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1

Atmospheric compensation of thermal infrared hyperspectral imagery with the emissive empirical line method and the in-scene atmospheric compensation algorithms: a comparison  

Microsoft Academic Search

The in-scene atmospheric compensation (ISAC) algorithm of Young et al. (2002) [14] (and as implemented in the ENVI® software system [16] as 'Thermal Atm Correction') is commonly applied to thermal infrared multi- and hyperspectral imagery (MSI and HSI, respectively). ISAC estimates atmospheric transmissivity and upwelling radiance using only the scene data. The ISAC-derived transmissivity and upwelling radiance are compared to

Robert J. Distasio Jr.; Ronald G. Resmini

2010-01-01

2

Atmospheric compensation of thermal infrared hyperspectral imagery with the emissive empirical line method and the in-scene atmospheric compensation algorithms: a comparison  

NASA Astrophysics Data System (ADS)

The in-scene atmospheric compensation (ISAC) algorithm of Young et al. (2002) [14] (and as implemented in the ENVI® software system [16] as 'Thermal Atm Correction') is commonly applied to thermal infrared multi- and hyperspectral imagery (MSI and HSI, respectively). ISAC estimates atmospheric transmissivity and upwelling radiance using only the scene data. The ISAC-derived transmissivity and upwelling radiance are compared to those derived from the emissive empirical line method (EELM), another in-scene atmospheric compensation algorithm for thermal infrared MSI and HSI data. EELM is based on the presence of calibration targets (e.g., panels, water pools) captured in the spectral image data for which the emissivity and temperature are well known at the moment of MSI/HSI data acquisition. EELM is similar in concept to the empirical line method (ELM) algorithm commonly applied to visible/near-infrared to shortwave infrared (VNIR/SWIR) spectral imagery and is implemented as a custom ENVI® plugin application. Both ISAC and EELM are in-scene methods and do not require radiative transfer modeling. ISAC and EELM have been applied to airborne longwave infrared (LWIR; ~7.5 ?m to ~13.5 ?m) HSI data. Captured in the imagery are calibration panels and/or water pools maintained at different temperatures facilitating the application of EELM. Overall, the atmospheric compensation parameters derived from the two methods are in close agreement: the EELM-derived ground-leaving radiance spectra generally contain fewer residual atmospheric spectral features, although ISAC sometimes produces smoother ground-leaving radiance spectra. Nonetheless, the agreement is viewed as validation of ISAC. ISAC is an effective atmospheric compensation algorithm that is readily available to the remote sensing community in the ENVI® software system. Thus studies such as the present testing and comparing ISAC to other methods are important. The ISAC and EELM algorithms are discussed as are the airborne LWIR and simulated HSI data to which they are applied. Also presented are analyses and comparisons of the retrieved transmissivity and upwelling radiance terms.

Distasio, Robert J., Jr.; Resmini, Ronald G.

2010-04-01

3

Implementation and validation of atmospheric compensation algorithms for Multispectral Thermal Imager (MTI) pipeline processing  

NASA Astrophysics Data System (ADS)

The Multispectral Thermal Imager (MTI) is a satellite system developed by the DoE. It has 10 spectral bands in the reflectance domain and 5 in the thermal IR. It is pointable and, at nadir, provides 5m IFOV in four visible and short near IR bands and 20m IFOV at longer wavelengths. Several of the bands in the reflectance domain were designed to enable quantitative compensation for aerosol effects and water vapor (daytime). These include 3 bands in and adjacent to the 940nm water vapor feature, a band at 1380nm for cirrus cloud detection and a SWIR band with small atmospheric effects. The concepts and development of these techniques have been described in detail at previous SPIE conferences and in journals. This paper describes the adaptation of these algorithms to the MTI automated processing pipeline (standardized level 2 products) for retrieval of aerosol optical depth (and subsequent compensation of reflectance bands for calibration to reflectance) and the atmospheric water vapor content (thermal IR compensation). Input data sources and flow are described. Validation results are presented. Pre-launch validation was performed using images from the NASA AVIRIS hyperspectral imaging sensor flown in the stratosphere on NASA ER-2 aircraft compared to ground based sun photometer and radiosonde measurements from different sources. These data sets span a range of environmental conditions.

Balick, Lee K.; Hirsch, Karen L.; McLachlan, Peter M.; Borel, Christoph C.; Clodius, William B.; Villanueve, Pierre V.

2000-11-01

4

Exploiting MODTRAN radiation transport for atmospheric correction: The FLAASH algorithm  

Microsoft Academic Search

Terrain categorization and target detection algorithms applied to hyperspectral imagery (HSI) typically operate on the measured reflectance (of sun and sky illumination) by an object or scene. Since the reflectance is a non-dimensional ratio, the reflectance by an object is nominally not affected by variations in lighting conditions. Atmospheric correction (referred to as atmospheric compensation, characterization, etc.) algorithms (ACAs) are

A. Berk; S. M. Adler-Golden; A. J. Ratkowski; G. W. Feldeb; G. P. Andersonb; M. L. Hoke; T. Cooley; J. H. Chetwynd; J. A. Gardner; M. W. Matthew; L. S. Bernstein; P. K. Acharya; D. Miller; P. Lewis

2002-01-01

5

Atmospheric dispersion compensation for extremely large telescopes.  

PubMed

Achieving diffraction limited imaging with future ground-based optical telescopes will require adaptive optics for correction of atmospheric turbulence and also efficient techniques for atmospheric dispersion compensation. We study the benefit of using a linear atmospheric dispersion corrector (ADC) coupled with a deformable mirror on a 42-m Extremely Large Telescope (ELT) operating in the VIRJ spectral bands. The ADC design consists of two identical thin wedges made of F5 glass. The amount of dispersion introduced by the ADC is adjusted by translating one of the wedges along the optical axis so that it always cancels atmospheric dispersion as it varies with telescope elevation. We show that the ADC working in conjunction with a deformable mirror provides diffraction-limited image quality over a 1-arcmin field. PMID:19532385

Goncharov, Alexander V; Devaney, Nicholas; Dainty, Christopher

2007-02-19

6

Understanding radiative transfer in the midwave infrared: a precursor to full-spectrum atmospheric compensation  

NASA Astrophysics Data System (ADS)

The compensation for atmospheric effects in the VNIR/SWIR has reached a mature stage of development with many algorithms available for application (ATREM, FLAASH, ACORN, etc.). Compensation of LWIR data is the focus of a number of promising algorithms. A gap in development exists in the MWIR where little or no atmospheric compensation work has been done yet an increased interest in MWIR applications is emerging. To obtain atmospheric compensation over the full spectrum (visible through LWIR), a better understanding of the radiative effects in the MWIR is needed. The MWIR is characterized by a unique combination of reduced solar irradiance and low thermal emission (for typical emitting surfaces), both providing relatively equal contributions to the daytime MWIR radiance. In the MWIR and LWIR, the compensation problem can be viewed as two interdependent processes: compensation for the effects of the atmosphere and the uncoupling of the surface temperature and emissivity. The former requires calculations of the atmospheric transmittance due to gases, aerosols, and thin clouds and the path radiance directed towards the sensor (both solar scattered and thermal emissions in the MWIR). A framework for a combined MWIR/LWIR compensation approach is presented where both scattering and absorption by atmospheric particles and gases are considered.

Griffin, Michael K.; Burke, Hsiao-hua K.; Kerekes, John P.

2004-08-01

7

Aeroballistic analyses for the Atmospheric Compensation Experiment  

SciTech Connect

The Atmospheric Compensation Experiment (ACE) involved illuminating a sounding rocket payload with a low power laser from the Air Force Maui Optical Site (AMOS), Mt. Haleakala, HI. This experiment, sponsored by DARPA and SDIO, included four launches of Terrier Malemute II rocket vehicles from the Kauai Test Facility during the period July through Dec., 1985. The purpose of ACE was to demonstrate an adaptive optics technology that allowed the efficient transfer of power from the laser to the space target. This paper discusses the rationale used in selecting the launch site and the requirements for the carrier rocket system. Each payload carried a light detector array along its longitudinal axis, and it was necessary that this array be oriented perpendicular to the line of sight from AMOS to the payload. The design requirements for the payload attitude control system to satisfy this requirement are presented. Flight test results from the four tests showing flight performance and payload pointing data are included.

Millard, W.A.

1986-01-01

8

A spatially adaptive fast atmospheric correction algorithm  

Microsoft Academic Search

An atmospheric correction algorithm for high spatial resolution satellite sensors like Landsat Thematic Mapper (TM) has been developed. The algorithm works with a catalogue of atmospheric correction functions stored in look-up tables. The catalogue consists of a broad range of atmospheric conditions (different altitude profiles of pressure, air temperature, and humidity; several aerosol types; ground elevations from 0-1?km above sea

R. Richter

1996-01-01

9

Attenuation compensation for cardiac single-photon emission computed tomographic imaging: Part 2. Attenuation compensation algorithms  

Microsoft Academic Search

Attenuation is believed to be one of the major causes of false-positive cardiac single-photon emission computed tomographic\\u000a perfusion images. This article provides an introduction to the approaches used to correct for nonuniform attenuation once\\u000a a patient-specific attenuation map is available. Comparison is made of specific attenuation-correction algorithms from each\\u000a of three major categories of compensation methods that are or will

Michael A. King; Benjamin M. W. Tsui; Tin-Su Pan; Stephen J. Glick; Edward J. Soares

1996-01-01

10

Weighted depth compensation algorithm for fluorescence molecular tomography reconstruction.  

PubMed

In fluorescence molecular tomography (FMT), diffuse-light measurements are obtained from a series of source-detector pairs placed on the boundary of the medium. The sensitivity of measurements deteriorates quickly with increased distance from the sources and detectors and therefore yields poor depth quantitative recovery. A depth compensation algorithm is presented in this paper to reconstruct fluorescent inclusions in deep tissues. Two weight matrixes are employed to level off sensitivity differences and enhance prominent elements of the solution. Results of numerical and phantom experiments demonstrate that both relative quantitation and spatial resolution of FMT are improved for inclusions at different depths. PMID:23262629

Liu, Fei; Li, Mingze; Zhang, Bin; Luo, Jianwen; Bai, Jing

2012-12-20

11

A new chromatic dispersion compensation method based on genetic algorithm  

NASA Astrophysics Data System (ADS)

In the 40Gbps high-speed optical fiber communication system, chromatic dispersion of optical signal brings about to generation of inter-symbol interface which influences the quality of optical fiber communication. In order to solve the above questions in the 40Gbps differential quarter phase-shift keying (DQPSK) optical fiber communication system, a new method of chromatic dispersion compensation based on genetic algorithm is proposed according to the demodulation of DQPSK optical signal and the trait of chromatic dispersion. Result shows that the system's receiving sensitivity has been enhanced up to six orders of magnitude.

Liu, Chun-wu; Qin, Jiang-yi; Huang, Zhi-ping; Zhang, Yi-meng

2013-08-01

12

Control algorithms for aerobraking in the Martian atmosphere  

NASA Astrophysics Data System (ADS)

The Analytic Predictor Corrector (APC) and Energy Controller (EC) atmospheric guidance concepts have been adapted to control an interplanetary vehicle aerobraking in the Martian atmosphere. Changes are made to the APC to improve its robustness to density variations. These modifications include adaptation of a new exit phase algorithm, an adaptive transition velocity to initiate the exit phase, refinement of the reference dynamic pressure calculation and two improved density estimation techniques. The modified controller with the hybrid density estimation technique is called the Mars Hybrid Predictor Corrector (MHPC), while the modified controller with a polynomial density estimator is called the Mars Predictor Corrector (MPC). A Lyapunov Steepest Descent Controller (LSDC) is adapted to control the vehicle. The LSDC lacked robustness, so a Lyapunov tracking exit phase algorithm is developed to guide the vehicle along a reference trajectory. The equilibrium glide entry phase is used for the first part of the trajectory. This algorithm, when using the hybrid density estimation technique to define the reference path, is called the Lyapunov Hybrid Tracking Controller (LHTC). With the polynomial density estimator used to define the reference trajectory, the algorithm is called the Lyapunov Tracking Controller (LTC). These four new controllers are tested using a six degree of freedom computer simulation to evaluate their robustness. MARS-GRAM is used to develop realistic atmospheres for the study. The atmospheres are then perturbed using square wave density pulses. The MHPC, MPC, LHTC and LRC show dramatic improvements in robustness over the APC and EC. The MHPC, MPC, LHTC and LTC all complete the initial phase of testing (using square wave density pulses) with no failures. The second phase tests the MHPC, MPC, LHTC and LTC against atmospheres where the inbound and outbound density functions are different. Square wave density pulses are again used, but only for the outbound leg of the trajectory. All four controllers are able to compensate for the outbound leg density pulses with no hard failures, but the algorithms are sensitive to large amplitude density pulses.

Shipley, Buford Wiley, Jr.

1991-02-01

13

Error compensation algorithm for patient positioning robotics system  

NASA Astrophysics Data System (ADS)

Surgeons in various medical areas (orthopedic surgery, neurosurgery, dentistry etc.) are using motor-driven drilling tools to make perforations in hard tissues (bone, enamel, dentine, cementum etc.) When the penetration requires very precise angles and accurate alignment with respect to different targets, precision cannot be obtained by using visual estimation and hand-held tools. Robots have been designed to allow for very accurate relative positioning of the patient and the surgical tools, and in certain classes of applications the location of bone target and inclination of the surgical tool can be accurately specified with respect to an inertial frame of reference. However, patient positioning errors as well as position changes during surgery can jeopardize the precision of the operation, and drilling parameters have to be dynamically adjusted. In this paper the authors present a quantitative method to evaluate the corrected position and inclination of the drilling tool, to account for translational and rotational errors in displaced target position. The compensation algorithm applies principles of inverse kinematics wherein a faulty axis in space caused by the translational and rotational errors of the target position is identified with an imaginary true axis in space by enforcing identity through a modified trajectory. In the absence of any specific application, this algorithm is verified on Solid Works, a commercial CAD tool and found to be correct. An example problem given at the end vindicates this statement.

Murty, Pilaka V.; Talpasanu, Ilie; Roz, Mugur A.

2009-03-01

14

Water Vapor Retrieval Using the FLAASH Atmospheric Correction Algorithm.  

National Technical Information Service (NTIS)

FLAASH (Fast Line-of-Sight Atmospheric Analysis of Spectral Hypercubes) is a first-principles atmospheric correction algorithm for visible to shortwave infrared (SWIR) hyperspectral data. The algorithm consists of two main steps. The first is retrieval of...

G. W. Felde G. P. Anderson J. A. Gardner S. M. Alder- Golden M. W. Matthew

2004-01-01

15

Atmospheric Correction Algorithm for Hyperspectral Imagery  

SciTech Connect

In December 1997, the US Department of Energy (DOE) established a Center of Excellence (Hyperspectral-Multispectral Algorithm Research Center, HyMARC) for promoting the research and development of algorithms to exploit spectral imagery. This center is located at the DOE Remote Sensing Laboratory in Las Vegas, Nevada, and is operated for the DOE by Bechtel Nevada. This paper presents the results to date of a research project begun at the center during 1998 to investigate the correction of hyperspectral data for atmospheric aerosols. Results of a project conducted by the Rochester Institute of Technology to define, implement, and test procedures for absolute calibration and correction of hyperspectral data to absolute units of high spectral resolution imagery will be presented. Hybrid techniques for atmospheric correction using image or spectral scene data coupled through radiative propagation models will be specifically addressed. Results of this effort to analyze HYDICE sensor data will be included. Preliminary results based on studying the performance of standard routines, such as Atmospheric Pre-corrected Differential Absorption and Nonlinear Least Squares Spectral Fit, in retrieving reflectance spectra show overall reflectance retrieval errors of approximately one to two reflectance units in the 0.4- to 2.5-micron-wavelength region (outside of the absorption features). These results are based on HYDICE sensor data collected from the Southern Great Plains Atmospheric Radiation Measurement site during overflights conducted in July of 1997. Results of an upgrade made in the model-based atmospheric correction techniques, which take advantage of updates made to the moderate resolution atmospheric transmittance model (MODTRAN 4.0) software, will also be presented. Data will be shown to demonstrate how the reflectance retrieval in the shorter wavelengths of the blue-green region will be improved because of enhanced modeling of multiple scattering effects.

R. J. Pollina

1999-09-01

16

Adaptive PMD compensation using DPSO algorithm for high-speed optical fibre communication systems  

NASA Astrophysics Data System (ADS)

We proposed an adaptive PMD compensation scheme based on FPGA using DPSO algorithm. Stable polarization compensation for 43Gbit/s RZ-DQPSK transmission over 1200km was demonstrated with endless polarization scrambling. Excellent performance was accomplished utilizing our scheme in case of changing SOP and DGD in longhaul fibre link.

Zhang, Jinnan; Zhang, Yangan; Weng, Xuan; Yuan, Xueguang; Lin, Mi; Jinjing, Tao; Zhang, Xiaoguang

2010-12-01

17

Dynamic Analysis of the Low Power Atmospheric Compensation Experiment (LACE) Spacecraft.  

National Technical Information Service (NTIS)

The Low Power Atmospheric Compensation Experiment (LACE) spacecraft was launched for NRL in February 1990. The LACE flight dynamics experiment will provide on-orbit systems identification of the LACE spacecraft. The experiment is designed to measure modal...

W. F. Walters

1990-01-01

18

CEMERLL: The Propagation of an Atmospheric-compensated Laser Beam to the Apollo 15 Lunar Array  

Microsoft Academic Search

Adaptive optics techniques can be used to realize a robust low bit-error-rate link by mitigating the atmosphere-induced signal fades in optical communications links between ground-based transmitters and deep-space probes. Phase I of the Compensated Earth-Moon-Earth Retroreflector Laser Link (CEMERLL) experiment demonstrated the first propagation of atmosphere-compensated laser beam to the lunar retroreflectors. A 1.06 µm Nd:YAG laser beam was propagated

K. E. Wilson; P. R. Leatherman; R. Cleis; J. Spinhirne; R. Q. Fugate

19

Bias Compensation for Least-Squares MultiPulse TDOA Localization Algorithms  

Microsoft Academic Search

A weighted least squares (WLS) estimator is presented for time difference of arrival (TDOA) localization of an emitter using multiple TDOA measurements collected by moving receivers. A comprehensive bias analysis for this estimate is provided. Based on the outcomes of the bias analysis, a bias compensation algorithm is developed to reduce the severe WLS estimation bias. The proposed algorithm utilizes

K. Dogancay; Douglas A. Gray

2005-01-01

20

Phase compensating algorithm investigation of real-time adaptive femtosecond pulse shaping  

NASA Astrophysics Data System (ADS)

Based on the real-time adaptive femtosecond pulse shaping system, the phase compensating algorithms which can effectively compensate the output shaping waveform distortions are investigated in detail. The simulated-annealing algorithm that can modify the output pulse temporal waveforms iteratively toward the target shapes using the second harmonic generating frequency resolved optical gating (SHG-FROG) measurement as feedback is proposed. Compared with the cross-correlation feedback measurement method, the output based on the SHG-FROG measurement method is better and the temporal chirp of the output pulse is compensated more effectively. Moreover the performance of the SHG-FROG measurement feedback algorithm is compared to other exemplary standard approaches such as the Genetic Algorithm based on the cross-correlation feedback measurement method, the result is much better.

Lou, Xin; Sun, Tie-ju; Duan, Fang-zhen; Yang, Xue-hua; Nie, Yong-ming

2013-09-01

21

A new control algorithm for three-phase PWM buck rectifier with input displacement factor compensation  

Microsoft Academic Search

A new control algorithm for the three-phase buck rectifier with an input filter is developed. The algorithm employs a separate control loop for compensation of the input current displacement factor in steady-state, in addition to the standard output voltage regulation loop. The algorithm allows separate design of the input filter and of closed-loop output voltage control. The design procedure is

S. Hiti; V. Vlatkovic; D. Borojevic; F. C. Y. Lee

1994-01-01

22

Structural design of optically compensated zoom lenses using genetic algorithm  

NASA Astrophysics Data System (ADS)

A new approach for structural synthesis of optically compensated zoom lenses is reported. An implementation of evolutionary programming facilitates the procedure by carrying out a global search over the available degrees of freedom, namely, powers of the components and the inter-component separations. Practical success of the method depends on suitable formulation of the fitness function. Normalization of the variables is carried out to get an insight on the optimum structures. Illustrative numerical results are presented.

Pal, S.; Hazra, L. N.

2009-08-01

23

Optimization of Reactive Power Compensation and Voltage Regulation Using Artificial Immune Algorithm for Radial Transmission Networks  

Microsoft Academic Search

This paper addresses the problem of optimal settings of reactive power compensation and bus voltage regulation. To be able to solve the problem for real-world cases, the artificial immune algorithm (AIA) technique is used to generate an optimal or near-optimal control strategy for reactive power compensation and bus voltage regulation. Two real-world cases are tested to demonstrate the effectiveness and

Tsair-Fwu Lee; Ying-Chang Hsiao; Horng-Yuan Wu; Tsair-Fwu Huang; Fu-Min Fang; Ming-Yuan Cho

2007-01-01

24

Adaptive filter design based on the LMS algorithm for delay elimination in TCR/FC compensators.  

PubMed

Thyristor controlled reactor with fixed capacitor (TCR/FC) compensators have the capability of compensating reactive power and improving power quality phenomena. Delay in the response of such compensators degrades their performance. In this paper, a new method based on adaptive filters (AF) is proposed in order to eliminate delay and increase the response of the TCR compensator. The algorithm designed for the adaptive filters is performed based on the least mean square (LMS) algorithm. In this design, instead of fixed capacitors, band-pass LC filters are used. To evaluate the filter, a TCR/FC compensator was used for nonlinear and time varying loads of electric arc furnaces (EAFs). These loads caused occurrence of power quality phenomena in the supplying system, such as voltage fluctuation and flicker, odd and even harmonics and unbalancing in voltage and current. The above design was implemented in a realistic system model of a steel complex. The simulation results show that applying the proposed control in the TCR/FC compensator efficiently eliminated delay in the response and improved the performance of the compensator in the power system. PMID:21193194

Hooshmand, Rahmat Allah; Torabian Esfahani, Mahdi

2010-12-28

25

A new control algorithm for three-phase PWM buck rectifier with input displacement factor compensation  

SciTech Connect

A new control algorithm for the three-phase buck rectifier with an input filter is developed. The algorithm employs a separate control loop for compensation of the input current displacement factor in steady-state, in addition to the standard output voltage regulation loop. The algorithm allows separate design of the input filter and of closed-loop output voltage control. The design procedure is explained and illustrated with an example. The algorithm is verified experimentally on a 1 kW, 100 kHz, three-phase isolated buck converter.

Hiti, S.; Vlatkovic, V.; Borojevic, D.; Lee, F.C.Y. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Bradley Dept. of Electrical Engineering)

1994-03-01

26

Global motion-compensated preprocessing algorithm for block-based frame-rate conversion  

NASA Astrophysics Data System (ADS)

We propose a global motion (GM) compensated preprocessing algorithm for block-based frame rate conversion (FRC). The proposed method estimates camera motions such as zooms or rotations between two input frames, and accordingly, produces nontranslational GM-free pictures by performing GM compensation with respect to the temporal location where the FRC method reconstructs an intermediate frame. To reduce the computational load, the proposed method first subsamples input images, and then block-wise motion estimation (ME) is performed. With the ME results, the proposed method detects scene changes and nontranslational GMs. This allows us to determine whether to proceed with the GM estimation and compensation processes. The geometric motion model is adopted to describe camera motions with four parameters, and these values are iteratively found on a motion vector (MV) field. Experimental results show that the proposed algorithm achieves significant performance improvements of subsequent FRC methods.

Kim, Young Duk; Chang, Joonyoung; Gi Kang, Moon

2010-04-01

27

Hierarchy compensation of non-homogeneous intermittent atmospheric turbulence  

Microsoft Academic Search

In this work a study both the internal turbulence energy cascade intermittency evaluated from wind speed series in the atmospheric boundary layer, as well as the role of external or forcing intermittency based on the flatness (Vindel et al 2008)is carried out. The degree of intermittency in the stratified ABL flow (Cuxart et al. 2000) can be studied as the

Jose M. Redondo; Otman B. Mahjoub; Inma R. Cantalapiedra

2010-01-01

28

Algorithmic depth compensation improves quantification and noise suppression in functional diffuse optical tomography.  

PubMed

Accurate depth localization and quantitative recovery of a regional activation are the major challenges in functional diffuse optical tomography (DOT). The photon density drops severely with increased depth, for which conventional DOT reconstruction yields poor depth localization and quantitative recovery. Recently we have developed a depth compensation algorithm (DCA) to improve the depth localization in DOT. In this paper, we present an approach based on the depth-compensated reconstruction to improve the quantification in DOT by forming a spatial prior. Simulative experiments are conducted to demonstrate the usefulness of this approach. Moreover, noise suppression is a key to success in DOT which also affects the depth localization and quantification. We present quantitative analysis and comparison on noise suppression in DOT with and without depth compensation. The study reveals that appropriate combination of depth-compensated reconstruction with the spatial prior can provide accurate depth localization and improved quantification at variable noise levels. PMID:21258479

Tian, Fenghua; Niu, Haijing; Khadka, Sabin; Lin, Zi-Jing; Liu, Hanli

2010-08-02

29

Algorithmic depth compensation improves quantification and noise suppression in functional diffuse optical tomography  

PubMed Central

Accurate depth localization and quantitative recovery of a regional activation are the major challenges in functional diffuse optical tomography (DOT). The photon density drops severely with increased depth, for which conventional DOT reconstruction yields poor depth localization and quantitative recovery. Recently we have developed a depth compensation algorithm (DCA) to improve the depth localization in DOT. In this paper, we present an approach based on the depth-compensated reconstruction to improve the quantification in DOT by forming a spatial prior. Simulative experiments are conducted to demonstrate the usefulness of this approach. Moreover, noise suppression is a key to success in DOT which also affects the depth localization and quantification. We present quantitative analysis and comparison on noise suppression in DOT with and without depth compensation. The study reveals that appropriate combination of depth-compensated reconstruction with the spatial prior can provide accurate depth localization and improved quantification at variable noise levels.

Tian, Fenghua; Niu, Haijing; Khadka, Sabin; Lin, Zi-Jing; Liu, Hanli

2010-01-01

30

Compensation of intra-channel nonlinear fibre impairments using simplified digital back-propagation algorithm.  

PubMed

We investigate a digital back-propagation simplification method to enable computationally-efficient digital nonlinearity compensation for a coherently-detected 112 Gb/s polarization multiplexed quadrature phase shifted keying transmission over a 1,600 km link (20 x 80 km) with no inline compensation. Through numerical simulation, we report up to 80% reduction in required back-propagation steps to perform nonlinear compensation, in comparison to the standard back-propagation algorithm. This method takes into account the correlation between adjacent symbols at a given instant using a weighted-average approach, and optimization of the position of nonlinear compensator stage to enable practical digital back-propagation. PMID:21643203

Rafique, Danish; Mussolin, Marco; Forzati, Marco; Mårtensson, Jonas; Chugtai, Mohsan N; Ellis, Andrew D

2011-05-01

31

A Cascade Algorithm for Estimating and Compensating Motion Error for Synthetic Aperture Sonar Imaging  

Microsoft Academic Search

This paper presents a three-level cascade algorithm for estimating and compensating platform motion errors during synthetic aperture sonar imaging. By using a multiple element receiving array, physical aperture images can be produced from each transmit burst. With proper spatial sampling, there is sufficient redundancy in successive physical aperture images to extract motion parameters that can be applied to the image

John M. Silkaitis; Brett L. Douglas; Hua Lee

1994-01-01

32

Hierarchical motion-compensated interframe DPCM algorithm for low-bit-rate coding  

Microsoft Academic Search

The block-based motion estimation algorithm we have previously proposed possesses the advantages of a high estimation accuracy and a good prediction performance. It can efficiently be employed in a motion-compensated DPCM coder to minimize the data bits for the transmission of prediction errors. However, the motion overhead data rate, although it has been compressed dramatically by the coding method we

Kan Xie; Luc van Eycken; Andre J. Oosterlinck

1991-01-01

33

Optimization algorithm in adaptive PMD compensation in 10Gb/s optical communication system  

NASA Astrophysics Data System (ADS)

In this paper, the optimization algorithms are introduced in adaptive PMD compensation in 10Gb/s optical communication system. The PMD monitoring technique based on degree of polarization (DOP) is adopted. DOP can be a good indicator of PMD with monotonically deceasing of DOP as differential group delay (DGD) increasing. In order to use DOP as PMD monitoring feedback signal, it is required to emulate the state of DGD in the transmission circuitry. A PMD emulator is designed. A polarization controller (PC) is used in fiber multiplexer to adjust the polarization state of optical signal, and at the output of the fiber multiplexer a polarizer is used. After the feedback signal reach the control computer, the optimization program run to search the global optimization spot and through the PC to control the PMD. Several popular modern nonlinear optimization algorithms (Tabu Search, Simulated Annealing, Genetic Algorithm, Artificial Neural Networks, Ant Colony Optimization etc.) are discussed and the comparisons among them are made to choose the best optimization algorithm. Every algorithm has its advantage and disadvantage, but in this circs the Genetic Algorithm (GA) may be the best. It eliminates the worsen spots constantly and lets them have no chance to enter the circulation. So it has the quicker convergence velocity and less time. The PMD can be compensated in very few steps by using this algorithm. As a result, the maximum compensation ability of the one-stage PMD and two-stage PMD can be made in very short time, and the dynamic compensation time is no more than 10ms.

Diao, Cao; Li, Tangjun; Wang, Muguang; Gong, Xiangfeng

2005-02-01

34

Springback Simulation and Tool Surface Compensation Algorithm for Sheet Metal Forming  

SciTech Connect

Springback is an unquenchable forming defect in the sheet metal forming process. How to calculate springback accurately is a big challenge for a lot of FEA software. Springback compensation makes the stamped final part accordant with the designed part shape by modifying tool surface, which depends on the accurate springback amount. How ever, the meshing data based on numerical simulation is expressed by nodes and elements, such data can not be supplied directly to tool surface CAD data. In this paper, a tool surface compensation algorithm based on numerical simulation technique of springback process is proposed in which the independently developed dynamic explicit springback algorithm (DESA) is used to simulate springback amount. When doing the tool surface compensation, the springback amount of the projected point can be obtained by interpolation of the springback amount of the projected element nodes. So the modified values of tool surface can be calculated reversely. After repeating the springback and compensation calculations for 1{approx}3 times, the reasonable tool surface mesh is gained. Finally, the FEM data on the compensated tool surface is fitted into the surface by CAD modeling software. The examination of a real industrial part shows the validity of the present method.

Shen Guozhe; Hu Ping; Zhang Xiangkui; Chen Xiaobin; Li Xiaoda [Institute of Auto-body and Die Engineering in State Key Lab of Automobile Dynamic Simulation, Jilin University, 130025, Changchun (China)

2005-08-05

35

Performance assessment of ACORN atmospheric correction algorithm  

Microsoft Academic Search

The ACORN atmospheric correction routine was evaluated using criteria established in a precious performance assessment effort. The data utilized in this analysis represented a variety of background and atmospheric conditions, and were collected by the HYDICE imaging spectrometer. The baseline technique used to match retrieved reflectance spectra with ground truth was the matched filter with the bad bands deleted. Additional

Craig J. Miller

2002-01-01

36

Compensation of atmospheric CO2 buildup through engineered chemical sinkage  

NASA Astrophysics Data System (ADS)

Retrieval of background carbon dioxide into regional chemical extractors would counter anthropogenic inputs in a manner friendly to established industries. We demonstrate via atmospheric transport/scaling calculations that for idealized flat removal units, global coverage could be less than two hundred thousand square kilometers. The disrupted area drops to a small fraction of this with engineering into the vertical to bypass laminarity. Fence structures and artificial roughness elements can both be conceived. Sink thermodynamics are analyzed by taking calcium hydroxide as a sample reactant. Energy costs could be minimized at near the endothermicity of binding reversal. In the calcium case the value is 25 kcal mole-1, as against a fuel carbon content of 150 in the same units. Aqueous kinetics are less than favorable for the hydroxide, but misting could counteract slow liquid phase transfer. Properties of superior scrubbers are outlined.

Elliott, S.; Lackner, K. S.; Ziock, H. J.; Dubey, M. K.; Hanson, H. P.; Barr, S.; Ciszkowski, N. A.; Blake, D. R.

37

Novel true-motion estimation algorithm and its application to motion-compensated temporal frame interpolation.  

PubMed

In this paper, a new low-complexity true-motion estimation (TME) algorithm is proposed for video processing applications, such as motion-compensated temporal frame interpolation (MCTFI) or motion-compensated frame rate up-conversion (MCFRUC). Regular motion estimation, which is often used in video coding, aims to find the motion vectors (MVs) to reduce the temporal redundancy, whereas TME aims to track the projected object motion as closely as possible. TME is obtained by imposing implicit and/or explicit smoothness constraints on the block-matching algorithm. To produce better quality-interpolated frames, the dense motion field at interpolation time is obtained for both forward and backward MVs; then, bidirectional motion compensation using forward and backward MVs is applied by mixing both elegantly. Finally, the performance of the proposed algorithm for MCTFI is demonstrated against recently proposed methods and smoothness constraint optical flow employed by a professional video production suite. Experimental results show that the quality of the interpolated frames using the proposed method is better when compared with the MCFRUC techniques. PMID:23060328

Dikbas, Salih; Altunbasak, Yucel

2012-10-04

38

ENHANCEMENTS TO AN ATMOSPHERIC ASCENT GUIDANCE ALGORITHM  

Microsoft Academic Search

Enhancements to an advanced ascent guidance algorithm for rocket-powered launch vehicles are described. A general method has been developed for conveniently and efficiently handling the common case of (asymmetric) launch vehicles with unbalanced thrust and aerodynamic moments. The new part of this development concerns the treatment of endo-atmosperic flight. An alternative method for handing the transversality conditions has been developed

Greg A. Dukeman

39

A fast algorithm for DCT-domain inverse motion compensation based on shared information in a macroblock  

Microsoft Academic Search

The ability to construct intracoded frame from motion-compensated intercoded frames directly in the com- pressed domain is important for efficient video manipulation and composition. In the context of motion-compensated discrete cosine transform (DCT)-based coding of video as in MPEG video, this problem of DCT-domain inverse motion compensation has been studied and, subsequently, improved faster algorithms were proposed. These schemes, however,

Junehwa Song; Boon-lock Yeo

2000-01-01

40

Note: atmospheric point discharge current measurements using a temperature-compensated logarithmic current amplifier.  

PubMed

Measurements of atmospheric corona currents have been made for over 100 years to indicate the atmospheric electric field. Corona currents vary substantially, in polarity and in magnitude. The instrument described here uses a sharp point sensor connected to a temperature compensated bi-polar logarithmic current amplifier. Calibrations over a range of currents from ±10 fA to ±3 ?A and across ±20 °C show it has an excellent logarithmic response over six orders of magnitude from 1 pA to 1 ?A in both polarities for the range of atmospheric temperatures likely to be encountered in the southern UK. Comparison with atmospheric electric field measurements during disturbed weather confirms that bipolar electric fields induce corona currents of corresponding sign, with magnitudes ~0.5 ?A. PMID:23822390

Marlton, G J; Harrison, R G; Nicoll, K A

2013-06-01

41

Deep Pacific CaCO 3 compensation and glacial-interglacial atmospheric CO 2  

NASA Astrophysics Data System (ADS)

Benthic foraminiferal ?13C suggests that there was a net shift of isotopically light metabolic CO 2 from the upper ocean into the deep ocean during the last glacial period. According to the 'CaCO 3 compensation' hypothesis, this should have caused a transient drop in deep ocean CO 32- that was eventually reversed by seafloor dissolution of CaCO 3. The resulting increase in whole-ocean pH may have had a significant impact on atmospheric CO 2, compounding any decrease that was due to the initial vertical CO 2 shift. The opposite hypothetically occurred during deglaciation, when CO 2 was returned to the upper ocean (and atmosphere) and deep ocean CO 32- temporarily increased, followed by excess burial of CaCO 3 and a drop in whole-ocean pH. The deep sea record of CaCO 3 preservation appears to reflect these processes, with the largest excursion during deglaciation (as expected), but various factors make quantification of deep sea paleo-CO 32- difficult. Here we reconstruct deep equatorial Pacific CO 32- over the last glacial-interglacial cycle using benthic foraminiferal Zn/Ca, which is strongly affected by saturation state during calcite precipitation. Our data are in agreement with the CaCO 3 compensation theory, including glacial CO 32- concentrations similar to (or slightly lower than) today, and a Termination I CO 32- peak of ˜25-30 ?mol kg -1. The deglacial CO 32- rise precedes ice sheet melting, consistent with the timing of the atmospheric CO 2 rise. A later portion of the peak could reflect removal of CO 2 from the atmosphere-ocean system due to boreal forest regrowth. CaCO 3 compensation alone may explain more than one third of the atmospheric CO 2 lowering during glacial times.

Marchitto, Thomas M.; Lynch-Stieglitz, Jean; Hemming, Sidney R.

2005-03-01

42

Quadratic phase error compensation algorithm based on phase cancellation for ISAIL  

NASA Astrophysics Data System (ADS)

As a product combining inverse synthetic aperture technology with coherent laser technology, Inverse Synthetic Aperture Imaging Ladar (ISAIL) overcomes the diffraction limit of the telescope's aperture, while it supplies a much better range resolution which will not get worse at long range when the diameter telescope optics becomes smaller. Compared with traditional microwave imaging radar, SAIL can provide a much higher-resolution image because of shorter wavelength, and its shorter imaging time for coherent integration takes a great part in practical application. The rotational motion of target generates Migration through Range Cells (MTRC) because of the ultra-high resolution of ISAIL. Quadratic Phase Error (QPE) caused by Migration through Range Cells (MTRC) during the imaging time makes ISAIL image smeared. It is difficult to estimate the QPE through traditional motion compensation algorithm. To solve this problem in the case of uniform rotation rate, a novel QPE compensation method, based on Phase Cancellation (PC), is proposed. Firstly, a rough range of QPE coefficient related to the wave-length, length of the target, and the rotating angle is estimated. Then, through 1-D search, the QPE coefficient is obtained exactly. Finally, the QPE compensation is achieved. The ISAIL imaging experiments with numerical data validate the feasibility and effectiveness of the proposed algorithm.

Zang, Bo; Li, Qi; Ji, Hong-Bing; Tang, Yu

2013-09-01

43

Comprehensive investigation of three-dimensional diffuse optical tomography with depth compensation algorithm.  

PubMed

A depth compensation algorithm (DCA) can effectively improve the depth localization of diffuse optical tomography (DOT) by compensating the exponentially decreased sensitivity in the deep tissue. In this study, DCA is investigated based on computer simulations, tissue phantom experiments, and human brain imaging. The simulations show that DCA can largely improve the spatial resolution of DOT in addition to the depth localization, and DCA is also effective for multispectral DOT with a wide range of optical properties in the background tissue. The laboratory phantom experiment demonstrates that DCA can effectively differentiate two embedded objects at different depths in the medium. DCA is further validated by human brain imaging using a finger-tapping task. To our knowledge, this is the first demonstration to show that DCA is capable of accurately localizing cortical activations in the human brain in three dimensions. PMID:20799807

Niu, Haijing; Lin, Zi-Jing; Tian, Fenghua; Dhamne, Sameer; Liu, Hanli

44

Development of a compensation algorithm for accurate depth localization in diffuse optical tomography.  

PubMed

Diffuse optical tomography endures poor depth localization, since its sensitivity decreases severely with increased depth. In this study, we demonstrate a depth compensation algorithm (DCA), which optimally counterbalances the decay nature of light propagation in tissue so as to accurately localize absorbers in deep tissue. The novelty of DCA is to directly modify the sensitivity matrix, rather than the penalty term of regularization. DCA is based on maximum singular values (MSVs) of layered measurement sensitivities; these MSVs are inversely utilized to create a balancing weight matrix for compensating the measurement sensitivity in increased depth. Both computer simulations and laboratory experiments were performed to validate DCA. These results demonstrate that one (or two) 3-cm-deep absorber(s) can be accurately located in both lateral plane and depth within the laboratorial position errors. PMID:20125744

Niu, Haijing; Tian, Fenghua; Lin, Zi-Jing; Liu, Hanli

2010-02-01

45

Comprehensive investigation of three-dimensional diffuse optical tomography with depth compensation algorithm  

PubMed Central

A depth compensation algorithm (DCA) can effectively improve the depth localization of diffuse optical tomography (DOT) by compensating the exponentially decreased sensitivity in the deep tissue. In this study, DCA is investigated based on computer simulations, tissue phantom experiments, and human brain imaging. The simulations show that DCA can largely improve the spatial resolution of DOT in addition to the depth localization, and DCA is also effective for multispectral DOT with a wide range of optical properties in the background tissue. The laboratory phantom experiment demonstrates that DCA can effectively differentiate two embedded objects at different depths in the medium. DCA is further validated by human brain imaging using a finger-tapping task. To our knowledge, this is the first demonstration to show that DCA is capable of accurately localizing cortical activations in the human brain in three dimensions.

Niu, Haijing; Lin, Zi-Jing; Tian, Fenghua; Dhamne, Sameer; Liu, Hanli

2010-01-01

46

Performance-metric driven atmospheric compensation for robust free-space laser communication  

NASA Astrophysics Data System (ADS)

Laser Communication (LaserCom) offers some profound advantages over RF-based systems, such as higher-bandwidth, lower power consumption, and lower probability of intercept. However, the effect of turbulence on laser propagation is a significant challenge to current electro-optical systems. While atmospheric compensation techniques in space object imaging and high-energy laser weapons have been thoroughly investigated, optimizing these techniques for LaserCom has not been examined to the same degree. This research investigates performance-metric driven atmospheric compensation techniques to improve reliability of free-space LaserCom systems. Several receiver-based techniques were developed and analyzed while considering constraints relevant to tactical airborne platforms. First, wavefront control techniques were considered. In a moderate range air-to-air scenario, focal plane image breakup is identified as the dominant failure mechanism causing deep fades. This led to investigation of peak intensity tracking, which reduces fade probability by greater than 50% over conventional centroid trackers and Adaptive Optics (AO) systems for scenarios studied. Second, atmospheric compensation requirements were examined based on deep fade phenomenology. Fades are classified based on complexity of the required compensation technique. For compensation techniques studied, regions of superior performance, in terms of fade probability, are identified. Peak tracking is shown to outperform AO for thresholds below approximately 4% of the unaberrated intensity. Furthermore, the boundary between superior performance regions is nearly invariant to turbulence strength. This boundary invariance simplifies operation of a composite system which is able to adaptively select compensation methodology in near real-time. An adaptive binary decision threshold is the third major focus of this research. Analytic results show that an adaptive threshold provides a bit-error rate improvement of up to 1.60 orders of magnitude (33-fold decrease) for a 10 Gbps link, and up to 0.56 orders of magnitude (3.6-fold decrease) for a 10 Mbps link. Adaptive thresholding yields improved performance without the additional cost, weight, and/or complexity of increasing source power, incorporating wavefront control at receiver, or incorporating AO at the transmitter.

Crabtree, Peter N.

47

The atmospheric correction algorithm for HY-1B/COCTS  

NASA Astrophysics Data System (ADS)

China has launched her second ocean color satellite HY-1B on 11 Apr., 2007, which carried two remote sensors. The Chinese Ocean Color and Temperature Scanner (COCTS) is the main sensor on HY-1B, and it has not only eight visible and near-infrared wavelength bands similar to the SeaWiFS, but also two more thermal infrared bands to measure the sea surface temperature. Therefore, COCTS has broad application potentiality, such as fishery resource protection and development, coastal monitoring and management and marine pollution monitoring. Atmospheric correction is the key of the quantitative ocean color remote sensing. In this paper, the operational atmospheric correction algorithm of HY-1B/COCTS has been developed. Firstly, based on the vector radiative transfer numerical model of coupled oceanatmosphere system- PCOART, the exact Rayleigh scattering look-up table (LUT), aerosol scattering LUT and atmosphere diffuse transmission LUT for HY-1B/COCTS have been generated. Secondly, using the generated LUTs, the exactly operational atmospheric correction algorithm for HY-1B/COCTS has been developed. The algorithm has been validated using the simulated spectral data generated by PCOART, and the result shows the error of the water-leaving reflectance retrieved by this algorithm is less than 0.0005, which meets the requirement of the exactly atmospheric correction of ocean color remote sensing. Finally, the algorithm has been applied to the HY-1B/COCTS remote sensing data, and the retrieved water-leaving radiances are consist with the Aqua/MODIS results, and the corresponding ocean color remote sensing products have been generated including the chlorophyll concentration and total suspended particle matter concentration.

He, Xianqiang; Bai, Yan; Pan, Delu; Zhu, Qiankun

2008-10-01

48

Development of an algorithm of absolute atmospheric correction for multitemporal satellite images. Application to the region of Oran (West of Algeria)  

Microsoft Academic Search

This paper presents an algorithm for modelling of the different parameters which influence the reflectance at the satellite's level in order to estimate the real reflectance of the objects at the ground surface. However, the model described would compensate the atmospheric effects, the irradiance and the observation conditions, and characterise the objects by their unique and real values. Thus, the

Z. Smahi; K. Benhanifia; A. Bensaid

1999-01-01

49

Simulation of atmospheric turbulence compensation through piston-only phase control of a laser phased array  

NASA Astrophysics Data System (ADS)

Beam propagation from a laser phased array system through the turbulent atmosphere is simulated and the ability of such a system to compensate for the atmosphere via piston-only phase control of the sub-apertures is evaluated. Directed energy (DE) applications demand more power than most lasers can produce, consequently many schemes for high power involve combining the beams from many smaller lasers into one. When many smaller lasers are combined into a phased array, phase control of the individual sub-apertures will be necessary to create a high-quality beam. Phase control of these sub-apertures could then be used to do more, such as focus, steer, and compensate for atmospheric turbulence. Atmospheric turbulence is well known to degrade the performance of both imaging systems and laser systems. Adaptive optics can be used to mitigate this degradation. Adaptive optics ordinarily involves a deformable mirror, but with phase control on each sub-aperture the need for a deformable mirror is eliminated. The simulation conducted here evaluates performance gain for a 127 element phased array in a hexagonal pattern with piston-only phase control on each element over an uncompensated array for varying levels of atmospheric turbulence. While most simulations were carried out against a 10 km tactical scenario, the turbulence profile was adjusted so performance could be evaluated as a function of the Fried Parameter (r0) and the log-amplitude variance somewhat independently. This approach is demonstrated to be generally effective with the largest percentage improvement occurring when r0 is close to the sub-aperture diameter.

McCrae, Jack E.; Van Zandt, Noah; Cusumano, Salvatore J.; Fiorino, Steven T.

2013-05-01

50

MTF compensation algorithm based on blind deconvolution for high-resolution remote sensing satellite  

NASA Astrophysics Data System (ADS)

In high resolution remote sensing satellite imaging system, image restoration is an important step to visualize ne details and mitigate the noise. The raw image data often presents poor imaging quality due to various reasons and Point Spread Function (PSF) measures such blurriness characteristic of the image using point source. Satellite image from Korea Multi-purpose Satellite 2 (KOMPSAT-2) also requires Modular Transfer Function (MTF) compensation process to achieve more realistic image which entails removing ringing artifacts at the edges and restraining excess use of denoising eect in order to keep it more realistic. This paper focuses on the deconvolution of KOMPSAT-2 image utilizing PSF attained from Korea Aerospace Research Institute compared to deconvolution with the estimated PSF blur kernel. The deconvolution algorithm considered are Richard-Lucy, Damped Richard-Lucy, Bilateral Richard-Lucy and Sparse Prior deconvolution algorithms.

Lee, Jihye; Chun, Joohwan; Lee, Donghwan

2012-05-01

51

The algorithm of regionally compensating nonlinear response of photo detector to improve the quality of image reconstruction for compressed sensing  

NASA Astrophysics Data System (ADS)

In imaging systems based on compressed sensing, error in the measured data is incurred due to the nonlinear response of the photo-detector, which affects the quality of reconstructed images. Conventionally, the affected measured data will be eliminated in order to obtain the high reconstruction quality. However, when there are too many measured data affected, it is impossible to reject all such data which will certainly degrade the imaging efficiency. Therefore, an algorithm of regionally compensating the non-linear response from the detector is proposed. The nonlinear measured data will be compensated but not rejected in the proposed algorithm. According to the detector response curve, all of the nonlinear measured data will be divided into several parts. The data in the same part will have the same average compensation factor which can be obtained from the response curve after calculation. The affected measured data will be compensated with the compensation factor regionally before used to reconstruct the original image. The theoretical analysis and simulation results show that a reconstructed image with high quality can still be obtained even when over 80% of the measured data are nonlinear. It is impossible to get such a high quality reconstructed image with the conventionally algorithm. The PSNR and the M-rate in the simulation show that the compensation algorithm can greatly deal with the situation of too many nonlinear measured data.

Zhuang, Jiayan; Chen, Qian; Miao, Zhuang; He, Weiji; Feng, Weiyi

2013-08-01

52

Acceleration of motion-compensated PET reconstruction: ordered subsets-gates EM algorithms and a priori reference gate information  

Microsoft Academic Search

Patient motion during positron emission tomography scans leads to significant resolution loss and image degradation. Motion-compensated image reconstruction (MCIR) algorithms have proven to be reliable correction methods given accurate deformation fields. However, although ordered subsets (OS) are widely used to speed up the convergence, OS-MCIR algorithms are still computationally expensive. This study concentrates on acceleration of OS-MCIR algorithms through two

N. Dikaios; T. D. Fryer

2011-01-01

53

New algorithm for atmospheric correction of hyperspectral remote sensing data  

NASA Astrophysics Data System (ADS)

We previously developed an algorithm for remote sensing of ocean color from space that allows quick atmospheric correction of hyperspectral data using lookup tables generated with a modified version of Ahmad & Fraser's vector radiative transfer code. During the past year we extended our radiative transfer calculations, allowing us to generate tables for several airborne altitudes. We also modified our lookup-table software to interpolate to sensor altitudes between those specified in the new tables. Here, we present results of atmospheric corrections using the new tables and software on hyperspectral imagery collected with NRL's recent PHILLS instrument and past AVIRIS flights.

Montes, Marcos J.; Gao, Bo-Cai; Davis, Curtiss O.

2001-06-01

54

Application of genetic algorithm in atmospheric carbon dioxide concentration retrieval  

NASA Astrophysics Data System (ADS)

This paper introduces the basic theory and method of carbon dioxide (CO2) retrieval. The key step is to search for the optimal solution and the random search algorithm Genetic Algorithm (GA) which can effectively avoid the local optimization. We first investigate the basic principles of GA in CO2 retrieval and then design the corresponding encoding and decoding methods as well as the fitness function. This newly-developed GA is further applied to retrieve the atmospheric CO2 concentration using Atmospheric Infrared Sounder (AIRS) observations from January 2006 to December 2008 centered at 20°N, 144°E. Compared to the aircraft measurements, the GA retrieval yields the small root mean square error of 1.13 ppmv and reproduces good results with the observed seasonal cycle.

Li, Jingyao; Shi, Runhe; Gao, Wei

2013-09-01

55

Adaptive optics compensation of atmospheric turbulence: the past, the present, and the promise  

NASA Astrophysics Data System (ADS)

An overview of adaptive optics systems development is presented with emphasis on its power to compensate for atmospheric turbulence in imaging and laser propagation. A brief history from the conceptual thinking in the 1950s through laboratory implementation in the 1970s to practical reality in the 1990s will be covered. With ongoing research to solve the problem of atmospheric anisoplanatism, the use of artificial guide stars has become as a prominent point of discussion. The understanding of the artificial guide star phenomena and advances in laser technology are bringing systems from the research and technology development mode into systems with scientific utility. Conflicting technical limitations of guide star brightness, laser psoower, and compensation spatial frequency are traded to achieve the most scientific benefit with the least cost. a summary ore recent results from operating adaptive optics systems in observatories around the world will be followed by a brief look at the future promise of adaptive optics in the commercia sector, including requirements of mass market systems for the amateur astronomer.

Tyson, Robert K.

1994-06-01

56

Control algorithms for aerobraking in the Martian atmosphere  

NASA Astrophysics Data System (ADS)

The Analytic Predictor Corrector (APC) and Energy Controller (EC) atmospheric guidance concepts were adapted to control an interplanetary vehicle aerobraking in the Martian atmosphere. Changes are made to the APC to improve its robustness to density variations. These changes include adaptation of a new exit phase algorithm, an adaptive transition velocity to initiate the exit phase, refinement of the reference dynamic pressure calculation and two improved density estimation techniques. The modified controller with the hybrid density estimation technique is called the Mars Hybrid Predictor Corrector (MHPC), while the modified controller with a polynomial density estimator is called the Mars Predictor Corrector (MPC). A Lyapunov Steepest Descent Controller (LSDC) is adapted to control the vehicle. The LSDC lacked robustness, so a Lyapunov tracking exit phase algorithm is developed to guide the vehicle along a reference trajectory. This algorithm, when using the hybrid density estimation technique to define the reference path, is called the Lyapunov Hybrid Tracking Controller (LHTC). With the polynomial density estimator used to define the reference trajectory, the algorithm is called the Lyapunov Tracking Controller (LTC). These four new controllers are tested using a six degree of freedom computer simulation to evaluate their robustness. The MHPC, MPC, LHTC, and LTC show dramatic improvements in robustness over the APC and EC.

Ward, Donald T.; Shipley, Buford W., Jr.

1991-09-01

57

Control algorithms for aerobraking in the Martian atmosphere  

NASA Astrophysics Data System (ADS)

The Analytic Predictor Corrector (APC) and Energy Controller (EC) atmospheric guidance concepts have been adapted to control an interplanetary vehicle aerobraking in the Martian atmosphere. Modifications are made to the APC to improve its robustness to density variations. These modifications include adaptation of a new exit phase algorithm, an adaptive transition velocity to initiate the exit phase, refinement of the reference dynamic pressure calculation and two hybrid density estimation techniques. The modified controller with the hybrid density estimation technique is called the Mars Hybrid Predictor Corrector (MHPC), while the modified controller with a polynomial density estimator is called the Mars Predictor Corrector (MPC). A Lyapunov Steepest Descent Controller (LSDC) is adapted to control the vehicle. The LSDC lacked robustness, so a Lyapunov tracking exit phase algorithm is developed to guide the vehicle along a reference trajectory. The equilibrium glide entry phase is employed for the first part of the trajectory. This algorithm, when using the hybrid density estimation technique to define the reference path, is called te Lyapunov Hybrid Tracking Controller (LHTC). With the polynomial density estimator used to define the reference trajectory, the algorithm is called the Lyapunov Tracking Controller (LTC). The four new controllers are tested usig a six degree of freedom computer simulation to evaluate their robustness.

Shipley, Buford W., Jr.

1991-12-01

58

Aerosol Retrieval and Atmospheric Correction Algorithms for EPIC  

NASA Astrophysics Data System (ADS)

EPIC is a multi-spectral imager onboard planned Deep Space Climate ObserVatoRy (DSCOVR) designed for observations of the full illuminated disk of the Earth with high temporal and coarse spatial resolution (10 km) from Lagrangian L1 point. During the course of the day, EPIC will view the same Earth surface area in the full range of solar and view zenith angles at equator with fixed scattering angle near the backscattering direction. This talk will describe a new aerosol retrieval/atmospheric correction algorithm developed for EPIC and tested with EPIC Simulator data. This algorithm uses the time series approach and consists of two stages: the first stage is designed to periodically re-initialize the surface spectral bidirectional reflectance (BRF) on stable low AOD days. Such days can be selected based on the same measured reflectance between the morning and afternoon reciprocal view geometries of EPIC. On the second stage, the algorithm will monitor the diurnal cycle of aerosol optical depth and fine mode fraction based on the known spectral surface BRF. Testing of the developed algorithm with simulated EPIC data over continental USA showed a good accuracy of AOD retrievals (10-20%) except over very bright surfaces.

Wang, Y.; Lyapustin, A.; Marshak, A.; Korkin, S.; Herman, J. R.

2011-12-01

59

Novel algorithm to compensate nonlinear response of photo detector to improve quality of image reconstruction for compressed sensing  

NASA Astrophysics Data System (ADS)

In imaging systems based on compressed sensing, error in the measured data is incurred due to the nonlinear response of the photo detector, which affects the quality of the reconstructed images. We propose an algorithm to compensate the nonlinear response from the detector. The compensation is based on the detector response curve on the measured data. The theoretical analysis and simulation results show that this algorithm can greatly reduce the reconstruction errors caused by the detector's nonlinear response. Furthermore the peak signal-to-noise ratio of the reconstructed image and the system reconstruction rate have been significantly improved, while the fine feature of the images is better preserved and reconstructed as compared to that without using the algorithm.

Zhuang, Jiayan; Chen, Qian; He, Weiji; Feng, Weiyi

2013-04-01

60

A series-connected voltage source converter for voltage sag mitigation using vector control and a filter compensation algorithm  

Microsoft Academic Search

In this paper, a series-connected VSC for voltage sag mitigation is presented, which is characterized by a fast control logic, based on the decomposition of the unbalanced supply voltages into instantaneous positive and negative sequence components in two different rotating dq-coordinate systems. Furthermore, its performance is improved through the implementation of an algorithm to compensate for the steady-state voltage drop

Ambra Sannino; Jan Svensson

2000-01-01

61

Phase measurement and error analysis in the arc-tangent method using a novel phase-compensating algorithm  

NASA Astrophysics Data System (ADS)

Many applications related to measurements use sinusoidal waves such as acoustic and electromagnetic waves. In particular, the phase information of sinusoidal waves is frequently used in several sensors. However, it is difficult to extract the phase information exactly, and many operations are consequently demanded. Among the operations, the arc-tangent method is very useful to measure the phase of a sinusoidal signal. This method, however, has a limitation that the initial phase difference between two sinusoidal signals must be essentially 90°, in some cases preventing its use. This paper proposes a novel algorithm to calculate the initial phase difference between two sinusoidal signals and to compensate the initial phase difference to exactly 90°. Several mathematical steps including equations are taken for the compensation. The mathematical equations are successfully simulated by using a numerical method to verify their availability in a computer simulation. In addition, experimental verification is also shown to confirm the performance of the algorithm by using a function generator and a data acquisition system. Finally, the phase measurement is also successfully performed by using the phase-compensating algorithm and the error of the phase measurement is analyzed.

Kim, Dae-Hyun; Ahn, Byung-Jun

2013-10-01

62

Atmospheric Correction Algorithm for Hyperspectral Remote Sensing of Ocean Color from Space  

Microsoft Academic Search

Existing atmospheric correction algorithms for multichannel remote sensing of ocean color from space were designed for retrieving water-leaving radiances in the visible over clear deep ocean areas and cannot easily be modified for retrievals over turbid coastal waters. We have developed an atmospheric correc- tion algorithm for hyperspectral remote sensing of ocean color with the near-future Coastal Ocean Imaging Spectrometer.

Bo-Cai Gao; Marcos J. Montes; Ziauddin Ahmad; Curtiss O. Davis

2000-01-01

63

Dynamic compensation for infrared thermometer based on Wiener model and particle swarm optimization algorithm  

Microsoft Academic Search

A novel structure of dynamic model is proposed in this paper and applied to construct a dynamic model to correct the dynamic errors of the infrared thermometer, because of which the dynamic performance of the thermometer is effectively improved. The dynamic compensator is established and the compensation is described and explicated by the Wiener model. According to Wiener model, the

Wen Jie Tian; Yue Tian; Lan Ai; Ji Cheng Liu

2009-01-01

64

Acceleration of motion-compensated PET reconstruction: ordered subsets-gates EM algorithms and a priori reference gate information.  

PubMed

Patient motion during positron emission tomography scans leads to significant resolution loss and image degradation. Motion-compensated image reconstruction (MCIR) algorithms have proven to be reliable correction methods given accurate deformation fields. However, although ordered subsets (OS) are widely used to speed up the convergence, OS-MCIR algorithms are still computationally expensive. This study concentrates on acceleration of OS-MCIR algorithms through two methods: combining OS with motion subsets and use of an initial estimate based on reference gate data. These approaches were compared to two existing OS-MCIR algorithms and post-reconstruction registration using data from the NCAT phantom. The methods were evaluated in terms of noise, lesion bias and contrast-to-noise ratio (CNR). The straightforward combination of motion subsets with projection subsets (OSGEM) produced inferior results (lower CNR, p < 0.01) to existing OS-MCIR algorithms. The addition of a spacer step using data from all gates to OSGEM resulted in an algorithm (SS-OSGEM) that generated images that were statistically consistent with those from existing OS-MCIR algorithms (no significant difference in CNR, p > 0.05) at one third of the computational expense. The use of a reference gate initial estimate (MCDOi) resulted in comparable image quality in terms of bias and CNR (p > 0.05) at half the computational burden. This study indicates that MCDOi and SS-OSGEM in particular are attractive accelerated OS-MCIR approaches. PMID:21346272

Dikaios, N; Fryer, T D

2011-02-23

65

Acceleration of motion-compensated PET reconstruction: ordered subsets-gates EM algorithms and a priori reference gate information  

NASA Astrophysics Data System (ADS)

Patient motion during positron emission tomography scans leads to significant resolution loss and image degradation. Motion-compensated image reconstruction (MCIR) algorithms have proven to be reliable correction methods given accurate deformation fields. However, although ordered subsets (OS) are widely used to speed up the convergence, OS-MCIR algorithms are still computationally expensive. This study concentrates on acceleration of OS-MCIR algorithms through two methods: combining OS with motion subsets and use of an initial estimate based on reference gate data. These approaches were compared to two existing OS-MCIR algorithms and post-reconstruction registration using data from the NCAT phantom. The methods were evaluated in terms of noise, lesion bias and contrast-to-noise ratio (CNR). The straightforward combination of motion subsets with projection subsets (OSGEM) produced inferior results (lower CNR, p < 0.01) to existing OS-MCIR algorithms. The addition of a spacer step using data from all gates to OSGEM resulted in an algorithm (SS-OSGEM) that generated images that were statistically consistent with those from existing OS-MCIR algorithms (no significant difference in CNR, p > 0.05) at one third of the computational expense. The use of a reference gate initial estimate (MCDOi) resulted in comparable image quality in terms of bias and CNR (p > 0.05) at half the computational burden. This study indicates that MCDOi and SS-OSGEM in particular are attractive accelerated OS-MCIR approaches.

Dikaios, N.; Fryer, T. D.

2011-03-01

66

A fast compensation algorithm for real-time control of magnetostrictive actuators  

NASA Astrophysics Data System (ADS)

Applications of magnetostrictive materials in smart devices spread from micro-positioning to active compensation of mechanical vibrations. In non-static conditions, several dynamic phenomena affects the transducer's behavior. Therefore, the design of the control system requires accurate modelling of either the static magneto-elastic constitutive relationship and rate-dependent behavior. Also when dynamic effects are not negligible, compensation of rate-independent (hysteresis) phenomena plays a key role when real-time control task are of concern. In the paper a new approach to hysteresis compensation is described. The basic properties, either in terms of accuracy and computational efficiency, are analyzed and compared to other approaches.

Davino, D.; Natale, C.; Pirozzi, S.; Visone, C.

2005-04-01

67

Algorithm for automatic atmospheric corrections to visible and near-IR satellite imagery  

Microsoft Academic Search

An algorithm is developed for automatic atmospheric correction of satellite imagery of the Earth's surface. The algorithm is based solely on the satellite image being corrected and on climatology of the area. It is applicable to low resolution (1 km field of view) and high resolution (10-80m field of view) imagery of land areas for the solar spectrum. The algorithm

Yoram J. Kaufman; Claudia Sendra

1988-01-01

68

Precision laser surveying instrument using atmospheric turbulence compensation by determining the absolute displacement between two laser beam components  

DOEpatents

Atmospheric effects on sighting measurements are compensated for by adjusting any sighting measurements using a correction factor that does not depend on atmospheric state conditions such as temperature, pressure, density or turbulence. The correction factor is accurately determined using a precisely measured physical separation between two color components of a light beam (or beams) that has been generated using either a two-color laser or two lasers that project different colored beams. The physical separation is precisely measured by fixing the position of a short beam pulse and measuring the physical separation between the two fixed-in-position components of the beam. This precisely measured physical separation is then used in a relationship that includes the indexes of refraction for each of the two colors of the laser beam in the atmosphere through which the beam is projected, thereby to determine the absolute displacement of one wavelength component of the laser beam from a straight line of sight for that projected component of the beam. This absolute displacement is useful to correct optical measurements, such as those developed in surveying measurements that are made in a test area that includes the same dispersion effects of the atmosphere on the optical measurements. The means and method of the invention are suitable for use with either single-ended systems or a double-ended systems.

Veligdan, James T. (Manorville, NY)

1993-01-01

69

An analytical image reconstruction algorithm to compensate for scattering angle broadening in Compton cameras.  

PubMed

Compton cameras have been developed for use in gamma-ray astronomy and nuclear medicine. Their defining merit is that they do not need collimators; however, on the demerit side, they need inversion procedures for image reconstruction, since a measured datum is proportional to the integration of incident gamma rays along a cone surface with the same Compton scattering angle. First, an iteration method was adopted for this task. Later, analytical methods were found under restricted conditions. Parra (2000 IEEE Trans. Nucl. Sci. 47 1543-50) deduced a purely analytical reconstruction algorithm for a complete set of scattering-projection data that include data at all the scattering angles. Tomitani and Hirasawa (2002 Phys. Med. Biol. 47 2129-45) found that by making a slight modification, Parra's algorithm could be extended to the scattering-projection data in limited scattering angles. However, their algorithm neglected the effects of practical problems that cause the degradation of spatial resolution. Sources of degradation were identified as noise in the energy signal of their front detector and the Doppler effect in the scattering process. In this paper, we first analyse the effects of these sources on the angular resolution of the scattering-projection data and then present a revised reconstruction algorithm in which these two factors are incorporated. Simulation studies on digital phantoms reveal that the algorithm can reconstruct images even when these two factors are included. PMID:12741498

Hirasawa, M; Tomitani, T

2003-04-21

70

Study on compensation algorithm of head skew in hard disk drives  

NASA Astrophysics Data System (ADS)

In hard disk drives (HDDs), head skew among multiple heads is pre-calibrated during manufacturing process. In real applications with high capacity of storage, the head stack may be tilted due to environmental change, resulting in additional head skew errors from outer diameter (OD) to inner diameter (ID). In case these errors are below the preset threshold for power on recalibration, the current strategy may not be aware, and drive performance under severe environment will be degraded. In this paper, in-the-field compensation of small DC head skew variation across stroke is proposed, where a zone table has been equipped. Test results demonstrating its effectiveness to reduce observer error and to enhance drive performance via accurate prediction of DC head skew are provided.

Xiao, Yong; Ge, Xiaoyu; Sun, Jingna; Wang, Xiaoyan

2011-10-01

71

Algorithms for locating faults on series compensated lines using neural network and deterministic methods  

SciTech Connect

This paper investigates a scheme to improve the reach measurement of distance relays and fault locators for series compensated lines. A deterministic method and a feedforward neural network method have been implemented for on-line calculation of the voltage across a non-linear capacitor installation. These techniques are compared and incorporated into a new relaying scheme which is independent of the series capacitor installation, operation of the capacitor protection, and the surrounding power system elements. The proposed scheme is simple and accurate and requires only local voltage and current at the bus. Detailed testing using EMTP has been done to show the benefits of the new adaptive scheme. The results demonstrate the suitability of the techniques for real world applications.

Novosel, D.; Bachmann, B.; Hart, D.; Hu, Y.; Saha, M.M.

1996-10-01

72

Birefringence dispersion compensation demodulation algorithm for polarized low-coherence interferometry.  

PubMed

A demodulation algorithm based on the birefringence dispersion characteristics for a polarized low-coherence interferometer is proposed. With the birefringence dispersion parameter taken into account, the mathematical model of the polarized low-coherence interference fringes is established and used to extract phase shift information between the measured coherence envelope center and the zero-order fringe, which eliminates the interferometric 2? ambiguity of locating the zero-order fringe. A pressure measurement experiment using an optical fiber Fabry-Perot pressure sensor was carried out to verify the effectiveness of the proposed algorithm. The experiment result showed that the demodulation precision was 0.077 kPa in the range of 210 kPa, which was improved by 23 times compared to the traditional envelope detection method. PMID:24104678

Wang, Shuang; Liu, Tiegen; Jiang, Junfeng; Liu, Kun; Yin, Jinde; Wu, Fan

2013-08-15

73

Fast full-search block-matching algorithm for motion-compensated video compression  

Microsoft Academic Search

This paper proposes a fast block-matching algorithm that uses three fast matching error measures, besides the conventional mean-absolute error (MAE) or mean-square error (MSE). An incoming reference block in the current frame is compared to candidate blocks within the search window using multiple matching criteria. These three fast matching error measures are established on the integral projections, having the advantages

Yih-Chuan Lin; Shen-Chuan Tai

1997-01-01

74

Ion beam figuring of high-slope surfaces based on figure error compensation algorithm.  

PubMed

In a deterministic figuring process, it is critical to guarantee high stability of the removal function as well as the accuracy of the dwell time solution, which directly influence the convergence of the figuring process. Hence, when figuring steep optics, the ion beam is required to keep a perpendicular incidence, and a five-axis figuring machine is typically utilized. In this paper, however, a method for high-precision figuring of high-slope optics is proposed with a linear three-axis machine, allowing for inclined beam incidence. First, the changing rule of the removal function and the normal removal rate with the incidence angle is analyzed according to the removal characteristics of ion beam figuring (IBF). Then, we propose to reduce the influence of varying removal function and projection distortion on the dwell time solution by means of figure error compensation. Consequently, the incident ion beam is allowed to keep parallel to the optical axis. Simulations and experiments are given to verify the removal analysis. Finally, a figuring experiment is conducted on a linear three-axis IBF machine, which proves the validity of the method for high-slope surfaces. It takes two iterations and about 9 min to successfully figure a fused silica sample, whose aperture is 21.3 mm and radius of curvature is 16 mm. The root-mean-square figure error of the convex surface is reduced from 13.13 to 5.86 nm. PMID:21124541

Dai, Yifan; Liao, Wenlin; Zhou, Lin; Chen, Shanyong; Xie, Xuhui

2010-12-01

75

Atmospheric correction algorithm based on vector radiative transfer modeling for hyperspectral remote sensing of ocean color  

NASA Astrophysics Data System (ADS)

Multi-channel remote sensing of ocean color from space has a rich history -- from the past CZCS, to the present SeaWiFS, and to the near-future MODIS. The atmospheric correction algorithms for processing remotely sensed data from these sensors were mainly developed by Howard Gordon at University of Miami. The algorithms were primarily designed for retrieving water leaving radiances in the visible spectral region over clear deep ocean areas. The information about atmospheric aerosols is derived from channels between 0.66 and 0.87 micrometer, where the water leaving radiances are close to zero. The derived aerosol information is extrapolated back to the visible when retrieving water leaving radiances from remotely sensed data. For the turbid coastal environment, the water leaving radiances for channels between 0.66 and 0.87 micrometer may not be close to zero because of back scattering by suspended materials in the water. Under these conditions, the channels are no longer useful for deriving information on atmospheric aerosols. As a result, the algorithms developed for applications to clear ocean waters cannot be easily modified to retrieve water leaving radiances from remote sensing data acquired over the costal environments. We have recently developed a fast and fully functional atmospheric correction algorithm for hyperspectral remote sensing of ocean color with the Coastal Ocean Imaging Spectrometer (COIS). Our algorithm uses lookup tables generated with a vector radiative transfer code developed by Ahmad and Fraser (1982) and a spectral matching technique for the retrieval of water leaving radiances. The information on atmospheric aerosols is estimated using dark channels beyond 0.86 micron. Quite reasonable results were obtained when applying the algorithm to process spectral imaging data acquired over Chesapeake Bay with the NASA JPL Airborne Visible Infrared Imaging Spectrometer (AVIRIS).

Gao, BoCai; Montes, Marcos J.; Ahmad, Ziauddin; Davis, Curtiss O.

1999-10-01

76

Restoration of atmospheric turbulence degraded video using kurtosis minimization and motion compensation  

NASA Astrophysics Data System (ADS)

It has been long recognized that atmospheric turbulence degrades the quality of images and video sequences. Stationary objects being observed through the atmosphere can appear blurred and waver spatially as if they are in motion. This phe- nomenon is well recognized, especially in astronomy. The degradation arises from the complicated, random fluctuations in the refractive index of the air, caused by fluctuations in temperature. In this thesis, the fundamental theory of turbulence such as the Kolmogorov law is reviewed. It is also shown that the point spread function (PSF) of the turbulence can be derived from the physics equations that describe atmospheric turbulence. Atmospheric turbulence degradation is usually modeled as a linear convolution. The turbulence is dynamic and random in nature. The blurring parameter of the PSF of the turbulence is dependent on altitude, temperature, the rate of energy per mass dissipated by viscous friction, the sheer rate of the wind, and soon. Information about those turbulence conditions is often not available. Thus, the exact PSF of the turbulence blur is generally unknown in practice. Consequentially, blind image deconvolution technique is used in such a context. Blind image deconvolution is well known to be an ill-posed problem. Certain assumptions about the image and/or the blur must be made in order to find a solution. It has been observed that the kurtosis of the blurred (smoothed) image is often higher than an unblurred version. This observation is studied and justified using a frequency domain analysis where kurtosis is first represented and then interpreted. An image can be decomposed into a low frequency component and a high frequency component. It is found that the kurtosis of an image is dominated by the interaction of the low frequency and high frequency components. Blurring alters the interaction and tends to increase the kurtosis. In addition to the theoretical analysis, experiments are conducted to verify that the smoothed image has higher kurtosis. This important observation forms the basis for the new blind deconvolution method. Kurtosis can be viewed as a metric to measure the quality of the resorted image without having the original image. In simulations, when an original image is available, one can use peak signal-to-noise ratio (PSNR), to determine the restored image that has the highest PSNR (PSNR maximization) to estimate the blurring parameter. Kurtosis minimization based blur identification works as following given the functional form of the blur and an estimate of the parameter space, the parameter is searched by minimizing the kurtosis of the restored image. The restored image that has minimal kurtosis is used as the final estimate of the true image and the corresponding parameter is the identified blurring parameter. In many simulations, kurtosis minimization gives the same result as PSNR maximization. Kurtosis minimization is a generally applicable blur identification method. It has been tested on a variety of blurs including Gaussian blur, linear motion blur, out-of-focus blur, averaging blur and atmospheric turbulence blurs. In many experiments on standard test images, kurtosis minimization is able to give perfect estimation at different levels of noise. Moreover, it is compared with generalized cross validation (GCV) based blur identification on atmospheric turbulence blurs, which is the main application in this thesis work. Besides blurring, turbulence also introduces geometric distortion in the video since the turbulence is time-varying. (Abstract shortened by UMI.)

Li, Dalong

2007-08-01

77

An operational atmospheric correction algorithm for Landsat Thematic Mapper imagery over the land  

Microsoft Academic Search

An operational atmospheric correction algorithm for Thematic Mapper (TM) imagery has been developed for both sequential and parallel computer environments considering both aerosol and molecular scattering and absorption. The aerosol optical depth is estimated from the image itself using the dark object approach on a moving-window basis, and the surface reflectance is then retrieved by searching lookup tables that are

Shunlin Liang; Hassan Fallah-Adl; Satya Kalluri; Joseph JáJá; Yoram J. Kaufman; John R. G. Townshend

1997-01-01

78

Brightness-compensated 3-D optical flow algorithm for monitoring cochlear motion patterns  

NASA Astrophysics Data System (ADS)

A method for three-dimensional motion analysis designed for live cell imaging by fluorescence confocal microscopy is described. The approach is based on optical flow computation and takes into account brightness variations in the image scene that are not due to motion, such as photobleaching or fluorescence variations that may reflect changes in cellular physiology. The 3-D optical flow algorithm allowed almost perfect motion estimation on noise-free artificial sequences, and performed with a relative error of <10% on noisy images typical of real experiments. The method was applied to a series of 3-D confocal image stacks from an in vitro preparation of the guinea pig cochlea. The complex motions caused by slow pressure changes in the cochlear compartments were quantified. At the surface of the hearing organ, the largest motion component was the transverse one (normal to the surface), but significant radial and longitudinal displacements were also present. The outer hair cell displayed larger radial motion at their basolateral membrane than at their apical surface. These movements reflect mechanical interactions between different cellular structures, which may be important for communicating sound-evoked vibrations to the sensory cells. A better understanding of these interactions is important for testing realistic models of cochlear mechanics.

von Tiedemann, Miriam; Fridberger, Anders; Ulfendahl, Mats; de Monvel, Jacques Boutet

2010-09-01

79

Enhanced functional brain imaging by using adaptive filtering and a depth compensation algorithm in diffuse optical tomography.  

PubMed

Reflectance diffuse optical tomography (rDOT) of brain function is limited by its high sensitivity to the superficial tissues (i.e., the scalp and skull) and by its severe decrease in measurement sensitivity with increased depth. Significant interference in rDOT results from spontaneous fluctuations that are embedded in both the superficial tissues and brain, such as arterial pulsation and vasomotion. In this study, first we investigate coherence and phase shift of the spontaneous fluctuations in the resting state, within the superficial tissues and at various depths of the brain, respectively. We demonstrate that the spontaneous fluctuations originating from arterial pulsations ( ? 1 Hz) are spatially global and temporally coherent, while the fluctuations originating from vasomotion ( ? 0.1 Hz) tend to have less coherence with increased depth. Second, adaptive cancellation of spontaneous fluctuations with a frequency-specific strategy is utilized and validated in both resting and activation (evoked by a finger-tapping task) states. Third, improved depth localization of motor activation in reconstructed rDOT images is achieved by combining adaptive cancellation with a depth compensation algorithm that we recently reported. PMID:21296704

Tian, Fenghua; Niu, Haijing; Khan, Bilal; Alexandrakis, George; Behbehani, Khosrow; Liu, Hanli

2011-02-04

80

High-resolution studies of the structure of the solar atmosphere using a new imaging algorithm  

NASA Astrophysics Data System (ADS)

The results of the application of a new image restoration algorithm developed by Ayers and Dainty (1988) to the multiwavelength EUV/Skylab observations of the solar atmosphere are presented. The application of the algorithm makes it possible to reach a resolution better than 5 arcsec, and thus study the structure of the quiet sun on that spatial scale. The results show evidence for discrete looplike structures in the network boundary, 5-10 arcsec in size, at temperatures of 100,000 K.

Karovska, Margarita; Habbal, Shadia Rifai

1991-04-01

81

Algorithms for radiative intensity calculations in moderately thick atmospheres using a truncation approximation  

NASA Astrophysics Data System (ADS)

The efficiency of numerical calculations is discussed for selected algorithms employing the discrete ordinate method and the truncation approximation for the solar radiative intensity in moderately thick, plane-parallel scattering atmospheres. It is found that truncation of the phase function causes a significant error in the computed intensity and the magnitude of this error depends significantly on how the intensity is retrieved from the truncated radiative transfer equation. A newly developed retrieval algorithm, the IMS-method, yields the intensity field with an error less than about 1 percent when the number of discrete paths is as small as 10 in the hemisphere for aerosol-laden atmospheres with optical thickness less than about 1.

Nakajima, T.; Tanaka, M.

1988-07-01

82

A snow/atmosphere physical parameter algorithm for the GCOM-C1/SGLI sensor  

NASA Astrophysics Data System (ADS)

The Global Change Observation Mission-Climate/Second-generation Global Imager (GCOM-C1/SGLI) is scheduled to be launched in 2014. The SGLI instrument has two major new features: 250 m spatial resolution and polarization/multidirectional observation capabilities. The 250 m resolution provides enhanced observation capability over snow/ice/mountain areas which are difficult to access. The multidirectional observations with polarization channels have the potential to do accurate snow/atmosphere retrievals, which will help improve climate prediction models. The algorithm has been constructed for the GCOM-C1/SGLI. It is designed for retrievals of snow/atmosphere parameters including aerosol optical depth, mass concentration of snow impurity, top and bottom layer snow grain size over the snow surface. To retrieve accurate physical parameters from the satellite data, we developed a new retrieval algorithm. An atmosphere-snow radiative transfer model is used as a forward model which simulates the spectral radiances for visible and near-infrared channels. The forward radiative transfer calculation is the most time-consuming part of the forward-inverse modeling because it has to be called repeatedly during the iterative inversion process. Therefore, we replaced the forward radiative transfer model with a neural network function for fast computation of radiances and Jacobians. The retrieval scheme is based on the Levenberg-Marquardt optimal estimation method instead of a traditional look-up table approach to improve the retrieval accuracy and speed. For validation of our proposed algorithm, we applied it to data obtained with the Terra/MODIS and GCOM/GLI sensors, which have channels at 443, 865 and 1640 nm similar to those of the GCOM-C1/SGLI that can be used for snow/atmosphere remote sensing. We will explore the potential for retrieving information about snow parameters as well as aerosol type and loading from the polarized radiance measurements provided by the SGLI sensor.

Tanikawa, T.; Chen, N.; Fan, Y.; Li, W.; Stamnes, K. H.

2010-12-01

83

A time series algorithm for simultaneous retrieval of atmospheric aerosol and surface reflectance from MODIS  

NASA Astrophysics Data System (ADS)

If given a consecutive set of images of the same region of the Earth obtained from space, an untrained human will easily solve many of the remote sensing problems, such as selecting clear-skies areas, identifying clouds, distinguishing between clear and hazy conditions, and so on. What, in contrast to our brain's work, is missing in our algorithms, armed with the modern science, that solving these problems becomes difficult and fraught with uncertainties? One answer is that the contemporary concepts of aerosol and land remote sensing from whiskbroom (MODIS-like) sensors are pixel-based and disregard history of previous measurements. In this case, some important invariants of the atmosphere-surface system are overlooked. One example is a spatial structure (or texture) of the land surface at the landscape level, which generally changes at a very slow rate as compared to the frequency of spaceborne observations. A new Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm developed for MODIS will be described, which uses multi-temporal observations and an image-based rather than pixel-based processing. MAIAC retrieves aerosol optical thickness simultaneously with surface bidirectional reflectance and albedo at a spatial resolution of 1 km. The algorithm is generic and works over the dark vegetated surfaces as well as over bright deserts. An extensive validation shows a good agreement of retrievals with AERONET measurements.

Lyapustin, A.; Wang, Y.

2009-04-01

84

Global Soundings of the Atmosphere from ATOVS Measurements: The Algorithm and Validation.  

NASA Astrophysics Data System (ADS)

The International Advanced Television and Infrared Observation Satellite Operational Vertical Sounder (ATOVS) Processing Package (IAPP) has been developed to retrieve the atmospheric temperature profile, moisture profile, atmospheric total ozone, and other parameters in both clear and cloudy atmospheres from the ATOVS measurements. The algorithm that retrieves these parameters contains four steps: 1) cloud detection and removal, 2) bias adjustment for ATOVS measurements, 3) regression retrieval processes, and 4) a nonlinear iterative physical retrieval. Nine (3 × 3) adjacent High-Resolution Infrared Sounder (HIRS)/3 spot observations, together with Advanced Microwave Sounding Unit-A observations remapped to the HIRS/3 resolution, are used to retrieve the temperature profile, moisture profile, surface skin temperature, total atmospheric ozone and microwave surface emissivity, and so on. ATOVS profile retrieval results are evaluated by root-mean-square differences with respect to radiosonde observation profiles. The accuracy of the retrieval is about 2.0 K for the temperature at 1-km vertical resolution and 3.0-6.0 K for the dewpoint temperature at 2-km vertical resolution in this study. The IAPP is now available to users worldwide for processing the real-time ATOVS data.

Li, Jun; Wolf, Walter W.; Menzel, W. Paul; Zhang, Wenjian; Huang, Hung-Lung; Achtor, Thomas H.

2000-08-01

85

PMD compensation in multilevel coded-modulation schemes with coherent detection using BLAST algorithm and iterative polarization cancellation.  

PubMed

We present two PMD compensation schemes suitable for use in multilevel (M>or=2) block-coded modulation schemes with coherent detection. The first scheme is based on a BLAST-type polarization-interference cancellation scheme, and the second scheme is based on iterative polarization cancellation. Both schemes use the LDPC codes as channel codes. The proposed PMD compensations schemes are evaluated by employing coded-OFDM and coherent detection. When used in combination with girth-10 LDPC codes those schemes outperform polarization-time coding based OFDM by 1 dB at BER of 10(-9), and provide two times higher spectral efficiency. The proposed schemes perform comparable and are able to compensate even 1200 ps of differential group delay with negligible penalty. PMID:18795021

Djordjevic, Ivan B; Xu, Lei; Wang, Ting

2008-09-15

86

A novel fair queuing algorithm for hybrid wired/wireless architecture with wireless compensation to provide end-to-end quality of service support  

NASA Astrophysics Data System (ADS)

We proposed novel hybrid FSO/RF architecture1 to provide broadband wireless access to end users. To provide quality of service (QoS) bounds for different types of traffic(voice, video and data) we proposed some fair queuing algorithms2,3 ,but because of the hybrid wired and wireless links there can be certain times allocated to a host when that host is unable to transmit data because of wireless link errors. These wireless link errors are location dependent and bursty. The channel errors can occur from multi-path fading, shadow fading or interference from another device. In this paper we proposed a novel fair queuing algorithm to provide end to end QoS bounds to the end users for the proposed architecture .The algorithm provide QoS bounds for Ethernet traffic in the wired domain as well as in wireless domain with compensation for wireless link errors. Scheduler maps priorities and weights for QoS of the Ethernet traffic into wireless MAC. By supporting existing Ethernet traffic QoS parameters 4-7, scheduler avoids the need to redefine QoS parameters for wireless channel. By simulations and analysis we proved that the algorithm guarantees (1) delay and throughput for error-free flows, (2) short term fairness among error-free flows, (3) long term fairness among errored and error-free flows,(4) graceful degradation for leading flows and graceful compensation for lagging flows. Each connection QoS is guaranteed by calculating bounds on delay and reserving the Bandwidth (BW).

Sana, Ajaz; Ye, Xin; Hussain, Shahab; Ali, Mohammed A.; Ahmed, Samir

2007-09-01

87

New error-compensating seven-sample phase-shifting algorithm and application in 3D fringe projection profilometry  

NASA Astrophysics Data System (ADS)

In this paper, a new 7-sample algorithm is derived based on the Surrel 6-sample algorithm by using the averaging technique. The Surrel 6-sample algorithm and the new 7- sample algorithm are analyzed using the Fourier description method and it is shown that the new 7-sample is more insensitive to linear phase-shift miscalibration than the Surrel 6-sample algorithm. By computer simulation, it is found that the linear phase-shift miscalibration produces the periodic phase error at three times the fringe frequency when the fringe signal contains a second-harmonic component. P-V phase error plots show that the new 7-sample algorithm is the least sensitive to the linear phase-shift miscalibration of the five phase-shifting algorithms considered in this paper when the fringe signal contains the second-harmonic component. A 3D fringe projection phase- shifting profilometry is constructed using a white light source and projecting a quasi-sinusoidal grating. The fringe pattern is captured by a CCD camera connected to a frame grabber in a PC computer. The new 7-sample algorithm is used and the experimental results are presented.

Zhang, Hong; Lalor, Michael J.; Burton, David R.

1998-06-01

88

Sensitivity of a lidar inversion algorithm to parameters relating atmospheric backscatter and extinction  

NASA Astrophysics Data System (ADS)

A solution of the single-scattering lidar equation requires a relationship between the coefficients of backscatter beta (r) and extinction sigma(r) to be of the form beta(r) = C(2) Sigma (r) Exp k, where C2 and k are parameters independent of range r. The sensitivity of a particular lidar inversion algorithm to uncertainties in C(2) and k is investigated using a measured lidar return which indicated the atmosphere to be essentially horizontally homogeneous during a reduced visibility condition. Starting with the measured power returned as a function of range, extinction coefficients and average visibilities are calculated using the inversion algorithm for different values of C(2) and k and compared with those inferred from the lidar return using the slope method. The calculated extinction coefficients (and visibilities) were found to be extremely sensitive to uncertainties in C(2). This questions the usefulness of the lidar inversion algorithm for aerosol extinction applications when the air mass characteristics change along the measurement path.

Hughes, H. G.; Ferguson, J. A.; Stephens, D. H.

1985-06-01

89

Simulation of atmospheric turbulence for a qualitative evaluation of image restoration algorithms with motion detection  

NASA Astrophysics Data System (ADS)

Remote sensing applications are generally concerned with observing objects over long distances. When imaging over long horizontal paths, image resolution is limited by the atmosphere rather than by the design and quality of the optical system being used. Atmospheric turbulence can cause quite severe image degradation, the foremost effects being blurring and image motion. Recently, interest in image processing solutions has been rising, not least of all because of the comparatively low cost of computational power, and also due to an increasing number of imaging applications that require the correction of extended objects rather than point-like sources only. At present, the majority of these image processing methods aim exclusively at the restoration of static scenes. But there is a growing interest in enhancing turbulence mitigation methods to include moving objects as well. However, an unbiased qualitative evaluation of the respective restoration results proves difficult if little or no additional information on the "true image" is available. Therefore, in this paper synthetic ground truth data containing moving vehicles were generated and a first-order atmospheric propagation simulation was implemented in order to test such algorithms. The simulation employs only one phase screen and assumes isoplanatic conditions (only global image motion) while scintillation effects are ignored.

Huebner, Claudia S.; Gladysz, Szymon

2012-10-01

90

A coupled oceanic and atmospheric spectral optimization algorithm for application to ocean color satellites: sensitivity to near-infrared error  

NASA Astrophysics Data System (ADS)

A spectral optimization algorithm (SOA) has been developed for processing satellite data in marine waters. The algorithm couples an atmospheric aerosol model with a detailed water-reflectance model to simultaneously retrieve both atmospheric and ocean color parameters. A key feature separating SOA from standard algorithms is the retrieval of the absorption coefficient of colored detrital material, particulate backscattering and chlorophyll concentration in absorbing atmospheres. The same parameters can also be retrieved in Case 2 waters where higher particulate backscattering contributes to the near-infrared (NIR) water-leaving reflectance. Results of chlorophyll concentration are presented in this study using SeaWiFS data obtained for the Chesapeake Bay and Middle Atlantic Bight. Manipulations to the NIR measurements of a degree similar to the magnitude of sensor noise and calibration uncertainty show that the chlorophyll retrievals are highly sensitive to the error in the measured NIR total reflectance.

Kuchinke, Christopher P.; Gordon, Howard R.; Voss, Kenneth J.

2005-01-01

91

An atmospheric correction algorithm for remote identification of non-Lambertian surfaces and its range of validity  

SciTech Connect

The usefulness of remotely sensed surface data depends on the ability to correct for atmospheric pertubations on the image. An atmospheric correction algorithm has been proposed which removes atmospheric pertubations from off-nadir measured radiances at the top of the atmosphere in the visible and near-infrared wavelength region. The ability of the model to reproduce radiance distributions at the surface from radiances at the top of the atmosphere is tested and found to be better than 15%. The correction formalism requires as minimum information the total optical depth of the atmosphere and the surface albedo. In this study the accuracy of the model to assumptions about the aerosol phase function, the single-scattering albedo and the vertical profile of the optical depth is also tested.

Gratzki, A.; Gerstl, S.A.W.

1987-02-20

92

Atmospheric correction for ocean colour images using a classification and a neuro-variational algorithm  

NASA Astrophysics Data System (ADS)

Radiometers on board satellite measure the solar radiation reflected by both ocean and atmosphere at several wavelengths. One difficulty is that the signal is strongly polluted by the contribution of the atmosphere. An important step in the processing of ocean colour images is the so-called "atmospheric correction" that consists in removing the contribution of the atmospheric signal to solely retrieve the ocean contribution. Due to the presence of aerosols in the atmosphere, this contribution cannot be predicted a priori. Thus, standard algorithms use a part of the signal, generally the near-infrared bands, to deduce the contribution of aerosols to the signal. It is necessary to make some assumptions on the contribution of the ocean for these bands. Most of the time this contribution is determined a priori. In some situations, this approach is not relevant. Two main problems can occur: (1) The ocean contribution can not be determined a priori in the near-infrared bands; it is the case of most of the coastal waters where the content of the water is complex and not be predicted. (2) The near-infrared part of the signal is not enough to entirely deduce the aerosol contribution; it is the case of absorbing aerosol. To solve this problem, a methodology was proposed: NeuroVaria. It was based on the spectral matching principle: instead of making strong hypothesis on the oceanic contribution, a multispectral optimization is made on both oceanic and atmospheric signal. NeuroVaria alone was already validated in several cases. To improve the accuracy of the results and to process more situations, NeuroVaria was combined with a classification procedure in order to constrain the inversion. The classification was done with neuronal classifier (SOM map). The method was applied to the daily MODIS images off the Senegal coast. The resulting oceanic products were validated and a data archive of the daily MODIS data of the region is under construction. This database comprises the Chla-a concentration, the water leaving reflectance spectrum, the aerosol parameters.

Brajard, Julien; Diouf, Daouda; Crépon, Michel; Thiria, Sylvie

2013-04-01

93

Correction of atmospheric effect on ADEOS\\/OCTS ocean color data: Algorithm description and evaluation of its performance  

Microsoft Academic Search

This paper first describes the atmospheric correction algorithm for OCTS visible band data used at NASDA\\/EOC. Sharing a basic\\u000a structure with Gordon and Wang’s Sea WiFS algorithm, it uses 10 candidate aerosol models including the “Asian dust model”\\u000a introduced in consideration of the unique feature of aerosols over the east Asian waters. Based on the observations at 670\\u000a and 865

Hajime Fukushima; Akiko Higurashi; Yasushi Mitomi; Teruyuki Nakajima; Toshimitsu Noguchi; Toshio Tanaka; Mitsuhiro Toratani

1998-01-01

94

Simulation of atmospheric turbulence effects and mitigation algorithms on stand-off automatic facial recognition  

NASA Astrophysics Data System (ADS)

Stand-off base and force protection surveillance measures primarily rely on electro-optic and thermal imaging technology. Atmospheric turbulence causes blur, distortion and intensity fluctuations that can severely degrade the image quality of these systems. This work explores the effects of turbulence image degradation on the performance of automatic facial recognition software and also looks at the potential benefit of turbulence mitigation algorithms. The goal of this work is to understand the feasibility of long-range facial recognition in degraded imaging conditions. In order to create a large enough database to match against, simulated imagery of different ranges and turbulence conditions were created using a horizontal view turbulence simulator and a subset of the Facial Recognition Technology (FERET) database. The simulated turbulence degraded imagery was then processed with facial recognition software and the results are compared against those from the pristine image set. Finally, the performance of the facial recognition software with turbulence mitigated imagery is also presented.

Leonard, Kevin R.; Howe, Jonathan; Oxford, David E.

2012-10-01

95

Ground based measurements on reflectance towards validating atmospheric correction algorithms on IRS-P6 AWiFS data  

NASA Astrophysics Data System (ADS)

In Earth observation, the atmosphere has a non-negligible influence on the visible and infrared radiation which is strong enough to modify the reflected electromagnetic signal and at-target reflectance. Scattering of solar irradiance by atmospheric molecules and aerosol generates path radiance, which increases the apparent surface reflectance over dark surfaces while absorption by aerosols and other molecules in the atmosphere causes loss of brightness to the scene, as recorded by the satellite sensor. In order to derive precise surface reflectance from satellite image data, it is indispensable to apply the atmospheric correction which serves to remove the effects of molecular and aerosol scattering. In the present study, we have implemented a fast atmospheric correction algorithm to IRS-P6 AWiFS satellite data which can effectively retrieve surface reflectance under different atmospheric and surface conditions. The algorithm is based on MODIS climatology products and simplified use of Second Simulation of Satellite Signal in Solar Spectrum (6S) radiative transfer code, which is used to generate look-up-tables (LUTs). The algorithm requires information on aerosol optical depth for correcting the satellite dataset. The proposed method is simple and easy to implement for estimating surface reflectance from the at sensor recorded signal, on a per pixel basis. The atmospheric correction algorithm has been tested for different IRS-P6 AWiFS False color composites (FCC) covering the ICRISAT Farm, Patancheru, Hyderabad, India under varying atmospheric conditions. Ground measurements of surface reflectance representing different land use/land cover, i.e., Red soil, Chick Pea crop, Groundnut crop and Pigeon Pea crop were conducted to validate the algorithm and found a very good match between surface reflectance and atmospherically corrected reflectance for all spectral bands. Further, we aggregated all datasets together and compared the retrieved AWiFS reflectance with aggregated ground measurements which showed a very good correlation of 0.96 in all four spectral bands (i.e. green, red, NIR and SWIR). In order to quantify the accuracy of the proposed method in the estimation of the surface reflectance, the root mean square error (RMSE) associated to the proposed method was evaluated. The analysis of the ground measured versus retrieved AWiFS reflectance yielded smaller RMSE values in case of all four spectral bands. EOS TERRA/AQUA MODIS derived AOD exhibited very good correlation of 0.92 and the data sets provides an effective means for carrying out atmospheric corrections in an operational way. Keywords: Atmospheric correction, 6S code, MODIS, Spectroradiometer, Sun-Photometer

Rani Sharma, Anu; Kharol, Shailesh Kumar; Kvs, Badarinath; Roy, P. S.

96

Phase compensation of SAL imaging combining Rayleigh LGS with PGA in strong turbulence  

NASA Astrophysics Data System (ADS)

High imaging resolution can be achieved by using synthetic aperture ladar (SAL) with laser radiation source. The destruction of the signal phase information caused by atmospheric turbulence makes the optical heterodyne detection efficiency reduce. Therefore the imaging performance of SAL degraded seriously. The study on the influence of atmospheric turbulence on SAL imaging is of great significance and an effective compensation method of image is necessary to be found. Research shows that conventional phase gradient autofocus (PGA) algorithm has some improvement on SAL imaging only in weak turbulence. The mixed phase compensation method combining Rayleigh laser guide star (LGS) with PGA algorithm is presented based on the real-time detection of optical wavefront phase distortion with Rayleigh LGS and the phase compensation method of the SAL images. The phase distortion caused by different turbulence intensities with von Karman spectrum is estimated with Rayleigh LGS. SAL echo signals are compensated with the estimated phase and the PGA algorithm is implemented in the final imaging data. The results show that significant improvements of the SAL images in moderate turbulence are obtained and the images can be identified basically by using the mixed phase compensation method in strong turbulence. The focusing effect of the SAL images is improved effectively, and a higher SAL resolution is gained in azimuth. In addition, the research of SAL imaging compensation in atmospheric turbulence in a slant path is carried out for the first time, which is of great significance to the practical application of SAL.

Han, Yan-yan; Lu, Fang; Han, Xiang'e.; Liu, Chun-bo

2013-09-01

97

Photonic-crystal fibers for dispersion compensation in short-pulse fiber laser sources: design algorithms and dispersion characterization  

Microsoft Academic Search

This work aims at developing a PCF-based stretcher for a sub-mJ fiber chirped pulse amplifier (FCPA) capable of correcting the higher-order dispersion of the amplifier chain and the pulse compressor. We develop a conveniently formalized algorithm for the design of PCFs and prove theoretically the possibility to engineer negative dispersion PCFs of a chosen sign of cubic and quartic phase.

A. Fernandez; Lingxiao Zhu; A.-J. Verhoef; A. Baltuska; E. E. Serebryannikov; A. M. Zheltikov; D. A. Sidorov-Biryukov; J. C. Knight

2007-01-01

98

A SAR image-formation algorithm that compensates for the spatially-variant effects of antenna motion  

SciTech Connect

A synthetic aperture radar (SAR) obtains azimuth resolution by combining data from a number of points along a specified path. Uncompensated antenna motion that deviates significantly from the desired path produces spatially-variant errors in the output image. The algorithm presented in this paper corrects many of these motion-related errors. In this respect, it is similar to time-domain convolution, but it is more computationally efficient. The algorithm uses overlapped subapertures in a three-step image-formation process: coarse-resolution azimuth processing, fine-resolution range processing, and fine-resolution azimuth processing. Range migration is corrected after the first stage, based on coarse azimuth position. Prior to the final azimuth-compression step, data coordinates, are determined to fine resolution in range and coarse resolution in azimuth. This coordinate information is combined with measured motion data to generate a phase correction that removes spatially-variant errors. The algorithm is well-suited for real-time applications, particularly where large flight-path deviations must be tolerated.

Burns, B.L.; Cordaro, J.T.

1994-03-01

99

Superresolution in compensated telescopes.  

PubMed

We present a procedure for attaining resolution beyond the diffraction limit in ground-based telescopes. This procedure is based on the use of rotationally symmetric pupil plane filters that can be easily implemented in dynamic optical devices such as a deformable mirror of an adaptive-optics system. We show that a successful application of the technique requires partial compensation for atmospheric distortion by adaptive optics. Consequently, we derive the required level of compensation as a function of the atmospheric conditions. Finally, our results are checked using simulated data. PMID:15143632

Canales, Vidal F; de Juana, Daniel M; Cagigal, Manuel P

2004-05-01

100

Water quality monitoring by thematic mapper in coastal environments. A performance analysis of local biooptical algorithms and atmospheric correction procedures  

SciTech Connect

The Thematic Mapper (TM) sensor's ability to monitor localized phenomena associated with anthropogenic pollution in coastal waters has been investigated with reference to experimental data collected on a test site in the Gulf of Naples. In situ measurements yielded the biooptical algorithms for chlorophyll and sediment retrieval as well as an optical model for the computation of the subsurface reflectance as a function of water composition, specific to the site. The algorithms' performance was assessed through a sensitivity analysis, taking into account the correlation among chlorophyll, sediment, and yellow substance contents, as well as the stratification characteristics of the water body. Sensitivity analysis techniques were similarly used to evaluate the performance in the coastal environment of three atmospheric correction models, which assume uniform aerosol load and composition, uniform aerosol composition, and varying aerosol load and composition, respectively. A comparison with sea-truth data collected for the Land-sat overpass of 22 June 1988 showed a satisfactory correspondence between measured concentrations and concentrations retrieved from the TM data using the above atmospheric correction procedures and local biooptical algorithms. Consistent with the indications of the sensitivity analysis, the best agreement was obtained by the atmospheric model assuming varying aerosol load and composition.

Tassan, S. (Commission of the European Communities, Ispra (Italy). Inst. for Remote Sensing Applications); d'Alcala, M.R. (Stazione Zoologica, Napoli (Italy). Biological Oceanography Lab.)

1993-08-01

101

Genetic algorithm applied to a Soil-Vegetation-Atmosphere system: Sensitivity and uncertainty analysis  

NASA Astrophysics Data System (ADS)

Numerical models are of precious help for predicting water fluxes in the vadose zone and more specifically in Soil-Vegetation-Atmosphere (SVA) systems. For such simulations, robust models and representative soil hydraulic parameters are required. Calibration of unsaturated hydraulic properties is known to be a difficult optimization problem due to the high non-linearity of the water flow equations. Therefore, robust methods are needed to avoid the optimization process to lead to non-optimal parameters. Evolutionary algorithms and specifically genetic algorithms (GAs) are very well suited for those complex parameter optimization problems. Additionally, GAs offer the opportunity to assess the confidence in the hydraulic parameter estimations, because of the large number of model realizations. The SVA system in this study concerns a pine stand on a heterogeneous sandy soil (podzol) in the Campine region in the north of Belgium. Throughfall and other meteorological data and water contents at different soil depths have been recorded during one year at a daily time step in two lysimeters. The water table level, which is varying between 95 and 170 cm, has been recorded with intervals of 0.5 hour. The leaf area index was measured as well at some selected time moments during the year in order to evaluate the energy which reaches the soil and to deduce the potential evaporation. Water contents at several depths have been recorded. Based on the profile description, five soil layers have been distinguished in the podzol. Two models have been used for simulating water fluxes: (i) a mechanistic model, the HYDRUS-1D model, which solves the Richards' equation, and (ii) a compartmental model, which treats the soil profile as a bucket into which water flows until its maximum capacity is reached. A global sensitivity analysis (Morris' one-at-a-time sensitivity analysis) was run previously to the calibration, in order to check the sensitivity in the chosen parameter search space. For the inversion procedure a genetical algorithm (GA) was used. Specific features such as elitism, roulette-wheel process for selection operator and island theory were implemented. Optimization was based on the water content measurements recorded at several depths. Ten scenarios have been elaborated and applied on the two lysimeters in order to investigate the impact of the conceptual model in terms of processes description (mechanistic or compartmental) and geometry (number of horizons in the profile description) on the calibration accuracy. Calibration leads to a good agreement with the measured water contents. The most critical parameters for improving the goodness of fit are the number of horizons and the type of process description. Best fit are found for a mechanistic model with 5 horizons resulting in absolute differences between observed and simulated water contents less than 0.02 cm3cm-3 in average. Parameter estimate analysis shows that layers thicknesses are poorly constrained whereas hydraulic parameters are much well defined.

Schneider, Sébastien; Jacques, Diederik; Mallants, Dirk

2010-05-01

102

Atmosphere  

NSDL National Science Digital Library

What is this atmosphere that surrounds the Earth? This instructional tutorial, part of an interactive laboratory series for grades 8-12, introduces students to the structure, effects, and components of the atmosphere. Here students investigate the composition of the atmosphere; effects of temperature, pressure, and ozone; the greenhouse effect; and how Earth compares with other planets. Interactive activities present students with opportunities to explore ideas and answer questions about the atmosphere, including its structure, the making of ozone, rocket launching, and measuring the atmosphere. Pop-up boxes provide additional information on topics such as dust, rain, and atmospheric composition. Students complete a final written review of six questions about the atmosphere. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2003-01-01

103

Wavelet-based adaptive mesh refinement algorithm for atmospheric chemical transport modeling  

Microsoft Academic Search

Numerical modeling of chemical transport in the Earth atmosphere is essential for addressing problems and issues related to atmospheric air quality, greenhouse gases budget and climate forcing. Chemical transport models (CTM) combine chemical reactions with advection by a meteorologically predicted flow velocity. The resulting system of equations is extremely stiff, nonlinear and involves a large number of chemically interacting species.

Yevgenii Rastigejev

2008-01-01

104

Combined motion compensation and reconstruction for PET  

Microsoft Academic Search

We propose a new intrinsic motion-compensation algorithm for PET called “Blind Motion Compensated Reconstruction” (BMCR). BMCR is able to deal with frames of extremely low statistics in the case of smooth motion. This is achieved by combining image reconstruction and motion compensation into one mathematical framework which consists of a cost functional and an optimization method. The cost functional basically

Moritz Blume; Magdalena Rafecas; Sibylle Ziegler; Nassir Navab

2008-01-01

105

Atmospheric Compensation Applications and Data.  

National Technical Information Service (NTIS)

Activity on this contract is divided between validation and verification testing of FLAASH and its radiative transport engine 'MODTRAN', and data collection planning and analysis needed to calibrate and validate flight hyperspectral instruments. Major eff...

J. A. Gardner A. L. Broadfoot

2004-01-01

106

Smooth motion-compensated video deinterlacing  

Microsoft Academic Search

In this paper a smooth motion-compensated ap- proach for video deinterlacing is proposed. The algorithm combines intra-field interpolation with overlapped-block-based motion- compensated inter-field interpolation, alleviating thus the artifacts specific to block-based motion-compensated deinterlac- ing schemes. Our algorithm takes into account the high-frequency content of an area and adapts the interpolation approach accordingly, such that the contours are preserved in the

Maria Trocan; Beata Mikovicova

2011-01-01

107

New lead compensator designs for control education and engineering  

Microsoft Academic Search

The lead compensator is one of the most import topics in any undergraduate control engineering courses owing to its wide industrial applications. Traditionally the lead compensator was designed in a trial and error manner. This gives rise to difficulties not only in achieving precise compensation, but also in class teaching. In this paper, a new lead compensator design algorithm is

Xu JianXin

2008-01-01

108

Compensation conundrum.  

PubMed

Pressured by questions tabled in parliament that point to a lack of adequate enforcement of regulations, the DCG(I) has abruptly initiated action to ensure payment of compensation for trial-related injuries. While it is astounding that non-compliance to the existing regulations could have gone unnoticed by quality assurance staff as well as by the ethics committees and the regulator, for over six years, sudden enforcement of the regulation has thrown up issues and challenges that are difficult to resolve in the absence of an adequately debated and thought-through guidance. In implementing regulations for suo moto compensation, India is seeking to establish a practice not previously tested elsewhere in the world. There is no doubt that industry must support the idea of putting patients first, but procedural considerations in fixing causality and determining the quantum of compensation promise to raise questions of morality, ethics, and jurisprudence that will not be easy to answer. PMID:22347695

Mukherjee, Shoibal

2012-01-01

109

Compensation conundrum  

PubMed Central

Pressured by questions tabled in parliament that point to a lack of adequate enforcement of regulations, the DCG(I) has abruptly initiated action to ensure payment of compensation for trial-related injuries. While it is astounding that non-compliance to the existing regulations could have gone unnoticed by quality assurance staff as well as by the ethics committees and the regulator, for over six years, sudden enforcement of the regulation has thrown up issues and challenges that are difficult to resolve in the absence of an adequately debated and thought-through guidance. In implementing regulations for suo moto compensation, India is seeking to establish a practice not previously tested elsewhere in the world. There is no doubt that industry must support the idea of putting patients first, but procedural considerations in fixing causality and determining the quantum of compensation promise to raise questions of morality, ethics, and jurisprudence that will not be easy to answer.

Mukherjee, Shoibal

2012-01-01

110

Remote Sensing of the Earth 's Atmosphere by the Spaceborne Occultation Radiometer, ORA: Final Inversion Algorithm.  

PubMed

We describe the final inversion algorithm developed to process solar occultation data measured in 1992-1993 by the Occultation Radiometer (ORA) spaceborne experiment. First we develop a new method to improve the ORA total extinction altitude profiles retrieved with the previously described Natural Orthogonal Polynomial Expansion (NOPE) method. Using these improved profiles, we perform spectral inversion and obtain altitude density profiles for O(3) and NO(2) and extinction profiles for the aerosols. Validation of number density profiles between the Stratospheric Aerosol and Gas Experiment II (SAGE II) and the ORA shows satisfactory agreement. PMID:18357077

Fussen, D; Vanhellemont, F; Bingen, C

2001-02-20

111

A simple algorithm to estimate the effective regional atmospheric parameters for thermal-inertia mapping  

USGS Publications Warehouse

A method based solely on remote sensing data has been developed to estimate those meteorological effects which are required for thermal-inertia mapping. It assumes that the atmospheric fluxes are spatially invariant and that the solar, sky, and sensible heat fluxes can be approximated by a simple mathematical form. Coefficients are determined from least-squares method by fitting observational data to our thermal model. A comparison between field measurements and the model-derived flux shows the type of agreement which can be achieved. An analysis of the limitations of the method is also provided. ?? 1981.

Watson, K.; Hummer-Miller, S.

1981-01-01

112

Compensation of \\  

Microsoft Academic Search

Comments on G. C. Davison and R. B. Stuart’s speculation that some institutional directors may replace patient workers with workers from the outside because of the Wyatt v. Stickney case outlawing institutional peonage. Right to treatment standards set by this case required that patient workers be compensated according to the minimum wage provisions of the Fair Labor Standards Act.

Gottlieb C. Simon

1976-01-01

113

Compensation Inequality.  

National Technical Information Service (NTIS)

This paper uses Employment Cost Index (ECI) micro data to investigate inequality in compensation rates. The results help fill a gap in our knowledge on this issue, in that currently available data are not as comprehensive as those in the ECI. For example,...

B. Pierce

1999-01-01

114

Employee Compensation.  

ERIC Educational Resources Information Center

Presents an overview of selected literature about employee compensation. Highlights include the foundations of reward and recognition systems, incentive plans, problems with merit pay, a historical perspective on performance pay, evaluation criteria and processes, self-rating, job motivation and satisfaction, employee attitudes, collective…

Osif, Bonnie A.; Harwood, Richard L.

1995-01-01

115

Employee Compensation.  

ERIC Educational Resources Information Center

|Presents an overview of selected literature about employee compensation. Highlights include the foundations of reward and recognition systems, incentive plans, problems with merit pay, a historical perspective on performance pay, evaluation criteria and processes, self-rating, job motivation and satisfaction, employee attitudes, collective…

Osif, Bonnie A.; Harwood, Richard L.

1995-01-01

116

A new atmospheric ray-tracing algorithm and its use in VLBI analysis  

NASA Astrophysics Data System (ADS)

Due to recent improvements of numerical weather models (NWM), ray-tracing has become an interesting and feasible method for different scientific purposes. One application in geosciences is the estimation of tropospheric delays for the correction of space geodetic techniques. Here, we present and discuss the recently developed ray-tracing algorithm from the Institute of Geodesy and Geophysics (IGG) at Vienna University of Technology. We use numerical weather model data from the European Centre for Medium-Range Weather Forecasts (ECMWF) to estimate the tropospheric total delay by solving the Eikonal equation. In addition we discuss different methods and characteristics, such as interpolation methods, resolution of the data set and the use of different refractivity constants, and we present results and differences between a 2D- and 3D-ray-tracing algorithm. As quality validation we enter the derived tropospheric delays as a priori information in our VLBI analysis software package (Vienna VLBI Software). We analyze IVS Intensive sessions from July 2010 to October 2011 which are carried out for the estimation of UT1-UTC (DUT1). The measurement of this Earth rotation angle is needed in near real-time for the accurate prediction of Universal Time (UT1) as well as for navigation purposes. Due to the small number of observables per session most parameters, which are usually estimated in VLBI analyses, are fixed to their a priori values, which should be known as accurately as possible. As an external validation of our ray-traced delays we calculate Length-of-Day (LoD) from the VLBI-derived DUT1 values and compare these to LoD from GPS.

Madzak, M.; Nafisi, V.; Böhm, J.; Schuh, H.

2012-04-01

117

Impact of mixing height estimation on heterogeneous terrains with different algorithms and instruments on atmospheric transport models.  

NASA Astrophysics Data System (ADS)

The retrieval of mixing height [MH] is a common target of several scientific community all over the world. A strong effort is needed to the fact that modeling of MH generally fails introducing strong errors in the estimate of the concentrations of pollutants and green house gasses within the boundary layer. In Europe local meteorological services and international projects are implementing networks of instruments that can provide atmospheric profiles of different quantities. These networks will continuously provide data which could be used to constrain MH values. The current availability of atmospheric profiles of different nature, such as radiosondes, ground based lidar and ceilometers as well as satellites over Europe grant a spatial coverage that allow to estimate the impact of the knowledge of MH on transport models at synoptic scale of quantities as CO2 and CH4 mixing ratios. In this study we apply several algorithms to retrieve MH from different data sources: the ceilometers network installed by the German Weather Service; the data from CALIPSO satellite and all the WMO radio-soundings available over Europe during the IMECC (Infrastructure for Measurements of the European Carbon Cycle) in 2009. The values obtained from the optical instruments are validated using as reference the estimation retrieved by the virtual potential temperature profiles obtained by the radiosondes where co-location occurs and using statistical interpolation to evaluate the estimates from satellite and non co-located stations.. The impact of this estimates of MH on CO2 mixing ratios will be evaluated with the Stochastic Time Inverted Lagrangian Transport model (STILT) driven by WRF meteorology in comparison with in-situ measurements.

Biavati, G.; Kretschmer, R.; Gerbig, C.; Feist, D. G.

2012-04-01

118

Formulas for asymmetric lead and lag compensators  

Microsoft Academic Search

Lead and lag compensators are commonly used for classical loop shaping and as weighting functions for automated controller synthesis algorithms. The existing formulas for these compensators provide the capability of selecting phase at the frequency of maximum phase lead such that the phase peak or notch is symmetrical on the Bode plot phase chart. This paper develops easy-to-use formulas for

William Messner

2009-01-01

119

McCART: Monte Carlo code for atmospheric radiative transfer  

NASA Astrophysics Data System (ADS)

McCART is a numerical procedure to solve the radiative transfer equation for light propagation through the atmosphere especially developed to study the effect of the atmosphere on the response of hyperspectral sensors for remote sensing of the earth's surface. McCART is based on a single Monte Carlo simulation run for a reference layered plane non-absorbing atmosphere and a plane ground with uniform reflectance. The spectral response of the sensor for a given distribution of ground reflectance and for a specific profile of scattering and absorption properties of the atmosphere is obtained in a short time from the results of the Monte Carlo simulation, making use of scaling relationships and of symmetry properties. The response includes the effects of adjacent pixels. The results can be used to establish the limits of applicability of approximate algorithms for the processing and analysis of hyperspectral images. The algorithm can be also used to develop procedures of atmospheric compensation.

Nardino, Vanni; Del Bianco, Samuele; Martelli, Fabrizio; Guzzi, Donatella; Marcoionni, Paolo; Pippi, Ivan; Bruscaglioni, Piero; Zaccanti, Giovanni

2005-10-01

120

Speckle imaging through the atmosphere  

NASA Astrophysics Data System (ADS)

The atmosphere is the limiting factor in high-resolution ground-based optical telescope observations of objects in space. New speckle-imaging techniques allow astronomers to overcome atmospheric distortion and achieve the goal of diffraction-limited groundbased telescope performance. Studies and experiments at Lincoln Laboratory utilize speckle imaging for observation of near-earth satellites. Thousands of separate exposures, each 2 to 5 ms in duration, are collected within a few seconds. A computationally intensive algorithm is then used to reconstruct a single diffraction-limited image from the collection of separate exposures. The image-reconstruction process effectively removes the distortion imposed by the atmosphere. Photon noise, which limits the quality of image reconstruction, must be properly compensated by the actual detector calibration.

Beavers, Willet; Dudgeon, Dan E.; Beletic, James W.; Lane, Mark T.

1989-07-01

121

Speckle imaging through the atmosphere  

NASA Astrophysics Data System (ADS)

The atmosphere is the limiting factor in high-resolution ground-based optical telescope observations of objects in space. New speckle-imaging techniques allow astronomers to overcome atmospheric distortion and achieve the goal of diffraction-limited ground-based telescope performance. Studies and experiments at Lincoln Laboratory utilize speckle imaging for observation of near-earth satellites. Thousands of separate exposures, each 2 to 5 ms in duration, are collected within a few seconds. A computationally intensive algorithm is then used to reconstruct a single diffraction-limited image from the collection of separate exposures. The image-reconstruction process effectively removes the distortion imposed by the atmosphere. Photon noise, which limits the quality of image reconstruction, must be properly compensated by the actual detector calibration.

Beavers, W. I.; Dudgeon, D. E.; Beletic, J. W.; Lane, M. T.

122

Evaluation of the Advanced-Canopy-Atmosphere-Surface Algorithm (ACASA Model) Using Eddy Covariance Technique Over Sparse Canopy  

NASA Astrophysics Data System (ADS)

Land surface models are usually used to quantify energy and mass fluxes between terrestrial ecosystems and atmosphere on micro- and regional scales. One of the most elaborate land surface models for flux modelling is the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) model, which provides micro-scale as well as regional-scale fluxes when imbedded in a meso-scale meteorological model (e.g., MM5 or WRF). The model predicts vegetation conditions and changes with time due to plant responses to environment variables. In particular, fluxes and profiles of heat, water vapor, carbon and momentum within and above canopy are estimated using third-order equations. It also estimates turbulent profiles of velocity, temperature, humidity within and above canopy, and CO2 fluxes are estimated using a combination of Ball-Berry and Farquhar equations. The ACASA model is also able to include the effects of water stress on stomata, transpiration and CO2 assimilation. ACASA model is unique because it separates canopy domain into twenty atmospheric layers (ten layers within the canopy and ten layers above the canopy), and the soil is partitioned into fifteen layers of variable thickness. The model was mainly used over dense canopies in the past, so the aim of this work was to test the ACASA model over a sparse canopy as Mediterranean maquis. Vegetation is composed by sclerophyllous species of shrubs that are always green, with leathery leaves, small height, with a moderately sparse canopy, and that are tolerant at water stress condition. Eddy Covariance (EC) technique was used to collect continuous data for more than 3 years period. Field measurements were taken in a natural maquis site located near Alghero, Sardinia, Italy and they were used to parameterize and validate the model. The input values were selected by running the model several times varying the one parameter per time. A second step in the parameterization process was the simultaneously variation of some parameters. ACASA simulations were compared with measured fluxes of net radiation (Rn), sensible heat (H), latent heat (LE), soil heat (G), and CO2 fluxes at half-hourly time scale. Statistical analysis was made to evaluate model performance. Comparisons between simulated and measured values were evaluated using linear regression, the root mean squared error (RMSE), mean absolute error (RA), and mean bias error (MBE). Modeled data showed a good energy balance closure. ACASA estimates of net radiation were excellent. Sensible (H) and latent heat (LE) flux predictions exhibited only small differences between modeled and observed data. The ACASA model was able to capture the seasonal variation in CO2 flux. Net Ecosystem Exchange (NEE) showed the typical summer decrease due to drought induced water stress, and the simulations predicted the lower CO2 flux. Differences between simulated and observed fluxes were significant at 0.001 probability. ACASA simulations, therefore, are considered good. So, we can say that the use of ACASA to predict energy and mass fluxes between the vegetation and atmosphere is promising, and it could greatly improve our ability to estimate fluxes over natural ecosystems at both local and regional scales.

Marras, S.; Spano, D.; Sirca, C.; Duce, P.; Snyder, R.; Pyles, R. D.; Paw U, K. T.

2008-12-01

123

Atmospheric Turbulence Compensation of Point Source Images Using Asynchronous Stochastic Parallel Gradient Descent Technique on AMOS 3.6m Telescope  

NASA Astrophysics Data System (ADS)

Stochastic Parallel Gradient Descent Technique-based Adaptive Optics (SPGD-AO) system described in this presentation doesn't use conventional wave front sensor. It uses a metric signal collected by a single pixel detector placed behind a pinhole in the image plane to drive three deformable mirrors (DMs). The system is designed to compensate the image for turbulence effects. The theory behind this method is described in detail in J. Opt. Soc. Ame. A, 15,2745-2758,1998. However, this technique, while widely simulated and tested, was not verified so far in astronomical field site experiments. During the month of May 2007, a series of experiments using SPGD-AO compensation on stars at several elevation angles and turbulence levels, were conducted successfully at US Air Force Maui Optical and Supercomputing Site (AMOS) using 3.6 m telescope. Some of the results of these experiments will be described. This is the first time SPGD-AO systems have been tested and verified in astronomical field site experiments.

Voronstov, M.; Riker, J.; Carhart, G.; Gudimetla, V.; Berensev, L.; Weyrauch, T.

124

Hyperspectral material identification on radiance data using single-atmosphere or multiple-atmosphere modeling  

NASA Astrophysics Data System (ADS)

Reflectance-domain methods convert hyperspectral data from radiance to reflectance using an atmospheric compensation model. Material detection and identification are performed by comparing the compensated data to target reflectance spectra. We introduce two radiance-domain approaches, Single atmosphere Adaptive Cosine Estimator (SACE) and Multiple atmosphere ACE (MACE) in which the target reflectance spectra are instead converted into sensor-reaching radiance using physics-based models. For SACE, known illumination and atmospheric conditions are incorporated in a single atmospheric model. For MACE the conditions are unknown so the algorithm uses many atmospheric models to cover the range of environmental variability, and it approximates the result using a subspace model. This approach is sometimes called the invariant method, and requires the choice of a subspace dimension for the model. We compare these two radiance-domain approaches to a Reflectance-domain ACE (RACE) approach on a HYDICE image featuring concealed materials. All three algorithms use the ACE detector, and all three techniques are able to detect most of the hidden materials in the imagery. For MACE we observe a strong dependence on the choice of the material subspace dimension. Increasing this value can lead to a decline in performance.

Mariano, Adrian V.; Grossmann, John M.

2010-11-01

125

Adaptive tracking and compensation of laser spot based on ant colony optimization  

NASA Astrophysics Data System (ADS)

Because the effect of atmospheric scattering and atmospheric turbulence on laser signal of atmospheric absorption,laser spot twinkling, beam drift and spot split-up occur ,when laser signal transmits in the atmospheric channel. The phenomenon will be seriously affects the stability and the reliability of laser spot receiving system. In order to reduce the influence of atmospheric turbulence, we adopt optimum control thoughts in the field of artificial intelligence, propose a novel adaptive optical control technology-- model-free optimized adaptive control technology, analyze low-order pattern wave-front error theory, in which an -adaptive optical system is employed to adjust errors, and design its adaptive structure system. Ant colony algorithm is the control core algorithm, which is characteristic of positive feedback, distributed computing and greedy heuristic search. . The ant colony algorithm optimization of adaptive optical phase compensation is simulated. Simulation result shows that, the algorithm can effectively control laser energy distribution, improve laser light beam quality, and enhance signal-to-noise ratio of received signal.

Yang, Lihong; Ke, Xizheng; Bai, Runbing; Hu, Qidi

2009-05-01

126

Compensated deconvolution from wavefront sensing  

NASA Astrophysics Data System (ADS)

The U.S. Air Force has a continuing mission to obtain imagery of earth-orbiting objects. One of the means for obtaining this imagery is through the use of ground-based observatories. A fundamental problem associated with imaging objects through the atmosphere is that atmospheric turbulence inflicts a large, random aberration on the telescope which effectively limits the realizable resolution to that of a much smaller telescope. Several approaches have been taken to overcome these effects including pure post processing, pure adaptive optics, and hybrid techniques involving both adaptive optics and image post processing. One key result from past approaches is that partially compensated systems can be used in conjunction with image processing to overcome most of the optical effects of atmospheric turbulence while retaining nearly the performance of a fully compensated system. One hybrid approach is compensated deconvolution from wavefront sensing (CDWFS). This method uses wavefront sensor measurements in conjunction with short exposure images to improve the effective optical performance. This thesis formulates and executes a plan which allows fundamental questions regarding partially compensated adaptive optics performance to be answered. Specifically, imaging of extended objects using the CDWFS technique is investigated, through simulation. The simulation results demonstrate that the CDWFS technique can be used to reduce the required closed-loop bandwidth of an imaging system, permitting longer integration times in the wavefront sensor, and thus allowing dimmer objects to be imaged without the use of an artificial guidestar.

Thorson, Lori A.

1994-12-01

127

Cooperative Employee Compensation, 1999.  

National Technical Information Service (NTIS)

This report updates a 1993 study and looks at how education, cooperative function, and geography influence compensation of cooperative employees. Unlike the original report, this one addresses director compensation. Compensation varied from per diem and t...

B. L. Rotan

2001-01-01

128

Motion compensated projection reconstruction.  

PubMed

Over recent years, MRI has shown the capability for real-time applications. Although the acquisition times of fast MRI methods have been reduced significantly, patient motion during a magnetic resonance imaging (MRI) examination still causes artifacts in the image. In this paper, the effects of motion in MRI using a radial acquisition scheme are examined. It is shown that motion can be estimated without the use of additional measurement, based on the acquired projections only. A new reconstruction technique is introduced that integrates a motion compensation algorithm into the MR-reconstruction process, resulting in a significant reduction of blurring artifacts in the reconstructed images. The proposed method is applied to different kinds of motion such as kinetic joint studies. PMID:10332879

Schäffter, T; Rasche, V; Carlsen, I C

1999-05-01

129

Atmospheric correction of visible to middle-infrared EOS-MODIS data over land surfaces: Background, operational algorithm and validation  

Microsoft Academic Search

The NASA moderate resolution imaging spectroradiometer (MODIS) instrument will provide a global and improved source of information for the study of land surfaces with a spatial resolution of up to 250 m. Prior to the derivation of various biophysical parameters based on surface reflectances, the top of the atmosphere signals need to be radiometrically calibrated and corrected for atmospheric effects.

E. F. Vermote; N. El Saleous; C. O. Justice; Y. J. Kaufman; J. L. Privette; L. Remer; J. C. Roger; D. Tanré

1997-01-01

130

Radiation Exposure Compensation Program  

NSDL National Science Digital Library

This is the Justice Department's Radiation Exposure Compensation Program homepage. This site features information about the Radiation Exposure Compensation Act, including claimant categories, claim forms, and the Energy Employees Occupational Illness Compensation Program Act. This site also provides a table illustrating a summary of all claims received and compensation paid to date.

Program, U. S.

131

Windowed motion compensation  

Microsoft Academic Search

A new motion compensation technique using a window which satisfies the perfect reconstruction condition is proposed. THe conventional motion compensation using rectangular blocks often gives discontinuities between neighboring motion compensation blocks in the predicted image. The proposed method is based on a window operation to the data which overlaps an area of the conventional motion compensation block. Computer simulation is

Hiroshi Watanabe; Sharad Singhal

1991-01-01

132

Essays in Executive Compensation  

Microsoft Academic Search

This dissertation focuses on how executive compensation is designed and its implications for corporate finance and government regulations. Chapter 2 analyzes several proposals to restrict CEO compensation and calibrates two models of executive compensation that describe how firms would react to different types of restrictions. We find that many restrictions on CEO compensation would have unintended consequences. Restrictions on total

D. Zhang

2012-01-01

133

Interferometric microwave radiometers for high-resolution imaging of the atmosphere brightness temperature based on the adaptive Capon signal processing algorithm.  

PubMed

Passive microwave remote sensing from satellites and ground stations has contributed uniquely, and substantially, to the study of atmospheric chemistry, meteorology, and environmental monitoring. As user requirements are raised, in terms of the accuracy and the spatial resolution, a mechanically scanning radiometer, with a real aperture, becomes impractical due to the requirement for a very large antenna size. However, an aperture synthesis interferometric radiometer presents a valuable alternative. The work presented in this paper was devoted to high spatial resolution imaging, using the 37 GHz band interferometric radiometer, developed by ourselves. The spatially adaptive Capon beamforming method was exploited for the imaging, which outperformed the conventional Fourier Transform method. We concluded that the high spatial resolution imaging of the brightness temperature of the atmosphere could be accomplished with an interferometric radiometer equipped with the developed Capon beamforming imaging algorithm. PMID:15038536

Park, Hyuk; Choi, Junho; Katkovnik, Vladimir; Kim, Yonghoon

2004-03-01

134

Image restoration technique for motion-compensated frame averaged data collected by 3D flash ladar imaging system  

NASA Astrophysics Data System (ADS)

A new image restoration algorithm is proposed to remove the effect of atmospheric turbulence on motion-compensated frame averaged data collected by a three dimensional FLASH Laser Radar (LADAR) imaging system. The algorithm simultaneously arrives at an enhanced image as well as Fried's seeing parameter through an Expectation Maximization (EM) technique. Unlike blind deconvolution algorithms that operate only on two dimensional images, this technique accounts for both the spatial and temporal mixing that is caused by the atmosphere through which the system is imaging. Additionally, due to the over-determined nature of this problem, the point-spread function parameterized by Fried's seeing parameter can be deduced without the requirement for additional assumptions or constraints. The utility of the approach lies in its application to laser illuminated imaging where processing time is important.

Neff, Brian J.; Cain, Stephen C.

2012-10-01

135

Ecomp Executive Compensation Database  

NSDL National Science Digital Library

The Ecomp Executive Compensation Database allows users to research the compensation and net-worth of executives. Users may search the database by company name or ticker symbol, as well as by state, sector, and industry pull-down menus. Search returns list compensation summaries for the top executives, including salary, bonus, and total compensation. Clicking on the executive's name will give a more detailed summary, including restricted stock, LTIP payouts, and value realized for options exercised. All numbers are for 1999.

136

A Hybrid Spectral\\/Finite-Volume Algorithm for Large-Eddy Simulation of Scalars in the Atmospheric Boundary Layer  

Microsoft Academic Search

Pseudospectral methods are frequently used in the horizontal directions in large-eddy simulation of atmospheric flows. However,\\u000a the same approach often creates unphysical oscillations for scalar fields if there are horizontal heterogeneities in the sources\\u000a and\\/or sinks, as is usual in air pollution problems. A hybrid approach is developed to combine the use of pseudospectral representation\\u000a of the velocity field and

Marcelo Chamecki; Charles Meneveau; Marc B. Parlange

2008-01-01

137

A closed-loop selective harmonic compensation for active filters  

Microsoft Academic Search

This paper proposes a control algorithm for parallel active power filters, based on current-controlled pulsewidth-modulated converters, which allows precise compensation of selected harmonic currents produced by distorting loads. The approach is based on the measurement of line currents and performs the compensation of the selected harmonics using closed-loop synchronous frame controllers. Thanks to the closed-loop operation, full compensation of the

Paolo Mattavelli

2001-01-01

138

Movement Compensated Interframe Prediction for NTSC Color TV Signals  

Microsoft Academic Search

This paper presents techniques for interframe prediction of color NTSC signals using motion estimation and compensation techniques. A key element in movement-compensated prediction is the displacement estimation algorithm. A number of techniques for performing this estimation have been presented in the literature [1]-[13]. Some new techniques giving improved performance are presented in this paper. Also, a movement-compensated composite prediction approach

S. Sabri

1984-01-01

139

Motion Compensation in Minimally Invasive Robotic Surgery  

Microsoft Academic Search

Abstract: Minimally invasive beating heart surgery allows a very sparing operation, butincreases the requirements for the surgeon: The remaining motion of the mechanicallystabilized beating heart makes fast and safe surgery di#cult. Thegoal of an advanced robotic surgery system is to compensate for this motion.This work presents control and vision algorithms necessary for such novel roboticsurgery applications.

Tobias Johannes Ortmaier

2003-01-01

140

Bias compensated least squares estimate of the center of rotation  

Microsoft Academic Search

It is shown that a recently published least squares method for the estimation of the average center of rotation is biased. Consequently, a correction term is proposed, and an iterative algorithm is derived for finding a bias compensated solution to the least squares problem.The accuracy of the proposed bias compensated least squares method is compared to the previously proposed least

Kjartan Halvorsen

2003-01-01

141

Motion compensated reconstructions of calcified coronary plaques in cardiac CT  

Microsoft Academic Search

In order to obtain motion-compensated reconstructions of calcified coronary plaques in cardiac CT, the dynamic trajectory of the plaque must be known rather accurately. The purpose of this study is to evaluate whether the dynamic trajectories of a plaque extracted from reconstructions provided by a previously developed tracking algorithm can be used for obtaining motion-compensated reconstructions of this plaque. A

Martin King; Xiaochuan Pan; Maryellen Giger; Kenji Suzuki

2007-01-01

142

Inclined plane walking compensation for a humanoid robot  

Microsoft Academic Search

This paper suggested the simple compensation algorithm for a humanoid robot when walking on an inclined plane. Motion transition of the robot for varying slope can be achieved from adjusting the center of mass of the robot forward\\/backward by compensating the robot's ankle. This proposed method used the feedback from the accelerometer in the robot's body to detect the inclination

Nattapong Kaewlek; Thavida Maneewarn

2010-01-01

143

Coupling between the University of California, Davis, Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) and MM5: Preliminary Results for July 1998 for Western North America.  

NASA Astrophysics Data System (ADS)

The University of California, Davis, Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) is coupled to the fifth-generation Pennsylvania State University-National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5) as a land surface scheme. Simulations for July 1998 over western North America show that this coupling, the first between a mesoscale model and a land surface model of this complexity, is successful. Comparisons among model output, National Centers for Environmental Prediction-NCAR reanalysis fields, and station data show that MM5-ACASA generally reproduces near-surface temperature in a realistic fashion, but with a stronger diurnal cycle than observations suggest. A control run using the existing Louis/European Centre for Medium-Range Weather Forecasts land surface formulation produces unrealistically low temperatures associated with high latent heating and precipitation amounts over much of the model domain. Simulations of heat and moisture fluxes using the Biosphere-Atmosphere Transfer Scheme (BATS) are generally comparable to ACASA, but near-surface air temperatures reveal excessively warm conditions. Low specific-humidity values over land in both MM5-ACASA and MM5-BATS simulations and low oceanic values in all three simulations suggest a possible dry bias in MM5. Comparison statistics between modeled near-surface climatological behavior and associated fluxes at three sites show that MM5-ACASA, out of the three simulations, agrees most with observations. Sensitivity tests show that MM5 is generally more sensitive to the choice of surface scheme than it is to soil moisture initialization. Comparisons of mean carbon dioxide fluxes reveal that ACASA can be a useful tool in examining the terrestrial carbon cycle.

Pyles, R. David; Weare, Bryan C.; Tha Paw U, Kyaw; Gustafson, William

2003-05-01

144

Rationalizing vaccine injury compensation.  

PubMed

Legislation recently adopted by the United States Congress provides producers of pandemic vaccines with near-total immunity from civil lawsuits without making individuals injured by those vaccines eligible for compensation through the Vaccine Injury Compensation Program. The unusual decision not to provide an alternative mechanism for compensation is indicative of a broader problem of inconsistency in the American approach to vaccine-injury compensation policy. Compensation policies have tended to reflect political pressures and economic considerations more than any cognizable set of principles. This article identifies a set of ethical principles bearing on the circumstances in which vaccine injuries should be compensated, both inside and outside public health emergencies. A series of possible bases for compensation rules, some grounded in utilitarianism and some nonconsequentialist, are discussed and evaluated. Principles of fairness and reasonableness are found to constitute the strongest bases. An ethically defensible compensation policy grounded in these principles would make a compensation fund available to all individuals with severe injuries and to individuals with less-severe injuries whenever the vaccination was required by law or professional duty. PMID:18154587

Mello, Michelle M

2008-01-01

145

SPATIALLY ADAPTIVE FLICKER COMPENSATION FOR ARCHIVED FILM SEQUENCES USING A NONLINEAR MODEL  

Microsoft Academic Search

We present an algorithm suitable for the compensation of flicker in archived film sequences. The proposed method is a substantial improvement over our previous work which adopted a nonlinear approach to flicker compensation motivated by fundamental principles of photographic image registration. The improvements include reliability weighting, spatial adaptation and motion compensated weighting. We present experimental evidence which suggests that our

Guillaume Forbin; Theodore Vlachos; Simon Tredwell

146

The Compensation Model for Default-Risk of Corporate Bonds in China under Kalman Filter  

Microsoft Academic Search

The default compensation of corporate bonds is a significant part of risk management. In this research, algorithm of the Kalman filter is applied in modeling of jump-risk compensation. Default probability and default intensity are two important variables for the jump-risk compensation. In the modeling process, the parameter method of maximum likelihood estimation is used to obtain the default probability, and

Kaihao Liang; Kin Keung Lai

2009-01-01

147

Hybrid global-local motion compensated frame interpolation for low bit rate video coding  

Microsoft Academic Search

A hybrid global–local motion compensated frame interpolation (HMCI) scheme for low bit rate video coding is proposed in this paper. Different from most other global–local motion compensation algorithms, which were performed at the encoder end, the proposed scheme works solely on the decoded video stream. Thus, it can be applied to any MCP (motion compensated prediction) based standard coders without

Shan Liu; C.-C. Jay Kuo; Jongwon Kim

2003-01-01

148

Realtime motion compensation for ROV-based tele-operated underwater manipulators  

Microsoft Academic Search

This paper presents a novel underwater movement compensation algorithm for stabilization of manipulator position utilizing not ROV movements for disturbance compensation, but overlaid manipulator movements. A model based estimator is used to predict vehicle movement and provide the manipulation system with the necessary time to compensate for the estimated motion. It describes the conceptual benefits of this approach compared with

Marc Hildebrandt; Leif Christensen; Jochen Kerdels; Jan Albiez; Frank Kirchner

2009-01-01

149

Gmti Motion Compensation  

DOEpatents

Movement of a GMTI radar during a coherent processing interval over which a set of radar pulses are processed may cause defocusing of a range-Doppler map in the video signal. This problem may be compensated by varying waveform or sampling parameters of each pulse to compensate for distortions caused by variations in viewing angles from the radar to the target.

Doerry, Armin W. (Albuquerque, NM)

2004-07-20

150

Racing wheelchair crown compensation.  

PubMed

This paper is concerned with the directional stability of racing wheelchairs on crown roads. Three types of crown compensators are described and evaluated: the push-pull, the push-push, and the pull-pull. It was found that the push-push and the push-pull types of compensators have the most desirable characteristics, and were, in general, safer than the pull-pull type. In addition, the equations necessary to specify the minimum spring force required to compensate for the downhill turning moment, were derived and compared to the actual preset forces for the various compensators presently in use. It was found that the force required to maintain directional stability was less than that to deflect the crown compensator. This was due to the preference of athletes for additional stiffness needed for disturbance rejection, and to help compensate for any asymmetry in their stroke kinematics. It was also more cost-effective for the manufacturer to build stiffer-than-necessary crown compensators so that a range of individual and racing wheelchair combinations could use the same crown compensator. PMID:2918485

Cooper, R A

1989-01-01

151

Adaptive temperature compensation of GPS disciplined quartz and rubidium oscillators  

Microsoft Academic Search

An algorithm for performing adaptive temperature and ageing compensation of GPS disciplined oscillators is presented. The algorithm is based on a recursive implementation of linear regression, so it is computationally efficient. In addition, essentially unlimited equivalent averaging times are realizable using this approach while storage requirements remain small and constant. Implementation of time varying averaging times is made simple as

B. M. Penrod

1996-01-01

152

Feed-forward Compensation of load and parameter variations of electric drive  

Microsoft Academic Search

The paper presents a method to compensate effects caused by slow varying loads and plant parameters drift as well as by detuned controller using a simple yet robust algorithm in voltage controlled electric drives. In case of known variations an analytical expression of pre-computed feed-forward compensation voltage is derived, while in presence of unknown disturbances the control algorithm uses a

Alon Kuperman; Yoram Horen; Saad Tapuchi; Uri Suissa

2008-01-01

153

A Managerial Approach to Compensation  

ERIC Educational Resources Information Center

The article examines the major external forces constraining equitable employee compensation, sets forth the classical employee compensation assumptions, suggests somewhat more realistic employee compensation assumptions, and proposes guidelines based on analysis of these external constraints and assumptions. (Author)

Wolfe, Arthur V.

1975-01-01

154

Temperature Effects and Compensation-Control Methods  

PubMed Central

In the analysis of the effects of temperature on the performance of microgyroscopes, it is found that the resonant frequency of the microgyroscope decreases linearly as the temperature increases, and the quality factor changes drastically at low temperatures. Moreover, the zero bias changes greatly with temperature variations. To reduce the temperature effects on the microgyroscope, temperature compensation-control methods are proposed. In the first place, a BP (Back Propagation) neural network and polynomial fitting are utilized for building the temperature model of the microgyroscope. Considering the simplicity and real-time requirements, piecewise polynomial fitting is applied in the temperature compensation system. Then, an integral-separated PID (Proportion Integration Differentiation) control algorithm is adopted in the temperature control system, which can stabilize the temperature inside the microgyrocope in pursuing its optimal performance. Experimental results reveal that the combination of microgyroscope temperature compensation and control methods is both realizable and effective in a miniaturized microgyroscope prototype.

Xia, Dunzhu; Chen, Shuling; Wang, Shourong; Li, Hongsheng

2009-01-01

155

Simultaneous retrieval of atmospheric profiles, land-surface temperature, and surface emissivity from Moderate-Resolution Imaging Spectroradiometer thermal infrared data: extension of a two-step physical algorithm.  

PubMed

An extension to the two-step physical retrieval algorithm was developed. Combined clear-sky multitemporal and multispectral observations were used to retrieve the atmospheric temperature-humidity profile, land-surface temperature, and surface emissivities in the midwave (3-5 microns) and long-wave (8-14.5 microns) regions. The extended algorithm was tested with both simulated and real data from the Moderate-Resolution Imaging Spectroradiometer (MODIS) Airborne Simulator. A sensitivity study and error analysis demonstrate that retrieval performance is improved by the extended algorithm. The extended algorithm is relatively insensitive to the uncertainties simulated for the real observations. The extended algorithm was also applied to real MODIS daytime and nighttime observations and showed that it is capable of retrieving medium-scale atmospheric temperature water vapor and retrieving surface temperature emissivity with retrieval accuracy similar to that achieved by the Geostationary Operational Environmental Satellite (GOES) but at a spatial resolution higher than that of GOES. PMID:11908219

Ma, Xia L; Wan, Zhengming; Moeller, Christopher C; Menzel, W Paul; Gumley, Liam E

2002-02-10

156

Real-time adaptive radiometric compensation.  

PubMed

Recent radiometric compensation techniques make it possible to project images onto colored and textured surfaces. This is realized with projector-camera systems by scanning the projection surface on a per-pixel basis. Using the captured information, a compensation image is calculated that neutralizes geometric distortions and color blending caused by the underlying surface. As a result, the brightness and the contrast of the input image is reduced compared to a conventional projection onto a white canvas. If the input image is not manipulated in its intensities, the compensation image can contain values that are outside the dynamic range of the projector. These will lead to clipping errors and to visible artifacts on the surface. In this article, we present an innovative algorithm that dynamically adjusts the content of the input images before radiometric compensation is carried out. This reduces the perceived visual artifacts while simultaneously preserving a maximum of luminance and contrast. The algorithm is implemented entirely on the GPU and is the first of its kind to run in real-time. PMID:17993705

Grundhöfer, Anselm; Bimber, Oliver

157

Federal Employees' Compensation Act.  

PubMed

The Federal Employees' Compensation Act (FECA) program provides wage loss compensation and payments for medical treatment to federal civilian employees. Administered by the Department of Labor (DOL), FECA covers over 2.7 million federal employees in more than 70 different agencies. FECA costs rose from $1.4 billion in 1990 to $2.6 in 2006, while the federal workforce remained essentially unchanged. While federal civilian employees represent only 2.1% of all workers eligible for workers' compensation benefits, federal programs account for 6% of the benefits paid. Disability benefits under FECA are far greater than those in the state workers' compensation programs. The benefit payments often exceed the former salary of the injured employee. The last congressional hearings on the FECA program were held over thirty years ago. It is unlikely that Congressional review will occur any time soon, as the entrenched bureaucracy that benefits from the FECA program defines and protects its future. PMID:19496485

Ladou, Joseph

158

Temperature Compensated Piezoelectric Materials.  

National Technical Information Service (NTIS)

In order to search for new temperature compensated materials for surface acoustic wave (SAW) devices with low ultrasonic attenuation and high electro-mechanical coupling, the following experimental and theoretical investigation were carried out. Extensive...

G. R. Barsch K. E. Spear

1976-01-01

159

Temperature Compensated Piezoelectric Materials.  

National Technical Information Service (NTIS)

In order to search for new temperature compensated materials for surface acoustic wave (SAW) devices with low ultrasonic attenuation and high electromechanical coupling, the following experimental and theoretical investigations were carried out: Extensive...

G. R. Barsch K. E. Spear

1977-01-01

160

Temperature Compensated Piezoelectric Materials.  

National Technical Information Service (NTIS)

In order to search for new temperature compensated materials for surface acoustic wave (SAW) devices with low ultrasonic attenuation and high electromechanical coupling, the following experimental and theoretical investigations were carried out: (i) Exten...

G. R. Barsch K. E. Spear

1976-01-01

161

Glossary of Compensation Terms.  

National Technical Information Service (NTIS)

Individuals interested in employee compensation are likely to encounter the terms listed in this glossary. Definitions are brief and may not reflect all usage. Some terms have a specific legal meaning, either through legislative enactment or judicial inte...

1998-01-01

162

Cooperative Employee Compensation.  

National Technical Information Service (NTIS)

The study looks at how education, cooperative function, and geography influence patterns in compensating cooperative employees. Generally, cooperative respondents in the West reported employees had the highest median salaries. Job responsibility, decision...

B. L. Rotan

1993-01-01

163

Managing Employee Compensation Risk  

Microsoft Academic Search

We analyze a principal-agent model in which the principal (e.g., shareholders) and the agent (e.g., an employee) can personally\\u000a trade securities tied to the outcome of an uncontrollable event affecting output. The model is employed to address two questions.\\u000a First, under what conditions does compensation risk management at the individual level substitute for compensation risk management\\u000a at the firm level?

Paul E. Fischer

2000-01-01

164

Compensation in Workflow Nets  

Microsoft Academic Search

We present a formal model to specify compensation of workflows: Each acyclic workflow net W (as defined by v.d. Aalst) is canonically extended to a net W\\u000a ?+?, representing the potential occurrence of failures, and the compensation of so-far executed actions. We show that the construction\\u000a is compositional and correct, i.e. meets the expected properties.

Baver Acu; Wolfgang Reisig

2006-01-01

165

Compensation for transducer effects in optoacoustic tomography  

NASA Astrophysics Data System (ADS)

Optoacoustic Tomography (OAT) is a hybrid imaging modality that combines the advantages of both optical imaging and ultrasound imaging techniques. Most existing reconstruction algorithms for OAT assume pointlike transducers, which may result in conspicous image blurring and distortions in certain applications. In this work, a new imaging model that incorporates the transducer response is employed for image reconstruction. Computer-simulation studies demonstrate that the new reconstruction method can effectively compensate for image resolution degradation associated with the transducer response.

Wang, Kun; Anastasio, Mark A.; Ermilov, Sergey A.; Brecht, Hans-Peter; Su, Richard; Oraevsky, Alexander A.

2010-02-01

166

Atmospheric Hydrocodes Using FCT Algorithms.  

National Technical Information Service (NTIS)

Several recently developed multidimensional hydrocodes for low-altitude nuclear-explosion phenomenology are described and their performance characteristics are discussed. These codes all use flux-corrected transport techniques because of the strong shocks...

J. P. Boris J. H. Gardner S. Zalesak

1975-01-01

167

Hysteresis compensation for a piezoelectric fiber optic voltage sensor  

NASA Astrophysics Data System (ADS)

We present details of numerical techniques developed to compensate the effects of hysteresis experienced by a hybrid piezoelectric fiber optic voltage sensor. The techniques, implemented using a real-time signal processing system, are tested and their effectiveness evaluated experimentally. The best of the proposed algorithms provides phase error compensation from approximately 7 to nearly 0 deg, and allows us to perform sensor calibration to achieve accuracy better than 0.5% (full scale output).

Fusiek, G.; Niewczas, Pawel; Dziuda, L.; McDonald, James R.

2005-11-01

168

Compensating specular highlights for non-Lambertian projection surfaces  

NASA Astrophysics Data System (ADS)

This paper concerns the compensation of specular highlight for handheld image projectors. By employing a projector-camera configuration, where the camera is aligned with the viewer, the distortion caused by nonideal (e.g., colored, reflective) projection surfaces can be estimated from the captured image and compensated for accordingly to improve the projection quality. This works fine when the viewing direction relative to the system is fixed. However, the compensation becomes inaccurate when this condition changes, because the position of the specular highlight changes as well. We propose a novel method that, without moving the camera, can estimate the specular highlight seen from any position and integrate it with Grossberg's radiometric compensation framework to demonstrate how view-dependent compensation can be achieved. Extensive results, both objective and subjective, are provided to demonstrate the performance of the proposed algorithm.

Kao, Chen-Tai; Huang, Tai-Hsiang; Lee, Hua; Chen, Homer H.

2013-01-01

169

Integrated adaptive feed-forward control of atmospheric turbulence excited rigid body motions and structural vibrations on a large transport aircraft  

Microsoft Academic Search

An adaptive feed-forward controller for simultaneous compensation of atmospheric turbulence excited rigid body motions and structural vibrations is designed. Proposed feed-forward control is intended as an add-on to current gust load alleviation systems. The objectives thereby are increased passenger comfort and handling qualities, as well as a more efficient reduction of dynamic wing loads. A steepest descent algorithm is applied

Andreas Wildschek; Rudolf Maier

2008-01-01

170

On adaptive friction compensation  

Microsoft Academic Search

A method of compensating for friction in control systems is presented. The method entails the use of an observer to estimate the friction which is modeled as a constant times the sign of the velocity. The purpose of the observer is to estimate this constant. The observer model is selected to ensure that the error in estimation of the friction

Bernard Friedland; Young-Jin Park

1992-01-01

171

The Compensation Question  

ERIC Educational Resources Information Center

|Over the past few years, as cash-strapped states and school districts have faced tough budget decisions, spending on teacher compensation has come under the microscope. The underlying question is whether, when you take everything into account, today's teachers are fairly paid, underpaid, or overpaid. In this forum, two pairs of respected…

Richwine, Jason; Biggs, Andrew; Mishel, Lawrence; Roy, Joydeep

2012-01-01

172

The Compensated Balun  

Microsoft Academic Search

The compensated balun, first described by Marchand and later reinvented by Roberts, is found to have much broader band-widths than realized by either author. This balun is analyzed here and the parameters which determine its bandwidths are discussed. Curves are presented which allow the design of a balun having any bandwidth. The practical considerations which preclude realization of infinite bandwidths

G. Oltman

1966-01-01

173

Motion compensation in radiotherapy.  

PubMed

Image-guided radiotherapy (IGRT) has helped to dramatically reduce safety margins compensating for positioning uncertainties in radiotherapy. A remaining issue posing problems for photon radiotherapy (RT), but even more so for particle RT, is target motion during treatment delivery. This review outlines the various strategies currently being developed or already in clinical use to compensate for organ motion, predominantly breathing-induced motion of liver and lung targets. Several motion compensation strategies have recently been introduced clinically. Among these are optimized margins encompassing the individual range of target motion, treatment under breath hold, gated treatments, and tumor tracking with a dedicated treatment device. A variety of surveillance strategies for gating and tracking, such as indirect tracking with external fiducial markers and surface scanning devices, direct tracking with implanted electromagnetic markers, fiducial markers, and fluoroscopy, and ultrasound-based tracking are already in clinical use or are under development. Tracked treatment with linear accelerators based on tumor-synchronous MLC- or treatment-table adaptation are moving toward clinical use. A multitude of strategies to reduce the impact of intrafractional target motion in RT have been developed and are increasingly being used clinically. The clinical introduction of advanced strategies currently under development is imminent. After IGRT minimized treatment margins for static tumors, the implementation of motion compensation strategies will achieve the same for targets being subject to intrafractional breathing-induced motion. PMID:22694199

Guckenberger, Matthias; Richter, Anne; Boda-Heggemann, Judit; Lohr, Frank

2012-01-01

174

Backlash compensator mechanism  

DOEpatents

Mechanism which compensates for backlash error in a lead screw position indicator by decoupling the indicator shaft from the lead screw when reversing rotation. The position indicator then displays correct information regardless of the direction of rotation of the lead screw.

Chrislock, Jerry L. (Bethel Island, CA)

1979-01-01

175

An adaptive scheme for compensation of loss of effectiveness of flight control effectors  

Microsoft Academic Search

In this paper we present two stable adaptive tracking control algorithms for compensation of loss of effectiveness of control effectors in flight control applications. The overall approach is based on suitable failure parameterization, control law and adaptive algorithm design, and Lyapunov analysis of the properties of the overall system. The proposed adaptive algorithms are based on parameter-adaptive and variable-structure control

Jovan D. BoSkoviC; Raman K. Mehra

2001-01-01

176

Fixed series compensation monitoring system  

Microsoft Academic Search

Fixed Series Compensation (FSC) employs capacitors to compensate the inductive reactance of transmission lines, being a highly effective and economical means of improving power transfer. A Fixed Series Compensation Monitoring System has as objective the knowledge of the actual physical state of this FACTS (Flexible AC Transmission Systems) system and diagnose the evolution of components damage, so that it is

A. L. P. de Oliveira

2008-01-01

177

Deferred Compensation Becomes More Common  

ERIC Educational Resources Information Center

A key part of the compensation package for some college and university presidents is money that they do not receive in their paychecks. Formally known as deferred compensation, such payments can take many forms, including supplemental retirement pay, severance pay, or even bonuses. With large institutions leading the way, deferred compensation has…

June, Audrey Williams

2006-01-01

178

Deferred Compensation Becomes More Common  

ERIC Educational Resources Information Center

|A key part of the compensation package for some college and university presidents is money that they do not receive in their paychecks. Formally known as deferred compensation, such payments can take many forms, including supplemental retirement pay, severance pay, or even bonuses. With large institutions leading the way, deferred compensation

June, Audrey Williams

2006-01-01

179

An efficient error compensation system for CNC multi-axis machines  

Microsoft Academic Search

To enhance a machine’s ability for a precision machining task, an efficient compensation scheme that takes all error sources into account is needed. In this study, an effective static\\/quasi-static error compensation system composed of an interpolation algorithm based on shape functions for error prediction, and a recursive software compensation procedure, was developed. The new error prediction scheme is efficient enough

Shih-Ming Wang; Yuan-Liang Liu; Yuan Kang

2002-01-01

180

On the effect of environment-triggered population diversity compensation methods for memory enhanced UMDA  

Microsoft Academic Search

This paper focuses on the effect of population diversity to environment identification-based memory scheme (EI-MMS) which heuristically compensates population diversity through the storage and retrieving process of historic information. We introduced several diversity compensation measures and combined them with EI-MMS based univariate marginal distribution algorithm (UMDA) from two aspects. First, a basic diversity compensation measure was used to fight against

Xingguang Peng; Demin Xu; Fubin Zhang

2011-01-01

181

Complexity-reduced digital nonlinear compensation for coherent optical system  

NASA Astrophysics Data System (ADS)

The high complexity of conventional intra-channel nonlinearity compensation algorithms, such as back-propagation, is considered as the major obstacle for the implementation. To reduce the complexity, perturbation analysis is applied because it considers multi-span transmission as one stage. In those perturbation based algorithms, such as perturbation back-propagation (PBP) and perturbation pre-distortion, the number of required compensation stage is much less than that of conventional back-propagation. To reduce the complexity further, the multi-tap finite impulse response filter (FIR) in PBP is replaced with one-tap infinite impulse response (IIR) filter. The number of required compensation stage of IIR PBP is only 15% of conventional back-propagation, whereas the complexity of each stage is almost same. In perturbation pre-distortion, the proposed perturbation combination reduces the number of terms from 19732 to 41, whereas no performance degradation is observed.

Tao, Zhenning; Dou, Liang; Yan, Weizhen; Fan, Yangyang; Li, Lei; Oda, Shoichiro; Akiyama, Yuichi; Nakashima, Hisao; Hoshida, Takeshi; Rasmussen, Jens C.

2013-01-01

182

Analysis and modeling of thermal-blooming compensation  

NASA Astrophysics Data System (ADS)

The present evaluation of recent progress in the analysis and computer modeling of adaptive optics hardware applicable to compensation for thermal blooming gives attention to an analytical theory of phase-compensation instability (PCI) that incorporates the actuator geometry of real deformable mirrors, as well as to novel algorithms for computer simulation of adaptive optics hardware. An analytical formalism is presented which facilitates the quantitative analysis of the effects of the adaptive-optics control system on PCI, and leads to both a universality theorem for PCI growth rates and the realization that wind exerts a greater influence on PCI growth rates than previously suspected. The analysis and algorithms are illustrated by the results of the time-dependent adaptively-compensated laser propagation code for thermal blooming, MOLLY, which has been optimized for the Cray-2 supercomputer.

Schonfeld, Jonathan F.

1990-05-01

183

Block-classified motion compensation scheme for digital video  

SciTech Connect

A novel scheme for block-based motion compensation is introduced in which a block is classified according to the energy that is directly related to the motion activity it represents. This classification allows more flexibility in controlling the bit rate arid the signal-to-noise ratio and results in a reduction in motion search complexity. The method introduced is not dependent on the particular type of motion search algorithm implemented and can thus be used with any method assuming that the underlying matching criteria used is minimum absolute difference. It has been shown that the method is superior to a simple motion compensation algorithm where all blocks are motion compensated regardless of the energy resulting after the displaced difference.

Zafar, S. [Argonne National Lab., IL (United States). Mathematics and Computer Science Div.; Zhang, Ya-Qin [David Sarnoff Research Center, Princeton, NJ (United States); Jabbari, B. [George Mason Univ., Fairfax, VA (United States). Dept. of Electrical and Computer Engineering

1996-03-01

184

Motion Compensated Fan-Beam Reconstruction for Nonrigid Transformation  

Microsoft Academic Search

We develop an approximate fan-beam algorithm to reconstruct an object with time-dependent nonrigid transformation such as the heart. The method is in the form of derivative back- projection filtering with compensation of affine transformations on a local basis. Computer simulations showed the proposed method significantly reduces image artifact due to nonrigid motion. Therefore, with very little motion artifact, the proposed

Katsuyuki Taguchi; Hiroyuki Kudo

2008-01-01

185

Vector field interpolation for cardiac motion compensated reconstruction  

Microsoft Academic Search

Cardiac CT image reconstruction suffers from motion artifacts due to heart motion during acquisition. In order to mitigate these effects, it is common practice to acquire with fast gantry rotation and do gated reconstruction. In addition, it is possible to estimate heart motion retrospectively and to incorporate that information in a motion compensated reconstruction (MCR). However, if shape tracking algorithms

Peter Forthmann; Udo van Stevendaal; Michael Grass; Thomas Koohler

2008-01-01

186

Motion estimation and compensation optimization on IA32 CPU  

Microsoft Academic Search

Motion estimation (ME) and compensation (MC) is critical to the performance of an encoder, because the procedure is computationally intensive. To reduce the calculation, people work out some kinds of fast search algorithms for motion estimation, and dramatically improve the performance. This paper uses the Intel Pentium CPU's MMX, XMM registers and some Single Instruction Multiple Data (SIMD) instructions to

Yihua Du; Chang Liu

2005-01-01

187

Automatic illumination and color compensation using mean shift and sigma filter  

Microsoft Academic Search

We present a novel framework for automatic illumination and color compensation algorithm using mean shift and the sigma filter (ICCMS) to restore distorted images taken under the arbitrary lighting conditions. The proposed method is effective for appropriate illumination compensation, vivid color restoration, artifacts suppression, automatic parameter estimation, and low computational cost for HW implementation. We show the efficiency of the

Heechul Han; Kwanghoon Sohn

2009-01-01

188

Robust adaptive numerical compensation for friction and force ripple in permanent-magnet linear motors  

Microsoft Academic Search

This paper describes a robust adaptive compensation method for friction and force ripple present in the dynamics of permanent-magnet linear motors. The method is used in ultraprecise positioning applications. The compensation algorithm consists of a PID component and an adaptive component for estimating friction and force ripple. The adaptive component is continuously refined on the basis of just prevailing input

K. K. Tan; S. N. Huang; T. H. Lee

2002-01-01

189

Interframe video coding using overlapped motion compensation and perfect reconstruction filter banks  

Microsoft Academic Search

Interframe video coders using the discrete cosine transform (DCT) and motion compensation (MC) produce block artifacts in the decoded video at low bit-rates. Results on lapped orthogonal transforms (LOTs) suggest that they can reduce these artifacts. However, LOTs are difficult to use efficiently with motion compensation because of block overlap. The authors propose a new video coding algorithm that forms

Hirohisa Jozawa; Hiroshi Watanabe; Sharad Singhal

1992-01-01

190

Robust transmission of video sequence using double-vector motion compensation  

Microsoft Academic Search

This paper proposes a motion compensation (MC) algorithm for robust transmission of video sequence, called the double-vector motion compensation (DMC). In the DMC, each block B in a frame is predicted from the weighted superposition of two blocks in the previous two frames, using two motion vectors. Therefore, when one of these two blocks is corrupted during the transmission, the

Chang-su Kim; Rin-chul Kim; Sang-Uk Lee

2001-01-01

191

Springback Prediction, Compensation and Correlation for Automotive Stamping  

SciTech Connect

To reduce weight and increase fuel efficiency and safety, more and more automotive sheet stamping parts are being made of aluminum and high strength steels. Forming of such materials encounters not just reduced formability but also dimensional quality problems. Springback prediction accuracy and compensation effectiveness have been the major challenge to die development, construction and tryout. In this paper, the factors that affect the accuracy of springback prediction are discussed, which includes the effect of material models, the selection of element size, and the contact algorithms. Springback predictions of several automotive aluminum and high strength panels are compared with measurement data. The examples show that the prediction correlates with measurement data in both springback trend and magnitude. The effect of springback on final product can be reduced or eliminated through process control and die face compensation. The process control method involves finding the root causes of springback and eliminating them through process modification. The geometrical compensation of die surface is a direct way to eliminate the springback effect. The global scaling compensation method is normally limited to parts with relatively small springback. For large springback and twisting, a new approach is discussed, which takes into account of the effect of deformation and springback history. The compensation is achieved iteratively by solving a system of non-linear equations. Production dies were cut to the compensated surface, which shows that the die compensation is an efficient way to reduce springback-induced geometry deviation.

Xu Siguang; Zhao Kunmin; Lanker, Terry; Zhang, Jimmy; Wang, C.T. [General Motors Corp., Manufacturing Engineering, Die Center, 2000 Centerpoint, Pontiac, MI 48341 (United States)

2005-08-05

192

Reticle specific compensations to meet production overlay requirements for 64 MB and beyond  

NASA Astrophysics Data System (ADS)

A novel technology has been developed whereby a database of reticle specific compensation can be utilized to correct for magnification, rotation, and translational reticle manufacturing errors. Whenever a given reticle is loaded into the stepper, a reticle barcode defining that specific reticle is read. This barcode is associated with a set of reticle specific compensations that are automatically applied during the execution of a production batch. Reticle compensations can be either empirically determined or taken from reticle manufacturing information. Algorithms have been developed which determine reticle specific compensations based on either the manufacturing data or empirically determined data. This data is easily entered into a database allowing any stepper to access reticle compensation information for any reticle. This paper discusses the procedures involved in determining and implementing reticle specific compensations and presents production overlay data indicating overlay performance with and without reticle compensations.

Rogoff, Richard; Hong, Syi-Sying; Schramm, Doug; Espin, Greg

1994-05-01

193

Altitude compensating nozzle evaluation  

NASA Astrophysics Data System (ADS)

Typically, the nozzle area ratio selected for booster applications is a compromise between optimum performance at lift off and optimum performance at altitude. If nozzle area ratio could be tailored for different altitudes, without significant weight increase, vehicle payload performance can be enhanced. This is particularly true for single-stage-to-orbit (SSTO) applications where the nozzle must operate both at sea level and in space. For conventional bell nozzles, altitude compensation is accomplished most effectively by varying the exit areas of the nozzle during ascent. There are two fundamental approaches to varying nozzle exit area. The first is to physically retract the aft skirt of the nozzle allowing operation at the truncated exit area; the skirt is then deployed to allow full nozzle expansion at altitude. The second approach is to design a fixed geometry nozzle to the full and final area ratio and to induce controlled and stable separation at reduced 'effective' exit areas inside the nozzle. This separation is controlled by allowing passive inflow of ambient air. As altitude increases the vent will be closed to prevent outflow of combustion products and to support expansion to a larger effective exit area. This paper summarizes the proof-of-concept evaluation and testing of a passively ventilated altitude compensating nozzle (ACN) concept. The scheme was tested on a modified RL10 under Air Force contract F04611-87-C-0069 in August 1990. This data complements an earlier Air Force ACN activity completed in the early 1970's, under Air Force contract F04611-68-C-0002. In this program the XLR-129 demonstrated significant altitude compensation performance for a two-position translating skirt.

Parsley, R. C.; Vanstelle, Kenneth J.

1992-02-01

194

Atmospheric turbulence mitigation in free space optical communication systems with retro-modulators  

NASA Astrophysics Data System (ADS)

After a brief description of the Free Space Optical communication systems that has been developed for both direct mode and retro mode and which are used by the Naval Research Laboratory for their research on modulating retro-reflectors, this paper presents the implementation of an efficient cone-tracking algorithm for the optimization of the beam pointing in retro-mode links. It is shown how the algorithm can be augmented in order to support the same function in direct-mode links. Furthermore it is shown how this cone-tracking technique, implemented initially to compensate for the system misalignment and the slow drifts related to temperature or remote distance changes, can be used to characterize the beam wander in the far field. The results of a beam wander measurement experiment are then discussed. These results led to developing a multi-dithering adaptive optics algorithm to mitigate the effect of atmospheric turbulence in a retro-mode link. This algorithm works by optimizing the power coupled into the MRR and therefore reducing the fluctuations of the power reflected back to the Interrogator. This algorithm can be thought of as an extension of the cone-tracking technique to higher order aberrations. Finally, results are presented of a proof of concept laboratory experiment of this single-metric multi-dithering modal AO algorithm applied to the coupling into a single mode fiber. The results show the successful convergence of the simultaneous compensation of six low order aberrations. The conclusion is that using faster hardware these encouraging results could eventually lead to a significant reduction of the power fluctuation induced by the atmospheric turbulence in a FSO retro-mode link.

Saint Georges, Eric

195

Defocus compensation system of long focal aerial camera based on auto-collimation  

NASA Astrophysics Data System (ADS)

Nowadays, novel aerial reconnaissance camera emphasizes on the shooting performance in high altitude or in long distance of oblique photography. In order to obtain the larger scale pictures which are easier for image interpretation, we need the camera has long focal length. But long focal length camera is easier to be influenced by environmental condition and lead to great change of lens' back focus which can result in the lens' resolution decreased greatly. So, we should do precise defocusing compensation to long focal aerial camera system. In order to realize defocusing compensation, a defocusing compensation system based on autocollimation is designed. Firstly, the reason which can lead to long focal camera's defocusing was discussed, then the factors such as changes of atmospheric pressure and temperature and oblique photographic distance were pointed out, and mathematical equation which could compute camera's defocusing amount was presented. Secondly, after camera's defocusing was analyzed, electro-optical autocollimation of higher automation and intelligent was adopted in the system. Before shooting , focal surface was located by electro-optical autocollimation focal detection mechanism, the data of airplane's height was imported through electronic control system. Defocusing amount was corrected by computing defocusing amount and the signal was send to focusing control motor. And an efficient improved mountain climb-searching algorithm was adopted for focal surface locating in the correction process. When confirming the direction of curve, the improved algorithm considered both twice focusing results and four points. If four points continue raised, the curve would be confirmed as rising direction. On the other hand, if four points continue decreased, the curve would be confirmed as decrease direction. In this way, we could avoid the local peak value appeared in two focusing steps. The defocusing compensation system consists of optical component and precise control system and precise driver component. Based on FPGA hardware system, hardware function is realized by VHDL. It has been using on some kinds of long focal CCD cameras and film cameras. It not only has good dimensional stability and structural stability in harsh environment, but also has ability of focal surface precision detection and accurate focusing.

Zhang, Yu-Ye; Zhao, Yu-Liang; Xu, Zhao-Lin

2010-05-01

196

Employee Compensation in Entrepreneurial Companies  

Microsoft Academic Search

Despite the central role played by human capital in entrepreneurship, little is known about how employees in entrepreneurial firms are compensated and incentivized. We address this gap in the literature by studying 18,935 non-CEO compensation contracts across 1,809 privately-held venture-backed companies. Our key finding is that employee compensation varies with the degree to which VCs versus founders control the business.

Ola Bengtsson; John R. M. Hand

2012-01-01

197

Executive Compensation in American Unions  

Microsoft Academic Search

[Excerpt] Studying compensation in the non-profit sector is difficult. In non-profit organizations, it is not always clear what the objectives of the organization are and, therefore, perhaps even more difficult to consider how to compensate managers. This paper investigates the determinants of executive compensation of leaders of American labor unions. We use panel data on more than 75,000 organization-years of

Kevin F Hallock; Felice Klein

2009-01-01

198

Hysteresis modelling and compensation for smart sensors and actuators  

NASA Astrophysics Data System (ADS)

The paper outlines the basic features concerning the design of 'embedded' control and compensation algorithms suitable to be employed in smart sensors and actuators, for real time applications. The stringent specifications in such devices require suitable compensation algorithms that can be implemented in cheap and low performance computation units (such as commercial micro-controllers). This paper, starting from a comprehensive analysis of the solutions proposed in recent years for such a task, shows how the capability to describe the behavior of materials having strong magneto-elastic coupling with hysteresis, allows us to employ standard control-based algorithms that are, at the same time, widely effective. The proposed approach is described for actual magnetostrictive actuators.

Visone, C.

2008-11-01

199

Interferometric Microwave Radiometers for High-Resolution Imaging of the Atmosphere Brightness Temperature Based on the Adaptive Capon Signal Processing Algorithm  

Microsoft Academic Search

Passive microwave remote sensing from satellites and ground stations has contributed uniquely, and substantially, to the study of atmospheric chemistry, meteorology, and environmental monitoring. As user requirements are raised, in terms of the accuracy and the spatial resolution, a mechanically scanning radiometer, with a real aperture, becomes impractical due to the requirement for a very large antenna size. However, an

Hyuk Park; Junho Choi; Vladimir Katkovnik; Yonghoon Kim

2004-01-01

200

OCT skin image enhancement through attenuation compensation.  

PubMed

The enhancement of optical coherence tomography (OCT) skin images can help dermatologists investigate the morphologic information of the images more effectively. In this paper, we propose an enhancement algorithm with the stages that includes speckle reduction, skin layer detection, and attenuation compensation. A weighted median filter is designed to reduce the level of speckle while preserving the contrast. A novel skin layer detection technique is then applied to outline the main skin layers: stratum corneum, epidermis, and dermis. The skin layer detection algorithm does not make any assumption about the structure of the skin. A model of the light attenuation is then used to estimate the attenuation coefficient of the stratum corneum, epidermis, and dermis layers. The performance of the algorithm has been evaluated qualitatively based on visual evaluation and quantitatively using two no-reference quality metrics: signal-to-noise ratio and contrast-to-noise ratio. The enhancement algorithm is tested on 35 different skin OCT images, which show significant improvements in the quality of the images, especially in the structures at deeper levels. PMID:22858930

Hojjatoleslami, Ali; Avanaki, Mohammad R N

2012-07-20

201

Temperature compensated photovoltaic array  

DOEpatents

A temperature compensated photovoltaic module comprises a series of solar cells having a thermally activated switch connected in parallel with several of the cells. The photovoltaic module is adapted to charge conventional batteries having a temperature coefficient differing from the temperature coefficient of the module. The calibration temperatures of the switches are chosen whereby the colder the ambient temperature for the module, the more switches that are on and form a closed circuit to short the associated solar cells. By shorting some of the solar cells as the ambient temperature decreases, the battery being charged by the module is not excessively overcharged at lower temperatures. PV module is an integrated solution that is reliable and inexpensive. 2 figs.

Mosher, D.M.

1997-11-18

202

Worker's Compensation for Musicians.  

PubMed

Kudos to Ruth L. Chimenti et al. and MPPA editor Ralph Manchester for their excellent and complementary contributions to the literature regarding performing arts and worker's compensation (WC). Chimenti et al. addressed the issue of why WC is underutilized by professional orchestral musicians. They conducted a survey whose n = 261, with 243 musicians reporting injuries. The survey posits 7 possible reasons for not filing WC claims, plus the option of providing an "other" response. The authors did a good job choosing possible reasons, since all 7 received significant responses. I would offer one "other" reason WC claims are not filed. Such claims are often denied and often taken to court. [Reply is attached.]. PMID:24013289

Lubet, Alex; Chimenti, Ruth L

2013-09-01

203

Adaptive compensation of discrete noise and vibration components  

NASA Astrophysics Data System (ADS)

A multichannel adaptive system for compensation of discrete noise and vibration components excited in a structure or a medium by several periodic mechanisms (e.g., engines, diesels, or turbogenerators) is examined. An iterative algorithm with the highest possible response speed and practically independent of the spatial dimensions of the system and of the number of discrete components is developed to control the system. Experimental results are presented, and it is shown that, in actual operating conditions, the compensation value is 20-25 dB for all discrete components simultaneously.

Liubashevskii, G. S.; Orlov, A. I.; Tartakovskii, B. D.

1992-06-01

204

GIFTS SM EDU Level 1B algorithms  

NASA Astrophysics Data System (ADS)

The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) Sensor Module (SM) Engineering Demonstration Unit (EDU) is a high resolution spectral imager designed to measure infrared (IR) radiances using a Fourier transform spectrometer (FTS). The GIFTS instrument employs three focal plane arrays (FPAs), which gather measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. This paper describes the GIFTS SM EDU Level 1B algorithms involved in the calibration. The GIFTS Level 1B calibration procedures can be subdivided into four blocks. In the first block, the measured raw interferograms are first corrected for the detector nonlinearity distortion, followed by the complex filtering and decimation procedure. In the second block, a phase correction algorithm is applied to the filtered and decimated complex interferograms. The resulting imaginary part of the spectrum contains only the noise component of the uncorrected spectrum. Additional random noise reduction can be accomplished by applying a spectral smoothing routine to the phase-corrected spectrum. The phase correction and spectral smoothing operations are performed on a set of interferogram scans for both ambient and hot blackbody references. To continue with the calibration, we compute the spectral responsivity based on the previous results, from which, the calibrated ambient blackbody (ABB), hot blackbody (HBB), and scene spectra can be obtained. We now can estimate the noise equivalent spectral radiance (NESR) from the calibrated ABB and HBB spectra. The correction schemes that compensate for the fore-optics offsets and off-axis effects are also implemented. In the third block, we developed an efficient method of generating pixel performance assessments. In addition, a random pixel selection scheme is designed based on the pixel performance evaluation. Finally, in the fourth block, the single pixel algorithms are applied to the entire FPA.

Tian, Jialin; Gazarik, Michael J.; Reisse, Robert A.; Johnson, David G.

2007-10-01

205

Compensation: The Impact of Policy.  

ERIC Educational Resources Information Center

Complexity of employee compensation policy is examined as it applies to colleges and universities. It is argued that sound compensation policy helps the institution attract and retain qualified, skilled employees. New approaches that shift the focus from job to employee are outlined, and their implications for institutions of higher education are…

Morrell, Louis R.

1994-01-01

206

Changing Conceptions of Employee Compensation  

ERIC Educational Resources Information Center

This paper reviews and discusses many differing forms of incentive compensation systems that are being used in today's organizations. The review traces the roots of bonus compensation from individual piece-work plans through the adoption of organization-wide gain sharing plans to the growing recognition of open-book management. Reasons for the…

Dixon, Mark R.; Hayes, Linda J.

2004-01-01

207

Share Repurchases and Employee Compensation  

Microsoft Academic Search

This paper focuses on the agency problem derived from the con‡ict of interest between employees and shareholders. I show that if employees are compensated with restricted stock or stock options, shareholders may engage in opportunistic share repurchases. Equityholders have an incentive to buy back stock after employment contracts have been signed because repurchases increase compensation sensitivity to …rm cash ‡ows

Ilona Babenko

2005-01-01

208

Executive compensation and dividend policy  

Microsoft Academic Search

This study examines the use of dividend provisions in executive compensation contracts to influence dividend policy. A sample is constructed with the largest companies in the oil and gas, defense\\/aerospace and food processing industries, where dividend-related agency costs are expected to be high. The results indicate that the existence of a dividend incentive in the compensation plan is positively associated

Lourdes Ferreira White

1996-01-01

209

Negotiating a fair compensation package.  

PubMed

At the end of the day, compensation packages must be fair for both you and your employer. Employers should conduct an economic analysis to determine what they can afford to offer and calculate the economic return that they should rightfully receive. Understanding the employer's side of the equation is equally important in developing a win/win compensation package for yourself. PMID:16001883

Snyder, Thomas L

2005-01-01

210

Executive Compensation: Six Questions that Need Answering  

Microsoft Academic Search

In this article, we focus on how recent research advances can be used to address the following six questions: (1) How much does executive compensation cost the firm? (2) How much is executive compensation worth to the recipient? (3) How well does executive compensation work? (4) What are the effects of executive compensation? (5) How much executive compensation is enough?

John M. Abowd; David S. Kaplan

1999-01-01

211

Workers' compensation law: an overview.  

PubMed

1. The workers' compensation system provides benefits to workers who are injured or made ill in the course of employment or their dependents regardless of fault. 2. The current workers' compensation laws benefit both the employer and the employee; however, workers' compensation is an exclusive remedy which bars recovery through a negligence lawsuit. 3. Workers' compensation regulations interact with other federal statutes such as the Americans With Disabilities Act and the Family Medical Leave Act. 4. Workers' compensation covers occupational injuries and occupational diseases, which may include cumulative trauma and mental stress claims. Nurses may be instrumental in evaluating and planning for an injured employee's return to work and occasionally in detecting fraudulent claims. PMID:7945592

Yorker, B

1994-09-01

212

Water Vapour GNSS Based Tomography For Wet Delay Compensation In In-SAR Applications  

NASA Astrophysics Data System (ADS)

One of the most challenging exploitation of GNSS signals for meteorological applications is the retrieval of Water Vapor tridimensional distribution. The real-time (or quasi real-time) knowledge of such distributions could be very useful for several applications: from operative meteorology to atmospheric modeling, or for atmospheric compensation purposes applied for example to SAR or In-SAR observations, in order to improve land remote sensing. In the framework of the European Space Agency project METAWAVE (Mitigation of Electromagnetic Transmission errors induced by Atmospheric Water Vapor Effects), several techniques were investigated in order to find out an In-SAR data compensation strategy for the propagation delay effects due to Water Vapour. Thanks to METAWAVE, a quite dense GPS network (7 dual frequency GPS receivers) was deployed over COMO area and was used for an extensive measurement campaign. The acquired L1 and L2 carrier phase observations were processed in terms of hourly averaged Zenith Wet Delays. These vertical information were mapped along the correspondent line of sights (by up-sampling at 30 second sample times the 15 minutes GPS satellites positions obtained from IGS files) and inverted using a tomographic procedure. The used algorithm performs a first reconstruction (namely, the tomographic pre-processing) based on generalized inversion mechanisms, in order to define a low resolution first guess for the next step. This second step inverts GPS observables using a more refined algebraic tomographic reconstruction algorithm, to improve both vertical and horizontal resolution. Results of this inversion are Wet Refractivity maps distributed over an area of 16 km x 20 km (x 10 km height) around the COMO city, characterized by horizontal resolutions varying from 2 km to 4 km and vertical resolution of 500m. This contribution deals with the description of the results obtained evaluating Water Vapour path delays from such Wet Refractivity maps. Integrals of Wet Refractivity along given line-of-sights were validated considering a self-consistency approach. Sensitivity of final results to the observation geometry will be discussed and improvements related to the ingestion of low elevation observations will be analyzed. In addition remarks about the reconstruction error in function of distance from a certain reference station and of station height will be highlighted. Finally, interesting results related to the use of high-rate real slant Delays as input to the tomography will be shown. The authors are grateful to ESA for supporting this work in the framework of the project METAWAVE, to the project PIs Prof. N. Pierdicca and Prof. F. Rocca and to G. Venuti and Prof. F. Sansò (Politecnico di Milano) for the COMO GPS network data acquisition and data processing.

Notarpietro, Riccardo; Cucca, Manuela; Perona, Giovanni

2010-05-01

213

Multivariable adaptive algorithms for reconfigurable flight control  

Microsoft Academic Search

The application of multivariable adaptive control techniques to flight control reconfiguration is considered. The objective is to redesign automatically flight control laws to compensate for actuator failures or surface damage. Three adaptive algorithms for multivariable model reference control are compared. The availability of state measurements in this application leads to relatively simple algorithms. The respective advantages and disadvantages of the

Marc Bodson; Joseph E. Groszkiewicz

1997-01-01

214

Compensated pulsed alternator  

DOEpatents

This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the field as the armature coil rotates. The armature coil comprises a plurality of power generating conductors mounted on the rotor. The alternator may also include a stationary or counterrotating compensating coil to increase the output voltage thereof and to reduce the internal impedance of the alternator at the moment of peak outout. As the machine voltage rises sinusoidally, an external trigger switch is adapted to be closed at the appropriate time to create the desired output current from said alternator to an external load circuit, and as the output current passes through zero a self-commutating effect is provided to allow the switch to disconnect the generator from the external circuit.

Weldon, William F. (Austin, TX); Driga, Mircea D. (Austin, TX); Woodson, Herbert H. (Austin, TX)

1980-01-01

215

75 FR 22679 - Sound Incentive Compensation Guidance  

Federal Register 2010, 2011, 2012, 2013

...Office of Thrift Supervision Sound Incentive Compensation Guidance...collection; c. Ways to enhance the quality, utility, and clarity of the...collection. Title of Proposal: Sound Incentive Compensation Guidance...consistent with the Principles for Sound Compensation Practices...

2010-04-29

216

75 FR 53023 - Sound Incentive Compensation Guidance  

Federal Register 2010, 2011, 2012, 2013

...Office of Thrift Supervision Sound Incentive Compensation Guidance...collection; c. Ways to enhance the quality, utility, and clarity of the...collection. Title of Proposal: Sound Incentive Compensation Guidance...consistent with the Principles for Sound Compensation Practices...

2010-08-30

217

33 CFR 136.211 - Compensation allowable.  

Code of Federal Regulations, 2013 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims § 136.211 Compensation allowable. (a) The amount of compensation...

2013-07-01

218

33 CFR 136.229 - Compensation allowable.  

Code of Federal Regulations, 2013 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims § 136.229 Compensation allowable. The amount of compensation allowable is...

2013-07-01

219

Radiation compensator for gas sensors  

SciTech Connect

A compensator device for providing direct and automatic correction of electrolytic gas sensor performance anomalies caused by exposure of the sensor to high levels of ionizing radiation. The compensator device, which compensates for changes in sensor performance while operating in a radiation field, provides an electromotive force which directly cancels that portion of the electromotive force developed by the active electrolytic gas sensor produced by the radiation rather than by presence of the gas. The compensating device is constructed in the same configuration as the active electrolytic sensor with the exception that the sensing electrode of the compensating device is not exposed to the sample gas environment. The sensor and compensator device are connected in a circuit such that their electromotive forces oppose one another, thereby determining the difference between the signals so that the radiation induced component is removed, and only the signal representing the partial pressure of gas remains. An alternate embodiment wherein the compensating signal is generated within the same sensor housing by the addition of one more electrode is also disclosed.

Rudek, F.

1985-02-05

220

The use of MODIS 250 m bands to improve the MODIS 1 km ocean color atmospheric correction algorithm in turbid water  

NASA Astrophysics Data System (ADS)

"Clear water" is a scale-dependent concept, so it is more likely to successfully find the "clear water" from images with smaller scale than that with larger scale data. In this study, an optimal spectral relationship of moderate-resolution imaging spectroradiometer (MODIS) 250 m and 1 km resolution data at near-infrared bands (OSRLM) is constructed for converting pseudo "clear water" reflectance at 859 nm to those at 748 and 869 nm. According to scale effects, the satellite-observed pseudo "clear water" reflectance is greater than 5.18%, larger than that derived from OSRLM model. An atmospheric correction model for MODIS 1km data using pseudo "clear water" reflectance of MODIS 250 m data (ACMM) was developed for improving the performance of traditional "clear water" atmospheric correction model (CWAC). The model validation results indicate that ACMM model has a better performance than CWAC model. By comparison, the uncertainty decreases by 19.18% in the use of ACMM model over CWAC model for deriving water-leaving reflectance in Taihu Lake, China. This uncertainty is significantly reduced in water-leaving reflectance estimation due to partial removal of scale effects on "clear water". These findings imply that satellite-derived aerosol scattering contribution at smaller scale usually has a better performance than that at larger scale.

Chen, Jun; Quan, Wenting; Wen, Zhenhe; Cui, Tingwei

2013-05-01

221

7 CFR 301.74-5 - Compensation.  

Code of Federal Regulations, 2010 CFR

... (1) Owners of commercial stone fruit orchards. Owners of commercial stone fruit orchards are eligible to receive compensation...APHIS). (i) Direct marketers. Orchard owners eligible for compensation...

2010-01-01

222

7 CFR 301.74-5 - Compensation.  

Code of Federal Regulations, 2010 CFR

... (1) Owners of commercial stone fruit orchards. Owners of commercial stone fruit orchards are eligible to receive compensation...APHIS). (i) Direct marketers. Orchard owners eligible for compensation...

2009-01-01

223

Wavefront aberration compensation of projection lens using clocking lens elements.  

PubMed

For extremely high-performance lithographic lenses, the edge level accuracy of the manufacturing process and multicompensation strategies must be applied. Element clocking can be effectively used to compensate for the low-order figure errors of the elements. Considering that commercial optical software is usually incapable of obtaining good convergence for clocking optimization, this paper proposes a mathematical model of a lithographic lens containing the errors of a surface figure, after which a clocking optimization algorithm is programmed. A clocking optimization instance proving that the clocking optimization algorithm is capable of finding the optimized angle of elements and that clocking is an effective compensation strategy. The calculated accuracy of the proposed mathematic model was found to be acceptable for clocking optimization. PMID:23913057

Liu, Chunlai; Huang, Wei; Shi, Zhenguang; Xu, Weicai

2013-08-01

224

Temperature Compensated Piezoelectric Oxide Materials.  

National Technical Information Service (NTIS)

In order to search for new temperature compensated materials for surface acoustic wave (SAW) devices with low ultrasonic attenuation and high electromechanical coupling, the following investigations were carried out: (1) Crystal growth for lead potassium ...

G. R. Barsch K. E. Spear

1979-01-01

225

Host State Incentives and Compensation:.  

National Technical Information Service (NTIS)

After reviewing several options for selecting a host state, the Commission elected to proceed with anoption that builds upon developing grass-roots acceptance and support. To foster such support the Commission has adopted an incentives and compensation pa...

P. Schneider

1986-01-01

226

Fundamentals of compensation and benefits.  

PubMed

The authors discuss the objectives of compensation programs--including direct and indirect forms of reward--and employee motivation. Job descriptions and job evaluations are also explored. PMID:11401793

Diorio, J A; Fallon, L F

227

Changing Conceptions of Employee Compensation  

Microsoft Academic Search

This paper reviews and discusses many differing forms of incentive compensation systems that are being used in today's organizations. The review traces the roots of bonus compensation from individual piece-work plans through the adoption of organization-wide gainsharing plans to the growing recognition of open-book management. Reasons for the shift in units of analysis from the individual employee to the work

Mark R. Dixon; Linda J. Hayes; Jack Stack

2004-01-01

228

National Compensation Survey Home Page  

NSDL National Science Digital Library

The Bureau of Labor Statistics (BLS) posts this publication online, with sections downloadable as .pdf files. The release, the National Compensation Survey, is a redesign of BLS' compensation statistics to reflect the workplace of the 21st century. From the main page, users can access the full .pdf-format text of the survey results as well as a summary, and a wealth of other related sites and documents.

229

Real-time smoke rendering using compensated ray marching  

Microsoft Academic Search

We present a real-time algorithm called compensated ray marching for rendering of smoke under dynamic low-frequency environment lighting. Our approach is based on a decomposition of the input smoke animation, represented as a sequence of volumetric density fields, into a set of radial basis functions (RBFs) and a sequence of residual fields. From this low-frequency RBF approximation of density fields,

Kun ZhouZhong; Zhong Ren; Stephen Lin; Hujun Bao; Baining Guo; Heung-yeung Shum

2008-01-01

230

Coding of digital TV by motion-compensated Gabor decomposition  

NASA Astrophysics Data System (ADS)

The block-based motion estimation algorithm we have previously proposed possesses the advantages of a high estimation accuracy and a good prediction performance. It can efficiently be employed in a motion-compensated DPCM coder to minimize the data bits for the transmission of prediction errors. However, the motion overhead data rate, although it has been compressed dramatically by the coding method we proposed, is still too high to work at very low bit-

Dufaux, Frederic; Ebrahimi, Touradj; Geurtz, Alexander M.; Kunt, Murat

1991-12-01

231

Dosimetric verification of compensated beams using radiographic film  

PubMed Central

Introduction External photon beam modulation using compensators in order to achieve a desired dose distribution when brachytherapy treatment is followed by external beam radiation is a well-established technique. A compensator modulates the central part of the beam, and the dose beneath the thickest part of the compensator is delivered mostly by scattered, low energy photons. A two-dimensional detector with a good spatial resolution is needed for the verification of those beams. In this work, the influence of different types of detectors on the measured modulated dose distributions was examined. Materials and methods Dosimetric verification was performed using X-Omat V, Eastman Kodak radiographic films at different depths in a solid water phantom. The film measurements were compared with those made by ionization chambers. Photon beams were also modelled using EGSnrc Monte Carlo algorithm to explain the measured results. Results Monte Carlo calculated over-response of the film under the thickest part of the compensator was over 15%, which was confirmed by measurements. The magnitude of over-response could be associated with changes in the spectra of photon energy in the beam. Conclusions The radiographic film can be used for the dosimetry of compensated high energy photon beams, with limitations in volumes where photon spectra are hardly degraded.

Jurkovic, Slaven; Zauhar, Gordana; Faj, Dario; Radojcic, Deni Smilovic; Svabic, Manda; Kasabasic, Mladen; Diklic, Ana

2011-01-01

232

Noise Robust Motion Refinement for Motion Compensated Noise Reduction  

NASA Astrophysics Data System (ADS)

A motion refinement algorithm is proposed to enhance motion compensated noise reduction (MCNR) efficiency. Instead of the vector with minimum distortion, the vector with minimum distance from motion vectors of neighboring blocks is selected as the best motion vector among vectors which have distortion values within the range set by noise level. This motion refinement finds more accurate motion vectors in the noisy sequences. The MCNR with the proposed algorithm maintains the details of an image sequence very well without blurring and joggling. And it achieves 10% bit-usage reduction or 0.5dB objective quality enhancement in subsequent video coding.

Kim, Jong-Sun; Kim, Lee-Sup

233

Measurements of atmospheric parameters using the SOR atmospheric monitor  

NASA Astrophysics Data System (ADS)

We discuss the SOR Atmospheric Monitor's (SAM's) algorithms for estimating a number of atmospheric parameters from Shack-Hartmann wave front sensor measurements. In addition to the previously reported Fried parameter work, we report on estimates of Greenwood frequency and isoplanatic angle. We also report on a few months of statistics of these parameters at Kirtland AFB.

Spillar, Earl J.

2011-05-01

234

Error analysis for a temperature and emissivity retrieval algorithm for hyperspectral imaging data  

NASA Astrophysics Data System (ADS)

In the hyperspectral thermal data analysis temperature-emissivity separation has the same function as reflectance retrieval in the visible and shortwave infrared. The problem however is more complicated since in the thermal the surface emits and reflects radiation. The measured radiance is a function of the materials' surface emissivity and temperature, reflected down welling radiance (clear sky, clouds environment) and the path radiance (temperature and gas (e.g. water vapor, ozone) profiles). The current implementation of the Automatic Retrieval of Temperature and EMIssivity using Spectral Smoothness (ARTEMISS) uses look-up-tables (LUT) to infer the best fitting atmosphere which results in the smallest residual to the In-Scene Atmospheric Compensation (ISAC) estimated transmission. Over last few years we have developed an end-to-end simulation of the hyper spectral exploitation process by generating synthetic data to simulate datasets with "known" ground truth, modeling propagation through the atmosphere, adding sensor effects (telescope, detector, read-out electronics), radiometric and spectral calibration, and test the temperature emissivity separation algorithm. We will present an error analysis where we shifted the band centers, varied the full-width half maximum (FWHM) of the spectral response function, changed the spectral resolution, added noise and varied the atmospheric model. We will also discuss a general method to retrieve the spectral smile as a function of wavelength and the FWHM from hyperspectral data with only approximate spectral calibration. We found that our algorithm has trouble finding a unique solution when the watervapor exceeds about 3 g/cm2 and will discuss remedies for this situation. To speedup the LUT generation we have developed fast and robust initial atmospheric parameter estimators (water vapor, ozone, near surface atmospheric layer temperature) based on channel ratios and brightness temperatures in atmospheric absorption regions for the LWIR.

Borel, Christoph

2007-04-01

235

20 CFR 10.401 - When and how is compensation for total disability paid?  

Code of Federal Regulations, 2013 CFR

...OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL EMPLOYEES' COMPENSATION ACT, AS AMENDED Compensation and Related Benefits Compensation...

2013-04-01

236

20 CFR 10.403 - When and how is compensation for partial disability paid?  

Code of Federal Regulations, 2013 CFR

...OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL EMPLOYEES' COMPENSATION ACT, AS AMENDED Compensation and Related Benefits Compensation...

2013-04-01

237

Comparison of motion-compensated reconstruction with FBP and BPF for circular X-ray tomography: A simulation study  

Microsoft Academic Search

We present two new approximate variants of motion-compensated 3D back-projection filtration (MC-BPF) algorithms for circular cone-beam X-ray tomography in divergent beam geometry. The first one uses differentiation in a single projection (SD), while the second one is based on the Katsevich-type differentiation (KD) involving two neighboring projections. The BPF-type algorithms are compared to an approximate 3D motion-compensated filtered back-projection (MC-FDK)

Dirk Schafer; Michael Grass

2011-01-01

238

Executive Compensation in the Life Insurance Industry  

Microsoft Academic Search

Alternative theories imply differential compensation levels between executives of mutual and stock insurance companies. Evidence from the life insurance industry indicates (1) the compensation of mutual executives is lower than that of stock executives, (2) the compensation of mutual-subsidiary executives is lower than that of stock-subsidiary executives, and (3) the compensation of mutual executives is less responsive to firm performance

David Mayers

1992-01-01

239

Reactive power compensation for wind power plants  

Microsoft Academic Search

This technical paper provides the basic guidelines for the application of reactive compensation systems to be used as part of a wind power plant. A brief history of wind plant reactive compensation system is discussed, then the fundamental needs of why reactive compensation is required. The paper will then provide some alternatives for reactive compensation, how to size the reactive

E. H. Camm; M. R. Behnke; O. Bolado; M. Bollen; M. Bradt; C. Brooks; W. Dilling; M. Edds; W. J. Hejdak; D. Houseman; S. Klein; F. Li; J. Li; P. Maibach; T. Nicolai; J. Patino; S. V. Pasupulati; N. Samaan; S. Saylors; T. Siebert; T. Smith; M. Starke; R. Walling

2009-01-01

240

Jovian atmospheres  

SciTech Connect

A conference on the atmosphere of Jupiter produced papers in the areas of thermal and ortho-para hydrogen structure, clouds and chemistry, atmospheric structure, global dynamics, synoptic features and processes, atmospheric dynamics, and future spaceflight opportunities. A session on the atmospheres of Uranus and Neptune was included, and the atmosphere of Saturn was discussed in several papers.

Allison, M.; Travis, L.D.

1986-10-01

241

Asymmetric information and executive compensation contract management  

Microsoft Academic Search

In this paper, we analyze the function of executive compensation, as well as the effect of asymmetric information on the effectiveness of compensation contract, using the theory of information asymmetry in information economics. We also put forward measures to improve the effectiveness of compensation contract. Keywords—information asymmetry;compensation contract; compensation-performance sensitivity Information asymmetry can be classified from two perspectives:firstly,the occurred time

Shengli Zhang

2011-01-01

242

EMITTANCE COMPENSATION FOR MAGNETIZED BEAMS  

SciTech Connect

Emittance compensation is a well established technique for minimizing the emittance of an electron beam from a RF photo-cathode gun. Longitudinal slices of a bunch have a small emittance, but due to the longitudinal charge distribution of the bunch and time dependent RF fields they are not focused in the same way, so that the direction of their phase ellipses diverges in phase space and the projected emittance is much larger. Emittance compensation reverses the divergence. At the location where the slopes of the phase ellipses coincide the beam is accelerated, so that the space charge forces are reduced. A recipe for emittance compensation is given in. For magnetized beams (where the angular momentum is non-zero) such emittance compensation is not sufficient because variations in the slice radius lead to variations in the angular speed and therefore to an increase of emittance in the rotating game. We describe a method and tools for a compensation that includes the beam magnetization.

KEWISCH,J.; CHANG, X.

2007-06-25

243

Static synchronous series compensator: A solid-state approach to the series compensation of transmission lines  

Microsoft Academic Search

This paper describes an active approach to series line compensation, in which a synchronous voltage source, implemented by a gate turn-off thyristor (GTO) based voltage-sourced inverter, is used to provide controllable series compensation. This compensator, called Static Synchronous Series Compensator (SSSC), can provide controllable compensating voltage over an identical capacitive and inductive range, independently of the magnitude of the line

L. Gyugyi; C. D. Schauder; K. K. Sen

1997-01-01

244

Improved inverted decoupling control using dead-time compensator for MIMO processes  

Microsoft Academic Search

This paper presents an improved inverted decoupling control strategy using dead-time compensator (DTC) for multi-input multi-output (MIMO) processes when a first order plus dead-time (FOPDT) model of the process is considered. By implementing analytic operation and a definite search algorithm, an effective DTC matrix can be attained. Then the conventional inverted decoupling can be applied to the compensated processes, and

Luo Yunhui; Liu Hongbo; Jia Lei

2010-01-01

245

Rate-Distortion Optimized Motion-Compensated Prediction for Packet Loss Resilient Video Coding  

Microsoft Academic Search

A rate-distortion optimized motion-compensated prediction method for robust video coding is proposed. Contrasting methods from the conventional literature, the proposed approach uses the expected reconstructed distortion after transmission, instead of the displaced frame difference in motion estimation. Initially, the end-to-end reconstructed distortion is estimated through a recursive per-pixel estimation algorithm. Then the total bit rate for motion-compensated encoding is predicted

Shuai Wan; Ebroul Izquierdo

2007-01-01

246

Invertible temporal subband\\/wavelet filter banks with half-pixel-accurate motion compensation  

Microsoft Academic Search

Three-dimensional (3-D) subband\\/wavelet coding with motion compensation has been demonstrated to be an efficient technique for video coding applications in some recent research works. When motion compensation is performed with half-pixel accuracy, images need to be interpolated in both temporal subband analysis and synthesis stages. The resulting subband filter banks developed in these former algorithms were not invertible due to

Shih-ta Hsiang; John W. Woods; Jens-rainer Ohm

2004-01-01

247

Weighted-adaptive motion-compensated frame rate up-conversion  

Microsoft Academic Search

In this paper, we propose a frame rate upconversion algorithm using the weighted-adaptive motion-compensated interpolation (WAMCI) that reduces the block artifacts due to the failure of motion estimation and block-based processing. The proposed method is based on the interpolation scheme by weighted sum of multiple motion-compensated interpolation (MCI) images. Also, in the proposed method, the block artifacts on the block

Sung-Hee Lee; Ohjae Kwon; Rae-Hong Park

2003-01-01

248

Atmospheric turbulence compensation with laser phase shifting interferometry  

Microsoft Academic Search

Laser guide stars with adaptive optics allow astronomical image correction in the absence of a natural guide star. Single guide star systems with a star created in the earth's sodium layer can be used to correct the wavefront in the near infrared spectral regime for 8-m class telescopes. For possible future telescopes of larger sizes, or for correction at shorter

Sebastian Rabien; Frank Eisenhauer; Reinhard Genzel; Richard I. Davies; Thomas Ott

2006-01-01

249

Temperature-compensated chemical reactions  

NASA Astrophysics Data System (ADS)

Circadian rhythms are daily oscillations in behaviors that persist in constant light/dark conditions with periods close to 24h . A striking feature of these rhythms is that their periods remain fairly constant over a wide range of physiological temperatures, a feature called temperature compensation. Although circadian rhythms have been associated with periodic oscillations in mRNA and protein levels, the question of how to construct a network of chemical reactions that is temperature compensated remains unanswered. We discuss a general framework for building such a network.

Rajan, Kanaka; Abbott, L. F.

2007-02-01

250

Relevance of radiation compensation litigation to compensation for toxic exposures  

Microsoft Academic Search

Several recent court decisions add to the growing body of law concerning the responsibility of Government in radiation matters and the quantum of proof needed to show causation between radiation exposures and certain types of cancer and leukemia. The courts have also been addressing a wide range of compensation claims for exposures to toxic chemicals with demonstration of causation being

Glenn E. Schweitzer

1987-01-01

251

Hybrid frequency-time domain Tx and Rx I/Q imbalance compensation for coherent optical OFDM transmission  

NASA Astrophysics Data System (ADS)

A compensation scheme for transmitter (Tx) and receiver (Rx) I/Q imbalance with the interference of carrier frequency offset for CO-OFDM transmission is demonstrated. It has low over-head using only two specific designed symbols for Rx side I/Q imbalance and two for that of Tx side, respectively. Rx compensation is performed in time domain after OFDM frame synchronization and the Tx I/Q imbalance is compensated in frequency domain after channel and phase estimation. The bit error rate (BER) and Q improvement are evaluated experimentally to demonstrate the effectiveness of compensation algorithms. This scheme performs better with the increase of OSNR.

Chen, Simin; Al Amin, Abdullah; Shieh, William

2010-12-01

252

Radial k-t FOCUSS using motion estimation and compensation  

NASA Astrophysics Data System (ADS)

Recently, a model based dynamic imaging algorithm called k-t BLAST/SENSE has drawn significant attentions from MR imaging community due to its improved spatio-temporal resolution for dynamic MR imaging. In our previous work, we proved that k-t BLAST/SENSE can be derived as the first step of FOCal Underdetermined System Solver (FOCUSS) that exploits the sparsity of x-f support. Furthermore, the newly derived algorithm called k-t FOCUSS can be shown optimal from compressed sensing perspective. In this paper, the k-t FOCUSS algorithm is extended to radial trajectory. More specifically, the radial data are transformed to Cartesian domain implicitly during the FOCUSS iterations without explicit gridding to prevent error propagation. Thanks to the implicit gridding that allows fast Fourier transform, we can reduce the computational burden significantly. Additionally, a novel concept of motion estimation and compensation (ME/MC) is proposed to improve the performance of the algorithm significantly. In our ME/MC framework, we additionally obtain one reference sinogram with the full view, then the reference signogram is subtracted from all the radial data. Then, we can apply motion estimation/ motion compensation (ME/MC) to improve the final reconstruction. The experimental results show that our new method can provide very high resolution even from very limited radial data set.

Jung, Hong; Yoo, Jaeheung; Ye, Jong Chul

2008-08-01

253

Compensation of Navajo Uranium Miners  

NSDL National Science Digital Library

This site addresses policy issues of the compensation of Navajo uranium miners. The site provides an annotated index of current issues, legislation, papers and presentations, books, and links that lead to more information on uranium miners. Imbedded links throughout the text lead to related information.

Project, World I.

254

Clarification of Workmen's Compensation Insurance.  

ERIC Educational Resources Information Center

This document attempts to answer questions resulting from the 1972 Michigan Supreme Court Ruling relative to agricultural employees under the Workmen's Compensation Act (WCA). The sections of this paper outline a history of the WCA; employers covered; definition of "regularly employ"; clarification of "thirteen weeks"; employees (minors, partners,…

Shapley, Allen E.

255

More than money. [Employee compensation  

Microsoft Academic Search

Structured wisely, compensation and benefits packages become tactical tools that can unleash the power of utilities' secret weapon - their employees. In fact, in virtually all businesses, people are becoming the raw material of competitive advantage. The reason is this simple: competitive advantage comes from understanding what the market-place wants and then delivering it. And employees are the means through

J. M. Burns; A. D. Fokonas; R. F. Meischeid

2009-01-01

256

Employee Compensation: Research and Practice  

Microsoft Academic Search

[Excerpt] In this chapter, our goal is to define and describe the major decisions that organizations make in managing employee compensation and, based on theory, research, and practice, evaluate what the outcomes of such decisions are likely to be under different conditions. We have made several specific decisions in focusing the review.

Barry A. Gerhart; George T. Milkovich

1991-01-01

257

Can Education Compensate for Society?  

ERIC Educational Resources Information Center

|The extent to which education can compensate for social disadvantage is a matter of political controversy, especially in the context of policies for social mobility. On the one hand, to blame poor achievement on social class or poverty was seen to dodge the professional responsibility of teachers. On the other, the strong correlation between…

Pring, Richard

2011-01-01

258

Issues in Managerial Compensation Research  

Microsoft Academic Search

[Excerpt] Compensation is at the core of any employment exchange (Milkovich & Newman, 1993; Simon, 1951). It is probably the most basic reason people agree to become employees and it serves as a defining characteristic of any employment relationship (March & Simon, 1958). Recently, managers have been bombarded with a profusion of ways to pay employees. There is team-based pay,

Matthew C. Bloom; George T. Milkovich

1995-01-01

259

Managerial Compensation and Capital Structure  

Microsoft Academic Search

We investigate the interaction between financial structure and managerial compensation and show that risky debt affects both the probability of managerial replacement and the manager's wage if he is retained by the firm. Our model yields a rich set of predictions, including the following: (i) The market values of equity and debt decrease if the manager is replaced; moreover, the

Elazar Berkovitch; Ronen Israel; Yossef Spiegel

2000-01-01

260

Unidirectional motion compensated temporal interpolation  

Microsoft Academic Search

Common techniques such as frame repetition or linear interpolation for reconstructing skipped frames in temporally subsampled video sequence tend to introduce undesirable artifacts. A previously proposed technique, motion compensated temporal interpolation (MCTI) can interpolate video frames in the time domain with good image quality at the cost of high computational requirement and substantial memory requirement. In this paper, we propose

Chi-Wah Tang; Oscar C. Au

1997-01-01

261

Behavioral Confirmation and Behavioral Compensation.  

ERIC Educational Resources Information Center

|Individuals interacting with an unfamiliar target person behave according to prior impressions of the target. A perceiver's pre-interaction expectancy can mediate both his and the target person's behavior, resulting in behavioral confirmation or compensation. Male subjects (N=96) participated in dyadic interactions in which one subject…

Ickes, William

262

Strategic Design of Teacher Compensation  

ERIC Educational Resources Information Center

Spurred by the national focus on revitalizing the teacher evaluation and support/development process, as well as the current economic downturn, many school districts are reviewing how teachers are compensated. While a few courageous districts have completely upended current structures, most districts are undertaking changes that leave the most…

Shields, Regis

2012-01-01

263

Synchrony - Cyberknife Respiratory Compensation Technology  

SciTech Connect

Studies of organs in the thorax and abdomen have shown that these organs can move as much as 40 mm due to respiratory motion. Without compensation for this motion during the course of external beam radiation therapy, the dose coverage to target may be compromised. On the other hand, if compensation of this motion is by expansion of the margin around the target, a significant volume of normal tissue may be unnecessarily irradiated. In hypofractionated regimens, the issue of respiratory compensation becomes an important factor and is critical in single-fraction extracranial radiosurgery applications. CyberKnife is an image-guided radiosurgery system that consists of a 6-MV LINAC mounted to a robotic arm coupled through a control loop to a digital diagnostic x-ray imaging system. The robotic arm can point the beam anywhere in space with 6 degrees of freedom, without being constrained to a conventional isocenter. The CyberKnife has been recently upgraded with a real-time respiratory tracking and compensation system called Synchrony. Using external markers in conjunction with diagnostic x-ray images, Synchrony helps guide the robotic arm to move the radiation beam in real time such that the beam always remains aligned with the target. With the aid of Synchrony, the tumor motion can be tracked in three-dimensional space, and the motion-induced dosimetric change to target can be minimized with a limited margin. The working principles, advantages, limitations, and our clinical experience with this new technology will be discussed.

Ozhasoglu, Cihat [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA (United States)], E-mail: ozhasogluc@upmc.edu; Saw, Cheng B.; Chen Hungcheng; Burton, Steven; Komanduri, Krishna; Yue, Ning J.; Huq, Saiful M.; Heron, Dwight E. [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA (United States)

2008-07-01

264

Mutuality, Performance and Executive Compensation  

Microsoft Academic Search

The determinants of CEO compensation within the U.K. Building Society sector are investigated. Using an unbalanced panel data set for the period 1986-90, the authors find only weak support for the existence of a positive performance and CEO remuneration. In contrast, they find age to be an important determinant of CEO pay increases. This finding reinforces the oft noted potential

Hilary Ingham; Steve Thompson

1995-01-01

265

A Cenozoic record of the equatorial Pacific carbonate compensation depth.  

PubMed

Atmospheric carbon dioxide concentrations and climate are regulated on geological timescales by the balance between carbon input from volcanic and metamorphic outgassing and its removal by weathering feedbacks; these feedbacks involve the erosion of silicate rocks and organic-carbon-bearing rocks. The integrated effect of these processes is reflected in the calcium carbonate compensation depth, which is the oceanic depth at which calcium carbonate is dissolved. Here we present a carbonate accumulation record that covers the past 53 million years from a depth transect in the equatorial Pacific Ocean. The carbonate compensation depth tracks long-term ocean cooling, deepening from 3.0-3.5?kilometres during the early Cenozoic (approximately 55?million years ago) to 4.6 kilometres at present, consistent with an overall Cenozoic increase in weathering. We find large superimposed fluctuations in carbonate compensation depth during the middle and late Eocene. Using Earth system models, we identify changes in weathering and the mode of organic-carbon delivery as two key processes to explain these large-scale Eocene fluctuations of the carbonate compensation depth. PMID:22932385

Pälike, Heiko; Lyle, Mitchell W; Nishi, Hiroshi; Raffi, Isabella; Ridgwell, Andy; Gamage, Kusali; Klaus, Adam; Acton, Gary; Anderson, Louise; Backman, Jan; Baldauf, Jack; Beltran, Catherine; Bohaty, Steven M; Bown, Paul; Busch, William; Channell, Jim E T; Chun, Cecily O J; Delaney, Margaret; Dewangan, Pawan; Dunkley Jones, Tom; Edgar, Kirsty M; Evans, Helen; Fitch, Peter; Foster, Gavin L; Gussone, Nikolaus; Hasegawa, Hitoshi; Hathorne, Ed C; Hayashi, Hiroki; Herrle, Jens O; Holbourn, Ann; Hovan, Steve; Hyeong, Kiseong; Iijima, Koichi; Ito, Takashi; Kamikuri, Shin-ichi; Kimoto, Katsunori; Kuroda, Junichiro; Leon-Rodriguez, Lizette; Malinverno, Alberto; Moore, Ted C; Murphy, Brandon H; Murphy, Daniel P; Nakamura, Hideto; Ogane, Kaoru; Ohneiser, Christian; Richter, Carl; Robinson, Rebecca; Rohling, Eelco J; Romero, Oscar; Sawada, Ken; Scher, Howie; Schneider, Leah; Sluijs, Appy; Takata, Hiroyuki; Tian, Jun; Tsujimoto, Akira; Wade, Bridget S; Westerhold, Thomas; Wilkens, Roy; Williams, Trevor; Wilson, Paul A; Yamamoto, Yuhji; Yamamoto, Shinya; Yamazaki, Toshitsugu; Zeebe, Richard E

2012-08-30

266

An investigation of Bjerknes Compensation in the Southern Ocean in the CCSM4  

SciTech Connect

This project aims to understand the relationship between poleward oceanic and atmospheric heat transport in the Southern Ocean by analyzing output from the community Climate System Model Version 4 (CCSM4). In particular, time series of meridional heat transport in both the atmosphere and the ocean are used to study whether variability in ocean heat transport is balanced by opposing changes in atmospheric heat transport, called Bjerknes Compensation. It is shown that the heat storage term in the Southern Ocean has a significant impact on the oceanic heat budget; as a result, no robust coherences between oceanic and atmospheric heat transports could be found at these southern latitudes.

Weijer, Wilbert [Los Alamos National Laboratory; Kinstle, Caroline M. [Los Alamos National Laboratory

2012-08-28

267

Genetic Algorithms  

Microsoft Academic Search

In this chapter we describe the basics of Genetic Algorithms and how they can be used to train Artificial Neural Networks.\\u000a Supervised training of Multilayer Perceptrons for classification problems is considered. We also explain how the Genetic Algorithm\\u000a can be hybridized with other algorithms and present two hybrids between it and two classical algorithms for the neural network\\u000a training: Backpropagation

Enrique Alba; Francisco Chicano

268

Need for a Theory of Military Compensation.  

National Technical Information Service (NTIS)

The author argues that the lack of a coherent articulated theory of military compensation has been a major factor in the failure of past military compensation studies, reviews, and legislative initiatives. He urges that this intellectual void be filled as...

P. K. Ogloblin

1981-01-01

269

Compensation Policies under Agrarian Reform Programs.  

National Technical Information Service (NTIS)

Compensation problems arise whenever land is redistributed under a land reform program. Among these are: difficulties in determining a reasonable value for the land, effects of inflation on the value of the compensation, effects of the form of compensatio...

J. T. Steele

1964-01-01

270

Evaluation of Seaquest 'Black Diamond' Buoyancy Compensator.  

National Technical Information Service (NTIS)

NEDU was tasked to conduct a survey of commercially available buoyancy compensators (BCs), and perform testing to determine which BC perform satisfactorily. Buoyancy compensator evaluation was conducted in three phases. Phase I, receipt inspection of the ...

C. J. Zanoni

2001-01-01

271

[Compensation of the rectum muscle dysfunction].  

PubMed

The possibility of compensating for the inborn pathology of the obturative apparatus of the rectum has been examined. An adequate experimental model of encopresis and a method of transplantological compensation of this pathological state have been developed. PMID:21268362

Kulikov, D A; Mashkov, A E; Kulikov, A V; Shumski?, V I

272

Algorithm Engineering  

Microsoft Academic Search

Algorithm Engineering is concerned with the design, analysis, implementation, tun- ing, debugging and experimental evaluation of computer programs for solving algorithmic problems. It provides methodologies and tools for developing and engineering efficient al- gorithmic codes and aims at integrating and reinforcing traditional theoretical approaches for the design and analysis of algorithms and data structures.

Camil Demetrescu; Irene FinocchiGiuseppe; F. Italianok

273

38 CFR 21.3024 - Nonduplication; Federal Employees' Compensation Act.  

Code of Federal Regulations, 2013 CFR

...Nonduplication; Federal Employees' Compensation Act. 21.3024 Section...Nonduplication; Federal Employees' Compensation Act. (a) Civilian...Programs, under the Federal Employees' Compensation Act (FECA) based...

2013-07-01

274

45 CFR 302.65 - Withholding of unemployment compensation.  

Code of Federal Regulations, 2012 CFR

...accordance with agreements under any Federal unemployment compensation law). It includes extended benefits, unemployment compensation for Federal employees, unemployment compensation for ex-servicemen, trade readjustment allowances,...

2012-10-01

275

77 FR 4885 - Patent Compensation Board Regulations  

Federal Register 2010, 2011, 2012, 2013

...The EBCA served as the Patent Compensation Board under the...to the EBCA operating as the Patent Compensation Board. DOE is...member panel to serve as the Patent Compensation Board. The Secretary...initial regulatory flexibility analysis for any rule that by law...

2012-02-01

276

Optimal dropout compensation in networked control systems  

Microsoft Academic Search

This paper examines optimal compensation for dropped feedback measurements in a networked control system. A common policy for handling such lost data is to simply use the past data. This case was treated in. This paper extends that prior work to cover a more general class of dropout compensation. The paper's principal result shows that determining the optimal dropout compensator

Qiang Ling; M. D. Lemmon

2003-01-01

277

SSC compensation capability of unbalanced voltage sags  

Microsoft Academic Search

In this paper, the capacity of a static series compensator (SSC) to compensate for voltage sags is discussed, and a complete analysis of the effects of unbalanced sags on the SSC compensation capability is carried out. Expressions are obtained for the missing voltage during unbalanced voltage sags. These expressions are used to estimate how often a voltage sag occurs where

Federica Fornari; Renato Procopio; M. H. J. Bollen

2005-01-01

278

28 CFR 345.54 - Overtime compensation.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Overtime compensation. 345...INDUSTRIES (FPI) INMATE WORK PROGRAMS Inmate Pay and Benefits § 345.54 Overtime compensation. An...other than the scheduled work week (e.g., Saturday...be compensated at the overtime...

2013-07-01

279

A static compensator model for the EMTP  

Microsoft Academic Search

A static voltampere-reactive (VAr) compensator (SVC) model based on nodal analysis, is presented. The model is integrated in the electromagnetic transients program (EMTP) with minimal interface error and by taking into account initialization. The model is basically a generic compensator using thyristor controlled reactors. The models are modular to represent adequately compensators of different designs while being detailed enough for

S. Lefebvre; L. Gerin-Lajoie

1992-01-01

280

Coal workers' pneumoconiosis and compensation in Kentucky  

SciTech Connect

Coal Workers' Pneumoconiosis has been a compensable disease since the 1960s. In 1987 the Kentucky Workers' Compensation Law was changed to provide reduced benefits for coal miners with radiographic evidence of Black Lung Disease, but little or no respiratory impairment. This paper reports a typical case of Black Lung today and discusses the status of workers' compensation for this disease in Kentucky.

Westerfield, B.T.

1993-04-01

281

Management compensation. A reward systems approach.  

PubMed

Across the nation, businesses are rethinking the way performance is rewarded. We are witnessing the emergence of newer, more innovative compensation systems. Today's nurse executive is challenged to design systems for management compensation that reward achievement, performance, and contribution. The author describes a reward systems approach to compensation based on contemporary concepts related to pay. PMID:1870005

Flarey, D L

282

Race and compensation in professional football  

Microsoft Academic Search

Although there have been numerous studies on the effect of race on the compensation of National Basketball Association and Major League Baseball players, there have been only three prior studies that investigated the effect of race on the compensation of National Football League (NFL) players. Two found no evidence of racial discrimination in NFL player compensation, while one found that,

Mark Gius; Donn Johnson

2000-01-01

283

Self Organization in Compensated Semiconductors  

Microsoft Academic Search

In partially compensated semiconductor (PCS) Fermi level is pinned to donor sub-band. Due to positional randomness and almost isoenergetic hoppings, donor-spanned electronic subsystem in PCS forms fluid-like highly mobile collective state. This makes PCS playground for pattern formation, self-organization, complexity emergence, electronic neural networks, and perhaps even for origins of life, bioevolution and consciousness. Through effects of impact and\\/or Auger

Alexander A. Berezin

2004-01-01

284

Compensation techniques in accelerator physics  

NASA Astrophysics Data System (ADS)

Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Two problems involving compensation are studied in the context of the MEIC (Medium Energy Electron Ion Collider) project at Jefferson Laboratory. Several chromaticity (the energy dependence of the particle tune) compensation methods are evaluated numerically and deployed in a figure eight ring designed for the electrons in the collider. Furthermore, transverse coupling optics have been developed to compensate the coupling introduced by the spin rotators in the MEIC electron ring design.

Sayed, Hisham Kamal

285

20 CFR 226.62 - Computing average monthly compensation.  

Code of Federal Regulations, 2013 CFR

...Average Monthly Compensation § 226.62 Computing average monthly compensation. The employee's average monthly compensation is computed by first determining the employee's highest 60 months of railroad compensation (disregarding...

2013-04-01

286

20 CFR 226.62 - Computing average monthly compensation.  

Code of Federal Regulations, 2010 CFR

The employee's average monthly compensation is computed by first determining the employee's highest 60 months of railroad compensation (disregarding compensation in excess of the maximum creditable tier II compensation for that...

2009-04-01

287

List mode reconstruction for PET with motion compensation: A simulation study  

SciTech Connect

Motion artifacts can be a significant factor that limits the image quality in high-resolution PET. Surveillance systems have been developed to track the movements of the subject during a scan. Development of reconstruction algorithms that are able to compensate for the subject motion will increase the potential of PET. In this paper we present a list mode likelihood reconstruction algorithm with the ability of motion compensation. The subject motion is explicitly modeled in the likelihood function. The detections of each detector pair are modeled as a Poisson process with time-varying rate function. The proposed method has several advantages over the existing methods. It uses all detected events and does not introduce any interpolation error. Computer simulations show that the proposed method can compensate simulated subject movements and that the reconstructed images have no visible motion artifacts.

Qi, Jinyi; Huesman, Ronald H.

2002-07-01

288

List mode reconstruction for PET with motion compensation: A simulation study  

SciTech Connect

Motion artifacts can be a significant factor that limits the image quality in high-resolution PET. Surveillance systems have been developed to track the movements of the subject during a scan. Development of reconstruction algorithms that are able to compensate for the subject motion will increase the potential of PET. In this paper we present a list mode likelihood reconstruction algorithm with the ability of motion compensation. The subject moti is explicitly modeled in the likelihood function. The detections of each detector pair are modeled as a Poisson process with time vary ingrate function. The proposed method has several advantages over the existing methods. It uses all detected events and does not introduce any interpolation error. Computer simulations show that the proposed method can compensate simulated subject movements and that the reconstructed images have no visible motion artifacts.

Qi, Jinyi; Huesman, Ronald H.

2002-07-03

289

Novel dispersion compensation method for cross-coupling measurement in PM-PCF based on OCDP  

NASA Astrophysics Data System (ADS)

For polarization maintaining photonic crystal fiber (PM-PCF), the cross-coupling measurement can be severely affected by interferogram broadening, due to the large inter-mode chromatic dispersion. In this paper, a novel dispersion compensation method is proposed to mitigate the influence, including a frequency domain algorithm and investigation of the dispersion coefficient for a phase packet in algorithm. A numerical simulation and measurement of birefringence as a function of wavelength reveal that the dispersion coefficient in PM-PCF is much larger than that in PANDA-PM fiber. After compensation, the accuracy of coupling strength measured can be restored and spatial resolution is improved. Experiments show the compensation provides high accuracy with average relative error less than 0.31% and spatial resolution improved 4.1 times.

Jin, Jing; Wang, Shu; Song, Jingming; Song, Ningfang; Sun, Zuoming; Jiang, Man

2013-10-01

290

Real-time compensation for tool form errors in turning using computer vision  

SciTech Connect

Deviations from the circular shape of the cutting edge of a single-point turning tool cause form errors in the workpiece during contour cutting. One can compensate for these tool-form errors by determining the size of the effective deviation at a particular instant during cutting, and then adjusting the position of the cutting tool accordingly. An algorithm for the compensation of tool-nose-radius errors in real time has been developed and implemented on a CNC fuming center. A previously developed computer-vision-based tool- inspection system is used to determine the size of the deviations. Information from this system is fed to the error compensation computer which modifies the tool path in real time. Workpieces were cut utilizing the compensation system and were inspected on a coordinate measuring machine. Significant improvements in workpiece form were obtained.

Nobel, G.; Donmez, M.A.; Burton, R.

1990-12-31

291

Real-time compensation for tool form errors in turning using computer vision  

SciTech Connect

Deviations from the circular shape of the cutting edge of a single-point turning tool cause form errors in the workpiece during contour cutting. One can compensate for these tool-form errors by determining the size of the effective deviation at a particular instant during cutting, and then adjusting the position of the cutting tool accordingly. An algorithm for the compensation of tool-nose-radius errors in real time has been developed and implemented on a CNC fuming center. A previously developed computer-vision-based tool- inspection system is used to determine the size of the deviations. Information from this system is fed to the error compensation computer which modifies the tool path in real time. Workpieces were cut utilizing the compensation system and were inspected on a coordinate measuring machine. Significant improvements in workpiece form were obtained.

Nobel, G.; Donmez, M.A.; Burton, R.

1990-01-01

292

Phase unwrapping for noisy phase map using localized compensator.  

PubMed

Phase unwrapping for a noisy image suffers from many singular points. Singularity-spreading methods are useful for the noisy image to regularize the singularity. However, the methods have a drawback of distorting phase distribution in a regular area that contains no singular points. When the singular points are confined in some local areas, the regular region is not distorted. This paper proposes a new phase unwrapping algorithm that uses a localized compensator obtained by clustering and by solving Poisson's equation for the localized areas. The numerical results demonstrate that the proposed method can improve the accuracy compared with other singularity-spreading methods. PMID:22858936

Tomioka, Satoshi; Nishiyama, Shusuke

2012-07-20

293

Motion compensated tomography reconstruction of coronary arteries in rotational angiography.  

PubMed

This paper deals with the 3-D reconstruction of the coronary tree from a rotational X-ray projection sequence. It describes the following three stages: the reconstruction of the 3-D coronary tree at different phases of the cardiac cycle, the motion estimation, and the motion-compensated tomographic reconstruction of the 3-D coronary tree at one given phase using all the available projections. Our method is tested on a series of simulated images computed from the projection of a segmented dynamic volume sequence acquired in multislice computed tomography imaging. Performances are comparable to those obtained by reconstruction of a statical coronary tree using an algebraic reconstruction technique algorithm. PMID:19272935

Bousse Ast, Alexandre; Zhou, Jian; Yang, Guanyu; Bellanger, Jean-Jacques; Toumoulin, Christine

2008-10-14

294

Motion compensated fan-beam reconstruction for nonrigid transformation.  

PubMed

We develop an approximate fan-beam algorithm to reconstruct an object with time-dependent nonrigid transformation such as the heart. The method is in the form of derivative backprojection filtering with compensation of affine transformations on a local basis. Computer simulations showed the proposed method significantly reduces image artifact due to nonrigid motion. Therefore, with very little motion artifact, the proposed method allowed us to reconstruct images from projections over about one motion cycle, resulting in reduced image noise level down to 40% of the current level. PMID:18599396

Taguchi, Katsuyuki; Kudo, Hiroyuki

2008-01-01

295

NIOS II processor-based acceleration of motion compensation techniques  

NASA Astrophysics Data System (ADS)

This paper focuses on the hardware acceleration of motion compensation techniques suitable for the MPEG video compression. A plethora of representative motion estimation search algorithms and the new perspectives are introduced. The methods and designs described here are qualified for medical imaging area where are involved larger images. The structure of the processing systems considered has a good fit for reconfigurable acceleration. The system is based in a platform like FPGA working with the Nios II Microprocessor platform applying C2H acceleration. The paper shows the results in terms of performance and resources needed.

González, Diego; Botella, Guillermo; Mookherjee, Soumak; Meyer-Bäse, Uwe; Meyer-Bäse, Anke

2011-05-01

296

A compensated vector control scheme of a synchronous reluctance motor including saturation and iron losses  

Microsoft Academic Search

A compensated vector control algorithm for a synchronous reluctance motor (SRM) including saturation and iron losses is presented. It is shown that the current components that directly govern the torque production have been very well regulated by the proposed control scheme. The computer simulation and experimental results indicate a substantial improvement of torque performance for the vector-controlled SRM

L. Xu; J. Yao

1992-01-01

297

A compensated vector control scheme of a synchronous reluctance motor including saturation and iron losses  

Microsoft Academic Search

A compensated vector control algorithm for a synchronous reluctance motor including saturation and iron losses is presented. It is shown that the current components which directly govern the torque production are well regulated by the proposed control scheme. The comparison made by computer simulation indicates a substantial improvement of torque performance for the vector controlled synchronous reluctance motor

Longya Xu; Jiping Yao

1991-01-01

298

Compensation of Terrain Azimuthal Slope Effects in Geophysical Parameter Studies Using Polarimetric SAR Data  

Microsoft Academic Search

The existence of significant terrain relief reduces the accuracy of algorithms intended to extract geophysical parameters from polarimetric synthetic aperture radar (SAR) images. For this reason most inversion studies attempting to estimate biomass, crop type, snow-cover, surface roughness, or soil moisture, from SAR data are best done in areas of flat earth. In areas which require compensation for topography, limited

Dale L. Schuler; Jong-Sen Lee; Thomas L. Ainsworth

1999-01-01

299

DSP based control of shunt active power filters for global or selective harmonics compensation  

Microsoft Academic Search

This paper presents the study of a shunt active power filter which compensates all or a specified mains current harmonics generated by a typical nonlinear load. The control is mixed and use a digital signal processor (DSP TMS320C40). It allows to test and validate easily different current or DC voltage control algorithms. A fundamental positive detector is realised to enlarge

M. Machmoum; N. Bruyant

2000-01-01

300

Illumination compensation for face recognition by genetic optimization of the Self-Quotient Image method  

Microsoft Academic Search

Face detection and recognition depend strongly on illumination conditions. In this paper, we present improvements in the illumination compensation method called Self Quotient Image (SQI) applied to face recognition. Using genetic algorithms (GA) we select parameters of the SQI method to improve face recognition. The parameters optimized by the GA were: the fraction of the mean value within the region

Claudio A. Perez; Luis E. Castillo

2009-01-01

301

ATP-EMTP Investigation of a New Distance Protection Principle for Series Compensated Lines  

Microsoft Academic Search

A new algorithm for the first zone of protective distance relays for transmission lines compensated by series capacitors, installed in the middle and at both ends, is pre- sented. The concept relies on determining two conditional impedances and comparing them with three characteristics specially shaped on the impedance plan. The conditional im- pedances are calculated from the fault loop quantities

M. M. Saha; E. Rosolowki; J. Izykowski

2003-01-01

302

Adaptive stick-slip friction compensation using dynamic fuzzy logic system  

Microsoft Academic Search

A dynamic fuzzy logic based adaptive algorithm is proposed for reducing the effect of stick slip friction present in 1-DOF (one degree of freedom) mechanical mass system. The control scheme proposed is an online identification and indirect adaptive control, in which the control input is adjusted adaptively to compensate the effect of nonlinearity. Lyapunov stability analysis is used to ensure

Sreekanth Suraneni; I. N. Kar; R. K. P. Bhatt

2003-01-01

303

Advanced processing for motion-compensated reconstruction in cardiac cone-beam CT  

Microsoft Academic Search

Cardiac CT image reconstruction suffers from artifacts due to heart motion during acquisition. In order to mitigate these effects, it is common practice to choose a protocol with minimal gating window and fast gantry rotation. In addition, it is possible to estimate heart motion retrospectively and to incorporate the information in a motion-compensated reconstruction (MCR). If shape tracking algorithms are

Udo van Stevendaal; Peter Forthmann; Thomas Köhler; Jens von Berg; Cristian Lorenz; Michael Grass

2009-01-01

304

Fully 4D motion-compensated reconstruction of cardiac SPECT images  

Microsoft Academic Search

In this paper, we investigate the benefits of a spatiotemporal approach for reconstruction of image sequences. In the proposed approach, we introduce a temporal prior in the form of motion compensation to account for the statistical correlations among the frames in a sequence, and reconstruct all the frames collectively as a single function of space and time. The reconstruction algorithm

Erwan Gravier; Yongyi Yang; Michael A. King; Mingwu Jin

2006-01-01

305

Motion-compensated fully 4D reconstruction of gated cardiac sequences  

Microsoft Academic Search

In this paper we investigate the benefits of a spatio-temporal approach for reconstruction of cardiac image sequences. We introduce a temporal prior based on motion-compensation to enforce temporal correlations along the curved trajectories that follow the cardiac motion. The image frames in a sequence are reconstructed simultaneously through maximum a posteriori (MAP) estimation. We evaluated the performance of our algorithm

Erwan Gravier; Yongyi Yang

2005-01-01

306

Motion-compensated reconstruction of gated cardiac SPECT images using a deformable mesh model  

Microsoft Academic Search

We propose an algorithm for iterative, motion-compensated reconstruction of cardiac-gated SPECT. Dose limitations in SPECT lead to high level of noise in the projection data and further in the reconstructed images. Several reconstruction techniques have been reported to mitigate for the noise effects but they process each time frame individually and do not account for data temporal correlation. Advanced methods

Thibault Marin; Miles N. Wernick; Yongyi Yang; Jovan G. Brankov

2010-01-01

307

Wavefront curvature limitations and compensation to polar format processing for synthetic aperture radar images.  

SciTech Connect

Limitations on focused scene size for the Polar Format Algorithm (PFA) for Synthetic Aperture Radar (SAR) image formation are derived. A post processing filtering technique for compensating the spatially variant blurring in the image is examined. Modifications to this technique to enhance its robustness are proposed.

Doerry, Armin Walter

2006-01-01

308

HALOE Algorithm Improvements for Upper Tropospheric Sounding.  

National Technical Information Service (NTIS)

This report details the ongoing efforts by GATS, Inc., in conjunction with Hampton University and University of Wyoming, in NASA's Mission to Planet Earth Upper Atmosphere Research Satellite (UARS) Science Investigator Program entitled 'HALOE Algorithm Im...

J. M. Russell L. L. Gordley M. E. Hervig M. J. McHugh R. E. Thompson

2001-01-01

309

Atmospheric Effect  

Microsoft Academic Search

AN atmospheric effect, which is sometimes observed in England, displayed itself here in great beauty yesterday. The western sun had been cut off from us by an intervening ridge, while the upper atmosphere was still filled with his light. There was a good deal of opalescent haze in the atmosphere, which, had the sun shone upon it uniformly, would have

John Tyndall

1872-01-01

310

Development of globally applicable algorithm to estimate land surface temperature using satellite-borne microwave radiometer data  

NASA Astrophysics Data System (ADS)

In order to understand the climate system of the Earth, it is essential to globally estimate a land surface temperature (LST) by remote-sensing satellite. Some algorithms to estimate LST using infrared (IR) radiometers have already been developed. However, LST estimated by these algorithms has a large uncertainty under some weather conditions since it is difficult to discriminate an IR radiation from the ground from that from clouds. In contrast, a microwave radiometer is less subject to weather conditions though its resolution is coarse. Therefore, if appropriate data processing is applied to compensate for this coarse resolution, microwave radiometers might become more suitable for estimating LST than IR radiometers. Based on this concept, we first developed a data processing method to extract local and faint changes from data of the satellite-borne microwave radiometer AMSR-E and are aimed to develop the globally applicable algorithm to estimate LST. This algorithm being developed at present calculates microwave radiation from the ground from brightness temperatures of vertically and horizontally polarized signals at 18.7 GHz and 23.8 GHz observed by AMSR-E with atmosphere temperature and water vapor profiles simultaneously observed by AIRS and AMSU. LST is then estimated from these calculated microwave radiation from the ground. We present the development and verification process of this algorithm.

Maeda, T.; Imaoka, K.

2009-04-01

311

Improved Polarimetric Calibration for Atmospheric Radars  

Microsoft Academic Search

Polarization properties of radar waves that are scattered from atmospheric objects are of great interest in meteorological studies. However, polarimetric radar measurements are often not sufficiently accurate for retriev- ing physical properties of targets. To compensate for errors, radar polarimetric calibration is applied. Typical calibrations are performed based on measurements of point targets with known scattering matrices located in the

DMITRI N. MOISSEEV; CHRISTINE M. H. UNAL; LEO P. L IGTHART

2002-01-01

312

Interactive atmosphere  

NSDL National Science Digital Library

Where is ozone located in the atmosphere? This informational activity, part of an interactive laboratory series for grades 8-12, explores the changes in ozone concentration with altitude. Students are introduced to layers of the atmosphere and the amount of ozone found at each layer of the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The activity also discusses why the addition of ozone to the atmosphere at different levels determines the temperatures of those levels. Students can move up and down to different layers of the atmosphere. A temperature scale is shown that runs from the surface of the Earth to the outer most reaches of the atmosphere. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2003-01-01

313

20 CFR 10.417 - What reports are needed when compensation payments continue for children over age 18?  

Code of Federal Regulations, 2013 CFR

...OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL EMPLOYEES' COMPENSATION ACT, AS AMENDED Compensation and Related Benefits Compensation...

2013-04-01

314

20 CFR 10.406 - What are the maximum and minimum rates of compensation in disability cases?  

Code of Federal Regulations, 2013 CFR

...OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL EMPLOYEES' COMPENSATION ACT, AS AMENDED Compensation and Related Benefits Compensation...

2013-04-01

315

Compensation issues tough to navigate  

SciTech Connect

Monthly economic diversity column for the Tri-City Herald - excerpt pasted below: Most industries out there are feeling the shift to a more educated, thus more empowered consumer. The legal field is no exception, which is why it's no surprise that lawsuits are on the rise. Today's society is one in which people are more aware than ever of their rights, and often equally convinced of their entitlements in a number of areas. For business owners, employees represent a major source of potential lawsuits. And compensation is an area of particular concern given that many complaints against employers revolve around it in some way.

Madison, Alison L.

2012-02-12

316

Compensation and Working Conditions Online  

NSDL National Science Digital Library

The US Bureau of Labor Statistics (BLS) has recently begun to provide this publication, a complement to its print counterpart, via the web. The online version mirrors the articles, briefs, and tables of the print version. Some articles are available in text, and some only in Adobe Acrobat [.pdf] format. Each issue is accompanied by relevant BLS tables such as the Employment Cost Index, Major Work Stoppages, and the Occupational Compensation Survey. The present issue (Vol. 3, No. 1) contains articles on professional sports team salary caps, fatal work injuries for 1996, and scientists' earnings.

317

Atmospheric gases  

NSDL National Science Digital Library

Which gases make up the atmosphere? This activity page, part of an interactive laboratory series for grades 8-12, introduces students to the gaseous components of the atmosphere. Students explore the main gases of the atmosphere using a pop-up pie chart. Descriptions of the gases and their percentages in the atmosphere are provided. Students read about water vapor in the atmosphere, and an animation shows a simplified process of precipitation. A pop-up window explains the effects of dust on the atmosphere, and a photograph shows how large amounts of dust in the atmosphere create the reds and oranges displayed in sunsets. Finally, ozone is introduced to students as a necessary component of human life on Earth. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2003-01-01

318

Refractive Index Compensation in Over-Determined Interferometric Systems  

PubMed Central

We present an interferometric technique based on a differential interferometry setup for measurement under atmospheric conditions. The key limiting factor in any interferometric dimensional measurement are fluctuations of the refractive index of air representing a dominating source of uncertainty when evaluated indirectly from the physical parameters of the atmosphere. Our proposal is based on the concept of an over-determined interferometric setup where a reference length is derived from a mechanical frame made from a material with a very low thermal coefficient. The technique allows one to track the variations of the refractive index of air on-line directly in the line of the measuring beam and to compensate for the fluctuations. The optical setup consists of three interferometers sharing the same beam path where two measure differentially the displacement while the third evaluates the changes in the measuring range, acting as a tracking refractometer. The principle is demonstrated in an experimental setup.

Lazar, Josef; Hola, Miroslava; Cip, Ondrej; Cizek, Martin; Hrabina, Jan; Buchta, Zdenek

2012-01-01

319

Frequency-domain delayless active sound quality control algorithm  

Microsoft Academic Search

This paper presents several broadband active sound quality control algorithms based on delayless frequency-domain techniques and subband adaptive filters. This efficient algorithm provides faster convergence and reduced computational complexity as compared to a time-domain active noise equalizer. An equal-loudness compensation method is also introduced for designing the shaping filter to achieve the desired sound quality. Computer simulations validate this algorithm

Sen M. Kuo; Ravi K. Yenduri; Abhijit Gupta

2008-01-01

320

Multi-bunch energy compensation  

SciTech Connect

To obtain a luminosity of 10{sup 34} cm{sup {minus}2} sec{sup {minus}1} in a TeV Linear Collider (TLC), it will probably be necessary to accelerate many bunches in one filling of the rf structure. This has the effect of extracting more energy from the structure and thus enhances the overall efficiency of the accelerator. However, this leads to many problems. First, the train bunches is subject to cummulative beam breakup transversely. This can be controlled by damping the transverse modes with slots in the irises coupled to waveguides. In addition, the energy of the bunches must be kept the same to high precision. For the fundamental mode, this entails adjusting the timing of the rf fill and also the bunch spacing. The higher longitudinal modes, although they do not induce instability, also may lead to bunch-to-bunch variations in energy. However, it also seems possible to damp these modes to cure this problem. Of course, there are also problems associated with damping a train of bunches in a damping ring. In this paper we discuss some of the issues of multi-bunch energy compensation. In the first two sections, we review some basics about energy extraction by a single bunch, and then, multi-bunch energy compensation is treated. We discuss various tolerance issues associated with deviations of amplitude and phase of the rf away from the ideal.

Ruth, R.D.

1988-02-01

321

CEO compensation and hospital financial performance.  

PubMed

Growing interest in pay-for-performance and the level of chief executive officers' (CEOs') pay raises questions about the link between performance and compensation in the health sector. This study compares the compensation of nonprofit hospital CEOs in Ontario, Canada to the three longest reported and most used measures of hospital financial performance. Our sample consisted of 132 CEOs from 92 hospitals between 1999 and 2006. Unbalanced panel data were analyzed using fixed effects regression. Results suggest that CEO compensation was largely unrelated to hospital financial performance. Inflation-adjusted salaries appeared to increase over time independent of hospital performance, and hospital size was positively correlated with CEO compensation. The apparent upward trend in salary despite some declines in financial performance challenges the fundamental assumption underlying this article, that is, financial performance is likely linked to CEO compensation in Ontario. Further research is needed to understand long-term performance related to compensation incentives. PMID:19605619

Reiter, Kristin L; Sandoval, Guillermo A; Brown, Adalsteinn D; Pink, George H

2009-07-15

322

How to avoid deferred-compensation troubles.  

PubMed

Executive compensation packages have long included stock options and deferred compensation plans in order to compete for talent. Last year, Congress passed a law in response to the Enron debacle, in which executives were perceived to be protecting their deferred compensation at the expense of employees, creditors, and investors. The new law is designed to protect companies and their shareholders from being raided by the very executives that guided the company to financial ruin. Physicians who are part owners of medical practices need to know about the changes in the law regarding deferred compensation and how to avoid costly tax penalties. This article discusses how the changes affect medical practices as well as steps physician-owned clinics can take to avoid the risk of penalty, such as freezing deferred compensation and creating a new deferred compensation plan. PMID:16050311

Freeman, Todd I

2005-06-01

323

Vertical vibration analysis for elevator compensating sheave  

NASA Astrophysics Data System (ADS)

Most elevators applied to tall buildings include compensating ropes to satisfy the balanced rope tension between the car and the counter weight. The compensating ropes receive tension by the compensating sheave, which is installed at the bottom space of the elevator shaft. The compensating sheave is only suspended by the compensating ropes, therefore, the sheave can move vertically while the car is traveling. This paper shows the elevator dynamic model to evaluate the vertical motion of the compensating sheave. Especially, behavior in emergency cases, such as brake activation and buffer strike, was investigated to evaluate the maximum upward motion of the sheave. The simulation results were validated by experiments and the most influenced factor for the sheave vertical motion was clarified.

Watanabe, Seiji; Okawa, Takeya; Nakazawa, Daisuke; Fukui, Daiki

2013-07-01

324

Detection algorithms for hyperspectral imaging applications  

Microsoft Academic Search

We introduce key concepts and issues including the effects of atmospheric propagation upon the data, spectral variability, mixed pixels, and the distinction between classification and detection algorithms. Detection algorithms for full pixel targets are developed using the likelihood ratio approach. Subpixel target detection, which is more challenging due to background interference, is pursued using both statistical and subspace models for

D. Manolakis; G. Shaw

2002-01-01

325

Multipurpose Active\\/Passive Motion Compensation System  

Microsoft Academic Search

A microprocessor-controlled active\\/passive motion compensation system has been developed for deploying a variety of geotechnical in-situ testing devices with mobile drilling rigs from low-cost service vessels. The light-weight rotary heave compensator incorporates a hydraulic motor as the compensator actuator and a servo-controlled closed loop pump to reduce the air storage and power requirements. Unique features of the system are the

R. A. Sullivan; M. Davenport; R. Clements

1984-01-01

326

Neutral Atmospheres  

NASA Astrophysics Data System (ADS)

This paper summarizes the understanding of aeronomy of neutral atmospheres in the solar system, discussing most planets as well as Saturn's moon Titan and comets. The thermal structure and energy balance is compared, highlighting the principal reasons for discrepancies amongst the atmospheres, a combination of atmospheric composition, heliocentric distance and other external energy sources not common to all. The composition of atmospheres is discussed in terms of vertical structure, chemistry and evolution. The final section compares dynamics in the upper atmospheres of most planets and highlights the importance of vertical dynamical coupling as well as magnetospheric forcing in auroral regions, where present. It is shown that a first order understanding of neutral atmospheres has emerged over the past decades, thanks to the combined effects of spacecraft and Earth-based observations as well as advances in theoretical modeling capabilities. Key gaps in our understanding are highlighted which ultimately call for a more comprehensive programme of observation and laboratory measurements.

Mueller-Wodarg, I. C. F.; Strobel, D. F.; Moses, J. I.; Waite, J. H.; Crovisier, J.; Yelle, R. V.; Bougher, S. W.; Roble, R. G.

327

Image deblurring and near-real-time atmospheric seeing estimation through the employment of convergence of variance  

NASA Astrophysics Data System (ADS)

A new image reconstruction algorithm is presented that will remove the effect of atmospheric turbulence on motion compensated frame average images. The primary focus of this research was to develop a blind deconvolution technique that could be employed in a tactical military environment where both time and computational power are limited. Additionally, this technique can be employed to measure atmospheric seeing conditions. In a blind deconvolution fashion, the algorithm simultaneously computes a high resolution image and an average model for the atmospheric blur parameterized by Fried's seeing parameter. The difference in this approach is that it does not assume a prior distribution for the seeing parameter, rather it assesses the convergence of the image's variance as the stopping criteria and identification of the proper seeing parameter from a range of candidate values. Experimental results show that the convergence of variance technique allows for estimation of the seeing parameter accurate to within 0.5 cm and often even better depending on the signal to noise ratio.

Neff, Brian J.; MacManus, Quentin D.; Cain, Stephen C.; Martin, Richard K.

2013-01-01

328

The GODFIT Direct Fitting Algorithm: A New Approach for Total Ozone Retrieval From GOME  

NASA Astrophysics Data System (ADS)

We present a new Direct Fitting algorithm (GODFIT) for the retrieval of total ozone amounts from nadir viewing remote sensing spectrometers (such as GOME, SCIAMACHY, OMI and GOME-2) which take earthshine measurements in the UV ozone Huggins bands. The algorithm is designed for direct comparison with measurements, and all radiative transfer (RT) calculations are done from scratch. We use the linearized RT model LIDORT, which has a single-call facility for simultaneous computations of radiances and fast analytic calculations of Jacobians with respect to surface and atmospheric properties. RT calculations require an input profile of ozone partial columns; we use a column-classified ozone profile climatology (the TOMS Version 8 data set) which provides a unique map between the fitted total column and the input RT profile. To compensate for lack of knowledge of tropospheric aerosol, we perform calculations in a Rayleigh atmosphere and fit for the surface albedo as an internal closure parameter; the algorithm is less sensitive to the presence of aerosol than DOAS-AMF algorithms customarily used for this retrieval. The Ring effect is important in the UV, and GODFIT contains a new treatment for the correction of interference effects due to the filling-in of ozone molecular features by inelastic rotational Raman scattering. The algorithm is flexible and direct, and operates without the need for extensive look-up tables. The algorithm was applied to a subset of some 2000 GOME orbits used in validation studies for the total ozone product. The algorithm can process one orbit (~2000 scenes) in under half an hour. Results were compared with ground data from a well-documented network of surface stations, with TOMS total ozone measurements (Version 8), and also with GOME-derived columns from the latest version of the GDP (operational GOME Data Processor DOAS-type total ozone algorithm). With the new results, previously observed seasonality and solar angle dependencies are greatly reduced or even eliminated in most latitudes and time zones (the exception is Antartica in the Austral Spring). New results for GOME total ozone are now of comparable accuracy to ground-based data, and in this regard, the 8-year GOME ozone data record will become suitable for trend analysis and climate studies in the near future. This application for GOME is the first proof of the direct fitting concept, and the method shows great potential for further applications in hyperspectral remote sensing.

Spurr, R. J.; van Roozendael, M.; Lambert, J.; Fayt, C.

2004-05-01

329

Pluto's atmosphere  

NASA Astrophysics Data System (ADS)

Airborne CCD photometer observations of Pluto's June 9, 1988 stellar occultation have yielded an occultation lightcurve, probing two regions on the sunrise limb 2000 km apart, which reveals an upper atmosphere overlying an extinction layer with an abrupt upper boundary. The extinction layer may surround the entire planet. Attention is given to a model atmosphere whose occultation lightcurve closely duplicates observations; fits of the model to the immersion and emersion lightcurves exhibit no significant derived atmosphere-structure differences. Assuming a pure methane atmosphere, surface pressures of the order of 3 microbars are consistent with the occultation data.

Elliot, J. L.; Dunham, E. W.; Bosh, A. S.; Slivan, S. M.; Young, L. A.; Wasserman, L. H.; Millis, R. L.

1989-01-01

330

Sag compensated vibration isolation mount  

NASA Astrophysics Data System (ADS)

A sag-compensated vibration isolation mount includes a cylindrical rubber body element and a circular band extending around the body element. The band is formed from a shape-memory alloy metal which has a predetermined transition temperature. The band is operative for restricting outward bulging and sagging of the body element when the body element is subjected to an axial load at a temperature above the transition temperature. The band has a first length at a temperature above the transition temperature and it is stretchable to a second length at a temperature below the transition temperature. At temperatures below the transition temperature, the body element normally stretches the band to its second length. However, when the band is heated above its transition temperature, the band rapidly decreases in length to its first length to forcibly compress the body element and restrict outward bulging of the body element.

Dickinson, Stuart C.

1994-07-01

331

SAG compensated vibration isolation mount  

NASA Astrophysics Data System (ADS)

A sag-compensated vibration isolation mount includes a cylindrical rubber body element and a circular band extending around the body element. The band is formed from a shape-memory alloy metal which has a predetermined transition temperature. The band is operative for restricting, outward bulging and sagging of the body element when the body element is subjected to an axial load at a temperature above the transition temperature. The band has a first length at a temperature above the transition temperature and it is stretchable to a second length at a temperature below the transition temperature. At temperatures below the transition temperature, the body element normally stretches the band to its second length. However, when the band is heated above its transition temperature, the band rapidly decreases in length to its first length to forcibly compress the body element and restrict outward bulging of the body element.

Dickinson, Stuart

1993-08-01

332

Light shift compensated quantum memories  

NASA Astrophysics Data System (ADS)

Quantum telecommunication could provide secure long-distance data transfer. Direct transmission losses in optical fiber scale exponentially with distance. The quantum repeater protocol allows one to reach polynomial scaling of the communication rate with distance. The quantum repeater relies on long-lived quantum memory elements. Here we report on our recent progress in extending the lifetime of quantum memory based on an ensemble of cold rubidium atoms confined in an optical lattice. Previously observed coherence times (˜ 7 ms) were limited by ac Stark broadening of the ground state hyperfine transition. Two different light shift compensation schemes based on two photon transitions and magnetically-dressed optical potentials are reported. We reach ˜1/3 second lifetimes for stored classical light pulses and similar values for single quanta.

Dudin, Yaroslav O.; Zhao, Ran; Jenkins, Stewart D.; Kennedy, Brian; Kuzmich, Alex

2010-03-01

333

Compensating for cold war cancers.  

PubMed

Although the Cold War has ended, thousands of workers involved in nuclear weapons production are still living with the adverse health effects of working with radioactive materials, beryllium, and silica. After a series of court battles, the U.S. government passed the Energy Employees Occupational Illness Act in October 2000 to financially assist workers whose health has been compromised by these occupational exposures. Now work is underway to set out guidelines for determining which workers will be compensated. The National Institute for Occupational Safety and Health has been assigned the task of developing a model that can scientifically make these determinations, a heavy task considering the controversies that lie in estimating low-level radiation risks and the inadequate worker exposure records kept at many of the plants. PMID:12117658

Parascandola, Mark J

2002-07-01

334

Algorithm Analysis.  

National Technical Information Service (NTIS)

This report lists known problems associated with fix estimation and emitter identification. In many cases a list of known errors associated with the algorithm itself is appended. Finally, MARC described its simulation model is described. Keywords: Fix est...

M. W. Rennie J. Onghre

1983-01-01

335

The atmospheric correction procedure for CMODIS  

Microsoft Academic Search

Ocean color satellites measure radiance at the top of atmosphere, while water-leaving radiance at sea surface is needed to derive ocean color information. It is necessary to develop atmospheric correction algorithms to obtain the water-leaving radiance from satellite-measured radiance. A kind of ocean color hyperspectral sensor called Chinese Moderate Resolution Imaging Spectrometer (CMODIS) on \\

Zhihua Mao; Delu Pan; Haiqing Huang

2006-01-01

336

FAST COMPENSATION OF GLOBAL LINEAR COUPLING IN RHIC USING AC DIPOLES.  

SciTech Connect

Global linear coupling has been extensively studied in accelerators and several methods have been developed to compensate the coupling coefficient C using skew quadrupole families scans. However, scanning techniques can become very time consuming especially during the commissioning of an energy ramp. In this paper they illustrate a new technique to measure and compensate, in a single machine cycle, global linear coupling from turn-by-turn BPM data without the need of a skew quadrupole scan. The algorithm is applied to RHIC BPM data using AC dipoles and compared with traditional methods.

CALAGA, R.; FRANCHI, A. (GSI), TOMAS, R.(CERN)

2006-06-26

337

Compensation of the Effect of a Detector Solenoid on the Beam Size in the ILC  

SciTech Connect

In the International Linear Collider (ILC) [1] the colliding beams must be focused to the nanometer size in order to reach the desired luminosity. The method of Weak Antisolenoid is used for the compensation of the effect of the Detector Solenoid on the beam size [2], [3]. The studies of this method require the computer simulation of the charged particle's kinematics in the arbitrarily distributed solenoidal, dipole, quadrupole and higher multipole fields. We suggest the mathematical algorithm that allows to optimize parameters of antisolenoid for different configurations of Final Focus magnets and to compensate parasitic effects of the Detector Solenoid on the beam.

Seletskiy, S.; /SLAC

2007-07-06

338

Atmospheric chemistry  

SciTech Connect

This book covers the predictive strength of atmospheric models. The book covers all of the major important atmospheric areas, including large scale models for ozone depletion and global warming, regional scale models for urban smog (ozone and visibility impairment) and acid rain, as well as accompanying models of cloud processes and biofeedbacks.

Sloane, C.S. (General Motors Research Labs., Warren, MI (United States)); Tesche, T.W. (Alpine Geophysics (US))

1991-01-01

339

Atmospheric electricity  

Microsoft Academic Search

Owing to the somewhat explosive development of the science of atmospheric electricity during the past decade this article covers a broad field of activity. The article begins with a description and discussion of the work that has been performed to understand the electrical properties of the basic materials involved in generating processes in the atmosphere, namely ice, water, and sand

C D Stow

1969-01-01

340

Atmospheric Optics  

NSDL National Science Digital Library

This collection, created and maintained by Harald Edens, contains photographs of many different atmospheric optical phenomena. Those phenomena include ice crystal halos, light scattering, and atmospheric refraction, among others. The pictures of each phenomenon are accompanied by a brief explanation of what causes it. Prints of the pictures can be purchased from the web site.

Edens, Harald

2008-04-30

341

The Atmosphere.  

ERIC Educational Resources Information Center

|The composition and dynamics of the earth's atmosphere are discussed, considering the atmosphere's role in distributing the energy of solar radiation received by the earth. Models of this activity which help to explain climates of the past and predict those of the future are also considered. (JN)|

Ingersoll, Andrew P.

1983-01-01

342

Slip compensation for a Mars rover  

Microsoft Academic Search

A system that enables continuous slip compensation for a Mars rover has been designed, implemented, and field-tested. This system is composed of several components that allow the rover to accurately and continuously follow a designated path, compensate for slippage, and reach intended goals in high-slip environments. These components include: visual odometry, vehicle kinematics, a Kalman filter pose estimator, and a

Daniel M. Helmick; Yang Cheng; Daniel S. Clouse; Max Bajracharya; Larry H. Matthies; Stergios I. Roumeliotis

2005-01-01

343

Compensated CIC-cosine decimation filter  

Microsoft Academic Search

This paper presents efficient modification of the CIC-cosine decimation filter. The second order compensator filter is introduced at last decimation stage in order to improve the pass band of interest. The coefficients of the compensator filter are presented as canonical signed digits (CSD) and can be implemented using only adders and shifts. Consequently, the resulting filter is a multiplier free

F. J. T. Torres; G. J. Dolecek

2007-01-01

344

AUTOTUNING OF FRACTIONAL LEAD-LAG COMPENSATORS  

Microsoft Academic Search

In this paper, a method for auto-tuning of a fractional order lead- lag compensator using relay feedback tests is proposed. A design method for this kind of compensators is discussed, based on the magnitude and phase measurement of the plant to be controlled from relay feedback tests at a frequency of interest. Simple relationships among the parameters of this fractional

C. A. Monje; B. M. Vinagre; A. J. Calderón; V. Feliu; Y. Q. Chen

2005-01-01

345

Fatigue compensation during FES using surface EMG  

Microsoft Academic Search

Muscle fatigue limits the effectiveness of FES when applied to regain functional movements in spinal cord injured (SCI) individuals. The stimulation intensity must be manually increased to provide more force output to compensate for the decreasing muscle force due to fatigue. An artificial neural network (ANN) system was designed to compensate for muscle fatigue during functional electrical stimulation (FES) by

Jeffrey Winslow; Patrick L Jacobs; Dejan Tepavac; J. B. Wagenaar

2003-01-01

346

Executive Compensation as an Agency Problem  

Microsoft Academic Search

This paper provides an overview of the main theoretical elements and empirical underpinnings of a managerial power' approach to executive compensation. Under this approach, the design of executive compensation is viewed not only as an instrument for addressing the agency problem between managers and shareholders but also as part of the agency problem itself. Boards of publicly traded companies with

Lucian Arye Bebchuk; Jesse M. Fried

2003-01-01

347

Reconstruction of image sequences using motion compensation  

Microsoft Academic Search

In this paper we study a motion-compensated approach for simultaneous reconstruction of image frames in a time sequence. We treat the frames in a sequence collectively as a single function of both space and time, and define a temporal prior to account for the temporal correlations in a sequence. This temporal prior is defined in a form of motion-compensation, aimed

Yongyi Yang; Erwan J. Gravier

2004-01-01

348

A model of compensation of topographic masses  

NASA Astrophysics Data System (ADS)

The compilation of new global Mohorovi?i? (‘Moho’) topographic data enables the density contrast between the crust and mantle to be estimated. Assuming that this contrast is constant, the minimization of the external gravitational potential induced by the Earth's topographic masses and the Moho discontinuity yields the value of 0.28 g/cm3 for the density jump at the Moho. Moreover, it is shown that the Airy Heiskanen model of compensation only partly compensates the surface topographic masses. To fit the external gravitational potential, induced by the surface topography, the Pratt-Hayford concept of compensation has to be considered. Employing the dynamical flattening of the Earth, the minimum depth of compensation has been estimated at 100 150 km. This means that the topographic masses are compensated throughout the Earth's lithosphere at least.

Martinec, Zden?k

1993-09-01

349

The National Vaccine Injury Compensation Program.  

PubMed

The National Childhood Vaccine Injury Act of 1986 established the National Vaccine Injury Compensation Program to compensate people thought to be injured by certain vaccines. The act's goals are to ensure an adequate supply of vaccines, to stabilize vaccine costs, and to establish and maintain an accessible and efficient setting for providing compensation to people found to have been injured by certain childhood vaccines. In addition, the legislation called for the reporting of adverse events after vaccination, the creation of vaccine-information materials that detail vaccine benefits and risks, and Institute of Medicine studies of possible vaccine-related injuries and encouraged research and development of new and safer vaccines. Over its 22-year history, the National Vaccine Injury Compensation Program has been a key component in stabilizing the US vaccine market through liability protection to both vaccine companies and health care providers and by providing a forum for people, no matter what age, to seek compensation. PMID:21502255

Cook, Katherine M; Evans, Geoffrey

2011-04-18

350

Dosage Compensation of the Sex Chromosomes  

PubMed Central

Differentiated sex chromosomes evolved because of suppressed recombination once sex became genetically controlled. In XX/XY and ZZ/ZW systems, the heterogametic sex became partially aneuploid after degeneration of the Y or W. Often, aneuploidy causes abnormal levels of gene expression throughout the entire genome. Dosage compensation mechanisms evolved to restore balanced expression of the genome. These mechanisms include upregulation of the heterogametic chromosome as well as repression in the homogametic sex. Remarkably, strategies for dosage compensation differ between species. In organisms where more is known about molecular mechanisms of dosage compensation, specific protein complexes containing noncoding RNAs are targeted to the X chromosome. In addition, the dosage-regulated chromosome often occupies a specific nuclear compartment. Some genes escape dosage compensation, potentially resulting in sex-specific differences in gene expression. This review focuses on dosage compensation in mammals, with comparisons to fruit flies, nematodes, and birds.

Disteche, Christine M.

2013-01-01

351

No-fault compensation in New Zealand: harmonizing injury compensation, provider accountability, and patient safety.  

PubMed

In 1974 New Zealand jettisoned a tort-based system for compensating medical injuries in favor of a government-funded compensation system. Although the system retained some residual fault elements, it essentially barred medical malpractice litigation. Reforms in 2005 expanded eligibility for compensation to all "treatment injuries," creating a true no-fault compensation system. Compared with a medical malpractice system, the New Zealand system offers more-timely compensation to a greater number of injured patients and more-effective processes for complaint resolution and provider accountability. The unfinished business lies in realizing its full potential for improving patient safety. PMID:16403765

Bismark, Marie; Paterson, Ron

352

Continuous Glucose Monitoring: Real-Time Algorithms for Calibration, Filtering, and Alarms  

Microsoft Academic Search

Algorithms for real-time use in continuous glucose monitors are reviewed, including calibration, filtering of noisy signals, glucose predictions for hypoglycemic and hyperglycemic alarms, compensation for capillary blood glucose to sensor time lags, and fault detection for sensor degradation and dropouts. A tutorial on Kalman filtering for real-time estimation, prediction, and lag compensation is presented and demonstrated via simulation examples. A

B. Wayne Bequette

2010-01-01

353

An automatic stain removal algorithm of series aerial photograph based on flat-field correction  

Microsoft Academic Search

The dust on the camera's lens will leave dark stains on the image. Calibrating and compensating the intensity of the stained pixels play an important role in the airborne image processing. This article introduces an automatic compensation algorithm for the dark stains. It's based on the theory of flat-field correction. We produced a whiteboard reference image by aggregating hundreds of

Gang Wang; Dongmei Yan; Yang Yang

2010-01-01

354

Influence and Compensation of Truncation Artifacts in MR-Based Attenuation Correction in PET/MR.  

PubMed

The goal of this article is to quantify the influence of truncation artifacts in the magnetic resonance (MR)-based attenuation map (MRMap) on reconstructed positron emission tomography (PET) image volumes and to propose a new method for minimizing this influence. Methods: PET data sets of 20 patients investigated in a Philips Ingenuity PET/MR were reconstructed with and without applying two different methods for truncation compensation (TC1 vendor-provided, TC2 newly developed). In this patient group, the extent of truncation artifacts and quality of the truncation compensation (TC) was assessed visually in the MRMaps. In three additional patients MRMaps generated by algorithm TC2 could be compared to the ground truth of transmission-based attenuation maps obtained with a Siemens ECAT HR(+) scanner. The influence of truncation on regional SUVs in lesions, other hot structures (bladder, kidney, myocardium) and the arms was assessed in suitable volume of interests (VOI). Results: Truncation compensated MRMaps exhibited residual artifacts in the arms in 16 patients for algorithm TC1 and to a lesser extent in eight patients for algorithm TC2. Compared to the transmission-based attenuation maps algorithm TC2 slightly overestimated the size of the truncated arms by 0.3 cm in the radial direction. Without truncation compensation, VOIs located in the trunk showed an average SUVmax underestimation of less than 5.4% relative to the results obtained with TC2. Inside the patients' arms underestimations up to 46.5% were found. Conclusion: In the trunk, standardized uptake values (SUV) underestimations due to truncation artifacts in the MRMap are rather small. Inside the arms, severe SUV underestimations can occur. Therefore, reliable TC is mandatory and can be achieved by applying the newly developed algorithm TC2 which has yielded promising results so far. Implementation of the proposed method is straightforward and should be easily adaptable to other PET/MR systems. PMID:24186268

Schramm, G; Langner, J; Hofheinz, F; Petr, J; Lougovski, A; Beuthien-Baumann, B; Platzek, I; van den Hoff, J

2013-11-01

355

NPP Atmospheric Data Products  

NASA Astrophysics Data System (ADS)

The four instruments, VIsible-InfraRed Radiometer Suite(VIIRS), Cross-track Infrared Sounder(CrIS), Advanced Technology Microwave Sounder ATMS and Ozone Mapping and Profiler Suite (OMPS), on the NPOESS Preparatory Mission(NPP) will provide 27 data products to two primary user communities; operational users in the weather and environmental conditions forecasting communities requiring guaranteed access to real-time data and scientific users primarily interested in studying longer-term climate processes. This presentation will focus on the atmospheric data products that provide data continuity between past, present and future satellite instruments. The data product requirements, algorithm development and product validation processes will be presented.

Gleason, J. F.

2005-12-01

356

Atmospheric absorption in the atmosphere up to 160 km  

NASA Astrophysics Data System (ADS)

This paper describes new algorithms, not previously available, for predicting atmospheric absorption of sound at high altitudes. A basis for estimating atmospheric absorption up to 160 km is described. The estimated values at altitudes above 90 km must be considered as only approximate due to uncertainties about the composition of the atmosphere above 90 km and simplifying assumptions. At high altitudes, classical and rotational relaxation absorption are dominant, as opposed to absorption by molecular vibrational relaxation that is the principle atmospheric absorption loss mechanism for primary sonic booms propagating downward from a cruising supersonic aircraft. Classical and rotational relaxation absorption varies inversely with atmospheric pressure, thus increasing in magnitude at high altitudes as atmospheric pressure falls. However, classical and rotational losses also relax at the high values of frequency/pressure reached at high altitudes and thus, for audio and infrasonic frequencies, begin to decrease at altitudes in the range of 80-160 km. This paper includes: (1) modifications to the existing algorithms in the ISO/ANSI standards for atmospheric absorption at high altitudes, and (2) algorithms for definition of mean atmospheric conditions, including humidity content at high altitude conditions. Also included are suitable values for the temperature-dependent physical parameters of the atmosphere, viscosity, and the specific heat ratio, involved in defining atmospheric absorption at temperatures found at high altitudes. It has been found that carbon dioxide plays a major role in the relaxation of O2 and N2 at high altitudes due to the absence of H2O. Molecular relaxation by CO2, not covered by the current ANSI or ISO standards, is the dominant source of molecular relaxation absorption at altitudes above 60 km at frequencies of 1 Hz and above 10 km at a frequency of 10 kHz. However, at such high altitudes, classical plus rotational losses dominate reaching maximum values at 80-160 km, depending on frequency. In this regime, vibrational relaxation is less important. More accurate predictions of absorption at altitudes above 90 km would require more sophisticated models for the variation in atmospheric viscosity and specific heat ratio above such altitudes.

Sutherland, Louis C.; Bass, Henry E.

2004-03-01

357

Atmospheric Optics  

NSDL National Science Digital Library

Les Cowley, a physicist and expert in atmospheric optics, developed this website to share his knowledge about the visual spectacles produced by light connecting with water drops, dust, and ice crystals. Students can discover how and where the amazing displays are formed. The site is divided into five main categories: Rays and Shadows, Water Droplets, Rainbows, Ice Halos, and High Atmosphere. Within each topic, users can find an abundance of information and amazing images of the particular spectacle. By downloading the HaloSim3 Software in the Ice Halo link, users can view simulations of common and rare halos. Visitors will learn a lot about the atmosphere through this remarkable website.

Cowley, Les

358

Self Organization in Compensated Semiconductors  

NASA Astrophysics Data System (ADS)

In partially compensated semiconductor (PCS) Fermi level is pinned to donor sub-band. Due to positional randomness and almost isoenergetic hoppings, donor-spanned electronic subsystem in PCS forms fluid-like highly mobile collective state. This makes PCS playground for pattern formation, self-organization, complexity emergence, electronic neural networks, and perhaps even for origins of life, bioevolution and consciousness. Through effects of impact and/or Auger ionization of donor sites, whole PCS may collapse (spinodal decomposition) into microblocks potentially capable of replication and protobiological activity (DNA analogue). Electronic screening effects may act in RNA fashion by introducing additional length scale(s) to system. Spontaneous quantum computing on charged/neutral sites becomes potential generator of informationally loaded microstructures akin to "Carl Sagan Effect" (hidden messages in Pi in his "Contact") or informational self-organization of "Library of Babel" of J.L. Borges. Even general relativity effects at Planck scale (R.Penrose) may affect the dynamics through (e.g.) isotopic variations of atomic mass and local density (A.A.Berezin, 1992). Thus, PCS can serve as toy model (experimental and computational) at interface of physics and life sciences.

Berezin, Alexander A.

2004-03-01

359

20 CFR 211.15 - Verification of compensation claimed.  

Code of Federal Regulations, 2013 CFR

...Accounts shall inform the employee that the compensation claimed is not creditable...adjustment crediting the employee with the compensation claimed. If the employer...adjustment crediting the employee with the compensation claimed. [49...

2013-04-01

360

20 CFR 211.5 - Employee representative compensation.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2012-04-01 true Employee representative compensation. 211.5 Section 211.5...RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.5 Employee representative compensation. All payments made by a...

2013-04-01

361

38 CFR 3.708 - Federal Employees' Compensation.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Federal Employees' Compensation. 3.708 Section 3...Elections § 3.708 Federal Employees' Compensation. (a) Military service...Programs, under the Federal Employees' Compensation Act (FECA) based...

2013-07-01

362

20 CFR 211.16 - Finality of records of compensation.  

Code of Federal Regulations, 2013 CFR

...of records of compensation. 211.16...Section 211.16 Employees' Benefits...record of the compensation reported as paid to an employee for a given...then as to the employee's having received no compensation for such...

2013-04-01

363

38 CFR 3.958 - Federal employees' compensation cases.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Federal employees' compensation cases. 3.958 Section...Protection § 3.958 Federal employees' compensation cases. Any award...benefits under the Federal Employees' Compensation Act based on a...

2013-07-01

364

26 CFR 1.85-1 - Unemployment compensation.  

Code of Federal Regulations, 2010 CFR

...the term âunemployment compensation...under a law of the United States, or of a State...in the nature of unemployment compensation...85 of title 5, United States Code, relating to unemployment compensation...

2009-04-01

365

26 CFR 1.85-1 - Unemployment compensation.  

Code of Federal Regulations, 2010 CFR

...the term âunemployment compensation...under a law of the United States, or of a State...in the nature of unemployment compensation...85 of title 5, United States Code, relating to unemployment compensation...

2010-04-01

366

45 CFR 302.65 - Withholding of unemployment compensation.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Withholding of unemployment compensation. 302.65 Section...REQUIREMENTS § 302.65 Withholding of unemployment compensation. The State plan shall...with the administration of the State unemployment compensation laws in accordance...

2011-10-01

367

Employer Costs for Employee Compensation, 1986-98.  

National Technical Information Service (NTIS)

This bulletin provides data on Employer Costs for Employee Compensation (ECEC), a major Bureau of Labor Statistics (BLS) compensation measure. It uses March 1998 ECEC data to examine the structure of compensation cost levels. All ECEC historical data from...

1998-01-01

368

Employer Costs for Employee Compensation, 1986-99.  

National Technical Information Service (NTIS)

This bulletin provides data on Employer Costs for Employee Compensation (ECEC), a major Bureau of Labor Statistics (BLS) compensation measure. It uses March 1999 ECEC data to examine the structure of compensation cost levels. All ECEC historical data from...

2000-01-01

369

40 CFR 1066.260 - Parasitic friction compensation evaluation.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Parasitic friction compensation evaluation. 1066.260...Specifications § 1066.260 Parasitic friction compensation evaluation. (a) Overview...verify the accuracy of the dynamometer's friction compensation. (b) Scope and...

2013-07-01

370

The Shortwave (SW) Clear-Sky Detection and Fitting Algorithm: Algorithm Operational Details and Explanations  

Microsoft Academic Search

This document describes some specifics of the algorithm for detecting clear skies and fitting clear-sky shortwave (SW) functions described in Long and Ackerman (2000). This algorithm forms the basis of the ARM SW FLUX ANAL 1Long VAP. In the Atmospheric Radiation Measurement (ARM) case, the value added procedures (VAP) can be described as having three parts: a front end, a

C. N. Long; K. L. Gaustad

2004-01-01

371

Discrete Packet Analysis for Improved Atmospheric Rejection on Modulated Laser Signals  

SciTech Connect

This slide-show discusses how the method of discrete packet analysis improves atmospheric compensation for quasi-CW fluorescence detection methods. This is key to improving remote sensing capabilities.

O'Neill, M., McKenna, I., DiBenedetto, J., Capelle, G., Trainham, R.

2012-07-19

372

Error Compensation for Area Digital Sun Sensor  

PubMed Central

Compared to the error factors of the Linear Array Digital Sun Sensor (DSS), those of the Area Array DSS are complicated and methods used for error compensation are not valid or simple enough. This paper presents the main error factors of the Area Array DSS and proposes an effective method to compensate them. The procedure of error compensation of Area Array DSS includes three steps. First, the geometric error of calibration is compensated; second, the coordinate map method is used to compensate the error caused by optical refraction; third, the high order polynomial-fitting method is applied to calculate the tangent of the sun angles; finally, the arc tangent method is used to calculate the sun angles. Experimental results of the product of the High Accuracy Sun Sensor indicate that the precision is better than 0.02° during the cone field of view (CFOV) of 10°, and the precision is better than 0.14° during the CFOV 10° to 64°. The proposed compensation method effectively compensates the major error factors and significantly improves the measure precision of the Area APS DSS.

Li, Wen-Yang; Zhang, Gao-Fei; You, Zheng; Xing, Fei

2012-01-01

373

Adaptive compensation of aberrations in ultrafast 3D microscopy using a deformable mirror  

NASA Astrophysics Data System (ADS)

3D imaging using a multiphoton scanning confocal microscope is ultimately limited by aberrations of the system. We describe a system to adaptively compensate the aberrations with a deformable mirror. We have increased the transverse scanning range of the microscope by three with compensation of off-axis aberrations.We have also significantly increased the longitudinal scanning depth with compensation of spherical aberrations from the penetration into the sample. Our correction is based on a genetic algorithm that uses second harmonic or two-photon fluorescence signal excited by femtosecond pulses from the sample as the enhancement parameter. This allows us to globally optimize the wavefront without a wavefront measurement. To improve the speed of the optimization we use Zernike polynomials as the basis for correction. Corrections can be stored in a database for look-up with future samples.

Sherman, Leah R.; Albert, O.; Schmidt, Christoph F.; Vdovin, Gleb V.; Mourou, Gerard A.; Norris, Theodore B.

2000-05-01

374

Real-time inverse hysteresis compensation of piezoelectric actuators with a modified Prandtl-Ishlinskii model.  

PubMed

This paper presents a novel real-time inverse hysteresis compensation method for piezoelectric actuators exhibiting asymmetric hysteresis effect. The proposed method directly utilizes a modified Prandtl-Ishlinskii hysteresis model to characterize the inverse hysteresis effect of piezoelectric actuators. The hysteresis model is then cascaded in the feedforward path for hysteresis cancellation. It avoids the complex and difficult mathematical procedure for constructing an inversion of the hysteresis model. For the purpose of validation, an experimental platform is established. To identify the model parameters, an adaptive particle swarm optimization algorithm is adopted. Based on the identified model parameters, a real-time feedforward controller is implemented for fast hysteresis compensation. Finally, tests are conducted with various kinds of trajectories. The experimental results show that the tracking errors caused by the hysteresis effect are reduced by about 90%, which clearly demonstrates the effectiveness of the proposed inverse compensation method with the modified Prandtl-Ishlinskii model. PMID:22755661

Gu, Guo-Ying; Yang, Mei-Ju; Zhu, Li-Min

2012-06-01

375

The research of wavefront compensation of a reflective beam shaping system  

NASA Astrophysics Data System (ADS)

In order to compensate the low order aberrations effectively and rapidly, a new method is developed to study the wavefront compensation of a reflective beam shaping system by using simulation experiments. The system consists of three cylinder mirrors and a spherical mirror. By inserting different Zernike phase screens, many sizes and species of low order aberrations can be simulated. Then the data communication is set up between Matlab and Zemax based on dynamic data exchange (DDE) technique. The configuration parameters of the system constructed by Zemax could be regarded as variables, and the beam shaping system as the transfer function, overall appropriate optimization algorithm was utilized to solve the optimal configuration to make the compensation system most effective.

Gu, Dianyu; Liu, Wenguang; Zhou, Qiong

2013-09-01

376

Atmospheric Potential  

Microsoft Academic Search

UNDER the above heading Mr. Evan McLennan refers in NATURE, February 13, p. 647, to supposed puzzles in atmospheric electricity. That certain difficulties exist no one can deny, but Mr. McLennan's difficulties might, I think, be removed by consultation of existing text-books. The vertical current which he thinks should exist in the atmosphere does exist, and methods of measuring it

C. CHREE C

1913-01-01

377

Atmospheric pollution  

SciTech Connect

Atmospheric pollution (AP), its causes, and measures to prevent or reduce it are examined in reviews and reports presented at a workshop held in Damascus, Syria in August 1985. Topics discussed include AP and planning studies, emission sources, pollutant formation and transformation, AP effects on man and vegetation, AP control, atmospheric dispersion mechanisms and modeling, sampling and analysis techniques, air-quality monitoring, and applications. Diagrams, graphs, and tables of numerical data are provided.

Pickett, E.E.

1987-01-01

378

Generalized Fried parameter after adaptive optics partial wave-front compensation  

PubMed

Atmospheric turbulence imposes the resolution limit attainable by large ground-based telescopes. This limit is lambda/r(0), where r(0) is the Fried parameter or seeing cell size. Working in the visible, adaptive optics systems can partially compensate for turbulence-induced distortions. By analogy with the Fried parameter, r(0), we have introduced a generalized Fried parameter, rho(0), that plays the same role as r(0) but in partial compensation. Using this parameter and the residual phase variance, we have described the phase structure function, estimated the point-spread function halo size, and derived an expression for the Strehl ratio as a function of the degree of compensation. Finally, it is shown that rho(0) represents the diameter of the coherent cells in the pupil domain. PMID:10795639

Cagigal; Canales

2000-05-01

379

Analysis on dispersion compensation with DCF based on Optisystem  

Microsoft Academic Search

Fiber-optic dispersion and its effect on optical transmission system are analyzed. The most commonly used dispersion compensation fiber (DCF) technology is studied in this article. Three schemes (pre-compensation, post-compensation, mix-compensation of dispersion compensation) of dispersion compensation with DCF are proposed. The simulation model of the WDM based on the Optisystem is presented according to the above principle. The simulation results

Bo-ning Hu; Wang Jing; Wang Wei; Rui-mei Zhao

2010-01-01

380

Rainfall and Radiative Heating Rates from TOGA COARE Atmospheric Budgets  

Microsoft Academic Search

Atmospheric heat and moisture budgets are used to determine rainfall and radiative heating rates over the western Pacific warm pool during the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). Results are compared to independent estimates of these quantities from the other sources. Using the COARE bulk flux algorithm to estimate surface evaporation over the intensive flux array

Richard H. Johnson; Paul E. Ciesielski

2000-01-01

381

Atmospheric Dust  

NSDL National Science Digital Library

Millions of tons of dust are lifted from deserts annually, suspended in the atmosphere, and released to fall on the oceans, but scientists are a long way from understanding the impact of atmospheric dust on the climate and weather systems of Earth or on marine organisms. This radio broadcast explains how the nitrogen, phosphorus and iron released from dust boosts the growth of phytoplankton, which also soak up carbon dioxide and release more gases into the atmosphere. Better monitoring and more sophisticated sensors are giving us a more accurate picture of the dust in the atmosphere; the broadcast reports on investigations of dust from ice cores and on computer simulations of the connections between dust and climate. But the unpredictable nature of dust events makes it extremely difficult to determine their impact on the natural systems of Earth. There are discussions with geographers, oceanographers, environmentalists and climate modelers about atmospheric dust, one of the least understood and most contradictory components of the atmosphere. The broadcast is 28 minutes in length.

382

Sewing algorithm  

SciTech Connect

We present a procedure that in many cases enables the Monte Carlo sampling of states of a large system from the sampling of states of a smaller system. We illustrate this procedure, which we call the sewing algorithm, for sampling states from the transfer matrix of the two-dimensional Ising model.

Booth, Thomas E [Los Alamos National Laboratory; Gubernatis, James E [Los Alamos National Laboratory

2008-01-01

383

An algorithm for the calibration of sensor arrays with sensor gain and phase uncertainties  

Microsoft Academic Search

A powerful, efficient non-iterative array calibration algorithm is presented. The algorithm determines the gain and phase compensation for translational invariant, particularly linear uniform arrays which are the basis for many efficient array processing algorithms. Starting with N measurements of the desired M-element array scan range, the algorithm computes just 2M weighted scalar products of N-element vectors and solves a (M-2)*(M-2)

Markus Ali; Jurgen Gotze; Ruiner Pauli

1993-01-01

384

Prostate implant reconstruction from C-arm images with motion-compensated tomosynthesis  

PubMed Central

Purpose: Accurate localization of prostate implants from several C-arm images is necessary for ultrasound-fluoroscopy fusion and intraoperative dosimetry. The authors propose a computational motion compensation method for tomosynthesis-based reconstruction that enables 3D localization of prostate implants from C-arm images despite C-arm oscillation and sagging. Methods: Five C-arm images are captured by rotating the C-arm around its primary axis, while measuring its rotation angle using a protractor or the C-arm joint encoder. The C-arm images are processed to obtain binary seed-only images from which a volume of interest is reconstructed. The motion compensation algorithm, iteratively, compensates for 2D translational motion of the C-arm by maximizing the number of voxels that project on a seed projection in all of the images. This obviates the need for C-arm full pose tracking traditionally implemented using radio-opaque fiducials or external trackers. The proposed reconstruction method is tested in simulations, in a phantom study and on ten patient data sets. Results: In a phantom implanted with 136 dummy seeds, the seed detection rate was 100% with a localization error of 0.86?±?0.44 mm (Mean?±?STD) compared to CT. For patient data sets, a detection rate of 99.5% was achieved in approximately 1 min per patient. The reconstruction results for patient data sets were compared against an available matching-based reconstruction method and showed relative localization difference of 0.5?±?0.4 mm. Conclusions: The motion compensation method can successfully compensate for large C-arm motion without using radio-opaque fiducial or external trackers. Considering the efficacy of the algorithm, its successful reconstruction rate and low computational burden, the algorithm is feasible for clinical use.

Dehghan, Ehsan; Moradi, Mehdi; Wen, Xu; French, Danny; Lobo, Julio; Morris, W. James; Salcudean, Septimiu E.; Fichtinger, Gabor

2011-01-01

385

Prostate implant reconstruction from C-arm images with motion-compensated tomosynthesis  

SciTech Connect

Purpose: Accurate localization of prostate implants from several C-arm images is necessary for ultrasound-fluoroscopy fusion and intraoperative dosimetry. The authors propose a computational motion compensation method for tomosynthesis-based reconstruction that enables 3D localization of prostate implants from C-arm images despite C-arm oscillation and sagging. Methods: Five C-arm images are captured by rotating the C-arm around its primary axis, while measuring its rotation angle using a protractor or the C-arm joint encoder. The C-arm images are processed to obtain binary seed-only images from which a volume of interest is reconstructed. The motion compensation algorithm, iteratively, compensates for 2D translational motion of the C-arm by maximizing the number of voxels that project on a seed projection in all of the images. This obviates the need for C-arm full pose tracking traditionally implemented using radio-opaque fiducials or external trackers. The proposed reconstruction method is tested in simulations, in a phantom study and on ten patient data sets. Results: In a phantom implanted with 136 dummy seeds, the seed detection rate was 100% with a localization error of 0.86 {+-} 0.44 mm (Mean {+-} STD) compared to CT. For patient data sets, a detection rate of 99.5% was achieved in approximately 1 min per patient. The reconstruction results for patient data sets were compared against an available matching-based reconstruction method and showed relative localization difference of 0.5 {+-} 0.4 mm. Conclusions: The motion compensation method can successfully compensate for large C-arm motion without using radio-opaque fiducial or external trackers. Considering the efficacy of the algorithm, its successful reconstruction rate and low computational burden, the algorithm is feasible for clinical use.

Dehghan, Ehsan; Moradi, Mehdi; Wen, Xu; French, Danny; Lobo, Julio; Morris, W. James; Salcudean, Septimiu E.; Fichtinger, Gabor [School of Computing, Queen's University, Kingston, Ontario K7L-3N6 (Canada); Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, British Columbia V6T-1Z4 (Canada); Vancouver Cancer Centre, Vancouver, British Columbia V5Z-1E6 (Canada); Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, British Columbia V6T-1Z4 (Canada); School of Computing, Queen's University, Kingston, Ontario K7L-3N6 (Canada)

2011-10-15

386

Iterative atmospheric parameters estimation of the tropical atmosphere  

NASA Astrophysics Data System (ADS)

This work describes an iterative algorithm capable of determining the atmospheric parameters (temperature and water vapour profiles) by using NOAA ATOVS data and "in situ" observations currently collected at the Broglio Space Centre (BSC, located in Malindi-Kenya, 40 E, 3 S) of the Centro di Ricerca Progetto San Marco (CRPSM) of the University of Rome "La Sapienza" (Italy). The method is based on the usual approach to the problem of retrieving atmospheric characteristics: 1. a forward model (using the Modtran atmospheric code); 2. a numerical method for solving systems of non-linear equations (by means of a Broyden"s Quasi-Newton methods and a regularization method coupled with a preconditioning to computing stabilized solutions to the ill-posed problems). The retrieval method for the temperature and water vapour is discussed in detail; comparisons are also made with available co-located atmospheric information from balloon-based soundings. The aim of this paper is to evaluate the accuracy of the estimate of the tropical atmosphere parameters using a retrieval algorithm developed by authors, based on Broyden"s method for systems of non-linear equations.

Longo, Francesco; Laneve, Giovanni

2004-02-01

387

Atmospheric chemistry: Natural atmospheric acidity  

NASA Astrophysics Data System (ADS)

Formic acid exerts a significant influence on atmospheric chemistry and rainwater acidity. Satellite observations and model simulations suggest that terrestrial vegetation accounts for around 90% of the formic acid produced annually.

Millet, Dylan B.

2012-01-01

388

Comparative study on computed tomography algorithms  

NASA Astrophysics Data System (ADS)

This study uses Computed Tomography (CT) for reconstructing images of solid propellant rocket motors during static firing tests. Implementation, verification and comparison of four CT algorithms are presented. These four algorithms are: Algebraic Reconstruction Technique, Linear Superposition with Compensation, and Fourier Convolution technique with parallel beams and fan-beam. The phantom used in the comparison between algorithms is similar in cross-section to a solid propellant rocket motor. Comparison between algorithms on the ability to detect artifacts is made. Also, a comparison is made using data obtained by optical tomography of the absorption coefficient inside a 20 mm gas gun barrel. Finally, a comparison of the running time versus number of projections, number of ray sums, and resolution is studied.

Zayed, Nasser; Lawton, Bryan

1994-09-01

389

Collision resolution algorithms for spread spectrum environments  

NASA Astrophysics Data System (ADS)

In some spread spectrum environments, the low energy of the transmitted signals, in conjuction with the existence of channel noise, doesn't allow the distinction between collision and lack of transmissions. For such environments, and for the Poisson user model, the authors propose and analyze stable full feedback sensing and limited feedback sensing synchronous transmission algorithms. They assume binary SNS (success versus nonsuccess) feedback per slot, and the possibility of transmission of phony data by a central node. The highest throughput attained by both the full feedback sensing and the limited feedback sensing algorithms is 0.322, while the latter induces somewhat higher delays. This is compensated by the robustness of the limited feedback sensing algorithm in the presence of feedback errors (in contrast to the full feedback sensing algorithm) and its modest requirements on the sensed feedback history.

Paterakis, M.; Papantoni-Kazakos, P.

1986-01-01

390

EUV multilayer defect compensation (MDC) by absorber pattern modification: from theory to wafer validation  

NASA Astrophysics Data System (ADS)

According to the ITRS roadmap, mask defects are among the top technical challenges to introduce extreme ultraviolet (EUV) lithography into production. Making a multilayer defect-free extreme ultraviolet (EUV) blank is not possible today, and is unlikely to happen in the next few years. This means that EUV must work with multilayer defects present on the mask. The method proposed by Luminescent is to compensate effects of multilayer defects on images by modifying the absorber patterns. The effect of a multilayer defect is to distort the images of adjacent absorber patterns. Although the defect cannot be repaired, the images may be restored to their desired targets by changing the absorber patterns. This method was first introduced in our paper at BACUS 2010, which described a simple pixel-based compensation algorithm using a fast multilayer model. The fast model made it possible to complete the compensation calculations in seconds, instead of days or weeks required for rigorous Finite Domain Time Difference (FDTD) simulations. Our SPIE 2011 paper introduced an advanced compensation algorithm using the Level Set Method for 2D absorber patterns. In this paper the method is extended to consider process window, and allow repair tool constraints, such as permitting etching but not deposition. The multilayer defect growth model is also enhanced so that the multilayer defect can be "inverted", or recovered from the top layer profile using a calibrated model.

Pang, Linyong; Hu, Peter; Satake, Masaki; Tolani, Vikram; Peng, Danping; Li, Ying; Chen, Dongxue

2011-10-01

391

Invertible temporal subband/wavelet filter banks with half-pixel-accurate motion compensation.  

PubMed

Three-dimensional (3-D) subband/wavelet coding with motion compensation has been demonstrated to be an efficient technique for video coding applications in some recent research works. When motion compensation is performed with half-pixel accuracy, images need to be interpolated in both temporal subband analysis and synthesis stages. The resulting subband filter banks developed in these former algorithms were not invertible due to image interpolation. In this paper, an invertible temporal analysis/synthesis system with half-pixel-accurate motion compensation is presented. We look at temporal decomposition of image sequences as a kind of down-conversion of the sampling lattices. The earlier motion-compensated (MC) interlaced/progressive scan conversion scheme is extended for temporal subband analysis/synthesis. The proposed subband/wavelet filter banks allow perfect reconstruction of the decomposed video signal while retaining high energy compaction of subband transforms. The invertible filter banks are then utilized in our 3-D subband video coder. This video coding system does not contain the temporal DPCM loop employed in the conventional hybrid coder and the earlier MC 3-D subband coders. The experimental results show a significant PSNR improvement by the proposed method. The generalization of our algorithm for MC temporal filtering at arbitrary subpixel accuracy is also discussed. PMID:15326844

Hsiang, Shih-Ta; Woods, John W; Ohm, Jens-Rainer

2004-08-01

392

28 CFR 34.111 - Compensation.  

Code of Federal Regulations, 2013 CFR

... Judicial Administration DEPARTMENT OF JUSTICE OJJDP COMPETITION AND PEER REVIEW PROCEDURES Peer Review § 34.111 Compensation...eligible to be paid according to applicable regulations and policies concerning consulting fees and reimbursement for expenses....

2013-07-01

393

33 CFR 136.205 - Compensation allowable.  

Code of Federal Regulations, 2010 CFR

...Section 136.205 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF...

2013-07-01

394

33 CFR 136.113 - Other compensation.  

Code of Federal Regulations, 2010 CFR

...Section 136.113 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF...

2013-07-01

395

33 CFR 136.235 - Compensation allowable.  

Code of Federal Regulations, 2010 CFR

...Section 136.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF...

2013-07-01

396

33 CFR 136.241 - Compensation allowable.  

Code of Federal Regulations, 2010 CFR

...Section 136.241 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF...

2013-07-01

397

33 CFR 136.223 - Compensation allowable.  

Code of Federal Regulations, 2010 CFR

...Section 136.223 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF...

2013-07-01

398

A simple model of bank employee compensation  

Microsoft Academic Search

This paper considers the question, Does the limited liability associated with banking make it necessary for a government to regulate bank employee compensation? It attempts to shed light on this question by considering a mechanism design framework.

Christopher Phelan

2009-01-01

399

Brain May Recover from Concussion by Compensating  

MedlinePLUS

... page, please enable JavaScript. Brain May Recover From Concussion by Compensating Study found increased brain activity in ... Preidt Friday, August 23, 2013 Related MedlinePlus Pages Concussion Sports Injuries FRIDAY, Aug. 23 (HealthDay News) -- Concussion ...

400

44 CFR 295.21 - Allowable compensation.  

Code of Federal Regulations, 2010 CFR

...amount. Claimants must take reasonable steps to mitigate (reduce) their damages, if possible, as required by New Mexico tort law. (b) Exclusions. Except as otherwise provided in the CGFAA, a Claimant will not receive compensation for...

2007-10-01

401

Highway and Wetlands: Compensating Wetland Losses.  

National Technical Information Service (NTIS)

The implementation package is a practical guide for the creation and restoration of wetlands. It provides concepts, methods and general specifications for compensating unavoidable wetland losses in a cost effective manner. The manual includes guidance for...

E. W. Garbisch

1986-01-01

402

Medical Roles in Workers' Compensation Information Gathering.  

National Technical Information Service (NTIS)

Papers delivered at the 36th AMA Congress on Occupational Health in 1976 are provided. The Symposia topics were medical roles in workers' compensation, basic physician knowledge about radiation, medical recordkeeping and surveillance, interdisciplinary te...

M. L. Amdur

1977-01-01

403

45 CFR 1607.5 - Compensation.  

Code of Federal Regulations, 2011 CFR

...LEGAL SERVICES CORPORATION GOVERNING BODIES § 1607.5 Compensation. (a) While serving on the governing body of a recipient, no attorney member...fees awarded by a court or administrative body or included in a settlement in cases...

2011-10-01

404

Illumination Control Apparatus for Compensating Solar Light.  

National Technical Information Service (NTIS)

An illumination control apparatus for supplementing light from solar radiation with light from an artificial light source was designed to compensate for periods of insufficient levels of solar light to maintain a desired illumination level within an inter...

L. J. Owens

1976-01-01

405

12 CFR 2.5 - Bank compensation.  

Code of Federal Regulations, 2013 CFR

...an affiliate operating under the Bank Holding Company Act of 1956, 12...shareholders, provided that the bank receives reasonable compensation...20 percent of the affiliate's net income attributable to the bank's credit life insurance...

2013-01-01

406

Workers compensation: coverage, benefits, and costs, 1982  

SciTech Connect

Workers compensation provides medical care and income maintenance protection to workers disabled from work-related injury or illness. This program is of considerable interest to the Social Security Administration (SSA) from several perspectives. For example, since 1965 Social Security Disability Insurance (DI) benefits and workers compensation payments have been integrated. Information on the experience under workers compensation provides a framework for examining questions concerning gaps and overlaps in the Nation's social insurance system. In addition, since December 1969 SSA has administered claims filed through 1973 under part B of the Black Lung program--the program providing income maintenance protection to coal miners disabled by pneumoconiosis. The workers compensation experience reported here consists of information on benefits for work-related injury and disease, including data on the combined benefits paid under the entire Federal Black Lung program administered by the Labor Department and SSA.

Price, D.N.

1984-12-01

407

Emergency Unemployment Compensation. CRS Report for Congress.  

National Technical Information Service (NTIS)

The Emergency Unemployment Compensation (EUC) program was created by P.L. 110-252. This new temporary unemployment insurance program provides up to 13 additional weeks of unemployment benefits to certain workers who have exhausted their rights to regular ...

J. M. Whittaker

2008-01-01

408

Temperature Compensated Latching Ferrite Phase Shifter.  

National Technical Information Service (NTIS)

The patent application describes a nonreciprocal latching phase shifter that is compensated for changes in temperature. A pair of ferrite rectangular toroids in series connection are inserted into a rectangular waveguide and a dielectric material is inser...

I. Bardash

1973-01-01

409

Compensation and Teacher Retention: A Success Story.  

ERIC Educational Resources Information Center

Describes components of successful teacher-evaluation and compensation program at the Ladue School District in suburban St. Louis, Missouri. Reports that salary increases based on performance evaluations improve teacher satisfaction and retention. (Contains 13 references.) (PKP)

Morice, Linda C.; Murray, James E.

2003-01-01

410

Comparative Studies in Automobile Accident Compensation.  

National Technical Information Service (NTIS)

The report is a collection of five papers by noted foreign scholars on the automobile accident compensation systems of their respective countries: France, Germany, Great Britain, Sweden, and Canada. The papers focus on problems and reform proposals curren...

A. Tunc W. Pfennigstorf D. R. Harris J. Hellner A. M. Linden

1970-01-01

411

Exempt salary administration. Redesigning staff nurse compensation.  

PubMed

An exempt salary administration program can provide positive benefits for the professional nurses and the hospital, thus creating a "win-win" strategy for today's competitive environment. This compensation change requires careful planning and open discussion between hospital administration and professional nursing staff. In this era of diminishing human and economic resources, selection of nurse compensation programs that mirror the culture and strategic goals of an organization is key to the success of the institution. PMID:1597757

Blouin, A S

1992-06-01

412

Beyond negligence: avoidability and medical injury compensation.  

PubMed

Disenchantment with the tort system and negligence standard in the United States is fueling interest in alternate compensation systems for medical injury. One possibility is experimentation with administrative "health courts," through which specialized adjudicators would utilize neutral experts to render compensability determinations. Compensation would be based not on negligence, but rather on a broader avoidable medical injury (avoidability) standard. Although considerable interest in health courts exists, stakeholders frequently express uncertainty about the meaning and operation of an avoidability standard. Three nations-Sweden, Denmark, and New Zealand-have long operated administrative schemes. We conducted interviews with administrators and stakeholders in these systems. Our goal was to garner lessons on how to operate a health court, and specifically, how to develop and apply alternate compensation criteria such as avoidability. This article reports our findings on the origins and operations of the systems, the evolution of their compensation criteria, and how these criteria are actually applied. We found that all three systems had their primary genesis in ensuring compensation for the injured, as opposed to sanctioning providers. All have abandoned the negligence standard. The Nordic systems use an avoidability standard, principally defined as injury that would not occur in the hands of the best practitioner. Their experience demonstrates that this definition is feasible to apply. New Zealand's recent move to a no-fault system sheds light on the benefits and drawbacks of a variety of compensation standards. Key lessons for successfully applying an alternate standard, such as avoidability, include a strict adherence to national precedent, the use of neutral and experienced experts, and a block on routine transfer of information from compensation investigations to disciplinary authorities. Importantly, all three nations are harnessing their systems' power to improve patient safety, and the avoidability standard appears to be well suited for this task. PMID:17931762

Kachalia, Allen B; Mello, Michelle M; Brennan, Troyen A; Studdert, David M

2007-10-10

413

Compensation and Reparation for Victims of Terrorism  

Microsoft Academic Search

\\u000a As demonstrated in Chapters 3 and 4, terrorism is capable of inflicting widespread personal injury, and unprecedented property\\u000a and financial damage.1 Especially the 9\\/11 aftermath has led to a worldwide academic and political discussion on how to compensate victims of future\\u000a terrorist acts.2 The debate concentrates on (a) the availability of (default) private and public compensation schemes, (b) their mutual

Rianne Letschert; Karin Ammerlaan

2009-01-01

414

Coma compensation in a parabolized Ebert monochromator.  

PubMed

Coma compensation in a parabolized Ebert monochromator is studied using the plate diagram. It is shown that two different criteria may be used: narrowest images or symmetrical ones; however, both may not be satisfied simultaneously. Symmetrical or narrowest images may be obtained for an extended range of wavelengths with displacement of at least one of the slits. With fixed slits only incomplete compensation may be obtained. PMID:20212647

Gil, M A; Simon, J M

1979-07-01

415

Motion compensated video compression using adaptive transformations  

Microsoft Academic Search

Block-based motion compensation fails to maintain an acceptable level of prediction error which makes the transmission of this error impossible for very low bit-rate coding owing to the small bit allocation. The reason is that the motion model assumed in block-based techniques cannot approximate the motion in the real world precisely. To develop an effective motion compensation method for very

Zafer Diab; Paul Cohen

1997-01-01

416

Method of projectile spinning rate processing based on acceleration compensation  

NASA Astrophysics Data System (ADS)

Slotting at the base of spin-stabilized projectile is widely used in spinning rate measurement. Confined by the structure of the base, it only suits few models of projectile. For the projectiles with special structures, such as apertures or holes at the base, the information of spinning rate in radar echo is considerably so weak that the conventional signal processing methods become invalid. Herein, a method based on acceleration compensation is proposed to extract the spinning rate from the echo of low signal to noise rate (SNR). First, an algorithm called Two Segments based FFT is adopted to estimate the coarse rate of linear frequency modulation (LFM). Next, using the coarse rate as the initial value of optimization, Golden Section method is used to search the fine rate of LFM to improve the accuracy of estimation. Then, the fine value is used to construct the reference LFM signal and compensate the effect of acceleration. At last, based on Chirp Z Transform, the method of spectrum zooming is employed to alleviate the spectrum leakage and improve the performance of spinning rate processing. Simulation shows that the precision of the spinning rate measurement is better than 0.25% for majority of the modulation indices when the SNR equals to 0 dB.

Zhang, Ruoyu; Wang, Yuanqin; Sun, Jing

2013-01-01

417

Development of a blended-control, predictor-corrector guidance algorithm for a crewed Mars aerocapture vehicle  

NASA Astrophysics Data System (ADS)

A robust blended-control guidance system for a crewed Mars aerocapture vehicle is developed. The key features of its guidance algorithm are the use of the both bank-angle and angle-of-attack modulation to control the aerobraking vehicle, and the use of multiple controls (sequenced pairs of bank-angles and angles-of-attack) within its numeric predictor-corrector targeting routine. The guidance algorithm macrologic is based on extensive open loop trajectory analyses, described in the present research, which led to the selection of a blended-control scheme. A heuristic approach to recover from situations where no converged guidance solution could be found by the numeric predictor-corrector is implemented in the guidance algorithm, and has been successfully demonstrated in a large number of test runs. In this research both the outer and inner loop of the guidance and control system employ the POST (Program to Optimize Simulated Trajectories) computer code as the basic simulation module. At each guidance update, the inner loop solves the rigorous three-dimensional equations of motion and computes the control (bank-angle and angle-of-attack) sequence that is required to meet the required atmospheric exit conditions. Throughout the aerocapture trajectory, the guidance algorithm modifies this control sequence computed by the inner loop, and generates commanded controls for the vehicle, which, when implemented by the outer loop, meet an imposed g-load constraint of 5 Earth g's and compensate for unexpected off-nominal conditions. This blended-control, predictor-corrector guidance algorithm has been successfully developed, implemented and tested and has been shown to be capable of meeting the prescribed g-load constraint and guiding the vehicle to the desired exit conditions for a range of off-nominal factors much wider than those which could be accommodated by prior algorithms and bank-angle-only guidance.

Jits, Roman Yuryevich

418

Automatic clocking optimization for compensating two-dimensional tolerances.  

PubMed

Clocking of lens elements is frequently used as an effective method of compensating for two-dimensional tolerances such as material inhomogeneity and surface figure errors. Typically, the lens designer has to determine the optimum angles of rotation by manually modeling lens element clocking in the commercial optical design software because the nature of errors resolved by lens clocking does not lead to good convergences for clocking optimization. In this paper, a method of automatic clocking optimization is developed. The method is implemented using a combination of particle swarm optimization algorithm and commercial optical design software. The optimum angles of rotation and predicted imaging performance are automatically calculated using this method. Methods of implementation and optimization examples are also given. PMID:24104106

Xu, Weicai; Huang, Wei; Liu, Chunlai; Shang, Hongbo

2013-09-23

419

37-element adaptive optics experimental system and turbulence compensation experiments  

NASA Astrophysics Data System (ADS)

A 37 element adaptive optics system has been built in the Institute of Optics and Electronics for experimental research of atmospheric effect compensation. In this system a 37 subaperture Shack-Hartmann sensor with frame rate 380 Hz is used as wavefront sensor, a 37/55 element deformable mirror and a fast steering mirror as wavefront correctors, a digital signal processor with peak operation speed 100 Mops as wavefront processor and controller, and 39 channels of high voltage amplifier for controlling the wavefront correctors. This system has been integrated with a turbulence cell developed by the Anhui Institute of Optics and Fine Mechanics and experiments for compensating for wavefront errors induced by the turbulence of the cell with different strength have been conducted. Another Shack- Hartmann wavefront sensor is used for measuring the strength of turbulence. The integrated probability density functions of both the coherence length r(subscript 0) and the Strehl ratio of S of the focused spot are used to describe the strength of turbulence and the sharpness of focused spots with and without correction. In this paper the adaptive optics system and the experimental results are briefly reported.

Jiang, Wenhan; Ling, Ning; Wu, Xubin; Wang, Chenhong; Xian, Hao; Huang, Shufu; Rong, Zhijun; Guan, Chunlin; Jiang, Lingtao; Gong, Zhiben; Wu, Yi; Wang, Yingjian

1996-10-01

420

Standard compensators for ENT therapy fields  

SciTech Connect

Radiotherapy of the ENT region is frequently applied through two parallel-opposed, lateral fields covering a volume from the maxillary sinus to the base of the neck, with the isocentre close to the angle of the mandible. The large variation in separation throughout this volume, in both the transverse and the coronal planes, leads to field inhomogeneities which are often resolved by the use of custom designed, two-dimensional compensators. This paper presents an alternative method of compensation using a set of one-dimensional, standard compensators applied in the coronal plane which, in conjunction with a wedge in the transverse plane, yields a uniform distribution throughout the treatment volume for the majority of patient configurations. The advantages of this technique are the immediate availability of a computerised treatment plan incorporating the compensator, an increase in the dose homogeneity obtainable over that without compensation and the elimination of any delay which may be incurred by the design and fabrication of custom made compensators.

Clark, B.G.; Evans, M.D. (McGill Univ., Quebec (Canada))

1988-12-01

421

On-line nonuniformity and temperature compensation of uncooled IRFPAs using embedded digital hardware  

NASA Astrophysics Data System (ADS)

We present a model and a signal-processing algorithm for compensating the nonuniformity (NU) noise and surrounding temperature self-heating e ects on the response of uncooled microbolometer-based infrared cameras. The model for the NU noise considers pixelwise gain and o set parameters. The representation for the self-heating dynamics of the camera is an autoregressive moving average (ARMA) model for camera's internal temperature. The algorithm performs initially a two-point calibration at a known surrounding temperature. Next, without modifying the NU parameters, we dynamically compensate variations in the camera readout using both estimates of the ARMA model and measurements of the surrounding temperature taken by a simple sensor embedded in the camera. Tested on a CEDIP Jade UC33 camera, our system compensates reference black-body images at 30 degrees Celsius, with a peak error below 1.3 and a mean error below 0.3 degrees Celsius, in scenarios where the room temperature varied up to 14 degrees Celsius. Moreover, the regularity and simplicity of the algorithm enables us to implement it on embedded digital hardware, thereby reducing its cost, size, and power consumption. We implemented the algorithm on a Xilinx XC6SLX45 FPGA using xed-point arithmetic. The circuit exhibits an arithmetic error of 0.06 degrees compared to a software double-precision implementation. It compensates 320 × 240-pixel video at up to 1,437 fps and 640 × 480-pixel video at up to 360 fps, using 1% of the logic resources of the FPGA, and less than 1 mW of dynamic power at 110 MHz. Adding Gigabit Ethernet communication, HDMI display, and a pseudocolor map on the chip uses 10% of the resources and consumes 915 mW.

Wolf, Alejandro; Redlich, Rodolfo; Figueroa, Miguel; Pezoa, Jorge E.

2013-09-01

422

Net-Shape Forging of Aerofoil Blade based on Flash Trimming and Compensation methods  

SciTech Connect

In this research, an automatic blade forging die shape optimisation system was developed by using direct compensation and flash trimming algorithms and integrating with the DEFORM 3D software package. To validate the developed system, a 3D blade forging case problem was simulated and optimised with and without the consideration of trimming simulation. The results were compared with actual measurement data of the forged aerofoil blade with excellent results obtained with the fast trimming simulation procedure used.

Lu, B. [Department of Plasticity Forming Engineering, Shanghai Jiao Tong University, Shanghai, 200030 (China); Ou, H. [Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Armstrong, C. G. [School of Mechanical and Aerospace Engineering, Queen's University Belfast, Belfast, BT9 5AH (United Kingdom)

2011-05-04

423

Net-Shape Forging of Aerofoil Blade based on Flash Trimming and Compensation methods  

NASA Astrophysics Data System (ADS)

In this research, an automatic blade forging die shape optimisation system was developed by using direct compensation and flash trimming algorithms and integrating with the DEFORM 3D software package. To validate the developed system, a 3D blade forging case problem was simulated and optimised with and without the consideration of trimming simulation. The results were compared with actual measurement data of the forged aerofoil blade with excellent results obtained with the fast trimming simulation procedure used.

Lu, B.; Ou, H.; Armstrong, C. G.

2011-05-01

424

An advanced FEA based force induced error compensation strategy in milling  

Microsoft Academic Search

The study introduces a multi-level machining error compensation approach focused on force-induced errors in machining of thin-wall structures. The prediction algorithm takes into account the deflection of the part in different points of the tool path. The machining conditions are modified at each step when the cutting force and deflection achieve a local equilibrium. The machining errors are predicted using

S. Ratchev; S. Liu; W. Huang; A. A. Becker

2006-01-01

425

Motion-Compensated Reconstruction Method Based on Rigid Motion Model with Multi-Object  

Microsoft Academic Search

This paper gives an efficient approach to reconstruct moving multiple objects (multi-object). Each object has independently rigid motion which includes translation and rotation. The traditional FBP algorithm can resolve the one-object motion problem rather well. However, it suffers from perceptible motion artifacts in multi-object cases. This paper proposes a new motion-compensated reconstruction approach with a priori knowledge of the rigid

Xin Jin; Liang Li; Zhiqiang Chen; Li Zhang; Yuxiang Xing

2010-01-01

426

Motion-compensated residue preprocessing in video coding based on just-noticeable-distortion profile  

Microsoft Academic Search

We present a motion-compensated residue signal preprocessing scheme in video coding scheme based on just-noticeable-distortion (JND) profile. Human eyes cannot sense any changes below the JND threshold around a pixel due to their underlying spatial\\/temporal masking properties. An appropriate (even imperfect) JND model can significantly help to improve the performance of video coding algorithms. From the viewpoint of signal compression,

Xiaokang Yang; Weisi Lin; Zhongkhang Lu; Ee Ping Ong; Susu Yao

2005-01-01

427

Motion compensated iterative reconstruction of a region of interest in cardiac cone-beam CT  

Microsoft Academic Search

A method for motion compensated iterative CT reconstruction of a cardiac region-of-interest is presented. The algorithm is an ordered subset maximum likelihood approach with spherically symmetric basis functions, and it uses an ECG for gating. Since the straightforward application of iterative methods to CT data has the drawback that a field-of-view has to be reconstructed, which covers the complete volume

A. A. Isola; A. Ziegler; Dirk Schäfer; Thomas Köhler; Wiro J. Niessen; Michael Grass

2010-01-01

428

The research of moving object detection based on background difference compensation  

NASA Astrophysics Data System (ADS)

Moving object detection was implemented in dynamic background based on background difference compensation. Background differential can effectively segment the moving object in static background. But in moving video, the camera motion causes corresponding movement of the target and background, which makes the prospect moving object hard to separate from the background. In order to detect moving object, we can compensate the movement of the background and transfer the dynamic background to static. Moving object detection in static background image was implemented using a new weights updating method that the weights were updated during a certain period. This method based on classical Gaussian mixture model improved the efficiency of image segmentation greatly. Moving object detection in dynamic background was realized using background differential compensation. The global motion of the background was established according to the affined parameters model. The model parameters were estimated by feature points matching based on the search strategy. Invalid matching points were eliminated using the method of distance consistency. Backward mapping was used to get the motion parameters of the background. After compensation of the background with the global motion parameters, frame difference between the current frame and the background can detect moving objects effectively. Experiments were done on computer with the programming tools of VS2010 and MATLAB. Experimental results showed that the algorithm based on differential compensation was effective.

Song, Yan-bin; Ying, Jie; Lu, Lin-li

2013-08-01

429

Compensation for 3D physiological motion in robotic-assisted surgery using a predictive force controller. Experimental results  

Microsoft Academic Search

This paper presents a predictive force control approach to compensate for the physiological motion induced by both respiratory and heart beating motions during cardiac surgery. It focuses on the design and implementation of the control algorithm in the context of robotized minimally invasive surgery. The controller is based on a linear predictive control loop using the force information applied on

Michel Dominici; Philippe Poignet; Rui Cortesão; Etienne Dombre; Olivier Tempier

2009-01-01

430

Image super-resolution: Iterative multiframe algorithms and training of a nonlinear vector quantizer  

NASA Astrophysics Data System (ADS)

Images acquired by ground-based telescopes are severely degraded by atmospheric turbulence effects. New algorithms are presented for restoration with super-resolution of satellite object images from sequences of turbulence-degraded observations. Super-resolution refers to recovery of Fourier spectral components outside the optical system passband. Modern wave front sensor (WFS) can measure the optical distortions caused by the atmosphere. Such measurement can be used for (1) control of an adaptive optics (AO) system; (2) for post-processing of the uncompensated image; and (3) for a hybrid approach involving partially compensated images. This study focuses on the second of these approaches. Quantitative simulation of imaging through turbulence and WFS are used to demonstrate the performance of new super-resolving multiframe algorithms based on Bayes maximum a posteriori (MAP) criterion. The original and object images are assumed to have Poisson statistics. The resulting Poisson MAP algorithms extend the single frame version to the multiframe case. Super-resolution is demonstrated for realistic conditions. In the blind deconvolution problem, both the original image and the degradations must be derived simultaneously from the recorded images without the aid of WFS. We investigate this problem and propose a new multiframe algorithm based on Bayes maximum likelihood. Strict constraints such as positivity and finite bandwidth are incorporated using nonlinear reparameterizations. Nonlinear conjugate gradient techniques are employed along with implementation on the massively parallel IBM SP2, in order to meet the computational demands of these algorithms. Super-resolution is demonstrated for realistic circumstances. On a related subject, nonlinear interpolative vector quantization (NLIVQ) is presented as a tool for the novel application of vector quantization (VQ) to super-resolution of diffraction-limited images. The algorithm is trained on a large set of image pairs, consisting of an original and its diffraction-limited counterpart, and exploits the statistical dependence between blocks of pixels in the two images. The discrete cosine transform (DCT) is used to manage the codebook complexity and simplify training. Simulation results are presented which demonstrate improvements in the visual quality and peak signal-to-noise ratio. A study of restored image spectra reveals modest super-resolution. The prospects for this technique are promising.

Sheppard, David Glen

431

Genetic Algorithms  

Microsoft Academic Search

\\u000a Genetic algorithms (GAs) have become popular as a means of solving hard combinatorial optimization problems. The first part\\u000a of this chapter briefly traces their history, explains the basic concepts and discusses some of their theoretical aspects.\\u000a It also references a number of sources for further research into their applications. The second part concentrates on the detailed\\u000a implementation of a GA.

Colin R. Reeves

432

Simulation of atmospheric turbulence layers with phase screens by JAVA  

NASA Astrophysics Data System (ADS)

In multiconjugate Adaptive Optics (MCAO), the phase screens are used to simulate atmospheric turbulence layers to study the optimal turbulence delamination and the determination of layer boundary position. In this paper, the method of power spectrum inversion and sub-harmonic compensation were used to simulate atmospheric turbulence layers and results can be shown by grey map. The simulation results showed that, with the increase of turbulence layers, the RMS of adaptive system decreased, but the amplitude diminished. So the atmospheric turbulence can be split into 2-3 layers and be modeled by phase screens. Otherwise, a small simulation atmospheric turbulence delamination system was realized by JAVA.

Zhang, Xiaofang; Chen, Wenqin; Yu, Xin; Yan, Jixiang

2008-03-01

433

Atmospheric radiation  

SciTech Connect

Studies of atmospheric radiative processes are summarized for the period 1987-1990. Topics discussed include radiation modeling; clouds and radiation; radiative effects in dynamics and climate; radiation budget and aerosol effects; and gaseous absorption, particulate scattering and surface reflection. It is concluded that the key developments of the period are a defining of the radiative forcing to the climate system by trace gases and clouds, the recognition that cloud microphysics and morphology need to be incorporated not only into radiation models but also climate models, and the isolation of a few important unsolved theoretical problems in atmospheric radiation.

Harshvardhan, M.R. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

1991-01-01

434

Automatic time gain compensation and dynamic range control in ultrasound imaging systems  

NASA Astrophysics Data System (ADS)

For efficient and accurate diagnosis of ultrasound images, the appropriate time gain compensation (TGC) and dynamic range (DR) control of ultrasound echo signals are important. TGC is used for compensating the attenuation of ultrasound echo signals along the depth, and DR is for controlling the image contrast. In recent ultrasound systems, those two factors are automatically set by a system and/or manually adjusted by an operator to obtain the desired image quality on the screen. In this paper, we propose an algorithm to find the optimized parameter values for TGC and DR automatically. In TGC optimization, we determine the degree of attenuation compensation along the depth by reliably estimating the attenuation characteristic of ultrasound signals. For DR optimization, we define a novel cost function by properly using the characteristics of ultrasound images. Experimental results are obtained by applying the proposed algorithm to a real ultrasound (US) imaging system. The results prove that the proposed algorithm automatically sets values of TGC and DR in real-time so that the subjective quality of the enhanced ultrasound images may become good enough for efficient and accurate diagnosis.

Lee, Duhgoon; Kim, Yong Sun; Ra, Jong Beom

2006-03-01

435

20 CFR 10.416 - How does a change in the number of beneficiaries affect the amount of compensation paid to the...  

Code of Federal Regulations, 2013 CFR

...OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL EMPLOYEES' COMPENSATION ACT, AS AMENDED Compensation and Related Benefits Compensation...

2013-04-01

436

Compensation of victims of interpersonal violence in Hessen\\/Germany  

Microsoft Academic Search

A research project on the German Victim Compensation Act (OEG). In cooperation with the Hesse Maintenance Council and Fulda County (October 2009 to September 2010). Since March 2007, there is an European agreement on the compensation of victims of interpersonal violence. Despite this agreement the national Victim Compensation Acts differ in extend of and criteria for compensation. The OEG was

B Blttner; A Grundel

2010-01-01

437

Takings, Compensation and Endangered Species Protection on Private Lands  

Microsoft Academic Search

Preserving endangered species on private land benefits the public, but may confer cost on landowners if property is 'taken.' Government compensation to landowners can offset costs, although the Endangered Species Act does not require compensation. The authors survey private economic incentives for species preservation created by alternative property rights and compensation regimes. Compensation will effect investments in land and the

Robert Innes; Stephen Polasky; John Tschirhart

1998-01-01

438

STATCOM for compensation of large electric arc furnace installations  

Microsoft Academic Search

High power electronic equipment, developed for the compensation of utility power transmission systems, has been successfully applied to the problem of flicker compensation in a large industrial arc furnace. Whereas conventional flicker compensation methods, using thyristor valves in conjunction with passive components, have generally failed to reduce flicker substantially the new STATCOM-based compensator provides a dramatic reduction in flicker, as

C. Schauder

1999-01-01

439

Freebal: dedicated gravity compensation for the upper extremities  

Microsoft Academic Search

In most upper-extremity rehabilitation robotics, several components affect the therapy outcome. A common component is gravity compensation which alleviates upper-extremity movements. Gravity compensation by itself could improve motor control further or faster, separate from other effects of robotic therapy. To investigate the rehabilitation value of gravity compensation separately, we created the dedicated gravity compensation system, Freebal. The sling systems with

Amo H. A. Stienen; E. E. G. Hekman; G. B. Prange; M. J. A. Jannink; A. M. M. Aalsma; H. Van der Kooij

2007-01-01

440

Robust control algorithms for Mars aerobraking  

NASA Astrophysics Data System (ADS)

Four atmospheric guidance concepts have been adapted to control an interplanetary vehicle aerobraking in the Martian atmosphere. The first two offer improvements to the Analytic Predictor Corrector (APC) to increase its robustness to density variations. The second two are variations of a new Liapunov tracking exit phase algorithm, developed to guide the vehicle along a reference trajectory. These four new controllers are tested using a six degree of freedom computer simulation to evaluate their robustness. MARSGRAM is used to develop realistic atmospheres for the study. When square wave density pulses perturb the atmosphere all four controllers are successful. The algorithms are tested against atmospheres where the inbound and outbound density functions are different. Square wave density pulses are again used, but only for the outbound leg of the trajectory. Additionally, sine waves are used to perturb the density function. The new algorithms are found to be more robust than any previously tested and a Liapunov controller is selected as the most robust control algorithm overall examined.

Shipley, Buford W., Jr.; Ward, Donald T.

441

Temperature Compensation in Two Centrarchid Fishes: Do Winter-Quiescent Fish Undergo Cellular Temperature Compensation?  

Microsoft Academic Search

Cellular temperature compensation of green sunfish Lepomis cyanellus, a species active in cold water, was compared to that of the cofamilial smallmouth bass Micropterus dolomieui, a species quiescent in cold water. It was hypothesized that there would be a correlation between degree of cellular temperature compensation and degree of coldwater activity for these two centrarchids. Fishes were acclimated to 5,

Alan S. Kolok

1991-01-01

442

20 CFR 10.422 - May compensation payments be issued in a lump sum?  

Code of Federal Regulations, 2013 CFR

...OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL EMPLOYEES' COMPENSATION ACT, AS AMENDED Compensation and Related Benefits Adjustments to...

2013-04-01

443

20 CFR 10.425 - May compensation be claimed for periods of restorable leave?  

Code of Federal Regulations, 2013 CFR

...DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL EMPLOYEES' COMPENSATION ACT, AS AMENDED Compensation...restorable leave? The employee may claim compensation for periods of...

2013-04-01

444

20 CFR 10.423 - May compensation payments be assigned to, or attached by, creditors?  

Code of Federal Regulations, 2013 CFR

...OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL EMPLOYEES' COMPENSATION ACT, AS AMENDED Compensation and Related Benefits Adjustments to...

2013-04-01

445

Extraction algorithms for cortical control of arm prosthetics  

Microsoft Academic Search

Now that recordings of multiple, individual action potentials are being made with chronic electrodes, it seems that previous work showing simple encoding of movement parameters in these spike trains can be used as a real-time control signal for prosthetic arms. Efficient extraction algorithms can compensate for the limited ensemble sample acquired with this emerging technology.

Andrew B Schwartz; Dawn M Taylor; Stephen I. Helms Tillery

2001-01-01

446

[Occupational cancers: notification, compensation and prevention].  

PubMed

Less than 140 occupational cancers (OC) are compensated every year in France although the incidence is estimated for at least 6,000 new cases, as estimated by the epidemiologists (4% of the mortality by cancers). This situation can be explained by different factors: few compensation claims by the patients or families, frequent lack of interest from medical doctors for relation between cancer and work, occurrence of the OC after retirement, difficulty to distinguish the role of occupational factors from individual comportmental factors in many OC (for ex. a lung cancer hitting a smoker). The consequences of such a situation are multiple: no compensation for more than 95% of patients or relatives, taking for granted that OC is a minor problem, insufficient prevention of the carcinogenic factors on the work place, prevention of cancers restricted to individual comportmental changes. Physicians working in cancerology units have to incite their patients in notifying the OC and help them in compensation claims. They have also to ask for epidemiologic and toxicologic research when clusters of OC are identified in a plant, in order to get better prevention, compensation and regulations. PMID:7949579

Brugère, J; Thébaud-Mony, A; Pézerat, H; Cassou, B

1994-01-01

447

Temperature compensation and entrainment in circadian rhythms.  

PubMed

To anticipate daily variations in the environment and coordinate biological activities into a daily cycle many organisms possess a circadian clock. In the absence of external time cues the circadian rhythm persists with a period of approximately 24?h. The clock phase can be shifted by single pulses of light, darkness, chemicals, or temperature and this allows entrainment of the clock to exactly 24 h by cycles of these zeitgebers. On the other hand, the period of the circadian rhythm is kept relatively constant within a physiological range of constant temperatures, which means that the oscillator is temperature compensated. The mechanisms behind temperature compensation and temperature entrainment are not fully understood, neither biochemically nor mathematically. Here, we theoretically investigate the interplay of temperature compensation and entrainment in general oscillatory systems. We first give an analytical treatment for small temperature shifts and derive that every temperature-compensated oscillator is entrainable to external small-amplitude temperature cycles. Temperature compensation ensures that this entrainment region is always centered at the endogenous period regardless of possible seasonal temperature differences. Moreover, for small temperature cycles the entrainment region of the oscillator is potentially larger for rectangular pulses. For large temperature shifts we numerically analyze different circadian clock models proposed in the literature with respect to these properties. We observe that for such large temperature shifts sinusoidal or gradual temperature cycles allow a larger entrainment region than rectangular cycles. PMID:22683844

Bodenstein, C; Heiland, I; Schuster, S

2012-06-08

448

Temperature compensation and entrainment in circadian rhythms  

NASA Astrophysics Data System (ADS)

To anticipate daily variations in the environment and coordinate biological activities into a daily cycle many organisms possess a circadian clock. In the absence of external time cues the circadian rhythm persists with a period of approximately 24?h. The clock phase can be shifted by single pulses of light, darkness, chemicals, or temperature and this allows entrainment of the clock to exactly 24 h by cycles of these zeitgebers. On the other hand, the period of the circadian rhythm is kept relatively constant within a physiological range of constant temperatures, which means that the oscillator is temperature compensated. The mechanisms behind temperature compensation and temperature entrainment are not fully understood, neither biochemically nor mathematically. Here, we theoretically investigate the interplay of temperature compensation and entrainment in general oscillatory systems. We first give an analytical treatment for small temperature shifts and derive that every temperature-compensated oscillator is entrainable to external small-amplitude temperature cycles. Temperature compensation ensures that this entrainment region is always centered at the endogenous period regardless of possible seasonal temperature differences. Moreover, for small temperature cycles the entrainment region of the oscillator is potentially larger for rectangular pulses. For large temperature shifts we numerically analyze different circadian clock models proposed in the literature with respect to these properties. We observe that for such large temperature shifts sinusoidal or gradual temperature cycles allow a larger entrainment region than rectangular cycles.

Bodenstein, C.; Heiland, I.; Schuster, S.

2012-06-01

449

Peer group ties and executive compensation networks.  

PubMed

Publicly traded firms in the US typically determine C.E.O. compensation by benchmarking the pay of their C.E.O.s against the pay of C.E.O.s in "peer" firms. Consequently, executive compensation is influenced not only by firm-level characteristics, but also by the selection and actions of the firm's immediate peers as well as by the structure of the executive compensation network overall. Analyzing compensation peer group choices made by the same 1183 firms for F.Y. 2007, 2008 and 2009, we find that while the typical compensation peer is similar in size and industry to the firm that chose it, deviations from this norm are common, especially among larger firms, and tend to be towards larger firms with better paid CEOs. Further analysis shows that firms who pay CEOs well relative to the pay that would be predicted from their revenues, return on assets, and industry tend to have greater aspiration bias in their group of named peers. PMID:24090860

Pittinsky, Matthew; Diprete, Thomas A

2013-07-31

450

Development of infrared interferometry for upper atmospheric emission studies.  

PubMed

This paper is a review of the historical development of the Michelson interferometer into modern-day Fourier transform spectrometry (FTS) used for upper atmospheric emission studies in the near IR. For the period of the last decade, the focus of the review is upon USAF/USU interferometric instruments. Michelson invented the "cross beam" interferometer in 1880; however, the first interferogram was not reported until that of Wood in 1911. Fellgett deduced the multiplex advantage in 1949. By the early 1950s, both Jacqui-not and Rupert had pointed out the throughput advantage, and Fellgett and Strong had each obtained Fourier transforms of interferograms. In 1959, J. Connes and Gush obtained a spectrum of the nighttime IR airglow in 30 min using a Michelson interferometer. In 1962 Gush and Buijs flew an interferometer aboard a balloon to obtain spectra from the airglow. Mertz and M. Block developed a commercial Michelson interferometer in about 1959. L. Block of AFCRL flew a Michelson interferometer aboard a satellite in 1962. In 1965, Connes and Connes obtained high-resolution spectra of planets using cat's-eye retroreflectors coupled with an interferometrically controlled step and integrate method. NASA successfully flew an interferometer aboard a satellite in 1969, which led to including FTS experiments on the planetary probes. In 1965 Tukey and Cooley published their FFT computer program based upon the algorithm of Good. AFGL/USU applied the FFT algorithm to FTS that same year. Stair launched a rocketborne liquid-He cooled interferometer in 1976 which obtained spectra of earth limb emissions. Mertz in 1959 approached field-of-view widening of an interferometer using variable thickness glass compensator plates. Baker and his USU staff used the Connes-Bouchareine compensation method to develop a series of wide-angle Michelson interferometers (WAMIs) for airglow and auroral studies. In 1973, they created a cryogenic WAMI to obtain an IR airglow spectrum in only 10 sec. A rocketborne version was successfully flown to obtain airglow spectra in 1979. This instrument took a 2-cm(-1) interferogram in 1 sec., used a liquid-He cooled detector to cover the 2-8-microm range, and the NESR was 3 x 10(-13) W cm(-2) sr(-1)/cm(-1) at 5 microm. PMID:20332829

Baker, D; Steed, A; Stair, A T

1981-05-15

451

Chemical transport modeling of potential atmospheric CO 2 sinks  

Microsoft Academic Search

The potential for carbon dioxide (CO2) sequestration via engineered chemical sinks is investigated using a three dimensional chemical transport model (CTM). Meteorological and chemical constraints for flat or vertical systems that would absorb CO2 from the atmosphere, as well as an example chemical system of calcium hydroxide (Ca(OH)2) proposed by Elliott et al. [Compensation of atmospheric CO2 buildup through engineered

N. A. C. Johnston; D. R. Blake; F. S. Rowland; S. Elliott; K. S. Lackner; H. J. Ziock; M. K. Dubey; H. P. Hanson; S. Barr

2003-01-01

452

TIME-DEPENDENT FACTORS INHERENT IN THE AGE EQUATION FOR DETERMINING RESIDENCE TIMES OF GROUNDWATER USING 14C: A PROCEDURE TO COMPENSATE FOR THE PAST VARIABILITY OF 14C IN ATMOSPHERIC CARBON DIOXIDE, WITH APPLICATION TO THE WAIRAU DEEP AQUIFER, MARLBOROUGH, NEW ZEALAND  

Microsoft Academic Search

The radiocarbon concentration of dissolved inorganic carbon in groundwater is most logically and completely represented as the product of 5 time-variable factors; these are mutually independent, and all must be considered and evalu- ated to determine a groundwater residence time. In the case of one factor, the 14C\\/(12C+13C) ratio of atmospheric CO2, its time variability can be side-stepped by assuming

Claude B Taylor

453

Tolerance design of closed-loop controllers for DC-DC voltage regulators: genetic algorithms and vertex analysis based optimization  

Microsoft Academic Search

In this paper nominal and tolerance design of feedback compensation networks for DC-DC switching converters is presented. Tolerance design techniques, previously presented by the authors and briefly summarized in this paper, are adopted to achieve an optimal design of the compensation network. A genetic algorithm seeks for the set of commercial parameters and tolerance values or the RC components such

N. Femia; G. Spagnuolo

2002-01-01

454

Multilevel ant colony algorithm for optimal placement of capacitors in distribution systems  

Microsoft Academic Search

An ant colony algorithm is proposed to determine the optimal locations and ratings of capacitors in a distribution network for reactive power compensation. The approach is multilevel. Two separate tables of pheromones are maintained by the algorithm. Ants generate solution stochastically, based on these pheromone tables. The pheromone tables are updated periodically, so that pheromones accrue more along better solutions.

Rajeev Annaluru; Sanjoy Das; A. Pahwa

2004-01-01

455

A post-processing algorithm to reduce metallic clip artifacts in CT images  

Microsoft Academic Search

Computed tomography images of cross sections containing metallic implants, such as prosthetic devices or tooth fillings, often have severe artifacts. Such artifacts may hinder medical diagnosis. We present an algorithm to reduce these artifacts. The algorithm involves the convolution back projection and its adjoint, the forward projection. It has two phases — the first phase is a crude correction compensating

Heang K. Tuy

1993-01-01

456

Estimation of IMU and MARG orientation using a gradient descent algorithm  

Microsoft Academic Search

This paper presents a novel orientation algorithm designed to support a computationally efficient, wearable inertial human motion tracking system for rehabilitation applications. It is applicable to inertial measurement units (IMUs) consisting of tri-axis gyroscopes and accelerometers, and magnetic angular rate and gravity (MARG) sensor arrays that also include tri-axis magnetometers. The MARG implementation incorporates mag- netic distortion compensation. The algorithm

Sebastian O. H. Madgwick; Andrew J. L. Harrison; Ravi Vaidyanathan

2011-01-01

457

Optimal design of SSSC damping controller to improve power system dynamic stability using modified intelligent algorithms  

Microsoft Academic Search

In this paper, A modified intelligent Particle Swarm Optimization (PSO) and continuous Genetic Algorithms (GA) have been used for optimal selection of the static synchronous series compensator (SSSC) damping controller parameters in order to improve power system dynamic response and its stability. Then the performance of these methods on system stability has been compared. First intelligent PSO and genetic algorithms

S. Khani; M. Sadeghi; S. H. Hosseini

2010-01-01

458

Compromising algorithmicity and plasticity in autonomous agent control architectures : The autonomous cell  

Microsoft Academic Search

While algorithmic autonomous agent control architectures demonstrate high efficiency, they suffer from network structure rigidity that shows in the liability to crucial errors. On the other hand, the redundancy inherent i n most connectionist architectures allows for continuous s elf-organization that compensates for limited scale local neuron failures. In this article, we a re investigating the relation between algorithmicity and

Elpida Tzafestas

1995-01-01

459

Compensation for the intrinsic dynamics of the InMotion2 robot.  

PubMed

The InMotion2 and other similarly designed robots, are commonly used for rehabilitation of neurological injuries and motor adaptation studies. These robots are used to simulate haptic environments; however, anisotropy in end-point impedance due to the intrinsic robot dynamics can compromise these experiments. The goal was to decrease the magnitude and anisotropy of the robot impedance using a dynamic compensation algorithm that reduces the forces normally felt by the user during rapid movements. We tested this algorithm with two different methods for real-time calculation of derivatives, a novel quadratic fit method (CQF) and the commonly used backward derivative method (CBD). Six subjects performed a series of point-to-point movements under three conditions (no compensation, CQF, CBD), in different directions at peak speeds of 50, 100 and 150 cm/s. Without compensation, tangential peak-to-peak forces were as large as 69 N in certain directions at the 150 cm/s speed. Both CQF and CBD significantly reduced tangential forces in all directions and speeds. CQF outperformed CBD in the directions with highest intrinsic impedance, reducing tangential forces by 64% in these directions. Compensation also significantly reduced forces normal to the movement direction, with CQF again outperforming CBD in several cases. Anisotropy was assessed by the range of tangential peak-to-peak forces across movement directions. In the no compensation condition, anisotropy was as high as 52.7 N at the 150 cm/s speed, but an average anisotropy reduction of 74% was achieved with CQF. The CQF method can significantly reduce impedance and anisotropy in this class of robot. PMID:23313756

Nguyen, Hoi B; Lum, Peter S

2013-01-11

460

Automatic estimation and compensation of geometric distortions in video copies  

NASA Astrophysics Data System (ADS)

The proliferation of pirate copies of feature films on peer-to-peer networks arouses a great interest to countermeasures such as the insertion of (invisible) forensic marks in projected movies, to deter their illegal capture. The registration of pirate copies with the original content is however a prerequisite to the recovery of such embedded messages, as severe geometric distortions often occur in illegally camcorded contents. After a brief state-of-the-art in image registration, the paper details an algorithm for video registration, focusing on the compensation of geometric distortions. Control points are automatically extracted in original and copy pictures, followed by pre- and post-matching filtering steps to discard not relevant control points and erroneous matched pairs of control points respectively. This enables the accurate numerical estimation of an 8-parameter homographic distortion model, used to register the copy frames with the original reference grid. Such an image registration algorithm is inserted into a general video registration scheme. Results are presented on both natural and synthetic test material.

Chupeau, B.; Massoudi, A.; Lefèbvre, F.

2007-01-01

461

Passive Limitations for a Magnetic Gravity Compensator  

NASA Astrophysics Data System (ADS)

The development of sophisticated advanced vibration isolation is important because even the minutest vibrations have disastrous effects on the performance of static and moving parts in high-precision machines. This paper concerns with the isolation of these vibrations for a large static body in an advanced micro-lithographic system, where a passive/active electromagnetic solution is presented. In these configurations passive permanent magnets (PM) provide the gravity compensation and active electromagnets the accurate positioning. This paper only considers the applicability of a passive magnetic solution for this high force gravity compensation application, or, more specifically, the influence of various PM array topologies on the force density. Further, fast-solving analytical models are presented and consequently are used to illustrate the feasibility of using passive permanent magnets for gravity compensation in this demanding high precision industrial application.

Janssen, Jeroen L. G.; Paulides, Johannes J. H.; Lomonova, Elena A.

462

Active magnetic compensation composed of shielding panels.  

PubMed

Magnetically shielded rooms (MSRs) with materials of high permeability and active shield systems have been used to shield magnetic noise for biomagnetic measurements up to now. However, these techniques have various disadvantages. Therefore, we have developed a new shielding system composed of shielding panels using an active compensation technique. In this study, we evaluated the shielding performance of several unit panels attached together. Numerical and experimental approaches indicated that the shielding factor of a cubic model composed of 24 panels was 17 for uniform fields, and 7 for disturbances due to car movement. Furthermore, the compensation space is larger than that of an ordinary active system using large coils rather than panels. Moreover, the new active compensation system has the important advantage that panels of any shape can be assembled for occasional use because the unit panels are small and light. PMID:16012696

Kato, K; Yamazaki, K; Sato, T; Haga, A; Okitsu, T; Muramatsu, K; Ueda, T; Kobayashi, K; Yoshizawa, M

2004-11-30

463

Sources of compensation in hadronic calorimeters  

NASA Astrophysics Data System (ADS)

Monte Carlo simulations are presented using the CALOR code system to study the design of a large hybrid hadron calorimeter system employing a warm liquid active medium (tetramethylsilane, Si(CH3)4) and uranium plates in addition to a conventional Fe/plastic system. In the system described here, the uranium provides partial compensation by suppressing the electromagnetic cascade produced by incident electrons due to sampling inefficiencies. The results of the simulations also indicate that significant compensation is achieved (given small enough saturation) due to low energy recoil protons produced in collisions with low energy (1-20 MeV) cascade and fission neutrons in the active medium. Both compensation mechanisms are important to help balance the response of a calorimeter to incident electrons and hadrons, that is, to achieve a ratio of pulse heights (e/h ~ 1) which will lead to th best energy resolution. Department of Physics, Harvard University, Cambridge, MA 02138, USA.

Goodman, M. S.; Gabriel, T. A.; di Ciaccio, A.; Wilson, R.

1989-06-01

464

Reexamining workers' compensation: a human rights perspective.  

PubMed

Injured workers, particularly those with more severe injuries, have long experienced workers' compensation systems as stressful and demeaning, have found it difficult to obtain benefits, and, when able to obtain benefits, have found them inadequate. Moreover, the last two decades have seen a substantial erosion of the protections offered by workers' compensation. State after state has erected additional barriers to benefit receipt, making the workers' compensation experience even more difficult and degrading. These changes have been facilitated by a framing of the political debate focused on the free market paradigm, employer costs, and worker fraud and malingering. The articles in this special issue propose an alternate framework and analysis, a human rights approach, that values the dignity and economic security of injured workers and their families. PMID:22570018

Boden, Leslie I

2012-06-01

465

Atmospheric Modeling  

Microsoft Academic Search

\\u000a Air quality models simulate the atmospheric concentrations and deposition fluxes to the Earth’s surface of air pollutants\\u000a by solving the mass conservation equations that represent the emissions, transport, dispersion, transformations and removal\\u000a of those air pollutants and associated chemical species. Contemporary air quality models can be grouped into two major categories:\\u000a (1) models that calculate the concentrations of air pollutants

Christian Seigneur; Robin Dennis

466

Atmospheric Processes  

Microsoft Academic Search

\\u000a Atmosphere is the most dynamic part of the terrestrial environment. It is driven by the energy received from the sun. Almost\\u000a all weather phenomena mentioned in Chapter 2 result from the differences in the amount of solar energy received and utilization\\u000a thereof. It is, therefore, necessary to understand as to how the energy from the sun is converted into heat

Pukh Raj Rakhecha; Vijay P. Singh

467

Atmospheric Acoustics  

NASA Astrophysics Data System (ADS)

This chapter deals with sound propagation in the atmosphere, which is an important link in the functional chain from noise emissions from aircraft, road and rail vehicles, and wind turbines to noise perception. The principle processes in outdoor sound propagation are explained. They include refraction, diffraction, and reflection. Two sound propagation models for scientific applications are briefly outlined. Finally, three illustrative applications and their results are discussed.

Heimann, Dietrich; Schady, Arthur; Feng, Joseph

468

The Atmosphere  

NSDL National Science Digital Library

The lessons at this website were prepared to introduce 5th-8th grade students to the fundamental principles of the earth's atmosphere: history, composition, and structure. Includes three pages of information and features to allow for exploration and expansion of current knowledge. In addition, there are four activities to develop performance skills, not only in science, but in math and language arts as well. Links to external sites also included.

469

Earth Tide Algorithms for the OMNIS Computer Program System.  

National Technical Information Service (NTIS)

This report presents five computer algorithms that jointly specify the gravitational action by which the tidal redistributions of the Earth's masses perturb satellite motion. Covered are the perturbing effects of the lunar and solar atmospheric tide bulge...

W. J. Groeger

1986-01-01

470

Efficient Geolocation of InSAR Images from Motion Compensation Processors  

NASA Astrophysics Data System (ADS)

We present an efficient and closed-form algorithm for the geolocation of InSAR images resulting from data processors using motion compensation methods in which the known orbits are corrected and processed to a circular arc reference track. We outline here a derivation utilizing the SCH coordinate system, although our approach may be readily applied to any such processor with suitable changes in coordinate definitions. Motion compensation has been traditionally employed in airborne systems, where the instability of the aircraft trajectories presents issues in the accuracy of the processed phase. However, we have found that motion compensation techniques allowing precise output pixel location are useful in both airborne and spaceborne systems; thus, we present an approach that exploits the simplicity of a properly chosen motion compensation reference geometry. Assuming a circular reference track, we develop a closed form set of equations relating the position of a given DEM pixel to that of the radar. Once position and slant-range are known along the reference arc, we interpolate into the uniformly spaced radar image, avoiding the use of computationally intensive irregular interpolation algorithms. Hence, the resulting equations are simple and lead to a solution that is remarkably fast without sacrificing precision. We demonstrate results from the ALOS platform, validated against the set of corner reflectors deployed by the Jet Propulsion Laboratory at the Rosamond Calibration Array outside of Palmdale, California. Here we see ground projection errors with accuracy on the order of less than a pixel (< 15 m). In addition, we present an extension to our algorithm where the processed Doppler centroid has known range-dependence but with no simple functional form. To accommodate this most general case, we must replace the closed-form equations with an iterative solution. We illustrate these results using data from the NASA/JPL UAVSAR sensor, where we see fast convergence in no more than five iterations.

Wortham, C.; Zebker, H. A.

2010-12-01

471

Motion compensation for fully 4D PET reconstruction using PET superset data.  

PubMed

Fully 4D PET image reconstruction is receiving increasing research interest due to its ability to significantly reduce spatiotemporal noise in dynamic PET imaging. However, thus far in the literature, the important issue of correcting for subject head motion has not been considered. Specifically, as a direct consequence of using temporally extensive basis functions, a single instance of movement propagates to impair the reconstruction of multiple time frames, even if no further movement occurs in those frames. Existing 3D motion compensation strategies have not yet been adapted to 4D reconstruction, and as such the benefits of 4D algorithms have not yet been reaped in a clinical setting where head movement undoubtedly occurs. This work addresses this need, developing a motion compensation method suitable for fully 4D reconstruction methods which exploits an optical tracking system to measure the head motion along with PET superset data to store the motion compensated data. List-mode events are histogrammed as PET superset data according to the measured motion, and a specially devised normalization scheme for motion compensated reconstruction from the superset data is required. This work proceeds to propose the corresponding time-dependent normalization modifications which are required for a major class of fully 4D image reconstruction algorithms (those which use linear combinations of temporal basis functions). Using realistically simulated as well as real high-resolution PET data from the HRRT, we demonstrate both the detrimental impact of subject head motion in fully 4D PET reconstruction and the efficacy of our proposed modifications to 4D algorithms. Benefits are shown both for the individual PET image frames as well as for parametric images of tracer uptake and volume of distribution for (18)F-FDG obtained from Patlak analysis. PMID:20601774

Verhaeghe, J; Gravel, P; Mio, R; Fukasawa, R; Rosa-Neto, P; Soucy, J-P; Thompson, C J; Reader, A J

2010-07-05

472

Motion compensation for fully 4D PET reconstruction using PET superset data  

NASA Astrophysics Data System (ADS)

Fully 4D PET image reconstruction is receiving increasing research interest due to its ability to significantly reduce spatiotemporal noise in dynamic PET imaging. However, thus far in the literature, the important issue of correcting for subject head motion has not been considered. Specifically, as a direct consequence of using temporally extensive basis functions, a single instance of movement propagates to impair the reconstruction of multiple time frames, even if no further movement occurs in those frames. Existing 3D motion compensation strategies have not yet been adapted to 4D reconstruction, and as such the benefits of 4D algorithms have not yet been reaped in a clinical setting where head movement undoubtedly occurs. This work addresses this need, developing a motion compensation method suitable for fully 4D reconstruction methods which exploits an optical tracking system to measure the head motion along with PET superset data to store the motion compensated data. List-mode events are histogrammed as PET superset data according to the measured motion, and a specially devised normalization scheme for motion compensated reconstruction from the superset data is required. This work proceeds to propose the corresponding time-dependent normalization modifications which are required for a major class of fully 4D image reconstruction algorithms (those which use linear combinations of temporal basis functions). Using realistically simulated as well as real high-resolution PET data from the HRRT, we demonstrate both the detrimental impact of subject head motion in fully 4D PET reconstruction and the efficacy of our proposed modifications to 4D algorithms. Benefits are shown both for the individual PET image frames as well as for parametric images of tracer uptake and volume of distribution for 18F-FDG obtained from Patlak analysis.

Verhaeghe, J.; Gravel, P.; Mio, R.; Fukasawa, R.; Rosa-Neto, P.; Soucy, J.-P.; Thompson, C. J.; Reader, A. J.

2010-07-01

473

Space charge compensation in laser particle accelerators  

NASA Astrophysics Data System (ADS)

Laser particle acceleration (LPA) involves the acceleration of particle beams by electromagnetic waves with relatively short wavelength compared with conventional radio-frequency systems. These short length scales raise the question whether space charge effects may be a limiting factor in LPA performance. This is analyzed in two parts of an accelerator system, the acceleration sections and the drift region of the prebuncher. In the prebuncher, space charge can actually be converted to an advantage for minimizing the energy spread. In the accelerator sections, the laser fields can compensate for space charge forces, but the compensation becomes weaker for high beam energy.

Steinhauer, L. C.; Kimura, W. D.

1999-07-01

474

Gamma compensated, self powered neutron detector  

DOEpatents

An improved, self-powered, gamma compensated, neutron detector having two electrically conductive concentric cylindrical electrodes and a central rod emitter formed from a material which emits beta particles when bombarded by neutrons. The outer electrode and emitter are maintained at a common potential and the neutron representative current is furnished at the inner cylindrical electrode which serves as a collector. The two concentric cylindrical electrodes are designed to exhibit substantially equal electron emission induced by Compton scattering under neutron bombardment to supply the desired gamma compensation.

Brown, Donald P. (Richland, WA)

1977-01-01

475

Skew quad compensation for SPEAR minibeta optics  

SciTech Connect

With the new minibeta insertion for SPEAR the betatron coupling and the perturbations of beam optics caused by the solenoid field of the MARK III detector can't be compensated by the simple coils used so far. Therefore another scheme with four skew quads arranged in two famili