieved across a range of noise levels. Significant mitigation of artifacts was shown in patient data. Conclusion: The results indicate feasibility of image-based motion correction in extremities CBCT without the need for a priori motion models, external trackers, or fiducials.

FPGA-Based Real-Time Motion Detection for Automated Video Surveillance Systems

Directory of Open Access Journals (Sweden)

Sanjay Singh

2016-03-01

Full Text Available Design of automated video surveillance systems is one of the exigent missions in computer vision community because of their ability to automatically select frames of interest in incoming video streams based on motion detection. This research paper focuses on the real-time hardware implementation of a motion detection algorithm for such vision based automated surveillance systems. A dedicated VLSI architecture has been proposed and designed for clustering-based motion detection scheme. The working prototype of a complete standalone automated video surveillance system, including input camera interface, designed motion detection VLSI architecture, and output display interface, with real-time relevant motion detection capabilities, has been implemented on Xilinx ML510 (Virtex-5 FX130T FPGA platform. The prototyped system robustly detects the relevant motion in real-time in live PAL (720 × 576 resolution video streams directly coming from the camera.

A novel method for estimating the initial rotor position of PM motors without the position sensor

International Nuclear Information System (INIS)

Rostami, Alireza; Asaei, Behzad

2009-01-01

Permanent magnet (PM) motors have been used widely in the industrial applications. However, a need of the position sensor is a drawback of their control system. The sensorless methods using the back-EMF (electromotive force) cannot detect the rotor position at a standstill; recently, a few methods proposed to detect the initial rotor position, but they have high estimation error which reduces starting torque of the motor. Therefore, in this paper, a novel method to detect the initial rotor position of the PM motors is proposed, first, by using a space vector model, response of the stator current space vector to the saturation of the stator core is analyzed; then a novel method based on the saturation effect is presented that estimates the initial rotor position and the maximum estimation error is less than 3.8 deg. Simulation results confirm this method is effective and precise, and variation of the motor parameters does not affect its precision.

A novel method for estimating the initial rotor position of PM motors without the position sensor

Energy Technology Data Exchange (ETDEWEB)

Rostami, Alireza; Asaei, Behzad [School of Electrical and Computer Engineering, Faculty of Engineering, University of Tehran, Tehran (Iran)

2009-08-15

Permanent magnet (PM) motors have been used widely in the industrial applications. However, a need of the position sensor is a drawback of their control system. The sensorless methods using the back-EMF (electromotive force) cannot detect the rotor position at a standstill; recently, a few methods proposed to detect the initial rotor position, but they have high estimation error which reduces starting torque of the motor. Therefore, in this paper, a novel method to detect the initial rotor position of the PM motors is proposed, first, by using a space vector model, response of the stator current space vector to the saturation of the stator core is analyzed; then a novel method based on the saturation effect is presented that estimates the initial rotor position and the maximum estimation error is less than 3.8. Simulation results confirm this method is effective and precise, and variation of the motor parameters does not affect its precision. (author)

Vibration-based damage detection in wind turbine blades using Phase-based Motion Estimation and motion magnification

Science.gov (United States)

Sarrafi, Aral; Mao, Zhu; Niezrecki, Christopher; Poozesh, Peyman

2018-05-01

Vibration-based Structural Health Monitoring (SHM) techniques are among the most common approaches for structural damage identification. The presence of damage in structures may be identified by monitoring the changes in dynamic behavior subject to external loading, and is typically performed by using experimental modal analysis (EMA) or operational modal analysis (OMA). These tools for SHM normally require a limited number of physically attached transducers (e.g. accelerometers) in order to record the response of the structure for further analysis. Signal conditioners, wires, wireless receivers and a data acquisition system (DAQ) are also typical components of traditional sensing systems used in vibration-based SHM. However, instrumentation of lightweight structures with contact sensors such as accelerometers may induce mass-loading effects, and for large-scale structures, the instrumentation is labor intensive and time consuming. Achieving high spatial measurement resolution for a large-scale structure is not always feasible while working with traditional contact sensors, and there is also the potential for a lack of reliability associated with fixed contact sensors in outliving the life-span of the host structure. Among the state-of-the-art non-contact measurements, digital video cameras are able to rapidly collect high-density spatial information from structures remotely. In this paper, the subtle motions from recorded video (i.e. a sequence of images) are extracted by means of Phase-based Motion Estimation (PME) and the extracted information is used to conduct damage identification on a 2.3-m long Skystream® wind turbine blade (WTB). The PME and phased-based motion magnification approach estimates the structural motion from the captured sequence of images for both a baseline and damaged test cases on a wind turbine blade. Operational deflection shapes of the test articles are also quantified and compared for the baseline and damaged states. In addition

Review of Studies Concerning Electromagnetic Field (EMF Exposure Assessment in Europe: Low Frequency Fields (50 Hz–100 kHz

Directory of Open Access Journals (Sweden)

Peter Gajšek

2016-09-01

Full Text Available We aimed to review the findings of exposure assessment studies done in European countries on the exposure of the general public to low frequency electric and magnetic fields (EMFs of various frequencies. The study shows that outdoor average extremely low frequency magnetic fields (ELF-MF in public areas in urban environments range between 0.05 and 0.2 µT in terms of flux densities, but stronger values (of the order of a few µT may occur directly beneath high-voltage power lines, at the walls of transformer buildings, and at the boundary fences of substations. In the indoor environment, high values have been measured close to several domestic appliances (up to the mT range, some of which are held close to the body, e.g., hair dryers, electric shavers. Common sources of exposure to intermediate frequencies (IF include induction cookers, compact fluorescent lamps, inductive charging systems for electric cars and security or anti-theft devices. No systematic measurement surveys or personal exposimetry data for the IF range have been carried out and only a few reports on measurements of EMFs around such devices are mentioned. According to the available European exposure assessment studies, three population exposure categories were classified by the authors regarding the possible future risk analysis. This classification should be considered a crucial advancement for exposure assessment, which is a mandatory step in any future health risk assessment of EMFs exposure.

Review of Studies Concerning Electromagnetic Field (EMF) Exposure Assessment in Europe: Low Frequency Fields (50 Hz–100 kHz)

Science.gov (United States)

Gajšek, Peter; Ravazzani, Paolo; Grellier, James; Samaras, Theodoros; Bakos, József; Thuróczy, György

2016-01-01

We aimed to review the findings of exposure assessment studies done in European countries on the exposure of the general public to low frequency electric and magnetic fields (EMFs) of various frequencies. The study shows that outdoor average extremely low frequency magnetic fields (ELF-MF) in public areas in urban environments range between 0.05 and 0.2 µT in terms of flux densities, but stronger values (of the order of a few µT) may occur directly beneath high-voltage power lines, at the walls of transformer buildings, and at the boundary fences of substations. In the indoor environment, high values have been measured close to several domestic appliances (up to the mT range), some of which are held close to the body, e.g., hair dryers, electric shavers. Common sources of exposure to intermediate frequencies (IF) include induction cookers, compact fluorescent lamps, inductive charging systems for electric cars and security or anti-theft devices. No systematic measurement surveys or personal exposimetry data for the IF range have been carried out and only a few reports on measurements of EMFs around such devices are mentioned. According to the available European exposure assessment studies, three population exposure categories were classified by the authors regarding the possible future risk analysis. This classification should be considered a crucial advancement for exposure assessment, which is a mandatory step in any future health risk assessment of EMFs exposure. PMID:27598182

A video-based system for hand-driven stop-motion animation.

Science.gov (United States)

Han, Xiaoguang; Fu, Hongbo; Zheng, Hanlin; Liu, Ligang; Wang, Jue

2013-01-01

Stop-motion is a well-established animation technique but is often laborious and requires craft skills. A new video-based system can animate the vast majority of everyday objects in stop-motion style, more flexibly and intuitively. Animators can perform and capture motions continuously instead of breaking them into increments and shooting one still picture per increment. More important, the system permits direct hand manipulation without resorting to rigs, achieving more natural object control for beginners. The system's key component is two-phase keyframe-based capturing and processing, assisted by computer vision techniques. With this system, even amateurs can generate high-quality stop-motion animations.

Radio-frequency electromagnetic field (RF-EMF) exposure levels in different European outdoor urban environments in comparison with regulatory limits

NARCIS (Netherlands)

Urbinello, Damiano; Joseph, Wout; Huss, Anke|info:eu-repo/dai/nl/331385880; Verloock, Leen; Beekhuizen, Johan|info:eu-repo/dai/nl/34472641X; Vermeulen, Roel|info:eu-repo/dai/nl/216532620; Martens, Luc; Röösli, Martin

Background: Concerns of the general public about potential adverse health effects caused by radio-frequency electromagnetic fields (RF-EMFs) led authorities to introduce precautionary exposure limits, which vary considerably between regions. It may be speculated that precautionary limits affect the

Electromagnetic fields from mobile phone base station - variability analysis.

Science.gov (United States)

Bienkowski, Pawel; Zubrzak, Bartlomiej

2015-09-01

The article describes the character of electromagnetic field (EMF) in mobile phone base station (BS) surroundings and its variability in time with an emphasis on the measurement difficulties related to its pulse and multi-frequency nature. Work also presents long-term monitoring measurements performed recently in different locations in Poland - small city with dispersed building development and in major polish city - dense urban area. Authors tried to determine the trends in changing of EMF spectrum analyzing daily changes of measured EMF levels in those locations. Research was performed using selective electromagnetic meters and also EMF meter with spectrum analysis.

Sensorless Control of Late-Stage Offshore DFIG-WT with FSTP Converters by Using EKF to Ride through Hybrid Faults

Directory of Open Access Journals (Sweden)

Wei Li

2017-11-01

Full Text Available A hybrid fault scenario in a late-stage offshore doubly-fed induction generator (DFIG-based wind turbine (DFIG-WT with converter open-circuit fault and position sensor failure is investigated in this paper. An extended Kalman filter (EKF-based sensorless control strategy is utilized to eliminate the encoder. Based on the detailed analysis of the seventh-order dynamic state space model of DFIG, along with the input voltage signals and measured current signals, the EKF algorithm for DFIG is designed to estimate the rotor speed and position. In addition, the bridge arm open circuit in the back-to-back (BTB power converter of DFIG is taken as a commonly-encountered fault due to the fragility of semiconductor switches. Four-switch three-phase (FSTP topology-based fault-tolerant converters are employed for post-fault operation by considering the minimization of switching losses and reducing the circuit complexity. Moreover, a simplified space vector pulse width modulation (SVPWM technique is proposed to reduce the computational burden, and a voltage balancing scheme is put forward to increase the DC-bus voltage utilization rate. Simulation studies are carried out in MATLAB/Simulink2017a (MathWorks, Natick, MA, USA to demonstrate the validity of the proposed hybrid fault-tolerant strategy for DFIG-WT, with the wind speed fluctuation, measurement noises and grid voltage sag taken into consideration.

Are people living next to mobile phone base stations more strained? Relationship of health concerns, self-estimated distance to base station, and psychological parameters.

Science.gov (United States)

Augner, Christoph; Hacker, Gerhard W

2009-12-01

Coeval with the expansion of mobile phone technology and the associated obvious presence of mobile phone base stations, some people living close to these masts reported symptoms they attributed to electromagnetic fields (EMF). Public and scientific discussions arose with regard to whether these symptoms were due to EMF or were nocebo effects. The aim of this study was to find out if people who believe that they live close to base stations show psychological or psychobiological differences that would indicate more strain or stress. Furthermore, we wanted to detect the relevant connections linking self-estimated distance between home and the next mobile phone base station (DBS), daily use of mobile phone (MPU), EMF-health concerns, electromagnetic hypersensitivity, and psychological strain parameters. Fifty-seven participants completed standardized and non-standardized questionnaires that focused on the relevant parameters. In addition, saliva samples were used as an indication to determine the psychobiological strain by concentration of alpha-amylase, cortisol, immunoglobulin A (IgA), and substance P. Self-declared base station neighbors (DBS base station neighbors are more strained than others. EMF-related health concerns cannot explain these findings. Further research should identify if actual EMF exposure or other factors are responsible for these results.

ROBUST MOTION SEGMENTATION FOR HIGH DEFINITION VIDEO SEQUENCES USING A FAST MULTI-RESOLUTION MOTION ESTIMATION BASED ON SPATIO-TEMPORAL TUBES

OpenAIRE

Brouard , Olivier; Delannay , Fabrice; Ricordel , Vincent; Barba , Dominique

2007-01-01

4 pages; International audience; Motion segmentation methods are effective for tracking video objects. However, objects segmentation methods based on motion need to know the global motion of the video in order to back-compensate it before computing the segmentation. In this paper, we propose a method which estimates the global motion of a High Definition (HD) video shot and then segments it using the remaining motion information. First, we develop a fast method for multi-resolution motion est...

Ge/Si(001) heterostructures with dense arrays of Ge quantum dots: morphology, defects, photo-emf spectra and terahertz conductivity.

Science.gov (United States)

Yuryev, Vladimir A; Arapkina, Larisa V; Storozhevykh, Mikhail S; Chapnin, Valery A; Chizh, Kirill V; Uvarov, Oleg V; Kalinushkin, Victor P; Zhukova, Elena S; Prokhorov, Anatoly S; Spektor, Igor E; Gorshunov, Boris P

2012-07-23

: Issues of Ge hut cluster array formation and growth at low temperatures on the Ge/Si(001) wetting layer are discussed on the basis of explorations performed by high resolution STM and in-situ RHEED. Dynamics of the RHEED patterns in the process of Ge hut array formation is investigated at low and high temperatures of Ge deposition. Different dynamics of RHEED patterns during the deposition of Ge atoms in different growth modes is observed, which reflects the difference in adatom mobility and their 'condensation' fluxes from Ge 2D gas on the surface for different modes, which in turn control the nucleation rates and densities of Ge clusters. Data of HRTEM studies of multilayer Ge/Si heterostructures are presented with the focus on low-temperature formation of perfect films.Heteroepitaxial Si p-i-n-diodes with multilayer stacks of Ge/Si(001) quantum dot dense arrays built in intrinsic domains have been investigated and found to exhibit the photo-emf in a wide spectral range from 0.8 to 5 μm. An effect of wide-band irradiation by infrared light on the photo-emf spectra has been observed. Photo-emf in different spectral ranges has been found to be differently affected by the wide-band irradiation. A significant increase in photo-emf is observed in the fundamental absorption range under the wide-band irradiation. The observed phenomena are explained in terms of positive and neutral charge states of the quantum dot layers and the Coulomb potential of the quantum dot ensemble. A new design of quantum dot infrared photodetectors is proposed.By using a coherent source spectrometer, first measurements of terahertz dynamical conductivity (absorptivity) spectra of Ge/Si(001) heterostructures were performed at frequencies ranged from 0.3 to 1.2 THz in the temperature interval from 300 to 5 K. The effective dynamical conductivity of the heterostructures with Ge quantum dots has been discovered to be significantly higher than that of the structure with the same amount of bulk

Trained neurons-based motion detection in optical camera communications

Science.gov (United States)

Teli, Shivani; Cahyadi, Willy Anugrah; Chung, Yeon Ho

2018-04-01

A concept of trained neurons-based motion detection (TNMD) in optical camera communications (OCC) is proposed. The proposed TNMD is based on neurons present in a neural network that perform repetitive analysis in order to provide efficient and reliable motion detection in OCC. This efficient motion detection can be considered another functionality of OCC in addition to two traditional functionalities of illumination and communication. To verify the proposed TNMD, the experiments were conducted in an indoor static downlink OCC, where a mobile phone front camera is employed as the receiver and an 8 × 8 red, green, and blue (RGB) light-emitting diode array as the transmitter. The motion is detected by observing the user's finger movement in the form of centroid through the OCC link via a camera. Unlike conventional trained neurons approaches, the proposed TNMD is trained not with motion itself but with centroid data samples, thus providing more accurate detection and far less complex detection algorithm. The experiment results demonstrate that the TNMD can detect all considered motions accurately with acceptable bit error rate (BER) performances at a transmission distance of up to 175 cm. In addition, while the TNMD is performed, a maximum data rate of 3.759 kbps over the OCC link is obtained. The OCC with the proposed TNMD combined can be considered an efficient indoor OCC system that provides illumination, communication, and motion detection in a convenient smart home environment.

An innovative, sensorless, pulsatile, continuous-flow total artificial heart: device design and initial in vitro study.

Science.gov (United States)

Fukamachi, Kiyotaka; Horvath, David J; Massiello, Alex L; Fumoto, Hideyuki; Horai, Tetsuya; Rao, Santosh; Golding, Leonard A R

2010-01-01

We are developing a very small, innovative, continuous-flow total artificial heart (CFTAH) that passively self-balances left and right pump flows and atrial pressures without sensors. This report details the CFTAH design concept and our initial in vitro data. System performance of the CFTAH was evaluated using a mock circulatory loop to determine the range of systemic and pulmonary vascular resistance (SVR and PVR) levels over which the design goal of a maximum absolute atrial pressure difference of 10 mm Hg is achieved for a steady-state flow condition. Pump speed was then modulated at 2,600 +/- 900 rpm to induce flow and arterial pressure pulsation to evaluate the effects of speed pulsations on the system performance. An automatic control mode was also evaluated. Using only passive self-regulation, pump flows were balanced and absolute atrial pressure differences were maintained at mode adjusted pump speed to achieve targeted pump flows based on sensorless calculations of SVR and CFTAH flow. The initial in vitro testing of the CFTAH with a single, valveless, continuous-flow pump demonstrated its passive self-regulation of flows and atrial pressures and a new automatic control mode. Copyright (c) 2010 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Determination of transference numbers in ionic conductors by the EMF method with active load

International Nuclear Information System (INIS)

Gorelov, V.P.

1988-01-01

Method for determining transference numbers in ionic conductors by means of measuring EMF of concentration cell with accout of polarization resistance of electrodes is suggested. The method enables to determine easily very small transference numbers of electron component against the background of predominating ionic conductivity. To illustrate the method there were determined transference numbers for the sample of industrial solid electrolyte in the cell; O 2 Pt|0.91ZrO 2 +0.09Y 2 O 3 |Pt, air

Simulink-aided Design and Implementation of Sensorless BLDC Motor Digital Control System

Science.gov (United States)

Zhilenkov, A. A.; Tsvetkov, Y. N.; Chistov, V. B.; Nyrkov, A. P.; Sokolov, S. S.

2017-07-01

The paper describes the process of creating of brushless direct current motor’s digital control system. The target motor has no speed sensor, so back-EMF method is used for commutation control. Authors show how to model the control system in MatLab/Simulink and to test it onboard STM32F4 microcontroller.This technology allows to create the most flexible system, which will control possible with a personal computer by communication lines. It is possible to examine the signals in the circuit of the actuator without any external measuring instruments - testers, oscilloscopes, etc. - and output waveforms and measured values of signals directly on the host PC.

Analysis of field-oriented controlled induction motor drives under sensor faults and an overview of sensorless schemes.

Science.gov (United States)

Arun Dominic, D; Chelliah, Thanga Raj

2014-09-01

To obtain high dynamic performance on induction motor drives (IMD), variable voltage and variable frequency operation has to be performed by measuring speed of rotation and stator currents through sensors and fed back them to the controllers. When the sensors are undergone a fault, the stability of control system, may be designed for an industrial process, is disturbed. This paper studies the negative effects on a 12.5 hp induction motor drives when the field oriented control system is subjected to sensor faults. To illustrate the importance of this study mine hoist load diagram is considered as shaft load of the tested machine. The methods to recover the system from sensor faults are discussed. In addition, the various speed sensorless schemes are reviewed comprehensively. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Effects of short-term W-CDMA mobile phone base station exposure on women with or without mobile phone related symptoms.

Science.gov (United States)

Furubayashi, Toshiaki; Ushiyama, Akira; Terao, Yasuo; Mizuno, Yoko; Shirasawa, Kei; Pongpaibool, Pornanong; Simba, Ally Y; Wake, Kanako; Nishikawa, Masami; Miyawaki, Kaori; Yasuda, Asako; Uchiyama, Mitsunori; Yamashita, Hitomi Kobayashi; Masuda, Hiroshi; Hirota, Shogo; Takahashi, Miyuki; Okano, Tomoko; Inomata-Terada, Satomi; Sokejima, Shigeru; Maruyama, Eiji; Watanabe, Soichi; Taki, Masao; Ohkubo, Chiyoji; Ugawa, Yoshikazu

2009-02-01

To investigate possible health effects of mobile phone use, we conducted a double-blind, cross-over provocation study to confirm whether subjects with mobile phone related symptoms (MPRS) are more susceptible than control subjects to the effect of electromagnetic fields (EMF) emitted from base stations. We sent questionnaires to 5,000 women and obtained 2,472 valid responses from possible candidates; from these, we recruited 11 subjects with MPRS and 43 controls. There were four EMF exposure conditions, each of which lasted 30 min: continuous, intermittent, and sham exposure with and without noise. Subjects were exposed to EMF of 2.14 GHz, 10 V/m (W-CDMA), in a shielded room to simulate whole-body exposure to EMF from base stations, although the exposure strength we used was higher than that commonly received from base stations. We measured several psychological and cognitive parameters pre- and post-exposure, and monitored autonomic functions. Subjects were asked to report on their perception of EMF and level of discomfort during the experiment. The MPRS group did not differ from the controls in their ability to detect exposure to EMF; nevertheless they consistently experienced more discomfort, regardless of whether or not they were actually exposed to EMF, and despite the lack of significant changes in their autonomic functions. Thus, the two groups did not differ in their responses to real or sham EMF exposure according to any psychological, cognitive or autonomic assessment. In conclusion, we found no evidence of any causal link between hypersensitivity symptoms and exposure to EMF from base stations. Copyright 2008 Wiley-Liss, Inc.

Robust object tracking techniques for vision-based 3D motion analysis applications

Science.gov (United States)

Knyaz, Vladimir A.; Zheltov, Sergey Y.; Vishnyakov, Boris V.

2016-04-01

Automated and accurate spatial motion capturing of an object is necessary for a wide variety of applications including industry and science, virtual reality and movie, medicine and sports. For the most part of applications a reliability and an accuracy of the data obtained as well as convenience for a user are the main characteristics defining the quality of the motion capture system. Among the existing systems for 3D data acquisition, based on different physical principles (accelerometry, magnetometry, time-of-flight, vision-based), optical motion capture systems have a set of advantages such as high speed of acquisition, potential for high accuracy and automation based on advanced image processing algorithms. For vision-based motion capture accurate and robust object features detecting and tracking through the video sequence are the key elements along with a level of automation of capturing process. So for providing high accuracy of obtained spatial data the developed vision-based motion capture system "Mosca" is based on photogrammetric principles of 3D measurements and supports high speed image acquisition in synchronized mode. It includes from 2 to 4 technical vision cameras for capturing video sequences of object motion. The original camera calibration and external orientation procedures provide the basis for high accuracy of 3D measurements. A set of algorithms as for detecting, identifying and tracking of similar targets, so for marker-less object motion capture is developed and tested. The results of algorithms' evaluation show high robustness and high reliability for various motion analysis tasks in technical and biomechanics applications.

A motion sensing-based framework for robotic manipulation.

Science.gov (United States)

Deng, Hao; Xia, Zeyang; Weng, Shaokui; Gan, Yangzhou; Fang, Peng; Xiong, Jing

2016-01-01

To data, outside of the controlled environments, robots normally perform manipulation tasks operating with human. This pattern requires the robot operators with high technical skills training for varied teach-pendant operating system. Motion sensing technology, which enables human-machine interaction in a novel and natural interface using gestures, has crucially inspired us to adopt this user-friendly and straightforward operation mode on robotic manipulation. Thus, in this paper, we presented a motion sensing-based framework for robotic manipulation, which recognizes gesture commands captured from motion sensing input device and drives the action of robots. For compatibility, a general hardware interface layer was also developed in the framework. Simulation and physical experiments have been conducted for preliminary validation. The results have shown that the proposed framework is an effective approach for general robotic manipulation with motion sensing control.

General rigid motion correction for computed tomography imaging based on locally linear embedding

Science.gov (United States)

Chen, Mianyi; He, Peng; Feng, Peng; Liu, Baodong; Yang, Qingsong; Wei, Biao; Wang, Ge

2018-02-01

The patient motion can damage the quality of computed tomography images, which are typically acquired in cone-beam geometry. The rigid patient motion is characterized by six geometric parameters and are more challenging to correct than in fan-beam geometry. We extend our previous rigid patient motion correction method based on the principle of locally linear embedding (LLE) from fan-beam to cone-beam geometry and accelerate the computational procedure with the graphics processing unit (GPU)-based all scale tomographic reconstruction Antwerp toolbox. The major merit of our method is that we need neither fiducial markers nor motion-tracking devices. The numerical and experimental studies show that the LLE-based patient motion correction is capable of calibrating the six parameters of the patient motion simultaneously, reducing patient motion artifacts significantly.

Scattered Data Processing Approach Based on Optical Facial Motion Capture

Directory of Open Access Journals (Sweden)

Qiang Zhang

2013-01-01

Full Text Available In recent years, animation reconstruction of facial expressions has become a popular research field in computer science and motion capture-based facial expression reconstruction is now emerging in this field. Based on the facial motion data obtained using a passive optical motion capture system, we propose a scattered data processing approach, which aims to solve the common problems of missing data and noise. To recover missing data, given the nonlinear relationships among neighbors with the current missing marker, we propose an improved version of a previous method, where we use the motion of three muscles rather than one to recover the missing data. To reduce the noise, we initially apply preprocessing to eliminate impulsive noise, before our proposed three-order quasi-uniform B-spline-based fitting method is used to reduce the remaining noise. Our experiments showed that the principles that underlie this method are simple and straightforward, and it delivered acceptable precision during reconstruction.

Gating treatment delivery QA based on a surrogate motion analysis

International Nuclear Information System (INIS)

Chojnowski, J.; Simpson, E.

2011-01-01

Full text: To develop a methodology to estimate intrafractional target position error during a phase-based gated treatment. Westmead Cancer Care Centre is using respiratory correlated phase-based gated beam delivery in the treatment of lung cancer. The gating technique is managed by the Varian Real-time Position Management (RPM) system, version 1.7.5. A 6-dot block is placed on the abdomen of the patient and acts as a surrogate for the target motion. During a treatment session, the motion of the surrogate can be recorded by RPM application. Analysis of the surrogate motion file by in-house developed software allows the intrafractional error of the treatment session to be computed. To validate the computed error, a simple test that involves the introduction of deliberate errors is performed. Errors of up to 1.1 cm are introduced to a metal marker placed on a surrogate using the Varian Breathing Phantom. The moving marker was scanned in prospective mode using a GE Lightspeed 16 CT scanner. Using the CT images, a difference of the marker position with and without introduced errors is compared to the calculated errors based on the surrogate motion. The average and standard deviation of a difference between calculated target position errors and measured introduced artificial errors of the marker position is 0.02 cm and 0.07 cm respectively. Conclusion The calculated target positional error based on surrogate motion analysis provides a quantitative measure of intrafractional target positional errors during treatment. Routine QA for gated treatment using surrogate motion analysis is relatively quick and simple.

Facial motion parameter estimation and error criteria in model-based image coding

Science.gov (United States)

Liu, Yunhai; Yu, Lu; Yao, Qingdong

2000-04-01

Model-based image coding has been given extensive attention due to its high subject image quality and low bit-rates. But the estimation of object motion parameter is still a difficult problem, and there is not a proper error criteria for the quality assessment that are consistent with visual properties. This paper presents an algorithm of the facial motion parameter estimation based on feature point correspondence and gives the motion parameter error criteria. The facial motion model comprises of three parts. The first part is the global 3-D rigid motion of the head, the second part is non-rigid translation motion in jaw area, and the third part consists of local non-rigid expression motion in eyes and mouth areas. The feature points are automatically selected by a function of edges, brightness and end-node outside the blocks of eyes and mouth. The numbers of feature point are adjusted adaptively. The jaw translation motion is tracked by the changes of the feature point position of jaw. The areas of non-rigid expression motion can be rebuilt by using block-pasting method. The estimation approach of motion parameter error based on the quality of reconstructed image is suggested, and area error function and the error function of contour transition-turn rate are used to be quality criteria. The criteria reflect the image geometric distortion caused by the error of estimated motion parameters properly.

PET Motion Compensation for Radiation Therapy Using a CT-Based Mid-Position Motion Model: Methodology and Clinical Evaluation

International Nuclear Information System (INIS)

Kruis, Matthijs F.; Kamer, Jeroen B. van de; Houweling, Antonetta C.; Sonke, Jan-Jakob; Belderbos, José S.A.; Herk, Marcel van

2013-01-01

Purpose: Four-dimensional positron emission tomography (4D PET) imaging of the thorax produces sharper images with reduced motion artifacts. Current radiation therapy planning systems, however, do not facilitate 4D plan optimization. When images are acquired in a 2-minute time slot, the signal-to-noise ratio of each 4D frame is low, compromising image quality. The purpose of this study was to implement and evaluate the construction of mid-position 3D PET scans, with motion compensated using a 4D computed tomography (CT)-derived motion model. Methods and Materials: All voxels of 4D PET were registered to the time-averaged position by using a motion model derived from the 4D CT frames. After the registration the scans were summed, resulting in a motion-compensated 3D mid-position PET scan. The method was tested with a phantom dataset as well as data from 27 lung cancer patients. Results: PET motion compensation using a CT-based motion model improved image quality of both phantoms and patients in terms of increased maximum SUV (SUV max ) values and decreased apparent volumes. In homogenous phantom data, a strong relationship was found between the amplitude-to-diameter ratio and the effects of the method. In heterogeneous patient data, the effect correlated better with the motion amplitude. In case of large amplitudes, motion compensation may increase SUV max up to 25% and reduce the diameter of the 50% SUV max volume by 10%. Conclusions: 4D CT-based motion-compensated mid-position PET scans provide improved quantitative data in terms of uptake values and volumes at the time-averaged position, thereby facilitating more accurate radiation therapy treatment planning of pulmonary lesions

Group-based Motion Detection for Energy-Efficient Localisation

Directory of Open Access Journals (Sweden)

Alban Cotillon

2012-10-01

Full Text Available Long-term outdoor localization remains challenging due to the high energy profiles of GPS modules. Duty cycling the GPS module combined with inertial sensors can improve energy consumption. However, inertial sensors that are kept active all the time can also drain mobile node batteries. This paper proposes duty cycling strategies for inertial sensors to maintain a target position accuracy and node lifetime. We present a method for duty cycling motion sensors according to features of movement events, and evaluate its energy and accuracy profile for an empirical data trace of cattle movement. We further introduce the concept of group-based duty cycling, where nodes that cluster together can share the burden of motion detection to reduce their duty cycles. Our evaluation shows that both variants of motion sensor duty cycling yield up to 78% improvement in overall node power consumption, and that the group-based method yields an additional 20% power reduction during periods of low mobility.

Engineering uses of physics-based ground motion simulations

Science.gov (United States)

Baker, Jack W.; Luco, Nicolas; Abrahamson, Norman A.; Graves, Robert W.; Maechling, Phillip J.; Olsen, Kim B.

2014-01-01

This paper summarizes validation methodologies focused on enabling ground motion simulations to be used with confidence in engineering applications such as seismic hazard analysis and dynmaic analysis of structural and geotechnical systems. Numberical simullation of ground motion from large erthquakes, utilizing physics-based models of earthquake rupture and wave propagation, is an area of active research in the earth science community. Refinement and validatoin of these models require collaboration between earthquake scientists and engineering users, and testing/rating methodolgies for simulated ground motions to be used with confidence in engineering applications. This paper provides an introduction to this field and an overview of current research activities being coordinated by the Souther California Earthquake Center (SCEC). These activities are related both to advancing the science and computational infrastructure needed to produce ground motion simulations, as well as to engineering validation procedures. Current research areas and anticipated future achievements are also discussed.

EMF-research 1993-2003[Health hazards from Electromagnetic fields]; EMF-forskning 1993-2003

Energy Technology Data Exchange (ETDEWEB)

Lundberg, Petra; Lindgren, Rolf [SwedPower AB, Stockholm (Sweden)

2005-09-01

This report summarises 10 years of research on power frequency electric and magnetic fields. Cancer is the topic for which most research has been carried out during the 10-year-period. Epidemiological studies have shown statistical correlations between long time exposure to magnetic fields and a few forms of cancer. The most obvious correlation is between childhood leukaemia and magnetic fields from power lines. However, the correlations correspond to very small increases in risk and since there is no experimental evidence and no trustworthy mechanism exists, a cause-and-effect relationship cannot be established. Furthermore, there are also comprehensive and well-performed studies which show no correlations. Some studies indicate a correlation between electric and magnetic fields and cognitive functions and diffuse central nervous symptoms. The results show correspondence with the hypothesis that magnetic fields cause a chronic stress effect to the central nervous system. A relatively strong correlation has been shown between ALS (amyotrophic lateral sclerosis) and electricity related labour. EMF is however only one of several conceivable explanations. An equivalent, although weaker, correlation has also been shown for Alzheimer's decease. It can be stated that frequent electric and magnetic fields do not seem to have any influence on reproducibility, such as damage on the foetus or negative effects on the reproduction in humans or animals. A potentially important area is the effect on the immune system in humans and animals. In fact, it has been noted that magnetic fields may activate the immune system whilst long term exposure seems to impoverish the capacity of the immune system. The research on field variables and connected mechanisms shows that intermittent magnetic fields have stronger biological impact than continuous fields. Another observation is that biological effects often appear as window effects in amplitude, frequency and sometimes even in time

EMF radiations (1800 MHz)-inhibited early seedling growth of maize (Zea mays) involves alterations in starch and sucrose metabolism.

Science.gov (United States)

Kumar, Arvind; Singh, Harminder Pal; Batish, Daizy R; Kaur, Shalinder; Kohli, Ravinder Kumar

2016-07-01

The present study investigated the impact of 1800-MHz electromagnetic field radiations (EMF-r), widely used in mobile communication, on the growth and activity of starch-, sucrose-, and phosphate-hydrolyzing enzymes in Zea mays seedlings. We exposed Z. mays to modulated continuous wave homogenous EMF-r at specific absorption rate (SAR) of 1.69±0.0 × 10(-1) W kg(-1) for ½, 1, 2, and 4 h. The analysis of seedlings after 7 days revealed that short-term exposure did not induce any significant change, while longer exposure of 4 h caused significant growth and biochemical alterations. There was a reduction in the root and coleoptile length with more pronounced effect on coleoptile growth (23 % reduction on 4-h exposure). The contents of photosynthetic pigments and total carbohydrates declined by 13 and 18 %, respectively, in 4-h exposure treatments compared to unexposed control. The activity of starch-hydrolyzing enzymes-α- and β-amylases-increased by ∼92 and 94 %, respectively, at an exposure duration of 4 h, over that in the control. In response to 4-h exposure treatment, the activity of sucrolytic enzymes-acid invertases and alkaline invertases-was increased by 88 and 266 %, whereas the specific activities of phosphohydrolytic enzymes (acid phosphatases and alkaline phosphatases) showed initial increase up to ≤2 h duration and then declined at >2 h exposure duration. The study concludes that EMF-r-inhibited seedling growth of Z. mays involves interference with starch and sucrose metabolism.

Robotics-based synthesis of human motion

KAUST Repository

Khatib, O.; Demircan, E.; De Sapio, V.; Sentis, L.; Besier, T.; Delp, S.

2009-01-01

The synthesis of human motion is a complex procedure that involves accurate reconstruction of movement sequences, modeling of musculoskeletal kinematics, dynamics and actuation, and characterization of reliable performance criteria. Many of these processes have much in common with the problems found in robotics research. Task-based methods used in robotics may be leveraged to provide novel musculoskeletal modeling methods and physiologically accurate performance predictions. In this paper, we present (i) a new method for the real-time reconstruction of human motion trajectories using direct marker tracking, (ii) a task-driven muscular effort minimization criterion and (iii) new human performance metrics for dynamic characterization of athletic skills. Dynamic motion reconstruction is achieved through the control of a simulated human model to follow the captured marker trajectories in real-time. The operational space control and real-time simulation provide human dynamics at any configuration of the performance. A new criteria of muscular effort minimization has been introduced to analyze human static postures. Extensive motion capture experiments were conducted to validate the new minimization criterion. Finally, new human performance metrics were introduced to study in details an athletic skill. These metrics include the effort expenditure and the feasible set of operational space accelerations during the performance of the skill. The dynamic characterization takes into account skeletal kinematics as well as muscle routing kinematics and force generating capacities. The developments draw upon an advanced musculoskeletal modeling platform and a task-oriented framework for the effective integration of biomechanics and robotics methods.

Robotics-based synthesis of human motion

KAUST Repository

Khatib, O.

2009-05-01

The synthesis of human motion is a complex procedure that involves accurate reconstruction of movement sequences, modeling of musculoskeletal kinematics, dynamics and actuation, and characterization of reliable performance criteria. Many of these processes have much in common with the problems found in robotics research. Task-based methods used in robotics may be leveraged to provide novel musculoskeletal modeling methods and physiologically accurate performance predictions. In this paper, we present (i) a new method for the real-time reconstruction of human motion trajectories using direct marker tracking, (ii) a task-driven muscular effort minimization criterion and (iii) new human performance metrics for dynamic characterization of athletic skills. Dynamic motion reconstruction is achieved through the control of a simulated human model to follow the captured marker trajectories in real-time. The operational space control and real-time simulation provide human dynamics at any configuration of the performance. A new criteria of muscular effort minimization has been introduced to analyze human static postures. Extensive motion capture experiments were conducted to validate the new minimization criterion. Finally, new human performance metrics were introduced to study in details an athletic skill. These metrics include the effort expenditure and the feasible set of operational space accelerations during the performance of the skill. The dynamic characterization takes into account skeletal kinematics as well as muscle routing kinematics and force generating capacities. The developments draw upon an advanced musculoskeletal modeling platform and a task-oriented framework for the effective integration of biomechanics and robotics methods.

MRI-Based Nonrigid Motion Correction in Simultaneous PET/MRI

Science.gov (United States)

Chun, Se Young; Reese, Timothy G.; Ouyang, Jinsong; Guerin, Bastien; Catana, Ciprian; Zhu, Xuping; Alpert, Nathaniel M.; El Fakhri, Georges

2014-01-01

Respiratory and cardiac motion is the most serious limitation to whole-body PET, resulting in spatial resolution close to 1 cm. Furthermore, motion-induced inconsistencies in the attenuation measurements often lead to significant artifacts in the reconstructed images. Gating can remove motion artifacts at the cost of increased noise. This paper presents an approach to respiratory motion correction using simultaneous PET/MRI to demonstrate initial results in phantoms, rabbits, and nonhuman primates and discusses the prospects for clinical application. Methods Studies with a deformable phantom, a free-breathing primate, and rabbits implanted with radioactive beads were performed with simultaneous PET/MRI. Motion fields were estimated from concurrently acquired tagged MR images using 2 B-spline nonrigid image registration methods and incorporated into a PET list-mode ordered-subsets expectation maximization algorithm. Using the measured motion fields to transform both the emission data and the attenuation data, we could use all the coincidence data to reconstruct any phase of the respiratory cycle. We compared the resulting SNR and the channelized Hotelling observer (CHO) detection signal-to-noise ratio (SNR) in the motion-corrected reconstruction with the results obtained from standard gating and uncorrected studies. Results Motion correction virtually eliminated motion blur without reducing SNR, yielding images with SNR comparable to those obtained by gating with 5–8 times longer acquisitions in all studies. The CHO study in dynamic phantoms demonstrated a significant improvement (166%–276%) in lesion detection SNR with MRI-based motion correction as compared with gating (P < 0.001). This improvement was 43%–92% for large motion compared with lesion detection without motion correction (P < 0.001). CHO SNR in the rabbit studies confirmed these results. Conclusion Tagged MRI motion correction in simultaneous PET/MRI significantly improves lesion detection

Fast Fourier and discrete wavelet transforms applied to sensorless vector control induction motor for rotor bar faults diagnosis.

Science.gov (United States)

Talhaoui, Hicham; Menacer, Arezki; Kessal, Abdelhalim; Kechida, Ridha

2014-09-01

This paper presents new techniques to evaluate faults in case of broken rotor bars of induction motors. Procedures are applied with closed-loop control. Electrical and mechanical variables are treated using fast Fourier transform (FFT), and discrete wavelet transform (DWT) at start-up and steady state. The wavelet transform has proven to be an excellent mathematical tool for the detection of the faults particularly broken rotor bars type. As a performance, DWT can provide a local representation of the non-stationary current signals for the healthy machine and with fault. For sensorless control, a Luenberger observer is applied; the estimation rotor speed is analyzed; the effect of the faults in the speed pulsation is compensated; a quadratic current appears and used for fault detection. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Real-time high-speed motion blur compensation system based on back-and-forth motion control of galvanometer mirror.

Science.gov (United States)

Hayakawa, Tomohiko; Watanabe, Takanoshin; Ishikawa, Masatoshi

2015-12-14

We developed a novel real-time motion blur compensation system for the blur caused by high-speed one-dimensional motion between a camera and a target. The system consists of a galvanometer mirror and a high-speed color camera, without the need for any additional sensors. We controlled the galvanometer mirror with continuous back-and-forth oscillating motion synchronized to a high-speed camera. The angular speed of the mirror is given in real time within 10 ms based on the concept of background tracking and rapid raw Bayer block matching. Experiments demonstrated that our system captures motion-invariant images of objects moving at speeds up to 30 km/h.

Ship motion-based wave estimation using a spectral residual-calculation

DEFF Research Database (Denmark)

Nielsen, Ulrik D.; H. Brodtkorb, Astrid

2018-01-01

This paper presents a study focused on a newly developed procedure for wave spectrum estimation using wave-induced motion recordings from a ship. The particular procedure stands out from other existing, similar ship motion-based pro-cedures by its computational efficiency and - at the same time- ...

Using Load Balancing to Scalably Parallelize Sampling-Based Motion Planning Algorithms

KAUST Repository

Fidel, Adam; Jacobs, Sam Ade; Sharma, Shishir; Amato, Nancy M.; Rauchwerger, Lawrence

2014-01-01

Motion planning, which is the problem of computing feasible paths in an environment for a movable object, has applications in many domains ranging from robotics, to intelligent CAD, to protein folding. The best methods for solving this PSPACE-hard problem are so-called sampling-based planners. Recent work introduced uniform spatial subdivision techniques for parallelizing sampling-based motion planning algorithms that scaled well. However, such methods are prone to load imbalance, as planning time depends on region characteristics and, for most problems, the heterogeneity of the sub problems increases as the number of processors increases. In this work, we introduce two techniques to address load imbalance in the parallelization of sampling-based motion planning algorithms: an adaptive work stealing approach and bulk-synchronous redistribution. We show that applying these techniques to representatives of the two major classes of parallel sampling-based motion planning algorithms, probabilistic roadmaps and rapidly-exploring random trees, results in a more scalable and load-balanced computation on more than 3,000 cores. © 2014 IEEE.

Using Load Balancing to Scalably Parallelize Sampling-Based Motion Planning Algorithms

KAUST Repository

Fidel, Adam

2014-05-01

Motion planning, which is the problem of computing feasible paths in an environment for a movable object, has applications in many domains ranging from robotics, to intelligent CAD, to protein folding. The best methods for solving this PSPACE-hard problem are so-called sampling-based planners. Recent work introduced uniform spatial subdivision techniques for parallelizing sampling-based motion planning algorithms that scaled well. However, such methods are prone to load imbalance, as planning time depends on region characteristics and, for most problems, the heterogeneity of the sub problems increases as the number of processors increases. In this work, we introduce two techniques to address load imbalance in the parallelization of sampling-based motion planning algorithms: an adaptive work stealing approach and bulk-synchronous redistribution. We show that applying these techniques to representatives of the two major classes of parallel sampling-based motion planning algorithms, probabilistic roadmaps and rapidly-exploring random trees, results in a more scalable and load-balanced computation on more than 3,000 cores. © 2014 IEEE.

PROMO – Real-time Prospective Motion Correction in MRI using Image-based Tracking

Science.gov (United States)

White, Nathan; Roddey, Cooper; Shankaranarayanan, Ajit; Han, Eric; Rettmann, Dan; Santos, Juan; Kuperman, Josh; Dale, Anders

2010-01-01

Artifacts caused by patient motion during scanning remain a serious problem in most MRI applications. The prospective motion correction technique attempts to address this problem at its source by keeping the measurement coordinate system fixed with respect to the patient throughout the entire scan process. In this study, a new image-based approach for prospective motion correction is described, which utilizes three orthogonal 2D spiral navigator acquisitions (SP-Navs) along with a flexible image-based tracking method based on the Extended Kalman Filter (EKF) algorithm for online motion measurement. The SP-Nav/EKF framework offers the advantages of image-domain tracking within patient-specific regions-of-interest and reduced sensitivity to off-resonance-induced corruption of rigid-body motion estimates. The performance of the method was tested using offline computer simulations and online in vivo head motion experiments. In vivo validation results covering a broad range of staged head motions indicate a steady-state error of the SP-Nav/EKF motion estimates of less than 10 % of the motion magnitude, even for large compound motions that included rotations over 15 degrees. A preliminary in vivo application in 3D inversion recovery spoiled gradient echo (IR-SPGR) and 3D fast spin echo (FSE) sequences demonstrates the effectiveness of the SP-Nav/EKF framework for correcting 3D rigid-body head motion artifacts prospectively in high-resolution 3D MRI scans. PMID:20027635

Vision-based human motion analysis: An overview

NARCIS (Netherlands)

Poppe, Ronald Walter

2007-01-01

Markerless vision-based human motion analysis has the potential to provide an inexpensive, non-obtrusive solution for the estimation of body poses. The significant research effort in this domain has been motivated by the fact that many application areas, including surveillance, Human-Computer

Assessment of electromagnetic fields intensity emitted by cellular phone base stations in surrounding flats - a preliminary study

International Nuclear Information System (INIS)

Zmyslony, M.; Politanski, P.; Mamrot, P.; Bortkiewicz, A.

2006-01-01

A rapid development of mobile telecommunications (MT) has resulted in an increased concern about possible detrimental health effects of electromagnetic fields (EMFs) emitted by MT systems, and by MT base stations in particular. Research into EMFs effects on the health of inhabitants living in their vicinity requires first of all a solid assessment of the exposure level. Up to now, the reports in this field have been rather scant. This article presents the results of preliminary measurements of EMFs fields in selected flats around selected base stations in the city of Lodz. Measurements of electric field strength, E, to assess EMF exposure were based on the standard procedures currently in force in Poland. As the study is regarded as a preliminary one, the measurements were conducted in buildings with the expected largest radiation. The measurements show that in the flats located up to 500 m from the base station, EMFs are within the limits specified by relevant Polish regulations on the general public and environmental protection. It was also observed that in a few (less than 10%) flats the field with E exceeded 0.8 V/m. The results show that there are no correlations between electric field strength and distance between the flat and the base station. Therefore, the distance from the base station cannot be used to represent the exposure rate; to determine the latter, EMF measurements are necessary. (author)

A scheme for PET data normalization in event-based motion correction

International Nuclear Information System (INIS)

Zhou, Victor W; Kyme, Andre Z; Fulton, Roger; Meikle, Steven R

2009-01-01

Line of response (LOR) rebinning is an event-based motion-correction technique for positron emission tomography (PET) imaging that has been shown to compensate effectively for rigid motion. It involves the spatial transformation of LORs to compensate for motion during the scan, as measured by a motion tracking system. Each motion-corrected event is then recorded in the sinogram bin corresponding to the transformed LOR. It has been shown previously that the corrected event must be normalized using a normalization factor derived from the original LOR, that is, based on the pair of detectors involved in the original coincidence event. In general, due to data compression strategies (mashing), sinogram bins record events detected on multiple LORs. The number of LORs associated with a sinogram bin determines the relative contribution of each LOR. This paper provides a thorough treatment of event-based normalization during motion correction of PET data using LOR rebinning. We demonstrate theoretically and experimentally that normalization of the corrected event during LOR rebinning should account for the number of LORs contributing to the sinogram bin into which the motion-corrected event is binned. Failure to account for this factor may cause artifactual slice-to-slice count variations in the transverse slices and visible horizontal stripe artifacts in the coronal and sagittal slices of the reconstructed images. The theory and implementation of normalization in conjunction with the LOR rebinning technique is described in detail, and experimental verification of the proposed normalization method in phantom studies is presented.

Health effect from EMF exposure of Korea population

Energy Technology Data Exchange (ETDEWEB)

Kim, Y. S.; Cho, Y. S.; Lee, J. T.; Yup, M. J.; Hong, J. H. [Institute of Environmental and Industrrial Medicine, Hanyang Univ., Seoul (Korea, Republic of)

2002-07-01

This study on health effect from EMF exposure was performed from June 2001 to April 2002 to compare changes in melatonin levels in urine of 40 subjects during their normal sleeping hours, to evaluate heart rate, ST segment in ventricular, and ventricular premature beat for cardiac function, to evaluate microwave exposure from cellular phones which may have a potential influence on the electro physiologic function of human brain, and each 20 subjects in occupational and non-occupational group measured personal 24-h continual exposure, using EMDEX(for 40-800Hz, Enertech Consultant, Inc.). An urine samples for analysis of melatonin excretion level were collected 1 times a day(immediately after wake-up) for five days from each subjects and analyzed by radioimmunoassay, HRV-test for relationship between heart rate and EMF exposure was performed heart rate beat using Holter for subjects, and double EEG-test were performed in 10 long-term users of the cellularphones when using and not using them, and a single EEG-test in 10 short-term users of the cellular phones. Each EEG-recording took 40 min consisting of 30 min filed exposure and 10 min measurement. And We estimated the economic value of the potential damage of electromagnetic radiation from cellular phone, and the willingness to pay of people for the study of the radiation damage led by the government, by applying contingent variation method. The results of this study were followed; 1. Personal exposure assessment 2. We showed not significant difference for the subjective average melatonin levels between occupational and non- occupational groups exposed to electromagnetic fields. 3. We showed no difference in the awake EEGs in terms of spectral power density measures between long-term users and short-term users of cellular phones. 4. We found that the economic value of the potential damage by the radiation for a typical cellular phone user is about 20,000 won per year and he would be willing to pay about 1,800 won

Direct catalytic transformation of carbohydrates into 5-ethoxymethylfurfural with acid–base bifunctional hybrid nanospheres

DEFF Research Database (Denmark)

Li, Hu; Khokarale, Santosh Govind; Kotni, Ramakrishna

2014-01-01

carbohydrates. A high EMF yield of 76.6%, 58.5%, 42.4%, and 36.5% could be achieved, when fructose, inulin, sorbose, and sucrose were used as starting materials, respectively. Although, the acid–base bifunctional nanocatalysts were inert for synthesis of EMF from glucose based carbohydrates, ethyl...

Photo-EMF Sensitivity of Porous Silicon Thin Layer–Crystalline Silicon Heterojunction to Ammonia Adsorption

Directory of Open Access Journals (Sweden)

Kae Dal Kwack

2011-01-01

Full Text Available A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light.

Photo-EMF sensitivity of porous silicon thin layer-crystalline silicon heterojunction to ammonia adsorption.

Science.gov (United States)

Vashpanov, Yuriy; Jung, Jae Il; Kwack, Kae Dal

2011-01-01

A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light.

Photo-EMF Sensitivity of Porous Silicon Thin Layer–Crystalline Silicon Heterojunction to Ammonia Adsorption

Science.gov (United States)

Vashpanov, Yuriy; Jung, Jae Il; Kwack, Kae Dal

2011-01-01

A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light. PMID:22319353

Aggregated data from two double-blind base station provocation studies comparing individuals with idiopathic environmental intolerance with attribution to electromagnetic fields and controls.

Science.gov (United States)

Eltiti, Stacy; Wallace, Denise; Russo, Riccardo; Fox, Elaine

2015-02-01

Data from two previous studies were aggregated to provide a statistically powerful test of whether exposure to electromagnetic fields (EMFs) produced by telecommunication base stations negatively affects well-being in individuals who report idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) and control participants. A total of 102 IEI-EMF and 237 controls participated in open provocation trials and 88 IEI-EMF and 231 controls went on to complete double-blind trials in which they were exposed to EMFs from a base station emitting either a Global System for Mobile Communication and Universal Mobile Telecommunications System or a Terrestrial Trunked Radio Telecommunications System signal. Both experiments included a comparison sham condition. Visual analog and symptom scales measured subjective well-being. Results showed that IEI-EMF participants reported lower levels of well-being during real compared to sham exposure during open provocation, but not during double-blind trials. Additionally, participants reported lower levels of well-being during high compared to low load trials and this did not interact with radiofrequency-EMF exposure. These findings are consistent with a growing body of literature indicating there is no causal relationship between short-term exposure to EMFs and subjective well-being in members of the public whether or not they report perceived sensitivity to EMFs. © 2015 Wiley Periodicals, Inc.

SpoonEMF, une brique logicielle pour l'utilisation de l'IDM dans le cadre de la réingénierie de programmes Java5

OpenAIRE

Barais , Olivier

2006-01-01

2 ième Journée sur l'Ingénièrie Dirigée par les Modèles; Ce document présente succinctement SpoonEMF, une brique logicielle pour l'utilisation de l'IDM dans le cadre de la réingénierie d'applications écrites en Java. L'accent dans cette courte présentation est mis sur les cas d'utilisation possibles de cette brique logicielle et l'intérêt des choix techniques retenus : le framework EMF pour l'expression du méta-modèle afin de favoriser l'interopérabilité avec d'autres outils et l'intégration ...

Hand Motion-Based Remote Control Interface with Vibrotactile Feedback for Home Robots

Directory of Open Access Journals (Sweden)

Juan Wu

2013-06-01

Full Text Available This paper presents the design and implementation of a hand-held interface system for the locomotion control of home robots. A handheld controller is proposed to implement hand motion recognition and hand motion-based robot control. The handheld controller can provide a ‘connect-and-play’ service for the users to control the home robot with visual and vibrotactile feedback. Six natural hand gestures are defined for navigating the home robots. A three-axis accelerometer is used to detect the hand motions of the user. The recorded acceleration data are analysed and classified to corresponding control commands according to their characteristic curves. A vibration motor is used to provide vibrotactile feedback to the user when an improper operation is performed. The performances of the proposed hand motion-based interface and the traditional keyboard and mouse interface have been compared in robot navigation experiments. The experimental results of home robot navigation show that the success rate of the handheld controller is 13.33% higher than the PC based controller. The precision of the handheld controller is 15.4% more than that of the PC and the execution time is 24.7% less than the PC based controller. This means that the proposed hand motion-based interface is more efficient and flexible.

Simulation of spatiotemporal CT data sets using a 4D MRI-based lung motion model.

Science.gov (United States)

Marx, Mirko; Ehrhardt, Jan; Werner, René; Schlemmer, Heinz-Peter; Handels, Heinz

2014-05-01

Four-dimensional CT imaging is widely used to account for motion-related effects during radiotherapy planning of lung cancer patients. However, 4D CT often contains motion artifacts, cannot be used to measure motion variability, and leads to higher dose exposure. In this article, we propose using 4D MRI to acquire motion information for the radiotherapy planning process. From the 4D MRI images, we derive a time-continuous model of the average patient-specific respiratory motion, which is then applied to simulate 4D CT data based on a static 3D CT. The idea of the motion model is to represent the average lung motion over a respiratory cycle by cyclic B-spline curves. The model generation consists of motion field estimation in the 4D MRI data by nonlinear registration, assigning respiratory phases to the motion fields, and applying a B-spline approximation on a voxel-by-voxel basis to describe the average voxel motion over a breathing cycle. To simulate a patient-specific 4D CT based on a static CT of the patient, a multi-modal registration strategy is introduced to transfer the motion model from MRI to the static CT coordinates. Differences between model-based estimated and measured motion vectors are on average 1.39 mm for amplitude-based binning of the 4D MRI data of three patients. In addition, the MRI-to-CT registration strategy is shown to be suitable for the model transformation. The application of our 4D MRI-based motion model for simulating 4D CT images provides advantages over standard 4D CT (less motion artifacts, radiation-free). This makes it interesting for radiotherapy planning.

Applications of Phase-Based Motion Processing

Science.gov (United States)

Branch, Nicholas A.; Stewart, Eric C.

2018-01-01

Image pyramids provide useful information in determining structural response at low cost using commercially available cameras. The current effort applies previous work on the complex steerable pyramid to analyze and identify imperceptible linear motions in video. Instead of implicitly computing motion spectra through phase analysis of the complex steerable pyramid and magnifying the associated motions, instead present a visual technique and the necessary software to display the phase changes of high frequency signals within video. The present technique quickly identifies regions of largest motion within a video with a single phase visualization and without the artifacts of motion magnification, but requires use of the computationally intensive Fourier transform. While Riesz pyramids present an alternative to the computationally intensive complex steerable pyramid for motion magnification, the Riesz formulation contains significant noise, and motion magnification still presents large amounts of data that cannot be quickly assessed by the human eye. Thus, user-friendly software is presented for quickly identifying structural response through optical flow and phase visualization in both Python and MATLAB.

Mobile technology and telemedicine for shoulder range of motion: validation of a motion-based machine-learning software development kit.

Science.gov (United States)

Ramkumar, Prem N; Haeberle, Heather S; Navarro, Sergio M; Sultan, Assem A; Mont, Michael A; Ricchetti, Eric T; Schickendantz, Mark S; Iannotti, Joseph P

2018-03-07

Mobile technology offers the prospect of delivering high-value care with increased patient access and reduced costs. Advances in mobile health (mHealth) and telemedicine have been inhibited by the lack of interconnectivity between devices and software and inability to process consumer sensor data. The objective of this study was to preliminarily validate a motion-based machine learning software development kit (SDK) for the shoulder compared with a goniometer for 4 arcs of motion: (1) abduction, (2) forward flexion, (3) internal rotation, and (4) external rotation. A mobile application for the SDK was developed and "taught" 4 arcs of shoulder motion. Ten subjects without shoulder pain or prior shoulder surgery performed the arcs of motion for 5 repetitions. Each motion was measured by the SDK and compared with a physician-measured manual goniometer measurement. Angular differences between SDK and goniometer measurements were compared with univariate and power analyses. The comparison between the SDK and goniometer measurement detected a mean difference of less than 5° for all arcs of motion (P > .05), with a 94% chance of detecting a large effect size from a priori power analysis. Mean differences for the arcs of motion were: abduction, -3.7° ± 3.2°; forward flexion, -4.9° ± 2.5°; internal rotation, -2.4° ± 3.7°; and external rotation -2.6° ± 3.4°. The SDK has the potential to remotely substitute for a shoulder range of motion examination within 5° of goniometer measurements. An open-source motion-based SDK that can learn complex movements, including clinical shoulder range of motion, from consumer sensors offers promise for the future of mHealth, particularly in telemonitoring before and after orthopedic surgery. Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Extremely Low Frequency Electromagnetic Field (ELF-EMF and childhood leukemia near transmission lines: a review

Directory of Open Access Journals (Sweden)

P. A. Kokate

2016-04-01

Full Text Available This article presents a systematic review of most cited studies from developed countries those shed light on the potential relation between childhood leukemia and extremely low frequency electromagnetic field (ELF-EMF. All the findings of articles critically segregated as per some neglected parameters like number of samples, exposure duration, frequency range, distance from the radiation sources, and location during measurement of magnetic field density near power lines. Literature of major 50 studies are divided according to pooled analysis / meta-analysis, residential zone assessment and case-control studies.

Base response arising from free-field motions

International Nuclear Information System (INIS)

Whitley, J.R.; Morgan, J.R.; Hall, W.J.; Newmark, N.M.

1977-01-01

A procedure is illustrated in this paper for deriving (estimating) from a free-field record the horizontal base motions of a building, including horizontal rotation and translation. More specifically the goal was to compare results of response calculations based on derived accelerations with the results of calculations based on recorded accelerations. The motions are determined by assuming that an actual recorded ground wave transits a rigid base of a given dimension. Calculations given in the paper were made employing the earthquake acceleration time histories of the Hollywood storage building and the adjacent P.E. lot for the Kern County (1952) and San Fernando (1971) earthquakes. For the Kern County earthquake the derived base corner accelerations, including the effect of rotation show generally fair agreement with the spectra computed from the Hollywood storage corner record. For the San Fernando earthquake the agreement between the spectra computed from derived base corner accelerations and that computed from the actual basement corner record is not as good as that for the Kern County earthquake. These limited studies admittedly are hardly a sufficient basis on which to form a judgment, but these differences noted probably can be attributed in part to foundation distortion, building feedback, distance between measurement points, and soil structure interaction; it was not possible to take any of these factors into account in these particular calculations

Ego-motion based on EM for bionic navigation

Science.gov (United States)

Yue, Xiaofeng; Wang, L. J.; Liu, J. G.

2015-12-01

Researches have proved that flying insects such as bees can achieve efficient and robust flight control, and biologists have explored some biomimetic principles regarding how they control flight. Based on those basic studies and principles acquired from the flying insects, this paper proposes a different solution of recovering ego-motion for low level navigation. Firstly, a new type of entropy flow is provided to calculate the motion parameters. Secondly, EKF, which has been used for navigation for some years to correct accumulated error, and estimation-Maximization, which is always used to estimate parameters, are put together to determine the ego-motion estimation of aerial vehicles. Numerical simulation on MATLAB has proved that this navigation system provides more accurate position and smaller mean absolute error than pure optical flow navigation. This paper has done pioneering work in bionic mechanism to space navigation.

Reliable selection of earthquake ground motions for performance-based design

DEFF Research Database (Denmark)

Katsanos, Evangelos; Sextos, A.G.

2016-01-01

A decision support process is presented to accommodate selecting and scaling of earthquake motions as required for the time domain analysis of structures. Prequalified code-compatible suites of seismic motions are provided through a multi-criterion approach to satisfy prescribed reduced variability...... of the method, by being subjected to numerous suites of motions that were highly ranked according to both the proposed approach (δsv-sc) and the conventional index (δconv), already used by most existing code-based earthquake records selection and scaling procedures. The findings reveal the superiority...

Numerous Sinusoidal and Other EMF Phenomena, At Present and Former Native American Sites, May Be Superimposing Themselves onto Regional Power Grids.

Science.gov (United States)

Cadran, Lawrence R.; Mc Leod, Roger D.; Mc Leod, David M.

2003-10-01

Periodic electromagnetic field signals (EMF), sometimes noticeable as faint blue-light or other phenomena, frequently are also detected at sites associated with Native Americans. We first noticed this sort of information in the vicinity of Wendell, MA about fourteen years ago. Similar and other signals are apparent at Americas Stonehenge, AS, in North Salem, NH. Connecticut provided our first evidence of superposition of two such waves at the Gungywamp site north of Groton, CT. A Maine location first showed orthogonally oriented trajectories in neighborhoods formerly frequented by Molocket and Metallak and their relatives near Rumford and Rangeley, ME. Florida exhibits similar signals in the vicinity of Hollywood and at Miamis Tequesta instrument, as does a separate site in CT. Powerful thunderstorms in the vicinity of a stone serpent effigy in Ohio cause EMF pulsations. Such signals are possibly superimposing themselves onto power-grids, where frequency changes and system instabilities may occur, according to the elementary physics involved.

Automatic Motion Generation for Robotic Milling Optimizing Stiffness with Sample-Based Planning

Directory of Open Access Journals (Sweden)

Julian Ricardo Diaz Posada

2017-01-01

Full Text Available Optimal and intuitive robotic machining is still a challenge. One of the main reasons for this is the lack of robot stiffness, which is also dependent on the robot positioning in the Cartesian space. To make up for this deficiency and with the aim of increasing robot machining accuracy, this contribution describes a solution approach for optimizing the stiffness over a desired milling path using the free degree of freedom of the machining process. The optimal motion is computed based on the semantic and mathematical interpretation of the manufacturing process modeled on its components: product, process and resource; and by configuring automatically a sample-based motion problem and the transition-based rapid-random tree algorithm for computing an optimal motion. The approach is simulated on a CAM software for a machining path revealing its functionality and outlining future potentials for the optimal motion generation for robotic machining processes.

FPGA-based architecture for motion recovering in real-time

Science.gov (United States)

Arias-Estrada, Miguel; Maya-Rueda, Selene E.; Torres-Huitzil, Cesar

2002-03-01

A key problem in the computer vision field is the measurement of object motion in a scene. The main goal is to compute an approximation of the 3D motion from the analysis of an image sequence. Once computed, this information can be used as a basis to reach higher level goals in different applications. Motion estimation algorithms pose a significant computational load for the sequential processors limiting its use in practical applications. In this work we propose a hardware architecture for motion estimation in real time based on FPGA technology. The technique used for motion estimation is Optical Flow due to its accuracy, and the density of velocity estimation, however other techniques are being explored. The architecture is composed of parallel modules working in a pipeline scheme to reach high throughput rates near gigaflops. The modules are organized in a regular structure to provide a high degree of flexibility to cover different applications. Some results will be presented and the real-time performance will be discussed and analyzed. The architecture is prototyped in an FPGA board with a Virtex device interfaced to a digital imager.

Motion-Based pH Sensing Based on the Cartridge-Case-like Micromotor.

Science.gov (United States)

Su, Yajun; Ge, Ya; Liu, Limei; Zhang, Lina; Liu, Mei; Sun, Yunyu; Zhang, Hui; Dong, Bin

2016-02-17

In this paper, we report a novel cartridge-case-like micromotor. The micromotor, which is fabricated by the template synthesis method, consists of a gelatin shell with platinum nanoparticles decorating its inner surface. Intriguingly, the resulting cartridge-case-like structure exhibits a pH-dependent "open and close" feature, which originates from the pH responsiveness of the gelatin material. On the basis of the catalytic activity of the platinum nanoparticle inside the gelatin shell, the resulting cartridge-case-like structure is capable of moving autonomously in the aqueous solution containing the hydrogen peroxide fuel. More interestingly, we find out that the micromotor can be utilized as a motion-based pH sensor over the whole pH range. The moving velocity of the micromotor increases monotonically with the increase of pH of the analyte solution. Three different factors are considered to be responsible for the proportional relation between the motion speed and pH of the analyte solution: the peroxidase-like and oxidase-like catalytic behavior of the platinum nanoparticle at low and high pH, the volumetric decomposition of the hydrogen peroxide under the basic condition and the pH-dependent catalytic activity of the platinum nanoparticle caused by the swelling/deswelling behavior of the gelatin material. The current work highlights the impact of the material properties on the motion behavior of a micromotor, thus paving the way toward its application in the motion-based sensing field.

Model-based respiratory motion compensation for emission tomography image reconstruction

International Nuclear Information System (INIS)

Reyes, M; Malandain, G; Koulibaly, P M; Gonzalez-Ballester, M A; Darcourt, J

2007-01-01

In emission tomography imaging, respiratory motion causes artifacts in lungs and cardiac reconstructed images, which lead to misinterpretations, imprecise diagnosis, impairing of fusion with other modalities, etc. Solutions like respiratory gating, correlated dynamic PET techniques, list-mode data based techniques and others have been tested, which lead to improvements over the spatial activity distribution in lungs lesions, but which have the disadvantages of requiring additional instrumentation or the need of discarding part of the projection data used for reconstruction. The objective of this study is to incorporate respiratory motion compensation directly into the image reconstruction process, without any additional acquisition protocol consideration. To this end, we propose an extension to the maximum likelihood expectation maximization (MLEM) algorithm that includes a respiratory motion model, which takes into account the displacements and volume deformations produced by the respiratory motion during the data acquisition process. We present results from synthetic simulations incorporating real respiratory motion as well as from phantom and patient data

Residual Motion and Duty Time in Respiratory Gating Radiotherapy Using Individualized or Population-Based Windows

International Nuclear Information System (INIS)

Fuji, Hiroshi; Asada, Yoshihiro; Numano, Masumi; Yamashita, Haruo; Nishimura, Tetsuo; Hashimoto, Takayuki; Harada, Hideyuki; Asakura, Hirofumi; Murayama, Shigeyuki

2009-01-01

Purpose: The efficiency and precision of respiratory gated radiation therapy for tumors is affected by variations in respiration-induced tumor motion. We evaluated the use of individualized and population-based parameters for such treatment. Methods and Materials: External respiratory signal records and images of respiration-induced tumor motion were obtained from 42 patients undergoing respiratory gated radiation therapy for liver tumors. Gating window widths were calculated for each patient, with 2, 4, and 10 mm of residual motion, and the mean was defined as the population-based window width. Residual motions based on population-based and predefined window widths were compared. Duty times based on whole treatment sessions, at various window levels, were calculated. The window level giving the longest duty time was defined as the individualized most efficient level (MEL). MELs were also calculated based on the first 10 breathing cycles. The duty times for population-based MELs (defined as mean MELs) and individualized MELs were compared. Results: Tracks of respiration-induced tumor motion ranged from 3 to 50 mm. Half of the patients had larger actual residual motions than the assigned residual motions. Duty times were greater when based on individualized, rather than population-based, window widths. The MELs established during whole treatment sessions for 2 mm and 4 mm of residual motion gave significantly increased duty times, whereas those calculated using the first 10 breathing cycles showed only marginal increases. Conclusions: Using individualized window widths and levels provided more precise and efficient respiratory gated radiation therapy. However, methods for predicting individualized window levels before treatment remain to be explored.

State Generation Method for Humanoid Motion Planning Based on Genetic Algorithm

Directory of Open Access Journals (Sweden)

Xuyang Wang

2012-05-01

Full Text Available A new approach to generate the original motion data for humanoid motion planning is presented in this paper. And a state generator is developed based on the genetic algorithm, which enables users to generate various motion states without using any reference motion data. By specifying various types of constraints such as configuration constraints and contact constraints, the state generator can generate stable states that satisfy the constraint conditions for humanoid robots. To deal with the multiple constraints and inverse kinematics, the state generation is finally simplified as a problem of optimizing and searching. In our method, we introduce a convenient mathematic representation for the constraints involved in the state generator, and solve the optimization problem with the genetic algorithm to acquire a desired state. To demonstrate the effectiveness and advantage of the method, a number of motion states are generated according to the requirements of the motion.

State Generation Method for Humanoid Motion Planning Based on Genetic Algorithm

Directory of Open Access Journals (Sweden)

Xuyang Wang

2008-11-01

Full Text Available A new approach to generate the original motion data for humanoid motion planning is presented in this paper. And a state generator is developed based on the genetic algorithm, which enables users to generate various motion states without using any reference motion data. By specifying various types of constraints such as configuration constraints and contact constraints, the state generator can generate stable states that satisfy the constraint conditions for humanoid robots.To deal with the multiple constraints and inverse kinematics, the state generation is finally simplified as a problem of optimizing and searching. In our method, we introduce a convenient mathematic representation for the constraints involved in the state generator, and solve the optimization problem with the genetic algorithm to acquire a desired state. To demonstrate the effectiveness and advantage of the method, a number of motion states are generated according to the requirements of the motion.

Alpha motion based on a motion detector, but not on the Müller-Lyer illusion

Science.gov (United States)

Suzuki, Masahiro

2014-07-01

This study examined the mechanism of alpha motion, the apparent motion of the Müller-Lyer figure's shaft that occurs when the arrowheads and arrow tails are alternately presented. The following facts were found: (a) reduced exposure duration decreased the amount of alpha motion, and this phenomenon was not explainable by the amount of the Müller-Lyer illusion; (b) the motion aftereffect occurred after adaptation to alpha motion; (c) occurrence of alpha motion became difficult when the temporal frequency increased, and this characteristic of alpha motion was similar to the characteristic of a motion detector that motion detection became difficult when the temporal frequency increased from the optimal frequency. These findings indicated that alpha motion occurs on the basis of a motion detector but not on the Müller-Lyer illusion, and that the mechanism of alpha motion is the same as that of general motion perception.

3D fluoroscopic image estimation using patient-specific 4DCBCT-based motion models

International Nuclear Information System (INIS)

Dhou, S; Hurwitz, M; Cai, W; Rottmann, J; Williams, C; Wagar, M; Berbeco, R; Lewis, J H; Mishra, P; Li, R; Ionascu, D

2015-01-01

3D fluoroscopic images represent volumetric patient anatomy during treatment with high spatial and temporal resolution. 3D fluoroscopic images estimated using motion models built using 4DCT images, taken days or weeks prior to treatment, do not reliably represent patient anatomy during treatment. In this study we developed and performed initial evaluation of techniques to develop patient-specific motion models from 4D cone-beam CT (4DCBCT) images, taken immediately before treatment, and used these models to estimate 3D fluoroscopic images based on 2D kV projections captured during treatment. We evaluate the accuracy of 3D fluoroscopic images by comparison to ground truth digital and physical phantom images. The performance of 4DCBCT-based and 4DCT-based motion models are compared in simulated clinical situations representing tumor baseline shift or initial patient positioning errors. The results of this study demonstrate the ability for 4DCBCT imaging to generate motion models that can account for changes that cannot be accounted for with 4DCT-based motion models. When simulating tumor baseline shift and patient positioning errors of up to 5 mm, the average tumor localization error and the 95th percentile error in six datasets were 1.20 and 2.2 mm, respectively, for 4DCBCT-based motion models. 4DCT-based motion models applied to the same six datasets resulted in average tumor localization error and the 95th percentile error of 4.18 and 5.4 mm, respectively. Analysis of voxel-wise intensity differences was also conducted for all experiments. In summary, this study demonstrates the feasibility of 4DCBCT-based 3D fluoroscopic image generation in digital and physical phantoms and shows the potential advantage of 4DCBCT-based 3D fluoroscopic image estimation when there are changes in anatomy between the time of 4DCT imaging and the time of treatment delivery. (paper)

Mode extraction on wind turbine blades via phase-based video motion estimation

Science.gov (United States)

Sarrafi, Aral; Poozesh, Peyman; Niezrecki, Christopher; Mao, Zhu

2017-04-01

In recent years, image processing techniques are being applied more often for structural dynamics identification, characterization, and structural health monitoring. Although as a non-contact and full-field measurement method, image processing still has a long way to go to outperform other conventional sensing instruments (i.e. accelerometers, strain gauges, laser vibrometers, etc.,). However, the technologies associated with image processing are developing rapidly and gaining more attention in a variety of engineering applications including structural dynamics identification and modal analysis. Among numerous motion estimation and image-processing methods, phase-based video motion estimation is considered as one of the most efficient methods regarding computation consumption and noise robustness. In this paper, phase-based video motion estimation is adopted for structural dynamics characterization on a 2.3-meter long Skystream wind turbine blade, and the modal parameters (natural frequencies, operating deflection shapes) are extracted. Phase-based video processing adopted in this paper provides reliable full-field 2-D motion information, which is beneficial for manufacturing certification and model updating at the design stage. The phase-based video motion estimation approach is demonstrated through processing data on a full-scale commercial structure (i.e. a wind turbine blade) with complex geometry and properties, and the results obtained have a good correlation with the modal parameters extracted from accelerometer measurements, especially for the first four bending modes, which have significant importance in blade characterization.

Improved frame-based estimation of head motion in PET brain imaging

International Nuclear Information System (INIS)

Mukherjee, J. M.; Lindsay, C.; King, M. A.; Licho, R.; Mukherjee, A.; Olivier, P.; Shao, L.

2016-01-01

not susceptible to motion introduced between CT and PET acquisitions. Conclusions: The authors have shown that they can estimate motion for frames with time intervals as short as 5 s using nonattenuation corrected reconstructed FDG PET brain images. Intraframe motion in 60-s frames causes degradation of accuracy to about 2 mm based on the motion type.

Improved frame-based estimation of head motion in PET brain imaging

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, J. M., E-mail: joyeeta.mitra@umassmed.edu; Lindsay, C.; King, M. A.; Licho, R. [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States); Mukherjee, A. [Aware, Inc., Bedford, Massachusetts 01730 (United States); Olivier, P. [Philips Medical Systems, Cleveland, Ohio 44143 (United States); Shao, L. [ViewRay, Oakwood Village, Ohio 44146 (United States)

2016-05-15

not susceptible to motion introduced between CT and PET acquisitions. Conclusions: The authors have shown that they can estimate motion for frames with time intervals as short as 5 s using nonattenuation corrected reconstructed FDG PET brain images. Intraframe motion in 60-s frames causes degradation of accuracy to about 2 mm based on the motion type.

Gaussian particle filter based pose and motion estimation

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

Determination of relative three-dimensional (3D) position, orientation, and relative motion between two reference frames is an important problem in robotic guidance, manipulation, and assembly as well as in other fields such as photogrammetry.A solution to pose and motion estimation problem that uses two-dimensional (2D) intensity images from a single camera is desirable for real-time applications. The difficulty in performing this measurement is that the process of projecting 3D object features to 2D images is a nonlinear transformation. In this paper, the 3D transformation is modeled as a nonlinear stochastic system with the state estimation providing six degrees-of-freedom motion and position values, using line features in image plane as measuring inputs and dual quaternion to represent both rotation and translation in a unified notation. A filtering method called the Gaussian particle filter (GPF) based on the particle filtering concept is presented for 3D pose and motion estimation of a moving target from monocular image sequences. The method has been implemented with simulated data, and simulation results are provided along with comparisons to the extended Kalman filter (EKF) and the unscented Kalman filter (UKF) to show the relative advantages of the GPF. Simulation results showed that GPF is a superior alternative to EKF and UKF.

The fate of task-irrelevant visual motion: perceptual load versus feature-based attention.

Science.gov (United States)

Taya, Shuichiro; Adams, Wendy J; Graf, Erich W; Lavie, Nilli

2009-11-18

We tested contrasting predictions derived from perceptual load theory and from recent feature-based selection accounts. Observers viewed moving, colored stimuli and performed low or high load tasks associated with one stimulus feature, either color or motion. The resultant motion aftereffect (MAE) was used to evaluate attentional allocation. We found that task-irrelevant visual features received less attention than co-localized task-relevant features of the same objects. Moreover, when color and motion features were co-localized yet perceived to belong to two distinct surfaces, feature-based selection was further increased at the expense of object-based co-selection. Load theory predicts that the MAE for task-irrelevant motion would be reduced with a higher load color task. However, this was not seen for co-localized features; perceptual load only modulated the MAE for task-irrelevant motion when this was spatially separated from the attended color location. Our results suggest that perceptual load effects are mediated by spatial selection and do not generalize to the feature domain. Feature-based selection operates to suppress processing of task-irrelevant, co-localized features, irrespective of perceptual load.

Smart Sensor-Based Motion Detection System for Hand Movement Training in Open Surgery.

Science.gov (United States)

Sun, Xinyao; Byrns, Simon; Cheng, Irene; Zheng, Bin; Basu, Anup

2017-02-01

We introduce a smart sensor-based motion detection technique for objective measurement and assessment of surgical dexterity among users at different experience levels. The goal is to allow trainees to evaluate their performance based on a reference model shared through communication technology, e.g., the Internet, without the physical presence of an evaluating surgeon. While in the current implementation we used a Leap Motion Controller to obtain motion data for analysis, our technique can be applied to motion data captured by other smart sensors, e.g., OptiTrack. To differentiate motions captured from different participants, measurement and assessment in our approach are achieved using two strategies: (1) low level descriptive statistical analysis, and (2) Hidden Markov Model (HMM) classification. Based on our surgical knot tying task experiment, we can conclude that finger motions generated from users with different surgical dexterity, e.g., expert and novice performers, display differences in path length, number of movements and task completion time. In order to validate the discriminatory ability of HMM for classifying different movement patterns, a non-surgical task was included in our analysis. Experimental results demonstrate that our approach had 100 % accuracy in discriminating between expert and novice performances. Our proposed motion analysis technique applied to open surgical procedures is a promising step towards the development of objective computer-assisted assessment and training systems.

[Electormagnetic field of the mobile phone base station: case study].

Science.gov (United States)

Bieńkowski, Paweł; Zubrzak, Bartłomiej; Surma, Robert

2011-01-01

The paper presents changes in the electromagnetic field intensity in a school building and its surrounding after the mobile phone base station installation on the roof of the school. The comparison of EMF intensity measured before the base station was launched (electromagnetic background measurement) and after starting its operation (two independent control measurements) is discussed. Analyses of measurements are presented and the authors also propose the method of the electromagnetic field distribution adjustment in the area of radiation antennas side lobe to reduce the intensity of the EMF level in the base station proximity. The presented method involves the regulation of the inclination. On the basis of the measurements, it was found that the EMF intensity increased in the building and its surroundings, but the values measured with wide margins meet the requirements of the Polish law on environmental protection.

Variable disparity-motion estimation based fast three-view video coding

Science.gov (United States)

Bae, Kyung-Hoon; Kim, Seung-Cheol; Hwang, Yong Seok; Kim, Eun-Soo

2009-02-01

In this paper, variable disparity-motion estimation (VDME) based 3-view video coding is proposed. In the encoding, key-frame coding (KFC) based motion estimation and variable disparity estimation (VDE) for effectively fast three-view video encoding are processed. These proposed algorithms enhance the performance of 3-D video encoding/decoding system in terms of accuracy of disparity estimation and computational overhead. From some experiments, stereo sequences of 'Pot Plant' and 'IVO', it is shown that the proposed algorithm's PSNRs is 37.66 and 40.55 dB, and the processing time is 0.139 and 0.124 sec/frame, respectively.

Software for project-based learning of robot motion planning

Science.gov (United States)

Moll, Mark; Bordeaux, Janice; Kavraki, Lydia E.

2013-12-01

Motion planning is a core problem in robotics concerned with finding feasible paths for a given robot. Motion planning algorithms perform a search in the high-dimensional continuous space of robot configurations and exemplify many of the core algorithmic concepts of search algorithms and associated data structures. Motion planning algorithms can be explained in a simplified two-dimensional setting, but this masks many of the subtleties and complexities of the underlying problem. We have developed software for project-based learning of motion planning that enables deep learning. The projects that we have developed allow advanced undergraduate students and graduate students to reflect on the performance of existing textbook algorithms and their own variations on such algorithms. Formative assessment has been conducted at three institutions. The core of the software used for this teaching module is also used within the Robot Operating System, a widely adopted platform by the robotics research community. This allows for transfer of knowledge and skills to robotics research projects involving a large variety robot hardware platforms.

Patient cloth with motion recognition sensors based on flexible piezoelectric materials.

Science.gov (United States)

Youngsu Cha; Kihyuk Nam; Doik Kim

2017-07-01

In this paper, we introduce a patient cloth for position monitoring using motion recognition sensors based on flexible piezoelectric materials. The motion recognition sensors are embedded in three parts, which are the knee, hip and back, in the patient cloth. We use polyvinylidene fluoride (PVDF) as the flexible piezoelectric material for the sensors. By using the piezoelectric effect of the PVDF, we detect electrical signals when the cloth is bent or extended. We analyze the sensing values for our human motions by processing the sensor outputs in a custom-made program. Specifically, we focus on the transitions between standing and sitting, and sitting knee extension and supine position, which are important motions for patient monitoring.

Environmental Metabolic Footprinting (EMF) vs. half-life: a new and integrative proxy for the discrimination between control and pesticides exposed sediments in order to further characterise pesticides' environmental impact.

Science.gov (United States)

Salvia, Marie-Virginie; Ben Jrad, Amani; Raviglione, Delphine; Zhou, Yuxiang; Bertrand, Cédric

2017-06-28

Pesticides are regularly used for a variety of applications and are disseminated throughout the environment. These substances may have significant negative impacts. To date, the half-life, t 1/2 , was often used to study the fate of pesticides in environmental matrices (water, soil, sediment). However, this value gives limited information. First, it does not evaluate the formation of by-products, resulting in the need for additional experiments to be performed to evaluate biodegradation and biotransformation products. T 1/2 also fails to consider the chemical's impact on biodiversity. Resilience time, a new and integrative proxy, was recently proposed as an alternative to t 1/2 , with the potential to evaluate all the post-application effects of the chemical on the environment. The 'Environmental Metabolic Footprinting' (EMF) approach, giving an idea of the resilience time, was used to evaluate the impact of botanicals on soil. The goal is to optimise the EMF to study the impact of a microbial insecticide, the Bacillus thuringiensis israelensis (Bti), on sediment. The difficulty of this work lies in the commercial solution of Bti that is really complex, and this complexity yields chromatograms that are extremely difficult to interpret; t 1/2 cannot be used. No methodologies currently exist to monitor the impact of these compounds on the environment. We will test the EMF to determine if it is sensitive enough to tolerate such complex mixtures. A pure chemical insecticide, the α-cypermethrin, will be also studied. The article shows that the EMF is able to distinguish meta-metabolome differences between control and exposed (with Bti) sediments.

Nuclear Energy Response in the EMF27 Study

International Nuclear Information System (INIS)

Kim, Son H.; Wada, Kenichi; Kurosawa, Atsushi; Roberts, Matthew

2014-01-01

The nuclear energy response for mitigating global climate change across eighteen participating models of the EMF27 study is investigated. Diverse perspectives on the future role of nuclear power in the global energy system are evident in the broad range of nuclear power contributions from participating models of the study. In the Baseline scenario without climate policy, nuclear electricity generation and shares span 0 - 66 EJ/ year and 0 - 25% in 2100 for all models, with a median nuclear electricity generation of 39 EJ/year (1,389 GWe at 90% capacity factor) and median share of 9%. The role of nuclear energy increased under the climate policy scenarios. The median of nuclear energy use across all models doubled in the 450 ppm CO2e scenario with a nuclear electricity generation of 67 EJ/year (2,352 GWe at 90% capacity factor) and share of 17% in 2100. The broad range of nuclear electricity generation (11 - 214 EJ/year) and shares (2 - 38%) in 2100 of the 450 ppm CO2e scenario reflect differences in the technology choice behavior, technology assumptions and competitiveness of low carbon technologies. Greater clarification of nuclear fuel cycle issues and risk factors associated with nuclear energy use are necessary for understanding the nuclear deployment constraints imposed in models and for improving the assessment of the nuclear energy potential in addressing climate change

Thermodynamic properties of liquid silver-antimony alloys determined from emf measurements

International Nuclear Information System (INIS)

Krzyzak, Agnieszka; Fitzner, Krzysztof

2004-01-01

The thermodynamic properties of the liquid Ag-Sb alloys were determined using solid oxide galvanic cells with zirconia electrolyte. The emfs of the cells:Ag x Sb (1-x), Sb 2 O 3 /O 2- /airwere measured in the temperatures range 950-1100K in the whole range of the alloy compositions.First, the Gibbs free energy of formation of liquid Sb 2 O 3 from pure elements was derived:ΔG o f(Sb2O3) (J/mol)=-687100+243.23T.Next, the activities of antimony were measured as a function of the alloy compositions, x. Redlich-Kister polynomial expansion was used to describe the thermodynamic properties of the liquid phase. From the model equations the limiting value of the logarithm of activity coefficient of antimony in silver was obtained as a function of temperature:lnγ Sb 0 =-3812.5/T+0.4112.The obtained results were compared with the experimental values reported in the literature

Design and Evaluation of Accelerometer based Motional Feedback

DEFF Research Database (Denmark)

Schneider, Henrik; Pranjic, Emilio; Agerkvist, Finn T.

2015-01-01

and enable radical design changes in the loudspeaker which can lead to efficiency improvements. In combination this has motivated a revisit of the accelerometer based motional feedback technique. Experimental results on a 8 inch subwoofer show that the total harmonic distortion can be significantly reduced...

Auditory Motion Elicits a Visual Motion Aftereffect.

Science.gov (United States)

Berger, Christopher C; Ehrsson, H Henrik

2016-01-01

The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect-an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

Auditory Motion Elicits a Visual Motion Aftereffect

Directory of Open Access Journals (Sweden)

Christopher C. Berger

2016-12-01

Full Text Available The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect—an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

Biophysical aspects of the influence of electromagnetic fields (EMF on the human body Influencia de los campos electromagnéticos en el organismo humano: aspectos biofísicos

Directory of Open Access Journals (Sweden)

Napaleon Hernández

1993-03-01

Full Text Available

Some historical aspects of biomagnetism and of the various steps that led to the development of bioelectricity and electro technique are summarized. Alterations observed in individuals working for long periods of time in contact with artificial EMF are described as well as the correlation between natural EMF and accidentality. The utilization of EMF for therapeutic purposes 15 reviewed and some considerations are given to the so called ";bioenergetic medicine"; that employs light, laser, sound, electricity and magnetism. A warning 15 made against the indiscriminate therapeutic use of EMF by practitioners without proper training; the need for solid research which may support the development of this area of medicine Is emphasized.

En este artículo se resumen algunos aspectos históricos del biomagnetismo y de las etapas que condujeron al desarrollo de la bioelectricidad y la electrotécnica. Se describen las alteraciones observadas en quienes trabajan por períodos prolongados en contacto con campos electromagnéticos (CEM artificiales y la correlación entre los CEM naturales y la accidentalidad. Se revisan la utilización de los CEM con fines curativos y la escuela llamada ";bioenergética"; que utiliza terapéuticamente la luz, el láser, el sonido, la electricidad y el magnetismo. Se previene contra el uso terapéutico Indiscriminado de los CEM por personas sin adecuada formación y se hace énfasis en la necesidad de adelantar Investigaciones serias que sustenten este desarrollo de la medicina.

Event-based motion correction for PET transmission measurements with a rotating point source

International Nuclear Information System (INIS)

Zhou, Victor W; Kyme, Andre Z; Meikle, Steven R; Fulton, Roger

2011-01-01

Accurate attenuation correction is important for quantitative positron emission tomography (PET) studies. When performing transmission measurements using an external rotating radioactive source, object motion during the transmission scan can distort the attenuation correction factors computed as the ratio of the blank to transmission counts, and cause errors and artefacts in reconstructed PET images. In this paper we report a compensation method for rigid body motion during PET transmission measurements, in which list mode transmission data are motion corrected event-by-event, based on known motion, to ensure that all events which traverse the same path through the object are recorded on a common line of response (LOR). As a result, the motion-corrected transmission LOR may record a combination of events originally detected on different LORs. To ensure that the corresponding blank LOR records events from the same combination of contributing LORs, the list mode blank data are spatially transformed event-by-event based on the same motion information. The number of counts recorded on the resulting blank LOR is then equivalent to the number of counts that would have been recorded on the corresponding motion-corrected transmission LOR in the absence of any attenuating object. The proposed method has been verified in phantom studies with both stepwise movements and continuous motion. We found that attenuation maps derived from motion-corrected transmission and blank data agree well with those of the stationary phantom and are significantly better than uncorrected attenuation data.

Sickness absence from 1978 to 1992 of Electricite de France (EDF) workers exposed to ELF-EMF: the substation group

International Nuclear Information System (INIS)

Souques, M.; Dab, W.; Lambrozo, J.; Chevalier, A.; Coing, F.

1996-01-01

Electromagnetic fields are suspected of many health effects, including cancers, immunity and fertility disorders, congenital malformations, suicides and depression.... Although the results of all studies are contradictory and no biological mechanism has been found, populations are concerned about this matter. This study analyzes the absence from work of some EDF employees who are a priori the most professionally exposed to ELF EMF. Absence from work is taken as an health indicator. Although it is not specific, it can be predictive of serious health problems. The specific context of EDF has made it possible to collect and analyze the medical aspect of absence from work, that is rare in France. We were interested with employees working with high voltage (over 90 kV). Three job categories have been selected: live line workers, substation maintenance workers and substation exploitation workers (called in the company the ATEX). The first group concerned the live linemen and the results were exposed previously. It appeared they had more accidents at work, but this was more related to the job of lineman rather than to the EMF exposure. Nevertheless, substation workers have an exposure less intensive but longer than live linemen. We present here the result about the absenteeism of the substation workers, maintenance and exploitation. (author)

Mitigation of motion artifacts in CBCT of lung tumors based on tracked tumor motion during CBCT acquisition

International Nuclear Information System (INIS)

Lewis, John H; Li Ruijiang; Jia Xun; Watkins, W Tyler; Song, William Y; Jiang, Steve B; Lou, Yifei

2011-01-01

An algorithm capable of mitigating respiratory motion blurring artifacts in cone-beam computed tomography (CBCT) lung tumor images based on the motion of the tumor during the CBCT scan is developed. The tumor motion trajectory and probability density function (PDF) are reconstructed from the acquired CBCT projection images using a recently developed algorithm Lewis et al (2010 Phys. Med. Biol. 55 2505-22). Assuming that the effects of motion blurring can be represented by convolution of the static lung (or tumor) anatomy with the motion PDF, a cost function is defined, consisting of a data fidelity term and a total variation regularization term. Deconvolution is performed through iterative minimization of this cost function. The algorithm was tested on digital respiratory phantom, physical respiratory phantom and patient data. A clear qualitative improvement is evident in the deblurred images as compared to the motion-blurred images for all cases. Line profiles show that the tumor boundaries are more accurately and clearly represented in the deblurred images. The normalized root-mean-squared error between the images used as ground truth and the motion-blurred images are 0.29, 0.12 and 0.30 in the digital phantom, physical phantom and patient data, respectively. Deblurring reduces the corresponding values to 0.13, 0.07 and 0.19. Application of a -700 HU threshold to the digital phantom results in tumor dimension measurements along the superior-inferior axis of 2.8, 1.8 and 1.9 cm in the motion-blurred, ground truth and deblurred images, respectively. Corresponding values for the physical phantom are 3.4, 2.7 and 2.7 cm. A threshold of -500 HU applied to the patient case gives measurements of 3.1, 1.6 and 1.7 cm along the SI axis in the CBCT, 4DCT and deblurred images, respectively. This technique could provide more accurate information about a lung tumor's size and shape on the day of treatment.

Surface EMG signals based motion intent recognition using multi-layer ELM

Science.gov (United States)

Wang, Jianhui; Qi, Lin; Wang, Xiao

2017-11-01

The upper-limb rehabilitation robot is regard as a useful tool to help patients with hemiplegic to do repetitive exercise. The surface electromyography (sEMG) contains motion information as the electric signals are generated and related to nerve-muscle motion. These sEMG signals, representing human's intentions of active motions, are introduced into the rehabilitation robot system to recognize upper-limb movements. Traditionally, the feature extraction is an indispensable part of drawing significant information from original signals, which is a tedious task requiring rich and related experience. This paper employs a deep learning scheme to extract the internal features of the sEMG signals using an advanced Extreme Learning Machine based auto-encoder (ELMAE). The mathematical information contained in the multi-layer structure of the ELM-AE is used as the high-level representation of the internal features of the sEMG signals, and thus a simple ELM can post-process the extracted features, formulating the entire multi-layer ELM (ML-ELM) algorithm. The method is employed for the sEMG based neural intentions recognition afterwards. The case studies show the adopted deep learning algorithm (ELM-AE) is capable of yielding higher classification accuracy compared to the Principle Component Analysis (PCA) scheme in 5 different types of upper-limb motions. This indicates the effectiveness and the learning capability of the ML-ELM in such motion intent recognition applications.

Temporal regularization of ultrasound-based liver motion estimation for image-guided radiation therapy

Energy Technology Data Exchange (ETDEWEB)

O’Shea, Tuathan P., E-mail: tuathan.oshea@icr.ac.uk; Bamber, Jeffrey C.; Harris, Emma J. [Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS foundation Trust, Sutton, London SM2 5PT (United Kingdom)

2016-01-15

Purpose: Ultrasound-based motion estimation is an expanding subfield of image-guided radiation therapy. Although ultrasound can detect tissue motion that is a fraction of a millimeter, its accuracy is variable. For controlling linear accelerator tracking and gating, ultrasound motion estimates must remain highly accurate throughout the imaging sequence. This study presents a temporal regularization method for correlation-based template matching which aims to improve the accuracy of motion estimates. Methods: Liver ultrasound sequences (15–23 Hz imaging rate, 2.5–5.5 min length) from ten healthy volunteers under free breathing were used. Anatomical features (blood vessels) in each sequence were manually annotated for comparison with normalized cross-correlation based template matching. Five sequences from a Siemens Acuson™ scanner were used for algorithm development (training set). Results from incremental tracking (IT) were compared with a temporal regularization method, which included a highly specific similarity metric and state observer, known as the α–β filter/similarity threshold (ABST). A further five sequences from an Elekta Clarity™ system were used for validation, without alteration of the tracking algorithm (validation set). Results: Overall, the ABST method produced marked improvements in vessel tracking accuracy. For the training set, the mean and 95th percentile (95%) errors (defined as the difference from manual annotations) were 1.6 and 1.4 mm, respectively (compared to 6.2 and 9.1 mm, respectively, for IT). For each sequence, the use of the state observer leads to improvement in the 95% error. For the validation set, the mean and 95% errors for the ABST method were 0.8 and 1.5 mm, respectively. Conclusions: Ultrasound-based motion estimation has potential to monitor liver translation over long time periods with high accuracy. Nonrigid motion (strain) and the quality of the ultrasound data are likely to have an impact on tracking

Reference geometry-based detection of (4D-)CT motion artifacts: a feasibility study

Science.gov (United States)

Werner, René; Gauer, Tobias

2015-03-01

Respiration-correlated computed tomography (4D or 3D+t CT) can be considered as standard of care in radiation therapy treatment planning for lung and liver lesions. The decision about an application of motion management devices and the estimation of patient-specific motion effects on the dose distribution relies on precise motion assessment in the planning 4D CT data { which is impeded in case of CT motion artifacts. The development of image-based/post-processing approaches to reduce motion artifacts would benefit from precise detection and localization of the artifacts. Simple slice-by-slice comparison of intensity values and threshold-based analysis of related metrics suffer from- depending on the threshold- high false-positive or -negative rates. In this work, we propose exploiting prior knowledge about `ideal' (= artifact free) reference geometries to stabilize metric-based artifact detection by transferring (multi-)atlas-based concepts to this specific task. Two variants are introduced and evaluated: (S1) analysis and comparison of warped atlas data obtained by repeated non-linear atlas-to-patient registration with different levels of regularization; (S2) direct analysis of vector field properties (divergence, curl magnitude) of the atlas-to-patient transformation. Feasibility of approaches (S1) and (S2) is evaluated by motion-phantom data and intra-subject experiments (four patients) as well as - adopting a multi-atlas strategy- inter-subject investigations (twelve patients involved). It is demonstrated that especially sorting/double structure artifacts can be precisely detected and localized by (S1). In contrast, (S2) suffers from high false positive rates.

Validity of at home model predictions as a proxy for personal exposure to radiofrequency electromagnetic fields from mobile phone base stations.

Science.gov (United States)

Martens, Astrid L; Bolte, John F B; Beekhuizen, Johan; Kromhout, Hans; Smid, Tjabe; Vermeulen, Roel C H

2015-10-01

Epidemiological studies on the potential health effects of RF-EMF from mobile phone base stations require efficient and accurate exposure assessment methods. Previous studies have demonstrated that the 3D geospatial model NISMap is able to rank locations by indoor and outdoor RF-EMF exposure levels. This study extends on previous work by evaluating the suitability of using NISMap to estimate indoor RF-EMF exposure levels at home as a proxy for personal exposure to RF-EMF from mobile phone base stations. For 93 individuals in the Netherlands we measured personal exposure to RF-EMF from mobile phone base stations during a 24h period using an EME-SPY 121 exposimeter. Each individual kept a diary from which we extracted the time spent at home and in the bedroom. We used NISMap to model exposure at the home address of the participant (at bedroom height). We then compared model predictions with measurements for the 24h period, when at home, and in the bedroom by the Spearman correlation coefficient (rsp) and by calculating specificity and sensitivity using the 90th percentile of the exposure distribution as a cutpoint for high exposure. We found a low to moderate rsp of 0.36 for the 24h period, 0.51 for measurements at home, and 0.41 for measurements in the bedroom. The specificity was high (0.9) but with a low sensitivity (0.3). These results indicate that a meaningful ranking of personal RF-EMF can be achieved, even though the correlation between model predictions and 24h personal RF-EMF measurements is lower than with at home measurements. However, the use of at home RF-EMF field predictions from mobile phone base stations in epidemiological studies leads to significant exposure misclassification that will result in a loss of statistical power to detect health effects. Copyright © 2015 Elsevier Inc. All rights reserved.

Magnetic Resonance-based Motion Correction for Quantitative PET in Simultaneous PET-MR Imaging.

Science.gov (United States)

Rakvongthai, Yothin; El Fakhri, Georges

2017-07-01

Motion degrades image quality and quantitation of PET images, and is an obstacle to quantitative PET imaging. Simultaneous PET-MR offers a tool that can be used for correcting the motion in PET images by using anatomic information from MR imaging acquired concurrently. Motion correction can be performed by transforming a set of reconstructed PET images into the same frame or by incorporating the transformation into the system model and reconstructing the motion-corrected image. Several phantom and patient studies have validated that MR-based motion correction strategies have great promise for quantitative PET imaging in simultaneous PET-MR. Copyright © 2017 Elsevier Inc. All rights reserved.

Motion based parsing for video from observational psychology

Science.gov (United States)

Kokaram, Anil; Doyle, Erika; Lennon, Daire; Joyeux, Laurent; Fuller, Ray

2006-01-01

In Psychology it is common to conduct studies involving the observation of humans undertaking some task. The sessions are typically recorded on video and used for subjective visual analysis. The subjective analysis is tedious and time consuming, not only because much useless video material is recorded but also because subjective measures of human behaviour are not necessarily repeatable. This paper presents tools using content based video analysis that allow automated parsing of video from one such study involving Dyslexia. The tools rely on implicit measures of human motion that can be generalised to other applications in the domain of human observation. Results comparing quantitative assessment of human motion with subjective assessment are also presented, illustrating that the system is a useful scientific tool.

An Electromagnetic Gauge Technique for Measuring Shocked Particle Velocity in Electrically Conductive Samples

Science.gov (United States)

Cheng, David; Yoshinaka, Akio

2014-11-01

Electromagnetic velocity (EMV) gauges are a class of film gauges which permit the direct in-situ measurement of shocked material flow velocity. The active sensing element, typically a metallic foil, requires exposure to a known external magnetic field in order to produce motional electromotive force (emf). Due to signal distortion caused by mutual inductance between sample and EMV gauge, this technique is typically limited to shock waves in non-conductive materials. In conductive samples, motional emf generated in the EMV gauge has to be extracted from the measured signal which results from the combined effects of both motional emf and voltage changes from induced currents. An electromagnetic technique is presented which analytically models the dynamics of induced current between a copper disk moving as a rigid body with constant 1D translational velocity toward an EMV gauge, where both disk and gauge are exposed to a uniform external static magnetic field. The disk is modelled as a magnetic dipole loop where its Foucault current is evaluated from the characteristics of the fields, whereas the EMV gauge is modelled as a circuit loop immersed in the field of the magnetic dipole loop, the intensity of which is calculated as a function of space and, implicitly, time. Equations of mutual induction are derived and the current induced in the EMV gauge loop is solved, allowing discrimination of the motional emf. Numerical analysis is provided for the step response of the induced EMV gauge current with respect to the Foucault current in the moving copper sample.

The Toggle Local Planner for sampling-based motion planning

KAUST Repository

Denny, Jory; Amato, Nancy M.

2012-01-01

Sampling-based solutions to the motion planning problem, such as the probabilistic roadmap method (PRM), have become commonplace in robotics applications. These solutions are the norm as the dimensionality of the planning space grows, i.e., d > 5

Visual complexity, player experience, performance and physical exertion in motion-based games for older adults

OpenAIRE

Smeddinck, Jan D.; Gerling, Kathrin M.; Tiemkeo, Saranat

2013-01-01

Motion-based video games can have a variety of benefits for the players and are increasingly applied in physical therapy, rehabilitation and prevention for older adults. However, little is known about how this audience experiences playing such games, how the player experience affects the way older adults interact with motion-based games, and how this can relate to therapy goals. In our work, we decompose the player experience of older adults engaging with motion-based games, focusing on the e...

SU-E-J-01: 3D Fluoroscopic Image Estimation From Patient-Specific 4DCBCT-Based Motion Models

International Nuclear Information System (INIS)

Dhou, S; Hurwitz, M; Lewis, J; Mishra, P

2014-01-01

Purpose: 3D motion modeling derived from 4DCT images, taken days or weeks before treatment, cannot reliably represent patient anatomy on the day of treatment. We develop a method to generate motion models based on 4DCBCT acquired at the time of treatment, and apply the model to estimate 3D time-varying images (referred to as 3D fluoroscopic images). Methods: Motion models are derived through deformable registration between each 4DCBCT phase, and principal component analysis (PCA) on the resulting displacement vector fields. 3D fluoroscopic images are estimated based on cone-beam projections simulating kV treatment imaging. PCA coefficients are optimized iteratively through comparison of these cone-beam projections and projections estimated based on the motion model. Digital phantoms reproducing ten patient motion trajectories, and a physical phantom with regular and irregular motion derived from measured patient trajectories, are used to evaluate the method in terms of tumor localization, and the global voxel intensity difference compared to ground truth. Results: Experiments included: 1) assuming no anatomic or positioning changes between 4DCT and treatment time; and 2) simulating positioning and tumor baseline shifts at the time of treatment compared to 4DCT acquisition. 4DCBCT were reconstructed from the anatomy as seen at treatment time. In case 1) the tumor localization error and the intensity differences in ten patient were smaller using 4DCT-based motion model, possible due to superior image quality. In case 2) the tumor localization error and intensity differences were 2.85 and 0.15 respectively, using 4DCT-based motion models, and 1.17 and 0.10 using 4DCBCT-based models. 4DCBCT performed better due to its ability to reproduce daily anatomical changes. Conclusion: The study showed an advantage of 4DCBCT-based motion models in the context of 3D fluoroscopic images estimation. Positioning and tumor baseline shift uncertainties were mitigated by the 4DCBCT-based

Sequential Ground Motion Effects on the Behavior of a Base-Isolated RCC Building

Directory of Open Access Journals (Sweden)

Zhi Zheng

2017-01-01

Full Text Available The sequential ground motion effects on the dynamic responses of reinforced concrete containment (RCC buildings with typical isolators are studied in this paper. Although the base isolation technique is developed to guarantee the security and integrity of RCC buildings under single earthquakes, seismic behavior of base-isolated RCC buildings under sequential ground motions is deficient. Hence, an ensemble of as-recorded sequential ground motions is employed to study the effect of including aftershocks on the seismic evaluation of base-isolated RCC buildings. The results indicate that base isolation can significantly attenuate the earthquake shaking of the RCC building under not only single earthquakes but also seismic sequences. It is also found that the adverse aftershock effect on the RCC can be reduced due to the base isolation applied to the RCC. More importantly, the study indicates that disregarding aftershocks can induce significant underestimation of the isolator displacement for base-isolated RCC buildings.

Motion-compensated optical coherence tomography using envelope-based surface detection and Kalman-based prediction

Science.gov (United States)

Irsch, Kristina; Lee, Soohyun; Bose, Sanjukta N.; Kang, Jin U.

2018-02-01

We present an optical coherence tomography (OCT) imaging system that effectively compensates unwanted axial motion with micron-scale accuracy. The OCT system is based on a swept-source (SS) engine (1060-nm center wavelength, 100-nm full-width sweeping bandwidth, and 100-kHz repetition rate), with axial and lateral resolutions of about 4.5 and 8.5 microns respectively. The SS-OCT system incorporates a distance sensing method utilizing an envelope-based surface detection algorithm. The algorithm locates the target surface from the B-scans, taking into account not just the first or highest peak but the entire signature of sequential A-scans. Subsequently, a Kalman filter is applied as predictor to make up for system latencies, before sending the calculated position information to control a linear motor, adjusting and maintaining a fixed system-target distance. To test system performance, the motioncorrection algorithm was compared to earlier, more basic peak-based surface detection methods and to performing no motion compensation. Results demonstrate increased robustness and reproducibility, particularly noticeable in multilayered tissues, while utilizing the novel technique. Implementing such motion compensation into clinical OCT systems may thus improve the reliability of objective and quantitative information that can be extracted from OCT measurements.

EMF 7 model comparisons: key relationships and parameters

Energy Technology Data Exchange (ETDEWEB)

Hickman, B.G.

1983-12-01

A simplified textbook model of aggregate demand and supply interprets the similarities and differences in the price and income responses of the various EMF 7 models to oil and policy shocks. The simplified model is a marriage of Hicks' classic IS-LM formulation of the Keynesian theory of effective demand with a rudimentary model of aggregate supply, combining a structural Phillips curve for wage determination and a markup theory of price determination. The reduced-form income equation from the fix-price IS-LM model is used to define an aggregate demand (AD) locus in P-Y space, showing alternative pairs of the implicit GNP deflator and real GNP which would simultaneously satisfy the saving-investment identity and the condition for money market equilibrium. An aggregate supply (AS) schedule is derived by a similar reduction of relations between output and labor demand, unemployment and wage inflation, and the wage-price-productivity nexus governing markup pricing. Given a particular econometric model it is possible to derive IS and LM curves algebraically. The resulting locuses would show alternative combinations of interest rate and real income which equilibrate real income identity on the IS side and the demand and supply of money on the LM side. By further substitution the reduced form fix-price income relation could be obtained for direct quantification of the AD locus. The AS schedule is obtainable by algebraic reduction of the structural supply side equations.

The instantaneous linear motion information measurement method based on inertial sensors for ships

Science.gov (United States)

Yang, Xu; Huang, Jing; Gao, Chen; Quan, Wei; Li, Ming; Zhang, Yanshun

2018-05-01

Ship instantaneous line motion information is the important foundation for ship control, which needs to be measured accurately. For this purpose, an instantaneous line motion measurement method based on inertial sensors is put forward for ships. By introducing a half-fixed coordinate system to realize the separation between instantaneous line motion and ship master movement, the instantaneous line motion acceleration of ships can be obtained with higher accuracy. Then, the digital high-pass filter is applied to suppress the velocity error caused by the low frequency signal such as schuler period. Finally, the instantaneous linear motion displacement of ships can be measured accurately. Simulation experimental results show that the method is reliable and effective, and can realize the precise measurement of velocity and displacement of instantaneous line motion for ships.

Real-time DSP implementation for MRF-based video motion detection.

Science.gov (United States)

Dumontier, C; Luthon, F; Charras, J P

1999-01-01

This paper describes the real time implementation of a simple and robust motion detection algorithm based on Markov random field (MRF) modeling, MRF-based algorithms often require a significant amount of computations. The intrinsic parallel property of MRF modeling has led most of implementations toward parallel machines and neural networks, but none of these approaches offers an efficient solution for real-world (i.e., industrial) applications. Here, an alternative implementation for the problem at hand is presented yielding a complete, efficient and autonomous real-time system for motion detection. This system is based on a hybrid architecture, associating pipeline modules with one asynchronous module to perform the whole process, from video acquisition to moving object masks visualization. A board prototype is presented and a processing rate of 15 images/s is achieved, showing the validity of the approach.

Multivariate Autoregressive Model Based Heart Motion Prediction Approach for Beating Heart Surgery

Directory of Open Access Journals (Sweden)

Fan Liang

2013-02-01

Full Text Available A robotic tool can enable a surgeon to conduct off-pump coronary artery graft bypass surgery on a beating heart. The robotic tool actively alleviates the relative motion between the point of interest (POI on the heart surface and the surgical tool and allows the surgeon to operate as if the heart were stationary. Since the beating heart's motion is relatively high-band, with nonlinear and nonstationary characteristics, it is difficult to follow. Thus, precise beating heart motion prediction is necessary for the tracking control procedure during the surgery. In the research presented here, we first observe that Electrocardiography (ECG signal contains the causal phase information on heart motion and non-stationary heart rate dynamic variations. Then, we investigate the relationship between ECG signal and beating heart motion using Granger Causality Analysis, which describes the feasibility of the improved prediction of heart motion. Next, we propose a nonlinear time-varying multivariate vector autoregressive (MVAR model based adaptive prediction method. In this model, the significant correlation between ECG and heart motion enables the improvement of the prediction of sharp changes in heart motion and the approximation of the motion with sufficient detail. Dual Kalman Filters (DKF estimate the states and parameters of the model, respectively. Last, we evaluate the proposed algorithm through comparative experiments using the two sets of collected vivo data.

Optical and Acoustic Sensor-Based 3D Ball Motion Estimation for Ball Sport Simulators †

Directory of Open Access Journals (Sweden)

Sang-Woo Seo

2018-04-01

Full Text Available Estimation of the motion of ball-shaped objects is essential for the operation of ball sport simulators. In this paper, we propose an estimation system for 3D ball motion, including speed and angle of projection, by using acoustic vector and infrared (IR scanning sensors. Our system is comprised of three steps to estimate a ball motion: sound-based ball firing detection, sound source localization, and IR scanning for motion analysis. First, an impulsive sound classification based on the mel-frequency cepstrum and feed-forward neural network is introduced to detect the ball launch sound. An impulsive sound source localization using a 2D microelectromechanical system (MEMS microphones and delay-and-sum beamforming is presented to estimate the firing position. The time and position of a ball in 3D space is determined from a high-speed infrared scanning method. Our experimental results demonstrate that the estimation of ball motion based on sound allows a wider activity area than similar camera-based methods. Thus, it can be practically applied to various simulations in sports such as soccer and baseball.

WiFi-Based Real-Time Calibration-Free Passive Human Motion Detection

Directory of Open Access Journals (Sweden)

Liangyi Gong

2015-12-01

Full Text Available With the rapid development of WLAN technology, wireless device-free passive human detection becomes a newly-developing technique and holds more potential to worldwide and ubiquitous smart applications. Recently, indoor fine-grained device-free passive human motion detection based on the PHY layer information is rapidly developed. Previous wireless device-free passive human detection systems either rely on deploying specialized systems with dense transmitter-receiver links or elaborate off-line training process, which blocks rapid deployment and weakens system robustness. In the paper, we explore to research a novel fine-grained real-time calibration-free device-free passive human motion via physical layer information, which is independent of indoor scenarios and needs no prior-calibration and normal profile. We investigate sensitivities of amplitude and phase to human motion, and discover that phase feature is more sensitive to human motion, especially to slow human motion. Aiming at lightweight and robust device-free passive human motion detection, we develop two novel and practical schemes: short-term averaged variance ratio (SVR and long-term averaged variance ratio (LVR. We realize system design with commercial WiFi devices and evaluate it in typical multipath-rich indoor scenarios. As demonstrated in the experiments, our approach can achieve a high detection rate and low false positive rate.

WiFi-Based Real-Time Calibration-Free Passive Human Motion Detection.

Science.gov (United States)

Gong, Liangyi; Yang, Wu; Man, Dapeng; Dong, Guozhong; Yu, Miao; Lv, Jiguang

2015-12-21

With the rapid development of WLAN technology, wireless device-free passive human detection becomes a newly-developing technique and holds more potential to worldwide and ubiquitous smart applications. Recently, indoor fine-grained device-free passive human motion detection based on the PHY layer information is rapidly developed. Previous wireless device-free passive human detection systems either rely on deploying specialized systems with dense transmitter-receiver links or elaborate off-line training process, which blocks rapid deployment and weakens system robustness. In the paper, we explore to research a novel fine-grained real-time calibration-free device-free passive human motion via physical layer information, which is independent of indoor scenarios and needs no prior-calibration and normal profile. We investigate sensitivities of amplitude and phase to human motion, and discover that phase feature is more sensitive to human motion, especially to slow human motion. Aiming at lightweight and robust device-free passive human motion detection, we develop two novel and practical schemes: short-term averaged variance ratio (SVR) and long-term averaged variance ratio (LVR). We realize system design with commercial WiFi devices and evaluate it in typical multipath-rich indoor scenarios. As demonstrated in the experiments, our approach can achieve a high detection rate and low false positive rate.

Compressive Video Recovery Using Block Match Multi-Frame Motion Estimation Based on Single Pixel Cameras

Directory of Open Access Journals (Sweden)

Sheng Bi

2016-03-01

Full Text Available Compressive sensing (CS theory has opened up new paths for the development of signal processing applications. Based on this theory, a novel single pixel camera architecture has been introduced to overcome the current limitations and challenges of traditional focal plane arrays. However, video quality based on this method is limited by existing acquisition and recovery methods, and the method also suffers from being time-consuming. In this paper, a multi-frame motion estimation algorithm is proposed in CS video to enhance the video quality. The proposed algorithm uses multiple frames to implement motion estimation. Experimental results show that using multi-frame motion estimation can improve the quality of recovered videos. To further reduce the motion estimation time, a block match algorithm is used to process motion estimation. Experiments demonstrate that using the block match algorithm can reduce motion estimation time by 30%.

Angle-independent measure of motion for image-based gating in 3D coronary angiography

International Nuclear Information System (INIS)

Lehmann, Glen C.; Holdsworth, David W.; Drangova, Maria

2006-01-01

The role of three-dimensional (3D) image guidance for interventional procedures and minimally invasive surgeries is increasing for the treatment of vascular disease. Currently, most interventional procedures are guided by two-dimensional x-ray angiography, but computed rotational angiography has the potential to provide 3D geometric information about the coronary arteries. The creation of 3D angiographic images of the coronary arteries requires synchronization of data acquisition with respect to the cardiac cycle, in order to minimize motion artifacts. This can be achieved by inferring the extent of motion from a patient's electrocardiogram (ECG) signal. However, a direct measurement of motion (from the 2D angiograms) has the potential to improve the 3D angiographic images by ensuring that only projections acquired during periods of minimal motion are included in the reconstruction. This paper presents an image-based metric for measuring the extent of motion in 2D x-ray angiographic images. Adaptive histogram equalization was applied to projection images to increase the sharpness of coronary arteries and the superior-inferior component of the weighted centroid (SIC) was measured. The SIC constitutes an image-based metric that can be used to track vessel motion, independent of apparent motion induced by the rotational acquisition. To evaluate the technique, six consecutive patients scheduled for routine coronary angiography procedures were studied. We compared the end of the SIC rest period (ρ) to R-waves (R) detected in the patient's ECG and found a mean difference of 14±80 ms. Two simultaneous angular positions were acquired and ρ was detected for each position. There was no statistically significant difference (P=0.79) between ρ in the two simultaneously acquired angular positions. Thus we have shown the SIC to be independent of view angle, which is critical for rotational angiography. A preliminary image-based gating strategy that employed the SIC was

A human motion model based on maps for navigation systems

Directory of Open Access Journals (Sweden)

Kaiser Susanna

2011-01-01

Full Text Available Abstract Foot-mounted indoor positioning systems work remarkably well when using additionally the knowledge of floor-plans in the localization algorithm. Walls and other structures naturally restrict the motion of pedestrians. No pedestrian can walk through walls or jump from one floor to another when considering a building with different floor-levels. By incorporating known floor-plans in sequential Bayesian estimation processes such as particle filters (PFs, long-term error stability can be achieved as long as the map is sufficiently accurate and the environment sufficiently constraints pedestrians' motion. In this article, a new motion model based on maps and floor-plans is introduced that is capable of weighting the possible headings of the pedestrian as a function of the local environment. The motion model is derived from a diffusion algorithm that makes use of the principle of a source effusing gas and is used in the weighting step of a PF implementation. The diffusion algorithm is capable of including floor-plans as well as maps with areas of different degrees of accessibility. The motion model more effectively represents the probability density function of possible headings that are restricted by maps and floor-plans than a simple binary weighting of particles (i.e., eliminating those that crossed walls and keeping the rest. We will show that the motion model will help for obtaining better performance in critical navigation scenarios where two or more modes may be competing for some of the time (multi-modal scenarios.

On electromagnetic forming processes in finitely strained solids: Theory and examples

Science.gov (United States)

Thomas, J. D.; Triantafyllidis, N.

2009-08-01

The process of electromagnetic forming (EMF) is a high velocity manufacturing technique that uses electromagnetic (Lorentz) body forces to shape sheet metal parts. EMF holds several advantages over conventional forming techniques: speed, repeatability, one-sided tooling, and most importantly considerable ductility increase in several metals. Current modeling techniques for EMF processes are not based on coupled variational principles to simultaneously account for electromagnetic and mechanical effects. Typically, separate solutions to the electromagnetic (Maxwell) and motion (Newton) equations are combined in staggered or lock-step methods, sequentially solving the mechanical and electromagnetic problems. The present work addresses these issues by introducing a fully coupled Lagrangian (reference configuration) least-action variational principle, involving magnetic flux and electric potentials and the displacement field as independent variables. The corresponding Euler-Lagrange equations are Maxwell's and Newton's equations in the reference configuration, which are shown to coincide with their current configuration counterparts obtained independently by a direct approach. The general theory is subsequently simplified for EMF processes by considering the eddy current approximation. Next, an application is presented for axisymmetric EMF problems. It is shown that the proposed variational principle forms the basis of a variational integration numerical scheme that provides an efficient staggered solution algorithm. As an illustration a number of such processes are simulated, inspired by recent experiments of freely expanding uncoated and polyurea-coated aluminum tubes.

Numerical analysis of viscous effect on ship rolling motions based on CFD

Directory of Open Access Journals (Sweden)

LUO Tian

2017-03-01

Full Text Available During the ship design procedure, the analysis of ship rolling motions is of great significance because the rolling motions have extraordinary effects on the sea-keeping, maneuverability and stability of a ship. It is difficult to simulate rolling motions due to the effect of viscosity, which causes many nonlinear components in computation. As such, the potential theory used for other ship motions cannot be used for rolling motions. This paper simulates the rolling motions of the DTMB 5512 ship model and the ship transverse section of the S60 ship model with a naoe-FOAM-SJTU solver using the Reynolds Averaged Navier Stokes(RANSmethod based on the OpenFOAM. The results of rolling motions are compared with the experimental data, which confirms the reliability of the meshes and results. For the ship transverse section of the S60 ship model, the damping coefficient is divided into three parts with the Euler and RANS methods:friction, vorticity and wave parts. For the DTMB 5512 ship model, the damping coefficient is also respectively analyzed, including the friction, vorticity, wave and bilge keel parts. The results in this paper show that the vorticity part accounts for the greatest proportion, while the friction part accounts for the least, and the bilge keels reduces the damping moment to a certain extent which shows the effect of rolling parameters on rolling motions and moments.

Initial clinical evaluation of PET-based ion beam therapy monitoring under consideration of organ motion.

Science.gov (United States)

Kurz, Christopher; Bauer, Julia; Unholtz, Daniel; Richter, Daniel; Herfarth, Klaus; Debus, Jürgen; Parodi, Katia

2016-02-01

Intrafractional organ motion imposes considerable challenges to scanned ion beam therapy and demands for a thorough verification of the applied treatment. At the Heidelberg Ion-Beam Therapy Center (HIT), the scanned ion beam delivery is verified by means of postirradiation positron-emission-tomography (PET) imaging. This work presents a first clinical evaluation of PET-based treatment monitoring in ion beam therapy under consideration of target motion. Three patients with mobile liver lesions underwent scanned carbon ion irradiation at HIT and postirradiation PET/CT (x-ray-computed-tomography) imaging with a commercial scanner. Respiratory motion was recorded during irradiation and subsequent image acquisition. This enabled a time-resolved (4D) calculation of the expected irradiation-induced activity pattern and, for one patient where an additional 4D CT was acquired at the PET/CT scanner after treatment, a motion-compensated PET image reconstruction. For the other patients, PET data were reconstructed statically. To verify the treatment, calculated prediction and reconstructed measurement were compared with a focus on the ion beam range. Results in the current three patients suggest that for motion amplitudes in the order of 2 mm there is no benefit from incorporating respiratory motion information into PET-based treatment monitoring. For a target motion in the order of 10 mm, motion-related effects become more severe and a time-resolved modeling of the expected activity distribution can lead to an improved data interpretation if a sufficient number of true coincidences is detected. Benefits from motion-compensated PET image reconstruction could not be shown conclusively at the current stage. The feasibility of clinical PET-based treatment verification under consideration of organ motion has been shown for the first time. Improvements in noise-robust 4D PET image reconstruction are deemed necessary to enhance the clinical potential.

Initial clinical evaluation of PET-based ion beam therapy monitoring under consideration of organ motion

International Nuclear Information System (INIS)

Kurz, Christopher; Bauer, Julia; Unholtz, Daniel; Herfarth, Klaus; Debus, Jürgen; Richter, Daniel; Parodi, Katia

2016-01-01

Purpose: Intrafractional organ motion imposes considerable challenges to scanned ion beam therapy and demands for a thorough verification of the applied treatment. At the Heidelberg Ion-Beam Therapy Center (HIT), the scanned ion beam delivery is verified by means of postirradiation positron-emission-tomography (PET) imaging. This work presents a first clinical evaluation of PET-based treatment monitoring in ion beam therapy under consideration of target motion. Methods: Three patients with mobile liver lesions underwent scanned carbon ion irradiation at HIT and postirradiation PET/CT (x-ray-computed-tomography) imaging with a commercial scanner. Respiratory motion was recorded during irradiation and subsequent image acquisition. This enabled a time-resolved (4D) calculation of the expected irradiation-induced activity pattern and, for one patient where an additional 4D CT was acquired at the PET/CT scanner after treatment, a motion-compensated PET image reconstruction. For the other patients, PET data were reconstructed statically. To verify the treatment, calculated prediction and reconstructed measurement were compared with a focus on the ion beam range. Results: Results in the current three patients suggest that for motion amplitudes in the order of 2 mm there is no benefit from incorporating respiratory motion information into PET-based treatment monitoring. For a target motion in the order of 10 mm, motion-related effects become more severe and a time-resolved modeling of the expected activity distribution can lead to an improved data interpretation if a sufficient number of true coincidences is detected. Benefits from motion-compensated PET image reconstruction could not be shown conclusively at the current stage. Conclusions: The feasibility of clinical PET-based treatment verification under consideration of organ motion has been shown for the first time. Improvements in noise-robust 4D PET image reconstruction are deemed necessary to enhance the

Robust motion control of oscillatory-base manipulators h∞-control and sliding-mode-control-based approaches

CERN Document Server

Toda, Masayoshi

2016-01-01

This book provides readers with alternative robust approaches to control design for an important class of systems characteristically associated with ocean-going vessels and structures. These systems, which include crane vessels, on-board cranes, radar gimbals, and a conductivity temperature and depth winch, are modelled as manipulators with oscillating bases. One design approach is based on the H-infinity control framework exploiting an effective combination of PD control, an extended matrix polytope and a robust stability analysis method with a state-dependent coefficient form. The other is based on sliding-mode control using some novel nonlinear sliding surfaces. The model demonstrates how successful motion control can be achieved by suppressing base oscillations and in the presence of uncertainties. This is important not only for ocean engineering systems in which the problems addressed here originate but more generally as a benchmark platform for robust motion control with disturbance rejection. Researche...

Reflections on Students’ Projects with Motion Sensor Technologies in a Problem-Based Learning Environment

DEFF Research Database (Denmark)

Triantafyllou, Eva; Timcenko, Olga; Triantafyllidis, George

2014-01-01

Game-based learning (GBL) has been applied in many fields to enhance learning motivations. In recent years, motion sensor technologies have been also introduced in GBL with the aim of using active, physical modalities to facilitate the learning process, while fostering social development...... and collaboration (when these activities involve more than one student at a time). The approaches described in literature, which used motion sensors in GBL, cover a broad spectrum of educational fields. These approaches investigated the effect of learning games using motion sensors on the development of specific...... skills or on the learning experience. This paper presents our experiences on the educational use of motion sensor technologies. Our research was conducted at the department of Medialogy in Aalborg University Copenhagen. Aalborg University applies a problem-based, project-organized model of teaching...

A respiratory monitoring device based on clavicular motion

International Nuclear Information System (INIS)

Pitts, D G; Aspinall, R; Patel, M K; Lang, P-O; Sinclair, A J

2013-01-01

Respiratory rate is one of the key vital signs yet unlike temperature, heart rate or blood pressure, there is no simple and low cost measurement device for medical use. Here we discuss the development of a respiratory sensor based upon clavicular motion and the findings of a pilot study comparing respiratory rate readings derived from clavicular and thoracic motion with an expiratory breath flow reference sensor. Simultaneously sampled data from resting volunteers (n = 8) was analysed to determine the location of individual breaths in the data set and from these, breath periods and frequency were calculated. Clavicular sensor waveforms were found to be more consistent and of greater amplitude than those from the thoracic device, demonstrating good alignment with the reference waveform. On comparing breath by breath periods a close agreement was observed with the reference, with mean clavicular respiratory rate R 2 values of 0.89 (lateral) and 0.98 (longitudinal-axis). This pilot study demonstrates the viability of clavicular respiratory sensing. The sensor is unobtrusive, unaffected by bioelectrical or electrode problems and easier to determine and more consistent than thoracic motion sensing. With relatively basic signal conditioning and processing requirements, it could provide an ideal platform for a low-cost respiratory monitor. (note)

Dynamic vision based on motion-contrast: changes with age in adults.

Science.gov (United States)

Wist, E R; Schrauf, M; Ehrenstein, W H

2000-10-01

Data are presented for a computerized test of dynamic vision in a sample of 1006 healthy subjects aged between 20 and 85 years. The test employed a form-from-motion stimulus: i.e., within a random-dot display, Landolt rings of the same average luminance as their surroundings become visible only when the dots within the ring are moved briefly, while those of the surround remain stationary. Thus, detection of gap location is based upon motion contrast (form-from-motion) rather than luminance contrast. With the size and exposure duration of the centrally presented ring held constant, motion contrast was manipulated by varying the percentage (between 20 and 100%) of moving dots within the ring. Subjects reported gap location (left, right, top, bottom). A gradual decline of dynamic vision with age was found for all motion-contrast levels. Beyond 70 years of age, chance-level performance occurred in almost half of the subjects. The data provide the basis for applications including diagnostic screening for glaucoma, visual disturbances in brain-damaged patients, as well as assessment of the dynamic vision of drivers of motor vehicles and athletes.

Real-time tumor motion estimation using respiratory surrogate via memory-based learning

International Nuclear Information System (INIS)

Li Ruijiang; Xing Lei; Lewis, John H; Berbeco, Ross I

2012-01-01

Respiratory tumor motion is a major challenge in radiation therapy for thoracic and abdominal cancers. Effective motion management requires an accurate knowledge of the real-time tumor motion. External respiration monitoring devices (optical, etc) provide a noninvasive, non-ionizing, low-cost and practical approach to obtain the respiratory signal. Due to the highly complex and nonlinear relations between tumor and surrogate motion, its ultimate success hinges on the ability to accurately infer the tumor motion from respiratory surrogates. Given their widespread use in the clinic, such a method is critically needed. We propose to use a powerful memory-based learning method to find the complex relations between tumor motion and respiratory surrogates. The method first stores the training data in memory and then finds relevant data to answer a particular query. Nearby data points are assigned high relevance (or weights) and conversely distant data are assigned low relevance. By fitting relatively simple models to local patches instead of fitting one single global model, it is able to capture highly nonlinear and complex relations between the internal tumor motion and external surrogates accurately. Due to the local nature of weighting functions, the method is inherently robust to outliers in the training data. Moreover, both training and adapting to new data are performed almost instantaneously with memory-based learning, making it suitable for dynamically following variable internal/external relations. We evaluated the method using respiratory motion data from 11 patients. The data set consists of simultaneous measurement of 3D tumor motion and 1D abdominal surface (used as the surrogate signal in this study). There are a total of 171 respiratory traces, with an average peak-to-peak amplitude of ∼15 mm and average duration of ∼115 s per trace. Given only 5 s (roughly one breath) pretreatment training data, the method achieved an average 3D error of 1.5 mm and 95

Real-time tumor motion estimation using respiratory surrogate via memory-based learning

Science.gov (United States)

Li, Ruijiang; Lewis, John H.; Berbeco, Ross I.; Xing, Lei

2012-08-01

Respiratory tumor motion is a major challenge in radiation therapy for thoracic and abdominal cancers. Effective motion management requires an accurate knowledge of the real-time tumor motion. External respiration monitoring devices (optical, etc) provide a noninvasive, non-ionizing, low-cost and practical approach to obtain the respiratory signal. Due to the highly complex and nonlinear relations between tumor and surrogate motion, its ultimate success hinges on the ability to accurately infer the tumor motion from respiratory surrogates. Given their widespread use in the clinic, such a method is critically needed. We propose to use a powerful memory-based learning method to find the complex relations between tumor motion and respiratory surrogates. The method first stores the training data in memory and then finds relevant data to answer a particular query. Nearby data points are assigned high relevance (or weights) and conversely distant data are assigned low relevance. By fitting relatively simple models to local patches instead of fitting one single global model, it is able to capture highly nonlinear and complex relations between the internal tumor motion and external surrogates accurately. Due to the local nature of weighting functions, the method is inherently robust to outliers in the training data. Moreover, both training and adapting to new data are performed almost instantaneously with memory-based learning, making it suitable for dynamically following variable internal/external relations. We evaluated the method using respiratory motion data from 11 patients. The data set consists of simultaneous measurement of 3D tumor motion and 1D abdominal surface (used as the surrogate signal in this study). There are a total of 171 respiratory traces, with an average peak-to-peak amplitude of ∼15 mm and average duration of ∼115 s per trace. Given only 5 s (roughly one breath) pretreatment training data, the method achieved an average 3D error of 1.5 mm and 95

Structural motion engineering

CERN Document Server

Connor, Jerome

2014-01-01

This innovative volume provides a systematic treatment of the basic concepts and computational procedures for structural motion design and engineering for civil installations. The authors illustrate the application of motion control to a wide spectrum of buildings through many examples. Topics covered include optimal stiffness distributions for building-type structures, the role of damping in controlling motion, tuned mass dampers, base isolation systems, linear control, and nonlinear control. The book's primary objective is the satisfaction of motion-related design requirements, such as restrictions on displacement and acceleration. The book is ideal for practicing engineers and graduate students. This book also: ·         Broadens practitioners' understanding of structural motion control, the enabling technology for motion-based design ·         Provides readers the tools to satisfy requirements of modern, ultra-high strength materials that lack corresponding stiffness, where the motion re...

Radiotherapy of tumors under respiratory motion. Estimation of the motional velocity field and dose accumulation based on 4D image data

International Nuclear Information System (INIS)

Werner, Rene

2013-01-01

belong to the most precise methods currently available. In clinical practice, however, there exists the problem that many medical facilities are not equipped with 4D imaging devices. Further, 4D images still offer only a snapshot of the patient-specific motion range and potential motion variability may limit the conclusions that can be drawn from them. To address these aspects, in the next part of the thesis - based on the optimized methods for motion field estimation in 4D CT image data and further including statistical motion information and models, respectively - model-based approaches for motion field estimation and prediction are developed. First, a novel approach for statistical modeling of lung motion in a patient collective is presented, and methods for adapting the model for prediction of patient-specific motion patterns are provided. The latter allow, for instance, the estimation of respiratory lung and lung tumor motion for radiation therapy treatment planning, if no temporally resolved image sequences are available for the patient; this use case is demonstrated. Further, techniques of multivariate statistics are applied to account for variations of motion patterns by integrating additional information provided by motion indicators used in 4D radiation therapy (e.g. abdominal belts or spirometer measurements) for a patient-specific, situation-related adaption of the motion fields computed using 4D images and the methods for motion field estimation described before. In the last part of the thesis, the developed methods are finally applied for assessing and analyzing the dosimetric impact of respiratory motion during radiation therapy of lung tumors. Both 3D conformal radiotherapy and intensity modulated radiotherapy are modeled as treatment modalities. In the case of intensity modulated radiotherapy, short delivery times for single radiation fields lead to the risk that the corresponding dose contributions are not only subject to a motion-induced dose blurring

SU-E-J-181: Effect of Prostate Motion On Combined Brachytherapy and External Beam Dose Based On Daily Motion of the Prostate

Energy Technology Data Exchange (ETDEWEB)

Narayana, V; McLaughlin, P [Providence Cancer Center, Southfield, MI (United States); University of Michigan, Ann Arbor, MI (United States); Ealbaj, J [University of Michigan, Ann Arbor, MI (United States)

2015-06-15

Purpose: In this study, the adequacy of target expansions on the combined external beam and implant dose was examined based on the measured daily motion of the prostate. Methods: Thirty patients received an I–125 prostate implant prescribed to dose of 90Gy. This was followed by external beam to deliver a dose of 90Gyeq (external beam equivalent) to the prostate over 25 to 30 fractions. An ideal IMRT plan was developed by optimizing the external beam dose based on the delivered implant dose. The implant dose was converted to an equivalent external beam dose using the linear quadratic model. Patients were set up on the treatment table by daily orthogonal imaging and aligning the marker seeds in the prostate. Orthogonal images were obtained at the end of treatment to assess prostate intrafraction motion. Based on the observed motion of the markers between the initial and final images, 5 individual plans showing the actual dose delivered to the patient were calculated. A final true dose distribution was established based on summing the implant dose and the 5 external beam plans. Dose to the prostate, seminal vesicles, lymphnodes and normal tissues, rectal wall, urethra and lower sphincter were calculated and compared to ideal. On 18 patients who were sexually active, dose to the corpus cavernosum and internal pudendal artery was also calculated. Results: The average prostate motion in 3 orthogonal directions was less than 1 mm with a standard deviation of less than +2 mm. Dose and volume parameters showed that there was no decrease in dose to the targets and a marginal decrease in dose to in normal tissues. Conclusion: Dose delivered by seed implant moves with the prostate, decreasing the impact of intrafractions dose movement on actual dose delivered. Combined brachytherapy and external beam dose delivered to the prostate was not sensitive to prostate motion.

On the Application of TLS Techniques to AC Electrical Drives

Directory of Open Access Journals (Sweden)

M. Cirrincione

2005-03-01

Full Text Available This paper deals with the application of a new neuron, the TLS EXIN neuron, to AC induction motor drives. In particular, it addresses two important subjects of AC induction motor drives: the on-line estimation of the electrical parameters of the machine and the speed estimation in sensorless drives. On this basis, this work summarizes the parameter estimation and sensorless techniques already developed by the authors over these last few years, all based on the TLS EXIN. With regard to sensorless, two techniques are proposed: one based on the MRAS and the other based on the full-order Luenberger observer. The work show some of the most significant results obtained by the authors in these fields and stresses the important potentiality of this new neural technique in AC induction machine drives.

Bounds on the vibrational energy that can be harvested from random base motion

Science.gov (United States)

Langley, R. S.

2015-03-01

This paper is concerned with the development of upper bounds on the energy harvesting performance of a general multi-degree-of-freedom nonlinear electromechanical system that is subjected to random base motion and secondary applied periodic forces. The secondary forces are applied with the aim of enhancing the energy harvested from the base motion, and they may constitute direct excitation, or they may produce parametric terms in the equations of motion. It is shown that when the base motion has white noise acceleration then the power input by the base is always πS0 M / 2 where S0 is the single sided spectral density of the acceleration, and M is the mass of the system. This implies that although the secondary forces may enhance the energy harvested by causing a larger fraction of the power input from the base to be harvested rather than dissipated, there is an upper limit on the power that can be harvested. Attention is then turned to narrow band excitation, and it is found that in the absence of secondary forces a bound can be derived for a single degree of freedom system with linear damping and arbitrary nonlinear stiffness. The upper bound on the power input by the base is πM max [ S (ω) ] / 2, where S (ω) is the single sided base acceleration spectrum. The validity of this result for more general systems is found to be related to the properties of the first Wiener kernel, and this issue is explored analytically and by numerical simulation.

User-based motion sensing and fuzzy logic for automated fall detection in older adults

DEFF Research Database (Denmark)

Boissy, Patrice; Choquette, Stéphane; Hamel, Mathieu

2007-01-01

, and reduce complications from falls. The performance of a 2-stage fall detection algorithm using impact magnitudes and changes in trunk angles derived from user-based motion sensors was evaluated under laboratory conditions. Ten healthy participants were instrumented on the front and side of the trunk with 3...... fall conditions with a success rate of 93% and a false-positive rate of 29% during nonfall conditions. Despite a slightly superior identification performance for the accelerometer located on the front of the trunk, no significant differences were found between the two motion sensor locations. Automated...... detection of fall events based on user-based motion sensing and fuzzy logic shows promising results. Additional rules and optimization of the algorithm will be needed to decrease the false-positive rate....

Fusion of optical flow based motion pattern analysis and silhouette classification for person tracking and detection

NARCIS (Netherlands)

Tangelder, J.W.H.; Lebert, E.; Burghouts, G.J.; Zon, K. van; Den Uyl, M.J.

2014-01-01

This paper presents a novel approach to detect persons in video by combining optical flow based motion analysis and silhouette based recognition. A new fast optical flow computation method is described, and its application in a motion based analysis framework unifying human tracking and detection is

Response of base isolated structure during strong ground motions beyond design earthquakes

International Nuclear Information System (INIS)

Yabana, Shuichi; Ishida, Katsuhiko; Shiojiri, Hiroo

1991-01-01

In Japan, some base isolated structures for fast breeder reactors (FBR) are tried to design. When a base isolated structure are designed, the relative displacement of isolators are generally limited so sa to be remain in linear state of those during design earthquakes. But to estimate safety margin of a base isolated structure, the response of that until the failure must be obtained experimentally to analytically during strong ground motions of beyond design earthquake. The aim of this paper is to investigate the response of a base isolated structure when the stiffness of the isolators hardens and to simulate the response during strong ground motions of beyond design earthquakes. The optimum characteristics of isolators, with which the margin of the structure are increased, are discussed. (author)

Engineering Seismic Base Layer for Defining Design Earthquake Motion

International Nuclear Information System (INIS)

Yoshida, Nozomu

2008-01-01

Engineer's common sense that incident wave is common in a widespread area at the engineering seismic base layer is shown not to be correct. An exhibiting example is first shown, which indicates that earthquake motion at the ground surface evaluated by the analysis considering the ground from a seismic bedrock to a ground surface simultaneously (continuous analysis) is different from the one by the analysis in which the ground is separated at the engineering seismic base layer and analyzed separately (separate analysis). The reason is investigated by several approaches. Investigation based on eigen value problem indicates that the first predominant period in the continuous analysis cannot be found in the separate analysis, and predominant period at higher order does not match in the upper and lower ground in the separate analysis. The earthquake response analysis indicates that reflected wave at the engineering seismic base layer is not zero, which indicates that conventional engineering seismic base layer does not work as expected by the term ''base''. All these results indicate that wave that goes down to the deep depths after reflecting in the surface layer and again reflects at the seismic bedrock cannot be neglected in evaluating the response at the ground surface. In other words, interaction between the surface layer and/or layers between seismic bedrock and engineering seismic base layer cannot be neglected in evaluating the earthquake motion at the ground surface

Experimental investigation of irregular motion impact on 4D PET-based particle therapy monitoring

International Nuclear Information System (INIS)

Tian, Y; Stützer, K; Enghardt, W; Priegnitz, M; Helmbrecht, S; Fiedler, F; Bert, C

2016-01-01

Particle therapy positron emission tomography (PT-PET) is an in vivo and non-invasive imaging technique to monitor treatment delivery in particle therapy. The inevitable patient respiratory motion during irradiation causes artefacts and inaccurate activity distribution in PET images. Four-dimensional (4D) maximum likelihood expectation maximisation (4D MLEM) allows for a compensation of these effects, but has up to now been restricted to regular motion for PT-PET investigations. However, intra-fractional motion during treatment might differ from that during acquisition of the 4D-planning CT (e.g. amplitude variation, baseline drift) and therefore might induce inaccurate 4D PET reconstruction results. This study investigates the impact of different irregular analytical one-dimensional (1D) motion patterns on PT-PET imaging by means of experiments with a radioactive source and irradiated moving phantoms. Three sorting methods, namely phase sorting, equal amplitude sorting and event-based amplitude sorting, were applied to manage the PET list-mode data. The influence of these sorting methods on the motion compensating algorithm has been analysed. The event-based amplitude sorting showed a superior performance and it is applicable for irregular motions with  ⩽4 mm amplitude elongation and drift. For motion with 10 mm baseline drift, the normalised root mean square error was as high as 10.5% and a 10 mm range deviation was observed. (note)

Experimental investigation of irregular motion impact on 4D PET-based particle therapy monitoring

Science.gov (United States)

Tian, Y.; Stützer, K.; Enghardt, W.; Priegnitz, M.; Helmbrecht, S.; Bert, C.; Fiedler, F.

2016-01-01

Particle therapy positron emission tomography (PT-PET) is an in vivo and non-invasive imaging technique to monitor treatment delivery in particle therapy. The inevitable patient respiratory motion during irradiation causes artefacts and inaccurate activity distribution in PET images. Four-dimensional (4D) maximum likelihood expectation maximisation (4D MLEM) allows for a compensation of these effects, but has up to now been restricted to regular motion for PT-PET investigations. However, intra-fractional motion during treatment might differ from that during acquisition of the 4D-planning CT (e.g. amplitude variation, baseline drift) and therefore might induce inaccurate 4D PET reconstruction results. This study investigates the impact of different irregular analytical one-dimensional (1D) motion patterns on PT-PET imaging by means of experiments with a radioactive source and irradiated moving phantoms. Three sorting methods, namely phase sorting, equal amplitude sorting and event-based amplitude sorting, were applied to manage the PET list-mode data. The influence of these sorting methods on the motion compensating algorithm has been analysed. The event-based amplitude sorting showed a superior performance and it is applicable for irregular motions with  ⩽4 mm amplitude elongation and drift. For motion with 10 mm baseline drift, the normalised root mean square error was as high as 10.5% and a 10 mm range deviation was observed.

MotionFlow: Visual Abstraction and Aggregation of Sequential Patterns in Human Motion Tracking Data.

Science.gov (United States)

Jang, Sujin; Elmqvist, Niklas; Ramani, Karthik

2016-01-01

Pattern analysis of human motions, which is useful in many research areas, requires understanding and comparison of different styles of motion patterns. However, working with human motion tracking data to support such analysis poses great challenges. In this paper, we propose MotionFlow, a visual analytics system that provides an effective overview of various motion patterns based on an interactive flow visualization. This visualization formulates a motion sequence as transitions between static poses, and aggregates these sequences into a tree diagram to construct a set of motion patterns. The system also allows the users to directly reflect the context of data and their perception of pose similarities in generating representative pose states. We provide local and global controls over the partition-based clustering process. To support the users in organizing unstructured motion data into pattern groups, we designed a set of interactions that enables searching for similar motion sequences from the data, detailed exploration of data subsets, and creating and modifying the group of motion patterns. To evaluate the usability of MotionFlow, we conducted a user study with six researchers with expertise in gesture-based interaction design. They used MotionFlow to explore and organize unstructured motion tracking data. Results show that the researchers were able to easily learn how to use MotionFlow, and the system effectively supported their pattern analysis activities, including leveraging their perception and domain knowledge.

Entropy-Based Video Steganalysis of Motion Vectors

Directory of Open Access Journals (Sweden)

Elaheh Sadat Sadat

2018-04-01

Full Text Available In this paper, a new method is proposed for motion vector steganalysis using the entropy value and its combination with the features of the optimized motion vector. In this method, the entropy of blocks is calculated to determine their texture and the precision of their motion vectors. Then, by using a fuzzy cluster, the blocks are clustered into the blocks with high and low texture, while the membership function of each block to a high texture class indicates the texture of that block. These membership functions are used to weight the effective features that are extracted by reconstructing the motion estimation equations. Characteristics of the results indicate that the use of entropy and the irregularity of each block increases the precision of the final video classification into cover and stego classes.

Modification of hemiplegic compensatory gait pattern by symmetry-based motion controller of HAL.

Science.gov (United States)

Kawamoto, Hiroaki; Kadone, Hideki; Sakurai, Takeru; Sankai, Yoshiyuki

2015-01-01

As one of several characteristics of hemiplegic patients after stroke, compensatory gait caused by affected limb is often seen. The purpose of this research is to apply a symmetry-based controller of a wearable type lower limb robot, Hybrid Assistive Limb (HAL) to hemiplegic patients with compensatory gait, and to investigate improvement of gait symmetry. The controller is designed respectively for swing phase and support phase according to characteristics of hemiplegic gait pattern. The controller during swing phase stores the motion of the unaffected limb and then provides motion support on the affected limb during the subsequent swing using the stored pattern to realize symmetric gait based on spontaneous limb swing. Moreover, the controller during support phase provides motion to extend hip and knee joints to support wearer's body. Clinical tests were conducted in order to assess the modification of gait symmetry. Our case study involved participation of one chronic stroke patient who performs abnormally-compensatory gait for both of the affected and unaffected limbs. As a result, the patient's gait symmetry was improved by providing motion support during the swing phase on the affected side and motion constraint during the support phase on the unaffected side. The study showed promising basis for the effectiveness of the controller for the future clinical study.

Content and structure of knowledge base used for virtual control of android arm motion in specified environment

Science.gov (United States)

Pritykin, F. N.; Nebritov, V. I.

2018-01-01

The paper presents the configuration of knowledge base necessary for intelligent control of android arm mechanism motion with different positions of certain forbidden regions taken into account. The present structure of the knowledge base characterizes the past experience of arm motion synthesis in the vector of velocities with due regard for the known obstacles. This structure also specifies its intrinsic properties. Knowledge base generation is based on the study of the arm mechanism instantaneous states implementations. Computational experiments connected with the virtual control of android arm motion with known forbidden regions using the developed knowledge base are introduced. Using the developed knowledge base to control virtually the arm motion reduces the time of test assignments calculation. The results of the research can be used in developing control systems of autonomous android robots in the known in advance environment.

Comparison of two Simon tasks: neuronal correlates of conflict resolution based on coherent motion perception.

Science.gov (United States)

Wittfoth, Matthias; Buck, Daniela; Fahle, Manfred; Herrmann, Manfred

2006-08-15

The present study aimed at characterizing the neural correlates of conflict resolution in two variations of the Simon effect. We introduced two different Simon tasks where subjects had to identify shapes on the basis of form-from-motion perception (FFMo) within a randomly moving dot field, while (1) motion direction (motion-based Simon task) or (2) stimulus location (location-based Simon task) had to be ignored. Behavioral data revealed that both types of Simon tasks induced highly significant interference effects. Using event-related fMRI, we could demonstrate that both tasks share a common cluster of activated brain regions during conflict resolution (pre-supplementary motor area (pre-SMA), superior parietal lobule (SPL), and cuneus) but also show task-specific activation patterns (left superior temporal cortex in the motion-based, and the left fusiform gyrus in the location-based Simon task). Although motion-based and location-based Simon tasks are conceptually very similar (Type 3 stimulus-response ensembles according to the taxonomy of [Kornblum, S., Stevens, G. (2002). Sequential effects of dimensional overlap: findings and issues. In: Prinz, W., Hommel., B. (Eds.), Common mechanism in perception and action. Oxford University Press, Oxford, pp. 9-54]) conflict resolution in both tasks results in the activation of different task-specific regions probably related to the different sources of task-irrelevant information. Furthermore, the present data give evidence those task-specific regions are most likely to detect the relationship between task-relevant and task-irrelevant information.

Real-time prediction of respiratory motion based on local regression methods

International Nuclear Information System (INIS)

Ruan, D; Fessler, J A; Balter, J M

2007-01-01

Recent developments in modulation techniques enable conformal delivery of radiation doses to small, localized target volumes. One of the challenges in using these techniques is real-time tracking and predicting target motion, which is necessary to accommodate system latencies. For image-guided-radiotherapy systems, it is also desirable to minimize sampling rates to reduce imaging dose. This study focuses on predicting respiratory motion, which can significantly affect lung tumours. Predicting respiratory motion in real-time is challenging, due to the complexity of breathing patterns and the many sources of variability. We propose a prediction method based on local regression. There are three major ingredients of this approach: (1) forming an augmented state space to capture system dynamics, (2) local regression in the augmented space to train the predictor from previous observation data using semi-periodicity of respiratory motion, (3) local weighting adjustment to incorporate fading temporal correlations. To evaluate prediction accuracy, we computed the root mean square error between predicted tumor motion and its observed location for ten patients. For comparison, we also investigated commonly used predictive methods, namely linear prediction, neural networks and Kalman filtering to the same data. The proposed method reduced the prediction error for all imaging rates and latency lengths, particularly for long prediction lengths

Multi-story base-isolated buildings under a harmonic ground motion. Pt. 1

International Nuclear Information System (INIS)

Fan Fagung; Ahmadi, G.; Tadjbakhsh, I.G.

1990-01-01

The performances of several leading base-isolation devices (Pure-Friction/Sliding-Joint, Rubber Bearing, French System, New Zealand System, and Resilient-Friction) and a newly proposed system (Sliding Resilient-Friction) for a multi-story building subject to a horizontal harmonic ground motion are studied. The governing equations of motion of various systems and the criteria for stick-slip transition are described and a computational algorithm for obtaining their numerical solutions is developed. The responses of the structure with different base-isolation systems under various conditions are analyzed. The peak absolute acceleration, the maximum structural deflection, and the peak base-displacement responses are obtained. The effectiveness of various base isolators are studied and advantages and disadvantages of different systems are discussed. The results show that the base-isolation devices effectively reduce the column stresses and the acceleration transmitted to the superstructure. (orig.)

Frame based Motion Detection for real-time Surveillance

OpenAIRE

Brajesh Patel; Neelam Patel

2012-01-01

In this paper a series of algorithm has been formed to track the feature of motion detection under surveillance system. In the proposed work a pixel variant plays a vital role in detection of moving object of a particular clip. If there is a little bit motion in a frame then it is detected very easily by calculating pixel variance. This algorithm detects the zero variation only when there is no motion in a real-time video sequence. It is simple and easier for motion detection in the fames of ...

Two Simon tasks with different sources of conflict: an ERP study of motion- and location-based compatibility effects.

Science.gov (United States)

Galashan, Daniela; Wittfoth, Matthias; Fehr, Thorsten; Herrmann, Manfred

2008-07-01

Behavioral and electrophysiological correlates of two Simon tasks were examined using comparable stimuli but different task-irrelevant and conflict-inducing stimulus features. Whereas target shape was always the task-relevant stimulus attribute, either target location (location-based task) or motion direction within the target stimuli (motion-based task) was used as a source of conflict. Data from ten healthy participants who performed both tasks are presented. In the motion-based task the incompatible condition showed smaller P300 amplitudes at Pz than the compatible condition and the location-based task yielded a trend towards a reduced P300 amplitude in the incompatible condition. For both tasks, no P300 latency differences between the conditions were found at Pz. The results suggest that the motion-based task elicits behavioral and electrophysiological effects comparable with regular Simon tasks. As all stimuli in the motion-based Simon task were presented centrally the present data strongly argue against the attention-shifting account as an explanatory approach.

WiFi-Based Real-Time Calibration-Free Passive Human Motion Detection †

Science.gov (United States)

Gong, Liangyi; Yang, Wu; Man, Dapeng; Dong, Guozhong; Yu, Miao; Lv, Jiguang

2015-01-01

With the rapid development of WLAN technology, wireless device-free passive human detection becomes a newly-developing technique and holds more potential to worldwide and ubiquitous smart applications. Recently, indoor fine-grained device-free passive human motion detection based on the PHY layer information is rapidly developed. Previous wireless device-free passive human detection systems either rely on deploying specialized systems with dense transmitter-receiver links or elaborate off-line training process, which blocks rapid deployment and weakens system robustness. In the paper, we explore to research a novel fine-grained real-time calibration-free device-free passive human motion via physical layer information, which is independent of indoor scenarios and needs no prior-calibration and normal profile. We investigate sensitivities of amplitude and phase to human motion, and discover that phase feature is more sensitive to human motion, especially to slow human motion. Aiming at lightweight and robust device-free passive human motion detection, we develop two novel and practical schemes: short-term averaged variance ratio (SVR) and long-term averaged variance ratio (LVR). We realize system design with commercial WiFi devices and evaluate it in typical multipath-rich indoor scenarios. As demonstrated in the experiments, our approach can achieve a high detection rate and low false positive rate. PMID:26703612

A research on motion design for APP's loading pages based on time perception

Science.gov (United States)

Cao, Huai; Hu, Xiaoyun

2018-04-01

Due to restrictions caused by objective reasons like network bandwidth, hardware performance and etc., waiting is still an inevitable phenomenon that appears in our using mobile-terminal products. Relevant researches show that users' feelings in a waiting scenario can affect their evaluations on the whole product and services the product provides. With the development of user experience and inter-facial design subjects, the role of motion effect in the interface design has attracted more and more scholars' attention. In the current studies, the research theory of motion design in a waiting scenario is imperfect. This article will use the basic theory and experimental research methods of cognitive psychology to explore the motion design's impact on user's time perception when users are waiting for loading APP pages. Firstly, the article analyzes the factors that affect waiting experience of loading APP pages based on the theory of time perception, and then discusses motion design's impact on the level of time-perception when loading pages and its design strategy. Moreover, by the operation analysis of existing loading motion designs, the article classifies the existing loading motions and designs an experiment to verify the impact of different types of motions on the user's time perception. The result shows that the waiting time perception of mobile's terminals' APPs is related to the loading motion types, the combination type of loading motions can effectively shorten the waiting time perception as it scores a higher mean value in the length of time perception.

Magnetic Resonance Imaging–Guided versus Surrogate-Based Motion Tracking in Liver Radiation Therapy: A Prospective Comparative Study

Energy Technology Data Exchange (ETDEWEB)

Paganelli, Chiara, E-mail: chiara.paganelli@polimi.it [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Seregni, Matteo; Fattori, Giovanni [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Summers, Paul [Division of Radiology, Istituto Europeo di Oncologia, Milano (Italy); Bellomi, Massimo [Division of Radiology, Istituto Europeo di Oncologia, Milano (Italy); Department of Health Sciences, Università degli Studi di Milano, Milano (Italy); Baroni, Guido; Riboldi, Marco [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit, CNAO Foundation, Pavia (Italy)

2015-03-15

Purpose: This study applied automatic feature detection on cine–magnetic resonance imaging (MRI) liver images in order to provide a prospective comparison between MRI-guided and surrogate-based tracking methods for motion-compensated liver radiation therapy. Methods and Materials: In a population of 30 subjects (5 volunteers plus 25 patients), 2 oblique sagittal slices were acquired across the liver at high temporal resolution. An algorithm based on scale invariant feature transform (SIFT) was used to extract and track multiple features throughout the image sequence. The position of abdominal markers was also measured directly from the image series, and the internal motion of each feature was quantified through multiparametric analysis. Surrogate-based tumor tracking with a state-of-the-art external/internal correlation model was simulated. The geometrical tracking error was measured, and its correlation with external motion parameters was also investigated. Finally, the potential gain in tracking accuracy relying on MRI guidance was quantified as a function of the maximum allowed tracking error. Results: An average of 45 features was extracted for each subject across the whole liver. The multi-parametric motion analysis reported relevant inter- and intrasubject variability, highlighting the value of patient-specific and spatially-distributed measurements. Surrogate-based tracking errors (relative to the motion amplitude) were were in the range 7% to 23% (1.02-3.57mm) and were significantly influenced by external motion parameters. The gain of MRI guidance compared to surrogate-based motion tracking was larger than 30% in 50% of the subjects when considering a 1.5-mm tracking error tolerance. Conclusions: Automatic feature detection applied to cine-MRI allows detailed liver motion description to be obtained. Such information was used to quantify the performance of surrogate-based tracking methods and to provide a prospective comparison with respect to MRI

List-mode-based reconstruction for respiratory motion correction in PET using non-rigid body transformations

International Nuclear Information System (INIS)

Lamare, F; Carbayo, M J Ledesma; Cresson, T; Kontaxakis, G; Santos, A; Rest, C Cheze Le; Reader, A J; Visvikis, D

2007-01-01

Respiratory motion in emission tomography leads to reduced image quality. Developed correction methodology has been concentrating on the use of respiratory synchronized acquisitions leading to gated frames. Such frames, however, are of low signal-to-noise ratio as a result of containing reduced statistics. In this work, we describe the implementation of an elastic transformation within a list-mode-based reconstruction for the correction of respiratory motion over the thorax, allowing the use of all data available throughout a respiratory motion average acquisition. The developed algorithm was evaluated using datasets of the NCAT phantom generated at different points throughout the respiratory cycle. List-mode-data-based PET-simulated frames were subsequently produced by combining the NCAT datasets with Monte Carlo simulation. A non-rigid registration algorithm based on B-spline basis functions was employed to derive transformation parameters accounting for the respiratory motion using the NCAT dynamic CT images. The displacement matrices derived were subsequently applied during the image reconstruction of the original emission list mode data. Two different implementations for the incorporation of the elastic transformations within the one-pass list mode EM (OPL-EM) algorithm were developed and evaluated. The corrected images were compared with those produced using an affine transformation of list mode data prior to reconstruction, as well as with uncorrected respiratory motion average images. Results demonstrate that although both correction techniques considered lead to significant improvements in accounting for respiratory motion artefacts in the lung fields, the elastic-transformation-based correction leads to a more uniform improvement across the lungs for different lesion sizes and locations

Nonlinear Model Predictive Control of a Cable-Robot-Based Motion Simulator

DEFF Research Database (Denmark)

Katliar, Mikhail; Fischer, Joerg; Frison, Gianluca

2017-01-01

In this paper we present the implementation of a model-predictive controller (MPC) for real-time control of a cable-robot-based motion simulator. The controller computes control inputs such that a desired acceleration and angular velocity at a defined point in simulator's cabin are tracked while...... satisfying constraints imposed by working space and allowed cable forces of the robot. In order to fully use the simulator capabilities, we propose an approach that includes the motion platform actuation in the MPC model. The tracking performance and computation time of the algorithm are investigated...

Motion Transplantation Techniques: A Survey

NARCIS (Netherlands)

van Basten, Ben; Egges, Arjan

2012-01-01

During the past decade, researchers have developed several techniques for transplanting motions. These techniques transplant a partial auxiliary motion, possibly defined for a small set of degrees of freedom, on a base motion. Motion transplantation improves motion databases' expressiveness and

Patch-based frame interpolation for old films via the guidance of motion paths

Science.gov (United States)

Xia, Tianran; Ding, Youdong; Yu, Bing; Huang, Xi

2018-04-01

Due to improper preservation, traditional films will appear frame loss after digital. To deal with this problem, this paper presents a new adaptive patch-based method of frame interpolation via the guidance of motion paths. Our method is divided into three steps. Firstly, we compute motion paths between two reference frames using optical flow estimation. Then, the adaptive bidirectional interpolation with holes filled is applied to generate pre-intermediate frames. Finally, using patch match to interpolate intermediate frames with the most similar patches. Since the patch match is based on the pre-intermediate frames that contain the motion paths constraint, we show a natural and inartificial frame interpolation. We test different types of old film sequences and compare with other methods, the results prove that our method has a desired performance without hole or ghost effects.

The lucky image-motion prediction for simple scene observation based soft-sensor technology

Science.gov (United States)

Li, Yan; Su, Yun; Hu, Bin

2015-08-01

High resolution is important to earth remote sensors, while the vibration of the platforms of the remote sensors is a major factor restricting high resolution imaging. The image-motion prediction and real-time compensation are key technologies to solve this problem. For the reason that the traditional autocorrelation image algorithm cannot meet the demand for the simple scene image stabilization, this paper proposes to utilize soft-sensor technology in image-motion prediction, and focus on the research of algorithm optimization in imaging image-motion prediction. Simulations results indicate that the improving lucky image-motion stabilization algorithm combining the Back Propagation Network (BP NN) and support vector machine (SVM) is the most suitable for the simple scene image stabilization. The relative error of the image-motion prediction based the soft-sensor technology is below 5%, the training computing speed of the mathematical predication model is as fast as the real-time image stabilization in aerial photography.

A High-precision Motion Compensation Method for SAR Based on Image Intensity Optimization

Directory of Open Access Journals (Sweden)

Hu Ke-bin

2015-02-01

Full Text Available Owing to the platform instability and precision limitations of motion sensors, motion errors negatively affect the quality of synthetic aperture radar (SAR images. The autofocus Back Projection (BP algorithm based on the optimization of image sharpness compensates for motion errors through phase error estimation. This method can attain relatively good performance, while assuming the same phase error for all pixels, i.e., it ignores the spatial variance of motion errors. To overcome this drawback, a high-precision motion error compensation method is presented in this study. In the proposed method, the Antenna Phase Centers (APC are estimated via optimization using the criterion of maximum image intensity. Then, the estimated APCs are applied for BP imaging. Because the APC estimation equals the range history estimation for each pixel, high-precision phase compensation for every pixel can be achieved. Point-target simulations and processing of experimental data validate the effectiveness of the proposed method.

Patient-Centered Robot-Aided Passive Neurorehabilitation Exercise Based on Safety-Motion Decision-Making Mechanism

Directory of Open Access Journals (Sweden)

Lizheng Pan

2017-01-01

Full Text Available Safety is one of the crucial issues for robot-aided neurorehabilitation exercise. When it comes to the passive rehabilitation training for stroke patients, the existing control strategies are usually just based on position control to carry out the training, and the patient is out of the controller. However, to some extent, the patient should be taken as a “cooperator” of the training activity, and the movement speed and range of the training movement should be dynamically regulated according to the internal or external state of the subject, just as what the therapist does in clinical therapy. This research presents a novel motion control strategy for patient-centered robot-aided passive neurorehabilitation exercise from the point of the safety. The safety-motion decision-making mechanism is developed to online observe and assess the physical state of training impaired-limb and motion performances and regulate the training parameters (motion speed and training rage, ensuring the safety of the supplied rehabilitation exercise. Meanwhile, position-based impedance control is employed to realize the trajectory tracking motion with interactive compliance. Functional experiments and clinical experiments are investigated with a healthy adult and four recruited stroke patients, respectively. The two types of experimental results demonstrate that the suggested control strategy not only serves with safety-motion training but also presents rehabilitation efficacy.

Linear Extended State Observer-Based Motion Synchronization Control for Hybrid Actuation System of More Electric Aircraft

Directory of Open Access Journals (Sweden)

Xingjian Wang

2017-10-01

Full Text Available Moving towards the more electric aircraft (MEA, a hybrid actuator configuration provides an opportunity to introduce electromechanical actuator (EMA into primary flight control. In the hybrid actuation system (HAS, an electro-hydraulic servo actuator (EHSA and an EMA operate on the same control surface. In order to solve force fighting problem in HAS, this paper proposes a novel linear extended state observer (LESO-based motion synchronization control method. To cope with the problem of unavailability of the state signals required by the motion synchronization controller, LESO is designed for EHSA and EMA to observe the state variables. Based on the observed states of LESO, motion synchronization controllers could enable EHSA and EMA to simultaneously track the desired motion trajectories. Additionally, nonlinearities, uncertainties and unknown disturbances as well as the coupling term between EHSA and EMA can be estimated and compensated by using the extended state of the proposed LESO. Finally, comparative simulation results indicate that the proposed LESO-based motion synchronization controller could reduce significant force fighting between EHSA and EMA.

Linear Extended State Observer-Based Motion Synchronization Control for Hybrid Actuation System of More Electric Aircraft

Science.gov (United States)

Liao, Rui; Shi, Cun; Wang, Shaoping

2017-01-01

Moving towards the more electric aircraft (MEA), a hybrid actuator configuration provides an opportunity to introduce electromechanical actuator (EMA) into primary flight control. In the hybrid actuation system (HAS), an electro-hydraulic servo actuator (EHSA) and an EMA operate on the same control surface. In order to solve force fighting problem in HAS, this paper proposes a novel linear extended state observer (LESO)-based motion synchronization control method. To cope with the problem of unavailability of the state signals required by the motion synchronization controller, LESO is designed for EHSA and EMA to observe the state variables. Based on the observed states of LESO, motion synchronization controllers could enable EHSA and EMA to simultaneously track the desired motion trajectories. Additionally, nonlinearities, uncertainties and unknown disturbances as well as the coupling term between EHSA and EMA can be estimated and compensated by using the extended state of the proposed LESO. Finally, comparative simulation results indicate that the proposed LESO-based motion synchronization controller could reduce significant force fighting between EHSA and EMA. PMID:29068392

An Improved Flux Observer for Field-Oriented Control of Induction Motors Based on Dual Second-Order Generalized Integrator Frequency-Locked Loop

DEFF Research Database (Denmark)

Xin, Zhen; Zhao, Rende; Blaabjerg, Frede

2017-01-01

with the conventional low-pass filter based method, the SOGI-FLL does not need compensation and can effectively attenuate the high-order harmonics in the back ElectroMotive Force (EMF). However, the dynamic performance of this method is not satisfactory because the back-EMF frequency estimated by FLL suffers from...

Evaluation of motion management strategies based on required margins

International Nuclear Information System (INIS)

Sawkey, D; Svatos, M; Zankowski, C

2012-01-01

Strategies for delivering radiation to a moving lesion each require a margin to compensate for uncertainties in treatment. These motion margins have been determined here by separating the total uncertainty into components. Probability density functions for the individual sources of uncertainty were calculated for ten motion traces obtained from the literature. Motion margins required to compensate for the center of mass motion of the clinical treatment volume were found by convolving the individual sources of uncertainty. For measurements of position at a frequency of 33 Hz, system latency was the dominant source of positional uncertainty. Averaged over the ten motion traces, the motion margin for tracking with a latency of 200 ms was 4.6 mm. Gating with a duty cycle of 33% required a mean motion margin of 3.2–3.4 mm, and tracking with a latency of 100 ms required a motion margin of 3.1 mm. Feasible reductions in the effects of the sources of uncertainty, for example by using a simple prediction algorithm to anticipate the lesion position at the end of the latency period, resulted in a mean motion margin of 1.7 mm for tracking with a latency of 100 ms, 2.4 mm for tracking with a latency of 200 ms, and 2.1–2.2 mm for the gating strategies with duty cycles of 33%. A crossover tracking latency of 150 ms was found, below which tracking strategies could take advantage of narrower motion margins than gating strategies. The methods described here provide a means to guide selection of a motion management strategy for a given patient. (paper)

SU-F-J-119: Pilot Study On the Location-Based Lung Motion Assessment

Energy Technology Data Exchange (ETDEWEB)

Lee, TK [Procure Proton Therapy Center, Oklahoma City, OK (United States); Ewald, A [McLaren Cancer Institute, Flint, MI (United States)

2016-06-15

Purpose: In most of lung treatment cases with various radiotherapy beam modalities, 4DCT images are obtained in order to define ITV. ITV is defined with the signal from motion monitoring system, e.g. RPM. However, the signal is not consistent with tumor motion because it varies with location, its size, age, gender, etc. In the present study, the location-based motion assessment is presented. Methods: 4DCT images of 70 patients were reviewed: 28-left-lung and 42-right-lung patients; 36-female and 34-male patients; the age range of 51.2–89.9; tumor-size range of 0.75–9.50cm with 25% of these adherent to bony-anatomy. Philips Big-Bore Simulation CT and RPM systems were used. The study was performed as follows. First, RPM signal and tumor motion in superior-inferior direction was compared. Second, the tumor size and its motion amplitude in all directions were measured at multiple locations. Third, the average tumor motion was calculated to assess general motion amplitudes at various locations. Results: RPM amplitude is not consistent with lung tumor motion amplitude. The tumors of similar sizes at similar location present various motion amplitude up to 1.1cm difference, but in average, the standard deviation was <0.5cm. Almost regardless of tumor sizes, the tumor motion was greatest at lower lobe location (>=1.0cm), and the smallest at upper lobe location and when adherent to bony-anatomy (<=0.5cm). Conclusion: The tumor size affects the motion amplitude less than does the tumor location. However, as the study results indicate that tumor motion has noticeable variation and so further study with more patient cases is needed. Also, for the same patient, the RPM signal presents instability of breathing, and clinically the patient with the instability of RPM breathing of <=10% is selected for respiratory-gated radiotherapy and ∼25% of patients under current study was treated. Patient-specific motion-uncertainty margins are considered to be added following further

A scalable method for parallelizing sampling-based motion planning algorithms

KAUST Repository

Jacobs, Sam Ade; Manavi, Kasra; Burgos, Juan; Denny, Jory; Thomas, Shawna; Amato, Nancy M.

2012-01-01

This paper describes a scalable method for parallelizing sampling-based motion planning algorithms. It subdivides configuration space (C-space) into (possibly overlapping) regions and independently, in parallel, uses standard (sequential) sampling-based planners to construct roadmaps in each region. Next, in parallel, regional roadmaps in adjacent regions are connected to form a global roadmap. By subdividing the space and restricting the locality of connection attempts, we reduce the work and inter-processor communication associated with nearest neighbor calculation, a critical bottleneck for scalability in existing parallel motion planning methods. We show that our method is general enough to handle a variety of planning schemes, including the widely used Probabilistic Roadmap (PRM) and Rapidly-exploring Random Trees (RRT) algorithms. We compare our approach to two other existing parallel algorithms and demonstrate that our approach achieves better and more scalable performance. Our approach achieves almost linear scalability on a 2400 core LINUX cluster and on a 153,216 core Cray XE6 petascale machine. © 2012 IEEE.

A scalable method for parallelizing sampling-based motion planning algorithms

KAUST Repository

Jacobs, Sam Ade

2012-05-01

This paper describes a scalable method for parallelizing sampling-based motion planning algorithms. It subdivides configuration space (C-space) into (possibly overlapping) regions and independently, in parallel, uses standard (sequential) sampling-based planners to construct roadmaps in each region. Next, in parallel, regional roadmaps in adjacent regions are connected to form a global roadmap. By subdividing the space and restricting the locality of connection attempts, we reduce the work and inter-processor communication associated with nearest neighbor calculation, a critical bottleneck for scalability in existing parallel motion planning methods. We show that our method is general enough to handle a variety of planning schemes, including the widely used Probabilistic Roadmap (PRM) and Rapidly-exploring Random Trees (RRT) algorithms. We compare our approach to two other existing parallel algorithms and demonstrate that our approach achieves better and more scalable performance. Our approach achieves almost linear scalability on a 2400 core LINUX cluster and on a 153,216 core Cray XE6 petascale machine. © 2012 IEEE.

Commercial Motion Sensor Based Low-Cost and Convenient Interactive Treadmill

Directory of Open Access Journals (Sweden)

Jonghyun Kim

2015-09-01

Full Text Available Interactive treadmills were developed to improve the simulation of overground walking when compared to conventional treadmills. However, currently available interactive treadmills are expensive and inconvenient, which limits their use. We propose a low-cost and convenient version of the interactive treadmill that does not require expensive equipment and a complicated setup. As a substitute for high-cost sensors, such as motion capture systems, a low-cost motion sensor was used to recognize the subject’s intention for speed changing. Moreover, the sensor enables the subject to make a convenient and safe stop using gesture recognition. For further cost reduction, the novel interactive treadmill was based on an inexpensive treadmill platform and a novel high-level speed control scheme was applied to maximize performance for simulating overground walking. Pilot tests with ten healthy subjects were conducted and results demonstrated that the proposed treadmill achieves similar performance to a typical, costly, interactive treadmill that contains a motion capture system and an instrumented treadmill, while providing a convenient and safe method for stopping.

Alert management for home healthcare based on home automation analysis.

Science.gov (United States)

Truong, T T; de Lamotte, F; Diguet, J-Ph; Said-Hocine, F

2010-01-01

Rising healthcare for elder and disabled people can be controlled by offering people autonomy at home by means of information technology. In this paper, we present an original and sensorless alert management solution which performs multimedia and home automation service discrimination and extracts highly regular home activities as sensors for alert management. The results of simulation data, based on real context, allow us to evaluate our approach before application to real data.

Bio-inspired motion detection in an FPGA-based smart camera module

International Nuclear Information System (INIS)

Koehler, T; Roechter, F; Moeller, R; Lindemann, J P

2009-01-01

Flying insects, despite their relatively coarse vision and tiny nervous system, are capable of carrying out elegant and fast aerial manoeuvres. Studies of the fly visual system have shown that this is accomplished by the integration of signals from a large number of elementary motion detectors (EMDs) in just a few global flow detector cells. We developed an FPGA-based smart camera module with more than 10 000 single EMDs, which is closely modelled after insect motion-detection circuits with respect to overall architecture, resolution and inter-receptor spacing. Input to the EMD array is provided by a CMOS camera with a high frame rate. Designed as an adaptable solution for different engineering applications and as a testbed for biological models, the EMD detector type and parameters such as the EMD time constants, the motion-detection directions and the angle between correlated receptors are reconfigurable online. This allows a flexible and simultaneous detection of complex motion fields such as translation, rotation and looming, such that various tasks, e.g., obstacle avoidance, height/distance control or speed regulation can be performed by the same compact device

Hybrid task priority-based motion control of a redundant free-floating space robot

Directory of Open Access Journals (Sweden)

Cheng ZHOU

2017-12-01

Full Text Available This paper presents a novel hybrid task priority-based motion planning algorithm of a space robot. The satellite attitude control task is defined as the primary task, while the least-squares-based non-strict task priority solution of the end-effector plus the multi-constraint task is viewed as the secondary task. Furthermore, a null-space task compensation strategy in the joint space is proposed to derive the combination of non-strict and strict task-priority motion planning, and this novel combination is termed hybrid task priority control. Thus, the secondary task is implemented in the primary task’s null-space. Besides, the transition of the state of multiple constraints between activeness and inactiveness will only influence the end-effector task without any effect on the primary task. A set of numerical experiments made in a real-time simulation system under Linux/RTAI shows the validity and feasibility of the proposed methodology. Keywords: Base attitude control, Hybrid task-priority, Motion planning, Multiple constraints, Redundant space robot

Quantification of organ motion based on an adaptive image-based scale invariant feature method

Energy Technology Data Exchange (ETDEWEB)

Paganelli, Chiara [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza L. Da Vinci 32, Milano 20133 (Italy); Peroni, Marta [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza L. Da Vinci 32, Milano 20133, Italy and Paul Scherrer Institut, Zentrum für Protonentherapie, WMSA/C15, CH-5232 Villigen PSI (Italy); Baroni, Guido; Riboldi, Marco [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza L. Da Vinci 32, Milano 20133, Italy and Bioengineering Unit, Centro Nazionale di Adroterapia Oncologica, strada Campeggi 53, Pavia 27100 (Italy)

2013-11-15

Purpose: The availability of corresponding landmarks in IGRT image series allows quantifying the inter and intrafractional motion of internal organs. In this study, an approach for the automatic localization of anatomical landmarks is presented, with the aim of describing the nonrigid motion of anatomo-pathological structures in radiotherapy treatments according to local image contrast.Methods: An adaptive scale invariant feature transform (SIFT) was developed from the integration of a standard 3D SIFT approach with a local image-based contrast definition. The robustness and invariance of the proposed method to shape-preserving and deformable transforms were analyzed in a CT phantom study. The application of contrast transforms to the phantom images was also tested, in order to verify the variation of the local adaptive measure in relation to the modification of image contrast. The method was also applied to a lung 4D CT dataset, relying on manual feature identification by an expert user as ground truth. The 3D residual distance between matches obtained in adaptive-SIFT was then computed to verify the internal motion quantification with respect to the expert user. Extracted corresponding features in the lungs were used as regularization landmarks in a multistage deformable image registration (DIR) mapping the inhale vs exhale phase. The residual distances between the warped manual landmarks and their reference position in the inhale phase were evaluated, in order to provide a quantitative indication of the registration performed with the three different point sets.Results: The phantom study confirmed the method invariance and robustness properties to shape-preserving and deformable transforms, showing residual matching errors below the voxel dimension. The adapted SIFT algorithm on the 4D CT dataset provided automated and accurate motion detection of peak to peak breathing motion. The proposed method resulted in reduced residual errors with respect to standard SIFT

Marker-Free Human Motion Capture

DEFF Research Database (Denmark)

Grest, Daniel

Human Motion Capture is a widely used technique to obtain motion data for animation of virtual characters. Commercial optical motion capture systems are marker-based. This book is about marker-free motion capture and its possibilities to acquire motion from a single viewing direction. The focus...

Influence of Visual Motion, Suggestion, and Illusory Motion on Self-Motion Perception in the Horizontal Plane.

Directory of Open Access Journals (Sweden)

Steven David Rosenblatt

Full Text Available A moving visual field can induce the feeling of self-motion or vection. Illusory motion from static repeated asymmetric patterns creates a compelling visual motion stimulus, but it is unclear if such illusory motion can induce a feeling of self-motion or alter self-motion perception. In these experiments, human subjects reported the perceived direction of self-motion for sway translation and yaw rotation at the end of a period of viewing set visual stimuli coordinated with varying inertial stimuli. This tested the hypothesis that illusory visual motion would influence self-motion perception in the horizontal plane. Trials were arranged into 5 blocks based on stimulus type: moving star field with yaw rotation, moving star field with sway translation, illusory motion with yaw, illusory motion with sway, and static arrows with sway. Static arrows were used to evaluate the effect of cognitive suggestion on self-motion perception. Each trial had a control condition; the illusory motion controls were altered versions of the experimental image, which removed the illusory motion effect. For the moving visual stimulus, controls were carried out in a dark room. With the arrow visual stimulus, controls were a gray screen. In blocks containing a visual stimulus there was an 8s viewing interval with the inertial stimulus occurring over the final 1s. This allowed measurement of the visual illusion perception using objective methods. When no visual stimulus was present, only the 1s motion stimulus was presented. Eight women and five men (mean age 37 participated. To assess for a shift in self-motion perception, the effect of each visual stimulus on the self-motion stimulus (cm/s at which subjects were equally likely to report motion in either direction was measured. Significant effects were seen for moving star fields for both translation (p = 0.001 and rotation (p0.1 for both. Thus, although a true moving visual field can induce self-motion, results of this

Setting up an off-site emergency mortuary facility (EMF) to deal with a DVI incident: disaster victim management (DVM).

Science.gov (United States)

Eitzen, David; Zimmermann, Alex

2012-06-01

Forensic mortuaries in all Australian jurisdictions are dealing with increasing workloads, with routine cases regularly occupying greater than 50%, and often as much as 85%, of existing cold room body storage capacity, particularly over long weekends and during seasonal increases in respiratory infections. Hence the need to deal with a sudden influx of deceased persons or multiple body parts in a mass fatality incident would overwhelm most Australian forensic mortuaries, thereby requiring other means of body storage and processing. Exercise "Construct" was a joint South Australian Police (SAPol) and Forensic Science South Australia exercise designed to practice the establishment and construction of an emergency mortuary facility (EMF) to deal with a mass fatality incident and the subsequent disaster victim identification process. The aims of the exercise were to test preparedness, activation and construction processes relative to the establishment of an EMF. The exercise provided the opportunity to identify gaps in the capacity to successfully complete the tasks within the allotted time frames. The exercise reinforced the need to have a comprehensive and clearly documented process which must include a current list of suppliers who can deliver goods and services in a timely manner. The aim of this paper is to report on the exercise findings and share the experience with other jurisdictions. It will also provide other jurisdictions with the opportunity to consider whether the South Australian model will be useful to them in improving their own response when confronted with a mass fatality incident that may overwhelm existing local mortuary capacities and capabilities.

Influence of Visual Motion, Suggestion, and Illusory Motion on Self-Motion Perception in the Horizontal Plane.

Science.gov (United States)

Rosenblatt, Steven David; Crane, Benjamin Thomas

2015-01-01

A moving visual field can induce the feeling of self-motion or vection. Illusory motion from static repeated asymmetric patterns creates a compelling visual motion stimulus, but it is unclear if such illusory motion can induce a feeling of self-motion or alter self-motion perception. In these experiments, human subjects reported the perceived direction of self-motion for sway translation and yaw rotation at the end of a period of viewing set visual stimuli coordinated with varying inertial stimuli. This tested the hypothesis that illusory visual motion would influence self-motion perception in the horizontal plane. Trials were arranged into 5 blocks based on stimulus type: moving star field with yaw rotation, moving star field with sway translation, illusory motion with yaw, illusory motion with sway, and static arrows with sway. Static arrows were used to evaluate the effect of cognitive suggestion on self-motion perception. Each trial had a control condition; the illusory motion controls were altered versions of the experimental image, which removed the illusory motion effect. For the moving visual stimulus, controls were carried out in a dark room. With the arrow visual stimulus, controls were a gray screen. In blocks containing a visual stimulus there was an 8s viewing interval with the inertial stimulus occurring over the final 1s. This allowed measurement of the visual illusion perception using objective methods. When no visual stimulus was present, only the 1s motion stimulus was presented. Eight women and five men (mean age 37) participated. To assess for a shift in self-motion perception, the effect of each visual stimulus on the self-motion stimulus (cm/s) at which subjects were equally likely to report motion in either direction was measured. Significant effects were seen for moving star fields for both translation (p = 0.001) and rotation (pperception was shifted in the direction consistent with the visual stimulus. Arrows had a small effect on self-motion