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1

Head and eye movement as pointing modalities for eyewear computers  

DEFF Research Database (Denmark)

While the new generation of eyewear computers have increased expectations of a wearable computer, providing input to these devices is still challenging. Hand-held devices, voice commands, and hand gestures have already been explored to provide input to the wearable devices. In this paper, we examined using head and eye movements to point on a graphical user interface of a wearable computer. The performance of users in head and eye pointing has been compared with mouse pointing as a baseline method. The result of our experiment showed that the eye pointing is significantly faster than head or mouse pointing; however, our participants thought that the head pointing is more accurate and convenient.

Jalaliniya, Shahram; Mardanbeigi, Diako

2014-01-01

2

Evaluating camouflage design using eye movement data.  

Science.gov (United States)

This study investigates the characteristics of eye movements during a camouflaged target search task. Camouflaged targets were randomly presented on two natural landscapes. The performance of each camouflage design was assessed by target detection hit rate, detection time, number of fixations on display, first saccade amplitude to target, number of fixations on target, fixation duration on target, and subjective ratings of search task difficulty. The results showed that the camouflage patterns could significantly affect the eye-movement behavior, especially first saccade amplitude and fixation duration, and the findings could be used to increase the sensitivity of the camouflage assessment. We hypothesized that the assessment could be made with regard to the differences in detectability and discriminability of the camouflage patterns. These could explain less efficient search behavior in eye movements. Overall, data obtained from eye movements can be used to significantly enhance the interpretation of the effects of different camouflage design. PMID:24139724

Lin, Chiuhsiang Joe; Chang, Chi-Chan; Lee, Yung-Hui

2014-05-01

3

Characterizing the point spread function of retinal OCT devices with a model eye-based phantom  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have designed, fabricated, and tested a nanoparticle-embedded phantom (NEP) incorporated into a model eye in order to characterize the point spread function (PSF) of retinal optical coherence tomography (OCT) devices in three dimensions under realistic imaging conditions. The NEP comprises a sparse distribution of highly backscattering silica-gold nanoshells embedded in a transparent UV-curing epoxy. The commercially-available model eye replicates the key optical structures and focusing po...

Agrawal, Anant; Connors, Megan; Beylin, Alexander; Liang, Chia-pin; Barton, David; Chen, Yu; Drezek, Rebekah A.; Pfefer, T. Joshua

2012-01-01

4

Quickest Change-Point Detection: A Bird's Eye View  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We provide a bird's eye view onto the area of sequential change-point detection. We focus on the discrete-time case with known pre- and post-change data distributions and offer a summary of the forefront asymptotic results established in each of the four major formulations of the underlying optimization problem: Bayesian, generalized Bayesian, minimax, and multi-cyclic.

Polunchenko, Aleksey S.; Sokolov, Grigory; Du, Wenyu

2013-01-01

5

Characterizing the point spread function of retinal OCT devices with a model eye-based phantom.  

Science.gov (United States)

We have designed, fabricated, and tested a nanoparticle-embedded phantom (NEP) incorporated into a model eye in order to characterize the point spread function (PSF) of retinal optical coherence tomography (OCT) devices in three dimensions under realistic imaging conditions. The NEP comprises a sparse distribution of highly backscattering silica-gold nanoshells embedded in a transparent UV-curing epoxy. The commercially-available model eye replicates the key optical structures and focusing power of the human eye. We imaged the model eye-NEP combination with a research-grade spectral domain OCT system designed for in vivo retinal imaging and quantified the lateral and axial PSF dimensions across the field of view in the OCT images. We also imaged the model eye-NEP in a clinical OCT system. Subtle features in the PSF and its dimensions were consistent with independent measurements of lateral and axial resolution. This model eye-based phantom can provide retinal OCT device developers and users a means to rapidly, objectively, and consistently assess the PSF, a fundamental imaging performance metric. PMID:22567601

Agrawal, Anant; Connors, Megan; Beylin, Alexander; Liang, Chia-Pin; Barton, David; Chen, Yu; Drezek, Rebekah A; Pfefer, T Joshua

2012-05-01

6

ATSU Point Design (gasdynamics)  

Energy Technology Data Exchange (ETDEWEB)

In this presentation the basic principles outlined in the first talk ''Gas Cell Neutralizers'' will be applied to a problem of particular interest viz., the design of a ''gasdynamic free-jet'' neutralizer for the Los Alamos ATSU project. What will be presented here does not in any way represent the final gas neutralizer design for ATSU. Rather, the material presented herein should be viewed as simply a preliminary design intended to identify and gain insight into the more subtle issues that must be considered in designing this type of gas neutralizer.

Fuehrer, B.

1985-06-01

7

Achromatic Interaction Point Design  

Energy Technology Data Exchange (ETDEWEB)

Designers of high-luminosity energy-frontier muon colliders must provide strong beam focusing in the interaction regions. However, the construction of a strong, aberration-free beam focus is difficult and space consuming, and long straight sections generate an off-site radiation problem due to muon decay neutrinos that interact as they leave the surface of the earth. Without some way to mitigate the neutrino radiation problem, the maximum c.m. energy of a muon collider will be limited to about 3.5 TeV. A new concept for achromatic low beta design is being developed, in which the interaction region telescope and optical correction elements, are installed in the bending arcs. The concept, formulated analytically, combines space economy, a preventative approach to compensation for aberrations, and a reduction of neutrino flux concentration. An analytical theory for the aberration-free, low beta, spatially compact insertion is being developed.

Guimei Wang,, Yaroslav Derbenev, S.Alex Bogacz, P. Chevtsov, Andre Afanaciev, Charles Ankenbrandt, Valentin Ivanov, Rolland P. Johnson

2009-05-01

8

Design of Eye Movement Interactive Interface and Example Development  

Directory of Open Access Journals (Sweden)

Full Text Available With the unceasing development of HCI (Human Computer Interaction technology, natural interactive products are valued by more and more people. The next generation of man-machine interface may use touch, hearing or vision, etc. Among them, the visual sense is the most important channel to get information, but researches are mostly focused on the measurement of eye movement or data processing. In the future, the interaction of eyes with machines will have a very wide prospect. After concluding the pluses and minuses of available eye control systems, we puts forth the design principle, system concept and the state transition model of eyes interaction from the consideration of user-centered design principle. The system simplifies the measurement process, focuses on the fast tracking, calibration and accurate eye movement identification. At the same time, we use context information to reduce interaction time and combines with keys to eliminate eye movements’ ambiguity. Based on the design scheme, we develop a system-EyeHUD(Eye Head Up Diaplay which can be applied in driving. It includes an eye preset interface, an eye control interface and a virtual vehicle scene. Before starting cars, a driver uses the eye tracker to track and calibrate eyes, then chooses an interactive function, like one blink zoom in or two blink chick. When the eye control interface is opened, the driver can use auto eye control to operate it, or choose eyes+keys way to simulate a click. The evaluation results shows: EyeHUD can successfully achieve all the default function and participants don’t need long time to understand the information provided by the interface. Compared with the eyes+keys way, the auto eye control has no obvious difference in recognition success rate.

Kong Xiang-Zong

2013-01-01

9

Turning points in reactor design  

International Nuclear Information System (INIS)

This article provides some historical aspects on nuclear reactor design, beginning with PWR development for Naval Propulsion and the first commercial application at Yankee Rowe. Five turning points in reactor design and some safety problems associated with them are reviewed: (1) stability of Dresden-1, (2) ECCS, (3) PRA, (4) TMI-2, and (5) advanced passive LWR designs. While the emphasis is on the thermal-hydraulic aspects, the discussion is also about reactor systems

10

Turning points in reactor design  

Energy Technology Data Exchange (ETDEWEB)

This article provides some historical aspects on nuclear reactor design, beginning with PWR development for Naval Propulsion and the first commercial application at Yankee Rowe. Five turning points in reactor design and some safety problems associated with them are reviewed: (1) stability of Dresden-1, (2) ECCS, (3) PRA, (4) TMI-2, and (5) advanced passive LWR designs. While the emphasis is on the thermal-hydraulic aspects, the discussion is also about reactor systems.

Beckjord, E.S.

1995-09-01

11

Optimization of Eye End Design of a Single Leaf Spring  

Directory of Open Access Journals (Sweden)

Full Text Available This paper is focused on determination of better eye end design and better material among Titanium and Steel for a single leaf spring. The procedure of this work is to carry out computer aided design and analysis of conventional single leaf spring with actual design considerations and loading conditions. This conventional 65Si7 spring steel leaf spring model and Titanium alloy (Ti 6Al 7Nb with standard eye end, centred eye end and Inverted eye end are considered. The CAD model of the leaf springs is prepared in PRO-E and analysed using ANSYS. Static testing and finite element analysis have been carried out to obtain the characteristics of the spring. The standard eye and centred eye leaf springs are subjected to similar loading conditions. The CAE analysis of the leaf spring is performed for various parameters like Total deflection, von-misses stress and normal stress. The main objective of this work is to determine the better eye end design and select the best material among Steel and Titanium alloy and to reduce the time and cost related to actual experimental testing by providing a CAE solution.

Jayanaidu

2014-05-01

12

Characterisation of Feature Points in Eye Fundus Images  

Science.gov (United States)

The retinal vessel tree adds decisive knowledge in the diagnosis of numerous opthalmologic pathologies such as hypertension or diabetes. One of the problems in the analysis of the retinal vessel tree is the lack of information in terms of vessels depth as the image acquisition usually leads to a 2D image. This situation provokes a scenario where two different vessels coinciding in a point could be interpreted as a vessel forking into a bifurcation. That is why, for traking and labelling the retinal vascular tree, bifurcations and crossovers of vessels are considered feature points. In this work a novel method for these retinal vessel tree feature points detection and classification is introduced. The method applies image techniques such as filters or thinning to obtain the adequate structure to detect the points and sets a classification of these points studying its environment. The methodology is tested using a standard database and the results show high classification capabilities.

Calvo, D.; Ortega, M.; Penedo, M. G.; Rouco, J.

13

Heavy ion fusion (HIF) driver point designs  

Science.gov (United States)

In this paper we report on two Heavy Ion Fusion (HIF) driver point design studies. The Robust Point Design (RPD) was completed over a year ago, and the Modular Point Design (MPD) is still in progress. The goal of any point design study is to construct a detailed design that is self-consistent and integrated from injector to target. This has been the primary theme of both studies.

Yu, S. S.; Abbott, R. P.; Bangerter, R. O.; Barnard, J. J.; Briggs, R. J.; Callahan, D.; Celata, C. M.; Davidson, R.; Debonnel, C. S.; Eylon, S.; Faltens, A.; Friedman, A.; Grote, D. P.; Heitzenroeder, P.; Henestroza, E.; Kaganovich, I.; Kwan, J. W.; Latkowski, J. F.; Lee, E. P.; Logan, B. G.; Peterson, P. F.; Rose, D.; Roy, P. K.; Sabbi, G.-L.; Seidl, P. A.; Sharp, W. M.; Welch, D. R.

2005-05-01

14

Heavy ion fusion (HIF) driver point designs  

International Nuclear Information System (INIS)

In this paper we report on two Heavy Ion Fusion (HIF) driver point design studies. The Robust Point Design (Rd) was completed over a year ago, and the Modular Point Design (MPD) is still in progress. The goal of any point design study is to construct a detailed design that is self-consistent and integrated from injector to target. This has been the primary theme of both studies

15

A TV Camera System Which Extracts Feature Points For Non-Contact Eye Movement Detection  

Science.gov (United States)

This paper proposes a highly efficient camera system which extracts, irrespective of background, feature points such as the pupil, corneal reflection image and dot-marks pasted on a human face in order to detect human eye movement by image processing. Two eye movement detection methods are sugested: One utilizing face orientation as well as pupil position, The other utilizing pupil and corneal reflection images. A method of extracting these feature points using LEDs as illumination devices and a new TV camera system designed to record eye movement are proposed. Two kinds of infra-red LEDs are used. These LEDs are set up a short distance apart and emit polarized light of different wavelengths. One light source beams from near the optical axis of the lens and the other is some distance from the optical axis. The LEDs are operated in synchronization with the camera. The camera includes 3 CCD image pick-up sensors and a prism system with 2 boundary layers. Incident rays are separated into 2 wavelengths by the first boundary layer of the prism. One set of rays forms an image on CCD-3. The other set is split by the half-mirror layer of the prism and forms an image including the regularly reflected component by placing a polarizing filter in front of CCD-1 or another image not including the component by not placing a polarizing filter in front of CCD-2. Thus, three images with different reflection characteristics are obtained by three CCDs. Through the experiment, it is shown that two kinds of subtraction operations between the three images output from CCDs accentuate three kinds of feature points: the pupil and corneal reflection images and the dot-marks. Since the S/N ratio of the subtracted image is extremely high, the thresholding process is simple and allows reducting the intensity of the infra-red illumination. A high speed image processing apparatus using this camera system is decribed. Realtime processing of the subtraction, thresholding and gravity position calculation of the feature points is possible.

Tomono, Akira; Iida, Muneo; Kobayashi, Yukio

1990-04-01

16

Innovativeness in design investigated by eye movements and pupillometry  

Directory of Open Access Journals (Sweden)

Full Text Available Innovative designs often break common visual habits by integrating more or less familiar parts into a new concept (Leder & Carbon, 2005. When design innovation is realized in an overly advanced way, the resulting designs tend to be rejected by perceivers at first glance, but seem to be favored when perceivers become more familiar with them (Carbon & Leder, 2005b. In the present study, we investigated the properties of innovative car interior designs by analyzing eye movements and the dilatation of the pupil when evaluating these designs. The analysis of eye movements indicates that innovative designs may be interpreted as more balanced in their conceptual structure. This was shown by an increased number of eye movements directed at the focus areas in car designs. Moreover, pupillometry data demonstrated that innovative designs are cognitively more demanding, thus evoking more interest. Such effects of innovativeness were particularly strong after participants had been exposed to and had elaborately dealt with the material during a phase of familiarization realized by the repeated evaluation technique.

CLAUS-CHRISTIAN CARBON

2006-06-01

17

Point prevalence of pseudoexfoliation syndrome in patients scheduled for cataract surgery in eye camps in Yemen  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: To study the point prevalence of pseudoexfoliation syndrome (PXS among Yemeni patients in different governorates with age-related cataract scheduled for surgery. Settings: Eye camps organized by the Nibras Health Society to perform cataract surgeries during the years 2002-2006. All patients aged 40 years and above were included in the study. Materials and Methods: A total of 2535 eyes of 2535 patients from 13 governorates, scheduled for cataract surgery in eye camps, were included. All eyes underwent complete eye examination before the surgery and were evaluated for the signs of pseudoexfoliation material in the pupil, iris and lens capsule on dilated slit lamp examination. Results: The study found 495 of the 2535 eyes (19.53% with PXS with males more commonly affected than females (55.2 and 44.8%, respectively. The mean age of patients with PXS was 66.2 years while it was 64.6 years in non-PXS patients. The prevalence of pseudoexfoliation syndrome increased with age (10.1% in the age group of 41-50 years that increased to 28.8% in the age group of more than 81 years old. The rate of PXS detection in camps in 13 governorates ranged from 13.33 to 24.22% with an overall rate of 19.53%. The lowest rate was noticed in Sana?a and the highest in Al-Dhale governorate. Conclusion: This pilot study confirms that PXS was common in patients undergoing cataract surgery in Yemen with an increased detection rate with age. This study also highlights the prevalence of an ocular disease that is associated with systemic and ocular complications; however, further studies based on population studies are needed.

Al-Shaer Mutahar

2010-01-01

18

Dew inspired breathing-based detection of genetic point mutation visualized by naked eye  

Science.gov (United States)

A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions.

Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

2014-09-01

19

Inclusive Assessment at Point-of-Design  

Science.gov (United States)

Recognising assessment as a driver for learning and a key part of the student learning experience, this case study considers the impact of opening the assessment process to active student engagement as well as placing inclusivity at the heart of the assessment task at point-of-design. This case study presents an approach to assessment that both…

Keating, Neil; Zybutz, Tanya; Rouse, Karl

2012-01-01

20

Programmable N-Point FFT Design  

Directory of Open Access Journals (Sweden)

Full Text Available The FFT, Fast Fourier Transform is the most ubiquitous algorithm used for signal analysis in present-day communication systems (Example: OFDM. The general principle of FFT Algorithms is to use a Divide and Conquer approach that effectively reduces operation count. The FFT is generally computed either using a single radix or by mixed radix algorithms. Several optimization techniques have been proposed to increase efficiency while computing the Fourier Transform. This paper develops a reconfigurable FFT processor that can take any number of points as input, and is not limited to sequence lengths that are powers of the radix. The paper compares the factorized mixed radix approach with the single radix approach for computation of the FFT of a truly N-point sequence and shows that the mixed-radix approach yields better performance results. The test designs were developed in VHDL, verified in Matlab and Modelsim, and implemented using Xilinx Virtex5 LX110T FPGA.

Ramesh Bhakthavatchalu

2014-08-01

 
 
 
 
21

Design of an IRFPA point-by-point bias calibration  

Science.gov (United States)

Infrared focal plane array (IRFPA) is a key component in infrared system and thermal imaging devices, widely applied in military and civilian fields, with a huge market potential and prospects. IRFPA readout circuit technology and test technology in its research occupies an important position, related to the ability to accurately and efficiently obtain the IRFPA signal and the ability of IRFPA devices for accurate performance evaluation. This paper uses an IRFPA point-by-point bias calibration, through a series of accurate timing control signals to read and save the calibration data and external input, effectively increases the point-by-point bias control accuracy, and finally improves the quality of the output image.

He, Wei; Lv, Jian; Zhou, Yun; Du, Yiying; Yu, Caideng; Xie, Guangzhong; Yuan, Kai

2012-10-01

22

Intraocular lens design for treating high myopia based on individual eye model  

Science.gov (United States)

In this research, we firstly design the phakic intraocular lens (PIOL) based on individual eye model with optical design software ZEMAX. The individual PIOL is designed to correct the defocus and astigmatism, and then we compare the PIOL power calculated from the individual eye model with that from the experiential formula. Close values of PIOL power are obtained between the individual eye model and the formula, but the suggested method has more accuracy with more functions. The impact of PIOL decentration on human eye is evaluated, including rotation decentration, flat axis decentration, steep axis decentration and axial movement of PIOL, which is impossible with traditional method. To control the PIOL decentration errors, we give the limit values of PIOL decentration for the specific eye in this study.

Wang, Yang; Wang, Zhaoqi; Wang, Yan; Zuo, Tong

2007-02-01

23

Mars interplanetary trajectory design via Lagrangian points  

Science.gov (United States)

With the increase in complexities of interplanetary missions, the main focus has shifted to reducing the total delta-V for the entire mission and hence increasing the payload capacity of the spacecraft. This paper develops a trajectory to Mars using the Lagrangian points of the Sun-Earth system and the Sun-Mars system. The whole trajectory can be broadly divided into three stages: (1) Trajectory from a near-Earth circular parking orbit to a halo orbit around Sun-Earth Lagrangian point L2. (2) Trajectory from Sun-Earth L2 halo orbit to Sun-Mars L1 halo orbit. (3) Sun-Mars L1 halo orbit to a circular orbit around Mars. The stable and unstable manifolds of the halo orbits are used for halo orbit insertion. The intermediate transfer arcs are designed using two-body Lambert's problem. The total delta-V for the whole trajectory is computed and found to be lesser than that for the conventional trajectories. For a 480 km Earth parking orbit, the total delta-V is found to be 4.6203 km/s. Another advantage in the present approach is that delta-V does not depend upon the synodic period of Earth with respect to Mars.

Eapen, Roshan Thomas; Sharma, Ram Krishan

2014-09-01

24

Design of the stereoscopic eye-tracking system for quantitative remote sensing applications  

Science.gov (United States)

Spatial and temporal data derived from eye movements, compiled while the human eye observes geospatial imagery, retain meaningful and usable information. When human perceives the stereo effect, the virtual three dimensional (3D) model resulting from eye-brain interaction is generated in the mind. If the eye movements are recorded while the virtual model is observed, it is possible to reconstruct a 3D geometrical model almost identical to the one generated in the human brain. Information obtained from eye-movements can be utilized in many ways for remote sensing applications such as geospatial image analysis and interpretation. There are various eyetracking systems available on the market; however, none of them is designed to work with stereoscopic imagery. We explore different approaches and designs of the most suitable and non-intrusive scheme for stereoscopic image viewing in the eye-tracking systems to observe and analyze 3D visual models. The design of the proposed system is based on the optical separation method, which provides visually comfortable environment for perception of stereoscopic imagery. A proof of concept solution is based on multiple mirror-lens assembly that provides a significant reduction of geometrical constrains in eye-frame capturing. Two projected solutions: for wide-angle of viewing and helmet-integrated eye-tracker are also discussed here.

Sergeyev, Aleksandr; Levin, Eugene; Roggemann, Michael C.; Gienko, Gennady

2008-08-01

25

High Pulse Repetition Rate, Eye Safe, Visible Wavelength Lidar Systems: Design, Results and Potential  

Science.gov (United States)

In 1993 the first of the eye safe visible wavelength lidar systems known now as Micro Pulse Lidar (MPL) became operational. Since that time there have been several dozen of these systems produced and applied for full time profiling of atmospheric cloud and aerosol structure. There is currently an observational network of MPL sites to support global climate research. In the course of application of these instruments there have been significant improvements in understanding, design and performance of the systems. There are addition potential and applications beyond current practice for the high repetition rate, eye safe designs. The MPL network and the current capability, design and future potential of MPL systems are described.

Spinhirne, James; Berkoff, Timothy; Welton, Elsworth; Campbell, James; OCStarr, David (Technical Monitor)

2002-01-01

26

Dynamics and mission design near libration points  

CERN Document Server

The aim of this book is to explain, analyze and compute the kinds of motions that appear in an extended vicinity of the geometrically defined equilateral points of the Earth-Moon system, as a source of possible nominal orbits for future space missions. The methodology developed here is not specific to astrodynamics problems. The techniques are developed in such a way that they can be used to study problems that can be modeled by dynamical systems. Contents: Global Stability Zones Around the Triangular Libration Points; The Normal Form Around L 5 in the Three-dimensional RTBP; Normal Form of th

Gómez, G; Jorba, A; Masdemont, J

2001-01-01

27

Dynamics and mission design near libration points  

CERN Document Server

In this book the problem of station keeping is studied for orbits near libration points in the solar system. The main focus is on orbits near halo ones in the (Earth+Moon)-Sun system. Taking as starting point the restricted three-body problem, the motion in the full solar system is considered as a perturbation of this simplified model. All the study is done with enough generality to allow easy application to other primary-secondary systems as a simple extension of the analytical and numerical computations. Contents: Bibliographical Survey; Halo Orbits. Analytical and Numerical Study; The Neigh

Gómez, G; Simo, C; Martínez, R

2001-01-01

28

The optic chiasm: a turning point in the evolution of eye/hand coordination.  

Science.gov (United States)

The primate visual system has a uniquely high proportion of ipsilateral retinal projections, retinal ganglial cells that do not cross the midline in the optic chiasm. The general assumption is that this developed due to the selective advantage of accurate depth perception through stereopsis. Here, the hypothesis that the need for accurate eye-forelimb coordination substantially influenced the evolution of the primate visual system is presented. Evolutionary processes may change the direction of retinal ganglial cells. Crossing, or non-crossing, in the optic chiasm determines which hemisphere receives visual feedback in reaching tasks. Each hemisphere receives little tactile and proprioceptive information about the ipsilateral hand. The eye-forelimb hypothesis proposes that abundant ipsilateral retinal projections developed in the primate brain to synthesize, in a single hemisphere, visual, tactile, proprioceptive, and motor information about a given hand, and that this improved eye-hand coordination and optimized the size of the brain. If accurate eye-hand coordination was a major factor in the evolution of stereopsis, stereopsis is likely to be highly developed for activity in the area where the hands most often operate.The primate visual system is ideally suited for tasks within arm's length and in the inferior visual field, where most manual activity takes place. Altering of ocular dominance in reaching tasks, reduced cross-modal cuing effects when arms are crossed, response of neurons in the primary motor cortex to viewed actions of a hand, multimodal neuron response to tactile as well as visual events, and extensive use of multimodal sensory information in reaching maneuvers support the premise that benefits of accurate limb control influenced the evolution of the primate visual system. The eye-forelimb hypothesis implies that evolutionary change toward hemidecussation in the optic chiasm provided parsimonious neural pathways in animals developing frontal vision and visually guided forelimbs, and also suggests a new perspective on vision convergence in prey and predatory animals. PMID:23866932

Larsson, Matz

2013-01-01

29

Experimental determination of the chromatic difference of magnification of the human eye and the location of the anterior nodal point.  

Science.gov (United States)

Theory predicts that retinal image size will vary with wavelength. However, this chromatic difference of magnification (CDM) is likely to be very small (afocal lens magnification necessary to cancel the apparent frontoparallel plane tilt caused by interocular differences in wavelength. We show that (1) the ocular CDM can be considerably less than theoretical model predictions, (2) the relationship among delta Rx (wavelength-dependent refractive error), CDM, and pupil position is consistent with our theoretical model, (3) CDM increases considerably when an artificial pupil in front of the eye is used, (4) the location of the anterior nodal point of the eye may be inferred from the data, and (5) unlike in the case for delta Rx, large intersubjective differences may exist for CDM. The results suggest caution in the use of artificial pupils experimentally with polychromatic stimuli because of amplification of CDM and concomitant losses of image contrast. PMID:8478747

Zhang, X; Bradley, A; Thibos, L N

1993-02-01

30

Communication Design: Getting Your Point Across.  

Science.gov (United States)

This narrative recommends a communication design for educators to use during a variety of interactions. The strategy consists of nine components: (1) greeting/introduction (the speaker's introductory remarks should establish physical comfort, a pleasant feeling, and a professional tone); (2) anticipatory set (establishing a mind set for content to…

Setterstedt-Jarrett, Lynn M.

31

Some points of advanced alarm system design  

International Nuclear Information System (INIS)

A description of some of the more relevant questions relating to advanced alarm systems for nuclear power plant installations. The development of such alarm systems embodies three main tasks: development of formal alarm handling methods, design of alarm patterns, development of alarm analysis systems. The major aspects of these tests are dealt with and the close relation between the alarm analysis and the plant disturbance analysis procedure is emphasized. (author)

32

MSFC Three Point Docking Mechanism design review  

Science.gov (United States)

In the next few decades, we will be launching expensive satellites and space platforms that will require recovery for economic reasons, because of initial malfunction, servicing, repairs, or out of a concern for post lifetime debris removal. The planned availability of a Three Point Docking Mechanism (TPDM) is a positive step towards an operational satellite retrieval infrastructure. This study effort supports NASA/MSFC engineering work in developing an automated docking capability. The work was performed by the Grumman Space & Electronics Group as a concept evaluation/test for the Tumbling Satellite Retrieval Kit. Simulation of a TPDM capture was performed in Grumman's Large Amplitude Space Simulator (LASS) using mockups of both parts (the mechanism and payload). Similar TPDM simulation activities and more extensive hardware testing was performed at NASA/MSFC in the Flight Robotics Laboratory and Space Station/Space Operations Mechanism Test Bed (6-DOF Facility).

Schaefer, Otto; Ambrosio, Anthony

1992-12-01

33

Design point selection for an ignited ITER  

International Nuclear Information System (INIS)

The parameter choice for the ITER design is dominated by the need to achieve ignition. Different energy confinement time scalings extrapolate to different device parameters, and the final design chosen must have a reasonable chance of success under the presently favoured scalings. This study investigates the device performance over the plasma current - aspect ratio design space, using sets of simplified equations and more detailed parametric analysis codes, with a view to clarifying the acceptable parameter region. Alterations to the initial assumptions of plasma elongation, plasma safety factor and peak toroidal field, and the effect of limiting the wall load, are also investigated. The study concludes that a device with aspect ratio around 3 and plasma current about 20 MA would be an appropriate choice. Under the assumptions of the study such a device would have a major radius of about 5.8m and would require the attainment of enhancement factors around 1.5 over L-mode scaling. (author). 6 refs, 11 figs, 3 tabs

34

A design of near-eye 3D display based on dual-OLED  

Science.gov (United States)

This paper provides a review of 3D display technology and a design of Near-Eye 3D Display (NE3D). In present, image quality and visual comfort are the main problems of 3D display. We designed a NE3D with using the latest 0.5 inch OLED microdisplay chips, and it contains dual-OLED and two freeform lenses, which provides the left- and right-eye image of a side-by-side displayed stereo pair to the appropriate eye. It is a "free view" 3D display technology, and interocular crosstalk was eliminated completely by using direction multiplex. Crosstalk is one of the largest contributing factors to cause visual discomfort. The paper detailed the OLED microdisplay, and gave the parameters of optical system for a compact head-mounted display. Some future works were also referred.

Chen, Zaiqing; Shi, Junsheng; Yun, Lijun; Tai, Yonghang

2010-07-01

35

Design and performance evaluation of a silicon eye using micromirrors  

Science.gov (United States)

We have developed a new paradigm, based on massively parallel analog processing coupled with a MEMS micromirror device, for developing intelligent vision systems that is capable of performing adaptive optics at rates exceeding 1 kHz and 3D imaging at bandwidths exceeding 100 Hz. The design and modeling methodologies associated with our smart vision chip are presented along with experimental results that characterize its performance. We also present design and modeling methodologies of our micromirror devices along with experimental result that characterize their performance in typical adaptive optic systems. Finally, we present modeling and simulation methodologies of adaptive optics systems along with experimental results used to design and test an adaptive optic system. The design and modeling methodologies that are presented lend themselves to facilitating the design and development of a wide variety other sophisticated vision systems. In addition to speed, our approach offers advantages in low cost batch fabrication, compact size, low power consumption, and radiation tolerance, making it ideal for many applications.

Clark, Natalie; Furth, Paul

1999-10-01

36

Fusion Nuclear Science Facility Design Points  

Science.gov (United States)

A Fusion Nuclear Science Facility (FNSF) is needed to fill the gaps between ITER and current experiments and a fusion demonstration power plant (DEMO). Characteristics should be neutron flux at the outboard midplane of 1-2 MW/m^2, continuous operation for periods up to two weeks, a goal of a duty factor of 0.3 on a year and fluences of 3-6 MW-yr/m^2 in ten years of operation to enable development of blankets suitable for tritium, electricity, and hydrogen production. Systems code analysis that implements constant physics and technology assumptions over a wide range of aspect ratio has been updated for more detailed design considerations and neutronics calculations. Conventional copper-coil tokamaks with inboard breeding/shielding and an OH solenoid optimize at high aspect ratio with devices between DIII-D and JET in size. Removal of the inboard breeding/shielding and OH coil results in the distinct ST branch with devices about half the size and A < 1.8. All these devices are generally Q < 5 but possible avenues to higher Q will be discussed.

Stambaugh, R. D.; Chan, V. S.; Garofalo, A. M.; Smith, J. P.; Wong, C. P. C.

2009-11-01

37

The Tromsø Eye Study : study design, methodology and results on visual acuity and refractive errors  

DEFF Research Database (Denmark)

Purpose:? To describe the study design and methodology of the Tromsø Eye Study (TES), and to describe visual acuity and refractive error in the study population. Methods:? The Tromsø Eye Study is a sub-study of the Tromsø Study, a population-based multipurpose longitudinal study in the municipality of Tromsø, Norway. The Tromsø Eye Study was a part of the sixth survey of the Tromsø Study, conducted from October 2007 through December 2008. The eye examination included information on self-reported eye diseases, assessment of visual acuity and refractive errors, retinal photography and optical coherence tomography. Retinal images were graded for diabetic retinopathy and age-related macular degeneration, and with computer-assisted measurements of arteriolar and venular diameters. In addition, TES researchers have access to the large comprehensive Tromsø Study database including physical examination results, carotid artery ultrasound, electrocardiogram, bone densitometry, cognitive tests, questionnaires, DNA, blood and urine samples and more from the present and the five previous surveys. Results:? Visual acuity was assessed in 6459 subjects and refraction in 6566 subjects aged 38-87?years. Snellen visual acuity

SjØlie, Anne K

2013-01-01

38

Practical guide to saddle-point construction in lens design:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Saddle-point construction (SPC) is a new method to insert lenses into an existing design. With SPC, by inserting and extracting lenses new system shapes can be obtained very rapidly, and we believe that, if added to the optical designer’s arsenal, this new tool can significantly increase design productivity in certain situations. Despite the fact that the theory behind SPC contains mathematical concepts that are still unfamiliar to many optical designers, the practical implementation of the...

Bociort, F.; Turnhout, M.; Marinescu, O.

2007-01-01

39

Designing a Secure Point-of-Sale System  

DEFF Research Database (Denmark)

This paper describes some experiences with using the ''Common Criteria for Information Security Evaluation'' as the basis for a design methodology when designing secure systems. As an example, the design process for a Point-of-Sale (POS) system is described.

Sharp, Robin

2006-01-01

40

A 34-meter VAWT (Vertical Axis Wind Turbine) point design  

Science.gov (United States)

The Wind Energy Division at Sandia National Laboratories recently completed a point design based on the 34-m Vertical Axis Wind Turbine (VAWT) Test Bed. The 34-m Test Bed research machine incorporates several innovations that improve Darrieus technology, including increased energy production, over previous machines. The point design differs minimally from the Test Bed; but by removing research-related items, its estimated cost is substantially reduced. The point design is a first step towards a Test-Bed-based commercial machine that would be competitive with conventional sources of power in the mid-1990s.

Ashwill, T. D.; Berg, D. E.; Dodd, H. M.; Rumsey, M. A.; Sutherland, H. J.; Veers, P. S.

 
 
 
 
41

Microsoft Office SharePoint Designer 2007 Step by Step  

CERN Document Server

The smart way to learn Office SharePoint Designer 2007-one step at a time! Work at your own pace through the easy numbered steps, practice files on CD, helpful hints, and troubleshooting tips to master the fundamentals of building customized SharePoint sites and applications. You'll learn how to work with Windows® SharePoint Services 3.0 and Office SharePoint Server 2007 to create Web pages complete with Cascading Style Sheets, Lists, Libraries, and customized Web parts. Then, make your site really work for you by adding data sources, including databases, XML data and Web services, and RSS fe

Coventry, Penelope

2008-01-01

42

Investigation of designated eye position and viewing zone for a two-view autostereoscopic display.  

Science.gov (United States)

Designated eye position (DEP) and viewing zone (VZ) are important optical parameters for designing a two-view autostereoscopic display. Although much research has been done to date, little empirical evidence has been found to establish a direct relationship between design and measurement. More rigorous studies and verifications to investigate DEP and to ascertain the VZ criterion will be valuable. We propose evaluation metrics based on equivalent luminance (EL) and binocular luminance (BL) to figure out DEP and VZ for a two-view autostereoscopic display. Simulation and experimental results prove that our proposed evaluation metrics can be used to find the DEP and VZ accurately. PMID:24663794

Huang, Kuo-Chung; Chou, Yi-Heng; Lin, Lang-chin; Lin, Hoang Yan; Chen, Fu-Hao; Liao, Ching-Chiu; Chen, Yi-Han; Lee, Kuen; Hsu, Wan-Hsuan

2014-02-24

43

Progress and prospects for an FI relevant point design  

Energy Technology Data Exchange (ETDEWEB)

The physics issues involved in scaling from sub ignition to high gain fast ignition are discussed. Successful point designs must collimate the electrons and minimize the stand off distance to avoid multi mega-joule ignition energies. Collimating B field configurations are identified and some initial designs are explored.

Key, M; Amendt, P; Bellei, C; Clark, D; Cohen, B; Divol, L; Ho, D; Kemp, A; Larson, D; Marinak, M; Patel, P; Shay, H; Strozzi, D; Tabak, M

2011-11-02

44

Design of an ultra-thin near-eye display with geometrical waveguide and freeform optics.  

Science.gov (United States)

Small thickness and light weight are two important requirements for a see-through near-eye display which are achieved in this paper by using two advanced technologies: geometrical waveguide and freeform optics. A major problem associated with the geometrical waveguide is the stray light which can severely degrade the display quality. The causes and solutions to this problem are thoroughly studied. A mathematical model of the waveguide is established and a non-sequential ray tracing algorithm is developed, which enable us to carefully examine the stray light of the planar waveguide and explore a global searching method to find an optimum design with the least amount of stray light. A projection optics using freeform surfaces on a wedge shaped prism is also designed. The near-eye display integrating the projection optics and the waveguide has a field of view of 28°, an exit pupil diameter of 9.6mm and an exit pupil distance of 20mm. In our final design, the proportion of the stray light energy over the image output energy of the waveguide is reduced to 2%, the modulation transfer function values across the entire field of the eyepiece are above 0.5 at 30 line pairs/mm (lps/mm). A proof-of-concept prototype of the proposed geometrical waveguide near-eye display is developed and demonstrated. PMID:25321274

Cheng, Dewen; Wang, Yongtian; Xu, Chen; Song, Weitao; Jin, Guofan

2014-08-25

45

Design of a reversible single precision floating point subtractor.  

Science.gov (United States)

In recent years, Reversible logic has emerged as a major area of research due to its ability to reduce the power dissipation which is the main requirement in the low power digital circuit design. It has wide applications like low power CMOS design, Nano-technology, Digital signal processing, Communication, DNA computing and Optical computing. Floating-point operations are needed very frequently in nearly all computing disciplines, and studies have shown floating-point addition/subtraction to be the most used floating-point operation. However, few designs exist on efficient reversible BCD subtractors but no work on reversible floating point subtractor. In this paper, it is proposed to present an efficient reversible single precision floating-point subtractor. The proposed design requires reversible designs of an 8-bit and a 24-bit comparator unit, an 8-bit and a 24-bit subtractor, and a normalization unit. For normalization, a 24-bit Reversible Leading Zero Detector and a 24-bit reversible shift register is implemented to shift the mantissas. To realize a reversible 1-bit comparator, in this paper, two new 3x3 reversible gates are proposed The proposed reversible 1-bit comparator is better and optimized in terms of the number of reversible gates used, the number of transistor count and the number of garbage outputs. The proposed work is analysed in terms of number of reversible gates, garbage outputs, constant inputs and quantum costs. Using these modules, an efficient design of a reversible single precision floating point subtractor is proposed. Proposed circuits have been simulated using Modelsim and synthesized using Xilinx Virtex5vlx30tff665-3. The total on-chip power consumed by the proposed 32-bit reversible floating point subtractor is 0.410 W. PMID:24455466

Anantha Lakshmi, Av; Sudha, Gf

2014-01-01

46

Generalizations of fuzzy linguistic control points in geometric design  

Science.gov (United States)

Control points are geometric primitives that play an important role in designing the geometry curve and surface. When these control points are blended with some basis functions, there are several geometric models such as Bezier, B-spline and NURBS(Non-Uniform Rational B-Spline) will be produced. If the control points are defined by the theory of fuzzy sets, then fuzzy geometric models are produced. But the fuzzy geometric models can only solve the problem of uncertainty complex. This paper proposes a new definition of fuzzy control points with linguistic terms. When the fuzzy control points with linguistic terms are blended with basis functions, then a fuzzy linguistic geometric model is produced. This paper ends with some numerical examples illustrating linguistic control attributes of fuzzy geometric models.

Sallehuddin, M. H.; Wahab, A. F.; Gobithaasan, R. U.

2014-07-01

47

Professional SharePoint 2010 Branding and User Interface Design  

CERN Document Server

A must have guide for creating engaging and usable SharePoint 2010 brandingWith SharePoint 2010, Microsoft has provided a more robust environment for creating collaboration and content management sites that rival any of the popular websites on the internet. Creating a branded SharePoint site involves understanding both traditional web design techniques as well as topics that are typically reserved for developers. This book bridges that gap by not only providing expert guidance for creating beautiful public facing and internal intranet sites but it also addresses the needs of those readers that

Drisgill, Randy; Sanford, Jacob J; Stubbs, Paul; Riemann, Larry

2010-01-01

48

Design of Floating Point Arithmetic Logic Unit with Universal Gate  

Directory of Open Access Journals (Sweden)

Full Text Available A floating point arithmetic and logic unit design using pipelining is proposed. By using pipeline with ALU design, ALU provides a high performance. With pipelining plus parallel processing concept ALU execute multiple instructions simultaneously. Floating point ALU unit is formed by combination of arithmetic modules (addition, subtraction, multiplication, division, Universal gate module. Each module is divided into sub-module. Bits selection determines which operation takes place at a particular time. In this design of universal gate perform logical operation such as AND,OR,NOT,NOR,NAND operation also in this work area and delay parameter are reduces. The design is and validated using vhdl simulation in the xilinx13.1i software.

Shraddha N. Zanjat

2014-06-01

49

Frequency of secondary cataract development in pseudophakic eyes with posterior chamber IOL of current designs in case of axial myopia  

Directory of Open Access Journals (Sweden)

Full Text Available ABSTRACT Purpose. To evaluate a frequency of secondary cataract development in different periods of postoperative follow-up after cataract phacoemulsification depending on the degree of axial myopia and the implanted IOL design. Material and methods. A retrospective analysis of secondary cataract formation in the long-term follow-up after cataract phacoemulsification with foldable intraocular lens implantation was performed in 16575 eyes out of 8722 patients with emmetropia and axial myopia. The average age of patients was 74±7 years, and the follow-up period was 5 years. The eyes with associated pathology such as glaucoma, diabetic retinopathy etc, were excluded from the study. Depending on the design of implanted IOL all eyes were divided into 3 groups. The first group included 5527 eyes with the implanted B-lens IOL (Hanita, Israel. The second group included 5629 eyes with the implanted Idea IOL (XCELENS, Switzerland. The third group consisted of 5419 eyes with the implanted Acrysof natural, SA60AT IOL (Alcon, USA. In every case the degree of myopia was evaluated using axial length of an eye that was measured instrumentally. The incidence of secondary cataract formation was evaluated on quantity of YAG-laser posterior capsule dissection within the 5-year follow-up after phacoemulsification with IOL implantation. Conclusion. According to our results the incidence of PCO is directly dependent on the axial length of the eye, strongly increasing in eyes with high axial myopia. The design and material of implanted IOL played an important role in PCO formation too. The eyes with the Acrysof natural, SA60AT IOL (Alcon, USA had the lowest incidence of PCO in the long-term follow-up.

G.V. Sorokoletov

2013-02-01

50

Design of Point Focusing Total-Reflection Zone Plate  

International Nuclear Information System (INIS)

We designed point focusing total-reflection zone plates (TRZPs): a double linear type TRZP in Kirkpatrick-Baez arrangement, a conical TRZP, and an open conical TRZP. In this paper, we show detail characteristics of the open conical TRZP, which is the most promising candidate for practical use, and evaluate the effect of fabrication error and misalignment on focused beam profiles by calculation

51

Effects of labeling and pointing on object gaze in boys with fragile X syndrome: An eye-tracking study.  

Science.gov (United States)

We examined the visual processing of a social learning stimulus and the ways in which visual attention was distributed to objects as well as to the examiner's face during word learning under conditions that varied only in the presence or absence of a label. The goal of the current study, then, was to evaluate the effects of differentially providing pointing and labeling during exposure to a novel target object in males with fragile X syndrome (FXS) (n=14, ages 4.33-10.02), autism spectrum disorder (ASD) (n=17, ages 4.04-10.4), or typical development (TD) (n=18, ages 2.05-5.33). In particular, the present study examined attention to the examiner's face as well as target and distracter objects that were presented as video stimuli. An eye-tracker captured gaze to the video stimuli as they were shown in order to examine the way in which children with FXS, ASD, or TD distributed their gaze toward the examiner and the objects. Results indicated that no group showed increased gaze toward the target object compared to the distracter object. However, results revealed that participants with FXS showed significantly increased face gaze compared to the novel objects, whereas children with ASD and TD both showed similar amounts of relative gaze toward the face and objects. Furthermore, the act of pointing at the target object was found to increase gaze toward the target objects compared to when there was no pointing in all groups. Together, these findings suggest that social cues like those employed in a word-learning task, when presented with video, may relate to gaze in FXS in context- or task-dependent ways that are distinct from those expected during live interaction. PMID:25062097

Benjamin, David P; Mastergeorge, Ann M; McDuffie, Andrea S; Kover, Sara T; Hagerman, Randi J; Abbeduto, Leonard

2014-11-01

52

Research on design multi-points performance curves of pump  

Science.gov (United States)

The centrifugal pump's performance curves are the most important chart to reveal relevance of different performance parameters. They can show pump's function comprehensively and graphically. However these curves can't be predicted and designed precisely, duo to the complicated flow inside the impeller and the incomplete way to design pump. The complete shape of performance curves can be gained only after test. With the development of industry, many applications need the pump operating well at different flow conditions. It means the pump's performance curves should pass some specific points. This is a problem to the designer who still uses the traditional way to design pumps. In this paper, the Design of experiments was applied to arrange a plan of experiments. Because the theory equations of performance curves contain many geometry factors of impeller, changing these factors have different influence on the shape of curves, the relationship between geometry factors and the performance under different operation points been attained after using variance analysis to deal with experiment data. The relevant regression models and graphs were drawn to help understand these relationships. Depending on the predicted values of geometry factors pump's impeller was redesigned, and the pump's performance been simulated for saving time and cost. Test shows that the shape of performance curves satisfy design objective, this example can be taken as a reference of pump's specific designs.

Li, L.; Li, H.; Xu, D. H.

2012-11-01

53

Using saddle points for challenging optical design tasks  

Science.gov (United States)

The present research is part of an effort to develop tools that make the lens design process more systematic. In typical optical design tasks, the presence of many local minima in the optical merit function landscape makes design non-trivial. With the method of Saddle Point Construction (SPC) which was developed recently ([F. Bociort and M. van Turnhout, Opt. Engineering 48, 063001 (2009)]) new local minima are obtained efficiently from known ones by adding and removing lenses in a systematic way. To illustrate how SPC and special properties of the lens design landscape can be used, we will present the step-by-step design of a wide-angle pinhole lens and the automatic design of a 9-lens system which, after further development with traditional techniques, is capable of good performance. We also give an example that shows how to visualize the saddle point that can be constructed at any surface of any design of an imaging system that is a local minimum.

Livshits, Irina; Hou, Zhe; van Grol, Pascal; Shao, Yifeng; van Turnhout, Maarten; Urbach, Paul; Bociort, Florian

2014-09-01

54

Designing AAC systems for children with autism: evidence from eye tracking research.  

Science.gov (United States)

Autism is associated with a range of language difficulties that impact communication, behaviour management, and education. Consequently, a variety of augmentative and alternative communication (AAC) strategies may be employed to support people with autism to communicate. There is a growing body of evidence concerning the visual attention of individuals with autism, which may be relevant to AAC interventions. This review draws on evidence from eye tracking research specifically to inform the design of AAC systems for people with autism. In addition, we discuss the future of AAC for individuals with autism in light of relevant technological developments, and raise questions for future research. PMID:24785660

Gillespie-Smith, Karri; Fletcher-Watson, Sue

2014-06-01

55

Eye Allergies  

Science.gov (United States)

... Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening Guidelines Home Remedies for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye ...

56

Design of a population-based study of visual impairment in India : The Andhra Pradesh eye disease study  

Directory of Open Access Journals (Sweden)

Full Text Available Reliable population-based epidemiologic data regarding vision and ocular morbidity, as well as those about the perceptions of people regarding visual impairment and eye care, are lacking for the most part in the developing world including India. These data are the basis on which effective eye care services can be developed. To meet this need we designed the Andhra Pradesh Eye Disease Study, a population-based epidemiology study of 10,000 people in the Indian state of Andhra Pradesh. The design of this study is described in this paper. Various options for the sample size, study areas, sampling procedure, and recruitment of subjects were considered. A sample size of 10,000 people, 5,000 each in the < or = 30 and > 30 years age groups, was determined to obtain reasonable confidence in estimating the prevalence of diseases and odds ratios for risk factors of interest. A multistage sampling strategy was chosen for the study which was assumed to give a design effect of 1.5 for the estimates. One urban area, Hyderabad, and three rural areas, West Godavari, Adilabad and Mahbubnagar districts, were selected in Andhra Pradesh. Interview instruments were developed to obtain detailed information about demographic data, diet, ocular and systemic history, risk factors for eye diseases, visual function, quality of life, barriers to eye care, and knowledge about eye diseases. A detailed examination procedure was devised to obtain a broad range of normative and abnormal data related to eyes and vision. A protocol was developed for doing automated visual fields, slitlamp and fundus photography. Computer databases were made in FoxPro for data entry and subsequent analysis with SPSS. Pilot studies were done to test the instruments, procedures, and logistics of the study in urban and rural areas. Information from the Andhra Pradesh Eye Disease Study is expected to help in planning and implementation of effective long-term preventive, curative, and rehabilitative eye care services in Andhra Pradesh.

Dandona Rakhi

1997-01-01

57

Phase transfer and point-spread function of the human eye determined by a new asymmetric double-pass method.  

Science.gov (United States)

A recent study has shown that the double-pass method provides a good estimate of the ocular modulation transfer function (MTF) but that it does not yield the phase transfer function (PTF) [J. Opt. Soc. Am. A 12, 195 (1995)]. Therefore, one cannot recover the true retinal point-spread function (PSF). We present a modification of the double-pass method to overcome this problem. The key is to break the symmetry between the two passes. By using an unexpanded Gaussian input beam, we produce a diffraction-limited PSF for the first passes. Then, by using a large exit pupil, we get an aberrated PSF for the second pass. The double-pass aerial image is the cross correlation of both PSF's, so that the Fourier transform of such an aerial image directly provides the true retinal PTF, up to the cutoff frequency of the effective (small), diffraction-limited entrance pupil. The resulting double-pass aerial image is a blurred version of the true retinal PSF. Thus it shows the effect not only of even symmetric aberrations but also of odd and irregular aberrations such as coma. We have explored two different ways to retrieve the true retinal PSF: (a) deblurring of the aerial image and (b) PSF reconstruction combining PTF data with conventional double-pass MTF. We present promising initial results with both artificial and real eyes. PMID:7494153

Navarro, R; Losada, M A

1995-11-01

58

A superlinear interior points algorithm for engineering design optimization  

Science.gov (United States)

We present a quasi-Newton interior points algorithm for nonlinear constrained optimization. It is based on a general approach consisting of the iterative solution in the primal and dual spaces of the equalities in Karush-Kuhn-Tucker optimality conditions. This is done in such a way to have primal and dual feasibility at each iteration, which ensures satisfaction of those optimality conditions at the limit points. This approach is very strong and efficient, since at each iteration it only requires the solution of two linear systems with the same matrix, instead of quadratic programming subproblems. It is also particularly appropriate for engineering design optimization inasmuch at each iteration a feasible design is obtained. The present algorithm uses a quasi-Newton approximation of the second derivative of the Lagrangian function in order to have superlinear asymptotic convergence. We discuss theoretical aspects of the algorithm and its computer implementation.

Herskovits, J.; Asquier, J.

1990-01-01

59

Hubble Space Telescope Pointing Control System design improvement study  

Science.gov (United States)

As part of the NASA Controls/Structures Integration Program, a study was undertaken to determine if improvements to the performance of the Hubble Space Telescope Pointing Control System could be obtained when advanced control system design techniques were applied using simulation models and telemetry data from the spacecraft. The study was managed through the Marshall Space Flight Center. Four universities and one aerospace company developed controller designs and tested their performance. This paper summarizes the goals and provides an overview of the study.

Bukley, Angelia P.

1993-01-01

60

Stochastic gradient estimation using a single design point  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We propose and analyze a black-box gradient estimation method that can estimate gradients with respect to multiple input parameters using data obtained from a single design point. We identify conditions under which the proposed estimator is unbiased and converges in mean squared error. The proposed method is applicable to problems where the input parameter can be estimated.^ We compare the proposed method to finite differences and simultaneous perturbation. Relative to these methods, the pr...

Wieland, Jamie R.

2007-01-01

 
 
 
 
61

Oil-points - Designers means to evaluate sustainability of concepts  

DEFF Research Database (Denmark)

Designers have an essential influence on product design and are therefore one target group for environmental evaluation methods. This implies, that such evaluation methods have to meet designers requirements. Evaluation of sustainability of products is often done using formal Life Cycle Assessment (LCA) methods. The different LCA based methodologies consider different environmental exchanges and are often rather complex.In this context, the authors raise the question, whether a simplified LCA method which is only based on energy considerations can be used as a tool for quick overviews. This is investigated by means of three case studies where environmental impact is estimated using the EDIP method, the Eco-indicator 95 method, and the Oil Point method proposed by the authors. It is found that the results obtained using Oil Points are in acceptable conformity with the results obtained with more complex methods. This, however, is only valid as long as chemical substances can be neglected in the considered life cycle systems. Comments from workshops with designers, where the cases were presented, are included in the paper.

Bey, Niki; Lenau, Torben Anker

1998-01-01

62

A novel design of submicron thin film point contacts  

International Nuclear Information System (INIS)

A thin film point contact design applicable to SIS-, SNS-, and microbridge-type Josephson junctions is presented, which offers potentially advanced junction characteristics (low capacitance, low stray inductance, increased quasi-particle resistance). The design philosophy is based on the fact that a point contact results if two planes having a common symmetry axis but oriented perpendicular to each other are brought into contact with each other. For the case of thin films, instead of two-dimensional planes, the cross section of the resulting ''point''-contact is defined by the thicknesses of the two thin films. Film thicknesses can be controlled much more precisely than lateral dimensions created by lithography. Hence, submicron junction geometries can be achieved using only conventional fabrication techniques. Following this idea, Josephson weak links of the ultrashort microbridge-type have been fabricated by an all-Nb technique having a 0.3-?m X 0.2-?m cross section with a R /SUB q/ I /SUB c/ product (R /SUB q/ = quasiparticle resistance, I /SUB c/ = critical current) of more than 20 mV

63

Eye Safe, Visible Wavelength Lidar Systems: Design and Operational Advances, Results and Potential  

Science.gov (United States)

In the early nineties the first of the eye safe visible wavelength lidar systems known now as Micro Pulse Lidar (MPL) became operational. The important advance of the design was a system that, unlike most existing lidar, operated at eye safe energy densities and could thus operate unattended for full time monitoring. Since that time there have been many dozens of these systems produced and applied for full time profiling of atmospheric cloud and aerosol structure. There is currently an observational network of MPL sites to support global climate research. In thc course of application of these instruments there have been significant improvements in the, design and performance of the systems. In the last half decade particularly there has been significant application and technical development of MPL systems. In this paper we review progress. The current MPL systems in use are all single wavelength systems designed for cloud and aerosol applications. For the cloud and aerosol applications, both lidar depolarization and multi wavelength measurements have significant applications. These can be accomplished with the MPL, approach. The main current challenge for the lidar network activity are in the area of the reliability, repeatability and efficiency of data processing. The network makes use of internet data downloads and automated processing. The heights of all cloud and aerosol layers are needed. The recent emphasis has been in operationally deriving aerosol extinction cross section. Future emphasis will include adding cirrus optical parameters. For operational effectiveness, improvements to simplify routine data signal calibration are being researched. Overall the MPL systems have proven very effective. A large data base of results from globally distributed sites can be easily accessed through the internet. Applications have included atmospheric model development. Validation of current global satellite observations of aerosol and clouds, including now orbital lidar observations, was a primary goal for NASA. Although sampling issues require careful consideration, results have proven useful.

Spinhirne, James; Welton, Ellsworth J.; Berkoff, Timothy; Campbell, James

2007-01-01

64

Change point analysis and assessment : An integrated methodological design  

DEFF Research Database (Denmark)

The aim of this article is to develop an analytical framework for studying processes such as continuous innovation and business development in high-tech SME clusters that transcends the traditional qualitative-quantitative divide. The article's key contribution is the conceptual integration of four existing and well-recognised but separate approaches to studying events, processes, and change, namely change-point analysis (CPA), event-history analysis (EHA), critical-incident technique (CIT), and sequence analysis (SA) into a single design framework which is especially useful for studying complex and long-term or ongoing processes.

Müller, Sabine; Neergaard, Helle

2011-01-01

65

Iodine-125 applicator designed for irradiating blood vessels growing into the cornea of the eye  

Energy Technology Data Exchange (ETDEWEB)

The invasion of the traumatized cornea by blood vessels is a well known complication is often associated with graft rejection. Graft acceptance may be improved by the induction of endarteritis with ..beta.. radiation but the corneal stroma may be so changed by the necessary dose of radiation (commonly 4500-5000 cGy in three or four fractions) as to significantly increase the risk of sloughing (Macfaul and Bedford, 1970). To overcome this problem, the authors have designed and made an /sup 125/I eye applicator to produce an extremely narrow radiation field for treating the vascularization at the base of the cornea only. The anterior part of the cornea receives a very small dose of about 11% of that given to the base and is sufficiently large to receive a 6mm corneal transplant.

Hering, E.R.; Korrubel, J.B.; Sealy, R.; Hill, J.

1989-03-01

66

Optical design of a broadband scanning adaptive optics ophthalmoscope for the mouse eye  

Science.gov (United States)

The short focal length of the mouse eye gives rise to an optically thick retina (50 D). If in addition, multiple wavelengths are to be used simultaneously to image an arbitrary combination of retinal layers, the ? 10 D of longitudinal chromatic aberration means a total of 60 D of vergence must be covered. This dictates that marginal rays will cover a wide range of angles with respect to the optical axis at the pupil of a mouse (or murine) adaptive optics ophthalmoscope, in order to section through the entire retina with any wavelength simultaneously. In this work, we discuss the compromises associated with the design of a mouse adaptive optics ophthalmoscope using off-the-shelf spherical reflective and refractive optics.

Sulai, Yusufu N.; Dubra, Alfredo

2014-03-01

67

Practical design for compact image scanner with large depth of field by compound eye system.  

Science.gov (United States)

We designed a new image scanner using the reflective optics of a compound eye system that can easily assemble plural imaging optical units (called imaging cells) and is compact with a large depth of field (DOF). Our image scanner is constructed from 32 reflective imaging cells, each of which takes an image of approximately a 10-mm field of view (FOV) that slightly overlap the adjacent imaging cells. The total image is rebuilt by combining the 32 images in post processing. We studied how to fold the optical path in the imaging cells and simplified the structure, resulting in the following three advances of our previous work: 1) greater compactness (50 × 31 mm2 in the cross section), 2) less variable optical characteristics among the imaging cells, and 3) easy assembly thanks to small number of optical components constructing the imaging cell. PMID:25089420

Kawano, Hiroyuki; Okamoto, Tatsuki; Nakajima, Hajime; Takushima, Shigeru; Toyoda, Yoshitaka; Yamanaka, Satoshi; Funakura, Tetsuo; Yamagata, Kosaku; Matsuzawa, Taku; Kunieda, Tatsuya; Minobe, Tadashi

2014-07-28

68

Design and implementation of a real time and train less eye state recognition system  

Science.gov (United States)

Eye state recognition is one of the main stages of many image processing systems such as driver drowsiness detection system and closed-eye photo correction. Driver drowsiness is one of the main causes in the road accidents around the world. In these circumstances, a fast and accurate driver drowsiness detection system can prevent these accidents. In this article, we proposed a fast algorithm for determining the state of an eye, based on the difference between iris/pupil color and white area of the eye. In the proposed method, vertical projection is used to determine the eye state. This method is suitable for hardware implementation to be used in a fast and online drowsiness detection system. The proposed method, along with other needed preprocessing stages, is implemented on Field Programmable Gate Array chips. The results show that the proposed low-complex algorithm has sufficient speed and accuracy, to be used in real-world conditions.

Dehnavi, Mohammad; Eshghi, Mohammad

2012-12-01

69

Design of Floating Point Multiplier Using Vedic Aphorisms  

Directory of Open Access Journals (Sweden)

Full Text Available The word ‘Vedic’ is extracted from the word ‘Veda’ i.e. the store-house of all knowledge. Mathematics, derived from the Veda provides one line, super fast and mental methods along with quick cross checking systems. The Vedic mathematics was rediscovered in the early twentieth century from ancient Indian sculptures (Vedas. What we call VEDIC MATHEMATICS is a mathematical elaboration of 'Sixteen Simple Mathematical formulae from the Vedas' as brought out by Sri Bharati Krishna Tirthaji. Vedic Multiplication Technique will be used to implement Floating point multiplier. For mantissa multiplication I am using Urdhva-Tiryagbhyam sutra. The underflow and over flow cases will be handled. The inputs to the multiplier in 32 bit IEEE 754 format. In this paper, I proposed the design of high speed Vedic Multiplier using the techniques of Ancient Indian Vedic Mathematics that have been modified to improve performance. Vedic Multiplication Technique is used to implement IEEE 754 Floating point multiplier. For mantissa multiplication I am using Urdhva-triyakbhyam sutra for the underflow and over flow cases are handled. The multiplier’s inputs are provided in IEEE 754, 32 bit format. The Vedic Mathematics is the ancient system of mathematics which has a unique technique of calculations based on 16 Sutras. My work has proved the efficiency of Urdhva-Tiryagbhyam, Vedic method for multiplication which strikes a difference in the actual process of multiplication. It enables parallel generation of intermediate products, eliminates unwanted multiplication steps with zeros and scaled to higher bit levels using Karatsuba algorithm with the compatibility to different data types. The Urdhva-Tiryagbhyam Sutra is most efficient Sutra (Algorithm, giving minimum delay for multiplication of all types of numbers, either small or large. I implement this multiplier using VHDL. I implement my work by Xilinx ISE tool i.e. responsible for synthesis also. For simulation I am using Modelsim 10.2a.

Pratiksha Rai

2014-05-01

70

Pointing control system design and performance evaluation of TPF coronagraph  

Science.gov (United States)

The Terrestrial Planet Finder (TPF) project aims to detect and characterize extra-solar Earth-like planets. The coronagraph telescope is one of the two mission concepts being studied. To reject the star flux and detect the planet flux in the visible light range, the coronagraph telescope must achieve a rejection ratio on the order of a billion to one. Dynamic jitter, introduced by environmental and on-board mechanical disturbances, degrades the optical performance, as characterized primarily by contrast ratio. The feasibility of using passive vibration isolation combined with active attitude and line-of-sight (LOS) control systems to stabilize the spacecraft and the optical components to the requisite level is being studied. The telescope is also required to slew between targets or rotate around the LOS. The slew mode control law must be designed to balance the need for efficient large-angle maneuvers while simultaneously avoiding the excitation of flexible modes in order to minimize settling time. This paper provides an overview of the current control design concept and sensor/actuator topology for TPF Coronagraph and illustrates the fine pointing performance of the telescope. This performance is primarily a function of the rejection of high-frequency dynamic disturbances, in this case due to reaction wheel disturbance forces/torques transmitted through the passive isolation stage. Trade studies between isolator force rejection and disturbance level reduction via wheel redesign are also presented to illustrate the requirements imposed on current technologies. Finally, the paper summarizes preliminary results on the slew/settle performance of the telescope.

Liu, Kuo-Chia; Blaurock, Carl; Mosier, Gary E.

2004-09-01

71

Design and fabrication of a freeform microlens array for a compact large-field-of-view compound-eye camera.  

Science.gov (United States)

In this research, a unique freeform microlens array was designed and fabricated for a compact compound-eye camera to achieve a large field of view. This microlens array has a field of view of 48°×48°, with a thickness of only 1.6 mm. The freeform microlens array resides on a flat substrate, and thus can be directly mounted to a commercial 2D image sensor. Freeform surfaces were used to design the microlens profiles, thus allowing the microlenses to steer and focus incident rays simultaneously. The profiles of the freeform microlenses were represented using extended polynomials, the coefficients of which were optimized using ZEMAX. To reduce crosstalk among neighboring channels, a micro aperture array was machined using high-speed micromilling. The molded microlens array was assembled with the micro aperture array, an adjustable fixture, and a board-level image sensor to form a compact compound-eye camera system. The imaging tests using the compound-eye camera showed that the unique freeform microlens array was capable of forming proper images, as suggested by design. The measured field of view of ±23.5° also matches the initial design and is considerably larger compared with most similar camera designs using conventional microlens arrays. To achieve low manufacturing cost without sacrificing image quality, the freeform microlens array was fabricated using a combination of ultraprecision diamond broaching and a microinjection molding process. PMID:22534888

Li, Lei; Yi, Allen Y

2012-04-20

72

Fast ignition integrated experiments and high-gain point design  

Science.gov (United States)

Integrated fast ignition experiments were performed at ILE, Osaka, and LLE, Rochester, in which a nanosecond driver laser implodes a deuterated plastic shell in front of the tip of a hollow metal cone and an intense ultrashort-pulse laser is injected through the cone to heat the compressed plasma. Based on the initial successful results of fast electron heating of cone-in-shell targets, large-energy short-pulse laser beam lines were constructed and became operational: OMEGA-EP at Rochester and LFEX at Osaka. Neutron enhancement due to heating with a ?kJ short-pulse laser has been demonstrated in the integrated experiments at Osaka and Rochester. The neutron yields are being analysed by comparing the experimental results with simulations. Details of the fast electron beam transport and the electron energy deposition in the imploded fuel plasma are complicated and further studies are imperative. The hydrodynamics of the implosion was studied including the interaction of the imploded core plasma with the cone tip. Theory and simulation studies are presented on the hydrodynamics of a high-gain target for a fast ignition point design.

Shiraga, H.; Nagatomo, H.; Theobald, W.; Solodov, A. A.; Tabak, M.

2014-05-01

73

Design optimization of phase-shifting point diffraction interferometer  

Science.gov (United States)

The phase-shifting point diffraction interferometer (PS/PDI) is so far the most accurate measurement tool in atwavelength interferometry of projection optics for extreme ultraviolet lithography (EUVL). The complicate interrelationships between configuration parameters of PS/PDI call for an optimization to achieve high accuracy of PS/PDI. In this paper, a novel system-level modeling approach is proposed to optimize the parameters of PS/PDI designed for visible light (?=632.8nm) concept proof experiment. The optimal reference pinhole size selection is performed by modeling pinhole spatial filtering effect using Diffraction-Based Beam Propagation (BPR) module of CODE V and in house software. The result shows that various pinhole diameters ranging from 1.6um to 2.2um should be used in our PS/PDI experiment. The test window size and grating duty cycle optimization, which is based on the spatial frequency domain analysis of PS/PDI, is conducted by modeling the entire PS/PDI system using Physical Optics Propagation (POP) module of Zemax and in house software. The optimal window size is approximately 62um for a given window-pinhole separation of 63.3um. The optimal duty cycle of grating is calculated to be 83% to obtain the maximum fringe contrast of 0.879.

Liu, Ke; Li, Yanqiu

2008-12-01

74

A simple cassette as point-of-care diagnostic device for naked-eye colorimetric bacteria detection.  

Science.gov (United States)

Effective pathogen detection is necessary for treatment of infectious diseases. Point of care (POC) devices have tremendously improved the global human heath. However, design criteria for sample processing POC devices for pathogen detection in limited infrastructure are challenging and can make a significant contribution to global health by providing rapid and sensitive detection of bacteria in food, water, and patient samples. In this paper, we demonstrate a novel portable POC diagnostic device that is simple to assemble for genetic detection of bacterial pathogens by isothermal DNA amplification. The device is fabricated with very low production cost, using simple methods and easy-to-access materials on a flexible ribbon polyethylene substrate. We showed that the device is capable of detection of 30 CFU mL(-1) of E. coli and 200 CFU mL(-1) of S. aureus in less than 1 hour. Through numerical simulations, we estimated that the device can be extended to high-throughput detection simultaneously performing a minimum of 36 analyses. This robust and sensitive detection device can be assembled and operated by non-specialist personnel, particularly for multiple bacterial pathogen detections in low-resource settings. PMID:24300967

Safavieh, Mohammadali; Ahmed, Minhaz Uddin; Sokullu, Esen; Ng, Andy; Braescu, Liliana; Zourob, Mohammed

2014-01-21

75

Eye Infections  

Science.gov (United States)

... can get infections from bacteria, fungi, or viruses. Eye infections can occur in different parts of the eye ... affect just one eye or both. Two common eye infections are Conjunctivitis - also known as pinkeye. Conjunctivitis is ...

76

Healthy Eyes  

Science.gov (United States)

... of this page please turn Javascript on. Healthy Eyes Maintaining Your Vision Click for more information Taking ... have a comprehensive dilated eye exam. Who Performs Eye Exams? An eye care professional is either an ...

77

Design and Simulation of Floating Point Multiplier Based on VHDL  

Science.gov (United States)

Multiplying floating point numbers is a critical requirement for DSP applications involving large dynamic range. This paper focuses only on single precision normalized binary interchange format targeted for Xilinx Spartan-3 FPGA based on VHDL. The multiplier was verified against Xilinx floating point multiplier core. It handles the overflow and underflow cases. Rounding is not implemented to give more precision when using the multiplier in a Multiply and Accumulate (MAC) unit.

Remadevi, R.

2013-03-01

78

LED eye safety considerations in the design of iris capture systems  

Science.gov (United States)

We have developed a standoff iris biometrics system for improved usability in access-control applications. The system employs an eye illuminator, which is composed of an array of encapsulated near-infrared light emitting diodes (NIRLEDs), which are triggered at the camera frame rate for reduced motion blur and ambient light effects. Neither the standards / recommendations for NIR laser and lamp safety, nor the LED-specific literature address all the specific aspects of LED eye-safety measurement. Therefore, we established exposure limit criteria based on a worst-case scenario combining the following: the CIE/ANSI standard/recommendations for exposure limits; concepts for maximum irradiance level and for strobing from the laser safety standards; and ad-hoc rules minimizing irradiance on the fovea, for handling LED arrays, and for LED mounting density. Although our system was determined as eye safe, future variants may require higher exposure levels and lower safety margins. We therefore discuss system configuration for accurate LED radiometric measurement that will ensure reliable eye-safety evaluation. The considerations and ad hoc rules described in this paper are not, and should not be treated as safety recommendations.

Abramovich, Gil; Wheeler, Frederick W.

2011-06-01

79

Microsoft PowerPoint - Simon Francis [NIEA event - designated chang  

CRC – designated changes Simon Francis Public sector changes Principles: • Ensure new Government departments start participating ASAP • Follow a similar process to the private sector where possible. • Allow Government...

80

PORTRAYING THE NORDIC DESIGN FROM AN INSIDE POINT OF VIEW  

Directory of Open Access Journals (Sweden)

Full Text Available Scandinavian Design. Alternative Histories is a rather technical but an easy-to-read academic work, focusing mainly on the often ignored complexity of the theme, introducing various fresh perspectives to the subject. The authors try to provide the reader with a radically different vision, constructed by clarifying many of the persistent myths of Scandinavian design.

Aida Puente Toraño

2012-01-01

 
 
 
 
81

Optimization of the NIF ignition point design hohlraum  

Science.gov (United States)

In preparation for the start of NIF ignition experiments, we have designed a porfolio of targets that span the temperature range that is consistent with initial NIF operations: 300 eV, 285 eV, and 270 eV. Because these targets are quite complicated, we have developed a plan for choosing the optimum hohlraum for the first ignition attempt that is based on this portfolio of designs coupled with early NIF experiements using 96 beams. These early experiments will measure the laser plasma instabilities of the candidate designs and will demonstrate our ability to tune symmetry in these designs. These experimental results, coupled with the theory and simulations that went into the designs, will allow us to choose the optimal hohlraum for the first NIF ignition attempt.

Callahan, D. A.; Hinkel, D. E.; Berger, R. L.; Divol, L.; Dixit, S. N.; Edwards, M. J.; Haan, S. W.; Jones, O. S.; Lindl, J. D.; Meezan, N. B.; Michel, P. A.; Pollaine, S. M.; Suter, L. J.; Town, R. P. J.; Bradley, P. A.

2008-05-01

82

Optimization of the NIF ignition point design hohlraum  

International Nuclear Information System (INIS)

In preparation for the start of NIF ignition experiments, we have designed a porfolio of targets that span the temperature range that is consistent with initial NIF operations: 300 eV, 285 eV, and 270 eV. Because these targets are quite complicated, we have developed a plan for choosing the optimum hohlraum for the first ignition attempt that is based on this portfolio of designs coupled with early NIF experiements using 96 beams. These early experiments will measure the laser plasma instabilities of the candidate designs and will demonstrate our ability to tune symmetry in these designs. These experimental results, coupled with the theory and simulations that went into the designs, will allow us to choose the optimal hohlraum for the first NIF ignition attempt

83

Protect Those Eyes  

Science.gov (United States)

Students design and build prototypes for protective eyewear. They choose different activities or sports that require protective eyewear and design a device for that particular use. Students learn about the many ways in which the eyes can be damaged and how engineers incorporate different features and materials into eyewear designs to best protect the eyes.

Integrated Teaching And Learning Program

84

Design of Farthest-Point Masks for Image Halftoning  

Directory of Open Access Journals (Sweden)

Full Text Available In an earlier paper, we briefly presented a new halftoning algorithm called farthest-point halftoning. In the present paper, this method is analyzed in detail, and a novel dispersion measure is defined to improve the simplicity and flexibility of the result. This new stochastic screen algorithm is loosely based on Kang's dispersed-dot ordered dither halftone array construction technique used as part of his microcluster halftoning method. Our new halftoning algorithm uses pixelwise measures of dispersion based on one proposed by Kang which is here modified to be more effective. In addition, our method exploits the concept of farthest-point sampling (FPS, introduced as a progressive irregular sampling method by Eldar et al. but uses a more efficient implementation of FPS in the construction of the dot profiles. The technique we propose is compared to other state-of-the-art dither-based halftoning methods in both qualitative and quantitative manners.

Ramponi G

2004-01-01

85

Design of Farthest-Point Masks for Image Halftoning  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In an earlier paper, we briefly presented a new halftoning algorithm called farthest-point halftoning. In the present paper, this method is analyzed in detail, and a novel dispersion measure is defined to improve the simplicity and flexibility of the result. This new stochastic screen algorithm is loosely based on Kang's dispersed-dot ordered dither halftone array construction technique used as part of his microcluster halftoning method. Our new halftoning algorithm uses pixelwise mea...

Ramponi G; Shahidi R; Moloney C

2004-01-01

86

Design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye  

Science.gov (United States)

Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.; this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks®. We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO®.

Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Iturbide-Jiménez, F.; Martínez-López, M.; Ramírez-Como, M.; Armengol-Cruz, V.; Vásquez-Báez, I.

2014-09-01

87

Studying nanostructured nipple arrays of moth eye facets helps to design better thin film solar cells  

International Nuclear Information System (INIS)

Nipples on the surface of moth eye facets exhibit almost perfect broadband anti-reflection properties. We have studied the facet surface micro-protuberances, known as corneal nipples, of the chestnut leafminer moth Cameraria ohridella by atomic force microscopy, and simulated the optics of the nipple arrays by three-dimensional electromagnetic simulation. The influence of the dimensions and shapes of the nipples on the optics was studied. In particular, the shape of the nipples has a major influence on the anti-reflection properties. Furthermore, we transferred the structure of the almost perfect broadband anti-reflection coatings to amorphous silicon thin film solar cells. The coating that imitates the moth-eye array allows for an increase of the short circuit current and conversion efficiency of more than 40%.

88

A Novel Fixed-Point Simulation Library for the Design of FPGAs  

Directory of Open Access Journals (Sweden)

Full Text Available Fixed-point simulation is extremely important in the design of fixed-point FPGAs. Float-point simulation is used to verify the arithmetic, while the fixed-point simulation is adopted to evaluate the performance and verify the implementation. The design of high-precision system based on FPGAs must focus on the fixed-point simulation to reduce the error acceptable even to zero. Basing on the analysis of fixed-point simulation approaches, especially the approach with MATLAB Fixed-Point Toolbox, we propose a novel fixed-point simulation library consisting of four modules. The library works under VC environment and its basic definition module imitates operating principle of MATLAB Fixed-Point Toolbox. The aim of library is to assit setting up fixed-point simulation conveniently, easily and quickly. Finally, simulation shows effect of the library.

Bingyang Liu

2010-11-01

89

Design and Implementation of IEEE-754 Addition and Subtraction for Floating Point Arithmetic Logic Unit  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes the FPGA implementation of a Decimal Floating Point (DFP adder/subtractor using IEEE 754-2008 format. In this paper we describe an efficient implementation of an IEEE 754 single precision Standard for Binary Floating-Point Arithmetic to include specifications for decimal floating-point arithmetic. As processor support for decimal floating-point arithmetic emerges, it is important to investigate efficient algorithms and hardware designs for common decimal floating-point arithmetic algorithms. This paper presents novel designs for a decimal floating-point addition and subtraction. They are fully synthesizable hardware descriptions in VERILOG. Each one is presented for high speed computing.

V.VINAY CHAMKUR , Chetana.R

2012-06-01

90

Fiber design and realization of point-by-point written fiber Bragg gratings in polymer optical fibers  

DEFF Research Database (Denmark)

An increasing interest in making sensors based on fiber Bragg gratings (FBGs) written in polymer optical fibers (POFs) has been seen recently. Mostly microstructured POFs (mPOFs) have been chosen for this purpose because they are easier to fabricate compared, for example, to step index fibers and because they allow to tune the guiding parameters by modifying the microstructure. Now a days the only technique used to write gratings in such fibers is the phase mask technique with UV light illumination. Despite the good results that have been obtained, a limited flexibility on the grating design and the very long times required for the writing of FBGs raise some questions about the possibility of exporting POF FBGs and the sensors based on them from the laboratory bench to the mass production market. The possibility of arbitrary design of fiber Bragg gratings and the very short time required to write the gratings make the point-by-point grating writing technique very interesting and would appear to be able to fill this technological gap. On the other end this technique is hardly applicable for microstructured fibers because of the writing beam being scattered by the air-holes. We report on the design and realization of a microstructured polymer optical fiber made of PMMA for direct writing of FBGs. The fiber was designed specifically to avoid obstruction of the writing beam by air-holes. The realized fiber has been used to point-by-point write a 5 mm long fourth order FBG with a Bragg wavelength of 1518 nm. The grating was inspected under Differential Interferometric Contrast microscope and the reflection spectrum was measured. This is, to the best of our knowledge, the first FBGs written into a mPOF with the point-by-point technique and also the fastest ever written into a polymer optical fiber, with less than 2.5 seconds needed.

Stefani, Alessio; Stecher, Matthias

2012-01-01

91

Optimized design of remote point diffractive optical sensors  

Science.gov (United States)

We present an optimization study of surface relief grating based sensors for use in optical remote point sensing. Our study includes the effects of geometrical characteristics of the photonic structure on the efficiencies of the first and second diffraction orders and the exhibited sensor responsivities of these orders. Our predictions are verified experimentally with measurements of surface relief gratings patterned by direct laser ablation on SiO2 sol-gel nanocomposite material with embedded NiCl2 nanocrystals developed for ammonia sensing.

Vasileiadis, M.; Alexandropoulos, D.; Karoutsos, V.; Athanasekos, L.; Sigalas, M.; Vainos, N. A.

2010-12-01

92

Optimized design of remote point diffractive optical sensors  

International Nuclear Information System (INIS)

We present an optimization study of surface relief grating based sensors for use in optical remote point sensing. Our study includes the effects of geometrical characteristics of the photonic structure on the efficiencies of the first and second diffraction orders and the exhibited sensor responsivities of these orders. Our predictions are verified experimentally with measurements of surface relief gratings patterned by direct laser ablation on SiO2 sol–gel nanocomposite material with embedded NiCl2 nanocrystals developed for ammonia sensing

93

78 FR 55629 - Special Conditions: Cirrus Design Corporation, Model SF50; Inflatable Three-Point Restraint...  

Science.gov (United States)

...Conditions No. 23-261-SC] Special Conditions: Cirrus Design Corporation, Model SF50; Inflatable Three-Point...SUMMARY: These special conditions are issued for the Cirrus Design Corporation (Cirrus), model SF50. This airplane will have...

2013-09-11

94

Eye Wear  

Science.gov (United States)

Eye wear protects or corrects your vision. Examples are Sunglasses Safety goggles Glasses (also called eyeglasses) Contact ... jobs and some sports carry a risk of eye injury. Thousands of children and adults get eye ...

95

Eye Cancer  

Science.gov (United States)

Cancer of the eye is uncommon. It can affect the outer parts of the eye, such as the eyelid, which are made up ... adults are melanoma and lymphoma. The most common eye cancer in children is retinoblastoma, which starts in ...

96

A point rainfall model for risk-based design  

Science.gov (United States)

The point rainfall model presented extends previous work on event-based rainfall models and overcomes some of their shortcomings. The model uses event-based data and can be calibrated using rainfall data substantially affected by missing or corrupted values. Particular attention was given to adequately simulating extreme storm rainfall events for use in hydrological risk assessment. The model is capable of simulating the inter-event time, storm duration, average event intensity and intra-event temporal characteristics. Conditioning of the average event rainfall intensity on rainfall duration and time of year is a feature of the model. Rainfall events are disaggregated using a conditional random walk on a dimensionless mass curve. Pluviograph data in 6 min increments from three Australian capital cities (Sydney, Brisbane and Melbourne) was used to calibrate the model parameters. It was found that the constrained random walk parameters were almost identical for the three cities. The model was tested using statistics not used in its calibration and the simulated intensity-frequency-duration extreme rainfall statistics compared very favorably with observed values. In addition, simulated aggregated statistics compared favorably with observed statistics from 30 min to monthly durations. The simulated annual rainfalls significantly underestimated the observed variability for Brisbane and Sydney, whereas satisfactorily reproduced the Melbourne variability. An explanation is offered for these differences.

Heneker, Theresa M.; Lambert, Martin F.; Kuczera, George

2001-06-01

97

Comparison of refractive error in eyes with vitrectomy, silicone oil tamponade finished phacoemulsification and intraocular lens implantation in different time point  

Directory of Open Access Journals (Sweden)

Full Text Available AIM: To compare the refractive error in eyes with vitrectomy and silicone oil tamponade finished phacoemulsification and intraocular lens(IOLimplantation in different time point. METHODS: Fifty-one patients(51 eyeswith vitrectomy and silicone oil tamponade performed phacoemulsification and IOL implantation were retrospectively analysed during 2009-01/2011-12 and divided into three groups by different time point of phacoemulsification and IOL implantation. There were 17 cases in A group performed silicone oil tamponade after vitrectomy combined with phacoemulsification and intraocular lens IOL implantation, silicone oil removal was performed after 3-6 months; 13 cases in B group performed silicone oil removal combined with phacoemulsification and IOL implantation; 21 cases in C group of scheduled phacoemulsification and IOL implantation after silicone oil removal, refractive error was compared 3months postoperatively. RESULTS: The average absolute value of refractive error was 0.873±0.256D in A group, 0.828±0.134D in B group, 0.473±0.121D in C group. There was no statistical significant difference compared with A group and B group(P>0.05, but there was statistical significant difference compared with C group and A, B group(PCONCLUSION: Axial length was measured by A Scan ultrasonograph. The refractive error was small in group of phacoemulsification and IOL implantation after silicone oil removal relatively.

Qian Shi

2013-06-01

98

Pointing Control System Design and Performance Evaluation for TPF Coronagraph  

Science.gov (United States)

The Terrestrial Planet Finder (TPF) program aims to detect and characterize extra-solar Earth-like planets. The coronagraph telescope is one of the four mission concepts being studied. In order to reject the star flux and detect the planet flux in the visible light range, the coronagraph telescope must achieve a rejection ratio on the order of a billion to one. Dynamic jitter, introduced by environmental and on-board mechanical disturbances, degrades the optical performance, as characterized primarily by contrast ratio. The feasibility of using passive vibration isolation combined with active attitude and line-of- sight control systems to stabilize the spacecraft and the optical components to the requisite level is being studied. The telescope is also required to slew between targets. The slew mode control law must be designed to balance the need for efficient large-angle maneuvers while simultaneously avoiding the excitation of flexible modes in order to minimize settling time.

Liu, Kuo-Chia; Blaurock, Carl; Mosier, Gary

2004-01-01

99

THE INFLUENCE OF EYES AND BRAIN BEHIND "ARTERMA TOOL" IN FIRST PERSON POINT OF VIEW INTERFACE OF GAMES  

Directory of Open Access Journals (Sweden)

Full Text Available The application of point of view (POV in electronic games has been vastly applied and fast becoming a favorite among electronic games (EG players particularly in games of action genre like warfare games. While allowing the users to experience the character first-hand, POV has its limitations for users. One example of the problems is the difficulty to anticipate the direction an attack by the enemy from a POV blindspot. Another problem is the difficulty to prepare a strategy. Some players become “somewhat dizzy” and eventually give up the game. This paper elaborates on the development of a framework for interactive montage on EG software interface using ArTerma tools and how the ArTerma tool works in the POV interface. Therefore, to accomplish the development of ArTerma tools, (A1(DDI2E3 model is used. In (A1(DDI2E3 model usage, ADDIE model is combined with other model concept such as “Diegesis Spatiality” concept Model, Frame concept model, and Mental concept model has been employed along side an elaboration on case studies. The study hopes that the developed a new model as well as support tool can help improve future EGs.

Irma Shayana Samaden

2014-10-01

100

A Space-Efficient Design for Reversible Floating Point Adder in Quantum Computing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reversible logic has applications in low-power computing and quantum computing. However, there are few existing designs for reversible floating-point adders and none suitable for quantum computation. In this paper we propose a space-efficient reversible floating-point adder, suitable for binary quantum computation, improving the design of Nachtigal et al. Our work focuses on improving the reversible designs of the alignment unit and the normalization unit, which are the most...

Nguyen, Trung Duc; Meter, Rodney

2013-01-01

 
 
 
 
101

Design and development of a ferroelectric micro photo detector for the bionic eye  

Science.gov (United States)

Driven by no effective therapy for Retinitis Pigmentosa and Age Related Macular Degeneration, artificial vision through the development of an artificial retina that can be implanted into the human eye, is being addressed by the Bionic Eye. This dissertation focuses on the study of a photoferroelectric micro photo detector as an implantable retinal prosthesis for vision restoration in patients with above disorders. This implant uses an electrical signal to trigger the appropriate ocular cells of the vision system without resorting to wiring or electrode implantation. The research work includes fabrication of photoferroelectric thin film micro detectors, characterization of these photoferroelectric micro devices as photovoltaic cells, and Finite Element Method (FEM) modeling of the photoferroelectrics and their device-neuron interface. A ferroelectric micro detector exhibiting the photovoltaic effect (PVE) directly adds electrical potential to the neuron membrane outer wall at the focal adhesion regions. The electrical potential then generates a retinal cell membrane potential deflection through a newly developed Direct-Electric-Field-Coupling (DEFC) model. This model is quite different from the traditional electric current model because instead of current directly working on the cell membrane, the PVE current is used to generate a localized high electric potential in the focal adhesion region by working together with the anisotropic high internal impedance of ferroelectric thin films. General electrodes and silicon photodetectors do not have such anisotropy and high impedance, and thus they cannot generate DEFC. This mechanism investigation is very valuable, because it clearly shows that our artificial retina works in a way that is totally different from the traditional current stimulation methods.

Song, Yang

102

Design and Analysis of Lightweight Pointing Mirror Used in Space Camera  

International Nuclear Information System (INIS)

Pointing mirror is one of the critical components of space camera to get earth images. Lightweighting design and simulation analysis of mirror play a major role in weight minimization and performance optimization of camera. Based on concept of design of experiments, this paper introduces a method combined curve fit with finite element simulation analysis and optimization to the lightweighting design of pointing mirror, as well as demonstrates design procedure, performance analysis and checkout of mirror. The results indicate that this method has good maneuverability and utility. This technique could be applied to lightweighting design of mirror which has a regular topological structure

103

Stauts of the Laser Inertial Fusion Energy (LIFE) Hohlraum Point Design  

Energy Technology Data Exchange (ETDEWEB)

Progress on the hohlraum point design for the LIFE engine is described. New features in the original design [Amendt et al., Fus. Sci. Technol. 60, 49 (2011)] are incorporated that address the imperatives of low target cost, high manufacturing throughput, efficient and prompt material recycling, an ability for near-term testing of key target design uncertainties on the National Ignition Facility, and robustness to target chamber environment and injection insults. To this end, the novel use of Pb hohlraums and aerogel-supported liquid DT fuel loading within a high-density-carbon (HDC) ablator is implemented in the hohlraum point design.

Amendt, P; Dunne, M; Ho, D; Lasinski, B; Meeker, D; Ross, J S

2012-04-10

104

Improvements on removing non-optimal support points in D-optimum design algorithms  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We improve the inequality used in Pronzato [2003. Removing non-optimal support points in D-optimum design algorithms. Statist. Probab. Lett. 63, 223-228] to remove points from the design space during the search for a $D$-optimum design. Let $\\xi$ be any design on a compact space $\\mathcal{X} \\subset \\mathbb{R}^m$ with a nonsingular information matrix, and let $m+\\epsilon$ be the maximum of the variance function $d(\\xi,\\mathbf{x})$ over all $\\mathbf{x} \\in \\mathcal{X}$. We pr...

Harman, Radoslav; Pronzato, Luc

2007-01-01

105

What Is Dry Eye?  

Science.gov (United States)

... Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening Guidelines Home Remedies for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye ...

106

Preventing Eye Injuries  

Science.gov (United States)

... Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening Guidelines Home Remedies for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye ...

107

Design of a precision pointing control system for the space infrared telescope facility  

Science.gov (United States)

This paper describes the design of a precision pointing control system for the Space Infrared Telescope Facility (SIRTF). Mission requirements and their impact on control system design are discussed along with the original features of the control strategy. Simulation of the total system is described, and the most significant results are presented.

Sridhar, B.; Aubrun, J.-N.; Lorell, K. R.

1986-01-01

108

Hinkley Point B Power Station, radiation protection, design philosophy and operating experience  

International Nuclear Information System (INIS)

The paper describes the major design aspects of the Hinkley Point 'B' Advanced Gas Cooled Reactor (AGR) which are required for radiation protection purposes. It includes a description of the design criteria, the predicted sources of radioactivity, radiation levels and individual exposures. Where possible, operation experience is also given. (author)

109

The design, commissioning and operation of Hinkley Point 'B' AGR power station pressure vessel insulation  

International Nuclear Information System (INIS)

The paper describes the basic design of insulation as used at Hinkley Point 'B' Advanced Gas Cooled Reactor (AGR) Power Station, together with variations of the design to suit the requirements of the different areas of the reactor. Results of commissioning tests and modifications resulting therefrom are discussed. (author)

110

The TITAN Reversed-Field Pinch Reactor: Design-point determination and parametric studies  

Energy Technology Data Exchange (ETDEWEB)

The multi-institutional TITAN study has examined the physics, technology, safety, and economics issues associated with the operation of a Reversed-Field Pinch (RFP) magnetic fusion reactor at high power density. A comprehensive system and trade study have been conducted as an integral and ongoing part of the reactor assessment. Attractive design points emerging from these parametric studies are subjected to more detailed analysis and design integration, the results of which are used to refine the parametric systems model. The design points and tradeoffs for two TITAN/RFP reactor embodiments are discussed. 14 refs.

Miller, R.L.

1987-01-01

111

Eye Injuries (For Parents)  

Science.gov (United States)

... Eyes QuizSource: Eyes Answers: Eyes Styes Quiz: Eyes Movie: Eyes Word Find: Eyes Corneal Abrasions Your Eyes ... site. Note: All information on KidsHealth® is for educational purposes only. For specific medical advice, diagnoses, and ...

112

Multi-point Adjoint-Based Design of Tilt-Rotors in a Noninertial Reference Frame  

Science.gov (United States)

Optimization of tilt-rotor systems requires the consideration of performance at multiple design points. In the current study, an adjoint-based optimization of a tilt-rotor blade is considered. The optimization seeks to simultaneously maximize the rotorcraft figure of merit in hover and the propulsive efficiency in airplane-mode for a tilt-rotor system. The design is subject to minimum thrust constraints imposed at each design point. The rotor flowfields at each design point are cast as steady-state problems in a noninertial reference frame. Geometric design variables used in the study to control blade shape include: thickness, camber, twist, and taper represented by as many as 123 separate design variables. Performance weighting of each operational mode is considered in the formulation of the composite objective function, and a build up of increasing geometric degrees of freedom is used to isolate the impact of selected design variables. In all cases considered, the resulting designs successfully increase both the hover figure of merit and the airplane-mode propulsive efficiency for a rotor designed with classical techniques.

Jones, William T.; Nielsen, Eric J.; Lee-Rausch, Elizabeth M.; Acree, Cecil W.

2014-01-01

113

The design of a precision pointing contol system for the Space Infrared Telescope Facility  

Science.gov (United States)

The design and performance simulation of the Space Infrared Telescope Facility pointing and control system are described. The system design is constrained by such considerations as image stability, maneuver capability, cryogen lifetime, and structural flexibility. The primary design driver is the requirement to rapidly execute small angle reorientations of the telescope's optical axis. The flexibility of the spacecraft was simulated using a simplified multibody model which provided an approximation of the primary bending modes. The rather conventional attitude control system design of PID type with a 0.5 Hz bandwidth was enhanced to meet the small angle maneuver requirements by the use of three techniques: (1) a feedforward loop to improve the time response; (2) torque shaping to minimize structural excitation; and (3) active image stabilization to remove residual pointing error and jitter. Simulation results indicate that the system has the desired performance and can be designed using techniques and hardware well within the state-of-the-art.

Sridhar, B.; Aurbrun, J.-N.; Lorell, K. R.

1985-01-01

114

Reliability of impingement sampling designs: An example from the Indian Point station  

International Nuclear Information System (INIS)

A 4-year data base (1976-1979) of daily fish impingement counts at the Indian Point electric power station on the Hudson River was used to compare the precision and reliability of three random-sampling designs: (1) simple random, (2) seasonally stratified, and (3) empirically stratified. The precision of daily impingement estimates improved logarithmically for each design as more days in the year were sampled. Simple random sampling was the least, and empirically stratified sampling was the most precise design, and the difference in precision between the two stratified designs was small. Computer-simulated sampling was used to estimate the reliability of the two stratified-random-sampling designs. A seasonally stratified sampling design was selected as the most appropriate reduced-sampling program for Indian Point station because: (1) reasonably precise and reliable impingement estimates were obtained using this design for all species combined and for eight common Hudson River fish by sampling only 30% of the days in a year (110 d); and (2) seasonal strata may be more precise and reliable than empirical strata if future changes in annual impingement patterns occur. The seasonally stratified design applied to the 1976-1983 Indian Point impingement data showed that selection of sampling dates based on daily species-specific impingement variability gave results that were more precise, but not more consistently reliable, than sampling allocations based on the variability ling allocations based on the variability of all fish species combined. 14 refs., 1 fig., 6 tabs

115

X-Ray Ablation and Debris Venting for the HIF Point Design  

International Nuclear Information System (INIS)

This paper presents detailed design and analysis for x-ray ablation and venting in the 120-beam, 7-MJ heavy-ion fusion (HIF) 'robust' point design. The HI Robust Point Design ('RPD-2002') is a self-consistent, non-optimized system design that has been generated as a point of reference for ongoing research in the HIF program. The point design uses a thick-liquid protected chamber, derived from HYLIFE-II - no structural surfaces face the target. A ternary salt mixture called flinabe (LiNaBeF4) has been selected for the liquid structures. Detailed two-dimensional, axially symmetric TSUNAMI calculations have been performed to determine the mass of ablation debris generated by the target x-rays following ignition and to predict the venting of the debris from the inside of the pocket into the main chamber and beam lines. These calculations provide predictions of the impulse loading to the surfaces of the liquid pocket - The closest liquid structures will experience a somewhat strong impulse, but further optimization of the design will easily decrease this impulse. The integrated mass and energy fluxes of ablation and target debris reaching the beam-line magnetic shutters are given as well: A small and acceptable magnetic dipole will prevent any debris ingression up in the final focus magnet region

116

48 CFR 47.303-15 - F.o.b. designated air carrier's terminal, point of exportation.  

Science.gov (United States)

...designated air carrier's terminal, point of exportation. 47.303-15 Section 47.303-15...designated air carrier's terminal, point of exportation. (a) Explanation of delivery term...designated air carrier's terminal, point of exportation means free of expense to the...

2010-10-01

117

48 CFR 52.247-43 - F.o.b. Designated Air Carrier's Terminal, Point of Exportation.  

Science.gov (United States)

...Designated Air Carrier's Terminal, Point of Exportation. 52.247-43 Section 52.247-43...Designated Air Carrier's Terminal, Point of Exportation. As prescribed in 47.303-15...air carrier's terminal, point of exportation: F.o.b. Designated Air...

2010-10-01

118

Eigensensitivity in integrated design. [of earth-pointing satellite's control system  

Science.gov (United States)

An application of eigensensitivity analysis to the control-structure integrated design process is presented with an emphasis placed on computational efficiency improvement of the overall design optimization process. The computational efficiency of eigenvalue/vector sensitivity analysis is demonstrated using the Earth Pointing Satellite in the context of a control-structure integrated design program. Results for a 2 percent design variable perturbation with and without the effects of the actuator mass show a 42 and 52 percent reduction in CPU time, respectively.

Kenny, Sean P.; Hou, Gene J.; Belvin, W. K.

1990-01-01

119

Unbalanced and Minimal Point Equivalent Estimation Second-Order Split-Plot Designs  

Science.gov (United States)

Restricting the randomization of hard-to-change factors in industrial experiments is often performed by employing a split-plot design structure. From an economic perspective, these designs minimize the experimental cost by reducing the number of resets of the hard-to- change factors. In this paper, unbalanced designs are considered for cases where the subplots are relatively expensive and the experimental apparatus accommodates an unequal number of runs per whole-plot. We provide construction methods for unbalanced second-order split- plot designs that possess the equivalence estimation optimality property, providing best linear unbiased estimates of the parameters; independent of the variance components. Unbalanced versions of the central composite and Box-Behnken designs are developed. For cases where the subplot cost approaches the whole-plot cost, minimal point designs are proposed and illustrated with a split-plot Notz design.

Parker, Peter A.; Kowalski, Scott M.; Vining, G. Geoffrey

2007-01-01

120

Design and performance of a prototype digital feedback system for the international linear collider interaction point  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present the design and preliminary results of a prototype beam-based digital feedback system for the Interaction Point of the International Linear Collider. A custom analogue front-end processor, FPGA-based digital signal processing board, and kicker drive amplifier have been designed, built, and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The system was measured to have a latency of approximately 140 ns.

Apsimon, R.; Burrows, Pn; Clarke, C.; Constance, B.; Dabiri Khah, H.; Hartin, T.; Perry, C.; Resta Lopez, J.; Swinson, C.; Christian, Gb; Kalinin, A.

2008-01-01

 
 
 
 
121

Improvements on removing non-optimal support points in D-optimum design algorithms  

CERN Document Server

We improve the inequality used in Pronzato [2003. Removing non-optimal support points in D-optimum design algorithms. Statist. Probab. Lett. 63, 223-228] to remove points from the design space during the search for a $D$-optimum design. Let $\\xi$ be any design on a compact space $\\mathcal{X} \\subset \\mathbb{R}^m$ with a nonsingular information matrix, and let $m+\\epsilon$ be the maximum of the variance function $d(\\xi,\\mathbf{x})$ over all $\\mathbf{x} \\in \\mathcal{X}$. We prove that any support point $\\mathbf{x}_{*}$ of a $D$-optimum design on $\\mathcal{X}$ must satisfy the inequality $d(\\xi,\\mathbf{x}_{*}) \\geq m(1+\\epsilon/2-\\sqrt{\\epsilon(4+\\epsilon-4/m)}/2)$. We show that this new lower bound on $d(\\xi,\\mathbf{x}_{*})$ is, in a sense, the best possible, and how it can be used to accelerate algorithms for $D$-optimum design.

Harman, Radoslav

2007-01-01

122

Hinkley Point 'C' power station public inquiry: proof of evidence on design and safety  

International Nuclear Information System (INIS)

A public inquiry has been set up to examine the planning application made by the Central Electricity Generating Board (CEGB) for the construction of a 1200 MW Pressurized Water Reactor power station at Hinkley Point (Hinkley Point ''C'') in the United Kingdom. The policy is to replicate the Sizewell ''B'' PWR design. The Hinkley Point ''C'' design is described indicating where changes in the Sizewell ''B'' design have been made to accommodate site differences. These are associated with the civil engineering construction and some of the electrical systems and do not affect the safety case. External hazards differ from site to site and the effect on the safety case of those specific to Hinkley Point are examined. The Chernobyl accident and the assessment of the United Kingdom PWR which was carried out subsequently are reviewed. The assessment indicated that no changes in the Sizewell ''B'' design and safety case were called for as a result of this accident; accident management developments are also reviewed, however. The CEGB's approach to minimizing occupational radiation doses is described. (UK)

123

Fuzzy Controller Design Using FPGA for Photovoltaic Maximum Power Point Tracking  

Directory of Open Access Journals (Sweden)

Full Text Available The cell has optimum operating point to be able to get maximum power. To obtain Maximum Power from photovoltaic array, photovoltaic power system usually requires Maximum Power Point Tracking (MPPT controller. This paper provides a small power photovoltaic control system based on fuzzy control with FPGA technology design and implementation for MPPT. The system composed of photovoltaic module, buck converter and the fuzzy logic controller implemented on FPGA for controlling on/off time of MOSFET switch of a buck converter. The proposed maximum power point tracking controller for photovoltaic system is tested using model designed by Matlab/Simulink program with graphical user interface (GUI for entering the parameters of any array model using information from its datasheet, Simulation and experimental results show that performance of the fuzzy controller with FPGA in a maximum power tracking of a photovoltaic array can be made use of in several photovoltaic products and obtain satisfied result.

Basil M Hamed

2012-06-01

124

Precision Pointing Control System (PPCS) system design and analysis. [for gimbaled experiment platforms  

Science.gov (United States)

The precision pointing control system (PPCS) is an integrated system for precision attitude determination and orientation of gimbaled experiment platforms. The PPCS concept configures the system to perform orientation of up to six independent gimbaled experiment platforms to design goal accuracy of 0.001 degrees, and to operate in conjunction with a three-axis stabilized earth-oriented spacecraft in orbits ranging from low altitude (200-2500 n.m., sun synchronous) to 24 hour geosynchronous, with a design goal life of 3 to 5 years. The system comprises two complementary functions: (1) attitude determination where the attitude of a defined set of body-fixed reference axes is determined relative to a known set of reference axes fixed in inertial space; and (2) pointing control where gimbal orientation is controlled, open-loop (without use of payload error/feedback) with respect to a defined set of body-fixed reference axes to produce pointing to a desired target.

Frew, A. M.; Eisenhut, D. F.; Farrenkopf, R. L.; Gates, R. F.; Iwens, R. P.; Kirby, D. K.; Mann, R. J.; Spencer, D. J.; Tsou, H. S.; Zaremba, J. G.

1972-01-01

125

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During Pregnancy Computer Usage & Eye Strain Maintaining Your Sight with Diabetes Sports and Eye Protection Eyesight Risks for Smokers Veterans & Eye Health ...

126

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During Pregnancy Computer Usage & Eye Strain Maintaining Your ... More Lifestyle Topics > EyeSmart Tips Blood Sugar and Eye Exams Control your blood sugar for several days ...

127

Down Syndrome: Eye Problems  

Science.gov (United States)

... Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision Screening Vision Screening Recommendations ... Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision Screening Vision Screening Recommendations ...

128

Dilating Eye Drops  

Science.gov (United States)

... Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision Screening Vision Screening Recommendations ... Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision Screening Vision Screening Recommendations ...

129

Compact reversed-field pinch reactors (CRFPR): sensitivity study and design-point determination  

International Nuclear Information System (INIS)

If the costing assumptions upon which the positive assessment of conventional large superconducting fusion reactors are based proves overly optimistic, approaches that promise considerably increased system power density and reduced mass utilization will be required. These more compact reactor embodiments generally must operate with reduced shield thickness and resistive magnets. Because of the unique, magnetic topology associated with the Reversed-Field Pinch (RFP), the compact reactor embodiment for this approach is particularly attractive from the viewpoint of low-field resistive coils operating with Ohmic losses that can be made small relative to the fusion power. A comprehensive system model is developed and described for a steady-state, compact RFP reactor (CRFPR). This model is used to select a unique cost-optimized design point that will be used for a conceptual engineering design. The cost-optimized CRFPR design presented herein would operate with system power densities and mass utilizations that are comparable to fission power plants and are an order of magnitude more favorable than the conventional approaches to magnetic fusion power. The sensitivity of the base-case design point to changes in plasma transport, profiles, beta, blanket thickness, normal vs superconducting coils, and fuel cycle (DT vs DD) is examined. The RFP approach is found to yield a point design for a high-power-density reactor that is surprisingly resilient to changes in key, but relatively unknown, physics and systems parameters

130

On Isotropic Sets of Points in the Plane. Application to the Design of Robot Archirectures  

CERN Document Server

Various performance indices are used for the design of serial manipulators. One method of optimization relies on the condition number of the Jacobian matrix. The minimization of the condition number leads, under certain conditions, to isotropic configurations, for which the roundoff-error amplification is lowest. In this paper, the isotropy conditions, introduced elsewhere, are the motivation behind the introduction of isotropic sets of points. By connecting together these points, we define families of isotropic manipulators. This paper is devoted to planar manipulators, the concepts being currently extended to their spatial counterparts. Furthermore, only manipulators with revolute joints are considered here.

Angeles, Jorge

2000-01-01

131

Web Design for Multiple Platforms in Microsoft SharePoint 2013  

Digital Repository Infrastructure Vision for European Research (DRIVER)

As mobile devices become more common when surfing the web there is an increasing demand of making web sites adjusted to other devices than computers. One common platform on the web is Microsoft SharePoint. In this report I look into one method of how to develop web sites that work on multiple devices in Microsoft SharePoint. I will be looking into different techniques as separate web sites compared to responsive web design. By exploring the approach of mobile first I try to find a working sol...

Claug, Erik

2013-01-01

132

At-sea test system point design for a one-third scale cold water pipe  

Energy Technology Data Exchange (ETDEWEB)

One step in the development of the technology for Ocean Thermal Energy Conversion (OTEC) Cold Water Pipes (CWP) is the at-sea testing of a fiberglass reinforced plastic nominal 10-foot diameter pipe. A design procedure and criteria for developing test hardware by scaling down a 30-foot diameter OTEC 10/40 MW Pilot Plant CWP design are presented. An example point design for the pipe, instrumentation to be used during the at-sea tests, and methods for selecting the support platform and mooring are described. The design considered starts with a scale model of a larger prototype, and then is modified to address the problems of fabrication and of survivability and handling during the 1/3rd scale model tests.

Sutherland, W.H. (ed.)

1979-12-01

133

Support points of locally optimal designs for nonlinear models with two parameters  

CERN Document Server

We propose a new approach for identifying the support points of a locally optimal design when the model is a nonlinear model. In contrast to the commonly used geometric approach, we use an approach based on algebraic tools. Considerations are restricted to models with two parameters, and the general results are applied to often used special cases, including logistic, probit, double exponential and double reciprocal models for binary data, a loglinear Poisson regression model for count data, and the Michaelis--Menten model. The approach, which is also of value for multi-stage experiments, works both with constrained and unconstrained design regions and is relatively easy to implement.

Yang, Min; 10.1214/07-AOS560

2009-01-01

134

Example of the use of point load testing and rock-quality designation  

Energy Technology Data Exchange (ETDEWEB)

This report describes the results of index testing of core from exploratory holes in the Ellalong Colliery holding area of Newcastle Wallsend Coal Company Ltd. Points load testing normal and parallel to bedding was carried out, as well as rock quality designation logging. The results were compared with the corresponding borehole logs and with the results of laboratory strength tests conducted on adjacent sections of core.

Enever, J.R.; Yeates, R.; Lees, R.

1979-01-01

135

An overview of the Hubble Space Telescope Pointing Control System design and operation  

Science.gov (United States)

An overview of the Pointing Control System (PCS) design and operational scenarios, a description of the on-orbit performance, the problems encountered, and the resulting modifications that enhance the Hubble Space Telescope mission, are presented. The PCS provides the capability to maneuver the 24,000 lb telescope 90 deg in less than 18 minutes. It also provides the primary functions of attitude reference, attitude control and stabilization.

Andersen, G. C.; Quinn, D. A.; Beals, G. A.; Nelson, J. D.; Nurre, G. S.

1992-01-01

136

Single- and Multidimensional Robustness Studies of the NIF Ignition Point Design  

Science.gov (United States)

A robustness study of the NIF ignition point-design target is carried out using hydrodynamically equivalent, all-DT direct-drive targets. The direct-drive targets have similar final mass, kinetic energy, implosion velocity, and adiabat of the indirect-drive point design. The direct-drive target has an equivalent one-dimensional ignition-threshold factor [ITF (1-D)] to the indirect-drive point design. A 1-D sensitivity study of ignition is carried out for various hot-spot conditions, gas pressures, and preheat levels. The hot-spot conditions are varied by changing the thermal conductivity. Two-dimensional studies were performed relating the yield over clean (YOC) of a hydro-equivalent THD surrogate target to fusion gain in the DT ignition target. From these studies is found the minimum THD YOC required to demonstrate ignition in the DT campaign. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement Nos. DE-FC02-ER54789 and DE-FC52-08NA28302.

Anderson, K. S.; Betti, R.; Chang, P. Y.; Nora, R.; Shvarts, D.; Fatenejad, M.

2009-11-01

137

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During Pregnancy Computer Usage & Eye Strain Maintaining Your Sight with Diabetes Sports and Eye Protection Eyesight Risks for Smokers Veterans & Eye Health More Lifestyle Topics > EyeSmart Tips Eye Protection at Home Every household should ...

138

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During Pregnancy Computer Usage & Eye Strain Maintaining Your Sight with ... Eye Protection Eyesight Risks for Smokers Veterans & Eye Health More Lifestyle Topics > EyeSmart Tips Eye Protection at ...

139

Your Eyes  

Science.gov (United States)

... with a clear, jelly-like material called the vitreous humor. Ever touch toy eyeballs in a store? Sometimes ... made to feel like they're filled with vitreous humor. In a real eye, after light passes through ...

140

Eye Injuries  

Science.gov (United States)

... that you could lose your vision. Most eye injuries are preventable. If you play sports or work in certain jobs, you may need protection. The most common type of injury happens when something irritates the ...

 
 
 
 
141

An eye on eye development.  

Science.gov (United States)

The vertebrate eye is composed of both surface ectodermal and neuroectodermal derivatives that evaginate laterally from an epithelial anlage of the forming diencephalon. The retina is composed of a limited number of neuronal and non-neuronal cell types and is seen as a model for the brain with reduced complexity. The eye develops in a stereotypic manner building on evolutionarily conserved molecular networks. Eye formation is initiated at the onset of gastrulation by the determination of the eye field in the anterior neuroectoderm. Homeobox transcription factors, in particular Six3 are crucially involved in the establishment and maintenance of retinal identity. The eye field expands by proliferation as gastrulation proceeds and is initially confined to a single retinal primordium by the differential activity of specifying transcription factors. This central field is subsequently split in response to secreted factors emanating from the ventral midline. Concomitant with medio-lateral patterning at the onset of neurulation, morphogenesis sets in and laterally evaginates the optic vesicle. Strikingly during this process the neuroectoderm in the eye field transiently loses epithelial features and cells migrate individually. In a second morphogenetic event, the vesicle is transformed into the optic cup, concomitant with onset and progression of retinal differentiation. Accompanying optic cup morphogenesis, neural differentiation is initiated from a retinal signalling centre in a stereotypic and species specific manner by secreted signalling factors. Here we will give an overview of key events during vertebrate eye formation and highlight key players in the respective processes. PMID:23684892

Sinn, Rebecca; Wittbrodt, Joachim

2013-01-01

142

What Is Dry Eye?  

Medline Plus

Full Text Available ... Torn Retina Diabetic Retinopathy Dry Eye Floaters & Flashes Glaucoma Hyperopia (Farsightedness) Low Vision Myopia (Nearsightedness) Pink Eye ( ... Remedies for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye ...

143

What Is Dry Eye?  

Medline Plus

Full Text Available ... the Sun Eye Health News Consumer Alerts What Is Dry Eye? Tweet When you blink, a film ... film, good vision would not be possible. What Is Dry Eye? Causes of Dry Eye Dry Eye ...

144

What Is Dry Eye?  

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Full Text Available ... 60 Babies, Children & Teenagers Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening Guidelines Home Remedies for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye Makeup ...

145

What Is Dry Eye?  

Medline Plus

Full Text Available ... Related Resources Related Topics Six Smart Things College Students Should Do For Their Eyes - Eye M.D.-approved information from EyeSmart Travel Tips For Your Eyes Only - Eye M.D.- ...

146

Eye Injuries (For Parents)  

Science.gov (United States)

... Free Health Lessons Social Media: Connect With Us Eye Injuries KidsHealth > Parents > First Aid & Safety > Emergencies > Eye ... do not delay flushing the eye first. Black Eye, Blunt Injury, or Contusion A black eye is ...

147

What Is Dry Eye?  

Medline Plus

Full Text Available ... Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening Guidelines Home Remedies for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye ...

148

Highly effective and accurate weak point monitoring method for advanced design rule (1x nm) devices  

Science.gov (United States)

Historically when we used to manufacture semiconductor devices for 45 nm or above design rules, IC manufacturing yield was mainly determined by global random variations and therefore the chip manufacturers / manufacturing team were mainly responsible for yield improvement. With the introduction of sub-45 nm semiconductor technologies, yield started to be dominated by systematic variations, primarily centered on resolution problems, copper/low-k interconnects and CMP. These local systematic variations, which have become decisively greater than global random variations, are design-dependent [1, 2] and therefore designers now share the responsibility of increasing yield with manufacturers / manufacturing teams. A widening manufacturing gap has led to a dramatic increase in design rules that are either too restrictive or do not guarantee a litho/etch hotspot-free design. The semiconductor industry is currently limited to 193 nm scanners and no relief is expected from the equipment side to prevent / eliminate these systematic hotspots. Hence we have seen a lot of design houses coming up with innovative design products to check hotspots based on model based lithography checks to validate design manufacturability, which will also account for complex two-dimensional effects that stem from aggressive scaling of 193 nm lithography. Most of these hotspots (a.k.a., weak points) are especially seen on Back End of the Line (BEOL) process levels like Mx ADI, Mx Etch and Mx CMP. Inspecting some of these BEOL levels can be extremely challenging as there are lots of wafer noises or nuisances that can hinder an inspector's ability to detect and monitor the defects or weak points of interest. In this work we have attempted to accurately inspect the weak points using a novel broadband plasma optical inspection approach that enhances defect signal from patterns of interest (POI) and precisely suppresses surrounding wafer noises. This new approach is a paradigm shift in wafer inspection by leveraging systematic defect locations for high sensitivity inspection, thereby enhancing the discovery and monitoring of yield-limiting defects at traditional optical inspection throughput.

Ahn, Jeongho; Seong, ShiJin; Yoon, Minjung; Park, Il-Suk; Kim, HyungSeop; Ihm, Dongchul; Chin, Soobok; Sivaraman, Gangadharan; Li, Mingwei; Babulnath, Raghav; Lee, Chang Ho; Kurada, Satya; Brown, Christine; Galani, Rajiv; Kim, JaeHyun

2014-04-01

149

Design and Performance of a Multi-Point Scan Confocal Microendoscope  

Directory of Open Access Journals (Sweden)

Full Text Available Confocal fluorescence microendoscopy provides high-resolution cellular-level imaging via a minimally invasive procedure, but requires fast scanning to achieve real-time imaging in vivo. Ideal confocal imaging performance is obtained with a point scanning system, but the scan rates required for in vivo biomedical imaging can be difficult to achieve. By scanning a line of illumination in one direction in conjunction with a stationary confocal slit aperture, very high image acquisition speeds can be achieved, but at the cost of a reduction in image quality. Here, the design, implementation, and experimental verification of a custom multi-point aperture modification to a line-scanning multi-spectral confocal microendoscope is presented. This new design improves the axial resolution of a line-scan system while maintaining high imaging rates. In addition, compared to the line-scanning configuration, previously reported simulations predicted that the multi-point aperture geometry greatly reduces the effects of tissue scatter on image quality. Experimental results confirming this prediction are presented.

Matthew D. Risi

2014-11-01

150

Design of Ultrasonically-Activatable Nanoparticles using Low Boiling Point Perfluorocarbons  

Science.gov (United States)

Recently, an interest has developed in designing in biomaterials for medical ultrasonics that can provide the acoustic activity of microbubbles, but with improved stability in vivo and a smaller size distribution for extravascular interrogation. One proposed alternative is the phase-change contrast agent. Phase-change contrast agents (PCCAs) consist of perfluorocarbons (PFCs) that are initially in liquid form, but can then be vaporized with acoustic energy. Crucial parameters for PCCAs include their sensitivity to acoustic energy, their size distribution, and their stability, and this manuscript provides insight into the custom design of PCCAs for balancing these parameters. Specifically, the relationship between size, thermal stability and sensitivity to ultrasound as a function of PFC boiling point and ambient temperature is illustrated. Emulsion stability and sensitivity can be ‘tuned’ by mixing PFCs in the gaseous state prior to condensation. Novel observations illustrate that stable droplets can be generated from PFCs with extremely low boiling points, such as octafluoropropane (b.p. ?36.7°C), which can be vaporized with acoustic parameters lower than previously observed. Results demonstrate the potential for low boiling point PFCs as a useful new class of compounds for activatable agents, which can be tailored to the desired application. PMID:22289265

Sheeran, Paul S.; Luois, Samantha; Mullin, Lee; Matsunaga, Terry O.

2012-01-01

151

Point Selection for Triangular 2-D Mesh Design Using Adaptive Forward Tracking Algorithm  

Directory of Open Access Journals (Sweden)

Full Text Available Two-dimensional mesh-based motion tracking preserves neighboring relations (through connectivity of the mesh and also allows warping transformations between pairs of frames; thus, it effectively eliminates blocking artifacts that are common in motion compensation by block matching. However, available uniform 2-D mesh model enforces connec-tivity everywhere within a frame, which is clearly not suitable across occlusion boundaries. To overcome this limitation, BTBC (background to be covered detection and MF (model failure detection algorithms are being used. In this algorithm, connectivity of the mesh elements (patches across covered and uncovered region boundaries are broken. This is achieved by allowing no node points within the background to be covered and refining the mesh structure within the model failure region at each frame. We modify the occlusion-adaptive, content-based mesh design and forward tracking algorithm used by Yucel Altunbasak for selection of points for triangular 2-D mesh design. Then, we propose a new triangulation procedure for mesh structure and also a new algorithm to justify connectivity of mesh structure after motion vector estimation of the mesh points. The modified content-based mesh is adaptive which eliminates the necessity of transmission of all node locations at each frame.

Nastaran Borjian

2011-02-01

152

Design and Implementation of Floating Point Multiplier for Better Timing Performance  

Directory of Open Access Journals (Sweden)

Full Text Available IEEE Standard 754 floating point is the most common representation today for real numbers on computers. This paper gives a brief overview of IEEE floating point and its representation. This paper describes a single precision floating point multiplier for better timing performance. The main object of this paper is to reduce the power consumption and to increase the speed of execution by implementing certain algorithm for multiplying two floating point numbers. In order to design this VHDL is the hardware description language is used and targeted on a Xilinx Spartan-3 FPGA. The implementation’s tradeoffs are area speed and accuracy. This multiplier also handles overflow and underflow cases. For high accuracy of the results normalization is also applied. By the use of pipelining process this multiplier is very good at speed and accuracy compared with the previous multipliers. This pipelined architecture is described in VHDL and is implemented on Xilinx Spartan 3 FPGA. Timing performance is measured with Xilinx Timing Analyzer. Timing performance is compared with standard multipliers.

B.Sreenivasa Ganesh,J.E.N.Abhilash, G. Rajesh Kumar

2012-09-01

153

Point design targets, specifications, and requirements for the 2010 ignition campaign on the National Ignition Facility  

Science.gov (United States)

Point design targets have been specified for the initial ignition campaign on the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 443, 2841 (2004)]. The targets contain D-T fusion fuel in an ablator of either CH with Ge doping, or Be with Cu. These shells are imploded in a U or Au hohlraum with a peak radiation temperature set between 270 and 300 eV. Considerations determining the point design include laser-plasma interactions, hydrodynamic instabilities, laser operations, and target fabrication. Simulations were used to evaluate choices, and to define requirements and specifications. Simulation techniques and their experimental validation are summarized. Simulations were used to estimate the sensitivity of target performance to uncertainties and variations in experimental conditions. A formalism is described that evaluates margin for ignition, summarized in a parameter the Ignition Threshold Factor (ITF). Uncertainty and shot-to-shot variability in ITF are evaluated, and sensitivity of the margin to characteristics of the experiment. The formalism is used to estimate probability of ignition. The ignition experiment will be preceded with an experimental campaign that determines features of the design that cannot be defined with simulations alone. The requirements for this campaign are summarized. Requirements are summarized for the laser and target fabrication.

Haan, S. W.; Lindl, J. D.; Callahan, D. A.; Clark, D. S.; Salmonson, J. D.; Hammel, B. A.; Atherton, L. J.; Cook, R. C.; Edwards, M. J.; Glenzer, S.; Hamza, A. V.; Hatchett, S. P.; Herrmann, M. C.; Hinkel, D. E.; Ho, D. D.; Huang, H.; Jones, O. S.; Kline, J.; Kyrala, G.; Landen, O. L.; MacGowan, B. J.; Marinak, M. M.; Meyerhofer, D. D.; Milovich, J. L.; Moreno, K. A.; Moses, E. I.; Munro, D. H.; Nikroo, A.; Olson, R. E.; Peterson, K.; Pollaine, S. M.; Ralph, J. E.; Robey, H. F.; Spears, B. K.; Springer, P. T.; Suter, L. J.; Thomas, C. A.; Town, R. P.; Vesey, R.; Weber, S. V.; Wilkens, H. L.; Wilson, D. C.

2011-05-01

154

LASIK - Laser Eye Surgery  

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Full Text Available Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During Pregnancy Computer Usage & Eye Strain Maintaining Your Sight with ... Eye Protection Eyesight Risks for Smokers Veterans & Eye Health More Lifestyle Topics > EyeSmart Tips Blood Sugar and ...

155

LASIK - Laser Eye Surgery  

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Full Text Available Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During Pregnancy Computer Usage & Eye Strain Maintaining Your Sight with ... Eye Protection Eyesight Risks for Smokers Veterans & Eye Health More Lifestyle Topics > EyeSmart Tips Opening Champagne Bottles ...

156

Landing instrument packages on regolith in micro gravity: point designs for passive, self-righting landers  

Science.gov (United States)

A small asteroid is likely to be the target of the next human exploration mission. Undoubtedly, a robotic mission will precede, whose main objective will be to characterize the target; this would have to include deployment of sensory instruments on the surface. The surface properties of small bodies are largely unknown, and this makes it essential to have detailed models for package deployment. We evaluate low cost, low risk, lander designs by considering 'pods' that have no moving parts, no guidance or thrust, that are designed to be thrown to the surface from the orbiting spacecraft. The design goal is to "encourage" the pods to land upright regardless of surface properties. With no need for guidance or articulation, these pods can be made and deployed to the surface at low cost and low risk. The challenge, of course, is to design the pods to land right-side-up, consistently, in a low gravity environment. In such an environment a body may experience cohesive forces comparable to its weight. These forces will effectively modify the physical parameters controlling a mechanical system, primarily the coefficients of friction and restitution. To make things worse, gravity will not always be pointing "down", as the presence of mass concentrations will tilt the gravity acceleration vector in unpredictable directions. We consider three point designs: (1) a weighted ellipsoidal shape, the bottom several times as dense as the top, analogous to the children's toy; (2) a pod with one side elastic and the other side inelastic; and (3) a combination of both weight distribution and material properties. We have used a discrete element model based on NVIDIA's PhysX library to design a simulation software suitable for modeling astrophysical rubble (Movshovitz, Asphaug and Korycansky, submitted). We then deploy different pod designs onto a numerical regolith testbed. Initial studies are very promising, although to date we have not included forces such as cohesion, and the effect of much smaller grain sizes than can be resolved in our simulations. We study the effect of bulk density, the velocity of deployment, and the effects of a tumbling or spinning deployment to the comet or asteroid surface. We are able to model the utility of internal actuators (vibrators, thumpers) that can rearrange or pods on the surface, or serve to embed them into a bed of loose soil. The size of the pods we are studying is ~30 cm average diameter. The key variables are shape, density distribution, and elastic properties, modeled by a coefficient of restitution. Our models benefit from asynchronous, parallel execution of the gravity module on a GPU, while the rigid-body dynamics module executes on a multi-threaded CPU for maximum performance.

Movshovitz, N.; Asphaug, E. I.

2012-12-01

157

Design Heuristics for Mapping Floating-Point Scientific Computational Kernels onto High Performance Reconfigurable Computers  

Directory of Open Access Journals (Sweden)

Full Text Available Because of the increasing need to develop efficient high-speed computational kernels, researchers have been looking at various acceleration technologies. One approach is to use field programmable gate arrays (FPGAs in conjunction with general purpose processors to form what are known as high performance reconfigurable computers (HPRCs. HPRCs have already been shown to work well for both fixed-point and integer calculations. Floating-point calculations are a different matter; obtaining speedups has been somewhat elusive. This article, after introducing the three primary HPRC development flows, takes a detailed look at “the three p’s,” which addresses the crucial relationship among performance, pipelining, and parallelism. It also examines “the FPGA design boundary,” which addresses some of the heuristics that allow developers to determine which application modules can be mapped onto the FPGAs. These ideas are illustrated by way of a simple floating-point application that is mapped onto a contemporary HPRC. This article expands upon earlier work by including details on how to map customized intellectual property cores into an HPRC environment via a hybrid development flow.

Justin L. Rice

2009-06-01

158

Design and construction of equipment for point-source, low energy electron microdosimetry measurements  

International Nuclear Information System (INIS)

Actual measurements of dose as a function of distance for point-source, discrete energy spectra are essential to the selection of radionuclides for radioimmunotherapy, as the present theoretical basis provides extrapolations into the low energy region where assumptions about the energy-loss mechanisms are believed to break down. The authors present a discussion of design criteria for an apparatus aimed at measuring dose in gases for low energy (10 to 100 keV) electron sources, as well as description of the equipment that emerged from this analysis. Given the short ranges involved, an almost-wall-less ionization chamber with cylindrical symmetry was selected. The chamber is fixed in position and a radioactive point-source is moved along its axis by remote control, preventing air disturbances in the chamber while obtaining ionization current measurements. A laser-aided positioning mechanism maintains alignment of the axis within 0.5 mm, and chamber-to-source distance is known within 0.3 mm. Special attention was given to the open-air ionization chamber design, and two different models were built. Guarding, grounding, and insulating schemes are proposed. The apparatus can be easily modified for use with gases other than air. This equipment is presently being used to provide data for validation of, or corrections to, available theoretical calculations

159

What Is Dry Eye?  

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160

Conjunctivitis: What Is Pink Eye?  

Science.gov (United States)

... Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening Guidelines Home Remedies for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye ...

 
 
 
 
161

Recognizing and Treating Eye Injuries  

Science.gov (United States)

... Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening Guidelines Home Remedies for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye ...

162

Pediatric Eye Screening Instrumentation  

Science.gov (United States)

Computational evaluations are presented for binocular eye screening using the off-axis digital retinascope. The retinascope, such as the iScreen digital screening system, has been employed to perform pediatric binocular screening using a flash lamp and single-shot camera recording. The digital images are transferred electronically to a reading center for analysis. The method has been shown to detect refractive error, amblyopia, anisocoria, and ptosis. This computational work improves the performance of the system and forms the basis for automated data analysis. For this purpose, variouis published eye models are evaluated with simulated retinascope images. Two to ten million rays are traced in each image calculation. The poster will present the simulation results for a range of eye conditions of refractive error of -20 to +20 diopters with 0.5- to-1 diopter resolution, pupil size of 3 to 8 mm diameter (1-mm increment), and staring angle of 2 to 12 degree (2-degree increment). The variation of the results with the system conditions such as the off-axis distance of light source and the shutter size of camera are also evaluated. The quantitative analysis for each eye’s and system’s condition is then performed to obtain parameters for automatic reading. The summary of the system performance is given and performance-enhancement design modifications are presented.

Chen, Ying-Ling; Lewis, J. W. L.

2001-11-01

163

Design of Neutral-Point Voltage Controller of a Three-level NPC Inverter with Small DC-Link Capacitors  

DEFF Research Database (Denmark)

A Neutral-Point-Clamped (NPC) three-level inverter with small dc-link capacitors is presented in this paper. The inverter requires zero average neutral-point current for stable neutral-point voltage. The small dc-link capacitors may not maintain capacitor voltage balance, even with zero neutral-point current. This may happen due to nonlinearities present in the circuit. This requires a fast control of the neutral-point voltage. A simple carrier based modulation strategy which allows modeling of the neutral-point voltage dynamics as a continuous function of power drawn from the inverter is proposed. This continuous model shows that the neutral-point current is proportional to the power drawn from the inverter, and it enables the use of well established classical control theory for the neutral-point voltage controller design. A simple PI (proportional integral) controller is designed for the neutral-point voltage control on the basis of the continuous model. The design method for optimum performance is discussed. The implementation of the proposed modulation strategy and the controller is very simple. The controller is implemented in a 7.5 kW induction machine based drive with only 14 ìF dc-link capacitors. Also, the experimental results show that fast and stable performance of the neutral-point voltage controller are achieved and thus verify the validity of the proposed control approach.

Maheshwari, Ram Krishan; Munk-Nielsen, Stig

2013-01-01

164

Planning proton therapy of the eye  

International Nuclear Information System (INIS)

We describe a program for planning treatments of the eye with charged particle beams. Many of its features apply to treatment planning programs in general. These include the three-dimensional definition of the tumor volume and of normal structures, the possibility of delivering the treatment beam from any direction in space, the provision of arbitrary viewpoints including a ''beam's eye'' point of view, the design and fabrication of the field shaping aperture, the specification of the necessary beam quality (range and modulation), the calculation and display of isodose contours on any plane in space and on relevant surfaces, the identification of the extent to which normal structures are included or excluded from the beam, and the simulation of the desired alignment film with which patient alignment can be verified

165

LASIK - Laser Eye Surgery  

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166

What Is Dry Eye?  

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Full Text Available ... Cataracts Contact Lens-Related Infections Detached & Torn Retina Diabetic Retinopathy Dry Eye Floaters & Flashes Glaucoma Hyperopia (Farsightedness) Low ... Is at Risk for Dry Eye? Dry Eye Diagnosis Dry Eye Treatment Sometimes people don't produce ...

167

Diabetes - Eye Complications  

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Full Text Available Diabetes - Eye Complications Introduction Patients with diabetes are more likely to have eye problems that can lead to blindness. ... prevent these eye problems from happening. How The Eye Works? Light first hits the cornea of the ...

168

What Is Dry Eye?  

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Full Text Available ... Is at Risk for Dry Eye? Dry Eye Diagnosis Dry Eye Treatment Sometimes people don't produce ... cause glare while driving at night? Featured Video Diabetes and Eye Health, presented by Dr. Robert Melendez ...

169

What Is Dry Eye?  

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Full Text Available ... to 60 Adults Over 60 Babies, Children & Teenagers Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening ... approved information from EyeSmart Related Answers Are my computer-related symptoms eye strain? Can reading harm a ...

170

Conjunctivitis (Pink Eye)  

Science.gov (United States)

... of publications and references used throughout site. Conjunctivitis (Pink Eye) One Page Overview Pink, itchy eyes? Conjunctivitis ... eyes Crusting of eyelids or lashes sometimes occurs Pink Eye: What To Do Discusses causes and treatment, ...

171

Design of multi-point automatic positioning pre-programmed crane control system  

International Nuclear Information System (INIS)

This automatic positioning system is designed for the crane which is in common use. The crane hall is cut into several parts, the position is detected by the photoelectric switches, and the PLC and inverter are used for the control devices. The automatic positioning control of the crane is completed by means of the timing movement. The positioning error is less than 2.1 cm, the swing range when lifting object is less than 5.7 cm, and the average speed of the crane is more than 90% of the rated speed. This paper gives further description in the positioning control, direction control, speed control and the identification of the starting point. Finally it gives an analysis of the automatic positioning performance. (authors)

172

Design of the Point Absorber Wave Energy Converter for Assaluyeh Port  

Directory of Open Access Journals (Sweden)

Full Text Available The research explained in this paper was carried out to analyze and design a point absorber waveenergy convertor for Assaluyeh coastal on Persian Gulf. The geographical conditions of this region have some local short waves which may be ideal to use this type of energy convertor. According to the collecting of wave data and using an optimized buoy, it is concluded that the adjustments on damping and natural frequency have more effect on average heave displacement. Therefore, by changing the shape of flat buoy to conical cylindrical, the drag coefficient that has direct effect on the damping of the buoy could be reduced. Regarding the length to diameter ratio of 1.7 for the selected buoy, changing its shape from flat cylinder to conical cylinder causes the drag coefficient to decrease by 50 %, which is followed by 20% increase in average amplitude of heave motion from

Mehdi Nazari

2013-01-01

173

Global Machine Design and Double X-point Equilibrium Configurations for Ignitor*  

Science.gov (United States)

The detailed design of the Ignitor machine has been carried out by considering extended limiter plasma configurations that are up-down symmetric and whose outer magnetic surfaces follow closely the cavity of the toroidal magnet over most of the vertical cross section. This provision minimizes the out-of- plane forces produced by the plasma current and acting on the toroidal magnet. When, instead, the adopted plasma equilibrium configuration is of the double X-point type the out-of-plane forces increase, and a complete structural analysis to take this increase into account becomes appropriate. The reference maximum plasma current Ip, in order to maintain an acceptable magnetic safety factor, is reduced from 11 MA in the extended limiter to 9 MA in the double X-point configuration while the magnetic field on axis (R01.32 m) is maintained at BT13 T. The reduced scenario involving Ip6 MA and BT9 T does not present a problem. Both 3D and 2D drawings of each individual machine component are produced using the Dassault Systems CATIA-V software. After their integration into a single 3D CATIA model of the Core (Load Assembly), the electro-fluidic and fluidic lines which supply electrical currents and helium cooling gas to the coils are included and mechanically connected to the main machine components.^*Sponsored in part by ENEA of Italy and by the U.S. D.O.E.

Bianchi, A.; Parodi, B.; Coppi, B.

2008-11-01

174

From Takeoff to Landing: Looking at the Design Process for the Development of NASA Blast at Thanksgiving Point  

Directory of Open Access Journals (Sweden)

Full Text Available In this article we discuss the process of design used to develop and design the NASA Blast exhibition at Thanksgiving Point, a museum complex in Lehi, Utah. This was a class project for the Advanced Instructional Design Class at Brigham Young University. In an attempt to create a new discourse (Krippendorff, 2006 for Thanksgiving Point visitors and staff members, the design class used a very fluid design approach by utilizing brainstorming, researching, class member personas, and prototyping to create ideas for the new exhibition. Because of the nature of the experience, the design class developed their own techniques to enhance the process of their design. The result of the design was a compelling narrative that brought all the elements of the exhibition together in a cohesive piece.

Stephen Ashton

2011-01-01

175

Foreign Body in Eye  

Science.gov (United States)

Foreign Body in Eye Foreign Body in Eye htmForeignBodyEye Eyelashes prevent most particles or objects from entering the eye, and tears usually are able to ... embed itself below the surface of the eye. Foreign bodies in the eye can be small specks ...

176

Point design for deuterium-deuterium compact reversed-field pinch reactors  

International Nuclear Information System (INIS)

A deuterium-deuterium (D-D) reversed-field pinch (RFP) reactor may be made comparable in size and cost to a deuterium-tritium (D-T) reactor at the expense of high-thermal heat load to the first wall. This heat load is the result of the larger percentage of fusion power in charged particles in the D-D reaction as compared to the D-T reaction. The heat load may be reduced by increasing the reactor size and hence the cost. In addition to this ''degraded'' design, the size may be kept small by means of a higher heat load wall, or by means of a toroidal divertor, in which case most of the heat load seen by the wall is in the form of radiation. Point designs are developed for these approaches and cost studies are performed and compared with a D-T reactor. The results indicate that the cost of electricity of a D-D RFP reactor is about20% higher than a D-T RFP reactor. This increased cost could be offset by the inherent safety features of the D-D fuel cycle

177

Design characteristics and point-spread function evaluation of bifocal intraocular lenses  

Science.gov (United States)

Lens extraction during cataract operation has mainly two consequences: first, a reduction of the refractive power of the eye and second, the loss of accommodation. Insertion of a monofocal intraocular lens counterbalances the first effect, accommodation, however, remains lost. Various types of intraocular lenses exhibiting two different focal lengths (bifocal) are at present under clinical trial. With such lenses one focal length corresponds to the far vision (P.) while the other is related to the near vision (P )(Fig. 1). In both cases, however, two images are formed simultaneously in the eye: one is focused on the retina while the other is out of focus. First clinical results indicate that a satisfactory situation can be obtained both in far and near vision.

Rol, Pascal O.

1991-06-01

178

Point- To- Point Protocol  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The telephone line provides a physical link, but to control and manage the transfer of data, there is a need for point-to-point connection. The first protocol devised for this purpose was serial line internet protocol (SLIP). However, SLIP has some deficiencies: it does not support protocols other than internet protocol (IP). It does not allow the IP addresses to be assigned dynamically, and it does not support authentication of the user. The POINT-TO-POINT (PPP) is a protocol designed to res...

Immadisetty L V Chandrika,; Venkata Videhi Balusupati,; A.Rama Krishna,

2012-01-01

179

Formation of the hurricane eye  

Science.gov (United States)

This dissertation consists of three distinct studies which investigate aspects of eye formation. The first study reviews eye phenomenon in a variety of vortices ranging from simple vortices to the menagerie of geophysical vortices, emphasizing similarities and differences to the eyes formed in hurricanes. The hurricane eye is found to be a paradoxical structure imposed by conservation of angular momentum and the boundaries of the vortex. A comprehensive definition for hurricane eye formation is proposed and various eye formation mechanisms are summarized. The next study presents a simple theoretical argument to isolate the conditions under which a tropical cyclone can rapidly develop a warm-core thermal structure and subsequently approach a steady state. The theoretical argument is based on the balanced vortex model and, in particular, on the associated transverse circulation equation and the geopotential tendency equation. The transverse circulation and the temperature tendency in a tropical vortex depend not only on the diabatic forcing, but also on the spatial distributions of the static stability, the baroclinity, and the inertial stability. The vortex response to diabatic heating depends critically on whether the heating occurs in the low inertial stability region outside the radius of maximum wind or in the high inertial stability region inside the radius of maximum wind. This result suggests that rapid intensification is favored for storms which have at least some of the eyewall convection inside the radius of maximum wind. The development of an eye partially removes diabatic heating from the high inertial stability region of the storm center, yet rapid intensification may continue if the eyewall heating continues to become more efficient. As the warm core matures and static stability increases over the inner core, conditions there become less favorable for deep upright convection and the storm tends to approach a steady state. The final study characterizes the kinematic and thermodynamic changes that occur before, during, and after the initial eye formations of a broad set of Atlantic tropical cyclones. To obtain the requisite structure and intensity parameters, a new data set has been synthesized from the Vortex Data Messages transmitted by routine aircraft reconnaissance from 1989--2008. Intensity ranges are determined for the times when the eye/eyewall structure first appears in aircraft radar and infrared satellite imagery. The mean intensity at which an eye is first observed in both aircraft or satellite imagery is found to be 58 kt, somewhat lower than reported in previous studies. Changes about the time of eye formation are examined for intensity, the radius of maximum winds, the minimum Rossby radius of deformation, eye temperature and dew point temperature depression. Storms are found to intensify most rapidly near the time of eye formation, especially when a persistent eye is observed in infrared satellite imagery. Many storms which are forming eyes are found to undergo a substantial and rapid contraction in the radius of maximum winds during the 24-h period before the eye is observed; once the eye is present, this contraction slows or ceases. Strong warming at lower levels (850 or 700 hPa) of the eye is not observed to correlate well with the time in which the eye is first observed. Finally, observations suggest that the dynamical heating efficiency of the resulting eyewall increases even as the physical scale of the efficient heating region decreases. This allows the storm to continue intensifying even though the total inner core diabatic heating may decrease. The answer to why some storms fail to form eyes may shed light on whether eye formation is a stochastic process involving constructive and destructive mesoscale interactions---or whether it is a manifold attractor of the system sometimes stymied by an unfavorable environment.

Vigh, Jonathan L.

180

Preliminary fly's eye results  

International Nuclear Information System (INIS)

We describe an ultra-high energy physics observatory, the Fly's Eye, designed to measure extensive air showers (EAS) in the energy range 1017-1021eV via atmospheric fluorescence. Preliminary results are presented for the following measurements: (1) limits on the extragalactic neutrino flux at 1020eV, (2) the high energy cosmic ray spectrum, (3) sources of high energy cosmic rays, (4) the total proton cross section ?sub(pp)

 
 
 
 
181

Teaching Skills to Use a Computer Mouse in Preschoolers with Developmental Disabilities: Shaping Moving a Mouse and Eye-Hand Coordination  

Science.gov (United States)

We taught seven preschoolers with developmental disabilities to point-and-click with a computer mouse. The computer-based training program consisted of three parts, based on a task analysis of the behavioral prerequisites to point-and-click. Training 1 was designed to shape moving the mouse. Training 2 was designed to build eye-hand coordination…

Shimizu, Hirofumi; Yoon, Soyoung; McDonough, Christopher S.

2010-01-01

182

Design and Development of Intracavity Optical Parametric Oscillator-based Eye Safe Laser Operating at 20 Hz without Forced Air Cooling  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we report\tthe design and development of an electro-optically\tQ-switched diode\tpumped\tNd:YAG\tlaser with intracavity optical parametric oscillator, generating ~ 5 ns laser pulses of ~8 mJ energy at eye safe wavelength of 1534 nm. A\tZ-shaped laser resonator has\tbeen designed with porro prism\tend\treflector in Q-switch arm containing\tRTP\tQ-Switch\tand\ta suitably oriented waveplate. The gain arm consists of a Ø3\tx 72\tmm\tNd:\tYAG laser\trod,\tpumped\tfrom\tone\tside\tby 3\tx 5 bar laser diode array stack\temitting\ttotal\toptical peak\tpower of\t740\tW at 804 nm at 38 °C. Thermoelectric coolers (TECs have been employed to maintain the optimum temperature of laser diode arrays and the combined heat load from the pump chamber and TECs is distributed over the system base plate with embedded\theat\tpipes. Such cooling mechanism\thas\teliminated the requirement\tof fins and fans in\tthe laser\tsystem.\tEye\tsafe\tradiation\tis out-coupled through\tintra\tcavity KTA OPO\t(5 x\t5\tx 20\tmm3 placed in the gain arm. Laser was operated at 20 Hz for several duty cycles of 10 min on and 10 min off and output energy remained\tstable\twithin\t±0.5\tmJ\twithout\tany\tforced\tair/liquid\tcooling.

Atul\tBhardwaj

2013-11-01

183

Screening of Adolescents for Eye Diseases in Nigerian High Schools  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effectiveness of pre-entrance eye screening programmes for school age children is still controversial. A point prevalence study of high school adolescents was conducted to determine the magnitude of undiagnosed eye diseases and offer appropriate treatment where feasible.

Adegbehingbe, Bo; Oladehinde, Mk; Majemgbasan, To; Onakpoya, Ho; Osagiede, Eo

2005-01-01

184

Design and Implementation of Numerical Linear Algebra Algorithms on Fixed Point DSPs  

Directory of Open Access Journals (Sweden)

Full Text Available Numerical linear algebra algorithms use the inherent elegance of matrix formulations and are usually implemented using C/C++ floating point representation. The system implementation is faced with practical constraints because these algorithms usually need to run in real time on fixed point digital signal processors (DSPs to reduce total hardware costs. Converting the simulation model to fixed point arithmetic and then porting it to a target DSP device is a difficult and time-consuming process. In this paper, we analyze the conversion process. We transformed selected linear algebra algorithms from floating point to fixed point arithmetic, and compared real-time requirements and performance between the fixed point DSP and floating point DSP algorithm implementations. We also introduce an advanced code optimization and an implementation by DSP-specific, fixed point C code generation. By using the techniques described in the paper, speed can be increased by a factor of up to 10 compared to floating point emulation on fixed point hardware.

Gene Frantz

2007-01-01

185

What Is Dry Eye?  

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186

What Is Dry Eye?  

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187

Design of Multi-point Wireless Temperature and Humidity Sensor Network Based on NRF24l01  

Directory of Open Access Journals (Sweden)

Full Text Available Many fields need to use the multi-point data acquisition and transmission system to overcome the weakness of wired data transmission system. Based on the single chip transceiver nRF24L01 and favorite microprocessor STM32F107, designed the multi-point wireless sensor network. The system used the 1-wire temperature and humidity sensor DHT22 as Data acquisition components. The paper studied the hardware construction and the software design in details. Designed the circuit diagram, made the PCB plate, programmed software by Keil C and debugged with Keil uVision4 MDK V4.10. Results show that, the multi-point wireless sensor network can work more efficiently and more flexibility. It meets the performance requirements of high real-time, low power consumption and low cost.

Jin Gang

2013-01-01

188

Design of a Floating-Point Fused Add-Subtract Unit Using Verilog  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A floating-point (FP) fused add-subtract unit is presented that performs simultaneous floating-point operation of add-subtract on a common pair of single-precision data at the same time that it takes to perform in a single addition with a conventional floating-point adder. The system was placed and routed in 45nm process so that there will be less consumption of memory as well as power.

Mayank Sharma,; Prince Nagar,; Ghanshyam Kumar Singh; Ram Mohan Mehra

2013-01-01

189

Design of a Floating-Point Fused Add-Subtract Unit Using Verilog  

Directory of Open Access Journals (Sweden)

Full Text Available A floating-point (FP fused add-subtract unit is presented that performs simultaneous floating-point operation of add-subtract on a common pair of single-precision data at the same time that it takes to perform in a single addition with a conventional floating-point adder. The system was placed and routed in 45nm process so that there will be less consumption of memory as well as power.

Mayank Sharma,

2013-06-01

190

Design of FPGA based 32-bit Floating Point Arithmetic Unit and verification of its VHDL code using MATLAB  

Directory of Open Access Journals (Sweden)

Full Text Available Most of the algorithms implemented in FPGAs used to be fixed-point. Floating-point operations are useful for computations involving large dynamic range, but they require significantly more resources than integer operations. With the current trends in system requirements and available FPGAs, floating-point implementations are becoming more common and designers are increasingly taking advantage of FPGAs as a platform for floating-point implementations. The rapid advance in Field-Programmable Gate Array (FPGA technology makes such devices increasingly attractive for implementing floating-point arithmetic. Compared to Application Specific Integrated Circuits, FPGAs offer reduced development time and costs. Moreover, their flexibility enables field upgrade and adaptation of hardware to run-time conditions. A 32 bit floating point arithmetic unit with IEEE 754 Standard has been designed using VHDL code and all operations of addition, subtraction, multiplication and division are tested on Xilinx. Thereafter, Simulink model in MAT lab has been created for verification of VHDL code of that Floating Point Arithmetic Unit in Modelsim.

Naresh Grover

2014-02-01

191

Design and development of a low-cost eye tracking system for the rehabilitation of the completely locked-in patient.  

Science.gov (United States)

This article describes the design and development process of an eye tracking-based computer system that benefits from the intact ocular motor control of the completely locked-in patient to provide him or her with an alternative means of communication. A completely locked-in patient is an individual who has lost all types of motor control and communication ability with people in his or her environment. This developed system uses a head-mounted web camera to capture real-time images of the patient's eye. These images are then passed to a program, developed using Matlab, which processes them and computes the coordinates of the pupil position. The program then sends commands to an interactive JAVA-based interface, which provides the patient with a matrix of pictograms representing the most essential daily communication activities. When a pictogram is activated (clicked), the system plays back an audible statement, recorded in any language, reflecting the desired activity. Ten healthy adult volunteers, free from any musculoskeletal or neurological disorders, participated in the validation of the system. Validation results revealed a system accuracy of 96.11+/-5.58 % and repeatability of 94.44+/-2.51 %. The rehabilitative system developed in this project offers the locked-in patient, of any social class, the ability of simple yet effective communication. The advantages of this system over existing systems are low cost, low processing power, ease of operation, little training requirements, minimal disturbance to the patient, and ease of customization to any mother tongue. PMID:17946657

Abu-Faraj, Ziad O; Mashaalany, Maya J; Sleiman, Habib C Bou; Heneine, Jean-Louis D; Al Katergi, Waleed M

2006-01-01

192

LASIK - Laser Eye Surgery  

Science.gov (United States)

... the battery and always wear safety goggles. Eye Makeup Throw out eye makeup after three months to prevent infection. If you get an eye infection, replace makeup immediately. "No Rub" a No Go To prevent ...

193

What Is Dry Eye?  

Medline Plus

Full Text Available ... Low Vision Myopia (Nearsightedness) Pink Eye (Conjunctivitis) Presbyopia (Aging Eye) Stye Uveitis/Iritis See all Diseases & Conditions > ... right quality of tears to keep their eyes healthy and comfortable. This condition is known as dry ...

194

What Is Dry Eye?  

Medline Plus

Full Text Available ... Related Resources Related Topics Six Smart Things College Students Should Do For Their Eyes - Eye M.D.- ... Resources EyeWiki contact us sitemap Reproducing text or images from this website is strictly prohibited by US ...

195

What Is Dry Eye?  

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Full Text Available ... to 60 Adults Over 60 Babies, Children & Teenagers Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening ... contact lenses if I have drusen? Are my computer-related symptoms eye strain? Featured Video Diabetes and ...

196

Eye Injuries in Sports  

Science.gov (United States)

... eye. Blunt trauma causes most sports-related eye injuries. Some serious examples are an orbital blowout fracture (a broken ... eye") looks bad but usually is a less serious injury. Penetrating injuries occur when something cuts into your ...

197

What Is Dry Eye?  

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Full Text Available ... to 60 Adults Over 60 Babies, Children & Teenagers Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening ... people don't produce enough tears or the right quality of tears to keep their eyes healthy ...

198

Diabetes - Eye Complications  

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Full Text Available ... diabetes are more likely to develop eye problems. Insulin dependent patients are more likely to have eye problems than patients who are not insulin dependent. Doctors cannot predict who will have eye ...

199

What Is Dry Eye?  

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Full Text Available ... Adults Over 60 Babies, Children & Teenagers Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening Guidelines Home ... cause glare while driving at night? Featured Video Diabetes and Eye Health, presented by Dr. Robert Melendez ...

200

What Is Dry Eye?  

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Full Text Available ... Bacterial Keratitis Bell's Palsy Blepharitis Cataracts Contact Lens-Related Infections Detached & Torn Retina Diabetic Retinopathy Dry Eye Floaters & Flashes Glaucoma Hyperopia (Farsightedness) Low Vision Myopia (Nearsightedness) Pink Eye (Conjunctivitis) Presbyopia (Aging Eye) ...

 
 
 
 
201

Diabetes - Eye Complications  

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Full Text Available Diabetes - Eye Complications Introduction Patients with diabetes are more likely to have eye problems that can lead to blindness. Many of these eye diseases can be prevented or delayed ...

202

What Is Dry Eye?  

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Full Text Available ... the eyelids, cleanses the eye and washes away foreign particles or irritants. The inner layer consists of ... response to eye irritation or emotion. When a foreign body or dryness irritates the eye, or when ...

203

What Is Dry Eye?  

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Full Text Available ... By producing tears at a slow and steady rate, the eye stays moist and comfortable. The eye ... It can make tears at a slow, steady rate to maintain normal eye lubrication. It can also ...

204

LASIK - Laser Eye Surgery  

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Full Text Available ... risky activities. Jumping a Battery Take precautions to prevent eye injury. Never lean over the battery and ... Throw out eye makeup after three months to prevent infection. If you get an eye infection, replace ...

205

Pink Eye (Conjunctivitis)  

Science.gov (United States)

newsletter | contact Share | Pink Eye (Conjunctivitis) Information for adults A A A This is the most typical appearance of conjunctivitis with redness of ... eye and mucoid debris on the eyelashes. Overview Pink eye (conjunctivitis) is an inflammation of the tissue ...

206

Kinematics of visually-guided eye movements.  

Science.gov (United States)

One of the hallmarks of an eye movement that follows Listing's law is the half-angle rule that says that the angular velocity of the eye tilts by half the angle of eccentricity of the line of sight relative to primary eye position. Since all visually-guided eye movements in the regime of far viewing follow Listing's law (with the head still and upright), the question about its origin is of considerable importance. Here, we provide theoretical and experimental evidence that Listing's law results from a unique motor strategy that allows minimizing ocular torsion while smoothly tracking objects of interest along any path in visual space. The strategy consists in compounding conventional ocular rotations in meridian planes, that is in horizontal, vertical and oblique directions (which are all torsion-free) with small linear displacements of the eye in the frontal plane. Such compound rotation-displacements of the eye can explain the kinematic paradox that the fixation point may rotate in one plane while the eye rotates in other planes. Its unique signature is the half-angle law in the position domain, which means that the rotation plane of the eye tilts by half-the angle of gaze eccentricity. We show that this law does not readily generalize to the velocity domain of visually-guided eye movements because the angular eye velocity is the sum of two terms, one associated with rotations in meridian planes and one associated with displacements of the eye in the frontal plane. While the first term does not depend on eye position the second term does depend on eye position. We show that compounded rotation - displacements perfectly predict the average smooth kinematics of the eye during steady- state pursuit in both the position and velocity domain. PMID:24751602

Hess, Bernhard J M; Thomassen, Jakob S

2014-01-01

207

Point- To- Point Protocol  

Directory of Open Access Journals (Sweden)

Full Text Available The telephone line provides a physical link, but to control and manage the transfer of data, there is a need for point-to-point connection. The first protocol devised for this purpose was serial line internet protocol (SLIP. However, SLIP has some deficiencies: it does not support protocols other than internet protocol (IP. It does not allow the IP addresses to be assigned dynamically, and it does not support authentication of the user. The POINT-TO-POINT (PPP is a protocol designed to respond to respond to the deficiencies. Today the PPP protocol standard finds wide use in asynchronous and synchronous connections between computers, bridges, routers and other intermediate devices.PPP is gaining acceptance as a standard for Integrated Services Digital Network(ISDN, and many implementations of X.25 also support PPP connection.

Immadisetty L V Chandrika,

2012-11-01

208

Sensitivity of Design Optimality Criteria to Second-order Response SurfaceModel Restrictions and Center Point Replications  

Directory of Open Access Journals (Sweden)

Full Text Available

Abstract In this work, we investigate the role of several model characteristics and center point replications on the properties of A-, D-, G-, and IV- optimality for four –factor second-order response surface design. It was discovered that A-, D-, and G- efficiencies tend to reduce as the center points are replicated while the effect on scaled average prediction variance tends to be very insignificant. Among the restricted models considered, the pure linear model (model1 turns out to be the best in terms of quality of estimation and model prediction.

Key words: Design optimality criteria; Center point replications; Response surface methodology

Angela U. Chukwu

2012-02-01

209

The ARIES-III D-3He tokamak reactor: Design-point determination and parametric studies  

International Nuclear Information System (INIS)

The multi-institutional ARIES study has generated a conceptual design of another tokamak fusion reactor in a series that varies the assumed advances in technology and physics. The ARIES-3 design uses a D-3He fuel cycle and requires advances in technology and physics for economical attractiveness. The optimal design was characterized through systems analyses for eventual conceptual engineering design. Results from the systems analysis are summarized, and a comparison with the high-field, D-T fueled ARIES-1 is included. 11 refs., 5 figs

210

Design of piping fixed points in the thorium high-temperature reactor (THTR)  

International Nuclear Information System (INIS)

The boundary conditions of fixed-point construction in the pipelines of the THTR, Hamm-Uentrop, are discussed. Particular regard was paid to the loads on the headers and their supports. For the case of transverse fracture, the loads on the supports and on the header were determined using a single-mass resonator model. Three different points of rupture were assumed. For the case of longitudinal fracture, the calculation of support loads and header loads is explained, and the support loads and maximum bending moments are presented in a diagram as a function of time. (orig.)

211

Eating for Your Eyes  

Science.gov (United States)

An educational program targeting older adults was developed to increase knowledge regarding nutrition and eye health. With age, the chance for eye disease increases, so prevention is critical. The Eating for Your Eyes program has promoted behavior changes regarding eye health among the participants. This program is easily replicated and use is…

Stastny, Sherri Nordstrom; Garden-Robinson, Julie

2011-01-01

212

Orbit Transfer Vehicle (OTV) advanced expander cycle engine point design study. Task 7: Engine data summary  

Science.gov (United States)

A performance optimized engine system design for a man-rated advanced LOX/hydrogen expander cycle engine was investigated. The data are presented in tables, figures, and drawings. The following categories of data for the advanced expander cycle engine are presented: engine operating specification and pressure schedule; engine system layout drawing; major component layout drawings, including thrust chamber and nozzle, extendible nozzle actuating mechanism and seal, LOX turbopump, LOX boost pump, hydrogen turbopump, hydrogen boost pump, and propellant control valves; engine performance and service life prediction; engine weight; and engine envelope. The data represent updates based upon current results from the design and analyses tasks performed under contract. Futher iterations in the designs and data can be expected as the advanced expander cycle engine design matures.

Christensen, K. L.

1980-01-01

213

Orbit Transfer Vehicle (OTV) advanced expander cycle engine point design study. Volume 2: Study results  

Science.gov (United States)

Detailed computer models of the engine were developed to predict both the steady state and transient operation of the engine system. Mechanical design layout drawings were prepared for the following components: thrust chamber and nozzle; extendible nozzle actuating mechanism and seal; LOX turbopump and boost pump; hydrogen turbopump and boost pump; and the propellant control valves. The necessary heat transfer, stress, fluid flow, dynamic, and performance analyses were performed to support the mechanical design.

1980-01-01

214

Design and Evaluation of Cell Phone Pointing Interface for Robot Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work a pointing interface based on human gestures using a mobile phone accelerometer for interaction with robots is proposed. Through this interface the user can sketch stroke gestures on a computer screen using the cell phone accelerometer to make a selection and instruct a robot to perform a task. Selection, cancelation and movement, as well as some additional commands such as stop, pause and resume are supported. All the projected gestures are processed using known image analysis a...

Saso Koceski; Natasa Koceska; Ivica Kocev

2012-01-01

215

Implications for the inter-organizational design of environmental care when changing environmental control points  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper we try to bridge the gap between two lines of thought within the environmental care literature. We differentiate between two major clusters in this literature; (1) environmental management and (2) strategic approach to environmental care. Although both approaches focus on the same object i.e. management of environmental care, the two bodies of knowledge apply different starting points. The first one focuses on the physical material flow and effects, the second approach starts wi...

Hagelaar, J. L. F.; Seuring, S.

2006-01-01

216

Design of state-feedback controllers including sensitivity reduction, with applications to precision pointing  

Science.gov (United States)

The design procedure of feedback controllers was described and the considerations for the selection of the design parameters were given. The frequency domain properties of single-input single-output systems using state feedback controllers are analyzed, and desirable phase and gain margin properties are demonstrated. Special consideration is given to the design of controllers for tracking systems, especially those designed to track polynomial commands. As an example, a controller was designed for a tracking telescope with a polynomial tracking requirement and some special features such as actuator saturation and multiple measurements, one of which is sampled. The resulting system has a tracking performance comparing favorably with a much more complicated digital aided tracker. The parameter sensitivity reduction was treated by considering the variable parameters as random variables. A performance index is defined as a weighted sum of the state and control convariances that sum from both the random system disturbances and the parameter uncertainties, and is minimized numerically by adjusting a set of free parameters.

Hadass, Z.

1974-01-01

217

A conceptual design study of point focusing thin-film solar concentrators  

Science.gov (United States)

Candidates for reflector panel design concepts, including materials and configurations, were identified. The large list of candidates was screened and reduced to the five most promising ones. Cost and technical factors were used in making the final choices for the panel conceptual design, which was a stiffened steel skin substrate with a bonded, acrylic overcoated, aluminized polyester film reflective surface. Computer simulations were run for the concentrator optics using the selected panel design, and experimentally determined specularity and reflectivity values. Intercept factor curves and energy to the aperture curves were produced. These curves indicate that surface errors of 2 mrad (milliradians) or less would be required to capture the desired energy for a Brayton cycle 816 C case. Two test panels were fabricated to demonstrate manufacturability and optically tested for surface error. Surface errors in the range of 1.75 mrad and 2.2 mrad were measured.

1981-11-01

218

Orbit Transfer Vehicle (OTV) advanced expander cycle engine point design study. Volume 1: Executive summary  

Science.gov (United States)

The objective of the study was to generate the system design of a performance-optimized, advanced LOX/hydrogen expander cycle space engine. The engine requirements are summarized, and the development and operational experience with the expander cycle RL10 engine were reviewed. The engine development program is outlined.

1981-01-01

219

Orbital Transfer Vehicle (OTV) advanced expander cycle engine point design study  

Science.gov (United States)

Progress in the development of a performance optimized engine system design for an advanced LOX/hydrogen expander cycle engine is reported. Analysis of the components and engine and the resulting drawings is discussed. The status of the orbit transfer vehicle liquid engine transient simulation computer model is given.

Mellish, J. A.

1980-01-01

220

Lenses matching of compound eye for target positioning  

Science.gov (United States)

Compound eye, as a new imaging method with multi-lens for a large field of view, could complete target positioning and detection fastly, especially at close range. Therefore it could be applicated in the fields of military and medical treatment and aviation with vast market potential and development prospect. Yet the compound eye imaging method designed use three layer construction of multiple lens array arranged in a curved surface and refractive lens and imaging sensor of CMOS. In order to simplify process structure and increase the imaging area of every sub-eye, the imaging area of every eye is coved with the whole CMOS. Therefore, for several imaging point of one target, the corresponding lens of every imaging point is unkonown, and thus to identify. So an algorithm was put forward. Firstly, according to the Regular Geometry relationship of several adjacent lenses, data organization of seven lenses with a main lens was built. Subsequently, by the data organization, when one target was caught by several unknown lenses, we search every combined type of the received lenses. And for every combined type, two lenses were selected to combine and were used to calculate one three-dimensional (3D) coordinate of the target. If the 3D coordinates are same to the some combine type of the lenses numbers, in theory, the lenses and the imaging points are matched. So according to error of the 3D coordinates is calculated by the different seven lenses numbers combines, the unknown lenses could be distinguished. The experimental results show that the presented algorithm is feasible and can complete matching task for imaging points and corresponding lenses.

Guo, Fang; Zheng, Yan Pei; Wang, Keyi

2012-10-01

 
 
 
 
221

Mechanical design considerations for a 3m class fast pointing telescope  

Science.gov (United States)

A number of scientific observations take advantage of the use of robotic, fast pointing telescopes; in particular, fast reacting small telescopes were especially useful for gamma ray burst follow-up which now require better performances and greater telescope size. However, increasing telescope size could imply some limitations in terms of operability and technological solutions. In order to select the best telescope configuration it is necessary to take into account mechanical set up, pointing strategy, wind effects and the resulting effective costs. This paper will investigate and compare the characteristics of traditional alt-az and alt-alt telescope configurations considering also an innovative alt-alt set up to be developed as an alternative to the mainstream layout of present medium class telescopes. In the alt-alt case the system exploits the heritage of larger telescope projects like LBT, coupled with a more traditional fork mounted to match the alt-alt kinematics, so obtaining a more stable machine and minimizing the blind spot limitation.

Riva, M.; Bortoletto, F.; Bonoli, C.; de Caprio, V.; Spanó, P.; Covino, S.; Molinari, E.; Vitali, F.; Zannoni, M.; Chincarini, G.

2010-07-01

222

Towards a systematic design of isotropic bulk magnetic metamaterials using the cubic point groups of symmetry  

CERN Document Server

In this paper a systematic approach to the design of bulk isotropic magnetic metamaterials is presented. The role of the symmetries of both the constitutive element and the lattice are analyzed. For this purpose it is assumed that the metamaterial is composed by cubic SRR resonators, arranged in a cubic lattice. The minimum symmetries needed to ensure an isotropic behavior are analyzed, and some particular configurations are proposed. Besides, an equivalent circuit model is proposed for the considered cubic SRR resonators. Experiments are carried out in order to validate the proposed theory. We hope that this analysis will pave the way to the design of bulk metamaterials with strong isotropic magnetic response, including negative permeability and left-handed metamaterials.

Baena, J D; Marques, R

2007-01-01

223

New pediatric vision screener employing polarization-modulated, retinal-birefringence-scanning-based strabismus detection and bull's eye focus detection with an improved target system: opto-mechanical design and operation  

Science.gov (United States)

Amblyopia ("lazy eye") is a major public health problem, caused by misalignment of the eyes (strabismus) or defocus. If detected early in childhood, there is an excellent response to therapy, yet most children are detected too late to be treated effectively. Commercially available vision screening devices that test for amblyopia's primary causes can detect strabismus only indirectly and inaccurately via assessment of the positions of external light reflections from the cornea, but they cannot detect the anatomical feature of the eyes where fixation actually occurs (the fovea). Our laboratory has been developing technology to detect true foveal fixation, by exploiting the birefringence of the uniquely arranged Henle fibers delineating the fovea using retinal birefringence scanning (RBS), and we recently described a polarization-modulated approach to RBS that enables entirely direct and reliable detection of true foveal fixation, with greatly enhanced signal-to-noise ratio and essentially independent of corneal birefringence (a confounding variable with all polarization-sensitive ophthalmic technology). Here, we describe the design and operation of a new pediatric vision screener that employs polarization-modulated, RBS-based strabismus detection and bull's eye focus detection with an improved target system, and demonstrate the feasibility of this new approach.

Irsch, Kristina; Gramatikov, Boris I.; Wu, Yi-Kai; Guyton, David L.

2014-06-01

224

Deployment Design of Wireless Sensor Network for Simple Multi-Point Surveillance of a Moving Target  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we focus on the problem of tracking a moving target in a wireless sensor network (WSN, in which the capability of each sensor is relatively limited, to construct large-scale WSNs at a reasonable cost. We first propose two simple multi-point surveillance schemes for a moving target in a WSN and demonstrate that one of the schemes can achieve high tracking probability with low power consumption. In addition, we examine the relationship between tracking probability and sensor density through simulations, and then derive an approximate expression representing the relationship. As the results, we present guidelines for sensor density, tracking probability, and the number of monitoring sensors that satisfy a variety of application demands.

Yuji Oie

2009-05-01

225

New design and analysis for point-focusing of surface waves in contact testing.  

Science.gov (United States)

A method was presented for the intensive focusing of surface ultrasonic waves in contact testing, and an ultrasonic contact transducer was fabricated and characterized. The acoustic contact lens of the transducer was in a shape which was obtained by rotating a right-angled triangle having a critical angle for the generation of surface waves. PVDF film was employed as an ultrasonic transmitter and receiver. The fabricated transducer showed the focusing feature of a narrow lateral half width and high sound intensity at a focal point. Also, a simple model was presented to estimate theoretically the stress pattern on a symmetry axis of the transducer. The stress pattern predicted using the model showed good agreement with the experimental result. This concept can also be used in acoustic microscopy. PMID:18263170

Kim, B G; Lee, J O; Lee, S

1993-01-01

226

Design and Evaluation of Cell Phone Pointing Interface for Robot Control  

Directory of Open Access Journals (Sweden)

Full Text Available In this work a pointing interface based on human gestures using a mobile phone accelerometer for interaction with robots is proposed. Through this interface the user can sketch stroke gestures on a computer screen using the cell phone accelerometer to make a selection and instruct a robot to perform a task. Selection, cancelation and movement, as well as some additional commands such as stop, pause and resume are supported. All the projected gestures are processed using known image analysis algorithms providing instantaneous position and path information. The proposed interface is experimentally evaluated and the results show that it is efficient, natural, robust and easy to use. It also provides asynchronous robot control with minimum operator effort and engagement.

Saso Koceski

2012-10-01

227

Robot design from a neuro-ethological point of view. Shinkei kodogaku kara mita robot  

Energy Technology Data Exchange (ETDEWEB)

The science concerning the method of obtaining the desirable information by adjusting the controllable quantity based on the measurement of the uncontrollable quantity is called cybernetics. The cybernetics is the most ideal image of the robot. The instinct of animals is supported by the nervous system. The science which deals with the nervous system of animals as a function of its instinct is called the neuro-ethology. In this sense, the neuro-ethology is identical to the cybernetics. The fundamental basis of robot design the design of the robot is therefore the neuro-ethology. The treatment of the dependent information about space and time in the auditory nervous system of animals was reviewed. The petuliarity of the auditory system, auditory as an interferometry, and the evolution of the auditory system was explained by taking the sonner system in bats as a prototype of the auditory system of animal. For further explanation of auditory system, the correspondence to the phonetic recognition of Homo-sapiens was also reviewed. It is important for design of the robot to investigate the mechanism to extract informations of the auditory nervous system in animals including Homo-sapiens. 19 refs., 10 figs.

Shimozawa, T. (Hokkaido Univ., Sapporo (Japan). Research Inst. of Applied Electricity)

1991-11-01

228

Contribution to the design of a micro-programmed floating point arithmetical operator  

International Nuclear Information System (INIS)

This report is intended for a presentation of the implementation of an arithmetical operator. Fast microprocessor together with microprogramming techniques were used for development. For clarity, this report is shared in three parts following the different steps of design and development. The first part relates the preliminary study stage, setting down the outlines of the project: tentative data, choice of components and architecture of operator. The second part is devoted to the development step. It deals with implementation aid systems and computation algorithms for arithmetical functions. Results and conclusions are the subject of the third part. (author)

229

Diabetes - Eye Complications  

Medline Plus

Full Text Available Diabetes - Eye Complications Introduction Patients with diabetes are more likely to have eye problems that can lead ... to the brain, which translates these signals into images we see. The central part of the retina ...

230

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... eye information on a K Card. You will need this for future eye surgery. Tell Your MDs ... be comfortable with the possibility that you may need a second surgery (called a retreatment or enhancement) ...

231

Diabetes - Eye Complications  

Medline Plus

Full Text Available ... eye problems such as blurred vision, cataract, and glaucoma. People with diabetes may have blurry vision when ... vision. Cataract can be fixed by minor surgery. Glaucoma is another disease of the eye that is ...

232

Eye Cosmetic Safety  

Science.gov (United States)

... Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products Cosmetics Print this page Share this page E-mail ... Contact Lenses Import Alerts Related to Cosmetics Eye Cosmetic Safety Most eye cosmetics are safe when used ...

233

What Is Dry Eye?  

Medline Plus

Full Text Available ... about eye health and preserving your vision. Privacy Policy Email address © 2014 American Academy of Ophthalmology medical disclaimer privacy policy sponsorship & advertising policies about us Educational Resources EyeWiki ...

234

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... Refractive Surgery Procedures Find An Eye M.D. Enter zip code here Search by Name, City, State or Subspecialty > Ask An Eye M.D. Enter your question here... Browse Top Answers > Privacy Policy > ...

235

What Is Dry Eye?  

Medline Plus

Full Text Available ... Age-related Macular Degeneration (AMD) Allergies Amblyopia (Lazy Eye) Astigmatism Bacterial Keratitis Bell's Palsy Blepharitis Cataracts Contact Lens-Related Infections Detached & Torn Retina Diabetic Retinopathy Dry Eye Floaters & ...

236

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... Page: Alternative Refractive Surgery Procedures Find An Eye M.D. Enter zip code here Search by Name, City, State or Subspecialty > Ask An Eye M.D. Enter your question here... Browse Top Answers > ...

237

LASIK eye surgery  

Science.gov (United States)

LASIK is eye surgery that permanently changes the shape of the cornea (the clear covering on the ... cornea (curvature) and the length of the eye. LASIK uses an excimer laser (an ultraviolet laser) to ...

238

Diabetic Eye Problems  

Science.gov (United States)

... this can damage your eyes. The most common problem is diabetic retinopathy. It is a leading cause ... surgery, with follow-up care. Two other eye problems can happen to people with diabetes. A cataract ...

239

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... ANSI-approved protective eyewear for risky activities. Jumping a Battery Take precautions to prevent eye injury. Never ... an eye infection, replace makeup immediately. "No Rub" a No Go To prevent infection, use the "rub ...

240

What Is Dry Eye?  

Medline Plus

Full Text Available ... of tears spreads over the eye, making the surface of the eye smooth and clear. Without this ... produced by the meibomian glands, forms the outermost surface of the tear film. Its main purpose is ...

 
 
 
 
241

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... the eye from moving. The patient may feel pressure from the eyelid holder and suction ring, similar to a finger pressed firmly on the eyelid. From the time the suction ring is put on the eye ...

242

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... approved protective eyewear for risky activities. Jumping a Battery Take precautions to prevent eye injury. Never lean over the battery and always wear safety goggles. Eye Makeup Throw ...

243

Common Eye Disorders  

Science.gov (United States)

... CDC.gov . Vision Health Initiative (VHI) Share Compartir Common Eye Disorders On this Page Anatomy Refractive Errors ... macular degeneration, cataract, diabetic retinopathy, and glaucoma. Other common eye disorders include amblyopia and strabismus. For a ...

244

Eye Disease Simulations  

Science.gov (United States)

... Research at NEI Education Programs Training and Jobs Eye Disease Simulations Listen Age-Related Macular Degeneration Cataract Diabetic ... information page Back to top Diabetic Retinopathy Diabetic Eye Disease information page Back to top Glaucoma Glaucoma information ...

245

Diabetic Eye Disease  

Science.gov (United States)

... los Ojos Cómo hablarle a su oculista Diabetic Eye Disease Listen View this module and educate yourself, family, and friends about diabetic eye disease. This module includes descriptive audio and captioning. Diabetic ...

246

Diagnostics of dry eye  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. Dry eye is a multi-factorial disease of tears and ocular surface resulting in symptoms of discomforts, vision disabilities, unstable tear film and possible damage to the ocular surface. The final diagnosis of dry eye results from collecting various data obtained in the course of several diagnostic procedures. Dry eye - diagnostic methods. Diagnosis of dry eye involves performing a series of clinical methods and laboratory tests. This paper presents some of the procedures used in the diagnosis of dry eye. Biomicroscopy of the eye with objective tests to check the tear film (Schirmer I, rose bengal, time break up precorneal tear film, verification of corneal sensitivity and impression cytology of the conjunctiva, are the optimum dry eye diagnostic routine procedures. Conclusion. The combination of clinical and histopathological methods of examination of the anterior ocular surface is the basis for a quality and precise diagnosis of dry eye.

Stankovi?-Babi? Gordana

2011-01-01

247

Diabetes - Eye Complications  

Medline Plus

Full Text Available ... eyesight and what diabetic patients can do to prevent these eye problems from happening. How The Eye ... Diabetic Retinopathy The best treatment for retinopathy is prevention. Good control of blood sugar level and blood ...

248

What Is Dry Eye?  

Medline Plus

Full Text Available ... Guidelines Home Remedies for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports ... is strictly prohibited by US and international copyright law. You may link from your website to any ...

249

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... Usage & Eye Strain Maintaining Your Sight with Diabetes Sports and Eye Protection Eyesight Risks for Smokers Veterans & ... Surgery (PDF 303K) This guide, produced by the American Academy of Ophthalmology, offers straight-forward facts about ...

250

What Is Dry Eye?  

Medline Plus

Full Text Available ... Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye Makeup Veterans What Is an Ophthalmologist? ... preserving your vision. Privacy Policy Email address © 2014 American Academy of Ophthalmology medical disclaimer privacy policy sponsorship & ...

251

Design and simulation of 64 point FFT using Radix 4 algorithm for FPGA Implementation  

Directory of Open Access Journals (Sweden)

Full Text Available The Fast Fourier Transform (FFT is one of the rudimentary operations in field of digital signal, image processing and FFT processor is a critical block in all multicarrier systems used primarily in the mobile environment. Fast Fourier transform (FFT is an efficient implementation of the discrete Fourier transform (DFT. The portability requirement of these systems is mainly responsible for the need of low power FFT architectures. . In this study, the development of 64 point FFT, based on Decimation-In- Time (DIT domain using Radix-4 algorithm. The complex multiplier is one of the most power consuming blocks in the FFT processor. A significant property of the proposed method is that the critical path of the address generator is independent from the FFT transform length N, making it extremely efficient for large FFT transforms. The results confirm the speed and area advantages for large FFTs. Although only radix-4 FFT address generation is presented in the paper, it can be used for higher radix FFT

K.Sreekanth Yadav

2013-02-01

252

School eye health appraisal  

Digital Repository Infrastructure Vision for European Research (DRIVER)

School children form an important large target group which must be screened adequately for early detection of eye diseases and prevention of blindness. A total approach in a school eye health programme must include teacher orientation and health education of children in addition to screening for eye diseases. The ocular morbidity pattern in 5135 school children of Jodhpur is discussed in this paper and it is hoped that it will be an indicator to all eye care agencies to help plan their priori...

Desai Sanjiv; Desai Rajiv; Desai N; Lohiya Shobha; Bhargava G; Kumar K

1989-01-01

253

Novel four-point-probe design and nanorobotic dual endeffector strategy for electrical characterization of as-grown SWCNT bundles  

DEFF Research Database (Denmark)

In this paper, a novel nanorobotic strategy for non-destructive and direct electrical characterization of as-grown bundles of single-walled carbon nanotubes (SWCNTs) is presented. For this purpose, test patterns of SWCNT bundles having different diameters are grown on a silicon substrate by chemical vapor deposition. A new design of microstructured four-point-probes is proposed and fabricated allowing for direct contacting of vertically aligned bundles of SWCNTs. A nanorobotic setup is upgraded into a dual endeffector system to achieve good electrical contact between four-point-probe and SWCNT bundle and to perform electrical measurements. First experimental results of non-destructive electrical characterization are presented and discussed.

Sardan Sukas, Özlem; Hansen, Torben Mikael

2010-01-01

254

Scale-specific performance of sequential and double sampling designs for point-density estimation within coniferous seedling populations  

Energy Technology Data Exchange (ETDEWEB)

The objective of this study was to assess the scale-specific (0.121 ha and 1.331 ha) performance of sequential and double sampling designs on their ability to estimate mean point-density (mean number of seedlings per 10.1 m{sup 2} quadrat) at a fixed-level of precision (0.25, ratio of the standard error of the mean to the mean) within mixed black spruce (Picea mariana (Mill.) B.S.P.) and balsam fir (Abies balsamea (L.) Mill.) seedling populations. Based on count frequency data derived from 43 naturally-regenerated seedling populations, the plans were evaluated at each scale employing sampling with replacement and sampling without replacement selection criteria. Results indicated that the double sampling design was superior to the sequential sampling design in terms of its ability to estimate the mean point-density at the specified level of precision. Furthermore, seedling populations should be greater than 0.4 ha in size if over-sampling is to be avoided and double sampling plans should be calibrated at a 0.25-10.1 m{sup 2} precision level - quadrat size if precision level bias is to be minimized 28 refs, 4 tabs

Newton, P.F. [Natural Resources Canada, Sault Ste. Marie, ON (Canada). Canadian Forest Service

1999-06-01

255

A reactor-scale point design of cone-guided implosion for Fast Ignition  

Science.gov (United States)

The formation of high-areal-density core plasma in cone-guided non-spherical implosion is required for Fast Ignition. Although many experiments have been conducted successfully at ILE and LLE using existing lasers facilities, difficulties are inherent in designing larger scale size implosion for reactors, where energy of implosion lasers will be about a MJ. One of the significant problems is high pressure at hot-spot region, if implosion is scaled up simply in similarity rule. This high pressure leads fatal break at the tip of the cone which should be located near the center of the implosion. In this work, optimization of low isentrope and high areal density implosion [1] is attempted using 2-D radiation hydrodynamic code.[4pt] [1] R. Betti et al. Phys. Plasmas, 12, 110702 (2005)[0pt] [2] H. Nagatomo, et. al, Phys. Plasmas, 14 056303 (2007).

Nagatomo, Hideo; Johzaki, Tomoyuki; Sunahara, Atsushi; Sakagami, Hitoshi

2011-11-01

256

An approach to optimal architectural and urban design from the energy efficiency point of view  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a new approach to architecture and urban design that results in an increase of the energy efficiency of buildings set close to each other, which is set as the optimization problem. The main goal is to maximize the sunlight impact on objects, in a way to minimize inter-object shading on each building. The problem is solved by the PSO (Particle Swarm Optimization algorithm and its modifications, as well as the application of PSO algorithm with niches, which makes it possible to find a large number of local optima. It turned out that the PSO algorithm with niches is especially suitable for solving the described problems. The proposed methodology is illustrated by a few examples.

Kapetina Mirna N.

2014-01-01

257

What Is Dry Eye?  

Medline Plus

Full Text Available ... moist and comfortable. The eye uses two different methods to produce tears. It can make tears at a slow, steady rate to maintain normal eye lubrication. It can also produce a lot of tears in response to eye irritation or emotion. When a foreign ...

258

What Is Dry Eye?  

Medline Plus

Full Text Available ... ask an eye M.D. Search GetEyeSmart.org Diseases & Conditions A to Z Age-related Macular Degeneration ( ... Presbyopia (Aging Eye) Stye Uveitis/Iritis See all Diseases & Conditions > Symptoms Blurriness Dark Curtain Dark Spots Discharge ...

259

What Is Dry Eye?  

Medline Plus

Full Text Available ... Conditions > Symptoms Blurriness Dark Curtain Dark Spots Discharge Double Vision Drooping Eyelid Eye Pain Eyelash Crusting Eyelid Lump Feel Something in Eye Flashes of Light Irritation Itchiness Light Sensitivity Red Eye Reduced Vision Tearing See all Symptoms > Glasses, ...

260

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... Have your LASIK surgeon record your pre- and post-op eye information on a K Card. You ... keep a record of your pre-operation and post-operation eye information. Your Eye M.D. may ...

 
 
 
 
261

Eye and orbital cavity  

International Nuclear Information System (INIS)

Radioanatomy of eyes and orbit is described. Diseases of the orbit (developmental anomalies, inflammatory diseases, lacrimal apparatus deseases, toxoplasmosis, tumors and cysts et al.), methods of foreign body localization in the eye are considered. Roentgenograms of the orbit and calculation table for foreign body localization in spherical eyes of dissimilar diameter are presented

262

Super-resolution imaging using multi- electrode CMUTs: theoretical design and simulation using point targets.  

Science.gov (United States)

This paper investigates a low computational cost, super-resolution ultrasound imaging method that leverages the asymmetric vibration mode of CMUTs. Instead of focusing on the broadband received signal on the entire CMUT membrane, we utilize the differential signal received on the left and right part of the membrane obtained by a multi-electrode CMUT structure. The differential signal reflects the asymmetric vibration mode of the CMUT cell excited by the nonuniform acoustic pressure field impinging on the membrane, and has a resonant component in immersion. To improve the resolution, we propose an imaging method as follows: a set of manifold matrices of CMUT responses for multiple focal directions are constructed off-line with a grid of hypothetical point targets. During the subsequent imaging process, the array sequentially steers to multiple angles, and the amplitudes (weights) of all hypothetical targets at each angle are estimated in a maximum a posteriori (MAP) process with the manifold matrix corresponding to that angle. Then, the weight vector undergoes a directional pruning process to remove the false estimation at other angles caused by the side lobe energy. Ultrasound imaging simulation is performed on ring and linear arrays with a simulation program adapted with a multi-electrode CMUT structure capable of obtaining both average and differential received signals. Because the differential signals from all receiving channels form a more distinctive temporal pattern than the average signals, better MAP estimation results are expected than using the average signals. The imaging simulation shows that using differential signals alone or in combination with the average signals produces better lateral resolution than the traditional phased array or using the average signals alone. This study is an exploration into the potential benefits of asymmetric CMUT responses for super-resolution imaging. PMID:24158286

You, Wei; Cretu, Edmond; Rohling, Robert

2013-11-01

263

The study of air showers by the Fly's-Eye  

International Nuclear Information System (INIS)

The Fly's-Eye is an optical-electronic system designed to detect scintillation and Cherenkov light from ultra-high-energy cosmic ray air showers. For about 9 months, 48 out of the total 67 mirrors of the system have been operated. Air showers with greater than 1017 eV are being detected and reconstructed by the University of Utah Cosmic Ray Group. The Fly's-Eye will allow the development of individual showers in the atmosphere to be studied and will be able to observe showers many kilometers away. Besides observing the spectrum and anisotropy of air showers from 1017 to 1020 eV cosmic ray nuclei, the system may also detect point sources of 1014 to 1016eV ?-rays. Preliminary data from a search for ?-rays from the vicinity of the Crab Pulsar are presented

264

Finding an Eye Care Professional  

Science.gov (United States)

Finding an Eye Care Professional Listen Finding an Eye Care Professional PDF* The National Eye Institute does not provide referrals or recommend specific eye care professionals. However, you may wish to ...

265

Childhood Eye Diseases and Conditions  

Science.gov (United States)

... the Sun Eye Health News Consumer Alerts Childhood Eye Diseases and Conditions Tweet Eye Health Lifestyle Topics Preventing ... treatment. See Also: Children's Vision Screening Common Childhood Eye Diseases & Conditions When the following diseases are suspected, the ...

266

Genetic Testing and Eye Disease  

Science.gov (United States)

... News Consumer Alerts In Focus: Genetic Testing and Eye Disease Tweet Eye Health Lifestyle Topics Preventing Eye Injuries ... Us If Your Family has a History of Eye Disease, Do You Need Genetic Testing? Thanks to news ...

267

Initial Scaling Studies and Conceptual Thermal Fluids Experiments for the Prismatic NGNP Point Design  

International Nuclear Information System (INIS)

The objective of this report is to document the initial high temperature gas reactor scaling studies and conceptual experiment design for gas flow and heat transfer. The general approach of the project is to develop new benchmark experiments for assessment in parallel with CFD and coupled CFD/ATHENA/RELAP5-3D calculations for the same geometry. Two aspects of the complex flow in an NGNP are being addressed: (1) flow and thermal mixing in the lower plenum (''hot streaking'' issue) and (2) turbulence and resulting temperature distributions in reactor cooling channels (''hot channel'' issue). Current prismatic NGNP concepts are being examined to identify their proposed flow conditions and geometries over the range from normal operation to decay heat removal in a pressurized cooldown. Approximate analyses are being applied to determine key non-dimensional parameters and their magnitudes over this operating range. For normal operation, the flow in the coolant channels can be considered to be dominant forced convection with slight transverse property variation. The flow in the lower plenum can locally be considered to be a situation of multiple buoyant jets into a confined density-stratified crossflow--with obstructions. Experiments are needed for the combined features of the lower plenum flows. Missing from the typical jet experiments are interactions with nearby circular posts and with vertical posts in the vicinity of vertical walls--with near stagnant surroundings at one extreme and significant crossflow at the other. Two heat transfer experiments are being considered. One addresses the ''hot channel'' problem, if necessary. The second experiment will treat heated jets entering a model plenum. Unheated MIR (Matched-Index-of-Refraction) experiments are first steps when the geometry is complicated. One does not want to use a computational technique which will not even handle constant properties properly. The MIR experiment will simulate flow features of the paths of jets as they mix in flowing through the array of posts in a lower plenum en route to the single exit duct. Initial conceptual designs for such experiments are described

268

Initial Scaling Studies and Conceptual Thermal Fluids Experiments for the Prismatic NGNP Point Design  

Energy Technology Data Exchange (ETDEWEB)

The objective of this report is to document the initial high temperature gas reactor scaling studies and conceptual experiment design for gas flow and heat transfer. The general approach of the project is to develop new benchmark experiments for assessment in parallel with CFD and coupled CFD/ATHENA/RELAP5-3D calculations for the same geometry. Two aspects of the complex flow in an NGNP are being addressed: (1) flow and thermal mixing in the lower plenum ("hot streaking" issue) and (2) turbulence and resulting temperature distributions in reactor cooling channels ("hot channel" issue). Current prismatic NGNP concepts are being examined to identify their proposed flow conditions and geometries over the range from normal operation to decay heat removal in a pressurized cooldown. Approximate analyses are being applied to determine key non-dimensional parameters and their magnitudes over this operating range. For normal operation, the flow in the coolant channels can be considered to be dominant forced convection with slight transverse property variation. The flow in the lower plenum can locally be considered to be a situation of multiple buoyant jets into a confined density-stratified crossflow -- with obstructions. Experiments are needed for the combined features of the lower plenum flows. Missing from the typical jet experiments are interactions with nearby circular posts and with vertical posts in the vicinity of vertical walls - with near stagnant surroundings at one extreme and significant crossflow at the other. Two heat transfer experiments are being considered. One addresses the "hot channel" problem, if necessary. The second experiment will treat heated jets entering a model plenum. Unheated MIR (Matched-Index-of-Refraction) experiments are first steps when the geometry is complicated. One does not want to use a computational technique which will not even handle constant properties properly. The MIR experiment will simulate flow features of the paths of jets as they mix in flowing through the array of posts in a lower plenum en route to the single exit duct. Initial conceptual designs for such experiments are described.

D. M. McEligot; G. E. McCreery

2004-09-01

269

Analysis of EEG Related Saccadic Eye Movement  

Science.gov (United States)

Our final goal is to establish the model for saccadic eye movement that connects the saccade and the electroencephalogram(EEG). As the first step toward this goal, we recorded and analyzed the saccade-related EEG. In the study recorded in this paper, we tried detecting a certain EEG that is peculiar to the eye movement. In these experiments, each subject was instructed to point their eyes toward visual targets (LEDs) or the direction of the sound sources (buzzers). In the control cases, the EEG was recorded in the case of no eye movemens. As results, in the visual experiments, we found that the potential of EEG changed sharply on the occipital lobe just before eye movement. Furthermore, in the case of the auditory experiments, similar results were observed. In the case of the visual experiments and auditory experiments without eye movement, we could not observed the EEG changed sharply. Moreover, when the subject moved his/her eyes toward a right-side target, a change in EEG potential was found on the right occipital lobe. On the contrary, when the subject moved his/her eyes toward a left-side target, a sharp change in EEG potential was found on the left occipital lobe.

Funase, Arao; Kuno, Yoshiaki; Okuma, Shigeru; Yagi, Tohru

270

Recent Advances in Optimal Design of Structures from a Reliability Point of View  

DEFF Research Database (Denmark)

Structural optimisation and structural reliability theory are considered. Both of these areas have developed during the last two decades from being of purely theoretical interest to areas useful in practical design. The main elements of structural reliability theory are described in the second section. First, a short review of the reliability theory for structural elements (e.g., beams and tubular joints) based on the so-called ß-index philosophy (Cornell[1], Ditlevsen[2], and Hasofer and Lind[3]) is given. Detailed descriptions are given in textbooks such as those by Thoft-Christensen and Baker[4] and Madsen et al.[5]. Next a heuristic method, the so-called ß-unzipping method[6] is mentioned. This method can be used to estimate the reliability of a structural system if some modelling assumptions are fulfilled. In the third section some elements of structural optimisation theory are described. A reliability-based structural optimisation problem is formulated. The formulation is a natural extension of the commonly used formulations in deterministic, classical structural optimisation. Some methods for solving the reliability-based optimisation problem are mentioned[7, 8, 9, 10]. In the fourth and fifth sections two examples of optimisation with reliability constraints of steel-jacket offshore platforms are given. In the first example special consideration is given to the reliability of the tubular joints and in the second example a three-dimensional model is considered.

Thoft-Christensen, Palle; SØrensen, John Dalsgaard

1987-01-01

271

Electrical and Thermal View Points for Designing Conduction-Cooled Specimen Holder for Short Sample Testing  

Science.gov (United States)

Theelectrical and stabilitypropertiesof superconductivestrandsareoftencharacterizedby short sample testing.These tests are often done in a measurement system where the sample is cooled by liquid cryogen or cold gas flow. In both approaches, the sample temperature during a measurement is stabilized by the abundance of available cooling power. This also helps to protect the sample during a thermal runaway i.e. quench. However, in some characterizations, e.g. minimum quench energy testing, the cooling conditions can have a significant effect on the results. Therefore a more adiabatic solution is prefer able as iten able seasier comparison of the results from different measurement stations. One solution to achieving the desired adiabacy is to use conduction-cooling and vacuum insulation. As there is no cooling fluidtorelyon, as cheme for sample protection has to be implemented. Inaconduction-cooled setup, one way to protect the sampleis to use an active protection system in conjunction with aproperly designed sample holder. In this publication, we present an electrical and thermal analysis of a conduction-cooled sample holder suitable for both critical current and minimum quench energy measurements. A coupled electro-thermal finite element method model was constructed to study the sample holder performance during measurement. For our application, the performance is defined by the ohmic losses in the holder component sand by the recovery time from as amplequench.

Järvelä, J.; Stenvall, A.; Mikkonen, R.

272

Development of calculation method for the system design parameters at the design point of the passive DHR system in KALIMER-600  

Energy Technology Data Exchange (ETDEWEB)

The conceptual design of a sodium cooled liquid metal reactor, KALIMER (Korea Advanced LIquid MEtal Reactor) of which electric power is 150 MWe, has performed. A revised design concept up-rating electric capacity to 600 MWe, named as KALIMER-600, has been currently developed. The Residual Heat Removal (RHR) system under a loss of normal heat sink accident of KALIMER-600 is characterized by the concept of PDRC (Passive Decay heat Removal Circuit) and it has superiority in the aspect that an enough decay heat removal capacity can be provided and any additional consideration associated with the core thermal power increase can also be neglected since it uses a very simple concept of direct reactor pool cooling. In this regard, a proper method for setting up the steady state design parameters at the design point of PDRC system should be required to secure a sufficient decay heat removal capacity of the RHR system in KALIMER-600. This study describes developing procedure of two different methods for determining the design parameters of PDRC system. They are the rough and the detail analysis method, and the methods have a mutual complementary nature. On the basis of the relationship between the various design parameters produced by using the developed methods, overall characteristics of PDRC system corresponding to the variations of system design parameters have been investigated, and more detail calculations are carried out using the results of the investigations such as the variations of the temperature, pressure loss, mass flowrate and UA values in each heat transfer circuit or heat exchanger in PDRC system. This report also provides the brief procedure of a computational programming for the detail analysis method and, using the computational routine, it is expected that an expansion of applicability to flexibly cope with a design change of PDRC system in KALIMER-600 is possible.

Eoh, Jae Hyuk; Sim, Yoon Sub; Kim, Seong O

2004-01-01

273

School eye health appraisal  

Directory of Open Access Journals (Sweden)

Full Text Available School children form an important large target group which must be screened adequately for early detection of eye diseases and prevention of blindness. A total approach in a school eye health programme must include teacher orientation and health education of children in addition to screening for eye diseases. The ocular morbidity pattern in 5135 school children of Jodhpur is discussed in this paper and it is hoped that it will be an indicator to all eye care agencies to help plan their priorities in the delivery of school based eye care.

Desai Sanjiv

1989-01-01

274

Design and realization of a handheld vibrometer system for noncontact in-vivo detection of microvibrations of the human eye to determine the intraocular pressure (IOP)  

Science.gov (United States)

To allow measurements of the intraocular pressure (IOP) by glaucoma patients themselves (self-tonometry) a handheld-interferometer system for non-contact in vivo measurements of microvibrations of the human eye was realized. The measurement principle is based on the dependence of the resonance frequencies of the human eye on the IOP. To analyze this, the human eye is stimulated by ultrasonic waves and the induced microvibrations are measured with a vibrometer and processed by a DSP unit. Beside a stabilized diode laser and a low noise photodetector an exact three-dimensional positioning system had to be developed to guarantee reliable measurements. To investigate the corresponding requirements a camera-based system for the detection of human eye movements was developed and test series with several persons were made. Based on these results an adjustment unit was integrated in a miniaturized interferometer system: After a short self-adjusting procedure lateral to the setup by overlaying two targets of a highly sensitive optical system the correct measuring distance between the cornea and the vibrometer parallel to the optical axis is determined automatically by an astigmatic auto-focus system. With this handheld-vibrometer in vivo measurements with several test persons were made with very good results concerning the reliability and handling capability.

Gundlach, Arnd; Rawer, Rainer; Hey, Stefan; Stork, Wilhelm; Mueller-Glaser, Klaus-Dieter

2002-06-01

275

Through Our Parents' Eyes  

Science.gov (United States)

How does an institution help tell the story of the community it is located in? This type of endeavor can take many approaches, and the University of Arizona seems to have found a fantastic way to do so. Working with a variety of organizations and individuals throughout the greater Tucson and Southern Arizona community. Through Our Parents' Eyes: History & Culture of Southern Arizona was started in the mid-1990s. The project was designed to bring together the diverse human experiences of the region by drawing on a wide range of documents, oral histories, historic images, and video clips. The project and this website feature a number of teaching resources, regional histories, and primary documents for use by anyone interested in the region. Some of these resources have been collected into thematic presentations, including "Words & Place: Native Literature of the American Southwest" and "War Relocation Authority Camps in Arizona, 1942-1946".

276

Initial performance improvements due to design modifications for the Pointing Control System on the Hubble Space Telescope  

Science.gov (United States)

Shortly after Hubble Space Telescope was deployed on orbit it became apparent that the Pointing Control System was experiencing unexpectedly large disturbances during certain portions of the orbit. While these disturbances were most pronounced during transitions of the Earth's shadow, significant disruptions to the pointing occurred at other times in the orbit. Careful analysis of the flight data has lead to the conclusion that the disturbances are caused by a combination of rapid thermal deformations of the Solar Arrays together with striction-friction mechanisms within the array that randomly release stored thermal/mechanical energy. This paper describes the baseline pointing control system design and the flight data that characterized the effects of the extraneous disturbances. The paper goes on to describe the procedure for modifying the onboard controller to attenuate the disturbances to levels consistent with the science operations. Flight data demonstrating the improved performance are shown and are tabulated to compare performance prior to and after phase I of the redesign.

Nurre, G. S.; Sharkey, J. P.; Waites, H. B.

1991-01-01

277

Poverty and Eye Health  

Directory of Open Access Journals (Sweden)

Full Text Available Poverty and eye health, including vision disability from vision impairment and blindness, are believed to be interrelated. The relationship between poverty and eye health can be interpreted as being two-fold, in the sense that poverty may be a cause of poor eye health and poor eye health may lead to or deepen poverty. Evidence shows that the burden of vision impairment is high in poor people and vision impairment and poverty are linked to each other. However the empirical evidence to answer the questions—Does poverty perpetuate poor eye health? How and why? Does poor eye health deepen poverty?—is sparse globally; especially from low and middle income countries (LMICs. This article therefore aims to examine published information and other secondary data sources that provide insight on the relationship between poverty and eye health, including eye disability caused from vision impairment and blindness. The article provides a conceptual understanding of poverty related attributes that contribute to eye disability from vision impairment and blindness, using evidence sourced from poverty and eye health research studies. The article interrogates general theories and beliefs that have been conceptualised in relation to the impact that the vicious cycle of poverty has on eye health and the contribution of poor eye health on an individual’s poverty status. The major outcomes of this article include: 1 identifying gaps in linking poverty and eye health, 2 establishing key issues that will assist in the development of a theoretical framework, and 3 preparing more appropriately for further investigation on the association between poverty and eye health.

Jyoti Jaggernath

2014-07-01

278

Improvements in packages comprising eye baths and eye lotions  

International Nuclear Information System (INIS)

A new packaged assembly comprising an eye bath and eye lotion is described. The eye bath is shaped for application to the eye; it has a rim portion formed so as to provide a smooth skin-contacting surface and is sealed to a lid at a position removed from the skin-contacting area. The eye bath is formed in a sterile condition and aseptically filled to an appropriate level with eye lotion by a blow moulding process. The eye bath and its contents are sterilised after sealing by radioactive sterilsation. This packaged assembly is an improvement over previous eye bath assemblies in that it allows the eye bath to be used in a sterile form. It is also more comfortable and convenient to use than other sterile forms of eye treatment such as eye drops or jets of eye wash. Furthermore, bathing the eye provides a more prolonged treatment. (U.K.)

279

The Colossal Cosmic Eye  

Science.gov (United States)

Eighty-five million years ago on small planet Earth, dinosaurs ruled, ignorant of their soon-to-come demise in the great Jurassic extinction, while mammals were still small and shy creatures. The southern Andes of Bolivia, Chile, and Argentina were not yet formed and South America was still an island continent. Eighty-five million years ago, our Sun and its solar system was 60,000 light years away from where it now stands [1]. Eighty-five million years ago, in another corner of the Universe, light left the beautiful spiral galaxy NGC 1350, for a journey across the universe. Part of this light was recorded at the beginning of the year 2000 AD by ESO's Very Large Telescope, located on the 2,600m high Cerro Paranal in the Chilean Andes on planet Earth. Astronomers classify NGC 1350 as an Sa(r) type galaxy, meaning it is a spiral with large central regions. In fact, NGC 1350 lies at the border between the broken-ring spiral type and a grand design spiral with two major outer arms. It is about 130,000 light-years across and, hence, is slightly larger than our Milky Way. The rather faint and graceful outer arms originate at the inner main ring and can be traced for almost half a circle when they each meet the opposite arm, giving the impression of completing a second outer ring, the "eye". The arms are given a blue tint as a result of the presence of very young and massive stars. The amount of dust, seen as small fragmented dust spirals in the central part of the galaxy and producing a fine tapestry that bear resemblance with blood vessels in the eye, is also a signature of the formation of stars.

2005-09-01

280

Teamwork for eye care  

Directory of Open Access Journals (Sweden)

Full Text Available Human resource development (HRD – the development of the people who deliver health care – has been identified as one of the key pillars of eye health delivery. HRD is one of the essential building blocks of the World Health Organization (WHO Global Action Plan: ‘Towards universal eye health’. The importance of HRD is also recognised beyond eye care, as can be seen in the WHO Health Systems approach.

M Babar Qureshi

2014-04-01

 
 
 
 
281

The questionably dry eye.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper is concerned with the recognition of the dry eye when the clinical diagnosis is in doubt and other external eye diseases may be present. Papillary conjunctivitis is common to the dry eye as well as other pathological conditions and confuses the diagnosis. We have correlated the factors involved in the assessment for dryness. We have shown that particulate matter in the unstained tear film is associated with low tear lysozyme concentration. Tear flow and tear lysozyme are not necess...

Mackie, I. A.; Seal, D. V.

1981-01-01

282

Design and Integration of an All-Magnetic Attitude Control System for FASTSAT-HSV01's Multiple Pointing Objectives  

Science.gov (United States)

The FASTSAT-HSV01 spacecraft is a microsatellite with magnetic torque rods as it sole attitude control actuator. FASTSAT s multiple payloads and mission functions require the Attitude Control System (ACS) to maintain Local Vertical Local Horizontal (LVLH)-referenced attitudes without spin-stabilization, while the pointing errors for some attitudes be significantly smaller than the previous best-demonstrated for this type of control system. The mission requires the ACS to hold multiple stable, unstable, and non-equilibrium attitudes, as well as eject a 3U CubeSat from an onboard P-POD and recover from the ensuing tumble. This paper describes the Attitude Control System, the reasons for design choices, how the ACS integrates with the rest of the spacecraft, and gives recommendations for potential future applications of the work.

DeKock, Brandon; Sanders, Devon; Vanzwieten, Tannen; Capo-Lugo, Pedro

2011-01-01

283

Eye injuries in children.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report a retrospective study of children's eye injuries treated during 1977 at Helsinki University Eye Hospital. There were 110 cases representing 34.5% of all eye injuries and 3% of all patients treated in 1977; 81.8% were boys and 18.2% girls. Half of the injuries were caused by another child, one-third were self-inflicted, and the rest were other accidents. The risk of eye injury in girls was low and stable at all ages, but in boys the risk grew markedly at the age of 8 years. The commo...

Niiranen, M.; Raivio, I.

1981-01-01

284

Prevention of Eye Injuries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In Canada 30,000 people are registered as blind; in one third of these, blindness might have been avoided. Prevention is the key to reducing the number of eye injuries and blind eyes. The role of the family physician in early identification of treatable conditions and in the education of patients is discussed, but responsibility for prevention belongs to all physicians. The success of prevention is seen in the great reduction in eye injuries in industry and sports since eye protectors have be...

Pashby, Tom

1981-01-01

285

Improving eye care in the primary health care setting  

Directory of Open Access Journals (Sweden)

Full Text Available One of the challenges facing primary health care in South Africa is the delivery of quality eye care to all South Africans. In this regard the role of the primary health care worker, as the first point of contact, is crucial. This paper reports on the problems primary health care workers experience in providing quality eye care in Region B of the Free State. Problems identified by those involved in the study include the cumbersome referral system, the unavailability of appropriate medicine at clinics, the insufficient knowledge of primary health care workers regarding eye conditions and the lack of communication between the various eye care service providers. Suggestions to address the problems identified included more in-service training of primary health care workers regarding eye conditions, liaison with NGO’s providing eye care, decentralisation of services and the establishment of an eye care committee in the region.

M de Wet

2000-09-01

286

Different schematic eyes and their accuracy to the in vivo eye: a quantitative comparison study  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Current ophthalmic technology allows the manipulation of eye components, such as anterior cornea and lens, of the human eye with a considerable precision and customization. This technology opens up the possibility of exploiting some characteristics of the eye in order to improve the methods of corre [...] cting optical aberrations. Moreover, product development and research for the eye-care professional has reached very high standards, since there is nowadays software available to design and simulate practically any mechanical or optical characteristic of the product, even before it is thrown into production line. Although quite similar in the general form, different human eye models simulate the image formation by considering different property combinations in the constitutive elements of the eye structure (such as refraction index and surface curvatures), producing retinal images that resemble very closely those of the biological eye. Using optical design software, we have implemented a simulation of 5 well-known schematic eyes available in the literature. These models were the Helmholtz-Laurance, Gullstrand, Emsley, Greivenkamp and Liou & Brennan. The optical performance of these different models was compared using different quantitative optical quality parameters. The model of Liou and Brennan, contains features of the biological eye that were not considered in previous models, as the distribution of a gradient refraction index and a decentered pupil. Furthermore, it has great reliability since it takes into account the mean value of empirical measurements of the in vivo eye in order to define size and parameters such as anterior and posterior curvature of cornea, lens, axial length, etc. Comparisons between the MTF (Modulation Transfer Function), spot diagrams and ray fan showed the difference in image quality between eye models, and the Strehl Ratio was also used as a parameter of comparison. A careful comparison between the different models showed that the first four schematic eyes have better optical quality than what is expected for the general and healthy emmetropic in vivo eye. Liou and Brennan schematic eye is the one that most closely resembles the in vivo biological eye. Therefore, in applications, such as research or product development for customized vision correction, which must consider optical properties intrinsic to the biological eye, we recommend this latter model; for applications that do not require refraction-limited performance, most of the other models should be a good approximation.

Marina Storani de, Almeida; Luis Alberto, Carvalho.

287

Different schematic eyes and their accuracy to the in vivo eye: a quantitative comparison study  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Current ophthalmic technology allows the manipulation of eye components, such as anterior cornea and lens, of the human eye with a considerable precision and customization. This technology opens up the possibility of exploiting some characteristics of the eye in order to improve the methods of corre [...] cting optical aberrations. Moreover, product development and research for the eye-care professional has reached very high standards, since there is nowadays software available to design and simulate practically any mechanical or optical characteristic of the product, even before it is thrown into production line. Although quite similar in the general form, different human eye models simulate the image formation by considering different property combinations in the constitutive elements of the eye structure (such as refraction index and surface curvatures), producing retinal images that resemble very closely those of the biological eye. Using optical design software, we have implemented a simulation of 5 well-known schematic eyes available in the literature. These models were the Helmholtz-Laurance, Gullstrand, Emsley, Greivenkamp and Liou & Brennan. The optical performance of these different models was compared using different quantitative optical quality parameters. The model of Liou and Brennan, contains features of the biological eye that were not considered in previous models, as the distribution of a gradient refraction index and a decentered pupil. Furthermore, it has great reliability since it takes into account the mean value of empirical measurements of the in vivo eye in order to define size and parameters such as anterior and posterior curvature of cornea, lens, axial length, etc. Comparisons between the MTF (Modulation Transfer Function), spot diagrams and ray fan showed the difference in image quality between eye models, and the Strehl Ratio was also used as a parameter of comparison. A careful comparison between the different models showed that the first four schematic eyes have better optical quality than what is expected for the general and healthy emmetropic in vivo eye. Liou and Brennan schematic eye is the one that most closely resembles the in vivo biological eye. Therefore, in applications, such as research or product development for customized vision correction, which must consider optical properties intrinsic to the biological eye, we recommend this latter model; for applications that do not require refraction-limited performance, most of the other models should be a good approximation.

Marina Storani de, Almeida; Luis Alberto, Carvalho.

2007-06-01

288

Design, simulation and fabrication of a novel contact-enhanced MEMS inertial switch with a movable contact point  

International Nuclear Information System (INIS)

A novel inertial switch based on a micro-electro-mechanical system (MEMS) was designed, which consists of three main parts: a proof mass as the movable electrode, a cross beam as the stationary electrode and a movable contact point to prolong the contact time. A MATLAB/Simulink model, which had been verified by comparison with ANSYS transient simulation, was built to simulate the dynamic response, based on which the contact-enhancing mechanism was confirmed and the dependence of threshold acceleration on the proof mass thickness was studied. The simulated dynamic responses under various accelerations exhibit satisfactory device behaviors: the switch-on time is prolonged under transient acceleration; the switch-on state is more continuous than the conventional design under long lasting acceleration. The inertial micro-switch was fabricated by multilayer electroplating technology and then tested by a drop hammer experiment. The test results indicate that the contact effect was improved significantly and a steady switch-on time of over 50 µs was observed under half-sine wave acceleration with 1 ms duration, in agreement with the dynamic simulation

289

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... corneal tissue is created using an automated microsurgical device, either a laser or blade. This corneal flap is lifted and folded back. Then the excimer laser preprogrammed with the patient's unique eye measurements is centered above the eye. The surgeon checks ...

290

Diabetes - Eye Complications  

Medline Plus

Full Text Available ... vessels. The blood vessels of the eyes are small. When they become weak, they leak, burst, or become blocked. Diabetic Retinopathy The weakening of the blood vessels of the eyes is known as diabetic retinopathy. “Retinopathy” means disease of the retina. It is the most serious ...

291

What Is Dry Eye?  

Medline Plus

Full Text Available ... eye health and preserving your vision. Privacy Policy Email address © 2014 American Academy of Ophthalmology medical disclaimer privacy policy sponsorship & advertising policies about us For Medical Providers EyeWiki contact us sitemap Reproducing text or images from this ...

292

Eye tissues study  

Science.gov (United States)

Theoretical and in vitro and in vivo experimental study of spectral and polarization characteristics of the human and rabbit eye tissues are presented. The possibility of control of optical properties of eye cornea, lens and sclera is discussed and realized experimentally for glucose solution as the refractive index matching factor.

Tuchin, Valery V.; Bashkatov, Alexey N.; Maksimova, Irina L.; Sinichkin, Yurii P.; Simonenko, Georgy V.; Genina, Elina A.; Lakodina, Nina A.

2001-08-01

293

Eye-Tracking  

Directory of Open Access Journals (Sweden)

Full Text Available Eye-tracking: one of the newest and most efficient methods of improving on-line marketing communication is called eye-tracking. Marketers have borrowed this technique, usually used in psychological and medical research, in order to study web users with the help of a video camera incorporated in the monitor.

Gabriela GROSSECK

2006-01-01

294

Analyzing Head and Eye Movement System with CORBA  

Directory of Open Access Journals (Sweden)

Full Text Available In order to study the vestibular system in different organs of movement as well as their collaboration between working mechanism, this paper designs a model of the common object request broker architecture (CORBA for the head and eye movement system based on the vestibular function. By analyzing physiological characteristics of the head and eye movement model, and further introducing the structure features of CORBA. It focus on the component composition and the model design of CORBA components library. According to the physiology work model of head and eye movement, the CORBA model of head and eye movement is established. As well as the structure of the model is designed in real application of head and eye movement measurement system. This paper provides a new way to research the head and eye movement system through using mathematical modeling and application structure which is based on vestibular function.    

Wang Changyuan

2013-11-01

295

[Pharmaceutical investigation of vancomycin hydrochloride eye drops and their topical application to MRSA eye infection].  

Science.gov (United States)

Two formulations of 0.5% vancomycin hydrochloride (VM) eye drops (VM-B and VM-C eye drops) were prepared by dissolving commercial VM powder for injection with preserved water B (PWB) containing phosphate buffer and preserved water C (PWC) containing only antimicrobial preservative, respectively. The VM-B eye drops have neutral pH (about 6.3), and the VM-C eye drops acidic pH of about 3.5. The pharmaceutical examination of these eye drops was performed regarding its clinical application to MRSA eye infection. In an irritability test using a rabbit's eye, the average number of winks after instillation of one drop of VM-B eye drops was 0.8 times/min and significantly smaller than that of VM-C eye drops (2.0 times/min). In dark storage at 4 degrees C, no change of VM concentration in both eye drops was observed for 25 weeks after preparation and the mean residual concentrations as determined by the HPLC-UV (240 nm) method were constant over 90% for 8 weeks, of the initial concentration. However, the residual VM concentration of VM-B eye drops under a room condition declined to 58% after 4 weeks and 20% after 8 weeks, and VM in light storage at 40 degrees C was not detectable after 8 weeks. The drug concentration of VM-C eye drops declined to 83% after 4 weeks and 74% after 8 weeks under a room condition, and to 46% after 4 weeks and 20% after 8 weeks under light storage at 40 degrees C. Under these storage conditions, the precipitation of VM related crystals was observed in both the eye drops when the residual percentage of VM was lower than 80%. Judging from HPLC chromatograms of a solution of the precipitated crystals, it was suggested that this crystal was degradation products of VM. The VM-B eye drops was applied to a patient with MRSA eye infection, because other medication was not effective. After continuous instillation of a drop per times every hour to both eyes, MRSA in corneal culture turned out negative after one week, and the clinical condition was remarkably improved. On the basis of the result of eye-irritability, VM-B eye drops with neutral pH was suggested to be superior to acidic VM-C eye drops from a safety point of view. It was also indicated that VM-B eye drops can be effectively used for 8 weeks under dark storage at 4 degrees C for MRSA eye infection, which is a useful piece information for the proper usage of the VM eye drops. PMID:11433777

Itoh, M; Aoyama, T; Iemoto, A; Nakajima, K; Amano, S; Nakamura, H; Sato, H; Iga, T

2001-06-01

296

Eye Tracking Studies of Normative and Atypical Development  

Science.gov (United States)

This paper reviews the use of eye tracking measures (saccades, smooth-pursuit eye movements, fixations during scene and face perception, and pupillary dilation) to study typical and clinical populations of children and adolescents and evaluates the use of these measures. The studies are evaluated with a focus on points that may be of general…

Karatekin, Canan

2007-01-01

297

Random assignment of intervention points in two-phase single-case designs: data-division-specific distributions.  

Science.gov (United States)

The present study explored the statistical properties of a randomization test based on the random assignment of the intervention point in a two-phase (AB) single-case design. The focus is on randomization distributions constructed with the values of the test statistic for all possible random assignments and used to obtain p values. The shape of those distributions is investigated for each specific data division defined by the moment in which the intervention is introduced. Another aim of the study consisted in testing the detection of inexistent effects (i.e., production of false alarms) in autocorrelated data series, in which the assumption of exchangeability between observations may be untenable. In this way, it was possible to compare nominal and empirical Type I error rates to obtain evidence on the statistical validity of the randomization test for each individual data division. The results suggest that, when either of the two phases has considerably fewer measurement times, Type I errors may be too probable and, hence, the decision-making process to be carried out by applied researchers may be jeopardized. PMID:19102475

Solanas, Antonio; Sierra, Vicenta; Quera, Vicenç; Manolov, Rumen

2008-10-01

298

Application of 3-Dimensional Printing Technology to Construct an Eye Model for Fundus Viewing Study  

Science.gov (United States)

Objective To construct a life-sized eye model using the three-dimensional (3D) printing technology for fundus viewing study of the viewing system. Methods We devised our schematic model eye based on Navarro's eye and redesigned some parameters because of the change of the corneal material and the implantation of intraocular lenses (IOLs). Optical performance of our schematic model eye was compared with Navarro's schematic eye and other two reported physical model eyes using the ZEMAX optical design software. With computer aided design (CAD) software, we designed the 3D digital model of the main structure of the physical model eye, which was used for three-dimensional (3D) printing. Together with the main printed structure, polymethyl methacrylate(PMMA) aspherical cornea, variable iris, and IOLs were assembled to a physical eye model. Angle scale bars were glued from posterior to periphery of the retina. Then we fabricated other three physical models with different states of ammetropia. Optical parameters of these physical eye models were measured to verify the 3D printing accuracy. Results In on-axis calculations, our schematic model eye possessed similar size of spot diagram compared with Navarro's and Bakaraju's model eye, much smaller than Arianpour's model eye. Moreover, the spherical aberration of our schematic eye was much less than other three model eyes. While in off- axis simulation, it possessed a bit higher coma and similar astigmatism, field curvature and distortion. The MTF curves showed that all the model eyes diminished in resolution with increasing field of view, and the diminished tendency of resolution of our physical eye model was similar to the Navarro's eye. The measured parameters of our eye models with different status of ametropia were in line with the theoretical value. Conclusions The schematic eye model we designed can well simulate the optical performance of the human eye, and the fabricated physical one can be used as a tool in fundus range viewing research. PMID:25393277

Li, Xinhua; Gao, Zhishan; Yuan, Dongqing; Liu, Qinghuai

2014-01-01

299

Data eye monitor method and apparatus  

Science.gov (United States)

An apparatus and method for providing a data eye monitor. The data eye monitor apparatus utilizes an inverter/latch string circuit and a set of latches to save the data eye for providing an infinite persistent data eye. In operation, incoming read data signals are adjusted in the first stage individually and latched to provide the read data to the requesting unit. The data is also simultaneously fed into a balanced XOR tree to combine the transitions of all incoming read data signals into a single signal. This signal is passed along a delay chain and tapped at constant intervals. The tap points are fed into latches, capturing the transitions at a delay element interval resolution. Using XORs, differences between adjacent taps and therefore transitions are detected. The eye is defined by segments that show no transitions over a series of samples. The eye size and position can be used to readjust the delay of incoming signals and/or to control environment parameters like voltage, clock speed and temperature.

Gara, Alan G. (Mount Kisco, NY); Marcella, James A. (Rochester, MN); Ohmacht, Martin (Yorktown Heights, NY)

2012-01-31

300

Eye and orbital cancer  

International Nuclear Information System (INIS)

Diseases of the eye and orbital contents which can be treated by radiation therapy are relatively uncommon. They include benign diseases such as pterygium, orbital pseudo-tumor, and Graves' exophthalmos. Malignant diseases in adults include orbital and choroidal metastases, lacrimal gland tumors, carcinoma of the bulbar conjunctiva, orbital lymphomas and melanomas. Pediatric malignancies include retinoblastomas, optic nerve gliomas, and orbital rhabdomyosarcomas. Orbital irradiation may result in a variety of normal eye and orbital tissues responses. Those responses may occur when irradiating the eye or orbital diseases listed above or non-orbital primary tumors, such as nasal cavity and paranasal sinus tumors

 
 
 
 
301

Perceptions of eye health in schools in Pakistan  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Research exploring children's and their teachers' perceptions of eye health is lacking. This paper reports for the first time on perceptions of primary schoolchildren and their teachers of healthy and diseased eyes, things that keep eyes healthy and damage them, and what actions to be taken in case of an eye injury. Methods Using draw and write technique, 160 boys and girls (9–12 years old attending four primary schools in Abbottabad district, northern Pakistan, were invited to draw pictures in response to a set of semi-structured questions and then label them. Sixteen teachers who were currently teaching the selected students were interviewed one-on-one. Results Analysis of text accompanying 800 drawings and of the interview scripts revealed that most children and teachers perceived healthy eyes to be those which could see well, and diseased eyes to be those which have redness, watering, dirty discharge, pain, and itching; or those which have "weak eyesight" and blindness. Among things that students and teachers thought damage the eyes included sun, television, and sharp pointed objects, particularly pencils. Teachers noted that children with eye problems "have difficulty seeing the blackboard well", "screw up their eyes", and "hold their books too close". Conclusion We conclude that schoolchildren and their teachers had a good knowledge of eye health, but many of them had serious misconceptions e.g., use of kohl, medicines and eye drops keeps eyes healthy. Kohl is an important source of lead and can reduce children's intelligence even at low blood levels. Health education in schools must take into account children's existing knowledge of and misconceptions about various aspects of eye health. Such steps if taken could improve the relevance of eye health education to schoolchildren.

Qureshi Mohammad

2006-03-01

302

Eye movements of laterally eyed birds are not independent.  

Science.gov (United States)

Most birds have laterally placed eyes with two largely separated visual fields. According to studies in pigeons laterally eyed birds move their eyes independently in most situations, eye coordination just occurred during converging saccades towards frontal stimuli. Here we demonstrate for the first time that laterally eyed zebra finches show coordinated eye movements, regarding direction and amplitude. Spontaneous and visually elicited movements of the two eyes were recorded simultaneously, using a newly developed eye tracking system. We found that, if one eye moves in a certain direction, the other eye simultaneously performs a counter-movement in the opposite direction. Based on these data we developed a hypothesis of how laterally eyed birds cope with the situation in which the left and right eye simultaneously obtain images with different content. We suggest that the counter-movements maintain the spatial relationship of the two visual fields. ;Oculospatial constancy', as we call it, facilitates the combination of the left and right visual percept on the level of peripheral or unattended viewing, and the localization of appearing stimuli within the whole visual field. As soon as two visual stimuli simultaneously appear in the left and right visual field, the birds decide on one stimulus and direct the fovea of the appropriate eye towards it for high resolution analysis, the other eye simultaneously performing a counter-saccade. This leads to the assumption that, in contrast to simultaneous peripheral perception with two eyes, the processing of foveal information is possible only for one eye at one time. PMID:19411551

Voss, Joe; Bischof, Hans-Joachim

2009-05-01

303

The Cat's Eye Nebula  

Science.gov (United States)

This NASA Hubble Space Telescope image shows one of the most complex planetary nebulae ever seen, NGC 6543, nicknamed the 'Cat's Eye Nebula.' Hubble reveals surprisingly intricate structures including concentric gas shells, jets of high-speed gas and unusual shock-induced knots of gas. Estimated to be 1,000 years old, the nebula is a visual 'fossil record' of the dynamics and late evolution of a dying star. A preliminary interpretation suggests that the star might be a double-star system. The suspected companion star also might be responsible for a pair of high-speed jets of gas that lie at right angles to this equatorial ring. If the companion were pulling in material from a neighboring star, jets escaping along the companion's rotation axis could be produced. These jets would explain several puzzling features along the periphery of the gas lobes. Like a stream of water hitting a sand pile, the jets compress gas ahead of them, creating the 'curlicue' features and bright arcs near the outer edge of the lobes. The twin jets are now pointing in different directions than these features. This suggests the jets are wobbling, or precessing, and turning on and off episodically. This color picture, taken with the Wide Field Planetary Camera-2, is a composite of three images taken at different wavelengths. (red, hydrogen-alpha; blue, neutral oxygen, 6300 angstroms; green, ionized nitrogen, 6584 angstroms). The image was taken on September 18, 1994. NGC 6543 is 3,000 light- years away in the northern constellation Draco. The term planetary nebula is a misnomer; dying stars create these cocoons when they lose outer layers of gas. The process has nothing to do with planet formation, which is predicted to happen early in a star's life.

1994-01-01

304

Dose effects of gamma radiation sterilization on antibiotic eye ointment  

International Nuclear Information System (INIS)

Radiation effects of Co-60 gamma rays on some eye ointment base such as plastibase, cetyl alcohol, liquid paraffin, vaselin album, adeps lanae and tetracycline eye ointment in plastibase were examined by physico-chemical determinations. Parameters observed were color changes, pH, melting point, viscosity, iodine value, acid value and TLC, uv-spectrophotometric examination. Microbiological examinations were carried out to determine the degree of initial contamination of unirradiated eye ointment. Radiation dose used were radiation sterilization doses of 2 and 4 Mrad and storage time was 3 and 6 months. The results showed that the iodine value of tetracycline eye ointment in plastibase and eye ointment bases such as plastibase, vaselin album, liquid paraffin, cetyl alcohol, adeps lanae, changed significantly. Viscosity examination showed non-significant results, except for vaselin album and liquid paraffin irradiated at 4 Mrad. Microbiological examinations showed that some unirradiated eye ointment were contaminated by a few kinds of microbes. (author)

305

Diabetes - Eye Complications  

Medline Plus

Full Text Available ... can be prevented or delayed through good diabetes management. When they occur, these diseases can be treated ... as retinopathy, cataract, and glaucoma. Prevention through successful management of diabetes helps prevent and delay these eye ...

306

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... and prevent the patient from blinking. A suction ring placed on the eye lifts and flattens the ... feel pressure from the eyelid holder and suction ring, similar to a finger pressed firmly on the ...

307

Multimodal eye recognition  

Science.gov (United States)

Multimodal biometrics use more than one means of biometric identification to achieve higher recognition accuracy, since sometimes a unimodal biometric is not good enough used to do identification and classification. In this paper, we proposed a multimodal eye recognition system, which can obtain both iris and sclera patterns from one color eye image. Gabor filter and 1-D Log-Gabor filter algorithms have been applied as the iris recognition algorithms. In sclera recognition, we introduced automatic sclera segmentation, sclera pattern enhancement, sclera pattern template generation, and sclera pattern matching. We applied kernelbased matching score fusion to improve the performance of the eye recognition system. The experimental results show that the proposed eye recognition method can achieve better performance compared to unimodal biometric identification, and the accuracy of our proposed kernel-based matching score fusion method is higher than two classic linear matching score fusion methods: Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA).

Zhou, Zhi; Du, Yingzi; Thomas, N. L.; Delp, Edward J., III

2010-04-01

308

Patient Eye Examinations - Adults  

Science.gov (United States)

... Preparing for Laser Surgery Fundus Photographs Using a Phoropter Using a direct ophthalmoscope Eye Care Consultation Determining a patient’s eyeglass prescription Using a Phoropter Using a Slit Lamp Photographing the Retina NEI ...

309

What Is Dry Eye?  

Medline Plus

Full Text Available ... purpose. The oily layer, produced by the meibomian glands, forms the outermost surface of the tear film. ... as tears. This layer, produced by the lacrimal glands in the eyelids, cleanses the eye and washes ...

310

What Is Dry Eye?  

Medline Plus

Full Text Available ... Answers Search QA Browse all answered questions > Related Resources Related Topics Six Smart Things College Students Should ... privacy policy sponsorship & advertising policies about us Educational Resources EyeWiki contact us sitemap Reproducing text or images ...

311

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... to six months after LASIK surgery for the improvements in a person's vision to fully stabilize and ... Eye M.D. the benefits and risks — including quality of life issues — that could result from correcting ...

312

Eye Injuries at Work  

Science.gov (United States)

... Occupational Safety and Health Administration (OSHA) reports that workplace eye injuries cost an estimated $300 million a year in lost productivity, medical treatment and worker compensation . The most important ...

313

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... LASIK Surgery: Why All Patients Need the K Card (PDF 650K) If you have decide to have ... later, such as cataract surgery. Bring this "K Card" with you to your Eye M.D. appointment ...

314

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... risk for developing eye diseases or conditions themselves. Sleep Apnea and Glaucoma Research shows that those with ... the overall complication rate is low. Infection and inflammation are possibilities, as with any surgical procedure, and ...

315

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... Enter your question here... Browse Top Answers > Privacy Policy > Featured Video LASIK (Femtosecond) 0:50 Free Newsletter ... about eye health and preserving your vision. Privacy Policy Email address

316

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... detailed 20/20 vision is essential for your job or leisure activities, consider whether 20/40 vision ... An Eye M.D. Enter zip code here Search by Name, City, State or Subspecialty > Ask An ...

317

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... risk for developing eye diseases or conditions themselves. Sleep Apnea and Glaucoma Research shows that those with sleep apnea are more likely to develop glaucoma. Get treated ...

318

Diabetes - Eye Complications  

Medline Plus

Full Text Available ... Diabetic Retinopathy The best treatment for retinopathy is prevention. Good control of blood sugar level and blood ... eye problems such as retinopathy, cataract, and glaucoma. Prevention through successful management of diabetes helps prevent and ...

319

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... infection and permanent loss of your eyelashes. What Is an Ophthalmologist? Make sure you are seeing the ... You Fit at 40? A baseline eye exam is recommended at age 40, when the signs of ...

320

What Is Dry Eye?  

Medline Plus

Full Text Available ... Reduced Vision Tearing See all Symptoms > Glasses, Contacts & LASIK Contact Lenses Colored Contact Lenses Eyeglasses IOLs Refractive Surgery & LASIK Sunglasses Living EyeSmart About Ophthalmologists Adults Under 40 ...

 
 
 
 
321

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... Get treated to save your sight. What Is an Ophthalmologist? Make sure you are seeing the right ... lenses. Next Page: Alternative Refractive Surgery Procedures Find An Eye M.D. Enter zip code here Search ...

322

Diabetes - Eye Complications  

Medline Plus

Full Text Available ... have other eye problems such as blurred vision, cataract, and glaucoma. People with diabetes may have blurry ... is back to normal. All people can get cataract, especially when they get older. However, diabetic patients ...

323

Therapy of Eye Cancer  

International Science & Technology Center (ISTC)

Development and Creation of New Forms of Ophthalmology b - Applicators for Radiation Therapy of Eye Cancer and Study of Psycho-Physiological Effects on Man of Low Frequency Electromagnetic Radiation Emitted by Radio Nuclides.

324

Eye banking: an introduction  

Directory of Open Access Journals (Sweden)

Full Text Available This article introduces the work of eye banks, institutions responsible for collecting (harvesting and processing donor corneas, and for distributing them to trained corneal graft surgeons.

Gullapalli N Rao

2009-12-01

325

Diabetes - Eye Complications  

Medline Plus

Full Text Available ... back of the eye is known as the retina. The retina changes light signals into electric signals, sent through ... images we see. The central part of the retina is known as the “macula” and is responsible ...

326

What Is Dry Eye?  

Medline Plus

Full Text Available ... information about eye health and preserving your vision. Privacy Policy Email address © 2014 American Academy of Ophthalmology medical disclaimer privacy policy sponsorship & advertising policies about us Educational Resources ...

327

LASIK - Laser Eye Surgery  

Medline Plus

Full Text Available ... D. Enter your question here... Browse Top Answers > Privacy Policy > Featured Video LASIK (Femtosecond) 0:50 Free ... information about eye health and preserving your vision. Privacy Policy Email address

328

Unusual eye injuries  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The analysis of ten unusual eye injuries, and the discussion of appropriate preventive measures. Case outline: Ten patients hospitalized at the Clinic of Eye Diseases, Clinical Center of Serbia, Belgrade, in the period from January 2000. to December 2009. were presented. Following data were taken in account: sex and age of the patient, injured eye, the mechanism of injury, type of the injury, applied treatment and final visual acuity. The circumstances of the eye injuring of ten patients were described. The eye injuries in all cases occurred in a bizarre way and they were severe enough to require hospital admission. The surgery was necessary in seven patients. Three injured eyes resulted in blindness, and two additional had subnormal vision. Conclusion: In three quarters of discussed cases injuries can be avoided. It is necessary to implement protective measures constantly and consistently and to think about the possible consequences of certain activities. Particular attention should be paid on safety of children. The iatrogenic injuries require special consideration.

Jovanovi? Miloš

2012-01-01

329

AN INNER STRUGGLE: UNDER WESTERN EYES  

Directory of Open Access Journals (Sweden)

Full Text Available This study aims to shed light on the most significant aspect of the modern man’s inner struggle in Joseph Conrad’s Under Western Eyes. Joseph Conrad is one of the authors of the twentieth century who was influenced by the psychological philosophy and he makes use of this influence in his works deeply. He who synthesizes the inner nature of the modern man, having conflicts himself with the deeper analysis field of the psychology aims to point out the incomprehensible and unsettled inner nature of the modern man in Under Western Eyes.

Hale Ya?l?dere

2013-06-01

330

Selecting PPE for the Workplace (Personal Protective Equipment for the Eyes and Face)  

Science.gov (United States)

... Small Business Anti-Retaliation eTools Home : Eye and Face Protection Scope | FAQs | Glossary | Additional References | Credits PPE ... Personal protective equipment (PPE) for the eyes and face is designed to prevent or lessen the severity ...

331

Are 3-D Movies Bad for Your Eyes?  

Medline Plus

Full Text Available ... D Movies Bad for Your Eyes? Tweet Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During ... Eye Protection Eyesight Risks for Smokers Veterans & Eye Health More Lifestyle Topics > EyeSmart Tips Eye Protection at ...

332

Identification system by eye retinal pattern  

International Nuclear Information System (INIS)

Identification system by eye retinal pattern is introduced from the view-point of history of R and D, measurement, apparatus, evaluation tests, safety and application. According to our evaluation tests, enrolling time is approximately less than 1 min, verification time is a few seconds and false accept rate is 0 %. Evaluation tests at Sandia National Laboratories in USA show the comparison data of false accept rates such as 0 % for eye retinal pattern, 10.5 % for finger-print, 5.8 % for signature dynamics and 17.7 % for speaker voice. The identification system by eye retinal pattern has only three applications in Japan, but there has been a number of experience in USA. This fact suggests that the system will become an important means for physical protections not only in nuclear field but also in other industrial fields in Japan. (author)

333

Effect of Education Sessions of a Structured School Eye Screening Programme on Indian Schoolteachers' Knowledge and Responsibility for Children's Eye Health  

Science.gov (United States)

Objective: To evaluate the effect of education sessions on Indian schoolteacher awareness of childhood eye health issues, responsibility for children's eye health, and successful participation in a teacher-led eye screening health intervention programme in primary schools aimed at addressing avoidable childhood blindness in India. Design:…

Thummalapalli, Rohit; Williams, Jachin D.; Khoshnood, Kaveh; Salchow, Daniel J.; Forster, Susan H.

2013-01-01

334

Genetic analyses of the human eye colours using a novel objective method for eye colour classification  

DEFF Research Database (Denmark)

In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically identified and extracted from high resolution digital images. DIAT was made user friendly with a graphical user interface. The software counted the number of blue and brown pixels in the iris image and calculated a Pixel Index of the Eye (PIE-score) that described the eye colour quantitatively. The PIE-score ranged from -1 to 1 (brown to blue). The software eliminated the need for user based interpretation and qualitative eye colour categories. In 94% (570) of 605 analyzed eye images, the iris region was successfully extracted and a PIE-score was calculated. A very high correlation between the PIE-score and the human perception of eye colour was observed. The correlations between the PIE-scores and the six IrisPlex SNPs (HERC2 rs12913832, OCA2 rs1800407, SLC24A4 rs12896399, TYR rs1393350, SLC45A2 rs16891982 and IRF4 rs12203592) were analyzed in 570 individuals. Significant differences (p

Andersen, Jeppe D; Johansen, Peter

2013-01-01

335

Wheelchair Motion Control Guide Using Eye Movement Based on EEG Signals.  

Directory of Open Access Journals (Sweden)

Full Text Available The design and implementation of an Autonomous Movement Robot based on a Wheelchair based on EOG signal is to help a disable or handicapped person. These EOG electrodes are placed at right and left of eye and other pair of electrodes are at top and right of the eye. These electrodes used to response after gazing of one target point for a particular time period. After gazing of point, the wheelchair used to move to a target position. So, it produce delay during eye gaze. To overcome this delay, EEG amplifier are used. These EEG signals are placed to capture brain waves. These brain waves are controlled by microcontroller and it produce analog waves. To convert analog waves to digital output Analog to digital converter is used. Object Sensor is used to avoid obstacles in its path respectively. The main contribution of the work is the combination of several technologies and techniques that came from different areas such as mechanical, electronic engineering. Driver circuit with relay are used to move wheelchair automatically. ZigBee is used for long transmission of wheelchair. Accelerometer and interfacing circuit are done by using head movement. DLOA algorithm used to avoid obstacles while reaching destination point. The target coordinates of the destination place using EEG, to reduce delay for auto navigation process.

D.Uma Mageswar

2013-05-01

336

Eye contact in medical examinations using videophones.  

Science.gov (United States)

In Japan, approximately 12,000,000 cellular phones with a videophone function have been distributed and are becoming an important part of the telemedicine infrastructure. By eye movement analysis, we investigated the effectiveness of eye contact using cellular videophones during medical interviews. Three male volunteers acted as first-time patients and were filmed using a high-resolution camera. The video of each of these volunteers was converted into pictures of three different sizes-70 cm x 40 cm (large picture), 26 cm x 20 cm (medium picture), and 14 cm x 12 cm (small picture)-and viewed on a 32-inch video monitor. The large, medium, and small pictures were considered to represent an actual medical interview, an interview via a television conference system, and an interview via a cellular videophone, respectively. Nine doctors watched these pictures, and their eye movements were recorded with a gaze-point recorder. After watching the videos, the doctors evaluated quality of three size pictures. Standard deviation values of the gaze point coordinates decreased with the picture size. However, a very low decrease was observed in the time ratio, during which the gaze point was on the face (eye contact rate); the rate was 92.2% (large picture), 91.8% (medium picture), and 85.1% (small picture). No statistical difference was observed between the values of the medium and small pictures. Subjective evaluations yielded low scores in the small pictures. The relatively high rate of eye contact rate in the small pictures suggests that a cellular videophone will be a good tool for telemedicine, although the usage by which the subjective evaluations can be improved should be determined by doctors. PMID:17042706

Suzuki, Toshiro; Murase, Sumio; Kitano, Akihiko; Nagase, Hiroaki; Momoi, Sadayoshi; Nakamaki, Makoto

2006-10-01

337

Influences of reference plane and direction of measurement on eye aberration measurement  

Science.gov (United States)

We explored effects of measurement conditions on wave aberration estimates for uncorrected, axially myopic model eyes. Wave aberrations were initially referenced to either the anterior corneal pole or the natural entrance pupil of symmetrical eye models, with rays traced into the eye from infinity (into the eye) to simulate normal vision, into the eye from infinity and then back out of the eye from the retinal intercepts (into/out of the eye), or out of the eye from the retinal fovea (out of the eye). The into-the-eye and out-of-the-eye ray traces gave increases in spherical aberration as myopia increased, but the into/out-of-the-eye ray trace showed little variation in spherical aberration. Reference plane choice also affected spherical aberration. Corresponding residual aberrations were calculated after the models had been optically corrected, either by placing the object or image plane at the paraxial far point or by modifying corneas to simulate laser ablation corrections. Correcting aberrations by ablation was more complete if the original aberrations were referenced to the cornea rather than to the entrance pupil. For eyes corrected by spectacle lenses, failure to allow for effects of pupil magnification on apparent entrance pupil diameter produced larger changes in measured aberrations. The general findings regarding choice of reference plane and direction of measurement were found to be equally applicable to eyes that lacked rotational symmetry.

Atchison, David A.; Charman, W. Neil

2005-12-01

338

How could complex eyes have evolved?  

Science.gov (United States)

This analysis and discussion activity introduces students to evidence from comparative anatomy, mathematical modeling, and DNA analysis. This evidence suggests a sequence of steps that appear to have contributed to the evolution of the human eye. Questions in the Student Handout guide students in analyzing this evidence, evaluating whether the similarities between human and octopus eyes are due to convergent evolution and/or common descent with modification, and understanding the role of gene duplication in evolution. This activity is designed to help high school students meet the Next Generation Science Standards and the Common Core State Standards.

Waldron, Ingrid

339

Game Design and Homemade PowerPoint Games: An Examination of the Justifications and a Review of the Research  

Science.gov (United States)

Research on educational games often focuses on the benefits that playing games has on student achievement. However, there is a growing body of research examining the benefits of having students design games rather than play them. Problems with game design as an instructional tool include the additional instruction on the programming language…

Siko, Jason; Barbour, Michael

2013-01-01

340

Eye-Tracking.  

Science.gov (United States)

Reviews the eye-movement paradigm and refers to recent experiments applying the paradigm to issues of spoken word recognition (e.g., lexical competitor effects), syntactic processing, reference resolution, focus, as well as issues in cross-modality integration that are central to evaluating the modularity hypothesis. (Seven references) (Author/CK)

Tanenhaus, Michael K.; Spivey-Knowlton, Michael J.

1996-01-01

 
 
 
 
341

Eye Disease and Development  

DEFF Research Database (Denmark)

This research advances the hypothesis that cross-country variation in the historical incidence of eye disease has influenced the current global distribution of per capita income. The theory is that pervasive eye disease diminished the incentive to accumulate skills, thereby delaying the fertility transition and the take-off to sustained economic growth. In order to estimate the influence from eye disease incidence empirically, we draw on an important fact from the field of epidemiology: Exposure to solar ultraviolet B radiation (UVB-R) is an underlying determinant of several forms of eye disease; the most important being cataract, which is currently the leading cause of blindness worldwide. Using a satellite-based measure of UVB-R, we document that societies more exposed to UVB-R are poorer and underwent the fertility transition with a significant delay compared to the forerunners. These findings are robust to the inclusion of an extensive set of climate and geography controls. Moreover, using a global data set on economic activity for all terrestrial grid cells we show that the link between UVB-R and economic development survives the inclusion of country fixed effect.

Andersen, Thomas Barnebeck; Dalgaard, Carl-Johan Lars

2011-01-01

342

Healthy Eyes, Healthy Body  

Science.gov (United States)

... grow up healthier and able to pursue their dreams. Through Let’s Move! Museums & Gardens , the Museum of Vision joins thousands of institutions all over the United States helping young people learn about how food choices and physical activity affect their health – including their eye health. Find out ...

343

Diabetes - Eye Complications  

Medline Plus

Full Text Available ... Plain.com db010105 Last reviewed: 11/29/2012 1 Diabetic Retinopathy Patients with diabetes are more likely to develop eye problems. Insulin ... patients may get cataract earlier than people without diabetes. Clouding of the ... cataract. The symptom of cataract is blurred vision. Cataract can be ...

344

On the use of schematic eye models to estimate retinal image quality  

Science.gov (United States)

The optical performance of the eyes of nine vertebrate species was evaluated using optical system design techniques and schematic eye models. Essential features of eyes, including the modulation transfer function (MTF) and the MTF cutoff frequency are related to the numerical aperture of the eyes. Superior resolution for in vivo imaging of photoreceptors may be achieved by dilating the iris pupil of an eye, minimizing coherence, and using short wavelength illumination. The difference of lateral and axial resolution between a small and a large eye for imaging photoreceptors in vivo.

Li, Guo; Zwick, Harry; Stuck, Bruce E.; Lund, David J.

2000-07-01

345

Gaze estimation for off-angle iris recognition based on the biometric eye model  

Science.gov (United States)

Iris recognition is among the highest accuracy biometrics. However, its accuracy relies on controlled high quality capture data and is negatively affected by several factors such as angle, occlusion, and dilation. Non-ideal iris recognition is a new research focus in biometrics. In this paper, we present a gaze estimation method designed for use in an off-angle iris recognition framework based on the ORNL biometric eye model. Gaze estimation is an important prerequisite step to correct an off-angle iris images. To achieve the accurate frontal reconstruction of an off-angle iris image, we first need to estimate the eye gaze direction from elliptical features of an iris image. Typically additional information such as well-controlled light sources, head mounted equipment, and multiple cameras are not available. Our approach utilizes only the iris and pupil boundary segmentation allowing it to be applicable to all iris capture hardware. We compare the boundaries with a look-up-table generated by using our biologically inspired biometric eye model and find the closest feature point in the look-up-table to estimate the gaze. Based on the results from real images, the proposed method shows effectiveness in gaze estimation accuracy for our biometric eye model with an average error of approximately 3.5 degrees over a 50 degree range.

Karakaya, Mahmut; Barstow, Del; Santos-Villalobos, Hector; Thompson, Joseph; Bolme, David; Boehnen, Christopher

2013-05-01

346

Gaze Estimation for Off-Angle Iris Recognition Based on the Biometric Eye Model  

Energy Technology Data Exchange (ETDEWEB)

Iris recognition is among the highest accuracy biometrics. However, its accuracy relies on controlled high quality capture data and is negatively affected by several factors such as angle, occlusion, and dilation. Non-ideal iris recognition is a new research focus in biometrics. In this paper, we present a gaze estimation method designed for use in an off-angle iris recognition framework based on the ANONYMIZED biometric eye model. Gaze estimation is an important prerequisite step to correct an off-angle iris images. To achieve the accurate frontal reconstruction of an off-angle iris image, we first need to estimate the eye gaze direction from elliptical features of an iris image. Typically additional information such as well-controlled light sources, head mounted equipment, and multiple cameras are not available. Our approach utilizes only the iris and pupil boundary segmentation allowing it to be applicable to all iris capture hardware. We compare the boundaries with a look-up-table generated by using our biologically inspired biometric eye model and find the closest feature point in the look-up-table to estimate the gaze. Based on the results from real images, the proposed method shows effectiveness in gaze estimation accuracy for our biometric eye model with an average error of approximately 3.5 degrees over a 50 degree range.

Karakaya, Mahmut [ORNL; Barstow, Del R [ORNL; Santos-Villalobos, Hector J [ORNL; Thompson, Joseph W [ORNL; Bolme, David S [ORNL; Boehnen, Chris Bensing [ORNL

2013-01-01

347

People with Increased Risk of Eye Damage from UV Light  

Science.gov (United States)

... Computer Usage Diabetes Diet & Nutrition Eye Injuries Eye Screening Guidelines Home Remedies for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye ...

348

A point model for the design of a sulfur trioxide decomposer for the SI cycle and comparison with a CFD model  

Energy Technology Data Exchange (ETDEWEB)

Operating under the harsh environment with the significant energy consumption, the sulfur trioxide decomposer is one of the most important components, yet challenging tasks for the designers of an efficient SI cycle. We developed a point model to provide important guidelines for designers of a sulfur trioxide decomposer through estimating outlet physical quantities, such as outlet decomposition ratio, outlet temperature, and pressure drop of a sulfur trioxide decomposer. Then, results of the point model were compared to independent predictions obtained using a CFD model over a wide range of conditions with good agreement. The model indicates that decomposition ratio is a function of the representative non-dimensional design parameter and inlet flow composition. As inlet flow composition rarely affects outlet decomposition ratio, we found out that outlet decomposition ratio can be approximated solely as a function of the non-dimensional design parameter. We demonstrated that the model can provide general guidelines for designers of a sulfur trioxide decomposer to achieve a target decomposition ratio with an economical design. It turns out that an increase in operating pressure and catalyst surface area leads to an increase in outlet decomposition ratio while the reverse is true for an increase in mass flow rate. (author)

Lee, You Ho; Lee, Jeong Ik; No, Hee Cheon [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea)

2010-06-15

349

Disability: recommendations for eye programmes  

Directory of Open Access Journals (Sweden)

Full Text Available In 2012, CBM’s Medical Eye Care Advisory Working Group met in Hyderabad, India to discuss the inclusion of people with disabilities in eye care.As a result of these discussions, recommendations were made.

2013-05-01

350

If I Had - Dry Eyes  

Medline Plus

Full Text Available ... with Severe COPD VIDEO: If I Had - Dry Eyes - Dr. Penny Asbell, MD, FACS, MBA, Professor of ... to Home Page VIDEO: If I Had - Dry Eyes - Dr. Penny Asbell, MD, FACS, MBA, Professor of ...

351

Protecting Your Eyes at Work  

Science.gov (United States)

... Eyes at Work Protecting Your Eyes at Work Computer Vision Syndrome Guidelines for The Use of Contact ... infrared radiation exposure, and flying wood or metal chips. In addition, health care workers, laboratory and janitorial ...

352

Organizing design activities associated with Instrumentation and Control system upgrading at an operating WWER type nuclear power plant: General Designer's point of view  

International Nuclear Information System (INIS)

Some problems that the company Energoprojekt as the General Designer encountered when setting up the basic design for replacement of the Instrumentation and Control (I and C) Systems in the nuclear power plants at Mochovce in Slovakia and Temelin in the Czech Republic are highlighted. The possibility of making use of the experience when organizing other design activities associated with I and C system replacement is discussed. Although the two NPPs are undergoing I and C system replacement prior to their commissioning, the company can benefit from the experience when organizing design activities for I and C system replacement at operating WWERs as well

353

The HTR-2 modular nuclear power plant. Evaluation of the design concept from the point of view of safety engineering  

International Nuclear Information System (INIS)

The summary report presents the safety engineering aspects of a HTR design concept with two modules for cogeneration of electricity and process heat, or district heat, respectively. The evaluation is based on a complete and representative list of design-basis accidents, and from the subsequent accident analyses, design criteria and requirements are derived for all plant components and systems. The analyses also yield information on representative radiological events and conditions. The results show that the radioactivity release due to specified normal operation will keep the radiation dose to the environment below the limits defined in section 45 of the Radiation Protection Ordinance (StrlSchVO). (DG)

354

A nanoparticle formulation reduces the corneal toxicity of indomethacin eye drops and enhances its corneal permeability.  

Science.gov (United States)

Indomethacin (IMC) has been shown to reduce post-operative inflammation and to decrease intraocular irritation after cataract extraction and in cystoid macular edema; however, the clinical use of its most commonly used eye drops is limited due to topical side-effects that include burning sensation, irritation and epithelial keratitis. It is known that decreasing direct cell stimulation and reducing the amount applied via increasing bioavailability are useful for improving these issues. In this study, we designed ophthalmic formulations containing 0.5% IMC nanoparticles using zirconia beads and Bead Smash 12 (IMCnano eye drops; particle size 76 ± 59 nm, mean ± S.D.), and investigated the corneal toxicity of these IMCnano eye drops. IMCnano eye drops are tolerated better by a human cornea epithelial cell line (HCE-T) than commercially available NDSAIDs preparations (IMC, pranoprofen, diclofenac, bromfenac and nepafenac eye drops), and corneal wound healing in rat eyes with debrided corneal epithelium instilled with IMCnano eye drops is significantly better than that of eyes instilled with commercially available IMC eye drops. In addition, the accumulation of IMC in HCE-T cells treated with the IMCnano eye drops for 30 min was 19.9% that of the accumulation from commercially available IMC eye drops. On the other hand, the corneal penetration of IMC from IMCnano eye drops was significantly greater than in the case of the commercially available IMC eye drops in both in vivo and in vitro studies using rabbit corneas. Taken together, we hypothesize that a nanoparticle formulation reduces the corneal toxicity of IMC eye drops, probably because the accumulation of IMC from IMCnano eye drops in the eye is lower than that from commercially available IMC eye drops. In addition, the nanoparticle formulation may allow a decrease in the amount of IMC used due to the increase in bioavailability, resulting in reduced drug toxicity. These findings provide significant information that can be used to design further studies aimed at developing less toxic eye drops. PMID:24598350

Nagai, Noriaki; Ito, Yoshimasa; Okamoto, Norio; Shimomura, Yoshikazu

2014-05-01

355

78 FR 71621 - Agency Information Collection Activities; Proposed Collection; Comment Request; Eye Tracking...  

Science.gov (United States)

...comments on research entitled, ``Eye Tracking Study of Direct-to-Consumer...This study is designed to use eye tracking technology to explore...or provide information to a third party. Section 3506(c...forms of information technology. Eye Tracking Study of...

2013-11-29

356

42 CFR 485.643 - Condition of participation: Organ, tissue, and eye procurement.  

Science.gov (United States)

...participation: Organ, tissue, and eye procurement. 485.643 Section...participation: Organ, tissue, and eye procurement. The CAH must...timely manner, the OPO or a third party designated by the OPO...medical suitability for tissue and eye donation, using the...

2010-10-01

357

42 CFR 482.45 - Condition of participation: Organ, tissue, and eye procurement.  

Science.gov (United States)

...participation: Organ, tissue, and eye procurement. 482.45 Section...participation: Organ, tissue, and eye procurement. (a) Standard...timely manner, the OPO or a third party designated by the OPO...medical suitability for tissue and eye donation, using the...

2010-10-01

358

Enhancing eye donation rates. Training students to be motivators  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Medical professionals could enhance eye donation rates by reminding relatives during grief counseling at the time of patient?s death. This study was designed to assess the knowledge and attitudes of final year medical students (future doctors towards eye donation, prior to instruction in eye banking. Methods: The responses of 49 final-year medical students to a questionnaire on eye donation were compared with 24 non-medical students (controls. The results were analysed statistically using the chi-square test. Results: More than one-third of students and controls were unaware that eyes are removed within six hours of death. Eight (16.3% students and 6 (25.0% controls felt that a close relative?s eyes could be donated after death only if he had indicated willingness (P=0.05. Three (6.1% students and 3 (12.5% controls were undecided about donating their own eyes. Nineteen (38.8% students and 6 (25% controls did not know where to go in order to pledge/donate eyes. The controls had poorer knowledge of ocular and systemic contraindications, and they did not know that storage could be prolonged (PConclusions: Controls were poorly informed about various aspects of eye donation suggesting inadequate dissemination of information by the media. Students and controls alike had misconceptions regarding donation of relatives? eyes and hesitation regarding their own. These aspects should be emphasized during undergraduate teaching to dispel misgivings regarding wastage of donor eyes and to encourage future doctors to promote eye donation.

Dhaliwal Upreet

2002-01-01

359

Combining head pose and eye location information for gaze estimation.  

Science.gov (United States)

Head pose and eye location for gaze estimation have been separately studied in numerous works in the literature. Previous research shows that satisfactory accuracy in head pose and eye location estimation can be achieved in constrained settings. However, in the presence of nonfrontal faces, eye locators are not adequate to accurately locate the center of the eyes. On the other hand, head pose estimation techniques are able to deal with these conditions; hence, they may be suited to enhance the accuracy of eye localization. Therefore, in this paper, a hybrid scheme is proposed to combine head pose and eye location information to obtain enhanced gaze estimation. To this end, the transformation matrix obtained from the head pose is used to normalize the eye regions, and in turn, the transformation matrix generated by the found eye location is used to correct the pose estimation procedure. The scheme is designed to enhance the accuracy of eye location estimations, particularly in low-resolution videos, to extend the operative range of the eye locators, and to improve the accuracy of the head pose tracker. These enhanced estimations are then combined to obtain a novel visual gaze estimation system, which uses both eye location and head information to refine the gaze estimates. From the experimental results, it can be derived that the proposed unified scheme improves the accuracy of eye estimations by 16% to 23%. Furthermore, it considerably extends its operating range by more than 15° by overcoming the problems introduced by extreme head poses. Moreover, the accuracy of the head pose tracker is improved by 12% to 24%. Finally, the experimentation on the proposed combined gaze estimation system shows that it is accurate (with a mean error between 2° and 5°) and that it can be used in cases where classic approaches would fail without imposing restraints on the position of the head. PMID:21788191

Valenti, Roberto; Sebe, Nicu; Gevers, Theo

2012-02-01

360

Conjunctivitis (Pink Eye) in Newborns  

Science.gov (United States)

... eye drops, such as erythromycin. To treat infection, topical antibiotic eye drops and ointments, oral antibiotics, and intravenous (given through a vein) antibiotics are all used, depending on the severity of ... responsible for it. Topical (applied to the eye) and oral or topical ...

 
 
 
 
361

Eye-Openers in ASL.  

Science.gov (United States)

This paper summarizes most of what Sign linguists know about the function of the eyes in American Sign Language discourse. Here, "eyes" is taken to cover both opening and closing of the eyes and looking in a particular direction, referred to as the signer's "gaze-direction." Evidence is presented demonstrating that a signer's gaze can be lexically…

Baker, Charlotte

362

Eye Pupil Location Using Webcam  

CERN Document Server

Three different algorithms used for eye pupil location were described and tested. Algorithm efficiency comparison was based on human faces images taken from the BioID database. Moreover all the eye localisation methods were implemented in a dedicated application supporting eye movement based computer control. In this case human face images were acquired by a webcam and processed in a real-time.

Ciesla, Michal

2012-01-01

363

Are 3-D Movies Bad for Your Eyes?  

Medline Plus

Full Text Available ... D Movies Bad for Your Eyes? Tweet Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During ... Eye Protection Eyesight Risks for Smokers Veterans & Eye Health More Lifestyle Topics > EyeSmart Tips Blood Sugar and ...

364

Are 3-D Movies Bad for Your Eyes?  

Medline Plus

Full Text Available ... Bad for Your Eyes? Tweet Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During Pregnancy Computer ... Risks for Smokers Veterans & Eye Health More Lifestyle Topics > EyeSmart Tips Blood Sugar and Eye Exams Control ...

365

Are 3-D Movies Bad for Your Eyes?  

Medline Plus

Full Text Available ... Bad for Your Eyes? Tweet Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During Pregnancy Computer ... Risks for Smokers Veterans & Eye Health More Lifestyle Topics > EyeSmart Tips Eye Protection at Home Every household ...

366

Are 3-D Movies Bad for Your Eyes?  

Medline Plus

Full Text Available ... D Movies Bad for Your Eyes? Tweet Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During ... Eye Protection Eyesight Risks for Smokers Veterans & Eye Health More Lifestyle Topics > EyeSmart Tips Opening Champagne Bottles ...

367

The software design of multi-branch, multi-point remote monitoring system for temperature measurement based on MSP430 and DS18B20  

International Nuclear Information System (INIS)

This paper present that the system can acquire the remote temperature measurement data of 40 monitoring points, through the RS-232 serial port and the Intranet. System's hardware is consist of TI's MSP430F149 mixed-signal processor and UA7000A network module. Using digital temperature sensor DS18B20, the structure is simple and easy to expand, the sensors directly send out the temperature data, MSP430F149 has the advantage of ultra-low-power and high degree of integration. Using msp430F149, the multi-branch multi-point temperature measurement system is powerful, simple structure, high reliability, strong anti-interference capability. The client software is user-friendly and easy to use, it is designed in Microsoft Visual C+ +6.0 environment. The monitoring system is able to complete a total of 4 branches of the 40-point temperature measurements in real-time remote monitoring. (authors)

368

What Is a Comprehensive Dilated Eye Exam?  

Science.gov (United States)

... de Escuchar . What is a comprehensive dilated eye exam? A comprehensive dilated eye exam is a painless ... your best. What does a comprehensive dilated eye exam include? A comprehensive eye examination includes: dilation , tonometry , ...

369

Eye Health in Sports and Recreation  

Science.gov (United States)

... Eye Health News Consumer Alerts Eye Health in Sports and Recreation Tweet Tens of thousands of sports ... Eye Injuries in American Sports History High-Risk Sports For all age groups, sports-related eye injuries ...

370

Technical evaluation of the electrical, instrumentation, and control design aspects of the low temperature overpressure protection system for the Point Beach Nuclear Power Plant, Units 1 and 2  

International Nuclear Information System (INIS)

The technical evaluation is presented for the electrical, instrumentation, and control design aspects of the low temperature overpressure protection system for the Point Beach nuclear power plant, Units 1 and 2. Design basis criteria used to evaluate the acceptability of the system included operator action, system testability, single failure criterion, and seismic Category I and IEEE Std-279-1971 criteria. This report is supplied as part of the Selected Electrical, Instrumentation, and Control Systems Issues Support Program being conducted for the U.S. Nuclear Regulatory Commission by Lawrence Livermore Laboratory

371

Technical evaluation of the electrical, instrumentation, and control design aspects of the low temperature overpressure protection system for the Point Beach Nuclear Power Plant, Units 1 and 2  

Energy Technology Data Exchange (ETDEWEB)

The technical evaluation is presented for the electrical, instrumentation, and control design aspects of the low temperature overpressure protection system for the Point Beach nuclear power plant, Units 1 and 2. Design basis criteria used to evaluate the acceptability of the system included operator action, system testability, single failure criterion, and seismic Category I and IEEE Std-279-1971 criteria. This report is supplied as part of the Selected Electrical, Instrumentation, and Control Systems Issues Support Program being conducted for the U.S. Nuclear Regulatory Commission by Lawrence Livermore Laboratory.

Laudenbach, D.H.

1979-03-01

372

Development of an optical simulator of the human eye  

Science.gov (United States)

The optics of the human eye have for several years been the subject of careful physiological study. This study has led to the development of models characterizing its operation and allowed to predict its behavior. In general, these models are based on empirical data derived from statistical studies on specific populations. At the same time, different optical analysis techniques are being developed in order to study the eye. These techniques are based on projecting light into the eye or in using optical systems to observe the eye. Thus, it becomes important to have tools to simulate the human eye during the development of these techniques prior to its implementation using human subjects. Several simulators have been developed based on existing models, many of them using ZEMAX optical design program. However, in general, their use has been limited to simple models and/or dedicated analysis. However, the appearance of a toolbox that allows the programming software MatLab to command the optical design program opened a new range of control and analysis capabilities for systems modeled in ZEMAX. Using these tools, a dynamic simulator was developed that allows the user to optically characterize an eye based on age and distance to an object being observed accordingly with one existing model. The capabilities of both programs allowed obtaining a tool capable of not only helping the development of optical analysis techniques but also be used in developing new eye models or analyze eye safety issues. Its performance is presented and analysis examples shown.

Coelho, João. M. P.; Baião, André; Vieira, Pedro

2013-11-01

373

Design and fabrication of a miniaturization micro volume auto titrator coupled with electrochemical end-point detector for the determination of acidity of some fruit juice  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A miniaturization micro volume auto titrator coupled with electrochemical end-point detector was designed and fabricated for the determination of acidity of some Thai citrus fruit juices collected in the northern area of Thailand. The method was based on on-line potentiometric titration of the acid contents with sodium hydroxide. Conditions such as volume of fruit juice sample, volume and concentration of potassium chloride used as supporting electrolyte and flow rate of titrant were optimize...

Prinya Masawat

2008-01-01

374

Comparison of eye shields in radiotherapeutic beams  

International Nuclear Information System (INIS)

Full text: Both MeV electrons and kV photons are used in the treatment of superficial cancers. The advantages and disadvantages for each of these modalities have been widely reported in the literature (See for example [1-2]). Of particular note in the literature is the use of lead and tungsten eye shields to protect ocular structures during radiotherapy. An investigation addressing issues raised in the literature that are relevant to the Wellington Cancer Centre method of treatment of lesions near the eye shall be summarised. Various small sized fields were irradiated to determine depth dose and profile curves in a water phantom shielded by various commercially available eye shields. Transmission factors relevant to critical ocular structures and particle distribution theories are used to further elucidate the comparison between the use of MeV electrons and kV photons in the treatment of superficial cancers. Superficial X-rays from a Pantak Therapax unit SXT 150 model of HVL 4.90mm Al were used for the lead eye shield measurements and electrons from a Varian Clinac 2100C nominal energies 6MeV and 9MeV (Rp 3.00cm and 4.34cm respectively) were used for the tungsten eye shield measurements. For the photon measurements circular applicators of 3cm, 4cm and 5cm diameter were used and for the electrons standard 6x6cm and 10x 10cm applicators were used, with no custom inserts. A Scanditronix RFA-300 water phantom and Scanditronix RFAplus version 5.3 software applictronix RFAplus version 5.3 software application were used to collect and collate all data. The eye shields were the Radiation Products Design Inc. medium lead eye shield (item 934-014) and the MED-TEC tungsten eye shields MT-T-45 M and MT-T-45 S. It is demonstrated that electron fields have appreciably greater scatter into the area directly under the eye shields than the photon fields. Similarly at the region of dmax for the electron fields the relative dose is appreciably greater than the photon fields at similar depth. The relative merits for electron and photon treatments are discussed with respect to the investigations findings and reference to the literature. When comparing electrons and photons it is usually the definite range of electrons within tissue that recommends electron treatments. However, one should weigh this consideration against some of the salient features of a well-constructed superficial photon treatment, for example the effective blocking of kilovoltage photons by lead and the sharp edges of the kilovoltage photon fields. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

375

Eye movement inhibits the facilitation of perceptual filling-in.  

Science.gov (United States)

When a small figure is presented in human peripheral vision, it becomes invisible and invaded by surrounding texture, within a few seconds. This visual illusion is called perceptual filling-in. Time to filling-in (filling-in time) is varied by the properties of small figure, surround texture and some experimental conditions. In our preliminary study (Yokota, IEEE/IC-EMBS 2005), we found that incomplete fixation distributes filling-in time. Furthermore, that we can see nothing by restraining eye movement artificially is well known. Therefore, we can consider that filling-in time is influenced by eye movement. Although it has been recently reported that eye movement influences the filling-in occurrence (Martinez-Conde, Neuron 2006), the relation between eye movement and the filling-in time has rarely been reported. For this study, we measured the filling-in time for three subjects, for four surrounding textures, with simultaneous recording of eye movement. The results show that the filling-in time correlates to the standard deviation of the power of the eye distance from the fixation point. Furthermore, we found relatively strong correlation between the filling-in time and the power of high frequency component 50-200 (Hz) in the eye movement, though the correlation of the power of low frequency component 10-50 (Hz) is not so high. Thus we suppose that filling-in is inhibited by small involuntary eye movement. PMID:21096729

Yokota, Masae; Yokota, Yasunari

2010-01-01

376

An informatics system for exploring eye movements in reading  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Eye tracking techniques have been widely used in many research areas including cognitive science, psychology, human-computer interaction, marketing research, medical research etc. Many computer programs have emerged to help these researchers to design experiments, present visual stimuli and process the large quantity of numerical data produced by the eye tracker. However, most applications, especially commercial products, are designed for a particular tracking device and ten...

Tang, Siliang

2011-01-01

377

Investigation of a slope-point-based method for the design of aspheric surfaces in a catadioptric collimating optical system for a light-emitting diode source.  

Science.gov (United States)

The aim of this paper is to develop a straightforward rigorous and flexible computational method to determine the coordinate points on an aspheric surface. The computational method chosen is based on the basic slope-point form of a straight-line equation [slope-point method (SPM)]. The practical instrumental example chosen to illustrate this method is a rotationally symmetric catadioptric collimator for a light-emitting diode (LED) source. This optical system has both a refractive and a totally internally reflective aspheric surface. It is a particularly illuminating example because it requires careful computational attention to the smooth transition between the refracting inner zones and the reflective outer zones of the aperture. The chosen SPM computational method deals satisfactorily with the transition points at the junction between the refractive and total internal reflecting (TIR) zones of the collimator. As part of this study, the effect of the position of the start point of the SPM surface evolution for the TIR zones of the collimator emerges as being particularly important, and the details of this are discussed. Finally, an extension of the basic SPM-based method is used to generalize the development of the catadioptric collimator surfaces to illustrate this general algorithm for aspheric surface design for an extended LED light source. PMID:25322409

Chen, Rung-Sheng

2014-10-10

378

Incorporation of intraocular scattering in schematic eye models  

International Nuclear Information System (INIS)

Beckmann's theory of scattering from rough surfaces is applied to obtain, from the experimental veiling glare functions, a diffuser that when placed at the pupil plane would produce the same scattering halo as the ocular media. This equivalent diffuser is introduced in a schematic eye model, and its influence on the point-spread function and the modulation-transfer function of the eye is analyzed

379

Real-time and Offline Filters for Eye Tracking  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An eye tracker makes it possible to record the gaze point of a person looking at for example a computer monitor. Modern techniques are very flexible and allow the user to behave naturally without the need of cumbersome equipment such as special contact lenses or electrical probes. This is valuable in psychological research, marketing research and Human Computer Interaction. Eye trackers also give people who are severely paralyzed and unable to type and speak means to communicate using their e...

Olsson, Pontus

2007-01-01

380

Robust Eye and Pupil Detection Method for Gaze Tracking  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Robust and accurate pupil detection is a prerequisite for gaze detection. Hence, we propose a new eye/pupil detection method for gaze detection on a large display. The novelty of our research can be summarized by the following four points. First, in order to overcome the performance limitations of conventional methods of eye detection, such as adaptive boosting (Adaboost) and continuously adaptive mean shift (CAMShift) algorithms, we propose adaptive selection of the Adaboost and CAMShift met...

Su Yeong Gwon; Chul Woo Cho; Hyeon Chang Lee; Won Oh Lee; Kang Ryoung Park

2013-01-01

 
 
 
 
381

Baseline (laser) eye examination program.  

Science.gov (United States)

Eye injury is the primary hazard associated with laser use. A baseline laser eye examination program allows for pre-injury examination and preventive early diagnosis of eye problems (glaucoma). Using portable equipment and a simplified exam format, and staffed by corpsmen and eye care providers, a rapid and accurate large-scale program that is cost efficient can be instituted. A single location for ophthalmic information coupled with recent refraction data will enhance readiness for deployment. For service members and their providers, a new and well-run eye care program will foster a strong and positive bond with the medical department. PMID:8637648

Greenberg, S M; Olson, E

1996-03-01

382

Optoelectronic eye tracking system  

Science.gov (United States)

The eye movement monitor measures both vertical and horizontal eye movements by employing an optoelectronic noncontact technique with a high updates rate. The monitor is controlled by an IBM AT or compatible computer and basically consists of a sensor assembly and two cards, connected to the PC bus: an amplifier and synchronous detection unit and a 12 bit AD/DA converter. The sensor assembly is mounted to spectacle frames and connected with the computer by a flexible cable. All the measurement data are stored in the hard disk and can be represented as vertical and horizontal coordinates of the gaze at selected time moments. The monitor does not interfere with the subject's head movements nor does it obstruct significantly his view of vision. The pulsed bias and synchronous detection make the device insensitive to the background illumination artifacts.

Navikas, Saulius; Verkelis, Jonas

1997-02-01

383

Genetic analyses of the human eye colours using a novel objective method for eye colour classification.  

Science.gov (United States)

In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically identified and extracted from high resolution digital images. DIAT was made user friendly with a graphical user interface. The software counted the number of blue and brown pixels in the iris image and calculated a Pixel Index of the Eye (PIE-score) that described the eye colour quantitatively. The PIE-score ranged from -1 to 1 (brown to blue). The software eliminated the need for user based interpretation and qualitative eye colour categories. In 94% (570) of 605 analyzed eye images, the iris region was successfully extracted and a PIE-score was calculated. A very high correlation between the PIE-score and the human perception of eye colour was observed. The correlations between the PIE-scores and the six IrisPlex SNPs (HERC2 rs12913832, OCA2 rs1800407, SLC24A4 rs12896399, TYR rs1393350, SLC45A2 rs16891982 and IRF4 rs12203592) were analyzed in 570 individuals. Significant differences (prs12913832 G (PIE=0.99) and rs12913832 GA (PIE=-0.71) or A (PIE=-0.87) were observed. We adjusted for the effect of HERC2 rs12913832 and showed that the quantitative PIE-scores were significantly associated with SNPs with minor effects (OCA2 rs1800407, SLC24A4 rs12896399 and TYR rs1393350) on the eye colour. We evaluated the two published prediction models for eye colour (IrisPlex [1] and Snipper[2]) and compared the predictions with the PIE-scores. We found good concordance with the prediction from individuals typed as HERC2 rs12913832 G. However, both methods had difficulties in categorizing individuals typed as HERC2 rs12913832 GA because of the large variation in eye colour in HERC2 rs12913832 GA individuals. With the use of the DIAT software and the PIE-score, it will be possible to automatically compare the iris colour of large numbers of iris images obtained by different studies and to perform large meta-studies that may reveal loci with small effects on the eye colour. PMID:23948321

Andersen, Jeppe D; Johansen, Peter; Harder, Stine; Christoffersen, Susanne R; Delgado, Mikaela C; Henriksen, Sarah T; Nielsen, Mette M; Sørensen, Erik; Ullum, Henrik; Hansen, Thomas; Dahl, Anders L; Paulsen, Rasmus R; Børsting, Claus; Morling, Niels

2013-09-01

384

A novel device for head gesture measurement system in combination with eye-controlled human machine interface  

Science.gov (United States)

This study describes the design and combination of an eye-controlled and a head-controlled human-machine interface system. This system is a highly effective human-machine interface, detecting head movement by changing positions and numbers of light sources on the head. When the users utilize the head-mounted display to browse a computer screen, the system will catch the images of the user's eyes with CCD cameras, which can also measure the angle and position of the light sources. In the eye-tracking system, the program in the computer will locate each center point of the pupils in the images, and record the information on moving traces and pupil diameters. In the head gesture measurement system, the user wears a double-source eyeglass frame, so the system catches images of the user's head by using a CCD camera in front of the user. The computer program will locate the center point of the head, transferring it to the screen coordinates, and then the user can control the cursor by head motions. We combine the eye-controlled and head-controlled human-machine interface system for the virtual reality applications.

Lin, Chern-Sheng; Ho, Chien-Wa; Chang, Kai-Chieh; Hung, San-Shan; Shei, Hung-Jung; Yeh, Mau-Shiun

2006-06-01

385

Obesity and Eye Diseases  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The prevalence of obesity has reached epidemic proportions in many countries. While its impact on overall health is well documented, less is known about the ocular manifestations of obesity. Amongst different eye diseases, obesity has been linked with age-related cataract, glaucoma, age-related maculopathy, and diabetic retinopathy. Numerous population-based and prospective studies support an association between obesity and risk of age-related cataract. However, the nature and strength of the...

Cheung, Ning; Wong, Tien Y.

2007-01-01

386

Gray Eye Traffic Surveillance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Gray Eye Traffic Surveillance (GETS) is a system based on image processing technology and database processing for the purpose of Traffic Surveillance. This system is built specifically for India, where standard fonts and scripts for the number plates are rarely followed and corruption is a menace.This paper attempts to present a system to automate the entire process of traffic surveillance and curb corruption at the same time. A two way approach of developing a desktop and a web based mobile ...

Ayesha Butalia, Durgesh Maru

2011-01-01

387

Michelangelo's eye disease.  

Science.gov (United States)

Charged by the Pope Julius II for painting the Cappella Sistina in Rome (between 1508 and 1512), Michelangelo worked in an elevated scaffolding, in an anomalous position with dyes (including poisoning lead salts) and solvents (such as toxic turpentine) dripping on his face and continuously inhaling, in a dim environment illuminated only with oil lamps and candles, as he described himself and sketched in a sonet addressed to Giovanni da Pistoia. In 1510 he began suffering from eye disease: the main symptom was the necessity to elevate the document he was reading up to the level of his eyes. This defect disappeared few months after he finished painting his masterpiece. We hypothesize that the Michelangelo's eyes disease was a form of acquired and transitory nystagmus induced by the many hours he spent in up gaze, with a skew deviation, a form of ocular tilt reaction resulting from the impairment of spatial sensitivity (inversion illusion) due to the persistence of the artist's head in a horizontal position, looking upward. PMID:22425178

Gallenga, P E; Neri, Giampiero; D'Anastasio, Ruggero; Pettorrossi, Vito Enrico; Alfieri, Emilio; Capasso, Luigi

2012-06-01

388

The ?-ray energy and angular response of the EYE-Deye-lens dosemeter  

International Nuclear Information System (INIS)

Following the recent ICRP recommendation to decrease the limit of occupational exposure to the eye lens from 150 mSv to 20 mSv/year, a dedicated individual eye-lens dosemeter, EYE-D™, was developed at the IFJ PAN. This dosemeter uses MCP-N (LiF:Mg,Cu,P) thermoluminescent detectors covered with a polyamide capsule and was so far optimized to achieve a flat photon energy and angular response for X-ray exposures typical in interventional radiology. To verify the applicability of this eye-lens dosemeter in external ?-ray fields which arise, e.g. in nuclear medicine procedures, we measured and calculated its ?-ray energy and angular response. Measurements, applying ?-rays from Sr-90/Y-90 isotope, were performed at the Beta Secondary Standard type 2 (BSS 2) in CLOR. Calculations, using the PENELOPE Monte Carlo transport code which simulates coupled electron and photon transport in arbitrary materials, were performed for P-32, K-42 and Sr-90/Y-90 fields to simulate doses received by the eye lens within the human body. PENELOPE Monte Carlo transport code was also used to calculate doses received with EYE-D™ detectors. We found good agreement between the measured and calculated energy and angular responses which confirms the suitability of this dosemeter in assessing Hp(3) to estimate the eye lens. Obtained results and conclusions, however preliminary, conform with current ICRP recommendations when performing individual radiation protection dosimetry in external ?-ray fields occurring in nuclear industry and nuclear medicine activities. -- Highlights: •The applicability of EYE-Deye-lens dosemeter in external ?-ray fields have been investigated. •Measurements and calculations ?-ray energy and angular response of EYE-D™ have been performed. •A comparison of calculations results with experimental data is presented. •Obtained results confirmed the suitability of this dosemeter in assessing Hp(3) to estimate the eye lens

389

Can the Hazard Assessment and Critical Control Points (HACCP system be used to design process-based hygiene concepts?  

Directory of Open Access Journals (Sweden)

Full Text Available Recently, the HACCP (Hazard Analysis and Critical Control Points concept was proposed as possible way to implement process-based hygiene concepts in clinical practice, but the extent to which this food safety concept can be transferred into the health care setting is unclear. We therefore discuss possible ways for a translation of the principles of the HACCP for health care settings. While a direct implementation of food processing concepts into health care is not very likely to be feasible and will probably not readily yield the intended results, the underlying principles of process-orientation, in-process safety control and hazard analysis based counter measures are transferable to clinical settings. In model projects the proposed concepts should be implemented, monitored, and evaluated under real world conditions.

Hübner, N.-O.

2011-01-01

390

A rigorous analysis using optimal transport theory for a two-reflector design problem with a point source  

International Nuclear Information System (INIS)

We consider the following geometric optics problem: construct a system of two reflectors which transforms a spherical wavefront generated by a point source into a beam of parallel rays. This beam has a prescribed intensity distribution. We give a rigorous analysis of this problem. The reflectors we construct are (parts of) the boundaries of convex sets. We prove existence of solutions for a large class of input data and give a uniqueness result. To the author's knowledge, this is the first time that a rigorous mathematical analysis of this problem is given. The approach is based on optimal transportation theory. It yields a practical algorithm for finding the reflectors. Namely, the problem is equivalent to a constrained linear optimization problem

391

Design and implementation of a beam-waveguide mirror control system for vernier pointing of the DSS-13 antenna  

Science.gov (United States)

The design and implementation of an antenna beam-waveguide (BWG) mirror position control system at the DSS-13 34-m antenna is presented. While it has several potential applications, a positioner on the last flat-plate BWG mirror (M6) at DSS 13 is installed to demonstrate the conical scan (conscan) angle-tracking technique at the Ka-band (32-GHz) operating frequency. Radio frequency (RF) beam-scanning predictions for the M6 mirror, computed from a diffraction analysis, are presented. From these predictions, position control system requirements are then derived. The final mechanical positioner and servo system designs, as implemented at DSS 13, are illustrated with detailed design descriptions given in the appendices. Preliminary measurements of antenna Ka-band beam scan versus M6 mirror tilt made at DSS 13 in December 1993 are presented. After reduction, the initial measurements are shown to be in agreement with the RF predicts. Plans for preliminary conscan experimentation at DSS 13 are summarized.

Alvarez, L. S.; Moore, M.; Veruttipong, W.; Andres, E.

1994-01-01

392

Eye movement; Experimental and clinical study using cine mode MRI  

Energy Technology Data Exchange (ETDEWEB)

This is a special lecture at the 96th Annual Congress of the Japanese Ophthalmological Society in 1992, presenting studies on eye movement using magnetic resonance imaging (MRI). Using cine mode MRI technology, two methods for producing a series of photographs have been invented: (1) the moving eye method or dynamic method in which the subjects were asked to perform 256 or 512 vertical and horizontal eye movements in synchronization with a sound trigger; and (2) the fixed eye method or static method in which the subjects were asked to gaze at individual points in a 5 to 7 point sequence as indicated by the investigator. MRI data was generated and the resulting series of photographs were observed in cine mode on a televisin monitor. Displaying the MRI-generated photographs in cine mode enables direct observation of eye movement, optic nerve and extraocular muscles within the orbit. Although the moving eye method is more accurate in its portrayal of the actual eye movement, at least 256 eye movements are required for about 5 minutes, causing physical and mental load for the subjects. The fixed eye method was thus used to examine ophthalmoplegia, including abducens palsy, oculomotor palsy, fracture of the orbital wall, foreign bodies in the orbit, Duane's syndrome, endocrine myopathy, esotropia and exotropia. This allowed the investigation of anatomical changes, such as atrophy or hypertrophy, and the functional state caused by contraction and relaxation of the extraocular muscles. Transposition of the extraocular muscles for paralytic squint was reexamined and a new surgical procedure was developed for abducens palsy. The measurement of the length, thickness and weight of the extraocular muscles from the MRI-generated photographs allowed more accurate analysis. Three dimensional reconstructive method of MRI provided a valuable tool for evaluating the orbit. (N.K.) 67 refs.

Inatomi, Akihiro (Shiga University of Medical Science, Otsu (Japan)); Kaji, Kazutaka; Sasaki, Kenji (and others)

1992-12-01

393

ECEM (Eye Closure, Eye Movements): application to depersonalization disorder.  

Science.gov (United States)

Eye Closure, Eye Movements (ECEM) is a hypnotically-based approach to treatment that incorporates eye movements adapted from the Eye Movement Desensitization and Reprocessing (EMDR) protocol in conjunction with hypnosis for the treatment of depersonalization disorder. Depersonalization Disorder has been differentiated from post-traumatic stress disorders and has recently been conceptualized as a subtype of panic disorder (Baker et al., 2003; David, Phillips, Medford, & Sierra, 2004; Segui et. al., 2000). During ECEM, while remaining in a hypnotic state, clients self-generated six to seven trials of eye movements to reduce anticipatory anxiety associated with depersonalization disorder. Eye movements were also used to process triggers that elicited breath holding, often followed by episodes of depersonalization. Hypnotic suggestions were used to reverse core symptoms of depersonalization, subjectively described as "feeling unreal" (Simeon et al., 1997). PMID:19862896

Harriet, E Hollander

2009-10-01

394

Effect of differing PowerPoint slide design on multiple-choice test scores for assessment of knowledge and retention in a theriogenology course.  

Science.gov (United States)

Third-year veterinary students in a required theriogenology diagnostics course were allowed to self-select attendance at a lecture in either the evening or the next morning. One group was presented with PowerPoint slides in a traditional format (T group), and the other group was presented with PowerPoint slides in the assertion-evidence format (A-E group), which uses a single sentence and a highly relevant graphic on each slide to ensure attention is drawn to the most important points in the presentation. Students took a multiple-choice pre-test, attended lecture, and then completed a take-home assignment. All students then completed an online multiple-choice post-test and, one month later, a different online multiple-choice test to evaluate retention. Groups did not differ on pre-test, assignment, or post-test scores, and both groups showed significant gains from pre-test to post-test and from pre-test to retention test. However, the T group showed significant decline from post-test to retention test, while the A-E group did not. Short-term differences between slide designs were most likely unaffected due to required coursework immediately after lecture, but retention of material was superior with the assertion-evidence slide design. PMID:25000882

Root Kustritz, Margaret V

2014-01-01

395

Eye gaze tracking using correlation filters  

Science.gov (United States)

In this paper, we studied a method for eye gaze tracking that provide gaze estimation from a standard webcam with a zoom lens and reduce the setup and calibration requirements for new users. Specifically, we have developed a gaze estimation method based on the relative locations of points on the top of the eyelid and eye corners. Gaze estimation method in this paper is based on the distances between top point of the eyelid and eye corner detected by the correlation filters. Advanced correlation filters were found to provide facial landmark detections that are accurate enough to determine the subjects gaze direction up to angle of approximately 4-5 degrees although calibration errors often produce a larger overall shift in the estimates. This is approximately a circle of diameter 2 inches for a screen that is arm's length from the subject. At this accuracy it is possible to figure out what regions of text or images the subject is looking but it falls short of being able to determine which word the subject has looked at.

Karakaya, Mahmut; Bolme, David; Boehnen, Chris

2014-03-01

396

More Than Meets the Eye The Genetics of Eye Color  

Science.gov (United States)

The genetics of eye color are more complex than commonly believed. This interrupted case study uses the story of a blue-eyed couple with a brown-eyed child to explore the possible scenarios that could result in this outcome. The case emphasizes the link between Mendelian genetics and the underlying molecular basis of the phenotype. It is appropriate for upper-level undergraduate biology majors with a good understanding of eukaryotic gene regulation and Mendelian genetics.

Genereux, Annie P.

2011-01-01

397

Process of Designing Robust, Dependable, Safe and Secure Software for Medical Devices: Point of Care Testing Device as a Case Study  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a holistic methodology for the design of medical device software, which encompasses of a new way of eliciting requirements, system design process, security design guideline, cloud architecture design, combinatorial testing process and agile project management. The paper uses point of care diagnostics as a case study where the software and hardware must be robust, reliable to provide accurate diagnosis of diseases. As software and software intensive systems are becoming increasingly complex, the impact of failures can lead to significant property damage, or damage to the environment. Within the medical diagnostic device software domain such failures can result in misdiagnosis leading to clinical complications and in some cases death. Software faults can arise due to the interaction among the software, the hardware, third party software and the operating environment. Unanticipated environmental changes and latent coding errors lead to operation faults despite of the fact that usually a significant effort has been expended in the design, verification and validation of the software system. It is becoming increasingly more apparent that one needs to adopt different approaches, which will guarantee that a complex software system meets all safety, security, and reliability requirements, in addition to complying with standards such as IEC 62304. There are many initiatives taken to develop safety and security critical systems, at different development phases and in different contexts, ranging from infrastructure design to device design. Different approaches are implemented to design error free software for safety critical systems. By adopting the strategies and processes presented in this paper one can overcome the challenges in developing error free software for medical devices (or safety critical systems.

Sivanesan Tulasidas

2013-08-01

398

New eye phantom for ophthalmic surgery  

Science.gov (United States)

In this work, we designed and realized a new phantom able to mimic the principal mechanical, rheological, and physical cues of the human eye and that can be used as a common benchmark to validate new surgical procedures, innovative vitrectomes, and as a training system for surgeons. This phantom, in particular its synthetic humor vitreous, had the aim of reproducing diffusion properties of the natural eye and can be used as a system to evaluate the pharmacokinetics of drugs and optimization of their dose, limiting animal experiments. The eye phantom was built layer-by-layer starting from the sclera up to the retina, using low cost and easy to process polymers. The validation of the phantom was carried out by mechanical characterization of each layer, by diffusion test with commercial drugs into a purposely developed apparatus, and finally by a team of ophthalmic surgeons. Experiments demonstrated that polycaprolactone, polydimethylsiloxane, and gelatin, properly prepared, are the best materials to mimic the mechanical properties of sclera, choroid, and retina, respectively. A polyvinyl alcohol-gelatin polymeric system is the best for mimicking the viscosity of the human humor vitreous, even if the bevacizumab half-life is lower than in the human eye.

Fogli, Gessica; Orsi, Gianni; De Maria, Carmelo; Montemurro, Francesca; Palla, Michele; Rizzo, Stanislao; Vozzi, Giovanni

2014-06-01

399

Understanding the Structure of the Eye  

Science.gov (United States)

Students learn about the anatomical structure of the human eye and how humans see light, as well as some causes of color blindness. They conduct experiments as an example of research to gather information. During their investigations, they test other students' vision, gathering data and measurements about when objects appear blurry. These topics help students prepare to design solutions to an overarching engineering challenge question.

Research Experience for Teachers (RET) Program, Center of Advancement of Engineering Fibers and Films,

400

Point Lepreau  

International Nuclear Information System (INIS)

Point Lepreau, Atlantic Canada's first nuclear generating station, went critical July 25, 1982. The plant, the first 600-MW CANDU to go into operation, took 96 months to build in spite of the fact that its steam generator tubes had to be replaced because of denting problems. The reactor is the first in Canada to be cooled by sea water; strict environmental protection standards were followed during design and construction. A contract has been signed with a Massachusetss electrical utility and permission has been granted to export electricity to the United States. A second reactor may be built at the site to produce electricity for export. New Brunswick expects to save money by producing electricity from uranium rather than oil, and to benefit in other ways from the use of an advanced technology

 
 
 
 
401

Assessing and managing eye injuries  

Directory of Open Access Journals (Sweden)

Full Text Available njuries to the eye are common. Many are minor but, if not treated quickly and appropriately, can lead to sight-threatening complications. Other injuries are severe, and even with expert management sight can be lost. Prevention of blindness from eye injuries requires: * injury prevention (health promotion including advocacy * early presentation by the patient (health promotion and health worker training * accurate assessment (good primary eye care and first aid * prompt referral of serious injuries requiring specialist management.

Karin Lecuona

2005-10-01

402

The eye and the heart  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The vasculature of the eye and the heart share several common characteristics. The easily accessible vessels of the eye are therefore-to some extent-a window to the heart. There is interplay between cardiovascular functions and risk factors and the occurrence and progression of many eye diseases. In particular, arteriovenous nipping, narrowing of retinal arteries, and the dilatation of retinal veins are important signs of increased cardiovascular risk. The pressure in the dilated veins is oft...

Flammer, J.; Konieczka, K.; Bruno, R. M.; Virdis, A.; Flammer, A. J.; Taddei, S.

2013-01-01

403

Integrated modeling of steel refining, casting and rolling operations to obtain design set points for quality steel sheet production  

Science.gov (United States)

Non-metallic inclusions are defects present in steel which disrupt the homogeneity of structure and adversely affects the mechanical properties. To some extent silo approach based mathematical models have been successfully used to modify and control inclusions in steel making but very few attempts have been made to deal with these processes in integrated framework. With computational advancement and high promising potential of ICME (Integrated Computational Materials Engineering), physics based models can be integrated which will lead to overall increase of process understanding, control and eventually to better properties and performance of material. The objectives of the present work are: (a) using CFD based models understand the influence of various design and process parameters on inclusion removal during secondary steel making, (b) using FEM model study the effects of type and characteristics of inclusions during solid state forming operations, and finally (c) integrate these models in order to develop an integrated modeling framework. This integrated framework will determine the extent up to which inclusions can be tolerated in downstream processes without affecting the quality and properties of final steel sheet significantly and suggest modifications in upstream processes if inclusions are above acceptable limit.

Gupta, Akash; Kumar, Prabhash; Anapagaddi, Ravikiran; Reddy, Niranjan; Goyal, Sharad; Singh, A. K.; Padmanabhan, K. A.

2013-05-01

404

A free geometry model-independent neural eye-gaze tracking system  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Eye Gaze Tracking Systems (EGTSs estimate the Point Of Gaze (POG of a user. In diagnostic applications EGTSs are used to study oculomotor characteristics and abnormalities, whereas in interactive applications EGTSs are proposed as input devices for human computer interfaces (HCI, e.g. to move a cursor on the screen when mouse control is not possible, such as in the case of assistive devices for people suffering from locked-in syndrome. If the user’s head remains still and the cornea rotates around its fixed centre, the pupil follows the eye in the images captured from one or more cameras, whereas the outer corneal reflection generated by an IR light source, i.e. glint, can be assumed as a fixed reference point. According to the so-called pupil centre corneal reflection method (PCCR, the POG can be thus estimated from the pupil-glint vector. Methods A new model-independent EGTS based on the PCCR is proposed. The mapping function based on artificial neural networks allows to avoid any specific model assumption and approximation either for the user’s eye physiology or for the system initial setup admitting a free geometry positioning for the user and the system components. The robustness of the proposed EGTS is proven by assessing its accuracy when tested on real data coming from: i different healthy users; ii different geometric settings of the camera and the light sources; iii different protocols based on the observation of points on a calibration grid and halfway points of a test grid. Results The achieved accuracy is approximately 0.49°, 0.41°, and 0.62° for respectively the horizontal, vertical and radial error of the POG. Conclusions The results prove the validity of the proposed approach as the proposed system performs better than EGTSs designed for HCI which, even if equipped with superior hardware, show accuracy values in the range 0.6°-1°.

Gneo Massimo

2012-11-01

405

Ultraviolet radiation: the eye  

International Nuclear Information System (INIS)

Under most conditions, the eye is well adapted to protect itself against ultraviolet radiation encountered in the outdoor environment as a result of the exposure geometry of the sun. Only when snow is on the ground does one experience acute effects of UV sunlight exposure (i.e. snow blindness, or photokeratitis). With regard to artificial sources, there are many occasions where one views bright light sources such as tungsten-halogen lamps, arc lamps and welding arcs. Such viewing is normally only momentary because of the aversion response to bright light and due to discomfort glare. However, such an aversion does not take place for germicidal lamps and other UV lamps which do not contain a strong visible component in their spectrum. The adverse effects from viewing such sources has been studied for decades and during the last two decades guidelines for limiting exposure to protect the eye have been developed. The guidelines were fostered to a large extent by the growing use of lasers and the quickly recognized hazard posed by viewing laser sources. (author)

406

Eye Surgery Light  

Science.gov (United States)

During eye surgery, the surgeon uses an illuminating instrument called an opthalmoscope for close examination of the retina or the interior of the eye. Ordinarily, electric power for the head-mounted light is supplied through a cord from an overhead swivel arm or a floor pedestal. Within limits of cord length and swivel arm movement, the surgeon has considerable freedom of motion. But when more than one opthalmoscope is involved, tangling and interference of the power cords becomes a problem. St. Luke's Hospital, Cleveland, Ohio asked Lewis Research Center for assistance in finding a solution. Lewis responded with a battery-powered system that totally frees the surgeon of attached cords and swivels. Borrowing from space technology, Lewis used small, lightweight nickel-cadmium batteries that can deliver high intensity light for an hour and can be recharged overnight. The Opthalmoscope Powerpack consists of eight batteries in three containers affixed to a webbed belt, and a novel on-off switch equipped with a springloaded plexiglass "flapper." The belt pack is worn underneath the surgical gown and the flapper permits the doctor to activate the switch by elbow pressure. Lewis built five units and they have been in service at St. Luke's Hospital for a year. Used for routine examinations as well as for surgery, they have demonstrated excellent reliability.

1978-01-01

407

Are 3-D Movies Bad for Your Eyes?  

Medline Plus

Full Text Available ... Low Vision Myopia (Nearsightedness) Pink Eye (Conjunctivitis) Presbyopia (Aging Eye) Stye Uveitis/Iritis See all Diseases & Conditions > ... Tweet Eye Health Lifestyle Topics Preventing Eye Injuries Healthy Eyes During Pregnancy Computer Usage & Eye Strain Maintaining ...

408

Are 3-D Movies Bad for Your Eyes?  

Medline Plus

Full Text Available ... for Simple Eye Problems Medical Marijuana for Glaucoma Pregnancy Preventing Eye Injuries Smokers Sports Using Eye Makeup ... Lifestyle Topics Preventing Eye Injuries Healthy Eyes During Pregnancy Computer Usage & Eye Strain Maintaining Your Sight with ...

409

Enzyme molecular mechanism as a starting point to design new inhibitors: a theoretical study of O-GlcNAcase.  

Science.gov (United States)

O-Glycoprotein 2-acetamino-2-deoxy-?-D-glucopyranosidase (O-GlcNAcase) hydrolyzes O-linked 2-acetamido-2-deoxy-?-D-glucopyranoside (O-GlcNAc) residues from post-translationally modified serine/threonine residues of nucleocytoplasmic protein. The chemical process involves substrate-assisted catalysis, where two aspartate residues have been identified as the two key catalytic residues of O-GlcNAcase. In this report, the first step of the catalytic mechanism used by O-GlcNAcase involving substrate-assisted catalysis has been studied using a hybrid quantum mechanical/molecular mechanical (QM/MM) Molecular Dynamics (MD) calculations. The free energy profile shows that the formation of the oxazoline intermediate in the O-GlcNAcase catalytic reaction takes place by means of a stepwise mechanism. The first step would be a cyclization of the acetomide group, which seems to be dependent on the proton transfer from a conserved aspartate, Asp298 in Clostridium perfringens O-GlcNAcase. From this new intermediate, a proton is transferred from the azoline ring to another conserved aspartate (Asp297) thus forming the oxazoline ion and departure of the aglycone. In addition, averaged values of protein-substrate interaction energy along the reaction path shows that, in fact, the transition states present the highest binding affinities. A deeper analysis of the binding contribution of the individual residues shows that Asp297, Asp298, and Asp401 are basically responsible of the stabilization of these complexes. These results would explain why O-(2-acetamido-2deoxy-d-glucopyranosylidene)amino-N-phenycarbamate (PUGNAc), 1,2-dideoxy-2'-methyl-?-D-glucopyranoso-[2,1-d]-?2'-thiazoline (NAG-thiazoline), and GlcNAcstatin derivatives are potent inhibitors of this enzyme, resembling the two transition states of the O-GlcNAcase catalytic reaction path. These results may be useful to rational design compounds with more interesting inhibitory activity. PMID:21542586

Lameira, Jerônimo; Alves, Cláudio Nahum; Tuñón, Iñaki; Martí, Sergio; Moliner, Vicent

2011-05-26

410

A self-calibrating, camera-based eye tracker for the recording of rodent eye movements  

Directory of Open Access Journals (Sweden)

Full Text Available Much of neurophysiology and vision science relies on careful measurement of a human or animal subject’s gaze direction. Video-based eye trackers have emerged as an especially popular option for gaze tracking, because they are easy to use and are completely non-invasive. However, video eye trackers typically require a calibration procedure in which the subject must look at a series of points at known gaze angles. While it is possible to rely on innate orienting behaviors for calibration in some nonhuman species, other species, such as rodents, do not reliably saccade to visual targets, making this form of calibration impossible. To overcome this problem, we developed a fully-automated infrared video eye-tracking system that is able to quickly and accurately calibrate itself without requiring cooperation from the subject. This technique relies on the optical geometry of the cornea and uses computer controlled motorized stages to rapidly estimate the geometry of the eye relative to the camera. The accuracy and precision of our system was carefully measured using an artificial eye, and its capability to monitor the gaze of rodents was verified by tracking spontaneous saccades and evoked oculomotor reflexes in head-fixed rats (in both cases, we obtained measurements that are consistent with those found in the literature. Overall, given its fully-automated nature and its intrinsic robustness against operator errors, we believe that our eye-tracking system enhances the utility of existing approaches to gaze-tracking in rodents and represents a valid tool for rodent vision studies.

DavideZoccolan

2010-11-01

411

A bionic eye actuated by ionic polymer-metal composite (IPMC) artificial muscle  

Science.gov (United States)

This research was conducted with the aim of developing an energy-efficient, noiseless, movable bionic eye for use in bionic toys. This novel bionic eye is actuated by an ionic polymer-metal composite actuator. The overall size of the eye was 39 mm in length, 45 mm in width, and 45 mm in thickness. The experimental results revealed such a bionic eye design is feasible. This type of bionic eye is appropriate for use in toys and robots to increase their visual impact.

Yu, Min; Li, Yuxiu; He, Qingsong; Song, Linlin; Dai, Zhendong

2011-04-01

412

Eye vision system using programmable micro-optics and micro-electronics  

Science.gov (United States)

Proposed is a novel eye vision system that combines the use of advanced micro-optic and microelectronic technologies that includes programmable micro-optic devices, pico-projectors, Radio Frequency (RF) and optical wireless communication and control links, energy harvesting and storage devices and remote wireless energy transfer capabilities. This portable light weight system can measure eye refractive powers, optimize light conditions for the eye under test, conduct color-blindness tests, and implement eye strain relief and eye muscle exercises via time sequenced imaging. Described is the basic design of the proposed system and its first stage system experimental results for vision spherical lens refractive error correction.

Riza, Nabeel A.; Amin, M. Junaid; Riza, Mehdi N.

2014-02-01

413

New clinical research strategies in thoracic oncology: clinical trial design, adaptive, basket and umbrella trials, new end-points and new evaluations of response  

Directory of Open Access Journals (Sweden)

Full Text Available In the genomics era, our main goal should be to identify large and meaningful differences in small, molecularly selected groups of patients. Classical phase I, II and III models for drug development require large resources, limiting the number of experimental agents that can be tested and making the evaluation of targeted agents inefficient. There is an urgent need to streamline the development of new compounds, with the aim of identifying “trials designed to learn”, which could lead to subsequent “trials designed to conclude”. Basket trials are often viewed as parallel phase II trials within the same entity, designed on the basis of a common denominator, which can be a molecular alteration(s. Most basket trials are histology-independent and aberration-specific clinical trials. Umbrella trials are built on a centrally performed molecular portrait and molecularly selected cohorts with matched drugs, and can include patients’ randomisation and strategy validation. Beyond new designs, new end-points and new evaluation techniques are also warranted to finally achieve methodology and clinical improvements, in particular within immunotherapy trials.

Jessica Menis

2014-09-01

414

New clinical research strategies in thoracic oncology: clinical trial design, adaptive, basket and umbrella trials, new end-points and new evaluations of response.  

Science.gov (United States)

In the genomics era, our main goal should be to identify large and meaningful differences in small, molecularly selected groups of patients. Classical phase I, II and III models for drug development require large resources, limiting the number of experimental agents that can be tested and making the evaluation of targeted agents inefficient. There is an urgent need to streamline the development of new compounds, with the aim of identifying "trials designed to learn", which could lead to subsequent "trials designed to conclude". Basket trials are often viewed as parallel phase II trials within the same entity, designed on the basis of a common denominator, which can be a molecular alteration(s). Most basket trials are histology-independent and aberration-specific clinical trials. Umbrella trials are built on a centrally performed molecular portrait and molecularly selected cohorts with matched drugs, and can include patients' randomisation and strategy validation. Beyond new designs, new end-points and new evaluation techniques are also warranted to finally achieve methodology and clinical improvements, in particular within immunotherapy trials. PMID:25176973

Menis, Jessica; Hasan, Baktiar; Besse, Benjamin

2014-09-01

415

Building core capacities at the designated points of entry according to the International Health Regulations 2005: a review of the progress and prospects in Taiwan  

Directory of Open Access Journals (Sweden)

Full Text Available Background: As designated points of entry (PoEs play a critical role in preventing the transmission of international public health risks, huge efforts have been invested in Taiwan to improve the core capacities specified in the International Health Regulations 2005 (IHR 2005. This article reviews how Taiwan strengthened the core capacities at the Taoyuan International Airport (TIA and the Port of Kaohsiung (PoK by applying a new, practicable model. Design: An IHR PoE program was initiated for implementing the IHR core capacities at designated PoEs. The main methods of this program were 1 identifying the designated PoEs according to the pre-determined criteria, 2 identifying the competent authority for each health measure, 3 building a close collaborative relationship between stakeholders from the central and PoE level, 4 designing three stages of systematic assessment using the assessment tool published by the World Health Organization (WHO, and 5 undertaking action plans targeting the gaps identified by the assessments. Results: Results of the self-assessment, preliminary external assessment, and follow-up external assessment revealed a continuous progressive trend at the TIA (86, 91, and 100%, respectively, and at the PoK (77, 97, and 99.9%, respectively. The results of the follow-up external assessment indicated that both these designated PoEs already conformed to the IHR requirements. These achievements were highly associated with strong collaboration, continuous empowerment, efficient resource integration, and sustained commitments. Conclusions: Considering that many countries had requested for an extension on the deadline to fulfill the IHR 2005 core capacity requirements, Taiwan's experiences can be a source of learning for countries striving to fully implement these requirements. Further, in order to broaden the scope of public health protection into promoting global security, Taiwan will keep its commitments on multisectoral cooperation, human resource capacity building, and maintaining routine and emergency capacities.

Hsiao-Hsuan Chiu

2014-07-01

416

Building core capacities at the designated points of entry according to the International Health Regulations 2005: a review of the progress and prospects in Taiwan  

Science.gov (United States)

Background As designated points of entry (PoEs) play a critical role in preventing the transmission of international public health risks, huge efforts have been invested in Taiwan to improve the core capacities specified in the International Health Regulations 2005 (IHR 2005). This article reviews how Taiwan strengthened the core capacities at the Taoyuan International Airport (TIA) and the Port of Kaohsiung (PoK) by applying a new, practicable model. Design An IHR PoE program was initiated for implementing the IHR core capacities at designated PoEs. The main methods of this program were 1) identifying the designated PoEs according to the pre-determined criteria, 2) identifying the competent authority for each health measure, 3) building a close collaborative relationship between stakeholders from the central and PoE level, 4) designing three stages of systematic assessment using the assessment tool published by the World Health Organization (WHO), and 5) undertaking action plans targeting the gaps identified by the assessments. Results Results of the self-assessment, preliminary external assessment, and follow-up external assessment revealed a continuous progressive trend at the TIA (86, 91, and 100%, respectively), and at the PoK (77, 97, and 99.9%, respectively). The results of the follow-up external assessment indicated that both these designated PoEs already conformed to the IHR requirements. These achievements were highly associated with strong collaboration, continuous empowerment, efficient resource integration, and sustained commitments. Conclusions Considering that many countries had requested for an extension on the deadline to fulfill the IHR 2005 core capacity requirements, Taiwan's experiences can be a source of learning for countries striving to fully implement these requirements. Further, in order to broaden the scope of public health protection into promoting global security, Taiwan will keep its commitments on multisectoral cooperation, human resource capacity building, and maintaining routine and emergency capacities. PMID:25037903

Chiu, Hsiao-Hsuan; Hsieh, Jui-Wei; Wu, Yi-Chun; Chou, Jih-Haw; Chang, Feng-Yee

2014-01-01

417

Oxidative stress and its downstream signaling in aging eyes  

Science.gov (United States)

Background Oxidative stress (OS) and its biomarkers are the biochemical end point of the imbalance between reactive oxygen species (ROS) production and the ability of the antioxidant (AOX) biological systems to fight against oxidative injury. Objective We reviewed the role of OS and its downstream signaling in aging eyes. Methods A search of the literature and current knowledge on the physiological and pathological mechanisms of OS were revisited in relation to the eyes and the aging process. Most prevalent ocular diseases have been analyzed herein in relation to OS and nutraceutic supplements, such as dry-eye disorders, glaucoma, age-related macular degeneration, and diabetic retinopathy. Results Clinical, biochemical, and molecular data from anterior and posterior eye segment diseases point to OS as the common pathogenic mechanism in the majority of these ocular disorders, many of which are pathologies causing visual impairment, blindness, and subsequent loss of life quality. Studies with nutraceutic supplements in aging eye-related pathologies have also been reviewed. Conclusion OS, nutritional status, and nutraceutic supplements have to be considered within the standards of care of older ophthalmologic patients. OS biomarkers and surrogate end points may help in managing the aging population with ocular diseases. PMID:24748782

Pinazo-Duran, Maria Dolores; Gallego-Pinazo, Roberto; Garcia-Medina, Jose Javier; Zanon-Moreno, Vicente; Nucci, Carlo; Dolz-Marco, Rosa; Martinez-Castillo, Sebastian; Galbis-Estrada, Carmen; Marco-Ramirez, Carla; Lopez-Galvez, Maria Isabel; Galarreta, David J; Diaz-Llopis, Manuel

2014-01-01

418

Fly eye radar or micro-radar sensor technology  

Science.gov (United States)

To compensate for its eye's inability to point its eye at a target, the fly's eye consists of multiple angularly spaced sensors giving the fly the wide-area visual coverage it needs to detect and avoid the threats around him. Based on a similar concept a revolutionary new micro-radar sensor technology is proposed for detecting and tracking ground and/or airborne low profile low altitude targets in harsh urban environments. Distributed along a border or around a protected object (military facility and buildings, camp, stadium) small size, low power unattended radar sensors can be used for target detection and tracking, threat warning, pre-shot sniper protection and provides effective support for homeland security. In addition it can provide 3D recognition and targets classification due to its use of five orders more pulses than any scanning radar to each space point, by using few points of view, diversity signals and intelligent processing. The application of an array of directional antennas eliminates the need for a mechanical scanning antenna or phase processor. It radically decreases radar size and increases bearing accuracy several folds. The proposed micro-radar sensors can be easy connected to one or several operators by point-to-point invisible protected communication. The directional antennas have higher gain, can be multi-frequency and connected to a multi-functional network. Fly eye micro-radars are inexpensive, can be expendable and will reduce cost of defense.

Molchanov, Pavlo; Asmolova, Olga

2014-05-01

419

Awareness and perception regarding eye donation in students of a nursing college in Bangalore  

Directory of Open Access Journals (Sweden)

Full Text Available Context: Corneal diseases constitute a significant cause of visual impairment and blindness in the developing world. The number of corneal transplants done is far less than the actual requirement in India. This is largely due to the inadequate number of corneas collected. Well-informed nursing students could be expected to influence eye donation rates. Aims: To assess the awareness and perception of 188 first- and second-year nursing students towards eye donation in Bangalore. Settings and Design: Cross-sectional study design. Materials and Methods: A pretested, semi-structured questionnaire. Statistical Analysis Used: Data were analyzed using the Epi-Info software package, Version 6.04. Results: The majority (96.8% of students knew that eyes can be donated after death but only 38.2% knew that the ideal time of donation was within 6 hours of death. Most participants (85.1% were either willing or had already donated their eyes. Nobility in the act of eye donation was the main motivational force for eye donation according to 85.6% of students. Perceived reasons for not pledging eyes by the students were: the unacceptable idea of separating the eyes from the body (67.9%, lack of awareness (42.8%, objection by family members (28.5%, and unsuitability to donate because of health problem (10.7%. Conclusion: This study revealed that nursing students were well aware of eye donations and most of them were inclined to sign-up for eye donation. The perceived reasons for not donating eyes need to be considered while creating awareness about eye donation in the community. The nursing students could be actively involved as volunteers in eye donation campaigns and they can act as counsellors for eye donors. They can also contribute by participating in creating awareness and motivating people to become eye donors.

Gupta Anita

2009-01-01

420

Community Eye Health MSc dissertations  

Directory of Open Access Journals (Sweden)

Full Text Available All MSc students at the International Centre for Eye Health (ICEH carry out a dissertation project as part of the Community Eye Health MSc course. Most of the dissertations are excellent pieces of original and valuable research work, sometimes the first of their kind in their authors’ country or region.

Daksha Patel

2007-03-01

 
 
 
 
421

Dermatochalasis and dry eye.  

Science.gov (United States)

The medical records of 141 patients with dermatochalasis seen during the 32-month period of January 1989 through August 1991 were reviewed. Patients were classified on the basis of symptoms and mode of treatment and were examined for effectiveness of blepharoplasty in ameliorating these symptoms. Seventy-three patients (51.8%) had symptoms similar to those found in keratoconjunctivitis sicca, including mattering, burning, itching, redness, epiphora, foreign-body sensation, and photophobia. Of these 73 patients, 38 (52.1%) underwent upper eyelid blepharoplasty. Subjective improvement in symptoms was achieved in 33 of these patients (86.8%) postoperatively. Upper eyelid blepharoplasty may represent an effective component in the treatment of patients with dermatochalasis and dry-eye symptoms. PMID:8430731

Vold, S D; Carroll, R P; Nelson, J D

1993-02-15

422

Cat eye syndrome.  

Science.gov (United States)

A full-term female baby, a product of non-consanguineous marriage, was born at 37?weeks of gestation with a birth weight of 2.08?kg. Antenatal scan at 31?weeks revealed complex congenital heart disease with a hypoplastic right ventricle, pulmonary atresia and an intact septum. Immediately after birth, the infant was shifted to the nursery and was started on intravenous fluids and infusion prostaglandin E1 (Alprostidil). On examination, she had microcephaly, periorbital puffiness, a long philtrum, a broad nasal bridge and retrognathia, up slanting palpebral fissures, widely spaced nipples, a sacral dimple and right upper limb postaxial polydactyly. Postnatal echocardiography confirmed a large ostium secundum atrial septal defect with left to right shunt, right ventricle hypoplasia, pulmonary atresia with an intact septum and a large vertical patent ductus arteriosus. Ophthalmological examination showed a bilateral chorioretinal coloboma sparing disc and fovea. Karyotyping showed an extra small marker chromosome suggestive of the Cat eye syndrome. PMID:24842361

Sharma, Deepak; Murki, Srinivas; Pratap, Tejo; Vasikarla, Madhavi

2014-01-01

423

Gray Eye Traffic Surveillance  

Directory of Open Access Journals (Sweden)

Full Text Available Gray Eye Traffic Surveillance (GETS is a system based on image processing technology and database processing for the purpose of Traffic Surveillance. This system is built specifically for India, where standard fonts and scripts for the number plates are rarely followed and corruption is a menace.This paper attempts to present a system to automate the entire process of traffic surveillance and curb corruption at the same time. A two way approach of developing a desktop and a web based mobile application is proposed. The desktop based application uses image processing technology to recognize the license number from image of vehicles captured by surveillance cameras and maintain a track log. The web based mobile application can be used by authorized traffic police to file complaints. The general public can log into this application to view their log and file complaints in case of any discrepancies. Different database schemas are used for various purpose like authentication, crime details, tracking system.

Ayesha Butalia #1, Durgesh Maru*2, Kuldeep Baheti*3, Avais Mohammad*4, Ankit Bagdiya*5

2011-06-01

424

A robust eye position tracker based on invariant local features, eye motion, and infrared-eye responses  

Science.gov (United States)

Despite the effort made in the eye tracking community, the eye position tracking problem remains unsolved completely, due to the large variations in the eye appearance. This paper describes a multi-modal eye position tracker in dark/bright pupil image sequences. The tracking algorithm consists of detecting meaningful particles that correspond to IR-Pupil responses and eye motion, altering of particles through appearance models in the local invariant descriptor space, and matching of eye neighbors. Experimental validations have shown satisfactory performance in term of precision of eye position estimation, and robustness to 2D head rotations, translations, closed eye states, and reasonable out-of-plane rotations.

Hammoud, Riad I.

2005-05-01

425

Eye tracking and gating system for proton therapy of orbital tumors  

International Nuclear Information System (INIS)

Purpose: A new motion-based gated proton therapy for the treatment of orbital tumors using real-time eye-tracking system was designed and evaluated. Methods: We developed our system by image-pattern matching, using a normalized cross-correlation technique with LabVIEW 8.6 and Vision Assistant 8.6 (National Instruments, Austin, TX). To measure the pixel spacing of an image consistently, four different calibration modes such as the point-detection, the edge-detection, the line-measurement, and the manual measurement mode were suggested and used. After these methods were applied to proton therapy, gating was performed, and radiation dose distributions were evaluated. Results: Moving phantom verification measurements resulted in errors of less than 0.1 mm for given ranges of translation. Dosimetric evaluation of the beam-gating system versus nongated treatment delivery with a moving phantom shows that while there was only 0.83 mm growth in lateral penumbra for gated radiotherapy, there was 4.95 mm growth in lateral penumbra in case of nongated exposure. The analysis from clinical results suggests that the average of eye movements depends distinctively on each patient by showing 0.44 mm, 0.45 mm, and 0.86 mm for three patients, respectively. Conclusions: The developed automatic eye-tracking based beam-gating system enabled us to perform high-precision proton radiotherapy of orbital tumors.

426

Eye tracking and gating system for proton therapy of orbital tumors  

Energy Technology Data Exchange (ETDEWEB)

Purpose: A new motion-based gated proton therapy for the treatment of orbital tumors using real-time eye-tracking system was designed and evaluated. Methods: We developed our system by image-pattern matching, using a normalized cross-correlation technique with LabVIEW 8.6 and Vision Assistant 8.6 (National Instruments, Austin, TX). To measure the pixel spacing of an image consistently, four different calibration modes such as the point-detection, the edge-detection, the line-measurement, and the manual measurement mode were suggested and used. After these methods were applied to proton therapy, gating was performed, and radiation dose distributions were evaluated. Results: Moving phantom verification measurements resulted in errors of less than 0.1 mm for given ranges of translation. Dosimetric evaluation of the beam-gating system versus nongated treatment delivery with a moving phantom shows that while there was only 0.83 mm growth in lateral penumbra for gated radiotherapy, there was 4.95 mm growth in lateral penumbra in case of nongated exposure. The analysis from clinical results suggests that the average of eye movements depends distinctively on each patient by showing 0.44 mm, 0.45 mm, and 0.86 mm for three patients, respectively. Conclusions: The developed automatic eye-tracking based beam-gating system enabled us to perform high-precision proton radiotherapy of orbital tumors.

Shin, Dongho; Yoo, Seung Hoon; Moon, Sung Ho; Yoon, Myonggeun; Lee, Se Byeong; Park, Sung Yong [Proton Therapy Center, National Cancer Center, Goyang, Gyeonggi 410-769 (Korea, Republic of); Department of Radiation Oncology, CHA Bundang Medical Center, CHA University, Seongnam, Gyeonggi 463-712 (Korea, Republic of); Proton Therapy Center, National Cancer Center, Goyang, Gyeonggi 410-769 (Korea, Republic of); Department of Radiological Science, Korea University, Seoul 136-703 (Korea, Republic of); Proton Therapy Center, National Cancer Center, Goyang, Gyeonggi 410-769 (Korea, Republic of); Proton Therapy Center, McLaren Cancer Institute, Flint, Michigan 48532 (United States)

2012-07-15

427

Dry Eyes and Glaucoma: Double Trouble  

Science.gov (United States)

Dry Eyes and Glaucoma: Double Trouble email Send this article to a friend by filling out the fields below: ... disease bothers the patient more. What Causes Dry Eye Syndrome? Dry eye can be caused by many ...

428

Genetics Home Reference: Fish-eye disease  

Science.gov (United States)

... Recent literature OMIM Genetic disorder catalog Conditions > Fish-eye disease On this page: Description Genetic changes Inheritance Diagnosis ... Glossary definitions Reviewed August 2013 What is fish-eye disease? Fish-eye disease, also called partial LCAT deficiency, ...

429

Prevent Diabetes Problems: Keep Your Eyes Healthy  

Science.gov (United States)

... Series : Prevent diabetes problems: Keep your eyes healthy Prevent diabetes problems: Keep your eyes healthy On this ... t smoke. [ Top ] What can I do to prevent diabetes eye problems? You can do a lot ...

430

Diretrizes para seleção de projetistas e avaliação da prestação do serviço de projeto de edificações na visão do contratante / Guidelines for designers selection and evaluation of the design service from the building developer point of view  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A avaliação da prestação do serviço de projeto de edificações pode fomentar a relação entre os contratados (projetistas) e os contratantes (incorporador-construtor). Os resultados advindos da avaliação possibilitam a observação das dificuldades porventura ocorridas durante a prestação do serviço, a [...] análise do desempenho dos contratados, a retroalimentação de informações aos envolvidos, o planejamento de ações de melhorias e a seleção de projetistas em empreendimentos futuros. O objetivo deste trabalho é propor diretrizes para a seleção de projetistas e para a avaliação da PSP, sob a ótica do cliente contratante. Para esse fim, foram realizados estudos de caso em quatro empresas incorporadoras e construtoras e duas empresas de projeto da cidade de São Paulo. Os resultados mostram que as empresas incorporadoras e construtoras possuem suas práticas de seleção e avaliação de projetistas e que as empresas de projeto detêm práticas para avaliação da satisfação do cliente contratante. Ambos os tipos de avaliação mencionados - avaliação dos profissionais de projeto e da satisfação do cliente contratante - apresentam o mesmo objetivo: avaliar a prestação do serviço de projeto. A observação dessas práticas, somada à revisão bibliográfica realizada, contribuíram para a elaboração das diretrizes para a seleção de projetistas e para a avaliação da prestação do serviço de projeto. Abstract in english The evaluation of the building design service can improve the relationship between professionals (designers) and clients (real estate developers or construction companies). The evaluation results allow the observation of the difficulties that may have occurred during service provision, the assessmen [...] t of designers performance, provide feedback for the stakeholders, planning improvement actions, and the selection of designers for future projects. The aim of this study is to propose a set of guidelines for designer selection and design service evaluation from the building developer point of view. Case studies were carried out in four real estate developing companies and two design firms from the city of São Paulo. The results show that the builders and property developers have practices for designer selection and evaluation and that the design companies have practices for evaluating the satisfaction of their clients. Both types of evaluation - designer evaluation and evaluation of the contractor client satisfaction - have similar goals: to evaluate the design service. The observation of those practices and the literature review contributed to the elaboration of guidelines for designer selection and for the evaluation of the design service.

Nathália de, Paula; Celso Carlos, Novaes.

2010-12-01

431

Diretrizes para seleção de projetistas e avaliação da prestação do serviço de projeto de edificações na visão do contratante / Guidelines for designers selection and evaluation of the design service from the building developer point of view  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A avaliação da prestação do serviço de projeto de edificações pode fomentar a relação entre os contratados (projetistas) e os contratantes (incorporador-construtor). Os resultados advindos da avaliação possibilitam a observação das dificuldades porventura ocorridas durante a prestação do serviço, a [...] análise do desempenho dos contratados, a retroalimentação de informações aos envolvidos, o planejamento de ações de melhorias e a seleção de projetistas em empreendimentos futuros. O objetivo deste trabalho é propor diretrizes para a seleção de projetistas e para a avaliação da PSP, sob a ótica do cliente contratante. Para esse fim, foram realizados estudos de caso em quatro empresas incorporadoras e construtoras e duas empresas de projeto da cidade de São Paulo. Os resultados mostram que as empresas incorporadoras e construtoras possuem suas práticas de seleção e avaliação de projetistas e que as empresas de projeto detêm práticas para avaliação da satisfação do cliente contratante. Ambos os tipos de avaliação mencionados - avaliação dos profissionais de projeto e da satisfação do cliente contratante - apresentam o mesmo objetivo: avaliar a prestação do serviço de projeto. A observação dessas práticas, somada à revisão bibliográfica realizada, contribuíram para a elaboração das diretrizes para a seleção de projetistas e para a avaliação da prestação do serviço de projeto. Abstract in english The evaluation of the building design service can improve the relationship between professionals (designers) and clients (real estate developers or construction companies). The evaluation results allow the observation of the difficulties that may have occurred during service provision, the assessmen [...] t of designers performance, provide feedback for the stakeholders, planning improvement actions, and the selection of designers for future projects. The aim of this study is to propose a set of guidelines for designer selection and design service evaluation from the building developer point of view. Case studies were carried out in four real estate developing companies and two design firms from the city of São Paulo. The results show that the builders and property developers have practices for designer selection and evaluation and that the design companies have practices for evaluating the satisfaction of their clients. Both types of evaluation - designer evaluation and evaluation of the contractor client satisfaction - have similar goals: to evaluate the design service. The observation of those practices and the literature review contributed to the elaboration of guidelines for designer selection and for the evaluation of the design service.

Nathália de, Paula; Celso Carlos, Novaes.

432

Eyes on the LHC  

CERN Multimedia

"Particle physicists don't know for sure what explorations at the Large Hadron Collider will bring. But they do know that many mysteries in their field point toward solutions at the LHC's impressive TeV energy scale."

Gianotti, Fabiola

2007-01-01

433

Method for eye movements study  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Quantitative analysis of eye movements in Digital Domain, has permitted to increase the amount of physiological information extracted form oculographic signals. In the Neuroscience field, it allows to deepen on pathophysiological mechanisms underlying oculomotor dysfunctions. Objectives: The main goal of this work is to obtain quantitative methods able to reduce subjective components introduced by researchers during visual description or qualifications of neural signals, also reducing the experience required to successfully identify normal or abnormal electrophysiological patterns. Methods: Smooth pursuit eye movements were evaluated in 27 normal subjects by applying quantitative analysis methods in both time and frequency domains. A set of variables was determined which acted as quantitative descriptors of oculomotor response during task performance. Results: The results clearly shown that quantitative variables could be of great value in order to increase the sensitivity of eye movements analysis, also increasing the power of eye movements exploration to assess the neurophysiological basis underlying eye movements execution in either motor and cognitive contexts. The amount of information extracted from eye movement?s signals through this method exceeds the 80% of the total information available. Conclusions: Further studies must be conducted to evaluate how these variables behave in such disorders of central nervous system where eye movement?s dysfunctions appear.

Parra Mario Alfredo

2004-05-01

434

Mirror tilt immunity interferometry with a cat's eye retroreflector.  

Science.gov (United States)

This paper describes the behavior of a cat's eye retroreflector, which is incorporated in a novel way in a double-pass homodyne polarization interferometer. The amount of mirror tilt immunity a cat's eye provides is calculated within the paraxial approximation using 4×4 ABCD matrices. It is found that there is a position of the target mirror in which the tilt immunity is at a maximum. A real cat's eye, which is affected by aberrations, is optimized and examined using Zemax software for optical design. The maximum amount of mirror tilt immunity is numerically calculated and written in terms of defocus and spherical aberration. Finally, for the purposes of comparison, the amplitude of the Lissajous pattern as the target mirror tilts is calculated for both an interferometer with an integrated cat's eye and an interferometer with a cube corner. PMID:21364721

Peña-Arellano, Fabián E; Speake, Clive C

2011-03-01

435

Recent developments on dry eye disease treatment compounds.  

Science.gov (United States)

Dry eye syndrome is a common tears and ocular surface multifactorial disease, described by changes in the ocular surface epithelia related to reduced tears quantity and ocular surface sensitivity, leading to inflammatory reaction. Managing the eye inflammation proved helpful to patients with dry eye disease and current treatment is based on the use of topically applied artificial tear products/lubricants, tear retention management, stimulation of tear secretion and using anti-inflammatory drugs. In this article we revise the corresponding literature and patents assembling the new treatment approaches of novel and future pharmaceutical compounds destined for the dry eye disease treatment. The most frequent categories of compounds presented are secretagogues and anti-inflammatory drugs. These compounds are the research outcome of novel therapeutic strategies designed to reduce key inflammatory pathways and restore healthy tear film. PMID:24526854

Colligris, Basilio; Alkozi, Hanan Awad; Pintor, Jesus

2014-01-01

436

Case study: improving the management of eye care programmes  

Directory of Open Access Journals (Sweden)

Full Text Available Nigeria is a federation of 36 administrative States, which each have a mandate to deliver health care to their population. Sightsavers International has been supporting four State ministries of health (Cross River, Kaduna, Kwara, and Sokoto in implementing programmes designed to provide comprehensive eye care services.Previously, eye care had been limited to services in big hospitals in the largest cities, which were inaccessible to the general population.These new eye care programmes have been very successful. The Kwara eye care programme (KWECP, for example, has increased the cataract surgical rate from 196 cataract operations per million per year in 2003 to 932 in 2007.This article describes what we have learnt from our experience in managing these programmes and hopefully will provide you with suggestions to improve management.

Kolawole Olumide Ogundimu

2008-12-01

437

Design and fabrication of a miniaturization micro volume auto titrator coupled with electrochemical end-point detector for the determination of acidity of some fruit juice  

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Full Text Available A miniaturization micro volume auto titrator coupled with electrochemical end-point detector was designed and fabricated for the determination of acidity of some Thai citrus fruit juices collected in the northern area of Thailand. The method was based on on-line potentiometric titration of the acid contents with sodium hydroxide. Conditions such as volume of fruit juice sample, volume and concentration of potassium chloride used as supporting electrolyte and flow rate of titrant were optimized by using univariate optimization. A sample throughput of 83 samples h-1 at 0.28 mL/min was achieved with satisfactory results. The results obtained by the proposed method agreed with those obtained by using the standard classical titration method.

Prinya Masawat

2008-06-01

438

Radiation injuries of the eye and prophylactic measures  

International Nuclear Information System (INIS)

Radiation injuries of the eye, particularly the cataract, caused by different kinds of radiation such as ionizing radiations, laser beams, infrared radiation, and microwaves as well as the mechanisms of their origin are pointed out and connected problems of radiation protection are discussed

439

Managing your eye unit's supplies  

Directory of Open Access Journals (Sweden)

Full Text Available In order to deliver eye care, many resources have to be in place at the right time: your patients, your staff, your facilities, your equipment, and your supplies. In this article, we focus on how you can manage your supplies to ensure that your eye service runs smoothly. These supplies, or consumables, include every little thing needed in the course of your daily work: IOLs, medicines, gloves, forms used for patient care, housekeeping supplies, and equipment spares. If any of these items become unavailable, your eye centre will be unable to provide the same high quality of services, and you may even have to turn patients away.

RD Thulsiraj

2011-12-01

440

Odyssey of the Eyes: Advanced  

Science.gov (United States)

This activity helps students understand the connections between remote-sensing technology, computer imagery and land cover assessment, and models how a satellite sensor communicates information to a computer. Digital information from a map created through activities found in Odyssey of the Eyes: Beginner and Odyssey of the Eyes: Intermediate is reproduced in this activity and shared with others to process so they can see and identify the image. Odyssey of the Eyes: Beginner, Intermediate and Advanced are learning activities associated with the Land Cover/ Biology chapter of the GLOBE Teachers Guide.

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