Science.gov

Sample records for spatial error concealment

  1. New Hybrid Error Concealment for Digital Compressed Video

    NASA Astrophysics Data System (ADS)

    Hadar, Ofer; Huber, Merav; Huber, Revital; Greenberg, Shlomo

    2005-12-01

    Transmission of a compressed video signal over a lossy communication network exposes the information to losses and errors, which leads to significant visible errors in the reconstructed frames at the decoder side. In this paper we present a new hybrid error concealment algorithm for compressed video sequences, based on temporal and spatial concealment methods. We describe spatial and temporal techniques for the recovery of lost blocks. In particular, we develop postprocessing techniques for the reconstruction of missing or damaged macroblocks. A new decision support tree is developed to efficiently choose the best appropriate error concealment method, according to the spatial and temporal characteristics of the sequence. The proposed algorithm is compared to three error concealment methods: spatial, temporal, and a previous hybrid approach using different noise levels. The results are evaluated using four quality measures. We show that our error concealment scheme outperforms all the other three methods for all the tested video sequences.

  2. Video Error Concealment Using Fidelity Tracking

    NASA Astrophysics Data System (ADS)

    Yoneyama, Akio; Takishima, Yasuhiro; Nakajima, Yasuyuki; Hatori, Yoshinori

    We propose a method to prevent the degradation of decoded MPEG pictures caused by video transmission over error-prone networks. In this paper, we focus on the error concealment that is processed at the decoder without using any backchannels. Though there have been various approaches to this problem, they generally focus on minimizing the degradation measured frame by frame. Although this frame-level approach is effective in evaluating individual frame quality, in the sense of human perception, the most noticeable feature is the spatio-temporal discontinuity of the image feature in the decoded video image. We propose a novel error concealment algorithm comprising the combination of i) A spatio-temporal error recovery function with low processing cost, ii) A MB-based image fidelity tracking scheme, and iii) An adaptive post-filter using the fidelity information. It is demonstrated by experimental results that the proposed algorithm can significantly reduce the subjective degradation of corrupted MPEG video quality with about 30% of additional decoding processing power.

  3. JPEG2000-coded image error concealment exploiting convex sets projections.

    PubMed

    Atzori, Luigi; Ginesu, Giaime; Raccis, Alessio

    2005-04-01

    Transmission errors in JPEG2000 can be grouped into three main classes, depending on the affected area: LL, high frequencies at the lower decomposition levels, and high frequencies at the higher decomposition levels. The first type of errors are the most annoying but can be concealed exploiting the signal spatial correlation like in a number of techniques proposed in the past; the second are less annoying but more difficult to address; the latter are often imperceptible. In this paper, we address the problem of concealing the second class or errors when high bit-planes are damaged by proposing a new approach based on the theory of projections onto convex sets. Accordingly, the error effects are masked by iteratively applying two procedures: low-pass (LP) filtering in the spatial domain and restoration of the uncorrupted wavelet coefficients in the transform domain. It has been observed that a uniform LP filtering brought to some undesired side effects that negatively compensated the advantages. This problem has been overcome by applying an adaptive solution, which exploits an edge map to choose the optimal filter mask size. Simulation results demonstrated the efficiency of the proposed approach. PMID:15825483

  4. Content-based retransmission with error concealment for astronomical images

    NASA Astrophysics Data System (ADS)

    Thienphrapa, Paul; Boussalis, Helen; Liu, Charles; Rad, Khosrow; Dong, Jane

    2005-10-01

    The James Webb Space Telescope (JWST) is expected to produce a vast amount of images that are valuable for astronomical research and education. To support research activities related to JWST mission, NASA has provided funds to establish the Structures Pointing and Control Engineering (SPACE) Laboratory at the California State University, Los Angeles (CSULA). One of the research activities in SPACE lab is to design an effective and efficient transmission system to disseminate JWST images across the Internet. This paper presents a prioritized transmission method to provide the best quality of the transferred image based on the joint-optimization of content-based retransmission and error concealment. First, the astronomical image is compressed using a scalable wavelet-based approach, then packetized into independently decodable packets. To facilitate the joint-optimization of two mutually dependent error control methods, a novel content index is declared to represent the significance of the packet content as well as its importance in error concealment. Based on the defined content index, the optimal retransmission schedule is determined to maximize the quality of the received image under delay constraint with the given error concealment method. Experimental results demonstrate that the proposed approach is very effective to combat the packet loss during transmission to achieve a desirable quality of the received astronomical images.

  5. Video inpainting with short-term windows: application to object removal and error concealment.

    PubMed

    Ebdelli, Mounira; Le Meur, Olivier; Guillemot, Christine

    2015-10-01

    In this paper, we propose a new video inpainting method which applies to both static or free-moving camera videos. The method can be used for object removal, error concealment, and background reconstruction applications. To limit the computational time, a frame is inpainted by considering a small number of neighboring pictures which are grouped into a group of pictures (GoP). More specifically, to inpaint a frame, the method starts by aligning all the frames of the GoP. This is achieved by a region-based homography computation method which allows us to strengthen the spatial consistency of aligned frames. Then, from the stack of aligned frames, an energy function based on both spatial and temporal coherency terms is globally minimized. This energy function is efficient enough to provide high quality results even when the number of pictures in the GoP is rather small, e.g. 20 neighboring frames. This drastically reduces the algorithm complexity and makes the approach well suited for near real-time video editing applications as well as for loss concealment applications. Experiments with several challenging video sequences show that the proposed method provides visually pleasing results for object removal, error concealment, and background reconstruction context. PMID:26011884

  6. The successively temporal error concealment algorithm using error-adaptive block matching principle

    NASA Astrophysics Data System (ADS)

    Lee, Yu-Hsuan; Wu, Tsai-Hsing; Chen, Chao-Chyun

    2014-09-01

    Generally, the temporal error concealment (TEC) adopts the blocks around the corrupted block (CB) as the search pattern to find the best-match block in previous frame. Once the CB is recovered, it is referred to as the recovered block (RB). Although RB can be the search pattern to find the best-match block of another CB, RB is not the same as its original block (OB). The error between the RB and its OB limits the performance of TEC. The successively temporal error concealment (STEC) algorithm is proposed to alleviate this error. The STEC procedure consists of tier-1 and tier-2. The tier-1 divides a corrupted macroblock into four corrupted 8 × 8 blocks and generates a recovering order for them. The corrupted 8 × 8 block with the first place of recovering order is recovered in tier-1, and remaining 8 × 8 CBs are recovered in tier-2 along the recovering order. In tier-2, the error-adaptive block matching principle (EA-BMP) is proposed for the RB as the search pattern to recover remaining corrupted 8 × 8 blocks. The proposed STEC outperforms sophisticated TEC algorithms on average PSNR by 0.3 dB on the packet error rate of 20% at least.

  7. An edge-based temporal error concealment for MPEG-coded video

    NASA Astrophysics Data System (ADS)

    Huang, Yu-Len; Lien, Hsiu-Yi

    2005-07-01

    When transmitted over unreliable channels, the compressed video can suffer severe degradation. Some strategies were employed to make an acceptable quality of the decoded image sequence. Error concealment (EC) technique is one of effective approaches to diminish the quality degradation. A number of EC algorithms have been developed to combat the transmission errors for MPEG-coded video. These methods always work well to reconstruct the smooth or regular damaged macroblocks. However, for damaged macroblocks were irregular or high-detail, the reconstruction may follow noticeable blurring consequence or not match well with the surrounding macroblocks. This paper proposes an edgebased temporal EC model to conceal the errors. In the proposed method, both the spatial and the temporal contextual features in compressed video are measured by using an edge detector, i.e. Sobel operator. The edge information surrounding a damaged macroblock is utilized to estimate the lost motion vectors based on the boundary matching technique. Next, the estimated motion vectors are used to reconstruct the damaged macroblock by exploiting the information in reference frames. In comparison with traditional EC algorithms, the proposed method provides a significant improvement on both objective peak signal-to-noise ratio (PSNR) measurement and subjective visual quality of MPEG-coded video.

  8. Error concealment and early resynchronization techniques for MPEG-2 video streams damaged by transmission over ATM networks

    NASA Astrophysics Data System (ADS)

    Fernandez, Carlos L.; Basso, Andrea; Hubaux, Jean-Pierre

    1996-03-01

    In this paper we present some error concealment techniques for MPEG-2 video coded and multiplexed streams damaged by ATM cell losses. Decoder early resynchronization limits the effects of transmission errors by decoding some information that is normally discarded from the damaged MPEG-2 video bitstreams. A part of this information cannot be completely decoded due to its differential coding among macroblocks (DC levels, motion vectors). Three different techniques are presented for the case of DC level recovery in Intra pictures. Two of them are predictive techniques, one operating in the frequency domain and the other in the spatial domain. The third technique provides an exact reconstruction of DC values using special data coded into the user data area of the MPEG-2 video bitstream. For not resynchronized areas classical temporal and spatial concealment techniques are used. These techniques have been tested on a simulated environment which includes an implementation of MPEG-2 elementary video coding and decoding and MPEG-2 system standards. The ATM transmission part has been simulated by means of specialized simulation software. Results relative to the presented concealment techniques are included.

  9. EZBC video streaming with channel coding and error concealment

    NASA Astrophysics Data System (ADS)

    Bajic, Ivan V.; Woods, John W.

    2003-06-01

    In this text we present a system for streaming video content encoded using the motion-compensated Embedded Zero Block Coder (EZBC). The system incorporates unequal loss protection in the form of multiple description FEC (MD-FEC) coding, which provides adequate protection for the embedded video bitstream when the loss process is not very bursty. The adverse effects of burst losses are reduced using a novel motion-compensated error concealmet method.

  10. Pixel-level Matching Based Multi-hypothesis Error Concealment Modes for Wireless 3D H.264/MVC Communication

    NASA Astrophysics Data System (ADS)

    El-Shafai, Walid

    2015-09-01

    3D multi-view video (MVV) is multiple video streams shot by several cameras around a single scene simultaneously. Therefore it is an urgent task to achieve high 3D MVV compression to meet future bandwidth constraints while maintaining a high reception quality. 3D MVV coded bit-streams that are transmitted over wireless network can suffer from error propagation in the space, time and view domains. Error concealment (EC) algorithms have the advantage of improving the received 3D video quality without any modifications in the transmission rate or in the encoder hardware or software. To improve the quality of reconstructed 3D MVV, we propose an efficient adaptive EC algorithm with multi-hypothesis modes to conceal the erroneous Macro-Blocks (MBs) of intra-coded and inter-coded frames by exploiting the spatial, temporal and inter-view correlations between frames and views. Our proposed algorithm adapts to 3D MVV motion features and to the error locations. The lost MBs are optimally recovered by utilizing motion and disparity matching between frames and views on pixel-by-pixel matching basis. Our simulation results show that the proposed adaptive multi-hypothesis EC algorithm can significantly improve the objective and subjective 3D MVV quality.

  11. Spatial frequency domain error budget

    SciTech Connect

    Hauschildt, H; Krulewich, D

    1998-08-27

    The aim of this paper is to describe a methodology for designing and characterizing machines used to manufacture or inspect parts with spatial-frequency-based specifications. At Lawrence Livermore National Laboratory, one of our responsibilities is to design or select the appropriate machine tools to produce advanced optical and weapons systems. Recently, many of the component tolerances for these systems have been specified in terms of the spatial frequency content of residual errors on the surface. We typically use an error budget as a sensitivity analysis tool to ensure that the parts manufactured by a machine will meet the specified component tolerances. Error budgets provide the formalism whereby we account for all sources of uncertainty in a process, and sum them to arrive at a net prediction of how "precisely" a manufactured component can meet a target specification. Using the error budget, we are able to minimize risk during initial stages by ensuring that the machine will produce components that meet specifications before the machine is actually built or purchased. However, the current error budgeting procedure provides no formal mechanism for designing machines that can produce parts with spatial-frequency-based specifications. The output from the current error budgeting procedure is a single number estimating the net worst case or RMS error on the work piece. This procedure has limited ability to differentiate between low spatial frequency form errors versus high frequency surface finish errors. Therefore the current error budgeting procedure can lead us to reject a machine that is adequate or accept a machine that is inadequate. This paper will describe a new error budgeting methodology to aid in the design and characterization of machines used to manufacture or inspect parts with spatial-frequency-based specifications. The output from this new procedure is the continuous spatial frequency content of errors that result on a machined part. If the machine

  12. Using self-authentication and recovery images for error concealment in wireless environments

    NASA Astrophysics Data System (ADS)

    Lin, Ching-Yung; Sow, Daby; Chang, Shih-Fu

    2001-11-01

    Handling packet loss or delay in the mobile and/or Internet environment is usually a challenging problem for multimedia transmission. Using connection-oriented protocol such as TCP may introduce intolerable time delay in re-transmission. Using datagram-oriented protocols such as UDP may cause partial representation in case of packet loss. In this paper, we propose a new method of using our self-authentication-and-recovery images (SARI) to do the error detection and concealment in the UDP environment. The lost information in a SARI image can be approximately recovered based on the embedded watermark, which includes the content-based authentication information and recovery information. Images or video frames are watermarked in a priori such that no additional mechanism is needed in the networking or the encoding process. Because the recovery is not based on adjacent blocks, the proposed method can recover the corrupted area even though the information loss happen in large areas or high variant areas. Our experiments show the advantages of such technique in both transmission time saving and broad application potentials.

  13. Authenticating concealed private data while maintaining concealment

    DOEpatents

    Thomas, Edward V.; Draelos, Timothy J.

    2007-06-26

    A method of and system for authenticating concealed and statistically varying multi-dimensional data comprising: acquiring an initial measurement of an item, wherein the initial measurement is subject to measurement error; applying a transformation to the initial measurement to generate reference template data; acquiring a subsequent measurement of an item, wherein the subsequent measurement is subject to measurement error; applying the transformation to the subsequent measurement; and calculating a Euclidean distance metric between the transformed measurements; wherein the calculated Euclidean distance metric is identical to a Euclidean distance metric between the measurement prior to transformation.

  14. Unified error model based spatial error compensation for four types of CNC machining center: Part II-unified model based spatial error compensation

    NASA Astrophysics Data System (ADS)

    Fan, Kaiguo; Yang, Jianguo; Yang, Liyan

    2014-12-01

    In this paper, a spatial error compensation method was proposed for CNC machining center based on the unified error model. The spatial error distribution was analyzed in this research. The result shows that the spatial error is relative to each axis of a CNC machine tool. Moreover, the spatial error distribution is non-linear and there is no regularity. In order to improve the modeling accuracy and efficiency, an automatic error modeling application was designed based on the orthogonal polynomials. To realize the spatial error compensation, a multi-thread parallel processing mode based error compensation controller was designed. Using the spatial error compensation method, the machine tools' accuracy is greatly improved compared to that with no compensation.

  15. Deterministic error correction for nonlocal spatial-polarization hyperentanglement.

    PubMed

    Li, Tao; Wang, Guan-Yu; Deng, Fu-Guo; Long, Gui-Lu

    2016-01-01

    Hyperentanglement is an effective quantum source for quantum communication network due to its high capacity, low loss rate, and its unusual character in teleportation of quantum particle fully. Here we present a deterministic error-correction scheme for nonlocal spatial-polarization hyperentangled photon pairs over collective-noise channels. In our scheme, the spatial-polarization hyperentanglement is first encoded into a spatial-defined time-bin entanglement with identical polarization before it is transmitted over collective-noise channels, which leads to the error rejection of the spatial entanglement during the transmission. The polarization noise affecting the polarization entanglement can be corrected with a proper one-step decoding procedure. The two parties in quantum communication can, in principle, obtain a nonlocal maximally entangled spatial-polarization hyperentanglement in a deterministic way, which makes our protocol more convenient than others in long-distance quantum communication. PMID:26861681

  16. Deterministic error correction for nonlocal spatial-polarization hyperentanglement

    NASA Astrophysics Data System (ADS)

    Li, Tao; Wang, Guan-Yu; Deng, Fu-Guo; Long, Gui-Lu

    2016-02-01

    Hyperentanglement is an effective quantum source for quantum communication network due to its high capacity, low loss rate, and its unusual character in teleportation of quantum particle fully. Here we present a deterministic error-correction scheme for nonlocal spatial-polarization hyperentangled photon pairs over collective-noise channels. In our scheme, the spatial-polarization hyperentanglement is first encoded into a spatial-defined time-bin entanglement with identical polarization before it is transmitted over collective-noise channels, which leads to the error rejection of the spatial entanglement during the transmission. The polarization noise affecting the polarization entanglement can be corrected with a proper one-step decoding procedure. The two parties in quantum communication can, in principle, obtain a nonlocal maximally entangled spatial-polarization hyperentanglement in a deterministic way, which makes our protocol more convenient than others in long-distance quantum communication.

  17. Deterministic error correction for nonlocal spatial-polarization hyperentanglement

    PubMed Central

    Li, Tao; Wang, Guan-Yu; Deng, Fu-Guo; Long, Gui-Lu

    2016-01-01

    Hyperentanglement is an effective quantum source for quantum communication network due to its high capacity, low loss rate, and its unusual character in teleportation of quantum particle fully. Here we present a deterministic error-correction scheme for nonlocal spatial-polarization hyperentangled photon pairs over collective-noise channels. In our scheme, the spatial-polarization hyperentanglement is first encoded into a spatial-defined time-bin entanglement with identical polarization before it is transmitted over collective-noise channels, which leads to the error rejection of the spatial entanglement during the transmission. The polarization noise affecting the polarization entanglement can be corrected with a proper one-step decoding procedure. The two parties in quantum communication can, in principle, obtain a nonlocal maximally entangled spatial-polarization hyperentanglement in a deterministic way, which makes our protocol more convenient than others in long-distance quantum communication. PMID:26861681

  18. Measurement error caused by spatial misalignment in environmental epidemiology

    PubMed Central

    Gryparis, Alexandros; Paciorek, Christopher J.; Zeka, Ariana; Schwartz, Joel; Coull, Brent A.

    2009-01-01

    In many environmental epidemiology studies, the locations and/or times of exposure measurements and health assessments do not match. In such settings, health effects analyses often use the predictions from an exposure model as a covariate in a regression model. Such exposure predictions contain some measurement error as the predicted values do not equal the true exposures. We provide a framework for spatial measurement error modeling, showing that smoothing induces a Berkson-type measurement error with nondiagonal error structure. From this viewpoint, we review the existing approaches to estimation in a linear regression health model, including direct use of the spatial predictions and exposure simulation, and explore some modified approaches, including Bayesian models and out-of-sample regression calibration, motivated by measurement error principles. We then extend this work to the generalized linear model framework for health outcomes. Based on analytical considerations and simulation results, we compare the performance of all these approaches under several spatial models for exposure. Our comparisons underscore several important points. First, exposure simulation can perform very poorly under certain realistic scenarios. Second, the relative performance of the different methods depends on the nature of the underlying exposure surface. Third, traditional measurement error concepts can help to explain the relative practical performance of the different methods. We apply the methods to data on the association between levels of particulate matter and birth weight in the greater Boston area. PMID:18927119

  19. Client error concealment of RAID

    NASA Astrophysics Data System (ADS)

    Gu, Jian; Yu, Shengsheng; Zhou, Jingli; Zheng, Junhao

    2001-11-01

    A new technique to recover the information loss in a block-based image coding system is developed in this paper. Disk arrays organize multiple, independent disks into a large, high-performance logical disk. However, with more devices, reliability drops. A single disk failure in RAID level 5 will lead to the increase of the load of each surviving disk by 100% for data reconstruction. Each disk is loaded at less than 50% of its capacity in the fault-free state so that the surviving disks will not saturate when failure occurs. By image partitioning, decoder reconstructs DCT blocks in the sub-image and does not impose any significant load on the disk array. Our approach improves the quality of the compressed image by 2dB to 10dB and above and reduces the code overhead of the compressed image data by 2 percent to 10 percent and above for different images due to recovering main AC coefficients.

  20. Spatial reasoning in the treatment of systematic sensor errors

    SciTech Connect

    Beckerman, M.; Jones, J.P.; Mann, R.C.; Farkas, L.A.; Johnston, S.E.

    1988-01-01

    In processing ultrasonic and visual sensor data acquired by mobile robots systematic errors can occur. The sonar errors include distortions in size and surface orientation due to the beam resolution, and false echoes. The vision errors include, among others, ambiguities in discriminating depth discontinuities from intensity gradients generated by variations in surface brightness. In this paper we present a methodology for the removal of systematic errors using data from the sonar sensor domain to guide the processing of information in the vision domain, and vice versa. During the sonar data processing some errors are removed from 2D navigation maps through pattern analyses and consistent-labelling conditions, using spatial reasoning about the sonar beam and object characteristics. Others are removed using visual information. In the vision data processing vertical edge segments are extracted using a Canny-like algorithm, and are labelled. Object edge features are then constructed from the segments using statistical and spatial analyses. A least-squares method is used during the statistical analysis, and sonar range data are used in the spatial analysis. 7 refs., 10 figs.

  1. Concealment of sexual orientation.

    PubMed

    Sylva, David; Rieger, Gerulf; Linsenmeier, Joan A W; Bailey, J Michael

    2010-02-01

    Sex-atypical behaviors may be used to identify a person as homosexual. To shield themselves from prejudice, homosexual people may attempt to conceal these behaviors. It is not clear how effectively they can do so. In Study 1, we asked homosexual participants to conceal their sex-atypical behaviors while talking about the weather. Raters watched videos of the participants and judged the likelihood that each participant was homosexual. Homosexual participants were able to partially conceal signs of their orientation, but they remained distinguishable from heterosexual participants. In Study 2, we tested the ability to conceal signs of one's sexual orientation in a more demanding situation: a mock job interview. In this scenario, homosexual men were even less effective at concealing their orientation. Higher cognitive demands in this new situation may have interfered with their ability to conceal. PMID:19169803

  2. Spatial uncertainty analysis: Propagation of interpolation errors in spatially distributed models

    USGS Publications Warehouse

    Phillips, D.L.; Marks, D.G.

    1996-01-01

    In simulation modelling, it is desirable to quantify model uncertainties and provide not only point estimates for output variables but confidence intervals as well. Spatially distributed physical and ecological process models are becoming widely used, with runs being made over a grid of points that represent the landscape. This requires input values at each grid point, which often have to be interpolated from irregularly scattered measurement sites, e.g., weather stations. Interpolation introduces spatially varying errors which propagate through the model We extended established uncertainty analysis methods to a spatial domain for quantifying spatial patterns of input variable interpolation errors and how they propagate through a model to affect the uncertainty of the model output. We applied this to a model of potential evapotranspiration (PET) as a demonstration. We modelled PET for three time periods in 1990 as a function of temperature, humidity, and wind on a 10-km grid across the U.S. portion of the Columbia River Basin. Temperature, humidity, and wind speed were interpolated using kriging from 700- 1000 supporting data points. Kriging standard deviations (SD) were used to quantify the spatially varying interpolation uncertainties. For each of 5693 grid points, 100 Monte Carlo simulations were done, using the kriged values of temperature, humidity, and wind, plus random error terms determined by the kriging SDs and the correlations of interpolation errors among the three variables. For the spring season example, kriging SDs averaged 2.6??C for temperature, 8.7% for relative humidity, and 0.38 m s-1 for wind. The resultant PET estimates had coefficients of variation (CVs) ranging from 14% to 27% for the 10-km grid cells. Maps of PET means and CVs showed the spatial patterns of PET with a measure of its uncertainty due to interpolation of the input variables. This methodology should be applicable to a variety of spatially distributed models using interpolated

  3. [Prediction of spatial distribution of forest carbon storage in Heilongjiang Province using spatial error model].

    PubMed

    Liu, Chang; Li, Feng-Ri; Zhen, Zhen

    2014-10-01

    Abstract: Based on the data from Chinese National Forest Inventory (CNFI) and Key Ecological Benefit Forest Monitoring plots (5075 in total) in Heilongjiang Province in 2010 and concurrent meteorological data coming from 59 meteorological stations located in Heilongjiang, Jilin and Inner Mongolia, this paper established a spatial error model (SEM) by GeoDA using carbon storage as dependent variable and several independent variables, including diameter of living trees (DBH), number of trees per hectare (TPH), elevation (Elev), slope (Slope), and product of precipitation and temperature (Rain_Temp). Global Moran's I was computed for describing overall spatial autocorrelations of model results at different spatial scales. Local Moran's I was calculated at the optimal bandwidth (25 km) to present spatial distribution residuals. Intra-block spatial variances were computed to explain spatial heterogeneity of residuals. Finally, a spatial distribution map of carbon storage in Heilongjiang was visualized based on predictions. The results showed that the distribution of forest carbon storage in Heilongjiang had spatial effect and was significantly influenced by stand, topographic and meteorological factors, especially average DBH. SEM could solve the spatial autocorrelation and heterogeneity well. There were significant spatial differences in distribution of forest carbon storage. The carbon storage was mainly distributed in Zhangguangcai Mountain, Xiao Xing'an Mountain and Da Xing'an Mountain where dense, forests existed, rarely distributed in Songnen Plains, while Wanda Mountain had moderate-level carbon storage. PMID:25796882

  4. Augmented GNSS Differential Corrections Minimum Mean Square Error Estimation Sensitivity to Spatial Correlation Modeling Errors

    PubMed Central

    Kassabian, Nazelie; Presti, Letizia Lo; Rispoli, Francesco

    2014-01-01

    Railway signaling is a safety system that has evolved over the last couple of centuries towards autonomous functionality. Recently, great effort is being devoted in this field, towards the use and exploitation of Global Navigation Satellite System (GNSS) signals and GNSS augmentation systems in view of lower railway track equipments and maintenance costs, that is a priority to sustain the investments for modernizing the local and regional lines most of which lack automatic train protection systems and are still manually operated. The objective of this paper is to assess the sensitivity of the Linear Minimum Mean Square Error (LMMSE) algorithm to modeling errors in the spatial correlation function that characterizes true pseudorange Differential Corrections (DCs). This study is inspired by the railway application; however, it applies to all transportation systems, including the road sector, that need to be complemented by an augmentation system in order to deliver accurate and reliable positioning with integrity specifications. A vector of noisy pseudorange DC measurements are simulated, assuming a Gauss-Markov model with a decay rate parameter inversely proportional to the correlation distance that exists between two points of a certain environment. The LMMSE algorithm is applied on this vector to estimate the true DC, and the estimation error is compared to the noise added during simulation. The results show that for large enough correlation distance to Reference Stations (RSs) distance separation ratio values, the LMMSE brings considerable advantage in terms of estimation error accuracy and precision. Conversely, the LMMSE algorithm may deteriorate the quality of the DC measurements whenever the ratio falls below a certain threshold. PMID:24922454

  5. Augmented GNSS differential corrections minimum mean square error estimation sensitivity to spatial correlation modeling errors.

    PubMed

    Kassabian, Nazelie; Lo Presti, Letizia; Rispoli, Francesco

    2014-01-01

    Railway signaling is a safety system that has evolved over the last couple of centuries towards autonomous functionality. Recently, great effort is being devoted in this field, towards the use and exploitation of Global Navigation Satellite System (GNSS) signals and GNSS augmentation systems in view of lower railway track equipments and maintenance costs, that is a priority to sustain the investments for modernizing the local and regional lines most of which lack automatic train protection systems and are still manually operated. The objective of this paper is to assess the sensitivity of the Linear Minimum Mean Square Error (LMMSE) algorithm to modeling errors in the spatial correlation function that characterizes true pseudorange Differential Corrections (DCs). This study is inspired by the railway application; however, it applies to all transportation systems, including the road sector, that need to be complemented by an augmentation system in order to deliver accurate and reliable positioning with integrity specifications. A vector of noisy pseudorange DC measurements are simulated, assuming a Gauss-Markov model with a decay rate parameter inversely proportional to the correlation distance that exists between two points of a certain environment. The LMMSE algorithm is applied on this vector to estimate the true DC, and the estimation error is compared to the noise added during simulation. The results show that for large enough correlation distance to Reference Stations (RSs) distance separation ratio values, the LMMSE brings considerable advantage in terms of estimation error accuracy and precision. Conversely, the LMMSE algorithm may deteriorate the quality of the DC measurements whenever the ratio falls below a certain threshold. PMID:24922454

  6. Concealed wire tracing apparatus

    DOEpatents

    Kronberg, James W.

    1994-01-01

    An apparatus and method that combines a signal generator and a passive signal receiver to detect and record the path of partially or completely concealed electrical wiring without disturbing the concealing surface. The signal generator applies a series of electrical pulses to the selected wiring of interest. The applied pulses create a magnetic field about the wiring that can be detected by a coil contained within the signal receiver. An audible output connected to the receiver and driven by the coil reflects the receivers position with respect to the wiring. The receivers audible signal is strongest when the receiver is directly above the wiring and the long axis of the receivers coil is parallel to the wiring. A marking means is mounted on the receiver to mark the location of the wiring as the receiver is directed over the wiring's concealing surface. Numerous marks made on various locations of the concealing surface will trace the path of the wiring of interest.

  7. Pixelated mask spatial carrier phase shifting interferometry algorithms and associated errors

    SciTech Connect

    Kimbrough, Bradley T

    2006-07-01

    In both temporal and spatial carrier phase shifting interferometry, the primary source of phase calculation error results from an error in the relative phase shift between sample points. In spatial carrier phase shifting interferometry, this phase shifting error is caused directly by the wave front under test and is unavoidable. In order to minimize the phase shifting error, a pix elated spatial carrier phase shifting technique has been developed by 4D technologies. This new technique allows for the grouping of phase shifted pixels together around a single point in two dimensions,minimizing the phase shift change due to the spatial variation in the test wavefront. A formula for the phase calculation error in spatial carrier phase shifting interferometry is derived. The error associated with the use of linear N-point averaging algorithms is presented and compared with those of the pix elated spatial carrier technique.

  8. Evaluation and control of spatial frequency errors in reflective telescopes

    NASA Astrophysics Data System (ADS)

    Zhang, Xuejun; Zeng, Xuefeng; Hu, Haixiang; Zheng, Ligong

    2015-08-01

    In this paper, the influence on the image quality of manufacturing residual errors was studied. By analyzing the statistical distribution characteristics of the residual errors and their effects on PSF and MTF, we divided those errors into low, middle and high frequency domains using the unit "cycles per aperture". Two types of mid-frequency errors, algorithm intrinsic and tool path induced were analyzed. Control methods in current deterministic polishing process, such as MRF or IBF were presented.

  9. Large-scale spatial angle measurement and the pointing error analysis

    NASA Astrophysics Data System (ADS)

    Xiao, Wen-jian; Chen, Zhi-bin; Ma, Dong-xi; Zhang, Yong; Liu, Xian-hong; Qin, Meng-ze

    2016-05-01

    A large-scale spatial angle measurement method is proposed based on inertial reference. Common measurement reference is established in inertial space, and the spatial vector coordinates of each measured axis in inertial space are measured by using autocollimation tracking and inertial measurement technology. According to the spatial coordinates of each test vector axis, the measurement of large-scale spatial angle is easily realized. The pointing error of tracking device based on the two mirrors in the measurement system is studied, and the influence of different installation errors to the pointing error is analyzed. This research can lay a foundation for error allocation, calibration and compensation for the measurement system.

  10. ISAR for concealed objects imaging

    NASA Astrophysics Data System (ADS)

    Zhuravlev, A.; Razevig, V.; Vasiliev, I.; Ivashov, S.; Voronin, V.

    2015-03-01

    A new promising architecture of microwave personnel screening system is analyzed in this paper with numerical simulations. This architecture is based on the concept of inverse aperture synthesis applied to a naturally moving person. The extent of the synthetic aperture is formed by a stationary vertical linear antenna array and by a length of subject's trajectory as he moves in the vicinity of this antenna array. The coherent radar signal processing is achieved by a synchronous 3D video-sensor whose data are used to track the subject. The advantages of the proposed system architecture over currently existing systems are analyzed. Synthesized radar images are obtained by numerical simulations with a human torso model with concealed objects. Various aspects of the system architecture are considered, including: advantages of using sparse antenna arrays to decrease the number of antenna elements, the influence of positioning errors of body surface due to outer clothing. It was shown that detailed radar images of concealed objects can be obtained with a narrow-band signal due to the depth information available from the 3D video sensor. The considered ISAR architecture is considered perspective to be used on infrastructure objects owing to its superior qualities: highest throughput, small footprint, simple design of the radar sub-system, non-required co-operation of the subject.

  11. Characterization of Age Differences in Error Types in a Multitrial Spatial Learning Task

    ERIC Educational Resources Information Center

    Krueger, Lacy E.

    2013-01-01

    Although increased age is associated with greater errors in spatial memory tasks, it is unclear if there are age differences in error types. To investigate this, 334 participants (ages 22-88) completed a task in which they remembered object locations across multiple study-test trials. Far and close error types were categorized based on the spatial…

  12. Concealed wire tracing apparatus

    DOEpatents

    Kronberg, J.W.

    1994-05-31

    An apparatus and method that combines a signal generator and a passive signal receiver to detect and record the path of partially or completely concealed electrical wiring without disturbing the concealing surface is disclosed. The signal generator applies a series of electrical pulses to the selected wiring of interest. The applied pulses create a magnetic field about the wiring that can be detected by a coil contained within the signal receiver. An audible output connected to the receiver and driven by the coil reflects the receivers position with respect to the wiring. The receivers audible signal is strongest when the receiver is directly above the wiring and the long axis of the receivers coil is parallel to the wiring. A marking means is mounted on the receiver to mark the location of the wiring as the receiver is directed over the wiring's concealing surface. Numerous marks made on various locations of the concealing surface will trace the path of the wiring of interest. 4 figs.

  13. Concealing with Structured Light

    PubMed Central

    Sun, Jingbo; Zeng, Jinwei; Wang, Xi; Cartwright, Alexander N.; Litchinitser, Natalia M.

    2014-01-01

    While making objects less visible (or invisible) to a human eye or a radar has captured people's imagination for centuries, current attempts towards realization of this long-awaited functionality range from various stealth technologies to recently proposed cloaking devices. A majority of proposed approaches share a number of common deficiencies such as design complexity, polarization effects, bandwidth, losses and the physical size or shape requirement complicating their implementation especially at optical frequencies. Here we demonstrate an alternative way to conceal macroscopic objects by structuring light itself. In our approach, the incident light is transformed into an optical vortex with a dark core that can be used to conceal macroscopic objects. Once such a beam passed around the object it is transformed back into its initial Gaussian shape with minimum amplitude and phase distortions. Therefore, we propose to use that dark core of the vortex beam to conceal an object that is macroscopic yet small enough to fit the dark (negligibly low intensity) region of the beam. The proposed concealing approach is polarization independent, easy to fabricate, lossless, operates at wavelengths ranging from 560 to 700 nm, and can be used to hide macroscopic objects providing they are smaller than vortex core. PMID:24522638

  14. Concealing with Structured Light

    NASA Astrophysics Data System (ADS)

    Sun, Jingbo; Zeng, Jinwei; Wang, Xi; Cartwright, Alexander N.; Litchinitser, Natalia M.

    2014-02-01

    While making objects less visible (or invisible) to a human eye or a radar has captured people's imagination for centuries, current attempts towards realization of this long-awaited functionality range from various stealth technologies to recently proposed cloaking devices. A majority of proposed approaches share a number of common deficiencies such as design complexity, polarization effects, bandwidth, losses and the physical size or shape requirement complicating their implementation especially at optical frequencies. Here we demonstrate an alternative way to conceal macroscopic objects by structuring light itself. In our approach, the incident light is transformed into an optical vortex with a dark core that can be used to conceal macroscopic objects. Once such a beam passed around the object it is transformed back into its initial Gaussian shape with minimum amplitude and phase distortions. Therefore, we propose to use that dark core of the vortex beam to conceal an object that is macroscopic yet small enough to fit the dark (negligibly low intensity) region of the beam. The proposed concealing approach is polarization independent, easy to fabricate, lossless, operates at wavelengths ranging from 560 to 700 nm, and can be used to hide macroscopic objects providing they are smaller than vortex core.

  15. Canceling the momentum in a phase-shifting algorithm to eliminate spatially uniform errors.

    PubMed

    Hibino, Kenichi; Kim, Yangjin

    2016-08-10

    In phase-shifting interferometry, phase modulation nonlinearity causes both spatially uniform and nonuniform errors in the measured phase. Conventional linear-detuning error-compensating algorithms only eliminate the spatially variable error component. The uniform error is proportional to the inertial momentum of the data-sampling weight of a phase-shifting algorithm. This paper proposes a design approach to cancel the momentum by using characteristic polynomials in the Z-transform space and shows that an arbitrary M-frame algorithm can be modified to a new (M+2)-frame algorithm that acquires new symmetry to eliminate the uniform error. PMID:27534475

  16. Evaluation of MPEG4-SVC for QoE protection in the context of transmission errors

    NASA Astrophysics Data System (ADS)

    Pitrey, Yohann; Barkowsky, Marcus; Le Callet, Patrick; Pépion, Romuald

    2010-08-01

    Scalable Video Coding (SVC) provides a way to encapsulate several video layers with increasing quality and resolution in a single bitstream. Thus it is particularly adapted to address heterogeneous networks and a wide variety of decoding devices. In this paper, we evaluate the interest of SVC in a different context, which is error concealment after transmission on networks subject to packet loss. The encoded scalable video streams contain two layers with different spatial and temporal resolutions designed for mobile video communications with medium size and average to low bitrates. The main idea is to use the base layer to conceal errors in the higher layers if they are corrupted or lost. The base layer is first upscaled either spatially or temporally to reach the same resolution as the layer to conceal. Two error-concealment techniques using the base layer are then proposed for the MPEG-4 SVC standard, involving frame-level concealment and pixel-level concealment. These techniques are compared to the upscaled base layer as well as to a classical single-layer MPEG- 4 AVC/H.264 error-concealment technique. The comparison is carried out through a subjective experiment, in order to evaluate the Quality-of-Experience of the proposed techniques. We study several scenarios involving various bitrates and resolutions for the base layer of the SVC streams. The results show that SVC-based error concealment can provide significantly higher visual quality than single-layer-based techniques. Moreover, we demonstrate that the resolution and bitrate of the base layer have a strong impact on the perceived quality of the concealment.

  17. Effects and correction of magneto-optic spatial light modulator phase errors in an optical correlator

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Hine, Butler P.; Reid, Max B.

    1992-01-01

    The optical phase errors introduced into an optical correlator by the input and filter plane magnetooptic spatial light modulators have been studied. The magnitude of these phase errors is measured and characterized, their effects on the correlation results are evaluated, and a means of correction by a design modification of the binary phase-only optical-filter function is presented. The efficacy of the phase-correction technique is quantified and is found to restore the correlation characteristics to those obtained in the absence of errors, to a high degree. The phase errors of other correlator system elements are also discussed and treated in a similar fashion.

  18. Fourier decomposition of spatial localization errors reveals an idiotropic dominance of an internal model of gravity.

    PubMed

    De Sá Teixeira, Nuno Alexandre

    2014-12-01

    Given its conspicuous nature, gravity has been acknowledged by several research lines as a prime factor in structuring the spatial perception of one's environment. One such line of enquiry has focused on errors in spatial localization aimed at the vanishing location of moving objects - it has been systematically reported that humans mislocalize spatial positions forward, in the direction of motion (representational momentum) and downward in the direction of gravity (representational gravity). Moreover, spatial localization errors were found to evolve dynamically with time in a pattern congruent with an anticipated trajectory (representational trajectory). The present study attempts to ascertain the degree to which vestibular information plays a role in these phenomena. Human observers performed a spatial localization task while tilted to varying degrees and referring to the vanishing locations of targets moving along several directions. A Fourier decomposition of the obtained spatial localization errors revealed that although spatial errors were increased "downward" mainly along the body's longitudinal axis (idiotropic dominance), the degree of misalignment between the latter and physical gravity modulated the time course of the localization responses. This pattern is surmised to reflect increased uncertainty about the internal model when faced with conflicting cues regarding the perceived "downward" direction. PMID:25448714

  19. Instantaneous detection of spatial gradient errors in differential GNSS

    NASA Astrophysics Data System (ADS)

    Jing, Jing

    Global Navigation Satellite Systems (GNSS) have become a critical element of modern engineering and scientific applications. GPS is currently being used in the design of navigation systems for both civil and military aviation applications. Differential GPS carrier phase measurements between antennas provide a very precise measurement that is useful for these applications. In fact, ground infrastructure has already been implemented in the Ground Based Augmentation System (GBAS) to take advantage of these precise measurements for use in civil aviation. Furthermore, these antennas can also be used to detect and isolate certain signal-in-space (SIS) failures and anomalies that are hazardous to aviation applications, for example the ionospheric anomalies and ephemeris failures. This realization, in turn, has led to the development of numerous carrier-phase based monitors. One drawback of the majority of these monitors is that their performance within a given configuration is dependent on how antennas are paired to form double differences. In contrast, the null space monitor approach is developed to provide consistent detection performance regardless of how the antennas are paired which combines measurements from multiple, spatially separated ground antennas through a null space transformation. The instantaneous carrier phase monitor cannot detect all gradients due to the presence of integer ambiguities. These ambiguities cannot be resolved because the gradient magnitude is unknown a priori. Furthermore, it has been shown that the performance of such monitors is highly dependent on the reference antenna topology. The range of detectable gradients for all carrier phase monitors depends on two factors: the number of antennas and their configuration. Antenna configuration is often overlooked as a means to improve performance. and heuristic arguments typically prevail in the associated siting decisions. However. such heuristics do not provide the maximum detectable range of

  20. Quantitative analysis of spatial sampling error in the infant and adult electroencephalogram.

    PubMed

    Grieve, Philip G; Emerson, Ronald G; Isler, Joseph R; Stark, Raymond I

    2004-04-01

    The purpose of this report was to determine the required number of electrodes to record the infant and adult electroencephalogram (EEG) with a specified amount of spatial sampling error. We first developed mathematical theory that governs the spatial sampling of EEG data distributed on a spherical approximation to the scalp. We then used a concentric sphere model of current flow in the head to simulate realistic EEG data. Quantitative spatial sampling error was calculated for the simulated EEG, with additive measurement noise, for 64, 128, and 256 electrodes equally spaced over the surface of the sphere corresponding to the coverage of the human scalp by commercially available "geodesic" electrode arrays. We found the sampling error for the infant to be larger than that for the adult. For example, a sampling error of less than 10% for the adult was obtained with a 64-electrode array but a 256-electrode array was needed for the infant to achieve the same level of error. With the addition of measurement noise, with power 10 times less than that of the EEG, the sampling error increased to 25% for both the infant and adult, for these numbers of electrodes. These results show that accurate measurement of the spatial properties of the infant EEG requires more electrodes than for the adult. PMID:15050554

  1. The effects of weighting function errors on spatial filters for structural control. [sensors for vibration damping

    NASA Technical Reports Server (NTRS)

    Lindner, Douglas K.; Reichard, Karl M.

    1992-01-01

    Distributed-effect sensors, which respond to spatially distributed inputs over a significant gauge length, encompass piezoelectric laminate films, modal-domain optical fiber sensors, and holographic sensors; they can be fabricated with spatially varying sensitivity to a distributed measurand for spatial filtering. Such spatial filters are configurable to extract various structural parameters from distributed measurements that cannot be directly measured by sensors. A modeling is presently conducted for distributed-effect sensors' integration into state-space structural models, noting the effects of fabrication errors on sensor operation.

  2. Spatial heterogeneity of type I error for local cluster detection tests

    PubMed Central

    2014-01-01

    Background Just as power, type I error of cluster detection tests (CDTs) should be spatially assessed. Indeed, CDTs’ type I error and power have both a spatial component as CDTs both detect and locate clusters. In the case of type I error, the spatial distribution of wrongly detected clusters (WDCs) can be particularly affected by edge effect. This simulation study aims to describe the spatial distribution of WDCs and to confirm and quantify the presence of edge effect. Methods A simulation of 40 000 datasets has been performed under the null hypothesis of risk homogeneity. The simulation design used realistic parameters from survey data on birth defects, and in particular, two baseline risks. The simulated datasets were analyzed using the Kulldorff’s spatial scan as a commonly used test whose behavior is otherwise well known. To describe the spatial distribution of type I error, we defined the participation rate for each spatial unit of the region. We used this indicator in a new statistical test proposed to confirm, as well as quantify, the edge effect. Results The predefined type I error of 5% was respected for both baseline risks. Results showed strong edge effect in participation rates, with a descending gradient from center to edge, and WDCs more often centrally situated. Conclusions In routine analysis of real data, clusters on the edge of the region should be carefully considered as they rarely occur when there is no cluster. Further work is needed to combine results from power studies with this work in order to optimize CDTs performance. PMID:24885343

  3. Spatial Resolution, Grayscale, and Error Diffusion Trade-offs: Impact on Display System Design

    NASA Technical Reports Server (NTRS)

    Gille, Jennifer L. (Principal Investigator)

    1996-01-01

    We examine technology trade-offs related to grayscale resolution, spatial resolution, and error diffusion for tessellated display systems. We present new empirical results from our psychophysical study of these trade-offs and compare them to the predictions of a model of human vision.

  4. Self-Concealment and Suicidal Behaviors

    ERIC Educational Resources Information Center

    Friedlander, Adam; Nazem, Sarra; Fiske, Amy; Nadorff, Michael R.; Smith, Merideth D.

    2012-01-01

    Understanding self-concealment, the tendency to actively conceal distressing personal information from others, may be important in developing effective ways to help individuals with suicidal ideation. No published study has yet assessed the relation between self-concealment and suicidal behaviors. Additionally, most self-concealment research has…

  5. Detection of a concealed object

    DOEpatents

    Keller, Paul E.; Hall, Thomas E.; McMakin, Douglas L.

    2008-04-29

    Disclosed are systems, methods, devices, and apparatus to determine if a clothed individual is carrying a suspicious, concealed object. This determination includes establishing data corresponding to an image of the individual through interrogation with electromagnetic radiation in the 200 MHz to 1 THz range. In one form, image data corresponding to intensity of reflected radiation and differential depth of the reflecting surface is received and processed to detect the suspicious, concealed object.

  6. Detection of a concealed object

    DOEpatents

    Keller, Paul E [Richland, WA; Hall, Thomas E [Kennewick, WA; McMakin, Douglas L [Richland, WA

    2010-11-16

    Disclosed are systems, methods, devices, and apparatus to determine if a clothed individual is carrying a suspicious, concealed object. This determination includes establishing data corresponding to an image of the individual through interrogation with electromagnetic radiation in the 200 MHz to 1 THz range. In one form, image data corresponding to intensity of reflected radiation and differential depth of the reflecting surface is received and processed to detect the suspicious, concealed object.

  7. Spatial effects, sampling errors, and task specialization in the honey bee.

    PubMed

    Johnson, B R

    2010-05-01

    Task allocation patterns should depend on the spatial distribution of work within the nest, variation in task demand, and the movement patterns of workers, however, relatively little research has focused on these topics. This study uses a spatially explicit agent based model to determine whether such factors alone can generate biases in task performance at the individual level in the honey bees, Apis mellifera. Specialization (bias in task performance) is shown to result from strong sampling error due to localized task demand, relatively slow moving workers relative to nest size, and strong spatial variation in task demand. To date, specialization has been primarily interpreted with the response threshold concept, which is focused on intrinsic (typically genotypic) differences between workers. Response threshold variation and sampling error due to spatial effects are not mutually exclusive, however, and this study suggests that both contribute to patterns of task bias at the individual level. While spatial effects are strong enough to explain some documented cases of specialization; they are relatively short term and not explanatory for long term cases of specialization. In general, this study suggests that the spatial layout of tasks and fluctuations in their demand must be explicitly controlled for in studies focused on identifying genotypic specialists. PMID:20351761

  8. Refining measurements of lateral channel movement from image time series by quantifying spatial variations in registration error

    NASA Astrophysics Data System (ADS)

    Lea, Devin M.; Legleiter, Carl J.

    2016-04-01

    Remotely sensed data provides information on river morphology useful for examining channel change at yearly-to-decadal time scales. Although previous studies have emphasized the need to distinguish true geomorphic change from errors associated with image registration, standard metrics for assessing and summarizing these errors, such as the root-mean-square error (RMSE) and 90th percentile of the distribution of ground control point (GCP) error, fail to incorporate the spatial structure of this uncertainty. In this study, we introduce a framework for evaluating whether observations of lateral channel migration along a meandering channel are statistically significant, given the spatial distribution of registration error. An iterative leave-one-out cross-validation approach was used to produce local error metrics for an image time series from Savery Creek, Wyoming, USA, and to evaluate various transformation equations, interpolation methods, and GCP placement strategies. Interpolated error surfaces then were used to create error ellipses representing spatially variable buffers of detectable change. Our results show that, for all five sequential image pairs we examined, spatially distributed estimates of registration error enabled detection of a greater number of statistically significant lateral migration vectors than the spatially uniform RMSE or 90th percentile of GCP error. Conversely, spatially distributed error metrics prevented changes from being mistaken as real in areas of greater registration error. Our results also support the findings of previous studies: second-order polynomial functions on average yield the lowest RMSE, and errors are reduced by placing GCPs on the floodplain rather than on hillslopes. This study highlights the importance of characterizing the spatial distribution of image registration errors in the analysis of channel change.

  9. A parametric multiclass Bayes error estimator for the multispectral scanner spatial model performance evaluation

    NASA Technical Reports Server (NTRS)

    Mobasseri, B. G.; Mcgillem, C. D.; Anuta, P. E. (Principal Investigator)

    1978-01-01

    The author has identified the following significant results. The probability of correct classification of various populations in data was defined as the primary performance index. The multispectral data being of multiclass nature as well, required a Bayes error estimation procedure that was dependent on a set of class statistics alone. The classification error was expressed in terms of an N dimensional integral, where N was the dimensionality of the feature space. The multispectral scanner spatial model was represented by a linear shift, invariant multiple, port system where the N spectral bands comprised the input processes. The scanner characteristic function, the relationship governing the transformation of the input spatial, and hence, spectral correlation matrices through the systems, was developed.

  10. Minimizing high spatial frequency residual error in active space telescope mirrors

    NASA Astrophysics Data System (ADS)

    Gray, Thomas L.; Smith, Matthew W.; Cohan, Lucy E.; Miller, David W.

    2009-08-01

    The trend in future space telescopes is towards larger apertures, which provide increased sensitivity and improved angular resolution. Lightweight, segmented, rib-stiffened, actively controlled primary mirrors are an enabling technology, permitting large aperture telescopes to meet the mass and volume restrictions imposed by launch vehicles. Such mirrors, however, are limited in the extent to which their discrete surface-parallel electrostrictive actuators can command global prescription changes. Inevitably some amount of high spatial frequency residual error is added to the wavefront due to the discrete nature of the actuators. A parameterized finite element mirror model is used to simulate this phenomenon and determine designs that mitigate high spatial frequency residual errors in the mirror surface figure. Two predominant residual components are considered: dimpling induced by embedded actuators and print-through induced by facesheet polishing. A gradient descent algorithm is combined with the parameterized mirror model to allow rapid trade space navigation and optimization of the mirror design, yielding advanced design heuristics formulated in terms of minimum machinable rib thickness. These relationships produce mirrors that satisfy manufacturing constraints and minimize uncorrectable high spatial frequency error.

  11. Sinusoidal Siemens star spatial frequency response measurement errors due to misidentified target centers

    SciTech Connect

    Birch, Gabriel Carisle; Griffin, John Clark

    2015-07-23

    Numerous methods are available to measure the spatial frequency response (SFR) of an optical system. A recent change to the ISO 12233 photography resolution standard includes a sinusoidal Siemens star test target. We take the sinusoidal Siemens star proposed by the ISO 12233 standard, measure system SFR, and perform an analysis of errors induced by incorrectly identifying the center of a test target. We show a closed-form solution for the radial profile intensity measurement given an incorrectly determined center and describe how this error reduces the measured SFR of the system. As a result, using the closed-form solution, we propose a two-step process by which test target centers are corrected and the measured SFR is restored to the nominal, correctly centered values.

  12. Sinusoidal Siemens star spatial frequency response measurement errors due to misidentified target centers

    DOE PAGESBeta

    Birch, Gabriel Carisle; Griffin, John Clark

    2015-07-23

    Numerous methods are available to measure the spatial frequency response (SFR) of an optical system. A recent change to the ISO 12233 photography resolution standard includes a sinusoidal Siemens star test target. We take the sinusoidal Siemens star proposed by the ISO 12233 standard, measure system SFR, and perform an analysis of errors induced by incorrectly identifying the center of a test target. We show a closed-form solution for the radial profile intensity measurement given an incorrectly determined center and describe how this error reduces the measured SFR of the system. As a result, using the closed-form solution, we proposemore » a two-step process by which test target centers are corrected and the measured SFR is restored to the nominal, correctly centered values.« less

  13. Quantifying spatial distribution of snow depth errors from LiDAR using Random Forests

    NASA Astrophysics Data System (ADS)

    Tinkham, W.; Smith, A. M.; Marshall, H.; Link, T. E.; Falkowski, M. J.; Winstral, A. H.

    2013-12-01

    There is increasing need to characterize the distribution of snow in complex terrain using remote sensing approaches, especially in isolated mountainous regions that are often water-limited, the principal source of terrestrial freshwater, and sensitive to climatic shifts and variations. We apply intensive topographic surveys, multi-temporal LiDAR, and Random Forest modeling to quantify snow volume and characterize associated errors across seven land cover types in a semi-arid mountainous catchment at a 1 and 4 m spatial resolution. The LiDAR-based estimates of both snow-off surface topology and snow depths were validated against ground-based measurements across the catchment. Comparison of LiDAR-derived snow depths to manual snow depth surveys revealed that LiDAR based estimates were more accurate in areas of low lying vegetation such as shrubs (RMSE = 0.14 m) as compared to areas consisting of tree cover (RMSE = 0.20-0.35 m). The highest errors were found along the edge of conifer forests (RMSE = 0.35 m), however a second conifer transect outside the catchment had much lower errors (RMSE = 0.21 m). This difference is attributed to the wind exposure of the first site that led to highly variable snow depths at short spatial distances. The Random Forest modeled errors deviated from the field measured errors with a RMSE of 0.09-0.34 m across the different cover types. Results show that snow drifts, which are important for maintaining spring and summer stream flows and establishing and sustaining water-limited plant species, contained 30 × 5-6% of the snow volume while only occupying 10% of the catchment area similar to findings by prior physically-based modeling approaches. This study demonstrates the potential utility of combining multi-temporal LiDAR with Random Forest modeling to quantify the distribution of snow depth with a reasonable degree of accuracy. Future work could explore the utility of Terrestrial LiDAR Scanners to produce validation of snow-on surface

  14. Standoff detection of concealed handguns

    NASA Astrophysics Data System (ADS)

    Rezgui, Nacer; Andrews, David; Bowring, Nicholas; Harmer, Stuart; Southgate, Matthew

    2008-04-01

    An active technique for the standoff detection and identification of concealed conducting items such as handguns and knives is presented. This technique entails illuminating an object with wide range stepped millimetre wave radiation and inducing a local electromagnetic field comprised of a superposition of modes. The coupling to these modes from the illuminating and scattered fields is, in general, frequency dependent and this forms the basis for the detection and identification of conducting items. The object needs to be fully illuminated if a full spectrum of modes and therefore a full frequency response are to be excited and collected. The scattered EM power is measured at "stand off" distance of several metres as the illuminating field is frequency swept and patterns in frequency response characteristic to the target item being sought are looked for. This system relies on contributions from the aspect independent late time responses employed by Baum1 together with aspect independent information derived specifically from gun barrels and polarisation from scattering effects. This technique is suitable for a deployable gun and concealed weapons detection system and does not rely on imaging techniques for determining the presence of a gun. Experimental sets of responses from typical metal or partially conducting objects such as keys, mobile phones and concealed handguns are presented at a range of frequencies.

  15. Handheld ultrasonic concealed weapon detector

    NASA Astrophysics Data System (ADS)

    Wild, Norbert C.; Doft, Frank; Breuner, Dennis; Felber, Franklin S.

    2001-02-01

    A handheld, battery-operated prototype of a concealed weapon detector has been built and tested. Designed to detect both metallic and non-metallic weapons, the sensor utilizes focused ultrasound (40 kHz frequency) to remotely detect concealed objects from beyond arm's length out to a range of about 12 feet (4 meters). The detector can be used in prison settings, by officers in the field to allow for stand-off frisking of suspects, and to supplement security at courthouse entrances and other monitored portals. The detector emits an audible alarm (with provision for an earphone jack) as well as a visible light-bar indicator when an object is detected. A high intensity aiming light, with momentary switch, allows the user to accurately determine the location of the concealed object. Current efforts are aimed at increasing the probability of detection, reducing the false-alarm rate, and extending the range of detectability out to 20 feet. Plans for accomplishing these tasks will be presented together with data showing the effective range and probability of detection for the present system.

  16. Method for imaging a concealed object

    DOEpatents

    Davidson, James R [Idaho Falls, ID; Partin, Judy K [Idaho Falls, ID; Sawyers, Robert J [Idaho Falls, ID

    2007-07-03

    A method for imaging a concealed object is described and which includes a step of providing a heat radiating body, and wherein an object to be detected is concealed on the heat radiating body; imaging the heat radiating body to provide a visibly discernible infrared image of the heat radiating body; and determining if the visibly discernible infrared image of the heat radiating body is masked by the presence of the concealed object.

  17. Error and correction for MODIS-AM's spatial response on the NDVI and EVI science products

    NASA Astrophysics Data System (ADS)

    Rojas, Francisco; Schowengerdt, Robert A.; Biggar, Stuart F.

    2002-09-01

    The accuracy of the Moderate Resolution Imaging Spectroradiometer (MODIS) end data products, such as the Vegetation Indices (VIs), are affected by MODIS's Spatial Response (SR). An error analysis is presented for the VI (MOD-13) product using Point Spread Response (PSR) data and improvement using a correction filter is demonstrated. The PSR data is a set of laboratory measurements that include electronic/optical cross-talk (pre-August 1998). The ensquared energy concept is applied to the PSR data to determine upper limits for the Far Field Response (FFR)(unwanted noise) that may be present in the MODIS data. The error is presented using spectral variation, Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) which demonstrate that the science products are dependent on the sensor's SR. A correction filter for the MODIS SR shows a qualitative and quantitative improvement using a scene Railroad Valley scene, June 14th 2001 in which Landsat 7 ETM+ is used as the reference.

  18. Unified error model based spatial error compensation for four types of CNC machining center: Part I-Singular function based unified error model

    NASA Astrophysics Data System (ADS)

    Fan, Kaiguo; Yang, Jianguo; Yang, Liyan

    2015-08-01

    To unify the error model for four types of CNC machining center, the comprehensive error model of each type of CNC machining center was established using the homogenous transformation matrix (HTM). The internal rules between the HTMs and the kinematic chains were analyzed in this research. The analysis results show that the HTM elements associated with the motion axes which are at the rear of the reference coordinate system are positive value. On the contrary, the HTM elements associated with the motion axes which are at the front of the reference coordinate system are negative value. To express these internal rules, the singular function was introduced to the HTMs. And a unified error model for four types of CNC machining center was established based on the HTM and the singular function. The unified error model includes 18 error elements which are the main factors affecting the machining accuracy of CNC machine tools. The practical results show that the unified error model is not only suitable for vertical machining center but also suitable for horizontal machining center.

  19. Effect of mid- and high-spatial frequencies on optical performance. [surface error effects on reflecting telescopes

    NASA Technical Reports Server (NTRS)

    Noll, R. J.

    1979-01-01

    In many of today's telescopes the effects of surface errors on image quality and scattered light are very important. The influence of optical fabrication surface errors on the performance of an optical system is discussed. The methods developed by Hopkins (1957) for aberration tolerancing and Barakat (1972) for random wavefront errors are extended to the examination of mid- and high-spatial frequency surface errors. The discussion covers a review of the basic concepts of image quality, an examination of manufacturing errors as a function of image quality performance, a demonstration of mirror scattering effects in relation to surface errors, and some comments on the nature of the correlation functions. Illustrative examples are included.

  20. Spatial and temporal patterns of error in land cover change analyses: Identifying and propagating uncertainty for ecological monitoring and modeling

    NASA Astrophysics Data System (ADS)

    Burnicki, Amy Colette

    Improving our understanding of the uncertainty associated with a map of land-cover change is needed given the importance placed on modeling our changing landscape. My dissertation research addressed the challenges of estimating the accuracy of a map of change by improving our understanding of the spatio-temporal structure of error in multi-date classified imagery, investigating the relative strength and importance of a temporal dependence between classification errors in multi-date imagery, and exploring the interaction of classification errors within a simulated model of land-cover change. First, I quantified the spatial and temporal patterns of error in multi-date classified imagery acquired for Pittsfield Township, Michigan. Specifically, I examined the propagation of error in a post-classification change analysis. The spatial patterns of misclassification for each classified map, the temporal correlation between the errors in each classified map, and secondary variables that may have affected the pattern of error associated with the map of change were analyzed by addressing a series of research hypothesis. The results of all analyses provided a thorough description and understanding of the spatio-temporal error structure for this test township. Second, I developed a model of error propagation in land-cover change that simulated user-defined spatial and temporal patterns of error within a time-series of classified maps to assess the impact of the specified error patterns on the accuracy of the resulting map of change. Two models were developed. The first established the overall modeling framework using land-cover maps composed of two land-cover classes. The second extended the initial model by using three land-cover class maps to investigate model performance under increased landscape complexity. The results of the simulated model demonstrated that the presence of temporal interaction between the errors of individual classified maps affected the resulting

  1. Extracting concealed information from groups.

    PubMed

    Meijer, Ewout H; Smulders, Fren T Y; Merckelbach, Harald L G J

    2010-11-01

    Lie detection procedures are typically aimed at determining guilt or innocence of a single suspect. Serious security threats, however, often involve groups, such as terrorist networks or criminal organizations. In this report, we describe a variant of the skin conductance-based Concealed Information Test (CIT) that allows for the extraction of critical information from such groups. Twelve participants were given information about an upcoming (mock) terrorist attack, with specific instructions not to reveal this information to anyone. Next, each subject was subjected to a CIT, with questions pertaining to the details of the attack. Results showed that for every question, the average skin conductance response to the correct answer option differed significantly (p < 0.05) from those to all other options. These results show that the information about the upcoming attack could be extracted from the group of terror suspects as a whole. PMID:20533975

  2. Control of mid-spatial frequency errors considering the pad groove feature in smoothing polishing process.

    PubMed

    Nie, Xuqing; Li, Shengyi; Hu, Hao; Li, Qi

    2014-10-01

    Mid-spatial frequency error (MSFR) should be strictly controlled in modern optical systems. As an effective approach to suppress MSFR, the smoothing polishing (SP) process is not easy to handle because it can be affected by many factors. This paper mainly focuses on the influence of the pad groove, which has not been researched yet. The SP process is introduced, and the important role of the pad groove is explained in detail. The relationship between the contact pressure distribution and the groove feature including groove section type, groove width, and groove depth is established, and the optimized result is achieved with the finite element method. The different kinds of groove patterns are compared utilizing the numerical superposition method established scrupulously. The optimal groove is applied in the verification experiment conducted on a self-developed SP machine. The root mean square value of the MSFR after the SP process is diminished from 2.38 to 0.68 nm, which reveals that the selected pad can smooth out the MSFR to a great extent with proper SP parameters, while the newly generated MSFR due to the groove can be suppressed to a very low magnitude. PMID:25322215

  3. Effects of Head Rotation on Space- and Word-Based Reading Errors in Spatial Neglect

    ERIC Educational Resources Information Center

    Reinhart, Stefan; Keller, Ingo; Kerkhoff, Georg

    2010-01-01

    Patients with right hemisphere lesions often omit or misread words on the left side of a text or the beginning letters of single words which is termed neglect dyslexia (ND). Two types of reading errors are typically observed in ND: omissions and word-based reading errors. The prior are considered as space-based omission errors on the…

  4. Terahertz interferometric imaging of a concealed object

    NASA Astrophysics Data System (ADS)

    Sinyukov, Alexander M.; Bandyopadhyay, Aparajita; Sengupta, Amartya; Barat, Robert B.; Gary, Dale E.; Michalopoulou, Zoi-Heleni; Zimdars, David; Federici, John F.

    2006-10-01

    Experimental results of two-dimensional homodyne terahertz interferometric imaging are presented. The performance of an N element detector array is imitated by only one detector placed at N positions. Continuous waves at 0.25-0.3 THz are used to detect concealed objects: a metal object and an RDX sample. The terahertz interferometric imaging method can be used in defense and security applications to detect concealed weapons, explosives as well as chemical and biological agents.

  5. Detecting changes in retinal function: Analysis with Non-Stationary Weibull Error Regression and Spatial enhancement (ANSWERS).

    PubMed

    Zhu, Haogang; Russell, Richard A; Saunders, Luke J; Ceccon, Stefano; Garway-Heath, David F; Crabb, David P

    2014-01-01

    Visual fields measured with standard automated perimetry are a benchmark test for determining retinal function in ocular pathologies such as glaucoma. Their monitoring over time is crucial in detecting change in disease course and, therefore, in prompting clinical intervention and defining endpoints in clinical trials of new therapies. However, conventional change detection methods do not take into account non-stationary measurement variability or spatial correlation present in these measures. An inferential statistical model, denoted 'Analysis with Non-Stationary Weibull Error Regression and Spatial enhancement' (ANSWERS), was proposed. In contrast to commonly used ordinary linear regression models, which assume normally distributed errors, ANSWERS incorporates non-stationary variability modelled as a mixture of Weibull distributions. Spatial correlation of measurements was also included into the model using a Bayesian framework. It was evaluated using a large dataset of visual field measurements acquired from electronic health records, and was compared with other widely used methods for detecting deterioration in retinal function. ANSWERS was able to detect deterioration significantly earlier than conventional methods, at matched false positive rates. Statistical sensitivity in detecting deterioration was also significantly better, especially in short time series. Furthermore, the spatial correlation utilised in ANSWERS was shown to improve the ability to detect deterioration, compared to equivalent models without spatial correlation, especially in short follow-up series. ANSWERS is a new efficient method for detecting changes in retinal function. It allows for better detection of change, more efficient endpoints and can potentially shorten the time in clinical trials for new therapies. PMID:24465636

  6. Exact error rate analysis of free-space optical communications with spatial diversity over Gamma-Gamma atmospheric turbulence

    NASA Astrophysics Data System (ADS)

    Ma, Jing; Li, Kangning; Tan, Liying; Yu, Siyuan; Cao, Yubin

    2016-02-01

    The error rate performances and outage probabilities of free-space optical (FSO) communications with spatial diversity are studied for Gamma-Gamma turbulent environments. Equal gain combining (EGC) and selection combining (SC) diversity are considered as practical schemes to mitigate turbulence. The exact bit-error rate (BER) expression and outage probability are derived for direct detection EGC multiple aperture receiver system. BER performances and outage probabilities are analyzed and compared for different number of sub-apertures each having aperture area A with EGC and SC techniques. BER performances and outage probabilities of a single monolithic aperture and multiple aperture receiver system with the same total aperture area are compared under thermal-noise-limited and background-noise-limited conditions. It is shown that multiple aperture receiver system can greatly improve the system communication performances. And these analytical tools are useful in providing highly accurate error rate estimation for FSO communication systems.

  7. Spatial accounting for errors in LiDAR-derived products: Snow volume and snow water equivalent estimation

    NASA Astrophysics Data System (ADS)

    Tinkham, W. T.; Hoffman, C. M.; Falkowski, M. J.; Smith, A. M.; Link, T. E.; Marshall, H.

    2011-12-01

    Light Detection and Ranging (LiDAR) has become one of the most effective and reliable means of characterizing surface topography and vegetation structure. Most LiDAR-derived estimates such as vegetation height, snow depth, and floodplain boundaries rely on the accurate creation of digital terrain models (DTM). As a result of the importance of an accurate DTM in using LiDAR data to estimate snow depth, it is necessary to understand the variables that influence the DTM accuracy in order to assess snow depth error. A series of 4 x 4 m plots that were surveyed at 0.5 m spacing in a semi-arid catchment were used for training the Random Forests algorithm along with a series of 35 variables in order to spatially predict vertical error within a LiDAR derived DTM. The final model was utilized to predict the combined error resulting from snow volume and snow water equivalent estimates derived from a snow-free LiDAR DTM and a snow-on LiDAR acquisition of the same site. The methodology allows for a statistical quantification of the spatially-distributed error patterns that are incorporated into the estimation of snow volume and snow water equivalents from LiDAR.

  8. Spatial and Temporal Characteristics of Error-Related Activity in the Human Brain

    PubMed Central

    Miezin, Francis M.; Nelson, Steven M.; Dubis, Joseph W.; Dosenbach, Nico U.F.; Schlaggar, Bradley L.; Petersen, Steven E.

    2015-01-01

    A number of studies have focused on the role of specific brain regions, such as the dorsal anterior cingulate cortex during trials on which participants make errors, whereas others have implicated a host of more widely distributed regions in the human brain. Previous work has proposed that there are multiple cognitive control networks, raising the question of whether error-related activity can be found in each of these networks. Thus, to examine error-related activity broadly, we conducted a meta-analysis consisting of 12 tasks that included both error and correct trials. These tasks varied by stimulus input (visual, auditory), response output (button press, speech), stimulus category (words, pictures), and task type (e.g., recognition memory, mental rotation). We identified 41 brain regions that showed a differential fMRI BOLD response to error and correct trials across a majority of tasks. These regions displayed three unique response profiles: (1) fast, (2) prolonged, and (3) a delayed response to errors, as well as a more canonical response to correct trials. These regions were found mostly in several control networks, each network predominantly displaying one response profile. The one exception to this “one network, one response profile” observation is the frontoparietal network, which showed prolonged response profiles (all in the right hemisphere), and fast profiles (all but one in the left hemisphere). We suggest that, in the place of a single localized error mechanism, these findings point to a large-scale set of error-related regions across multiple systems that likely subserve different functions. PMID:25568119

  9. Quantification of errors in large-eddy simulations of a spatially evolving mixing layer using polynomial chaos

    SciTech Connect

    Meldi, M.; Sagaut, P.; Salvetti, M. V.

    2012-03-15

    A stochastic approach based on generalized polynomial chaos (gPC) is used to quantify the error in large-eddy simulation (LES) of a spatially evolving mixing layer flow and its sensitivity to different simulation parameters, viz., the grid stretching in the streamwise and lateral directions and the subgrid-scale (SGS) Smagorinsky model constant (C{sub S}). The error is evaluated with respect to the results of a highly resolved LES and for different quantities of interest, namely, the mean streamwise velocity, the momentum thickness, and the shear stress. A typical feature of the considered spatially evolving flow is the progressive transition from a laminar regime, highly dependent on the inlet conditions, to a fully developed turbulent one. Therefore, the computational domain is divided in two different zones (inlet dependent and fully turbulent) and the gPC error analysis is carried out for these two zones separately. An optimization of the parameters is also carried out for both these zones. For all the considered quantities, the results point out that the error is mainly governed by the value of the C{sub S} constant. At the end of the inlet-dependent zone, a strong coupling between the normal stretching ratio and the C{sub S} value is observed. The error sensitivity to the parameter values is significantly larger in the inlet-dependent upstream region; however, low-error values can be obtained in this region for all the considered physical quantities by an ad hoc tuning of the parameters. Conversely, in the turbulent regime the error is globally lower and less sensitive to the parameter variations, but it is more difficult to find a set of parameter values leading to optimal results for all the analyzed physical quantities. A similar analysis is also carried out for the dynamic Smagorinsky model, by varying the grid stretching ratios. Comparing the databases generated with the different subgrid-scale models, it is possible to observe that the error cost

  10. Concealed target detection using augmented reality with SIRE radar

    NASA Astrophysics Data System (ADS)

    Saponaro, Philip; Kambhamettu, Chandra; Ranney, Kenneth; Sullivan, Anders

    2013-05-01

    The Synchronous Impulse Reconstruction (SIRE) forward-looking radar, developed by the U.S. Army Research Laboratory (ARL), can detect concealed targets using ultra-wideband synthetic aperture technology. The SIRE radar has been mounted on a Ford Expedition and combined with other sensors, including a pan/tilt/zoom camera, to test its capabilities of concealed target detection in a realistic environment. Augmented Reality (AR) can be used to combine the SIRE radar image with the live camera stream into one view, which provides the user with information that is quicker to assess and easier to understand than each separated. In this paper we present an AR system which utilizes a global positioning system (GPS) and inertial measurement unit (IMU) to overlay a SIRE radar image onto a live video stream. We describe a method for transforming 3D world points in the UTM coordinate system onto the video stream by calibrating for the intrinsic parameters of the camera. This calibration is performed offline to save computation time and achieve real time performance. Since the intrinsic parameters are affected by the zoom of the camera, we calibrate at eleven different zooms and interpolate. We show the results of a real time transformation of the SAR imagery onto the video stream. Finally, we quantify both the 2D error and 3D residue associated with our transformation and show that the amount of error is reasonable for our application.

  11. Error Estimation in an Optimal Interpolation Scheme for High Spatial and Temporal Resolution SST Analyses

    NASA Technical Reports Server (NTRS)

    Rigney, Matt; Jedlovec, Gary; LaFontaine, Frank; Shafer, Jaclyn

    2010-01-01

    Heat and moisture exchange between ocean surface and atmosphere plays an integral role in short-term, regional NWP. Current SST products lack both spatial and temporal resolution to accurately capture small-scale features that affect heat and moisture flux. NASA satellite is used to produce high spatial and temporal resolution SST analysis using an OI technique.

  12. Bit-error-rate performance of non-line-of-sight UV transmission with spatial diversity reception.

    PubMed

    Xiao, Houfei; Zuo, Yong; Wu, Jian; Li, Yan; Lin, Jintong

    2012-10-01

    In non-line-of-sight (NLOS) UV communication links using intensity modulation with direct detection, atmospheric turbulence-induced intensity fluctuations can significantly impair link performance. To mitigate turbulence-induced fading and, therefore, to improve the bit error rate (BER) performance, spatial diversity reception can be used over NLOS UV links, which involves the deployment of multiple receivers. The maximum-likelihood (ML) spatial diversity scheme is derived for spatially correlated NLOS UV links, and the influence of various fading correlation at different receivers on the BER performance is investigated. For the dual-receiver case, ML diversity detection is compared with equal gain combining and optimal combining schemes under different turbulence intensity conditions. PMID:23027306

  13. Spatial averaging errors in creating hemispherical reflectance (albedo) maps from directional reflectance data

    SciTech Connect

    Kimes, D.S.; Kerber, A.G.; Sellers, P.J. )

    1993-06-01

    The problems in moving from a radiance measurement made for a particular sun-target-sensor geometry to an accurate estimate of the hemispherical reflectance are considerable. A knowledge-based system called VEG was used in this study to infer hemispherical reflectance. Given directional reflectance(s) and the sun angle, VEG selects the most suitable inference technique(s) and estimates the surface hemispherical reflectance with an estimate of the error. Ideally, VEG is applied to homogeneous vegetation. However, what is typically done in GCM (global circulation model) models and related studies is to obtain an average hemispherical reflectance on a square grid cell on the order of 200 km x 200 km. All available directional data for a given cell are averaged (for each view direction), and then a particular technique for inferring hemispherical reflectance is applied to this averaged data. Any given grid cell can contain several surface types that directionally scatter radiation very differently. When averaging over a set of view angles, the resulting mean values may be atypical of the actual surface types that occur on the ground, and the resulting inferred hemispherical reflectance can be in error. These errors were explored by creating a simulated scene and applying VEG to estimate the area-averaged hemispherical reflectance using various sampling procedures. The reduction in the hemispherical reflectance errors provided by using VEG ranged from a factor of 2-4, depending on conditions. This improvement represents a shift from the calculation of a hemispherical reflectance product of relative value (errors of 20% or more), to a product that could be used quantitatively in global modeling applications, where the requirement is for errors to be limited to around 5-10 %.

  14. Spatial resolution of tropical terrestrial CO2 fluxes inferred using space-borne column CO2 sampled in different earth orbits: the role of spatial error correlations

    NASA Astrophysics Data System (ADS)

    Palmer, P. I.; Feng, L.; Bösch, H.

    2011-09-01

    We use realistic numerical experiments to assess the sensitivity of 8-day CO2 flux estimates, inferred from space-borne short-wave infrared measurements of column-averaged CO2 dry air mixing ratio XCO2, to the choice of Earth observing orbit. We focus on three orbits: (1) a low-inclination circular orbit used by the NASA Tropical Rainfall Measuring Mission (TRMM); (2) a sun-synchronous orbit used by the Japanese Greenhouse Gases Observing SATellite (GOSAT) and proposed for the NASA Orbiting Carbon Observatory (OCO-2) instrument; and (3) a precessing orbit used by the International Space Station (ISS). For each orbit, we assume an instrument based on the specification of the OCO-2; for GOSAT we use the relevant instrument specification. Sun-synchronous orbits offer near global coverage within a few days but have implications for the density of clear-sky measurements. The TRMM and ISS orbits intensively sample tropical latitudes, with sun-lit clear-sky measurements evenly distributed between a.m./p.m. For a specified spatial resolution for inferred fluxes, we show there is a critical number of measurements beyond which there is a disproportionately small decrease in flux uncertainty. We also show that including spatial correlations for measurements and model errors (of length 300 km) reduces the effectiveness of high measurement density for flux estimation, as expected, and so should be considered when deciding sampling strategies. We show that cloud-free data from the TRMM orbit generally can improve the spatial resolution of CO2 fluxes achieved by OCO-2 over tropical South America, for example, from 950 km to 630 km, and that combining data from these low-inclination and sun-synchronous orbits have the potential to reduce this spatial length further. Decreasing the length of the error correlations to 50 km, reflecting anticipated future improvements to transport models, results in CO2 flux estimates on spatial scales that approach those observed by regional

  15. Spatial resolution of tropical terrestrial CO2 fluxes inferred using space-borne column CO2 sampled in different earth orbits: the role of spatial error correlations

    NASA Astrophysics Data System (ADS)

    Palmer, P. I.; Feng, L.; Bösch, H.

    2011-05-01

    We use realistic numerical experiments to assess the sensitivity of 8-day CO2 flux estimates, inferred from space-borne short-wave infrared measurements of column-averaged CO2 dry air mixing ratio XCO2, to the choice of Earth observing orbit. We focus on three orbits: (1) a low-inclination circular orbit used by the NASA Tropical Rainfall Measuring Mission (TRMM); (2) a sun-synchronous orbit used by the Japanese Greenhouse Gases Observing SATellite (GOSAT) and proposed for the NASA Orbiting Carbon Observatory (OCO-2) instrument; and (3) a precessing orbit used by the International Space Station (ISS). For each orbit, we assume an instrument based on the specification of the OCO-2; for GOSAT we use the relevant instrument specification. Sun-synchronous orbits offer near global coverage within a few days but have implications for the density of clear-sky measurements. The TRMM and ISS orbits intensively sample tropical latitudes, with sun-lit clear-sky measurements evenly distributed between a.m./p.m. For a specified spatial resolution for inferred fluxes, we find there is a critical number of measurements beyond which there is a disproportionately small decrease in flux uncertainty. We also find that including spatial correlations for measurements and model errors (of length 300 km) reduces the effectiveness of high measurement density for flux estimation and so should be considered when deciding sampling strategies. We show that cloud-free data from the TRMM orbit generally can improve the spatial resolution of CO2 fluxes achieved by OCO-2 over tropical South America, for example, from 950 km to 630 km, and that combining data from these low-inclination and sun-synchronous orbits have the potential to reduce this spatial length further. Decreasing the length of the error correlations to 50 km, reflecting anticipated future improvements to transport models, results in CO2 flux estimates on spatial scales that approach those observed by regional aircraft.

  16. Error resiliency of distributed video coding in wireless video communication

    NASA Astrophysics Data System (ADS)

    Ye, Shuiming; Ouaret, Mourad; Dufaux, Frederic; Ansorge, Michael; Ebrahimi, Touradj

    2008-08-01

    Distributed Video Coding (DVC) is a new paradigm in video coding, based on the Slepian-Wolf and Wyner-Ziv theorems. DVC offers a number of potential advantages: flexible partitioning of the complexity between the encoder and decoder, robustness to channel errors due to intrinsic joint source-channel coding, codec independent scalability, and multi-view coding without communications between the cameras. In this paper, we evaluate the performance of DVC in an error-prone wireless communication environment. We also present a hybrid spatial and temporal error concealment approach for DVC. Finally, we perform a comparison with a state-of-the-art AVC/H.264 video coding scheme in the presence of transmission errors.

  17. Detecting Changes in Retinal Function: Analysis with Non-Stationary Weibull Error Regression and Spatial Enhancement (ANSWERS)

    PubMed Central

    Zhu, Haogang; Russell, Richard A.; Saunders, Luke J.; Ceccon, Stefano; Garway-Heath, David F.; Crabb, David P.

    2014-01-01

    Visual fields measured with standard automated perimetry are a benchmark test for determining retinal function in ocular pathologies such as glaucoma. Their monitoring over time is crucial in detecting change in disease course and, therefore, in prompting clinical intervention and defining endpoints in clinical trials of new therapies. However, conventional change detection methods do not take into account non-stationary measurement variability or spatial correlation present in these measures. An inferential statistical model, denoted ‘Analysis with Non-Stationary Weibull Error Regression and Spatial enhancement’ (ANSWERS), was proposed. In contrast to commonly used ordinary linear regression models, which assume normally distributed errors, ANSWERS incorporates non-stationary variability modelled as a mixture of Weibull distributions. Spatial correlation of measurements was also included into the model using a Bayesian framework. It was evaluated using a large dataset of visual field measurements acquired from electronic health records, and was compared with other widely used methods for detecting deterioration in retinal function. ANSWERS was able to detect deterioration significantly earlier than conventional methods, at matched false positive rates. Statistical sensitivity in detecting deterioration was also significantly better, especially in short time series. Furthermore, the spatial correlation utilised in ANSWERS was shown to improve the ability to detect deterioration, compared to equivalent models without spatial correlation, especially in short follow-up series. ANSWERS is a new efficient method for detecting changes in retinal function. It allows for better detection of change, more efficient endpoints and can potentially shorten the time in clinical trials for new therapies. PMID:24465636

  18. An Examination of the Spatial Distribution of Carbon Dioxide and Systematic Errors

    NASA Technical Reports Server (NTRS)

    Coffey, Brennan; Gunson, Mike; Frankenberg, Christian; Osterman, Greg

    2011-01-01

    The industrial period and modern age is characterized by combustion of coal, oil, and natural gas for primary energy and transportation leading to rising levels of atmospheric of CO2. This increase, which is being carefully measured, has ramifications throughout the biological world. Through remote sensing, it is possible to measure how many molecules of CO2 lie in a defined column of air. However, other gases and particles are present in the atmosphere, such as aerosols and water, which make such measurements more complicated1. Understanding the detailed geometry and path length of the observation is vital to computing the concentration of CO2. Comparing these satellite readings with ground-truth data (TCCON) the systematic errors arising from these sources can be assessed. Once the error is understood, it can be scaled for in the retrieval algorithms to create a set of data, which is closer to the TCCON measurements1. Using this process, the algorithms are being developed to reduce bias, within.1% worldwide of the true value. At this stage, the accuracy is within 1%, but through correcting small errors contained in the algorithms, such as accounting for the scattering of sunlight, the desired accuracy can be achieved.

  19. Instability in spatial error models: an application to the hypothesis of convergence in the European case

    NASA Astrophysics Data System (ADS)

    Mur, Jesús; López, Fernando; Angulo, Ana

    2010-09-01

    This paper focuses on the hypothesis of stability in the mechanisms of spatial dependence that are usually employed in spatial econometric models. We propose a specification strategy for which the first step is to solve a local estimation algorithm, called the Zoom estimation. The aim of this stage is to detect problems of heterogeneity in the parameters and to identify the regimes. Then we resort to a battery of formal Lagrange Multipliers to test the assumption of stability in the processes of spatial dependence. The alternative hypothesis consists of the existence of several regimes in these parameters. A small Monte Carlo serves to confirm the behaviour of this strategy in a context of finite size samples. As an illustration, we solve an application to the case of the hypothesis of convergence for the per capita income in the European regions. Our results reveal the existence of a strong Centre-Periphery dichotomy in which instability extends to all the elements (coefficients of regression as well as parameters of spatial dependence) that intervene in a classical conditional β-convergence model.

  20. Real-time detection of concealed chemical hazards under ambient light conditions using Raman spectroscopy.

    PubMed

    Cletus, Biju; Olds, William; Fredericks, Peter M; Jaatinen, Esa; Izake, Emad L

    2013-07-01

    Current concerns regarding terrorism and international crime highlight the need for new techniques for detecting unknown and hazardous substances. A novel Raman spectroscopy-based technique, spatially offset Raman spectroscopy (SORS), was recently devised for noninvasively probing the contents of diffusely scattering and opaque containers. Here, we demonstrate a modified portable SORS sensor for detecting concealed substances in-field under different background lighting conditions. Samples including explosive precursors, drugs, and an organophosphate insecticide (chemical warfare agent surrogate) were concealed inside diffusely scattering packaging including plastic, paper, and cloth. Measurements were carried out under incandescent and fluorescent light as well as under daylight to assess the suitability of the probe for different real-life conditions. In each case, it was possible to identify the substances against their reference Raman spectra in less than 1 min. The developed sensor has potential for rapid detection of concealed hazardous substances in airports, mail distribution centers, and customs checkpoints. PMID:23692353

  1. Concealed weapons detection using low-frequency magnetic imaging

    NASA Astrophysics Data System (ADS)

    Zollars, Byron G.; Sallee, Bradley; Durrett, Michael G.; Cruce, Clay; Hallidy, William

    1997-02-01

    Military personnel, law-enforcement officers, and civilians face ever-increasing dangers from persons carrying concealed handguns and other weapons. In direct correspondence with this danger is a need for more sophisticated means of detecting concealed weapons. We have developed a novel concealed-weapons detector based on the principle of low- frequency magnetic imaging. The detector is configured as a portal, and constructs an image of electrically conductive objects transported through it with a potential spatial resolution of approximately 1 inch. Measurements on a breadboard version of the weapons detector have, to date, yielded a resolution of 2 inches. In operation, magnetic dipole radiation, emitted by transmitting antennas in the perimeter of the portal, is scattered from conductive objects and is picked up by receive antennas, also positioned around the portal. With sufficient measurements, each with a different geometry, a solution to the inverse scattering problem can be found. The result is an image of conductive objects in the detector. The detector is sensitive to all metals, semiconductors, and conductive composites. The measured conductivity image formed by the detector is combined with the video signal from a visible CCD camera to form a composite image of persons transiting the detector portal and the conductive objects they are carrying. Accompanying image recognition software could be used to determine the threat level of objects based upon shape, conductivity, and placement on the person of the carrier, and provide cueing, logging, or alarm functions to the operator if suspect weapons are identified. The low- power, low-frequency emissions from the detector are at levels considered safe to humans and medical implants..

  2. College Students' Reasons for Concealing Suicidal Ideation

    ERIC Educational Resources Information Center

    Burton Denmark, Adryon; Hess, Elaine; Becker, Martin Swanbrow

    2012-01-01

    Self-reported reasons for concealing suicidal ideation were explored using data from a national survey of undergraduate and graduate students: 558 students indicated that they seriously considered attempting suicide during the previous year and did not tell anyone about their suicidal thoughts. Content analysis of students' qualitative responses…

  3. Concealment of Child Sexual Abuse in Sports

    ERIC Educational Resources Information Center

    Hartill, Mike

    2013-01-01

    When the sexual abuse of children is revealed, it is often found that other nonabusing adults were aware of the abuse but failed to act. During the past twenty years or so, the concealment of child sexual abuse (CSA) within organizations has emerged as a key challenge for child protection work. Recent events at Pennsylvania State University (PSU)…

  4. Detecting concealed objects at a checkpoint

    DOEpatents

    McMakin, Douglas L.; Hall, Thomas E.; Sheen, David M.; Severtsen, Ronald H.

    2008-07-29

    Disclosed are systems, methods, devices, and apparatus to interrogate a clothed individual with electromagnetic radiation to determine if a concealed object is being carried. This determination includes establishing data corresponding to an image of the individual with a pair of opposed, semi-cylindrical array panels each configured to interrogate the individual with electromagnetic radiation in the 200 MHz to 1 THz range.

  5. Automated Human Screening for Detecting Concealed Knowledge

    ERIC Educational Resources Information Center

    Twyman, Nathan W.

    2012-01-01

    Screening individuals for concealed knowledge has traditionally been the purview of professional interrogators investigating a crime. But the ability to detect when a person is hiding important information would be of high value to many other fields and functions. This dissertation proposes design principles for and reports on an implementation…

  6. Manifest and concealed correlations in quantum mechanics

    NASA Astrophysics Data System (ADS)

    de la Torre, A. C.; Iguain, J. L.

    1998-11-01

    The quantum covariance function is used to study correlations in quantum systems. Besides the obvious correlations due to the conservation of some quantity, the appearance of concealed quantum correlations like non-locality or non-separability is studied. The choice of an appropriate basis allows a complete analysis relating correlations with conservation laws and factorizability.

  7. Concealed Questions. In Search of Answers

    ERIC Educational Resources Information Center

    Frana, Ilaria

    2010-01-01

    This dissertation examines the semantic interpretation of various types of DPs in so-called concealed-question (CQ) constructions, as "Bill's phone number" in the sentence "John knows Bill's phone number". The peculiar characteristic of DP-CQs is that they are interpreted as having the meaning of an embedded question. So, for instance, the…

  8. Student Attitudes Toward Concealed Handguns on Campus at 2 Universities

    PubMed Central

    Bouffard, Jeffrey A.; Wells, William; Nobles, Matt R.

    2012-01-01

    We examined student support for a policy that would allow carrying of concealed handguns on university campuses. Large percentages of students at 2 universities expressed very low levels of comfort with the idea of permitting concealed handgun carrying on campus, suggesting that students may not welcome less restrictive policies. Students held slightly different opinions about concealed handguns on and off campus, suggesting that they view the campus environment as unique with respect to concealed handgun carrying. PMID:22720763

  9. An analysis of perceptual errors in reading mammograms using quasi-local spatial frequency spectra.

    PubMed

    Mello-Thoms, C; Dunn, S M; Nodine, C F; Kundel, H L

    2001-09-01

    In this pilot study the authors examined areas on a mammogram that attracted the visual attention of experienced mammographers and mammography fellows, as well as areas that were reported to contain a malignant lesion, and, based on their spatial frequency spectrum, they characterized these areas by the type of decision outcome that they yielded: true-positives (TP), false-positives (FP), true-negatives (TN), and false-negatives (FN). Five 2-view (craniocaudal and medial-lateral oblique) mammogram cases were examined by 8 experienced observers, and the eye position of the observers was tracked. The observers were asked to report the location and nature of any malignant lesions present in the case. The authors analyzed each area in which either the observer made a decision or in which the observer had prolonged (>1,000 ms) visual dwell using wavelet packets, and characterized these areas in terms of the energy contents of each spatial frequency band. It was shown that each decision outcome is characterized by a specific profile in the spatial frequency domain, and that these profiles are significantly different from one another. As a consequence of these differences, the profiles can be used to determine which type of decision a given observer will make when examining the area. Computer-assisted perception correctly predicted up to 64% of the TPs made by the observers, 77% of the FPs, and 70% of the TNs. PMID:11720333

  10. Modelling static 3-D spatial background error covariances - the effect of vertical and horizontal transform order

    NASA Astrophysics Data System (ADS)

    Wlasak, M. A.; Cullen, M. J. P.

    2014-06-01

    A major difference in the formulation of the univariate part of static background error covariance models for use in global operational 4DVAR arises from the order in which the horizontal and vertical transforms are applied. This is because the atmosphere is non-separable with large horizontal scales generally tied to large vertical scales and small horizontal scales tied to small vertical scales. Also horizontal length scales increase dramatically as one enters the stratosphere. A study is presented which evaluates the strengths and weaknesses of each approach with the Met Office Unified Model. It is shown that if the vertical transform is applied as a function of horizontal wavenumber then the horizontal globally-averaged variance and the homogenous, isotropic length scale on each model level for each control variable of the training data is preserved by the covariance model. In addition the wind variance and associated length scales are preserved as the scheme preserves the variances and length scales of horizontal derivatives. If the vertical transform is applied in physical space, it is possible to make it a function of latitude at the cost of not preserving the variances and length scales of the horizontal derivatives. Summer and winter global 4DVAR trials have been run with both background error covariance models. A clear benefit is seen in the fit to observations when the vertical transform is in spectral space and is a function of total horizontal wavenumber.

  11. 25 CFR 11.444 - Carrying concealed weapons.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Carrying concealed weapons. 11.444 Section 11.444 Indians... ORDER CODE Criminal Offenses § 11.444 Carrying concealed weapons. A person who goes about in public places armed with a dangerous weapon concealed upon his or her person is guilty of a misdemeanor...

  12. 25 CFR 11.444 - Carrying concealed weapons.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Carrying concealed weapons. 11.444 Section 11.444 Indians... ORDER CODE Criminal Offenses § 11.444 Carrying concealed weapons. A person who goes about in public places armed with a dangerous weapon concealed upon his or her person is guilty of a misdemeanor...

  13. 25 CFR 11.444 - Carrying concealed weapons.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Carrying concealed weapons. 11.444 Section 11.444 Indians... ORDER CODE Criminal Offenses § 11.444 Carrying concealed weapons. A person who goes about in public places armed with a dangerous weapon concealed upon his or her person is guilty of a misdemeanor...

  14. 25 CFR 11.444 - Carrying concealed weapons.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Carrying concealed weapons. 11.444 Section 11.444 Indians... ORDER CODE Criminal Offenses § 11.444 Carrying concealed weapons. A person who goes about in public places armed with a dangerous weapon concealed upon his or her person is guilty of a misdemeanor...

  15. 25 CFR 11.444 - Carrying concealed weapons.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Carrying concealed weapons. 11.444 Section 11.444 Indians... ORDER CODE Criminal Offenses § 11.444 Carrying concealed weapons. A person who goes about in public places armed with a dangerous weapon concealed upon his or her person is guilty of a misdemeanor...

  16. Direct recording of concealed ventricular extrasystoles producing pacer inhibition.

    PubMed

    Bowers, Mark; Berger, Marcie

    2013-10-01

    We report a case of concealed extrasystoles recorded from a pacing lead. The concealed extrasystoles were observed with right ventricular pacing, biventricular unipolar, and biventricular bipolar pacing. The simultaneous surface EKG did not show manifest ventricular extrasystoles with the concealed intracardiac potentials. This case highlights a cause of oversensing that has been theoretically reported in the literature but never directly observed. PMID:23600888

  17. The effect of spatial truncation error on variance of gravity anomalies derived from inversion of satellite orbital and gradiometric data

    NASA Astrophysics Data System (ADS)

    Eshagh, Mehdi; Ghorbannia, Morteza

    2014-07-01

    The spatial truncation error (STE) is a significant systematic error in the integral inversion of satellite gradiometric and orbital data to gravity anomalies at sea level. In order to reduce the effect of STE, a larger area than the desired one is considered in the inversion process, but the anomalies located in its central part are selected as the final results. The STE influences the variance of the results as well because the residual vector, which is contaminated with STE, is used for its estimation. The situation is even more complicated in variance component estimation because of its iterative nature. In this paper, we present a strategy to reduce the effect of STE on the a posteriori variance factor and the variance components for inversion of satellite orbital and gradiometric data to gravity anomalies at sea level. The idea is to define two windowing matrices for reducing this error from the estimated residuals and anomalies. Our simulation studies over Fennoscandia show that the differences between the 0.5°×0.5° gravity anomalies obtained from orbital data and an existing gravity model have standard deviation (STD) and root mean squared error (RMSE) of 10.9 and 12.1 mGal, respectively, and those obtained from gradiometric data have 7.9 and 10.1 in the same units. In the case that they are combined using windowed variance components the STD and RMSE become 6.1 and 8.4 mGal. Also, the mean value of the estimated RMSE after using the windowed variances is in agreement with the RMSE of the differences between the estimated anomalies and those obtained from the gravity model.

  18. Induction detection of concealed bulk banknotes

    NASA Astrophysics Data System (ADS)

    Fuller, Christopher; Chen, Antao

    2012-06-01

    The smuggling of bulk cash across borders is a serious issue that has increased in recent years. In an effort to curb the illegal transport of large numbers of paper bills, a detection scheme has been developed, based on the magnetic characteristics of bank notes. The results show that volumes of paper currency can be detected through common concealing materials such as plastics, cardboard, and fabrics making it a possible potential addition to border security methods. The detection scheme holds the potential of also reducing or eliminating false positives caused by metallic materials found in the vicinity, by observing the stark difference in received signals caused by metal and currency. The detection scheme holds the potential to detect for both the presence and number of concealed bulk notes, while maintaining the ability to reduce false positives caused by metal objects.

  19. Concealed weapons detection using electromagnetic resonances

    NASA Astrophysics Data System (ADS)

    Hunt, Allen R.; Hogg, R. Douglas; Foreman, William

    1998-12-01

    Concealed weapons pose a significant threat to both law enforcement and security agency personnel. The uncontrolled environments associated with peacekeeping and the move toward relaxation of concealed weapons laws here in the U.S. provide a strong motivation for developing weapons detection technologies which are noninvasive and can function noncooperatively. Existing weapons detection systems are primarily oriented to detecting metal and require the cooperation of the person being searched. The new generation of detectors under development that focuses primarily on imaging methods, faces problems associated with privacy issues. There remains a need for a weapons detector which is portable, detects weapons remotely, avoids the issues associated with privacy rights, can tell the difference between car keys and a knife, and is affordable enough that one can be issued to every peacekeeper and law enforcement officer. AKELA is developing a concealed weapons detector that uses wideband radar techniques to excite natural electromagnetic resonances that characterize the size, shape, and material composition of an object. Neural network processing is used to classify the difference between weapons and nuisance objects. We have constructed both time and frequency domain test systems and used them to gather experimental data on a variety of armed and unarmed individuals. These experiments have been performed in an environment similar to the operational environment. Preliminary results from these experiments show that it is possible to detect a weapon being carried by an individual from a distance of 10 to 15 feet, and to detect a weapon being concealed behind the back. The power required is about 100 milliwatts. A breadboard system is being fabricated and will be used by AKELA and our law enforcement partner to gather data in operationally realistic situations. While a laptop computer will control the breadboard system, the wideband radar electronics will fit in a box the

  20. A modified surgical procedure for concealed penis

    PubMed Central

    Cheng, Gong; Liu, Bianjiang; Guan, Zhaolong; Huang, Yuan; Qin, Chao; Song, Ninghong; Wang, Zengjun

    2015-01-01

    Introduction: We described a modified surgical procedure for repairing a concealed penis and compared the efficacy and feasibility of modified repair with traditional repair. Methods: From March 2003 to December 2012, 96 patients with a concealed penis were recruited to undergo penile repair at our centre. Modified repair and traditional repair were performed respectively on 46 and 50 cases. We compared operative time, intraoperative blood loss, cosmetic result of operative scars, postoperative penile retraction, and complications. Results: All operations were completed successfully without serious complications. The mean operative time, intraoperative blood loss, and cosmetic result of the operative scar between the two surgical methods were similar. However, the postoperative penile retraction rate in patients undergoing modified repair decreased significantly than in the traditional repair. Conclusions: Our modified surgical procedure is effective and feasible for a concealed penis. Although extra procedures were needed for the modified repair, the operative time, intraoperative blood loss and cosmetic result of operative scar between the two procedures were similar. Compared with traditional repair, modified repair has better clinical outcomes. PMID:26664507

  1. Internally concealed cocaine: analytical and diagnostic aspects.

    PubMed

    Bogusz, M J; Althoff, H; Erkens, M; Maier, R D; Hofmann, R

    1995-09-01

    Thirty persons arrested at Frankfurt airport for smuggling internally concealed cocaine in 1993/1994 were investigated. An X-ray examination (in all 30 cases), immunochemical examination of urine (in 27 cases) and of saliva (in 20 cases) was performed in parallel. An X-ray examination gave positive results in all examined persons. EMIT cocaine metabolite assay (cut off 300 ng benzoylecgonine (BE)/mL) was positive in eight urine samples. After reducing the cut off to 150 ng BE/mL urine, eleven samples were classified as positive. The results were confirmed by means of chromatographic determinations. These findings showed limited role of immunological examination of urine as a screening test in suspected smuggling of internally concealed drugs. All saliva samples showed negative immunochemical results. The number of concealed containers ranged from 44 to 135 per person. The amount of cocaine hydrochloride found in particular cases ranged from 242 to 1050 g net weight, divided into containers weighing from 5.7 to 13.8 g. Drug packages were obviously machine-made. The packages smuggled by a particular person were uniform. However, a distinct interpersonal variability in drug packages was observed, in regard to the number of protective layers (4-7), size, weight, and cocaine purity. This may be helpful for the identification of production site. The leaching of cocaine from selected containers was investigated in a stirring bath and was independent of the conditions applied. PMID:7595327

  2. Imaging sensor fusion for concealed weapon detection

    NASA Astrophysics Data System (ADS)

    Currie, Nicholas C.; Demma, Fred J.; Ferris, David D., Jr.; McMillan, Robert W.; Wicks, Michael C.; Zyga, Kathleen

    1997-02-01

    Sensors are needed for concealed weapon detection which perform better with regard to weapon classification, identification, probability of detection and false alarm rate than the magnetic sensors commonly used in airports. We have concluded that no single sensor will meet the requirements for a reliable concealed weapon detector and thus that sensor fusion is required to optimize detection probability and false alarm rate by combining sensor outputs in a synergistic fashion. This paper describes microwave, millimeter wave, far infrared, infrared, x-ray, acoustic, and magnetic sensors which have some promise in the field of concealed weapon detection. The strengths and weaknesses of these devices are discussed, and examples of the outputs of most of them are given. Various approaches to fusion of these sensors are also described, from simple cuing of one sensor by another to improvement of image quality by using multiple systems. It is further concluded that none of the sensors described herein will ever replace entirely the airport metal detector, but that many of them meet needs imposed by applications requiring a higher detection probability and lower false alarm rate.

  3. Monte carlo method for the uncertainty evaluation of spatial straightness error based on new generation geometrical product specification

    NASA Astrophysics Data System (ADS)

    Wen, Xiulan; Xu, Youxiong; Li, Hongsheng; Wang, Fenglin; Sheng, Danghong

    2012-09-01

    Straightness error is an important parameter in measuring high-precision shafts. New generation geometrical product specification(GPS) requires the measurement uncertainty characterizing the reliability of the results should be given together when the measurement result is given. Nowadays most researches on straightness focus on error calculation and only several research projects evaluate the measurement uncertainty based on "The Guide to the Expression of Uncertainty in Measurement(GUM)". In order to compute spatial straightness error(SSE) accurately and rapidly and overcome the limitations of GUM, a quasi particle swarm optimization(QPSO) is proposed to solve the minimum zone SSE and Monte Carlo Method(MCM) is developed to estimate the measurement uncertainty. The mathematical model of minimum zone SSE is formulated. In QPSO quasi-random sequences are applied to the generation of the initial position and velocity of particles and their velocities are modified by the constriction factor approach. The flow of measurement uncertainty evaluation based on MCM is proposed, where the heart is repeatedly sampling from the probability density function(PDF) for every input quantity and evaluating the model in each case. The minimum zone SSE of a shaft measured on a Coordinate Measuring Machine(CMM) is calculated by QPSO and the measurement uncertainty is evaluated by MCM on the basis of analyzing the uncertainty contributors. The results show that the uncertainty directly influences the product judgment result. Therefore it is scientific and reasonable to consider the influence of the uncertainty in judging whether the parts are accepted or rejected, especially for those located in the uncertainty zone. The proposed method is especially suitable when the PDF of the measurand cannot adequately be approximated by a Gaussian distribution or a scaled and shifted t-distribution and the measurement model is non-linear.

  4. Failure to paint the left quarter of a watercolor and no error in a line drawing: a case report of an art teacher with unilateral spatial neglect.

    PubMed

    Kondo, Minako; Mori, Toshiko; Makino, Kenichiro; Okazaki, Tetsuya; Hachisuka, Kenji

    2012-06-01

    A 54-year-old art teacher, experienced a right putaminal hemorrhage, and thereafter suffered severe left hemiplegia and unilateral spatial neglect, and was transferred to the rehabilitation department of the University Hospital 1 month after the onset. Although the unilateral spatial neglect was improving, the patient was unable to paint the left quarter of a watercolor, but there was no error in line drawing. The occurrence of errors only in a watercolor suggests that the neural process for painting a watercolor is different from that of line drawing. PMID:21936640

  5. Detailed calculation of spectral noise caused by measurement errors of Mach-Zehnder interferometer optical path phases in a spatial heterodyne spectrometer with a phase shift scheme.

    PubMed

    Takada, Kazumasa; Seino, Mitsuyoshi; Chiba, Akito; Okamoto, Katsunari

    2013-04-20

    We calculate the root mean square (rms) value of the spectral noise caused by optical path phase measurement errors in a spatial heterodyne spectrometer (SHS) featuring a complex Fourier transformation. In our calculation the deviated phases of each Mach-Zehnder interferometer in the in-phase and quadrature states are treated as statistically independent random variables. We show that the rms value is proportional to the rms error of the phase measurement and that the proportionality coefficient is given analytically. The relationship enables us to estimate the potential performance of the SHS such as the sidelobe suppression ratio for a given measurement error. PMID:23669661

  6. Detecting persons concealed in a vehicle

    DOEpatents

    Tucker, Jr., Raymond W.

    2005-03-29

    An improved method for detecting the presence of humans or animals concealed within in a vehicle uses a combination of the continuous wavelet transform and a ratio-based energy calculation to determine whether the motion detected using seismic sensors placed on the vehicle is due to the presence of a heartbeat within the vehicle or is the result of motion caused by external factors such as the wind. The method performs well in the presence of light to moderate ambient wind levels, producing far fewer false alarm indications. The new method significantly improves the range of ambient environmental conditions under which human presence detection systems can reliably operate.

  7. Forward error correction and spatial diversity techniques for high-data-rate MILSATCOM over a slow-fading, nuclear-disturbed channel

    NASA Astrophysics Data System (ADS)

    Paul, Heywood I.; Meader, Charles B.; Lyons, Daniel A.; Ayers, David R.

    Forward error correction (FEC) and spatial diversity techniques are considered for improving the reliability of high-data-rate military satellite communication (MILSATCOM) over a slow-fading, nuclear-disturbed channel. Slow fading, which occurs when the channel decorrelation time is much greater than the transmitted symbol interval, is characterized by deep fades and, without special precautions, long bursts of errors over high-data-rate communication links. Using the widely accepted Defense Nuclear Agency (DNA) nuclear-scintillated channel model, the authors derive performance tradeoffs among required interleaver storage, FEC, spatial diversity, and link signal-to-noise ratio for differential binary phase shift keying (DBPSK) in the slow-fading environment. Spatial diversity is found to yield impressive gains without the large memory storage and transmission relay requirements associated with interleaving.

  8. Millimeter-wave concealed weapon detection

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Wen; Juhola, Markku; Grainger, William; Wang, Beining; Manahan, Brian

    1997-02-01

    Millimeter-wave concealed weapon detection, based on the use of a fast scan short-range FMCW 94 GHz radar, was evaluated in a small business innovative research phase I under the Technology Reinvestment Project (TRP) program. The feasibility of a fast circular scan technique invented by Chang Industry has been firmly established, with handgun images recorded. This fast scan technique is essential both for remote sensing and full-body fixed site scanner applications. Although only raw image data was obtained in Phase I, we propose to apply super-resolution image enhancements and target recognition software algorithms to provide more reliable detection. Endorsement from the Los Angeles County Sheriff's Department, to provide operational input and testing and evaluation, and the hiring of a consultant to plan for future program financing (including venture capital investment) make the project very attractive for commercialization.

  9. Prime number variant of concealed trigeminy.

    PubMed

    Medeiros, C M; Medeiros, N P; de Nonohay, N C; Rodrigues, R

    1985-10-01

    A 53-year-old man with myocardial infarction was found to have frequent premature ventricular beats. The predominant pattern was classical concealed trigeminy; i.e., the number of conducted sinus beats, S, between extrasystoles satisfied the equation S = 3n + 2, where "n" is zero or any positive integer. Two other transient patterns also occurred. The first one was characterized by exceptional values of S, which satisfied the equation S = 3n + 3. In the second transient pattern, all values of S fitted the classical equation, but there were singularly absent values; i.e., the "n" in the equation was exclusively an odd number, giving rise to only prime numbers of interectopic conducted sinus beats. It is proposed in this last form that there are two sites of fixed block proximal to a variable distal block in a re-entry loop responsible for the ventricular extrasystoles. PMID:2415650

  10. Induction detection of concealed bulk banknotes

    NASA Astrophysics Data System (ADS)

    Fuller, Christopher; Chen, Antao

    2011-10-01

    Bulk cash smuggling is a serious issue that has grown in volume in recent years. By building on the magnetic characteristics of paper currency, induction sensing is found to be capable of quickly detecting large masses of banknotes. The results show that this method is effective in detecting bulk cash through concealing materials such as plastics, cardboards, fabrics and aluminum foil. The significant difference in the observed phase between the received signals caused by conducting materials and ferrite compounds, found in banknotes, provides a good indication that this process can overcome the interference by metal objects in a real sensing application. This identification strategy has the potential to not only detect the presence of banknotes, but also the number, while still eliminating false positives caused by metal objects.

  11. Concealed semantic and episodic autobiographical memory electrified

    PubMed Central

    Ganis, Giorgio; Schendan, Haline E.

    2013-01-01

    Electrophysiology-based concealed information tests (CIT) try to determine whether somebody possesses concealed information about a crime-related item (probe) by comparing event-related potentials (ERPs) between this item and comparison items (irrelevants). Although the broader field is sometimes referred to as “memory detection,” little attention has been paid to the precise type of underlying memory involved. This study begins addressing this issue by examining the key distinction between semantic and episodic memory in the autobiographical domain within a CIT paradigm. This study also addresses the issue of whether multiple repetitions of the items over the course of the session habituate the brain responses. Participants were tested in a 3-stimulus CIT with semantic autobiographical probes (their own date of birth) and episodic autobiographical probes (a secret date learned just before the study). Results dissociated these two memory conditions on several ERP components. Semantic probes elicited a smaller frontal N2 than episodic probes, consistent with the idea that the frontal N2 decreases with greater pre-existing knowledge about the item. Likewise, semantic probes elicited a smaller central N400 than episodic probes. Semantic probes also elicited a larger P3b than episodic probes because of their richer meaning. In contrast, episodic probes elicited a larger late positive complex (LPC) than semantic probes, because of the recent episodic memory associated with them. All these ERPs showed a difference between probes and irrelevants in both memory conditions, except for the N400, which showed a difference only in the semantic condition. Finally, although repetition affected the ERPs, it did not reduce the difference between probes and irrelevants. These findings show that the type of memory associated with a probe has both theoretical and practical importance for CIT research. PMID:23355816

  12. Color image fusion for concealed weapon detection

    NASA Astrophysics Data System (ADS)

    Toet, Alexander

    2003-09-01

    Recent advances in passive and active imaging sensor technology offer the potential to detect weapons that are concealed underneath a person's clothing or carried along in bags. Although the concealed weapons can sometimes easily be detected, it can be difficult to perceive their context, due to the non-literal nature of these images. Especially for dynamic crowd surveillance purposes it may be impossible to rapidly asses with certainty which individual in the crowd is the one carrying the observed weapon. Sensor fusion is an enabling technology that may be used to solve this problem. Through fusion the signal of the sensor that depicts the weapon can be displayed in the context provided by a sensor of a different modality. We propose an image fusion scheme in which non-literal imagery can be fused with standard color images such that the result clearly displays the observed weapons in the context of the original color image. The procedure is such that the relevant contrast details from the non-literal image are transferred to the color image without altering the original color distribution of this image. The result is a natural looking color image that fluently combines all details from both input sources. When an observer who performs a dynamic crowd surveillance task, detects a weapon in the scene, he will also be able to quickly determine which person in the crowd is actually carrying the observed weapon (e.g. "the man with the red T-shirt and blue jeans"). The method is illustrated by the fusion of thermal 8-12 μm imagery with standard RGB color images.

  13. Concealing their communication: exploring psychosocial predictors of young drivers' intentions and engagement in concealed texting.

    PubMed

    Gauld, Cassandra S; Lewis, Ioni; White, Katherine M

    2014-01-01

    Making a conscious effort to hide the fact that you are texting while driving (i.e., concealed texting) is a deliberate and risky behaviour involving attention diverted away from the road. As the most frequent users of text messaging services and mobile phones while driving, young people appear at heightened risk of crashing from engaging in this behaviour. This study investigated the phenomenon of concealed texting while driving, and utilised an extended Theory of Planned Behaviour (TPB) including the additional predictors of moral norm, mobile phone involvement, and anticipated regret to predict young drivers' intentions and subsequent behaviour. Participants (n=171) were aged 17-25 years, owned a mobile phone, and had a current driver's licence. Participants completed a questionnaire measuring their intention to conceal texting while driving, and a follow-up questionnaire a week later to report their behavioural engagement. The results of hierarchical multiple regression analyses showed overall support for the predictive utility of the TPB with the standard constructs accounting for 69% of variance in drivers' intentions, and the extended predictors contributing an additional 6% of variance in intentions over and above the standard constructs. Attitude, subjective norm, PBC, moral norm, and mobile phone involvement emerged as significant predictors of intentions; and intention was the only significant predictor of drivers' self-reported behaviour. These constructs can provide insight into key focal points for countermeasures including advertising and other public education strategies aimed at influencing young drivers to reconsider their engagement in this risky behaviour. PMID:24211560

  14. Concealing Concealment: The Mediating Role of Internalized Heterosexism in Psychological Distress Among Lesbian, Gay, and Bisexual Older Adults

    PubMed Central

    Hoy-Ellis, Charles P.

    2016-01-01

    Recent population-based studies indicate that sexual minorities aged 50 and older experience significantly higher rates of psychological distress than their heterosexual age-peers. The minority stress model has been useful in explaining disparately high rates of psychological distress among younger sexual minorities. The purpose of this study is to test a hypothesized structural relationship between two minority stressors—internalized heterosexism and concealment of sexual orientation—and consequent psychological distress among a sample of 2,349 lesbian, gay, and bisexual adults aged 50 to 95 years old. Structural equation modeling indicates that concealment has a nonsignificant direct effect on psychological distress but a significant indirect effect that is mediated through internalized heterosexism; the effect of concealment is itself concealed. This may explain divergent results regarding the role of concealment in psychological distress in other studies, and the implications will be discussed. PMID:26322654

  15. Concealed identification symbols and nondestructive determination of the identification symbols

    DOEpatents

    Nance, Thomas A.; Gibbs, Kenneth M.

    2014-09-16

    The concealing of one or more identification symbols into a target object and the subsequent determination or reading of such symbols through non-destructive testing is described. The symbols can be concealed in a manner so that they are not visible to the human eye and/or cannot be readily revealed to the human eye without damage or destruction of the target object. The identification symbols can be determined after concealment by e.g., the compilation of multiple X-ray images. As such, the present invention can also provide e.g., a deterrent to theft and the recovery of lost or stolen objects.

  16. Covert respiration measures for the detection of concealed information.

    PubMed

    Elaad, Eitan; Ben-Shakhar, Gershon

    2008-03-01

    A mock-theft experiment was designed to assess the efficiency of two covert respiration measures in detection of concealed information. The covert measures were further compared with three standard measures typically used for the detection of concealed knowledge (electrodermal, respiration and finger pulse measures). Results revealed that the covert respiration measures produced good discrimination between "guilty" (participants possessing concealed knowledge) and "innocent" participants. One of the covert measures produced detection efficiency that was similar to that of the standard respiration and finger pulse measures, but less than the electrodermal measure. PMID:18093718

  17. Concealable Stigmatized Identities and Psychological Well-Being

    PubMed Central

    Quinn, Diane M.; Earnshaw, Valerie A.

    2013-01-01

    Many people have concealable stigmatized identities: Identities that can be hidden from others and that are socially devalued and negatively stereotyped. Understanding how these concealable stigmatized identities affect psychological well-being is critical. We present our model of the components of concealable stigmatized identities including valenced content – internalized stigma, experienced discrimination, anticipated stigma, disclosure reactions, and counter-stereotypic/positive information – and magnitude – centrality and salience. Research has shown that negatively valenced content is related to increased psychological distress. However, smaller identity magnitude may buffer this distress. We review the research available and discuss important areas for future work. PMID:23730326

  18. Approach trajectory planning system for maximum concealment

    NASA Technical Reports Server (NTRS)

    Warner, David N., Jr.

    1986-01-01

    A computer-simulation study was undertaken to investigate a maximum concealment guidance technique (pop-up maneuver), which military aircraft may use to capture a glide path from masked, low-altitude flight typical of terrain following/terrain avoidance flight enroute. The guidance system applied to this problem is the Fuel Conservative Guidance System. Previous studies using this system have concentrated on the saving of fuel in basically conventional land and ship-based operations. Because this system is based on energy-management concepts, it also has direct application to the pop-up approach which exploits aircraft performance. Although the algorithm was initially designed to reduce fuel consumption, the commanded deceleration is at its upper limit during the pop-up and, therefore, is a good approximation of a minimum-time solution. Using the model of a powered-lift aircraft, the results of the study demonstrated that guidance commands generated by the system are well within the capability of an automatic flight-control system. Results for several initial approach conditions are presented.

  19. Improving the spatial and temporal resolution with quantification of uncertainty and errors in earth observation data sets using Data Interpolating Empirical Orthogonal Functions methodology

    NASA Astrophysics Data System (ADS)

    El Serafy, Ghada; Gaytan Aguilar, Sandra; Ziemba, Alexander

    2016-04-01

    There is an increasing use of process-based models in the investigation of ecological systems and scenario predictions. The accuracy and quality of these models are improved when run with high spatial and temporal resolution data sets. However, ecological data can often be difficult to collect which manifests itself through irregularities in the spatial and temporal domain of these data sets. Through the use of Data INterpolating Empirical Orthogonal Functions(DINEOF) methodology, earth observation products can be improved to have full spatial coverage within the desired domain as well as increased temporal resolution to daily and weekly time step, those frequently required by process-based models[1]. The DINEOF methodology results in a degree of error being affixed to the refined data product. In order to determine the degree of error introduced through this process, the suspended particulate matter and chlorophyll-a data from MERIS is used with DINEOF to produce high resolution products for the Wadden Sea. These new data sets are then compared with in-situ and other data sources to determine the error. Also, artificial cloud cover scenarios are conducted in order to substantiate the findings from MERIS data experiments. Secondly, the accuracy of DINEOF is explored to evaluate the variance of the methodology. The degree of accuracy is combined with the overall error produced by the methodology and reported in an assessment of the quality of DINEOF when applied to resolution refinement of chlorophyll-a and suspended particulate matter in the Wadden Sea. References [1] Sirjacobs, D.; Alvera-Azcárate, A.; Barth, A.; Lacroix, G.; Park, Y.; Nechad, B.; Ruddick, K.G.; Beckers, J.-M. (2011). Cloud filling of ocean colour and sea surface temperature remote sensing products over the Southern North Sea by the Data Interpolating Empirical Orthogonal Functions methodology. J. Sea Res. 65(1): 114-130. Dx.doi.org/10.1016/j.seares.2010.08.002

  20. Brain fingerprinting classification concealed information test detects US Navy military medical information with P300

    PubMed Central

    Farwell, Lawrence A.; Richardson, Drew C.; Richardson, Graham M.; Furedy, John J.

    2014-01-01

    A classification concealed information test (CIT) used the “brain fingerprinting” method of applying P300 event-related potential (ERP) in detecting information that is (1) acquired in real life and (2) unique to US Navy experts in military medicine. Military medicine experts and non-experts were asked to push buttons in response to three types of text stimuli. Targets contain known information relevant to military medicine, are identified to subjects as relevant, and require pushing one button. Subjects are told to push another button to all other stimuli. Probes contain concealed information relevant to military medicine, and are not identified to subjects. Irrelevants contain equally plausible, but incorrect/irrelevant information. Error rate was 0%. Median and mean statistical confidences for individual determinations were 99.9% with no indeterminates (results lacking sufficiently high statistical confidence to be classified). We compared error rate and statistical confidence for determinations of both information present and information absent produced by classification CIT (Is a probe ERP more similar to a target or to an irrelevant ERP?) vs. comparison CIT (Does a probe produce a larger ERP than an irrelevant?) using P300 plus the late negative component (LNP; together, P300-MERMER). Comparison CIT produced a significantly higher error rate (20%) and lower statistical confidences: mean 67%; information-absent mean was 28.9%, less than chance (50%). We compared analysis using P300 alone with the P300 + LNP. P300 alone produced the same 0% error rate but significantly lower statistical confidences. These findings add to the evidence that the brain fingerprinting methods as described here provide sufficient conditions to produce less than 1% error rate and greater than 95% median statistical confidence in a CIT on information obtained in the course of real life that is characteristic of individuals with specific training, expertise, or organizational

  1. Brain fingerprinting classification concealed information test detects US Navy military medical information with P300.

    PubMed

    Farwell, Lawrence A; Richardson, Drew C; Richardson, Graham M; Furedy, John J

    2014-01-01

    A classification concealed information test (CIT) used the "brain fingerprinting" method of applying P300 event-related potential (ERP) in detecting information that is (1) acquired in real life and (2) unique to US Navy experts in military medicine. Military medicine experts and non-experts were asked to push buttons in response to three types of text stimuli. Targets contain known information relevant to military medicine, are identified to subjects as relevant, and require pushing one button. Subjects are told to push another button to all other stimuli. Probes contain concealed information relevant to military medicine, and are not identified to subjects. Irrelevants contain equally plausible, but incorrect/irrelevant information. Error rate was 0%. Median and mean statistical confidences for individual determinations were 99.9% with no indeterminates (results lacking sufficiently high statistical confidence to be classified). We compared error rate and statistical confidence for determinations of both information present and information absent produced by classification CIT (Is a probe ERP more similar to a target or to an irrelevant ERP?) vs. comparison CIT (Does a probe produce a larger ERP than an irrelevant?) using P300 plus the late negative component (LNP; together, P300-MERMER). Comparison CIT produced a significantly higher error rate (20%) and lower statistical confidences: mean 67%; information-absent mean was 28.9%, less than chance (50%). We compared analysis using P300 alone with the P300 + LNP. P300 alone produced the same 0% error rate but significantly lower statistical confidences. These findings add to the evidence that the brain fingerprinting methods as described here provide sufficient conditions to produce less than 1% error rate and greater than 95% median statistical confidence in a CIT on information obtained in the course of real life that is characteristic of individuals with specific training, expertise, or organizational

  2. Analysis of Spatial Smoothing Effect of Short-term Fluctuation of Global Solar Radiation based on the Data Including Quantization Error

    NASA Astrophysics Data System (ADS)

    Ue, Yosuke; Hara, Ryoichi; Kita, Hiroyuki; Saito, Yutaka; Takitani, Katsuyuki; Saito, Masami

    A Photovoltaic (PV) system is expected as one of the promising countermeasures for the global warming and the environmental issues. However, generation output from PV system is generally unstable and unpredictable. Therefore, large penetration of PV systems may cause some serious impacts to the power system operation such as a load frequency control, a voltage regulation, etc. Estimation of the influences of PV system installation is becoming important, however, it requires simultaneous multipoint solar radiation measurements. The Japan Meteorological Business Support Center has provided the 1-min meteorological data observed in Japan, however, its solar radiation data includes quantization errors. This paper proposes a regeneration method for the solar radiation data including quantization errors. This paper also analyses the spatial smoothing effect of the global solar radiation fluctuations.

  3. Assessing representation errors of IAGOS CO2, CO and CH4 profile observations: the impact of spatial variations in near-field emissions

    NASA Astrophysics Data System (ADS)

    Boschetti, Fabio; Thouret, Valerie; Nedelec, Philippe; Chen, Huilin; Gerbig, Christoph

    2015-04-01

    Airborne platforms have their main strength in the ability of collecting mixing ratio and meteorological data at different heights across a vertical profile, allowing an insight in the internal structure of the atmosphere. However, rental airborne platforms are usually expensive, limiting the number of flights that can be afforded and hence on the amount of data that can be collected. To avoid this disadvantage, the MOZAIC/IAGOS (Measurements of Ozone and water vapor by Airbus In-service airCraft/In-service Aircraft for a Global Observing System) program makes use of commercial airliners, providing data on a regular basis. It is therefore considered an important tool in atmospheric investigations. However, due to the nature of said platforms, MOZAIC/IAGOS's profiles are located near international airports, which are usually significant emission sources, and are in most cases close to major urban settlements, characterized by higher anthropogenic emissions compared to rural areas. When running transport models at finite resolution, these local emissions can heavily affect measurements resulting in biases in model/observation mismatch. Model/observation mismatch can include different aspects in both horizontal and vertical direction, for example spatial and temporal resolution of the modeled fluxes, or poorly represented convective transport or turbulent mixing in the boundary layer. In the framework of the IGAS (IAGOS for GMES Atmospheric Service) project, whose aim is to improve connections between data collected by MOZAIC/IAGOS and Copernicus Atmospheric Service, the present study is focused on the effect of the spatial resolution of emission fluxes, referred to here as representation error. To investigate this, the Lagrangian transport model STILT (Stochastic Time Inverted Lagrangian Transport) was coupled with EDGAR (Emission Database for Global Atmospheric Research) version-4.3 emission inventory at European regional scale. EDGAR's simulated fluxes for CO, CO2

  4. Classification of radiological errors in chest radiographs, using support vector machine on the spatial frequency features of false- negative and false-positive regions

    NASA Astrophysics Data System (ADS)

    Pietrzyk, Mariusz W.; Donovan, Tim; Brennan, Patrick C.; Dix, Alan; Manning, David J.

    2011-03-01

    Aim: To optimize automated classification of radiological errors during lung nodule detection from chest radiographs (CxR) using a support vector machine (SVM) run on the spatial frequency features extracted from the local background of selected regions. Background: The majority of the unreported pulmonary nodules are visually detected but not recognized; shown by the prolonged dwell time values at false-negative regions. Similarly, overestimated nodule locations are capturing substantial amounts of foveal attention. Spatial frequency properties of selected local backgrounds are correlated with human observer responses either in terms of accuracy in indicating abnormality position or in the precision of visual sampling the medical images. Methods: Seven radiologists participated in the eye tracking experiments conducted under conditions of pulmonary nodule detection from a set of 20 postero-anterior CxR. The most dwelled locations have been identified and subjected to spatial frequency (SF) analysis. The image-based features of selected ROI were extracted with un-decimated Wavelet Packet Transform. An analysis of variance was run to select SF features and a SVM schema was implemented to classify False-Negative and False-Positive from all ROI. Results: A relative high overall accuracy was obtained for each individually developed Wavelet-SVM algorithm, with over 90% average correct ratio for errors recognition from all prolonged dwell locations. Conclusion: The preliminary results show that combined eye-tracking and image-based features can be used for automated detection of radiological error with SVM. The work is still in progress and not all analytical procedures have been completed, which might have an effect on the specificity of the algorithm.

  5. A technique for estimating spatial sampling errors in coarse-scale soil moisture estimates derived from point-scale observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The validation of satellite surface soil moisture retrievals requires the spatial aggregation of point-scale ground soil moisture measurements up to coarse resolution satellite footprint scales (>10 km). In regions containing a limited number of ground measurements per satellite footprint, a large c...

  6. Attenuation and bit error rate for four co-propagating spatially multiplexed optical communication channels of exactly same wavelength in step index multimode fibers

    NASA Astrophysics Data System (ADS)

    Murshid, Syed H.; Chakravarty, Abhijit

    2011-06-01

    Spatial domain multiplexing (SDM) utilizes co-propagation of exactly the same wavelength in optical fibers to increase the bandwidth by integer multiples. Input signals from multiple independent single mode pigtail laser sources are launched at different input angles into a single multimode carrier fiber. The SDM channels follow helical paths and traverse through the carrier fiber without interfering with each other. The optical energy from the different sources is spatially distributed and takes the form of concentric circular donut shaped rings, where each ring corresponds to an independent laser source. At the output end of the fiber these donut shaped independent channels can be separated either with the help of bulk optics or integrated concentric optical detectors. This presents the experimental setup and results for a four channel SDM system. The attenuation and bit error rate for individual channels of such a system is also presented.

  7. Millimeter-wave imaging for concealed weapon detection

    NASA Astrophysics Data System (ADS)

    McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.

    2003-07-01

    Full body, real-time, millimeter-wave imaging systems have been developed at the Pacific Northwest National Laboratory for the detection of body-worn, concealed weapons and contraband at security checkpoints. These security systems employ methods derived from microwave holography techniques that utilize phase and amplitude information recorded over a two-dimensional aperture to reconstruct a focused image of the target. Millimeter-wave imaging is well suited for the detection of concealed weapons or other contraband carried on personnel, since millimeter waves are non-ionizing, readily penetrate common clothing material, and are reflected from the human body and any concealed items. In this paper, wide-bandwidth, three-dimensional, holographic microwave imaging techniques and a full-body, planar, millimeter-wave imaging system are described.

  8. Millimeter-wave imaging for concealed weapon detection

    SciTech Connect

    McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.

    2003-07-16

    Full-body, real-time, millimeter-wave imaging systems have been developed at the Pacific Northwest National Laboratory for the detection of body-worn, concealed weapons and contraband at security checkpoints. These security systems employ methods derived from microwave holography techniques that utilize phase and amplitude information recorded over a two-dimensional aperture to reconstruct a focused image of the target. Millimeter-wave imaging is well suited for the detection of concealed weapons or other contraband carried on personnel, since millimeter waves are non-ionizing, readily penetrate common clothing material, and are reflected from the human body and any concealed items. In this paper, wide-bandwidth, three-dimensional, holographic microwave imaging techniques and a full-body, planar, millimeter-wave imaging system are described.

  9. Pigmented concealing powders for the hair loss patient.

    PubMed

    Cossman, Jack P; Ladizinski, Barry; Lee, Kachiu C

    2013-12-01

    Patients suffering from alopecia may experience low self-esteem, low self-image, and other psychological consequences. While medical and surgical options for treating hair loss exist, these may be prohibitively expensive or have an unpredictable outcome. In lieu of or in addition to therapeutic approaches, cosmetic options have long been an approach to hair loss. However, patients and clinicians alike often regard cosmetic options to be limited to hairstyling and hairpieces, unaware that newer options, namely pigmented concealing powders, may offer a more practical and seemingly natural camouflage. This article introduces the clinician to concealing powders as a viable option for the hair loss patient. PMID:24305431

  10. Systematic errors of an optical encryption system due to the discrete values of a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Monaghan, David S.

    2009-02-01

    An optical implementation of the amplitude encoded double random phase encryption/decryption technique is implemented, and both numerical and experimental results are presented. In particular, we examine the effect of quantization in the decryption process due to the discrete values and quantized levels, which a spatial light modulator (SLM) can physically display. To do this, we characterize a transmissive SLM using Jones matrices and then map a complex image to the physically achievable levels of the SLM using the pseudorandom encoding technique. We present both numerical and experimental results that quantify the performance of the system.

  11. Influence of rainfall estimation error and spatial variability on sewer flow prediction at a small urban scale

    NASA Astrophysics Data System (ADS)

    Schellart, A. N. A.; Shepherd, W. J.; Saul, A. J.

    2012-09-01

    Legislative drivers for water quality and urban flood risk are driving a growing need to accurately determine the performance of urban drainage systems in near real time. Rainfall data are clearly a key input to urban drainage system models. Historically rain gauge data have been used, however radar rainfall data are now widely available and benefits from significantly higher spatial coverage than rain gauges in most UK urban catchments. This paper describes a detailed study based on a small (11 km2) urban catchment in West Yorkshire, England. Radar and rain gauge data have been compared and used as the input to hydrodynamic sewer flow simulations, and the results of these simulations have been compared with measured flows in the sewer system. The results showed that for this size of catchment, there can be significant differences in simulated peak flows and combined sewer overflow spill volumes due to inherent uncertainties between the two rainfall estimates.

  12. Effects of moderate prenatal ethanol exposure and age on social behavior, spatial response perseveration errors and motor behavior.

    PubMed

    Hamilton, Derek A; Barto, Daniel; Rodriguez, Carlos I; Magcalas, Christy M; Fink, Brandi C; Rice, James P; Bird, Clark W; Davies, Suzy; Savage, Daniel D

    2014-08-01

    Persistent deficits in social behavior are among the major negative consequences associated with exposure to ethanol during prenatal development. Prior work from our laboratory has linked deficits in social behavior following moderate prenatal alcohol exposure (PAE) in the rat to functional alterations in the ventrolateral frontal cortex [21]. In addition to social behaviors, the regions comprising the ventrolateral frontal cortex are critical for diverse processes ranging from orofacial motor movements to flexible alteration of behavior in the face of changing consequences. The broader behavioral implications of altered ventrolateral frontal cortex function following moderate PAE have, however, not been examined. In the present study we evaluated the consequences of moderate PAE on social behavior, tongue protrusion, and flexibility in a variant of the Morris water task that required modification of a well-established spatial response. PAE rats displayed deficits in tongue protrusion, reduced flexibility in the spatial domain, increased wrestling, and decreased investigation, indicating that several behaviors associated with ventrolateral frontal cortex function are impaired following moderate PAE. A linear discriminant analysis revealed that measures of wrestling and tongue protrusion provided the best discrimination of PAE rats from saccharin-exposed control rats. We also evaluated all behaviors in young adult (4-5 months) or older (10-11 months) rats to address the persistence of behavioral deficits in adulthood and possible interactions between early ethanol exposure and advancing age. Behavioral deficits in each domain persisted well into adulthood (10-11 months), however, there was no evidence that aging enhances the effects of moderate PAE within the age ranges that were studied. PMID:24769174

  13. Inverse synthetic aperture radar imaging for concealed object detection on a naturally walking person

    NASA Astrophysics Data System (ADS)

    Zhuravlev, Andrey; Ivashov, Sergey; Razevig, Vladimir; Vasiliev, Igor; Bechtel, Timothy

    2014-05-01

    This paper describes the architecture of a microwave radar system intended for imaging concealed objects under clothing as a subject walks through the inspection area. The system uses the principle of inverse aperture which is achieved by a person's movement past a stationary microwave sensor array. In the system, the vertical resolution is achieved by arranging microwave sensors vertically while the horizontal resolution is due to the subject's horizontal motion. The positioning of the objects is achieved by employing a synchronous video sensor that allows coherent radar signal processing. A possible radar signal processing technique based on signal accumulation is described. Numerical experiments are conducted with the described object trajectory model. The influence of positioning errors attributed to the video positioning system is also modeled numerically. An experimental setup is designed and proposed to evaluate the suggested signal processing techniques on real data with an electro-mechanical scanner and single transceiver. It is suggested that the signal acquisition with the system can be accomplished using the stop motion technique, in which a series of changing stationary scenes is sampled and processed. Experimental radar images are demonstrated for stationary objects with concealed items and considered as reference images. Further development of the system is suggested.

  14. Detecting concealed information using functional near-infrared spectroscopy.

    PubMed

    Sai, Liyang; Zhou, Xiaomei; Ding, Xiao Pan; Fu, Genyue; Sang, Biao

    2014-09-01

    The present study focused on the potential application of fNIRS in the detection of concealed information. Participants either committed a mock crime or not and then were presented with a randomized series of probes (crime-related information) and irrelevants (crime-irrelevant information) in a standard concealed information test (CIT). Participants in the guilty group were instructed to conceal crime-related information they obtained from the mock crime, thus making deceptive response to the probes. Meanwhile, their brain activity to probes and irrelevants was recorded by functional near-infrared spectroscopy (fNIRS). At the group level, we found that probe items were associated with longer reaction times and greater activity in bilateral dorsolateral prefrontal cortex and supplementary motor cortex than irrelevant items in the guilty group, but not in the innocent group. These findings provided evidence on neural correlates of recognition during a CIT. Finally, on the basis of the activity in bilateral dorsolateral prefrontal cortex and supplementary motor cortex, the correct classification of guilty versus innocent participants was approximately 75 % and the combination of fNIRS and reaction time measures yielded a better classification rate of 83.3 %. These findings illustrate the feasibility and promise of using fNIRS to detect concealed information. PMID:24514911

  15. Do Children Understand That People Selectively Conceal or Express Emotion?

    ERIC Educational Resources Information Center

    Hayashi, Hajimu; Shiomi, Yuki

    2015-01-01

    This study examined whether children understand that people selectively conceal or express emotion depending upon the context. We prepared two contexts for a verbal display task for 70 first-graders, 80 third-graders, 64 fifth-graders, and 71 adults. In both contexts, protagonists had negative feelings because of the behavior of the other…

  16. Cylindrical millimeter-wave imaging technique for concealed weapon detection

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; McMakin, Douglas L.; Hall, Thomas E.

    1998-03-01

    A novel cylindrical millimeter-wave imaging technique has been developed at the Pacific Northwest National Laboratory for the detection of metallic and non-metallic concealed weapons. This technique uses a vertical array of millimeter- wave antennas which is mechanically swept around a person in a cylindrical fashion. The wideband millimeter-wave data is mathematically reconstructed into a series of high- resolution images of the person being screened. Clothing is relatively transparent to millimeter-wave illumination,whereas the human body and concealed items are reflective at millimeter wavelengths. Differences in shape and reflectivity are revealed in the images and allow a human operator to detect and identify concealed weapons. A full 360 degree scan is necessary to fully inspect a person for concealed items. The millimeter-wave images can be formed into a video animation sequence in which the person appears to rotate in front of a fixed illumination source.This is s convenient method for presenting the 3D image data for analysis. This work has been fully sponsored by the FAA. An engineering prototype based on the cylindrical imaging technique is presently under development. The FAA is currently opposed to presenting the image data directly to the operator due to personal privacy concerns. A computer automated system is desired to address this problem by eliminating operator viewing of the imagery.

  17. Cycles of abuse nurtured by concealment: a clinical report.

    PubMed

    Wijma, Barbro; Thapar-Björkert, Suruchi; Hammarström, Nevija Cah; Swahnberg, Katarina

    2007-09-01

    At present, health care staff do not seem to have sufficient knowledge about their patients' abusive experiences. The aim of the present study is to analyze and discuss what the implications might be for the encounter between patients and health care professionals, when experiences of abuse are concealed. The methodology of this article is varied: a personal narrative, medical records, sociological theoretical literature and empirical evidence. From the narrative we learn that concealment of abuse was devastating for the patient. She was "treated" in vain as a correct diagnosis was not made, while abuse by her father continued. Health care staff also violated her, which she told her therapist, but her protests were not acknowledged. Ten years of treatment thus made her even more sick. This case story focuses on the mechanisms which nurture concealment of a patient's history of abuse, such as structural and symbolic violence. We also suggest ways to break "cycles of abuse". Help the patient to stop concealing also means that she/he leaves a victim role, gets in charge of the situation and takes a first step towards empowerment. In this way, health care settings can become enabling and empowering environments. PMID:17577758

  18. Adolescent disclosure and concealment: longitudinal and concurrent associations with aggression.

    PubMed

    Leavitt, Chelom E; Nelson, David A; Coyne, Sarah M; Hart, Craig H

    2013-01-01

    This longitudinal study assessed the association between prior (preschool) and concurrent physical and relational aggression as they relate to Russian adolescents' disclosure and concealment patterns with their parents. In the initial preschool study, there were 106 boys and 106 girls (mean age = 60.24 months, SD = 7.81). Both peer nominations and teacher ratings of aggression were obtained for these children. Ten years later, the majority of these children (72.2%; n = 153) completed a longitudinal follow-up battery of assessments. Included in these measures was a self-reported measure of aggression as well as an assessment of the extent to which these adolescents disclosed to and concealed information from their parents. Separate models were estimated by gender of child for the 153 children who participated in both Time 1 and Time 2 data collections. Preschool physical aggression proved an important longitudinal predictor of adolescent disclosure and concealment for girls. Concurrently, self-rated relational aggression was also significantly associated with concealment for both boys and girls. PMID:23720152

  19. Detection of concealed and buried chemicals by using multifrequency excitations

    SciTech Connect

    Gao Yaohui; Chen, Meng-Ku; Yang, Chia-En; Chang, Yun-Ching; Yao, Jim; Cheng Jiping; Yin, Stuart; Hui Rongqing; Ruffin, Paul; Brantley, Christina; Edwards, Eugene; Luo, Claire

    2010-08-15

    In this paper, we present a new type of concealed and buried chemical detection system by stimulating and enhancing spectroscopic signatures with multifrequency excitations, which includes a low frequency gradient dc electric field, a high frequency microwave field, and higher frequency infrared (IR) radiations. Each excitation frequency plays a unique role. The microwave, which can penetrate into the underground and/or pass through the dielectric covers with low attenuation, could effectively transform its energy into the concealed and buried chemicals and increases its evaporation rate from the sample source. Subsequently, a gradient dc electric field, generated by a Van De Graaff generator, not only serves as a vapor accelerator for efficiently expediting the transportation process of the vapor release from the concealed and buried chemicals but also acts as a vapor concentrator for increasing the chemical concentrations in the detection area, which enables the trace level chemical detection. Finally, the stimulated and enhanced vapors on the surface are detected by the IR spectroscopic fingerprints. Our theoretical and experimental results demonstrate that more than sixfold increase in detection signal can be achieved by using this proposed technology. The proposed technology can also be used for standoff detection of concealed and buried chemicals by adding the remote IR and/or thermal spectroscopic and imaging detection systems.

  20. Quantum Image Steganography and Steganalysis Based On LSQu-Blocks Image Information Concealing Algorithm

    NASA Astrophysics Data System (ADS)

    A. AL-Salhi, Yahya E.; Lu, Songfeng

    2016-04-01

    Quantum steganography can solve some problems that are considered inefficient in image information concealing. It researches on Quantum image information concealing to have been widely exploited in recent years. Quantum image information concealing can be categorized into quantum image digital blocking, quantum image stereography, anonymity and other branches. Least significant bit (LSB) information concealing plays vital roles in the classical world because many image information concealing algorithms are designed based on it. Firstly, based on the novel enhanced quantum representation (NEQR), image uniform blocks clustering around the concrete the least significant Qu-block (LSQB) information concealing algorithm for quantum image steganography is presented. Secondly, a clustering algorithm is proposed to optimize the concealment of important data. Finally, we used Con-Steg algorithm to conceal the clustered image blocks. Information concealing located on the Fourier domain of an image can achieve the security of image information, thus we further discuss the Fourier domain LSQu-block information concealing algorithm for quantum image based on Quantum Fourier Transforms. In our algorithms, the corresponding unitary Transformations are designed to realize the aim of concealing the secret information to the least significant Qu-block representing color of the quantum cover image. Finally, the procedures of extracting the secret information are illustrated. Quantum image LSQu-block image information concealing algorithm can be applied in many fields according to different needs.

  1. Campaign for Right to Carry Concealed Guns on Campuses Gains Traction

    ERIC Educational Resources Information Center

    Wiseman, Rachel

    2012-01-01

    Five years after the Virginia Tech massacre prompted a student in Texas to start a Facebook page in favor of the right to carry concealed weapons on college campuses, the resulting group, Students for Concealed Carry, has advanced its cause. In more than a dozen states, legislation has been introduced to allow the carrying of concealed firearms on…

  2. Quantum Image Steganography and Steganalysis Based On LSQu-Blocks Image Information Concealing Algorithm

    NASA Astrophysics Data System (ADS)

    A. AL-Salhi, Yahya E.; Lu, Songfeng

    2016-08-01

    Quantum steganography can solve some problems that are considered inefficient in image information concealing. It researches on Quantum image information concealing to have been widely exploited in recent years. Quantum image information concealing can be categorized into quantum image digital blocking, quantum image stereography, anonymity and other branches. Least significant bit (LSB) information concealing plays vital roles in the classical world because many image information concealing algorithms are designed based on it. Firstly, based on the novel enhanced quantum representation (NEQR), image uniform blocks clustering around the concrete the least significant Qu-block (LSQB) information concealing algorithm for quantum image steganography is presented. Secondly, a clustering algorithm is proposed to optimize the concealment of important data. Finally, we used Con-Steg algorithm to conceal the clustered image blocks. Information concealing located on the Fourier domain of an image can achieve the security of image information, thus we further discuss the Fourier domain LSQu-block information concealing algorithm for quantum image based on Quantum Fourier Transforms. In our algorithms, the corresponding unitary Transformations are designed to realize the aim of concealing the secret information to the least significant Qu-block representing color of the quantum cover image. Finally, the procedures of extracting the secret information are illustrated. Quantum image LSQu-block image information concealing algorithm can be applied in many fields according to different needs.

  3. Evaluation of spatial resolution and estimation error of seafloor displacement observation from vessel-based bathymetric survey by use of AUV-based bathymetric data

    NASA Astrophysics Data System (ADS)

    Fujiwara, Toshiya; Masaki, Yuka; Yamamoto, Fujio

    2015-03-01

    A repeated bathymetric survey reveals seafloor displacement between before and after geodynamic events. We evaluated the less-known spatial resolution and estimation error of the seafloor displacement observation from a vessel-based multi-narrow beam bathymetric survey. In this evaluation, bathymetric data from vessel-based and near-seafloor high-resolution autonomous underwater vehicle (AUV)-based surveys in the same area were used. Simulated vessel-based bathymetric "before and after" data of the seafloor displacement were made using AUV-based bathymetric data. The displacement was verified by comparing these simulated data using the analysis conditions that no locational errors of beam sounding points exist, a footprint effect is uniform, depth accuracy is constant in the analysis area, and there are no depth offset between two data. As a result, we found that the smallest vertical seafloor displacement that can be detected occurs when the horizontal extent of the deformation is larger than several times the size of the footprint (area of the narrow sounding beam projected onto the seafloor) of the used vessel's multi-narrow beam echo sounder, and in the situation that the amplitude of the depth difference is greater than the accuracy of the vessel-based depth measurement (standard deviation of measuring error). When local slopes of the bathymetry are gentler than those of the artificial variation appeared in the depth differences between two data, the horizontal seafloor displacement seems to be difficult to resolve accurately. The local slope of the artificial depth variation is derived from the wavelength and the amplitude which are equivalent to ~1-3 times of the footprint size and the accuracy of the depth measurement, respectively.

  4. Error-resilient method for robust video transmissions

    NASA Astrophysics Data System (ADS)

    Choi, Dong-Hwan; Lim, Tae-Gyun; Lee, Sang-Hak; Hwang, Chan-Sik

    2003-06-01

    In this paper we address the problems of video transmission in error prone environments. A novel error-resilient method is proposed that uses a data embedding scheme for header parameters in video coding standards, such as MPEG-2 and H.263. In case of requiring taking the loss of data information into account except for header errors, the video decoder hides visual degradation as well as possible, employing an error concealment method using an affine transform. Header information is very important because syntax elements, tables, and decoding processes all depend on the values of the header information. Therefore, transmission errors in header information can result in serious visual degradation of the output video and also cause an abnormal decoding process. In the proposed method, the header parameters are embedded into the least significant bits (LSB) of the quantized DCT coefficients. Then, when errors occur in the header field of the compressed bitstream, the decoder can accurately recover the corrupted header parameters if the embedded information is extracted correctly. The error concealment technique employed in this paper uses motion estimation considering actual motions, such as rotation, magnification, reduction, and parallel motion, in moving pictures. Experimental results show that the proposed error-resilient method can effectively reconstruct the original video sequence without any additional bits or modifications to the video coding standard and the error concealment method can produce a higher PSNR value and better subjective video quality, estimating the motion of lost data more accurately.

  5. Noise-resistant system of concealed information transfer on a chaotic delayed feedback oscillator with switchable delay time

    NASA Astrophysics Data System (ADS)

    Kul'minskii, D. D.; Ponomarenko, V. I.; Karavaev, A. S.; Prokhorov, M. D.

    2016-05-01

    We propose a system of concealed information transfer based on a delayed feedback oscillator with switchable chaotic regimes. The proposed system is analyzed numerically and experimentally. The dependences of the bit error rate during transmission of a binary information signal on the signal-to-noise ratio, attenuation of the signal in the communication channel, and the duration of the time interval during which a bit is transferred are constructed. The high stability of the system to noise and amplitude distortions of a signal in the communication channel is demonstrated.

  6. ID-Check: Online Concealed Information Test Reveals True Identity.

    PubMed

    Verschuere, Bruno; Kleinberg, Bennett

    2016-01-01

    The Internet has already changed people's lives considerably and is likely to drastically change forensic research. We developed a web-based test to reveal concealed autobiographical information. Initial studies identified a number of conditions that affect diagnostic efficiency. By combining these moderators, this study investigated the full potential of the online ID-check. Participants (n = 101) tried to hide their identity and claimed a false identity in a reaction time-based Concealed Information Test. Half of the participants were presented with personal details (e.g., first name, last name, birthday), whereas the others only saw irrelevant details. Results showed that participants' true identity could be detected with high accuracy (AUC = 0.98; overall accuracy: 86-94%). Online memory detection can reliably and validly detect whether someone is hiding their true identity. This suggests that online memory detection might become a valuable tool for forensic applications. PMID:26390033

  7. Could plate tectonics on Venus be concealed by volcanic deposits

    NASA Technical Reports Server (NTRS)

    Kaula, W. M.; Muradian, L. M.

    1982-01-01

    The present investigation is supplementary to a study reported by Kaula and Phillips (1981). From an analysis of Pioneer Venus altimetry, Kaula and Phillips had inferred that any heat loss from the planet by plate tectonics must be small compared to that from the earth. However, it has been suggested by others that plate tectonic may exist on Venus, but that the expected 'square root of s' dependence of the topographic drop off is not observed because it is concealed by lava flows. The present investigation has the objective to conduct an examination whether this suggestion of concealment by lava flow is correct. On the basis of the performed analysis, it is concluded that the results obtained by Kaula and Phillips appear to be well justified.

  8. Biomedical psychiatry and its concealed metaphors: an anthropological perspective.

    PubMed

    Martínez-Hernáez, Angel

    2013-09-01

    The idea that power relations structure social life is self-evident to most anthropologists. Western medical knowledge or biomedicine, and by extension science or scientific knowledge, however, has until relatively recently been exempt from anthropological scrutiny in political terms. An understanding of biomedicine as a system of knowledge that is not a copy of facts but a representation of them has entailed a break with the traditional separation of folk knowledge and scientific knowledge in anthropology, making it possible to include biomedicine in the repertoire of ethnographic objects. The peculiarity of biomedicine as a cultural system, seen from this perspective, lies in a paradox: its self-characterization as a set of non-ideological discourses and practices is a representation that conceals its ideological and power-saturated nature. Through an analysis of DSM-IV-TR, this article explores some of the representational strategies through which this concealment takes place in biomedical psychiatry: the asocial and universal character of mental illness categories; the neutrality of clinical practice; and the non-moral nature of clinical criteria and judgment. These are concealed metaphors in the true sense, for not only do they speak of something without naming it but they also deny their own existence as metaphors. PMID:24308254

  9. Temporal spying and concealing process in fibre-optic data transmission systems through polarization bypass

    PubMed Central

    Bony, P.Y.; Guasoni, M.; Morin, P.; Sugny, D.; Picozzi, A.; Jauslin, H.R.; Pitois, S.; Fatome, J.

    2014-01-01

    Recent research has been focused on the ability to manipulate a light beam in such a way to hide, namely to cloak, an event over a finite time or localization in space. The main idea is to create a hole or a gap in the spatial or time domain so as to allow for an object or data to be kept hidden for a while and then to be restored. By enlarging the field of applications of this concept to telecommunications, researchers have recently reported the possibility to hide transmitted data in an optical fibre. Here we report the first experimental demonstration of perpetual temporal spying and blinding process of optical data in fibre-optic transmission line based on polarization bypass. We successfully characterize the performance of our system by alternatively copying and then concealing 100% of a 10-Gb s−1 transmitted signal. PMID:25135759

  10. Deep Raman spectroscopy for the non-invasive standoff detection of concealed chemical threat agents.

    PubMed

    Izake, Emad L; Cletus, Biju; Olds, William; Sundarajoo, Shankaran; Fredericks, Peter M; Jaatinen, Esa

    2012-05-30

    Deep Raman spectroscopy has been utilized for the standoff detection of concealed chemical threat agents from a distance of 15 m under real life background illumination conditions. By using combined time and space resolved measurements, various explosive precursors hidden in opaque plastic containers were identified non-invasively. Our results confirm that combined time and space resolved Raman spectroscopy leads to higher selectivity towards the sub-layer over the surface layer as well as enhanced rejection of fluorescence from the container surface when compared to standoff spatially offset Raman spectroscopy. Raman spectra that have minimal interference from the packaging material and good signal-to-noise ratio were acquired within 5 s of measurement time. A new combined time and space resolved Raman spectrometer has been designed with nanosecond laser excitation and gated detection, making it of lower cost and complexity than picosecond-based laboratory systems. PMID:22608458

  11. [Effects of false memories on the Concealed Information Test].

    PubMed

    Zaitsu, Wataru

    2012-10-01

    The effects of false memories on polygraph examinations with the Concealed Information Test (CIT) were investigated by using the Deese-Roediger-McDermott (DRM) paradigm, which allows participants to evoke false memories. Physiological responses to questions consisting of learned, lure, and unlearned items were measured and recorded. The results indicated that responses to lure questions showed critical responses to questions about learned items. These responses included repression of respiration, an increase in electrodermal activity, and a drop in heart rate. These results suggest that critical response patterns are generated in the peripheral nervous system by true and false memories. PMID:23214081

  12. Active millimeter wave detection of concealed layers of dielectric material

    NASA Astrophysics Data System (ADS)

    Bowring, N. J.; Baker, J. G.; Rezgui, N. D.; Southgate, M.; Alder, J. F.

    2007-04-01

    Extensive work has been published on millimetre wave active and passive detection and imaging of metallic objects concealed under clothing. We propose and demonstrate a technique for revealing the depth as well as the outline of partially transparent objects, which is especially suited to imaging layer materials such as explosives and drugs. The technique uses a focussed and scanned FMCW source, swept through many GHz to reveal this structure. The principle involved is that a parallel sided dielectric slab produces reflections at both its upper and lower surfaces, acting as a Fabry-Perot interferometer. This produces a pattern of alternating reflected peaks and troughs in frequency space. Fourier or Burg transforming this pattern into z-space generates a peak at the thickness of the irradiated sample. It could be argued that though such a technique may work for single uniform slabs of dielectric material, it will give results of little or no significance when the sample both scatters the incident radiation and gives erratic reflectivities due to its non-uniform thickness and permittivity . We show results for a variety of materials such as explosive simulants, powder and drugs, both alone and concealed under clothing or in a rucksack, which display strongly directional reflectivities at millimeter wavelengths, and whose location is well displayed by a varying thickness parameter as the millimetre beam is scanned across the target. With this system we find that samples can easily be detected at standoff distances of at least 4.6m.

  13. Terahertz imaging system performance model for concealed weapon identification

    NASA Astrophysics Data System (ADS)

    Murrill, Steven R.; Jacobs, Eddie L.; Moyer, Steven K.; Halford, Carl E.; Griffin, Steven T.; De Lucia, Frank C.; Petkie, Douglas T.; Franck, Charmaine C.

    2005-11-01

    The U.S. Army Night Vision and Electronic Sensors Directorate and the U.S. Army Research Laboratory have developed a terahertz-band imaging system performance model for detection and identification of concealed weaponry. The MATLAB-based model accounts for the effects of all critical sensor and display components, and for the effects of atmospheric attenuation, concealment material attenuation, and active illumination. The model is based on recent U.S. Army NVESD sensor performance models that couple system design parameters to observer-sensor field performance using the acquire methodology for weapon identification performance predictions. This THz model has been developed in support of the Defense Advanced Research Project Agencies' Terahertz Imaging Focal-Plane-Array Technology (TIFT) program and is presently being used to guide the design and development of a 0.650 THz active/passive imaging system. This paper will describe the THz model in detail, provide and discuss initial modeling results for a prototype THz imaging system, and outline plans to validate and calibrate the model through human perception testing.

  14. Passive millimeter-wave imaging for concealed article detection

    NASA Astrophysics Data System (ADS)

    Lovberg, John A.; Galliano, Joseph A., Jr.; Clark, Stuart E.

    1997-02-01

    Passive-millimeter-wave imaging (PMI) provides a powerful sensing tool for law enforcement, allowing an unobtrusive means for detecting concealed weapons, explosives, or contraband on persons or in baggage. Natural thermal emissions at millimeter wavelengths from bodies, guns, explosives, and other articles pass easily through clothing or other concealment materials, where they can be detected and converted into conventional 2-dimensional images. A new implementation of PMI has demonstrated a large-area, near- real-time staring capability for personnel inspection at standoff ranges of greater than 10 meters. In this form, PMI does not require operator cuing based on subjective 'profiles' of suspicious appearance or behaviors, which may otherwise be construed as violations of civil rights. To the contrary, PMI detects and images heat generated by any object with no predisposition as to its nature or function (e.g. race or gender of humans). As a totally passive imaging tool, it generates no radio-frequency or other radiation which might raise public health concerns. Specifics of the new PMI architecture are presented along with a host of imaging data representing the current state- of-the-art.

  15. Advanced terahertz imaging system performance model for concealed weapon identification

    NASA Astrophysics Data System (ADS)

    Murrill, Steven R.; Redman, Brian; Espinola, Richard L.; Franck, Charmaine C.; Petkie, Douglas T.; De Lucia, Frank C.; Jacobs, Eddie L.; Griffin, Steven T.; Halford, Carl E.; Reynolds, Joe

    2007-04-01

    The U.S. Army Night Vision and Electronic Sensors Directorate (NVESD) and the U.S. Army Research Laboratory (ARL) have developed a terahertz-band imaging system performance model for detection and identification of concealed weaponry. The details of this MATLAB-based model which accounts for the effects of all critical sensor and display components, and for the effects of atmospheric attenuation, concealment material attenuation, and active illumination, were reported on at the 2005 SPIE Europe Security and Defence Symposium. The focus of this paper is to report on recent advances to the base model which have been designed to more realistically account for the dramatic impact that target and background orientation can have on target observability as related to specular and Lambertian reflections captured by an active-illumination-based imaging system. The advanced terahertz-band imaging system performance model now also accounts for target and background thermal emission, and has been recast into a user-friendly, Windows-executable tool. This advanced THz model has been developed in support of the Defense Advanced Research Project Agency's (DARPA) Terahertz Imaging Focal-Plane Technology (TIFT) program. This paper will describe the advanced THz model and its new radiometric sub-model in detail, and provide modeling and experimental results on target observability as a function of target and background orientation.

  16. Terahertz imaging system performance model for concealed-weapon identification

    NASA Astrophysics Data System (ADS)

    Murrill, Steven R.; Jacobs, Eddie L.; Moyer, Steven K.; Halford, Carl E.; Griffin, Steven T.; De Lucia, Frank C.; Petkie, Douglas T.; Franck, Charmaine C.

    2008-03-01

    The U.S. Army Night Vision and Electronic Sensors Directorate (NVESD) and the U.S. Army Research Laboratory have developed a terahertz (THz) -band imaging system performance model for detection and identification of concealed weaponry. The MATLAB-based model accounts for the effects of all critical sensor and display components and for the effects of atmospheric attenuation, concealment material attenuation, and active illumination. The model is based on recent U.S. Army NVESD sensor performance modeling technology that couples system design parameters to observer-sensor field performance by using the acquire methodology for weapon identification performance predictions. This THz model has been developed in support of the Defense Advanced Research Project Agencies' Terahertz Imaging Focal-Plane Technology (TIFT) program and is currently being used to guide the design and development of a 0.650 THz active-passive imaging system. This paper will describe the THz model in detail, provide and discuss initial modeling results for a prototype THz imaging system, and outline plans to calibrate and validate the model through human perception testing.

  17. Terahertz imaging system performance model for concealed-weapon identification.

    PubMed

    Murrill, Steven R; Jacobs, Eddie L; Moyer, Steven K; Halford, Carl E; Griffin, Steven T; De Lucia, Frank C; Petkie, Douglas T; Franck, Charmaine C

    2008-03-20

    The U.S. Army Night Vision and Electronic Sensors Directorate (NVESD) and the U.S. Army Research Laboratory have developed a terahertz (THz) -band imaging system performance model for detection and identification of concealed weaponry. The MATLAB-based model accounts for the effects of all critical sensor and display components and for the effects of atmospheric attenuation, concealment material attenuation, and active illumination. The model is based on recent U.S. Army NVESD sensor performance modeling technology that couples system design parameters to observer-sensor field performance by using the acquire methodology for weapon identification performance predictions. This THz model has been developed in support of the Defense Advanced Research Project Agencies' Terahertz Imaging Focal-Plane Technology (TIFT) program and is currently being used to guide the design and development of a 0.650 THz active-passive imaging system. This paper will describe the THz model in detail, provide and discuss initial modeling results for a prototype THz imaging system, and outline plans to calibrate and validate the model through human perception testing. PMID:18709076

  18. Separating deceptive and orienting components in a Concealed Information Test.

    PubMed

    Ambach, Wolfgang; Stark, Rudolf; Peper, Martin; Vaitl, Dieter

    2008-11-01

    The Concealed Information Test (CIT) requires the examinee to deceptively deny recognition of known stimuli and to truthfully deny recognition of unknown stimuli. Because deception and orienting are typically coupled, it is unclear how exactly these sub-processes affect the physiological responses measured in the CIT. The present study aimed at separating the effects of deception from those of orienting. In a mock-crime study, using a modified CIT, thirty-six of seventy-two subjects answered truthfully ('truth group'), whereas the other thirty-six concealed their knowledge ('lie group'). Answering was delayed for 4 s after item presentation. Electrodermal activity (EDA), respiration (RLL), and phasic heart rate (HR) were recorded. A decomposition of EDA responses revealed two response components; the response in the first interval was expected to indicate orienting, stimulus evaluation, and answer preparation, whereas the response in the second interval was assumed to reflect answer-related processes. Inconclusively, both EDA components differentiated between 'probe' and 'irrelevant' items in both groups. Phasic HR and RLL differed between item classes only in the 'lie' group, thus reflecting answer-related processes, possibly deception, rather than merely orienting responses. The findings further support the notion that psychophysiological measures elicited by a modified CIT may reflect different mental processes involved in orienting and deception. PMID:18674573

  19. Skin conductance as an indicator of anticipated concealed knowledge.

    PubMed

    Hu, Senqi; Huang, Hsin-Yu; McGovern, Jamie L; Jacobs, David A

    2008-06-01

    The present study investigated the effects of anticipation on skin conductance while participants were answering a set of questions which included one of concealed knowledge. Two experiments were conducted. In Exp. 1, 26 participants completed one experimental session. Each participant was asked to choose one two-digit number from 10 to 99 and was presented 19 other randomly generated two-digit numbers. The list of numbers was then presented to the participant on a computer screen, with a 60-sec. interval occurring every two questions. The participant-selected number was defined as the target question which was randomly placed within the 4th to 17th item of 20 questions stated as follows: "Is your selected number?" The participant was asked to answer "No" to all questions. The skin-conductance response to each question was measured. In Exp. 2, the experimental procedure was the same as that in Exp. 1 except each participant first answered 10 nontarget questions, then answered a target question with the participant's selected number, and then answered another 10 nontarget questions. There were a total of 21 questions. Analysis indicated participants in both experiments generated the highest mean skin conductance while answering the target questions, followed by lower amplitudes to questions prior to and after the target question. The skin-conductance response pattern can be used to identify the psychological process of anticipation of concealed information. PMID:18763466

  20. Target Speaker Detection with Concealed EEG Around the Ear

    PubMed Central

    Mirkovic, Bojana; Bleichner, Martin G.; De Vos, Maarten; Debener, Stefan

    2016-01-01

    Target speaker identification is essential for speech enhancement algorithms in assistive devices aimed toward helping the hearing impaired. Several recent studies have reported that target speaker identification is possible through electroencephalography (EEG) recordings. If the EEG system could be reduced to acceptable size while retaining the signal quality, hearing aids could benefit from the integration with concealed EEG. To compare the performance of a multichannel around-the-ear EEG system with high-density cap EEG recordings an envelope tracking algorithm was applied in a competitive speaker paradigm. The data from 20 normal hearing listeners were concurrently collected from the traditional state-of-the-art laboratory wired EEG system and a wireless mobile EEG system with two bilaterally-placed around-the-ear electrode arrays (cEEGrids). The results show that the cEEGrid ear-EEG technology captured neural signals that allowed the identification of the attended speaker above chance-level, with 69.3% accuracy, while cap-EEG signals resulted in the accuracy of 84.8%. Further analyses investigated the influence of ear-EEG signal quality and revealed that the envelope tracking procedure was unaffected by variability in channel impedances. We conclude that the quality of concealed ear-EEG recordings as acquired with the cEEGrid array has potential to be used in the brain-computer interface steering of hearing aids. PMID:27512364

  1. Pulsed neutron interrogation for detection of concealed special nuclear materials

    NASA Astrophysics Data System (ADS)

    Ruddy, Frank; Seidel, John; Flammang, Robert; Petrović, Bojan; Dulloo, Abdul; Congedo, Thomas

    2006-05-01

    A new neutron interrogation technique for detection of concealed Special Nuclear Material (SNM) is described. This technique is a combination of timing techniques from pulsed prompt gamma neutron activation analysis with silicon carbide (SiC) semiconductor fast neutron detector technology. SiC detectors are a new class of radiation detectors that are ultra-fast and capable of processing high count rates. SiC detectors can operate during and within nanoseconds of the end of an intense neutron pulse, providing the ability to detect the prompt neutron emissions from fission events produced by the neutrons in concealed SNM on a much faster pulsing time scale than has been achieved by other techniques. Neutron-induced fission neutrons in 235U have been observed in the time intervals between pulses of 14-MeV neutrons from a deuterium-tritium electronic neutron generator. Initial measurements have emphasized the detection of SNM using thermal-neutron induced fission. Neutron pulsing and time-sequenced neutron counts were carried out on a hundreds of microseconds time scale, enabling the observation of prompt fission neutrons induced by the die-away of thermal neutrons following the 14-MeV pulse. A discussion of pulsed prompt-neutron measurements and of SiC detectors as well as initial measurement results will be presented.

  2. 3D laser imaging for concealed object identification

    NASA Astrophysics Data System (ADS)

    Berechet, Ion; Berginc, Gérard; Berechet, Stefan

    2014-09-01

    This paper deals with new optical non-conventional 3D laser imaging. Optical non-conventional imaging explores the advantages of laser imaging to form a three-dimensional image of the scene. 3D laser imaging can be used for threedimensional medical imaging, topography, surveillance, robotic vision because of ability to detect and recognize objects. In this paper, we present a 3D laser imaging for concealed object identification. The objective of this new 3D laser imaging is to provide the user a complete 3D reconstruction of the concealed object from available 2D data limited in number and with low representativeness. The 2D laser data used in this paper come from simulations that are based on the calculation of the laser interactions with the different interfaces of the scene of interest and from experimental results. We show the global 3D reconstruction procedures capable to separate objects from foliage and reconstruct a threedimensional image of the considered object. In this paper, we present examples of reconstruction and completion of three-dimensional images and we analyse the different parameters of the identification process such as resolution, the scenario of camouflage, noise impact and lacunarity degree.

  3. Target Speaker Detection with Concealed EEG Around the Ear.

    PubMed

    Mirkovic, Bojana; Bleichner, Martin G; De Vos, Maarten; Debener, Stefan

    2016-01-01

    Target speaker identification is essential for speech enhancement algorithms in assistive devices aimed toward helping the hearing impaired. Several recent studies have reported that target speaker identification is possible through electroencephalography (EEG) recordings. If the EEG system could be reduced to acceptable size while retaining the signal quality, hearing aids could benefit from the integration with concealed EEG. To compare the performance of a multichannel around-the-ear EEG system with high-density cap EEG recordings an envelope tracking algorithm was applied in a competitive speaker paradigm. The data from 20 normal hearing listeners were concurrently collected from the traditional state-of-the-art laboratory wired EEG system and a wireless mobile EEG system with two bilaterally-placed around-the-ear electrode arrays (cEEGrids). The results show that the cEEGrid ear-EEG technology captured neural signals that allowed the identification of the attended speaker above chance-level, with 69.3% accuracy, while cap-EEG signals resulted in the accuracy of 84.8%. Further analyses investigated the influence of ear-EEG signal quality and revealed that the envelope tracking procedure was unaffected by variability in channel impedances. We conclude that the quality of concealed ear-EEG recordings as acquired with the cEEGrid array has potential to be used in the brain-computer interface steering of hearing aids. PMID:27512364

  4. Concealed Threat Detection at Multiple Frames-per-second

    SciTech Connect

    Chang, J T

    2005-11-08

    In this LDRD project, our research purpose is to investigate the science and technology necessary to enable real-time array imaging as a rapid way to detect hidden threats through obscurants such as smoke, fog, walls, doors, and clothing. The goal of this research is to augment the capabilities of protective forces in concealed threat detection. In the current context, threats include people as well as weapons. In most cases, security personnel must make very fast assessments of a threat based upon limited amount of data. Among other attributes, UWB has been shown and quantified to penetrate and propagate through many materials (wood, some concretes, non-metallic building materials, some soils, etc.) while maintaining high range resolution. We have build collaborations with university partners and government agencies. We have considered the impact of psychometrics on target recognition and identification. Specifically we have formulated images in real-time that will engage the user's vision system in a more active way to enhance image interpretation capabilities. In this project, we are researching the use of real time (field programmable gate arrays) integrated with high resolution (cm scale), ultra wide band (UWB) electromagnetic signals for imaging personnel through smoke and walls. We evaluated the ability of real-time UWB imaging for detecting smaller objects, such as concealed weapons that are carried by the obscured personnel. We also examined the cognitive interpretation process of real time UWB electromagnetic images.

  5. When Concealed Handgun Licensees Break Bad: Criminal Convictions of Concealed Handgun Licensees in Texas, 2001–2009

    PubMed Central

    Nwaiwu, Obioma; McMaughan Moudouni, Darcy K.; Edwards, Rachel; Lin, Szu-hsuan

    2013-01-01

    Objectives. We explored differences in criminal convictions between holders and nonholders of a concealed handgun license (CHL) in Texas. Methods. The Texas Department of Public Safety (DPS) provides annual data on criminal convictions of holders and nonholders of CHLs. We used 2001 to 2009 DPS data to investigate the differences in the distribution of convictions for these 2 groups across 9 types of criminal offenses. We calculated z scores for the differences in the types of crimes for which CHL holders and nonholders were convicted. Results. CHL holders were much less likely than nonlicensees to be convicted of crimes. Most nonholder convictions involved higher-prevalence crimes (burglary, robbery, or simple assault). CHL holders’ convictions were more likely to involve lower-prevalence crimes, such as sexual offenses, gun offenses, or offenses involving a death. Conclusions. Our results imply that expanding the settings in which concealed carry is permitted may increase the risk of specific types of crimes, some quite serious in those settings. These increased risks may be relatively small. Nonetheless, policymakers should consider these risks when contemplating reducing the scope of gun-free zones. PMID:23153139

  6. 27 CFR 447.62 - False statements or concealment of facts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... concealment of facts. 447.62 Section 447.62 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO... IMPLEMENTS OF WAR Penalties, Seizures and Forfeitures § 447.62 False statements or concealment of facts. Any... fact or fails to state a material fact required to be stated therein or necessary to make...

  7. 27 CFR 447.62 - False statements or concealment of facts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... concealment of facts. 447.62 Section 447.62 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO... IMPLEMENTS OF WAR Penalties, Seizures and Forfeitures § 447.62 False statements or concealment of facts. Any... fact or fails to state a material fact required to be stated therein or necessary to make...

  8. 27 CFR 447.62 - False statements or concealment of facts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... concealment of facts. 447.62 Section 447.62 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO... IMPLEMENTS OF WAR Penalties, Seizures and Forfeitures § 447.62 False statements or concealment of facts. Any... fact or fails to state a material fact required to be stated therein or necessary to make...

  9. 27 CFR 447.62 - False statements or concealment of facts.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... concealment of facts. 447.62 Section 447.62 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO... IMPLEMENTS OF WAR Penalties, Seizures and Forfeitures § 447.62 False statements or concealment of facts. Any... fact or fails to state a material fact required to be stated therein or necessary to make...

  10. 27 CFR 447.62 - False statements or concealment of facts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... concealment of facts. 447.62 Section 447.62 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO... IMPLEMENTS OF WAR Penalties, Seizures and Forfeitures § 447.62 False statements or concealment of facts. Any... fact or fails to state a material fact required to be stated therein or necessary to make...

  11. Error robustness evaluation of H.264/MPEG-4 AVC

    NASA Astrophysics Data System (ADS)

    Halbach, Till; Olsen, Steffen

    2004-01-01

    The robustness of the recently ratified video compression standard H.264/MPEG-4 AVC against channel errors is evaluated with the focus on rate distortion matters. After a brief introduction of the standard and an explanation of its error-resistant features, it is investigated how the error resilience tools of H.264 can be deployed best for packet-wise transmission as in ATM, H.323, and IP-based services. Further, the performances of two error concealment strategies for use in an H.264-conform decoder are compared to each other.

  12. Regulatory focus moderates the social performance of individuals who conceal a stigmatized identity.

    PubMed

    Newheiser, Anna-Kaisa; Barreto, Manuela; Ellemers, Naomi; Derks, Belle; Scheepers, Daan

    2015-12-01

    People often choose to hide a stigmatized identity to avoid bias. However, hiding stigma can disrupt social interactions. We considered whether regulatory focus qualifies the social effects of hiding stigma by examining interactions in which stigmatized participants concealed a devalued identity from non-stigmatized partners. In the Prevention Focus condition, stigmatized participants were instructed to prevent a negative impression by concealing the identity; in the Promotion Focus condition, they were instructed to promote a positive impression by concealing the identity; in the Control condition, they were simply asked to conceal the identity. Both non-stigmatized partners and independent raters rated the interactions more positively in the Promotion Focus condition. Thus, promotion focus is interpersonally beneficial for individuals who conceal a devalued identity. PMID:25780853

  13. Multi-channel millimeter wave image registration and segmentation for concealed object detection

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Su; Yeom, Seokwon; Son, Jung-Young; Kim, Shin-Hwan

    2010-04-01

    We address an image registration and segmentation method to detect concealed objects captured by passive millimeter wave (MMW) imaging. Passive MMW imaging can create interpretable imagery on the objects concealed under clothing. Due to the penetrating property of the MMW imaging, the MMW imaging system is often employed for the security and defense system. In this paper, we utilize a multi-channel PMMW imaging system operating at the 8 mm regime with linear polarization. Image registration and segmentation are performed to detect concealed objects under clothing. The registration is preceded to align different channel images by means of geometric feature extraction and a matching process. The Linde-Buzo-Gray (LBG) vector quantization with multi-channel information is adopted to segment the concealed object from the body area. In the experiment, the automated image registration and segmentation are performed with various concealed objects including a metal axe and a liquid container.

  14. Selection of food patches by sympatric herbivores in response to concealment and distance from a refuge.

    PubMed

    Crowell, Miranda M; Shipley, Lisa A; Camp, Meghan J; Rachlow, Janet L; Forbey, Jennifer S; Johnson, Timothy R

    2016-05-01

    Small herbivores face risks of predation while foraging and are often forced to trade off food quality for safety. Life history, behaviour, and habitat of predator and prey can influence these trade-offs. We compared how two sympatric rabbits (pygmy rabbit, Brachylagus idahoensis; mountain cottontail, Sylvilagus nuttallii) that differ in size, use of burrows, and habitat specialization in the sagebrush-steppe of western North America respond to amount and orientation of concealment cover and proximity to burrow refuges when selecting food patches. We predicted that both rabbit species would prefer food patches that offered greater concealment and food patches that were closer to burrow refuges. However, because pygmy rabbits are small, obligate burrowers that are restricted to sagebrush habitats, we predicted that they would show stronger preferences for greater cover, orientation of concealment, and patches closer to burrow refuges. We offered two food patches to individuals of each species during three experiments that either varied in the amount of concealment cover, orientation of concealment cover, or distance from a burrow refuge. Both species preferred food patches that offered greater concealment, but pygmy rabbits generally preferred terrestrial and mountain cottontails preferred aerial concealment. Only pygmy rabbits preferred food patches closer to their burrow refuge. Different responses to concealment and proximity to burrow refuges by the two species likely reflect differences in perceived predation risks. Because terrestrial predators are able to dig for prey in burrows, animals like pygmy rabbits that rely on burrow refuges might select food patches based more on terrestrial concealment. In contrast, larger habitat generalists that do not rely on burrow refuges, like mountain cottontails, might trade off terrestrial concealment for visibility to detect approaching terrestrial predators. This study suggests that body size and evolutionary adaptations

  15. Temperature effects on polygraph detection of concealed information.

    PubMed

    MacNeill, A Luke; Bradley, M T

    2016-02-01

    Thermoregulatory influences on electrodermal and cardiovascular activity may interfere with the detection of concealed information using a polygraph. This possibility was assessed by means of a mock terrorism scenario. Seventy-two participants were assigned to either a guilty or an innocent role. They were given a polygraph test at one of three ambient temperatures: 10°C, 22°C, or 34°C. Among guilty participants, electrodermal and cardiovascular measures were least effective at 10°C. Electrodermal results were optimal at 22°C, whereas cardiovascular results were optimal at 34°C. Among innocent participants, the effectiveness of these same measures was not affected by ambient temperature. Temperature had no significant impact on respiration results within the guilty or the innocent groups. Taken together, these findings have implications for those who use polygraphs in uncontrolled testing environments. PMID:26435532

  16. Incidental radiographic finding of the concealed art of susuk.

    PubMed

    Devang Divakar, Darshan; Mavinapalla, Seema; Al Kheraif, Abdulaziz Abdullah; Ramakrishnaiah, Ravikumar; Abd Rahim, Muhammad Furqon Bin; Khan, Aftab Ahmed

    2016-07-01

    Susuk, or charm needles, are small, metallic needles inserted under the skin, considered to enhance beauty, health and luck. This hidden secret of inserting susuk is a traditional superstitious ritual, widely practiced among women of Southeast Asia. Here, we present an interesting case of incidental radiographic finding of the concealed art of susuk, which was exposed on a panoramic radiograph taken on a routine basis as a part of diagnostic work up at our centre. An orthopantomogram revealed bilateral metallic foreign bodies in the maxillo-facial region. Anamnestic data affirmed the practice of the body art of susuk. The charm needles were present in the orofacial region without the patient experiencing any pathological signs or symptoms. PMID:26271077

  17. Digital key for chaos communication performing time delay concealment.

    PubMed

    Nguimdo, Romain Modeste; Colet, Pere; Larger, Laurent; Pesquera, Luís

    2011-07-15

    We introduce a scheme that integrates a digital key in a phase-chaos electro-optical delay system for optical chaos communications. A pseudorandom binary sequence (PRBS) is mixed within the chaotic dynamics in a way that a mutual concealment is performed; e.g., the time delay is hidden by the binary sequence, and the PRBS is also masked by the chaos. In addition to bridging the gap between algorithmic symmetric key cryptography and chaos-based analog encoding, the proposed approach is intended to benefit from the complex algebra mixing between a (pseudorandom) Boolean variable, and another continuous time (chaotic) variable. The scheme also provides a large flexibility allowing for easy reconfigurations to communicate securely at a high bit rate between different systems. PMID:21838363

  18. Digital Key for Chaos Communication Performing Time Delay Concealment

    NASA Astrophysics Data System (ADS)

    Nguimdo, Romain Modeste; Colet, Pere; Larger, Laurent; Pesquera, Luís

    2011-07-01

    We introduce a scheme that integrates a digital key in a phase-chaos electro-optical delay system for optical chaos communications. A pseudorandom binary sequence (PRBS) is mixed within the chaotic dynamics in a way that a mutual concealment is performed; e.g., the time delay is hidden by the binary sequence, and the PRBS is also masked by the chaos. In addition to bridging the gap between algorithmic symmetric key cryptography and chaos-based analog encoding, the proposed approach is intended to benefit from the complex algebra mixing between a (pseudorandom) Boolean variable, and another continuous time (chaotic) variable. The scheme also provides a large flexibility allowing for easy reconfigurations to communicate securely at a high bit rate between different systems.

  19. Pathways Between Concealable Stigmatized Identities and Substance Misuse

    PubMed Central

    Talley, Amelia E.; Littlefield, Andrew K.

    2015-01-01

    Individuals with concealable stigmatized identities often possess no obviously devalued attributes, yet are at greater risk for problematic substance use compared to their privileged counterparts. We present a conceptual model, which proposes that identity-relevant content and characteristics have important implications for cognitive, affective, and behavioral consequences of stigma-related stress. In doing so, we synthesize stigma-related models from the extant literature and attempt to integrate these concepts with previous work detailing potential contributors to substance use behaviors specifically. Finally, we ask readers to consider the various ways in which the content and characteristics of an individual’s stigmatized identity might combine with situational and additional individual difference factors to influence the likelihood of substance misuse. PMID:26379766

  20. Microwave-Spectral Signatures Would Reveal Concealed Objects

    NASA Technical Reports Server (NTRS)

    Arndt, G.; Ngo, P.; Carl, J. R.; Byerly, K.; Stolarcyzk, L.

    2004-01-01

    A proposed technique for locating concealed objects (especially small antipersonnel land mines) involves the acquisition and processing of spectral signatures over broad microwave frequency bands. This technique was conceived to overcome the weaknesses of older narrow- band electromagnetic techniques like ground-probing radar and low-frequency electromagnetic induction. Ground-probing radar is susceptible to false detections and/or interference caused by rocks, roots, air pockets, soil inhomogeneities, ice, liquid water, and miscellaneous buried objects other than those sought. Moreover, if the radar frequency happens to be one for which the permittivity of a sought object matches the permittivity of the surrounding soil or there is an unfavorable complex-amplitude addition of the radar reflection at the receiver, then the object is not detected. Low-frequency electromagnetic induction works well for detecting metallic objects, but the amounts of metal in plastic mines are often too small to be detectable. The potential advantage of the proposed technique arises from the fact that wideband spectral signatures generally contain more relevant information than do narrow-band signals. Consequently, spectral signatures could be used to make better decisions regarding whether concealed objects are present and whether they are the ones sought. In some cases, spectral signatures could provide information on the depths, sizes, shapes, and compositions of objects. An apparatus to implement the proposed technique (see Figure 1) could be assembled from equipment already in common use. Typically, such an apparatus would include a radio-frequency (RF) transmitter/receiver, a broad-band microwave antenna, and a fast personal computer loaded with appropriate software. In operation, the counter would be turned on, the antenna would be aimed at the ground or other mass suspected to contain a mine or other sought object, and the operating frequency would be swept over the band of

  1. Refractive Errors

    MedlinePlus

    ... and lens of your eye helps you focus. Refractive errors are vision problems that happen when the ... cornea, or aging of the lens. Four common refractive errors are Myopia, or nearsightedness - clear vision close ...

  2. Theoretical analysis on the measurement errors of local 2D DIC: Part I temporal and spatial uncertainty quantification of displacement measurements

    DOE PAGESBeta

    Wang, Yueqi; Lava, Pascal; Reu, Phillip; Debruyne, Dimitri; Van Houtte, Paul

    2015-12-23

    This study presents a theoretical uncertainty quantification of displacement measurements by subset-based 2D-digital image correlation. A generalized solution to estimate the random error of displacement measurement is presented. The obtained solution suggests that the random error of displacement measurements is determined by the image noise, the summation of the intensity gradient in a subset, the subpixel part of displacement, and the interpolation scheme. The proposed method is validated with virtual digital image correlation tests.

  3. Hypoxia in the St. Lawrence Estuary: How a Coding Error Led to the Belief that “Physics Controls Spatial Patterns”

    PubMed Central

    2015-01-01

    Two fundamental sign errors were found in a computer code used for studying the oxygen minimum zone (OMZ) and hypoxia in the Estuary and Gulf of St. Lawrence. These errors invalidate the conclusions drawn from the model, and call into question a proposed mechanism for generating OMZ that challenges classical understanding. The study in question is being cited frequently, leading the discipline in the wrong direction. PMID:26397371

  4. Decomposition of Concealed and Exposed Porcine Remains in the North Carolina Piedmont.

    PubMed

    Cammack, J A; Cohen, A C; Kreitlow, K L; Roe, R M; Watson, D W

    2016-01-01

    We examined the decomposition and subsequent insect colonization of small pig carrion (Sus scrofa (L.)) placed in concealed and open environments during spring, summer, and fall in Raleigh, North Carolina, as a model for juvenile human remains. Remains were concealed in simulated attics in three manners, ranging from minimal to well-concealed. Concealment had a significant effect on the insect community colonizing the remains across all three seasons; the beetles Necrobia rufipes (DeGeer) (Cleridae) and Dermestes maculatus (DeGeer) (Coleoptera: Dermestidae) were the only species indicative of remains located indoors, whereas numerous fly (Diptera: Calliphoridae, Muscidae, Sepsidae, and Piophilidae) and beetle (Coleoptera: Silphidae, Staphylinidae, and Histeridae) species and an ant species (Hymenoptera: Formicidae, Prenolepis sp.) were indicative of remains located outdoors. Season also significantly affected the insect species, particularly the blow flies (Diptera: Calliphoridae) colonizing remains: Lucilia illustris (Meigen) was indicative of the spring, Cochliomyia macellaria (F.) and Chrysomya megacephala (F.) were indicative of the summer, and Calliphora vicina Robineau-Desvoidy and Calliphora vomitoria (L.) were indicative of the fall. In addition, across all seasons, colonization was delayed by 35–768 h, depending on the degree of concealment. These differences among the insect communities across seasons and concealment treatments, and the effects of concealment on colonization indicate that such information is important and should to be considered when analyzing entomological evidence for criminal investigations. PMID:26590193

  5. A Concealed Barcode Identification System Using Terahertz Time-domain Spectroscopy

    NASA Astrophysics Data System (ADS)

    Guan, Yu; Yamamoto, Manabu; Kitazawa, Toshiyuki; Tripathi, Saroj R.; Takeya, Kei; Kawase, Kodo

    2015-03-01

    We present a concealed terahertz barcode/chipless tag to achieve remote identification through an obstructing material using terahertz radiation. We show scanned terahertz reflection spectral images of barcodes concealed by a thick obstacle. A concealed and double- side printed terahertz barcode structure is proposed, and we demonstrate that our design has better performance in definition than a single-side printed barcode using terahertz time-domain spectroscopy. This technique combines the benefits of a chipless tag to read encoded information covered by an optically opaque material with low cost and a simple fabrication process. Simulations are also described, along with an explanation of the principle of the terahertz barcode identification system.

  6. Tests of a Dynamic Systems Account of the A-not-B Error: The Influence of Prior Experience on the Spatial Memory Abilities of Two-Year-Olds.

    ERIC Educational Resources Information Center

    Spencer, John P.; Smith, Linda B.; Thelen, Esther

    2001-01-01

    Five experiments tested hypothesis that the A-not-B error results from general processes that make goal-directed actions to remembered locations. Findings showed that 2-year-olds' performance on the A trial was accurate. When the object was hidden at Location B, searches after 10-second delay were biased in the direction of Location A. This bias…

  7. Errors on interrupter tasks presented during spatial and verbal working memory performance are linearly linked to large-scale functional network connectivity in high temporal resolution resting state fMRI.

    PubMed

    Magnuson, Matthew Evan; Thompson, Garth John; Schwarb, Hillary; Pan, Wen-Ju; McKinley, Andy; Schumacher, Eric H; Keilholz, Shella Dawn

    2015-12-01

    The brain is organized into networks composed of spatially separated anatomical regions exhibiting coherent functional activity over time. Two of these networks (the default mode network, DMN, and the task positive network, TPN) have been implicated in the performance of a number of cognitive tasks. To directly examine the stable relationship between network connectivity and behavioral performance, high temporal resolution functional magnetic resonance imaging (fMRI) data were collected during the resting state, and behavioral data were collected from 15 subjects on different days, exploring verbal working memory, spatial working memory, and fluid intelligence. Sustained attention performance was also evaluated in a task interleaved between resting state scans. Functional connectivity within and between the DMN and TPN was related to performance on these tasks. Decreased TPN resting state connectivity was found to significantly correlate with fewer errors on an interrupter task presented during a spatial working memory paradigm and decreased DMN/TPN anti-correlation was significantly correlated with fewer errors on an interrupter task presented during a verbal working memory paradigm. A trend for increased DMN resting state connectivity to correlate to measures of fluid intelligence was also observed. These results provide additional evidence of the relationship between resting state networks and behavioral performance, and show that such results can be observed with high temporal resolution fMRI. Because cognitive scores and functional connectivity were collected on nonconsecutive days, these results highlight the stability of functional connectivity/cognitive performance coupling. PMID:25563228

  8. Severe forms of concealed penis without hypospadias: Surgical strategies

    PubMed Central

    de Jesus, Lisieux Eyer; Dekermacher, Samuel; Anderson, Kleber M.

    2015-01-01

    Introduction: Concealed penis (CP) may vary in severity and includes megaprepuce (MP) as a variant. Many different surgical strategies have been described in order to maximize penile exposure and to deal with skin deficiency. We describe the strategies that we use to overcome technical problems in severe cases of CP. Materials and Methods: Six consecutive cases of severe CP (including 3 with MP) were treated in a 2-year period between January 2011 and April 2013. These patients were treated using extensive degloving, removal of dysplastic dartos, Alexander's preputial flap, scrotal flaps and skin grafts. Three patients had been previously circumcised. Cases associated with hypospadias, obesity, disorders of sexual differentiation and micropenises were excluded. Results: All six patients attained good results, with good exposure of the penis, ability to void standing with a well-directed flow and reasonable esthetic results. A technical algorithm for the treatment of primary or recurring cases of CP is proposed. Conclusion: Alexander’ s distally based ventral preputial flap is a useful technical resource to treat MP cases. Free skin grafts and/or laterally based scrotal flaps may be used to cover the penis after release in severe cases of CP. PMID:26604447

  9. Concealed Utility Route Planning: Guidelines for Indian Residential Buildings

    NASA Astrophysics Data System (ADS)

    Gupta, Sumana

    2015-09-01

    Utility lines, particularly in Indian residential buildings, are networked in a haphazard manner to economize and expedite the process of laying conduits. They remain concealed behind the wall finish exposing problems later. The conventional method adopted while laying the routes does not economize the process rather it damages the newly constructed building. After an investigation of the practiced methods through reconnaissance, a construction vocabulary in form of guidelines is recommended for brick residential construction. Taking advantage of the versatility of a brick and considering it as an indigenous construction material of the Indian plains, a judicious way of brick laying can create horizontal and vertical chase at specified heights to receive the utility conduits. The method will simplify, expedite, and organize the utility routes and provide a seamless connection of major utility lines in a residential building. It will aid in future augmentation, easy maintenance, cost reduction and time involved in construction. Practical training of masons and awareness of relevant contractors at site is required through trained site supervisors. The proposed method merits further investigation for inclusion in academic curriculums of the trade.

  10. CW THz scanning transmission imaging for concealed object detection

    NASA Astrophysics Data System (ADS)

    Li, Qi; Yao, Rui; Yin, Qiguo; Ding, Shenghui; Wang, Qi

    2009-07-01

    In the paper, the two-dimensional THz imaging methods are described. The SIFIR-50 FPL Far-Infrared Laser is used as the THz source. The output frequency is 2.5THz in the experiment, because the THz laser operates steadily at this frequency. The P4-42 detector works at room temperature and offers relatively high sensitivity. The software of THz imaging system is self-designed, and it plays a crucial role in this imaging system because it controls nearly all the operations of this system, including the two-dimensional scanning, image data collection, image data storage, image display and image processing. Utilizing this setup, THz transmission images of concealed objects are obtained. In the experiment, a bottle cap and a plastic board covered by reflective materials are chosen as the imaging objects; paper and Teflon are placed before the object to test the transmission imaging effect. The experimental results show that this imaging system can generate clear images.

  11. Countermeasure mechanisms in a P300-based concealed information test.

    PubMed

    Meixner, John B; Rosenfeld, J Peter

    2010-01-01

    We recently introduced an accurate and countermeasure (CM)-resistant P300-based deception detection test (J.P. Rosenfeld et al., 2008). When subjects use CMs to all irrelevant items in the test, the probe P300 is increased rather than reduced, as in previous P300-based deception protocols, allowing detection of CM users. Evidence herein suggests this is partly due to an omit effect; the probe was the only uncountered item. Three groups were tested: a guilty omit probe group performed an explicit response to each irrelevant item but not to the probe, an innocent omit irrelevant group saw only irrelevant items and omitted a response to one item, and a guilty no omit group had a concealed information item as probe and performed an explicit response to each. We found a greater P300 amplitude to probes in the guilty omit probe condition as compared with the other two conditions, indicating a P300 enhancing effect of omitting a response to a single stimulus. PMID:19761523

  12. The neural correlates of identity faking and concealment: an FMRI study.

    PubMed

    Ding, Xiao Pan; Du, Xiaoxia; Lei, Du; Hu, Chao Super; Fu, Genyue; Chen, Guopeng

    2012-01-01

    The neural basis of self and identity has received extensive research. However, most of these existing studies have focused on situations where the internal representation of the self is consistent with the external one. The present study used fMRI methodology to examine the neural correlates of two different types of identity conflict: identity faking and concealment. Participants were presented with a sequence of names and asked to either conceal their own identity or fake another one. The results revealed that the right insular cortex and bilaterally inferior frontal gyrus were more active for identity concealment compared to the control condition, whereas identity faking elicited a significantly larger percentage signal increase than the control condition in the right superior frontal gyrus, left calcarine, and right caudate. These results suggest that different neural systems associated with both identity processing and deception were involved in identity concealment and faking. PMID:23144915

  13. Concealed pregnancy and newborn abandonment: a contemporary 21st century issue. Part 1.

    PubMed

    Tighe, Sylvia Murphy; Lalor, Joan

    2016-06-01

    This two-part series explores the phenomenon of concealed pregnancy and the association with newborn abandonment, with reference to recent cases of public interest. In Part 1 we focus on defining concealed pregnancy as a complex process which involves hiding a pregnancy, that can lead to tragic consequences such as maternal or neonatal morbidity or mortality (Murphy Tighe and Lalor 2016; Chen et al 2007).The psychosocial issues involved will also be presented (Murphy Tighe and Lalor 2016). PMID:27451485

  14. Digital spatial data for observed, predicted, and misclassification errors for observations in the training dataset for nitrate and arsenic concentrations in basin-fill aquifers in the Southwest Principal Aquifers study area

    USGS Publications Warehouse

    McKinney, Tim S.; Anning, David W.

    2012-01-01

    This product "Digital spatial data for observed, predicted, and misclassification errors for observations in the training dataset for nitrate and arsenic concentrations in basin-fill aquifers in the Southwest Principal Aquifers study area" is a 1:250,000-scale point spatial dataset developed as part of a regional Southwest Principal Aquifers (SWPA) study (Anning and others, 2012). The study examined the vulnerability of basin-fill aquifers in the southwestern United States to nitrate contamination and arsenic enrichment. Statistical models were developed by using the random forest classifier algorithm to predict concentrations of nitrate and arsenic across a model grid that represents local- and basin-scale measures of source, aquifer susceptibility, and geochemical conditions.

  15. Impulse radar imaging system for concealed object detection

    NASA Astrophysics Data System (ADS)

    Podd, F. J. W.; David, M.; Iqbal, G.; Hussain, F.; Morris, D.; Osakue, E.; Yeow, Y.; Zahir, S.; Armitage, D. W.; Peyton, A. J.

    2013-10-01

    Electromagnetic systems for imaging concealed objects at checkpoints typically employ radiation at millimetre and terahertz frequencies. These systems have been shown to be effective and provide a sufficiently high resolution image. However there are difficulties and current electromagnetic systems have limitations particularly in accurately differentiating between threat and innocuous objects based on shape, surface emissivity or reflectivity, which are indicative parameters. In addition, water has a high absorption coefficient at millimetre wavelength and terahertz frequencies, which makes it more difficult for these frequencies to image through thick damp clothing. This paper considers the potential of using ultra wideband (UWB) in the low gigahertz range. The application of this frequency band to security screening appears to be a relatively new field. The business case for implementing the UWB system has been made financially viable by the recent availability of low-cost integrated circuits operating at these frequencies. Although designed for the communication sector, these devices can perform the required UWB radar measurements as well. This paper reports the implementation of a 2 to 5 GHz bandwidth linear array scanner. The paper describes the design and fabrication of transmitter and receiver antenna arrays whose individual elements are a type of antipodal Vivaldi antenna. The antenna's frequency and angular response were simulated in CST Microwave Studio and compared with laboratory measurements. The data pre-processing methods of background subtraction and deconvolution are implemented to improve the image quality. The background subtraction method uses a reference dataset to remove antenna crosstalk and room reflections from the dataset. The deconvolution method uses a Wiener filter to "sharpen" the returned echoes which improves the resolution of the reconstructed image. The filter uses an impulse response reference dataset and a signal

  16. Medication Errors

    MedlinePlus

    ... to reduce the risk of medication errors to industry and others at FDA. Additionally, DMEPA prospectively reviews ... List of Abbreviations Regulations and Guidances Guidance for Industry: Safety Considerations for Product Design to Minimize Medication ...

  17. Medication Errors

    MedlinePlus

    Medicines cure infectious diseases, prevent problems from chronic diseases, and ease pain. But medicines can also cause harmful reactions if not used ... You can help prevent errors by Knowing your medicines. Keep a list of the names of your ...

  18. Robust identification of concealed dangerous substances using THz imaging spectroscopy

    NASA Astrophysics Data System (ADS)

    Nystad, Helle E.; Haakestad, Magnus W.; van Rheenen, Arthur D.

    2015-05-01

    False alarm rates must be kept sufficiently low if a method to detect and identify objects or substances is to be implemented in real life applications. This is also true when trying to detect and identify dangerous substances such as explosives and drugs that are concealed in packaging materials. THz technology may be suited to detect these substances, especially when imaging and spectroscopy are combined. To achieve reasonable throughput, the detection and identification process must be automated and this implies reliance on algorithms to perform this task, rather than human beings. The identification part of the algorithm must compare spectral features of the unknown substance with those in a library of features and determining the distance, in some sense, between these features. If the distance is less than some defined threshold a match is declared. In this paper we consider two types of spectral characteristic that are derived from measured time-domain signals measured in the THz regime: the absorbance and its derivative. Also, we consider two schemes to measure the distance between the unknown and library characteristics: Spectral Angle Mapping (SAM) and Principal Component Analysis (PCA). Finally, the effect of windowing of the measured time-domain signal on the performance of the algorithms is studied, by varying the Blackman-Harris (B-H) window width. Algorithm performance is quantified by studying the receiver-operating characteristics (ROC). For the data considered in this study we conclude that the best performance is obtained when the derivative of the absorbance is used in combination with a narrow B-H window and SAM. SAM is a more straight-forward method and requires no large training data sets and tweaking.

  19. Using fMRI to decode true thoughts independent of intention to conceal.

    PubMed

    Yang, Zhi; Huang, Zirui; Gonzalez-Castillo, Javier; Dai, Rui; Northoff, Georg; Bandettini, Peter

    2014-10-01

    Multi-variate pattern analysis (MVPA) applied to BOLD-fMRI has proven successful at decoding complicated fMRI signal patterns associated with a variety of cognitive processes. One cognitive process, not yet investigated, is the mental representation of "Yes/No" thoughts that precede the actual overt response to a binary "Yes/No" question. In this study, we focus on examining: (1) whether spatial patterns of the hemodynamic response carry sufficient information to allow reliable decoding of "Yes/No" thoughts; and (2) whether decoding of "Yes/No" thoughts is independent of the intention to respond honestly or dishonestly. To achieve this goal, we conducted two separate experiments. Experiment 1, collected on a 3T scanner, examined the whole brain to identify regions that carry sufficient information to permit significantly above-chance prediction of "Yes/No" thoughts at the group level. In Experiment 2, collected on a 7T scanner, we focused on the regions identified in Experiment 1 to examine the capability of achieving high decoding accuracy at the single subject level. A set of regions--namely right superior temporal gyrus, left supra-marginal gyrus, and left middle frontal gyrus--exhibited high decoding power. Decoding accuracy for these regions increased with trial averaging. When 18 trials were averaged, the median accuracies were 82.5%, 77.5%, and 79.5%, respectively. When trials were separated according to deceptive intentions (set via experimental cues), and classifiers were trained on honest trials, but tested on trials where subjects were asked to deceive, the median accuracies of these regions still reached 66%, 75%, and 78.5%. These results provide evidence that concealed "Yes/No" thoughts are encoded in the BOLD signal, retaining some level of independence from the subject's intentions to answer honestly or dishonestly. These findings also suggest the theoretical possibility for more efficient brain-computer interfaces where subjects only need to think

  20. Exploring the characteristics of the attentional blink paradigm when used to discover concealed knowledge.

    PubMed

    Niziurski, Julie; Andre, Jeffrey

    2015-12-01

    Ganis and Patnaik (Appl Psychophysiol Biofeedback 34:189-196, 2009) reported that the attentional blink paradigm using faces could be used to detect the presence of concealed knowledge. The attentional blink is defined as the inability to successfully detect the second of two target items presented within a short inter-stimulus interval. The present study tested the use of the attentional blink paradigm in a concealed knowledge test by investigating the effect that familiar faces may have on the attentional blink. Participants completed 200 trials where they were told to look for the same familiar target (Target 2; actor Brad Pitt) that was intermixed with neutral face stimuli and one other familiar face (Target 1; actor George Clooney). Target 1 was to act as the concealed knowledge as participants familiar with Target 1 would be distracted by his unannounced presence and report not seeing Target 2 thereby showing an attentional blink. Despite all participants being familiar with Target 2, an attentional blink still occurred, but with higher than normal Target 2 accuracy rates. Overall, we found support for using the AB paradigm with the concealed knowledge test; however, a possible countermeasure to the attentional blink is familiarity with Target 2 as eight of 21 participants who recognized Target 1 (the concealed knowledge) were also able to detect Target 2 on 100 % of the trials where Target 1's presence should have created an attentional blink. PMID:26162299

  1. A multifaceted active swept millimetre-wave approach to the detection of concealed weapons

    NASA Astrophysics Data System (ADS)

    Andrews, David A.; Bowring, Nicholas; Rezgui, Nacer D.; Southgate, Matthew; Guest, Elizabeth; Harmer, Stuart; Atiah, Ali

    2008-10-01

    The effective detection of concealed handguns and knives in open spaces is a major challenge for police and security services round the world. Here an automated technique for the detection of concealed handguns that relies on active swept illumination of the target to induce both scattered fields and aspect independent responses from the concealed object is presented. The broad frequency sweep permits information about the object's size to be deduced from transformations into the time/distance domain. In our experiments we collect multiple sweeps across the frequency range at very high speed, which produces a time evolved response from the target, from both normal and cross polarized detectors. From this we extract characteristic signatures from the responses that allow those from innocent objects (e.g. mobile phones, keys etc) to be distinguished from handguns. Information about the optical depth separation of the scattering corners and the degree and shape of cross polarization allows a neural network to successfully concealed handguns. Finally this system utilizes a range of signal processing techniques ranging from correlation between cross and normally polarized scattering through to a neural network classifier to deduce whether a concealed weapon is present.

  2. Biomimetic Concealing of PLGA Microspheres in a 3D Scaffold to Prevent Macrophage Uptake.

    PubMed

    Minardi, Silvia; Corradetti, Bruna; Taraballi, Francesca; Sandri, Monica; Martinez, Jonathan O; Powell, Sebastian T; Tampieri, Anna; Weiner, Bradley K; Tasciotti, Ennio

    2016-03-01

    Scaffolds functionalized with delivery systems for the release of growth factors is a robust strategy to enhance tissue regeneration. However, after implantation, macrophages infiltrate the scaffold, eventually initiating the degradation and clearance of the delivery systems. Herein, it is hypothesized that fully embedding the poly(d,l-lactide-co-glycolide acid) microspheres (MS) in a highly structured collagen-based scaffold (concealing) can prevent their detection, preserving the integrity of the payload. Confocal laser microscopy reveals that non-embedded MS are easily internalized; when concealed, J774 and bone marrow-derived macrophages (BMDM) cannot detect them. This is further demonstrated by flow cytometry, as a tenfold decrease is found in the number of MS engulfed by the cells, suggesting that collagen can cloak the MS. This correlates with the amount of nitric oxide and tumor necrosis factor-α produced by J774 and BMDM in response to the concealed MS, comparable to that found for non-functionalized collagen scaffolds. Finally, the release kinetics of a reporter protein is preserved in the presence of macrophages, only when MS are concealed. The data provide detailed strategies for fabricating three dimensional (3D) biomimetic scaffolds able to conceal delivery systems and preserve the therapeutic molecules for release. PMID:26797709

  3. How many more guns?: Estimating the effect of allowing licensed concealed handguns on a college campus.

    PubMed

    Bouffard, Jeffrey A; Nobles, Matt R; Wells, William; Cavanaugh, Michael R

    2012-01-01

    Among other arguments, advocates for lifting bans on carrying concealed handguns on campus propose that this would increase the prevalence of legitimately carried handguns, which might then deter crimes or be used to intervene in campus shooting incidents like the one that took place at Virginia Tech in 2007. Opponents suggest that increased prevalence of concealed handguns would lead to increases in other negative consequences, such as accidental shootings. Little empirical research has examined the potential outcomes of such a policy change, nor has existing research examined the prerequisite issue of whether lifting these bans would result in substantial increases in the prevalence of concealed handguns among students. Using a sample of undergraduate classrooms selected from five academic buildings at a public university in Texas, this study examines the potential impact of lifting the concealed handgun ban on the likelihood that a given classroom would contain at least one legally carried handgun. Results reveal that the impact of potential policy changes in this area vary based on the building under consideration and the measure of potential handgun prevalence. Limitations of the study and implications for future research on the issue of concealed handgun carrying on college campuses are discussed. PMID:21810786

  4. The neural substrates of deliberative decision making: contrasting effects of hippocampus lesions on performance and vicarious trial-and-error behavior in a spatial memory task and a visual discrimination task

    PubMed Central

    Bett, David; Allison, Elizabeth; Murdoch, Lauren H.; Kaefer, Karola; Wood, Emma R.; Dudchenko, Paul A.

    2012-01-01

    Vicarious trial-and-errors (VTEs) are back-and-forth movements of the head exhibited by rodents and other animals when faced with a decision. These behaviors have recently been associated with prospective sweeps of hippocampal place cell firing, and thus may reflect a rodent model of deliberative decision-making. The aim of the current study was to test whether the hippocampus is essential for VTEs in a spatial memory task and in a simple visual discrimination (VD) task. We found that lesions of the hippocampus with ibotenic acid produced a significant impairment in the accuracy of choices in a serial spatial reversal (SR) task. In terms of VTEs, whereas sham-lesioned animals engaged in more VTE behavior prior to identifying the location of the reward as opposed to repeated trials after it had been located, the lesioned animals failed to show this difference. In contrast, damage to the hippocampus had no effect on acquisition of a VD or on the VTEs seen in this task. For both lesion and sham-lesion animals, adding an additional choice to the VD increased the number of VTEs and decreased the accuracy of choices. Together, these results suggest that the hippocampus may be specifically involved in VTE behavior during spatial decision making. PMID:23115549

  5. Use of Near-Infrared Spectroscopy and Chemometrics for the Nondestructive Identification of Concealed Damage in Raw Almonds (Prunus dulcis).

    PubMed

    Rogel-Castillo, Cristian; Boulton, Roger; Opastpongkarn, Arunwong; Huang, Guangwei; Mitchell, Alyson E

    2016-07-27

    Concealed damage (CD) is defined as a brown discoloration of the kernel interior (nutmeat) that appears only after moderate to high heat treatment (e.g., blanching, drying, roasting, etc.). Raw almonds with CD have no visible defects before heat treatment. Currently, there are no screening methods available for detecting CD in raw almonds. Herein, the feasibility of using near-infrared (NIR) spectroscopy between 1125 and 2153 nm for the detection of CD in almonds is demonstrated. Almond kernels with CD have less NIR absorbance in the region related with oil, protein, and carbohydrates. With the use of partial least squares discriminant analysis (PLS-DA) and selection of specific wavelengths, three classification models were developed. The calibration models have false-positive and false-negative error rates ranging between 12.4 and 16.1% and between 10.6 and 17.2%, respectively. The percent error rates ranged between 8.2 and 9.2%. Second-derivative preprocessing of the selected wavelength resulted in the most robust predictive model. PMID:27309980

  6. Influence of low-spatial frequency ripples in machined potassium dihydrogen phosphate crystal surfaces on wavefront errors based on the wavelet method

    NASA Astrophysics Data System (ADS)

    Chen, Wanqun; Sun, Yazhou

    2015-02-01

    In using a fly cutter to machine potassium dihydrogen phosphate (KDP) crystals, rippling in machined surfaces will remain that will have a significant impact on the optical performance. An analysis of these low-spatial frequency ripples is presented and its influence on the root-mean-squared gradient (GRMS) of the wavefront discussed. A frequency analysis of the machined KDP crystal surfaces is performed using wavelet transform and power spectral density methods. Based on a classification of the time frequencies for these macroripples, the multimode vibration of the machine tool is found to be the main reason surface ripples are produced. Improvements in the machine design parameters are proposed to limit such effects on the wavefront performance of the KDP crystal.

  7. Systematic lossy forward error protection for error-resilient digital video broadcasting

    NASA Astrophysics Data System (ADS)

    Rane, Shantanu D.; Aaron, Anne; Girod, Bernd

    2004-01-01

    We present a novel scheme for error-resilient digital video broadcasting,using the Wyner-Ziv coding paradigm. We apply the general framework of systematic lossy source-channel coding to generate a supplementary bitstream that can correct transmission errors in the decoded video waveform up to a certain residual distortion. The systematic portion consists of a conventional MPEG-coded bitstream, which is transmitted over the error-prone channel without forward error correction.The supplementary bitstream is a low rate representation of the transmitted video sequence generated using Wyner-Ziv encoding. We use the conventionally decoded error-concealed MPEG video sequence as side information to decode the Wyner-Ziv bits. The decoder combines the error-prone side information and the Wyner-Ziv description to yield an improved decoded video signal. Our results indicate that, over a large range of channel error probabilities, this scheme yields superior video quality when compared with traditional forward error correction techniques employed in digital video broadcasting.

  8. Noradrenergic signaling in the medial prefrontal cortex and amygdala differentially regulates vicarious trial-and-error in a spatial decision-making task.

    PubMed

    Amemiya, Seiichiro; Kubota, Natsuko; Umeyama, Nao; Nishijima, Takeshi; Kita, Ichiro

    2016-01-15

    In uncertain choice situations, we deliberately search and evaluate possible options before taking an action. Once we form a preference regarding the current situation, we take an action more automatically and with less deliberation. In rats, the deliberation process can be seen in vicarious trial-and-error behavior (VTE), which is a head-orienting behavior toward options at a choice point. Recent neurophysiological findings suggest that VTE reflects the rat's thinking about future options as deliberation, expectation, and planning when rats feel conflict. VTE occurs depending on the demand: an increase occurs during initial learning, and a decrease occurs with progression in learning. However, the brain circuit underlying the regulation of VTE has not been thoroughly examined. In situations in which VTE often appears, the medial prefrontal cortex (mPFC) and the amygdala (AMY) are crucial for learning and decision making. Our previous study reported that noradrenaline regulates VTE. Here, to investigate whether the mPFC and AMY are involved in regulation of VTE, we examined the effects of local injection of clonidine, an alpha2 adrenergic autoreceptor agonist, into either region in rats during VTE and choice behavior during a T-maze choice task. Injection of clonidine into either region impaired selection of the advantageous choice in the task. Furthermore, clonidine injection into the mPFC suppressed occurrence of VTE in the early phase of the task, whereas injection into the AMY inhibited the decrease in VTE in the later phase and thus maintained a high level of VTE throughout the task. These results suggest that the mPFC and AMY play a role in the increase and decrease in VTE, respectively, and that noradrenergic mechanisms mediate the dynamic regulation of VTE over experiences. PMID:26341318

  9. The role of psychological flexibility in the relationship between self-concealment and disordered eating symptoms.

    PubMed

    Masuda, Akihiko; Boone, Matthew S; Timko, C Alix

    2011-04-01

    The present cross-sectional study investigated whether psychological flexibility mediates the association between self-concealment and disordered eating (DE) symptoms among non-clinical college students. Data of 209 male and female participants (nfemale =165), aged 18-22 years old, were used for analyses. Self-concealment was found to be positively associated with DE symptoms (i.e., general eating disorder symptoms and eating disorder-related cognitions) and negatively associated with psychological flexibility. Psychological flexibility was inversely associated with DE symptoms. Finally, psychological flexibility was found to mediate the association between self-concealment and DE symptoms after accounting for gender, ethnic background, and body mass index (BMI). PMID:21385643

  10. Real-time computational processing and implementation for concealed object detection

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Su; Yeom, Seokwon; Chang, YuShin; Lee, Mun-Kyo; Jung, Sang-Won

    2012-07-01

    Millimeter wave (MMW) readily penetrates fabrics, thus it can be used to detect objects concealed under clothing. A passive MMW imaging system can operate as a stand-off type sensor that scans people both indoors and outdoors. However, because of the diffraction limit and low signal level, the imaging system often suffers from low image quality. Therefore, suitable computational processing would be required for automatic analysis of the images. The authors present statistical and computational algorithms and their implementations for real-time concealed object detection. The histogram of the image is modeled as a Gaussian mixture distribution, and hidden object areas are segmented by a multilevel scheme involving the expectation-maximization algorithm. The complete algorithm has been implemented in both MATLAB and C++. Experimental and simulation results confirm that the implemented system can achieve real-time detection of concealed objects.

  11. Combining the P300-complex trial-based concealed information test and the reaction time-based autobiographical implicit association test in concealed memory detection.

    PubMed

    Hu, Xiaoqing; Rosenfeld, J Peter

    2012-08-01

    Despite the P300-concealed information test's validity in detecting concealed memory when it is conducted immediately after the mock crime, whether the P300-CIT's detection efficiency is moderated by time delay remains unknown. Here, we conducted a mock crime study in which guilty participants were tested immediately after the mock crime or 1 month later. An innocent group was also tested. Assuming that the autobiographical Implicit Association Test (aIAT) and the P300-CIT rely on nonoverlapping mechanisms for memory detection, participants were tested using both the P300-CIT and the reaction time (RT)-based aIAT. Results suggested that the sensitivity of both tests remains even after the 1-month delay. The indicators from the RT-aIAT and P300-CIT were uncorrelated, thus combining P300-CIT and aIAT data further increased the efficiency of memory detection. PMID:22681260

  12. The association between concealing emotions at work and medical utilization in Korea

    PubMed Central

    2014-01-01

    Objectives We aimed to investigate the association between concealing emotions at work and medical utilization. Methods Data from the 2007–2009 4th Korea National Health and Nutrition Examination Survey (KNHANES IV) was used, 7,094 participants (3,837 males, 3,257 females) aged between 20 and 54 who were economically active and completed all necessary questionnaire items were included. Odds ratios (ORs) and 95% confidence intervals (95% CI) for differences in hospitalization, outpatient visits, and pharmaceutical drug use between those who concealed their emotions and those who did not were investigated using logistic regression models with and without gender stratification. Results Among those who concealed their emotions (n = 2,763), 47.4% were females, and 50.1% had chronic disease. In addition, 9.7% of the concealing emotions group had been hospitalized within the last year, 24.8% had been outpatients in the last two weeks, and 28.3% had used pharmaceutical drugs in the last two weeks. All ORs represent the odds of belonging to the concealing emotions group over the non-concealing emotions group. After adjustment for individual, occupational, socioeconomic and disease factors, the adjusted ORs (95% CI) in hospitalization are 1.29 (1.08 ~ 1.53) in the total population, 1.25 (0.98 ~ 1.60) in males and 1.30 (1.02 ~ 1.66) in females, in outpatient visits are 1.15 (1.02 ~ 1.29) in the total population, 1.05 (0.88 ~ 1.24) in males and 1.25 (1.06 ~ 1.47) in females and in pharmaceutical drug use are 1.12 (1.01 ~ 1.25) in the total population, 1.08 (0.92 ~ 1.27) in males and 1.14 (0.98 ~ 1.33) in females. Conclusions Those who concealed their emotions at work were more likely to use medical services. Moreover, the health effects of concealing emotions at work might be more detrimental in women than in men. PMID:25852941

  13. The Role of Stigma Concealment in the Retrospective High School Experiences of Gay, Lesbian, and Bisexual Individuals

    ERIC Educational Resources Information Center

    Frost, David M.; Bastone, Linda M.

    2008-01-01

    High school is a time when most gay, lesbian, and bisexual (GLB) youths experience a great deal of distress related to the stigma attached to being gay. Many try to avoid stigmatization by concealing the fact that they are GLB. This brief report presents a descriptive, multidimensional approach to understanding GLB stigma concealment as a…

  14. The effects of asymmetric vs. symmetric probability of targets following probe and irrelevant stimuli in the complex trial protocol for detection of concealed information with P300.

    PubMed

    Rosenfeld, J Peter; Tang, Monica; Meixner, John; Winograd, Michael; Labkovsky, Elena

    2009-08-01

    The complex trial protocol (CTP, [J.P. Rosenfeld, E. Labkovsky, M. Winograd, M.A. Lui, C. Vandenboom & E. Chedid (2008), The complex trial protocol (CTP): a new, countermeasure-resistant, accurate P300-based method for detection of concealed information. Psychophysiology, 45, 906-919.]) is a sensitive, new, countermeasure-resistant, P300-based concealed information protocol in which a first stimulus (Probe or Irrelevant) is followed after about 1.4-1.8 s by a Target or Non-Target second stimulus within one trial. It has been previously run with a potentially confounding asymmetric conditional probability of Targets following Probes vs. Irrelevants. This present study compared asymmetric vs. symmetric conditional probability groups and found no significant differences in detection rates or Probe-minus-Irrelevant P300 differences between groups. Group differences were seen in error rates and reaction times (RT) to second stimuli. These differences were, however, not diagnostic for deception vs. truth-telling, and were attributable to response perseveration. PMID:19374912

  15. Detecting concealed information using feedback related event-related brain potentials.

    PubMed

    Sai, Liyang; Lin, Xiaohong; Hu, Xiaoqing; Fu, Genyue

    2014-10-01

    Employing an event-related potential (ERP)-based concealed information test (CIT), the present study investigated (1) the neurocognitive processes when people received feedbacks regarding their deceptive/truthful responses and (2) whether such feedback-related ERP activities can be used to detect concealed information above and beyond the recognition-related P300. During the CIT, participants were presented with rare, meaningful probes (their own names) embedded within a series of frequent yet meaningless irrelevants (others' names). Participants were instructed to deny their recognition of the probes. Critically, following participants' responses, they were provided with feedbacks regarding whether they succeeded or failed in the CIT. Replicating previous ERP-based CITs, we found a larger P300 elicited by probe compared to irrelevant. Regarding feedback-related ERPs, a temporospatial Principle Component Analyses found two ERP components that were not only sensitive to feedback manipulations but also can discriminate probe from irrelevant: an earlier, central-distributed positivity that was elicited by "success" feedbacks peaked around 219ms; and a later, right central-distributed positivity that was also elicited by "success" feedbacks, peaked around 400ms. Importantly, the feedback ERPs were not correlated with P300 that was elicited by probe/irrelevant, suggesting that these two ERPs reflect independent processes underlying memory concealment. These findings illustrate the feasibility and promise of using feedback-related ERPs to detect concealed memory and thus deception. PMID:25058495

  16. Fear Perceptions in Public Parks: Interactions of Environmental Concealment, the Presence of People Recreating, and Gender

    ERIC Educational Resources Information Center

    Jorgensen, Lisa J.; Ellis, Gary D.; Ruddell, Edward

    2013-01-01

    This research examined the effect of concealment (environmental cues), presence or absence of people recreating (social cues), and gender on individuals' fear of crime in a community park setting. Using a 7-point single-item indicator, 732 participants from two samples (540 park visitors and 192 college students) rated their estimates of fear…

  17. Orienting versus inhibition in the Concealed Information Test: Different cognitive processes drive different physiological measures.

    PubMed

    Selle, Nathalie Klein; Verschuere, Bruno; Kindt, Merel; Meijer, Ewout; Ben-Shakhar, Gershon

    2016-04-01

    The Concealed Information Test (CIT) provides a valid tool for psychophysiological detection of concealed knowledge. However, its precise theoretical underpinnings remain a matter of debate. The differential physiological responses elicited by concealed, relevant items, relative to control items, were traditionally explained as reflecting an orienting response (OR). According to an alternative account, these responses reflect attempts to inhibit arousal. The present study examined whether and to what extent CIT detection efficiency is affected by instructions aimed at manipulating arousal inhibition (AI). One hundred and forty-eight undergraduate students completed a CIT, while electrodermal, cardiac, and respiratory measures were recorded. Half of the participants were requested to imagine that they are suspected of committing a crime and were motivated to avoid detection (presumably eliciting both OR and AI), while the other half were requested to imagine that they are witnesses of a crime and were motivated to be detected (presumably eliciting OR only). All participants were further requested to remain silent throughout the test. In both conditions, concealed items led to a similar increase in skin conductance as compared to the control items. However, the typically observed heart rate deceleration and respiratory suppression were found in suspects, but not in witnesses. These data imply that different mechanisms drive the responding of different psychophysiological measures used in the CIT, with skin conductance reflecting OR, and heart rate and respiration primarily reflecting AI. PMID:26615984

  18. Ego Identity, Social Anxiety, Social Support, and Self-Concealment in Lesbian, Gay, and Bisexual Individuals

    ERIC Educational Resources Information Center

    Potoczniak, Daniel J.; Aldea, Mirela A.; DeBlaere, Cirleen

    2007-01-01

    This study examined a model in which the relationship between social anxiety and two dimensions of ego identity (commitment and exploration) was expected to be mediated by social support and self-concealment for a sample of lesbian, gay, and bisexual individuals (N=347). Statistically significant paths were found from social anxiety to social…

  19. Anxiety and Related Disorders and Concealment in Sexual Minority Young Adults.

    PubMed

    Cohen, Jeffrey M; Blasey, Christine; Barr Taylor, C; Weiss, Brandon J; Newman, Michelle G

    2016-01-01

    Sexual minorities face greater exposure to discrimination and rejection than heterosexuals. Given these threats, sexual minorities may engage in sexual orientation concealment in order to avoid danger. This social stigma and minority stress places sexual minorities at risk for anxiety and related disorders. Given that three fourths of anxiety disorder onset occurs before the age of 24, the current study investigated the symptoms of generalized anxiety disorder, social phobia, panic disorder, posttraumatic stress disorder, and depression in sexual minority young adults relative to their heterosexual peers. Secondarily, the study investigated sexual orientation concealment as a predictor of anxiety and related disorders. A sample of 157 sexual minority and 157 heterosexual young adults matched on age and gender completed self-report measures of the aforementioned disorders, and indicated their level of sexual orientation concealment. Results revealed that sexual minority young adults reported greater symptoms relative to heterosexuals across all outcome measures. There were no interactions between sexual minority status and gender, however, women had higher symptoms across all disorders. Sexual minority young women appeared to be at the most risk for clinical levels of anxiety and related disorders. In addition, concealment of sexual orientation significantly predicted symptoms of social phobia. Implications are offered for the cognitive and behavioral treatment of anxiety and related disorders in this population. PMID:26763500

  20. 36-Month-Olds Conceal Visual and Auditory Information from Others

    ERIC Educational Resources Information Center

    Melis, Alicia P.; Call, Josep; Tomasello, Michael

    2010-01-01

    By three years of age, children are skilled at assessing under which circumstances others can see things. However, nothing is known about whether they can use this knowledge to guide their own deceptive behaviour. Here we investigated 3-year-olds' ability to strategically inhibit or conceal forbidden actions that a nearby adult experimenter could…

  1. Productive and Inclusive? How Documentation Concealed Racialising Practices in a Diversity Project

    ERIC Educational Resources Information Center

    Miller, Melinda G.

    2014-01-01

    This article examines how documentation concealed racialising practices in a diversity project that was seen to be productive and inclusive. Documentation examples are taken from a doctoral study about embedding Indigenous perspectives in early childhood education curricula in two Australian urban childcare centres. In place of reporting examples…

  2. University Presidents' Perceptions and Practice Regarding the Carrying of Concealed Handguns on College Campuses

    ERIC Educational Resources Information Center

    Price, James H.; Thompson, Amy; Khubchandani, Jagdish; Dake, Joseph; Payton, Erica; Teeple, Karen

    2014-01-01

    Objective: To assess the perceptions and practices of a national sample of college and university presidents regarding their support for concealed handguns being carried on college campuses. Participants: The sample for this study consisted of a national random sample of 900 college or university presidents. Methods: In the spring of 2013, a…

  3. Digital image processing in the SECURE concealed-object detection system

    NASA Astrophysics Data System (ADS)

    Smith, Steven W.

    1993-04-01

    A new technology has been developed for detecting explosives and other dangerous objects concealed under persons' clothing. The 'Subambient Exposure, Computer Utilized Reflected Energy' (SECURE) method uses a very low level of back-scattered x-rays in conjunction with digital image processing to produce an image of the person and any concealed objects. Image processing algorithms, used in the system are directed at presenting information to a human operator in the best possible manner for foreign object detection. These algorithms are viewed as being near optimum, and additional development is probably not justified. Algorithm development is needed in the area of automatic threat detection. This has the potential of reducing the invasion of privacy associated with having a security operator view each image. It also has the potential of reducing the serious problem of operator complacency. In one approach, the new algorithm must (1) recognize and isolate objects in the image, (2) discriminate between concealed objects and human anatomy, and (3) discriminate between dangerous and benign concealed objects. The images produced with the SECURE technology are extremely noisy due to the low levels of radiation used. Any algorithm developed must perform well in this noisy environment. Execution of the algorithm must be accomplished in less than a few seconds. Hardware to implement the algorithm must be of a complexity and cost compatible with the commercial SECURE system.

  4. A non-imaging polarized terahertz passive system for detecting and identifying concealed explosives

    NASA Astrophysics Data System (ADS)

    Karam, Mostafa A.; Meyer, Doug

    2011-06-01

    Existing terahertz THz systems for detecting concealed explosives are not capable of identifying explosive type which leads to higher false alarm rates. Moreover, some of those systems are imaging systems that invade personal privacy, and require more processing and computational resources. Other systems have no polarization preference which makes them incapable of capturing the geometric features of an explosive. In this study a non-imaging polarized THz passive system for detecting and identifying concealed explosives overcoming the forgoing shortcomings is developed. The system employs a polarized passive THz sensor in acquiring emitted data from a scene that may have concealed explosives. The acquired data are decomposed into their natural resonance frequencies, and the number of those frequencies is used as criteria in detecting the explosive presence. If the presence of an explosive is confirmed, a set of physically based retrieval algorithms is used in extracting the explosive dielectric constant/refractive index value from natural resonance frequencies and amplitudes of associated signals. Comparing the refractive index value against a database of refractive indexes of known explosives identifies the explosive type. As an application, a system having a dual polarized radiometer operating within the frequency band of 0.62- 0.82 THz is presented and used in detecting and identifying person borne C-4 explosive concealed under a cotton garment. The system showed higher efficiencies in detecting and identifying the explosive.

  5. How Many More Guns?: Estimating the Effect of Allowing Licensed Concealed Handguns on a College Campus

    ERIC Educational Resources Information Center

    Bouffard, Jeffrey A.; Nobles, Matt R.; Wells, William; Cavanaugh, Michael R.

    2012-01-01

    Among other arguments, advocates for lifting bans on carrying concealed handguns on campus propose that this would increase the prevalence of legitimately carried handguns, which might then deter crimes or be used to intervene in campus shooting incidents like the one that took place at Virginia Tech in 2007. Opponents suggest that increased…

  6. The Cost of Question Concealment: Eye-Tracking and MEG Evidence

    ERIC Educational Resources Information Center

    Harris, Jesse; Pylkkanen, Liina; McElree, Brian; Frisson, Steven

    2008-01-01

    Although natural language appears to be largely compositional, the meanings of certain expressions cannot be straightforwardly recovered from the meanings of their parts. This study examined the online processing of one such class of expressions: "concealed questions", in which the meaning of a complex noun phrase ("the proof of the theorem")…

  7. Shape-descriptor-based detection of concealed weapons in millimeter-wave data

    NASA Astrophysics Data System (ADS)

    Slamani, Mohamed-Adel; Ferris, David D., Jr.

    2001-03-01

    Shape parameters based on circularity, Fourier descriptors, and invariant moments are studied for the automatic detection of weapons in millimeter-wave data. The data is collected by a 30-frames-per-second millimeter-wave (MMW) imager manufactured by Trex Enterprises for the detection of weapons concealed underneath a person's clothing. Results are illustrated through processing real MMW data.

  8. The Effects of Concealing Academic Achievement Information on Adolescents' Self-Concept

    ERIC Educational Resources Information Center

    Zhang, Baoshan; Wang, Mo; Li, Juan; Yu, Guoliang; Bi, Yan-Ling

    2011-01-01

    Using an experimental design, the effect of concealing academic achievement information on adolescents' self-concept was examined in the current study. Specifically, adolescents with low academic achievement and adolescents with average to high academic achievement (N = 129) were randomly assigned to different interview contexts wherein…

  9. Smoothing error pitfalls

    NASA Astrophysics Data System (ADS)

    von Clarmann, T.

    2014-09-01

    The difference due to the content of a priori information between a constrained retrieval and the true atmospheric state is usually represented by a diagnostic quantity called smoothing error. In this paper it is shown that, regardless of the usefulness of the smoothing error as a diagnostic tool in its own right, the concept of the smoothing error as a component of the retrieval error budget is questionable because it is not compliant with Gaussian error propagation. The reason for this is that the smoothing error does not represent the expected deviation of the retrieval from the true state but the expected deviation of the retrieval from the atmospheric state sampled on an arbitrary grid, which is itself a smoothed representation of the true state; in other words, to characterize the full loss of information with respect to the true atmosphere, the effect of the representation of the atmospheric state on a finite grid also needs to be considered. The idea of a sufficiently fine sampling of this reference atmospheric state is problematic because atmospheric variability occurs on all scales, implying that there is no limit beyond which the sampling is fine enough. Even the idealization of infinitesimally fine sampling of the reference state does not help, because the smoothing error is applied to quantities which are only defined in a statistical sense, which implies that a finite volume of sufficient spatial extent is needed to meaningfully discuss temperature or concentration. Smoothing differences, however, which play a role when measurements are compared, are still a useful quantity if the covariance matrix involved has been evaluated on the comparison grid rather than resulting from interpolation and if the averaging kernel matrices have been evaluated on a grid fine enough to capture all atmospheric variations that the instruments are sensitive to. This is, under the assumptions stated, because the undefined component of the smoothing error, which is the

  10. Concealed explosive detection on personnel using a wideband holographic millimeter-wave imaging system

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; McMakin, Douglas L.; Collins, H. D.; Hall, Thomas E.; Severtsen, Ronald H.

    1996-06-01

    A novel wideband millimeter-wave imaging system is presently being developed at Pacific Northwest National Laboratory (PNNL) that will allow rapid inspection of personnel for concealed explosives, handguns, or other threats. Millimeter-wavelength electromagnetic waves are effective for this application since they readily penetrate common clothing materials, while being partially reflected from the person under surveillance as well as any concealed items. To form an image rapidly, a linear array of 128 antennas is used to electronically scan over a horizontal aperture of 0.75 meters, while the linear array is mechanically swept over a vertical aperture of 2 meters. At each point over this 2-D aperture, coherent wideband data reflected from the target is gathered using wide-beamwidth antennas. The data is recorded coherently, and reconstructed (focused) using an efficient image reconstruction algorithm developed at PNNL. This algorithm works in the near-field of both the target and the scanned aperture and preserves the diffraction limited resolution of less than one-wavelength. The wide frequency bandwidth is used to provide depth resolution, which allows the image to be fully focused over a wide range of depths, resulting in a full 3-D image. This is not possible in a normal optical (or quasi-optical) imaging system. This system has been extensively tested using concealed metal and plastic weapons, and has recently been tested using real plastic explosives (C-4 and RDX) and simulated liquid explosives concealed on personnel. Millimeter-waves do not penetrate the human body, so it is necessary to view the subject from several angles in order to fully inspect for concealed weapons. Full animations containing 36 - 72 frames recorded from subjects rotated by 5 - 10 degrees, have been found to be extremely useful for rapid, effective inspection of personnel.

  11. Spatial alexia.

    PubMed

    Ardila, A; Rosselli, M

    1994-05-01

    Twenty-one patients with right hemisphere damage were studied (11 men, 10 women; average age = 41.33; range = 19-65). Patients were divided in two groups: pre-Rolandic (six patients) and retro-Rolandic (15 patients) right hemisphere damage. A special reading test was given to each patient. The observed errors included: literal errors (substitutions, additions, and omissions of letters), substitutions of syllables and pseudowords for meaningful words, left hemispatial neglect, confabulation, splitting of words, verbal errors (substitutions, additions, and omission of words), grouping of letters belonging to two different words, misuse of punctuation marks, and errors in following lines. It was proposed that spatial alexia is characterized by: (1) some difficulties in the recognition of the spatial orientation in letters; (2) left hemispatial neglect; (3) tendency to "complete" the sense of words and sentences; (4) inability to follow lines when reading texts, and sequentially explore the spatial distribution of the written material; and (5) grouping and fragmentation of words, most likely as a consequence of the inability to interpret the relative value of spaces between letters correctly. PMID:7960468

  12. Results of software error-data experiments

    NASA Technical Reports Server (NTRS)

    Finelli, George B.

    1988-01-01

    In order to evaluate existing software reliability models and proposed modeling approaches, a search was conducted for data on the software failure process. This search revealed that the data necessary for this evaluation were not available. As a result, a research effort was initiated by NASA to generate data on which to base the development of credible methods for assessing the reliability of software targeted for flight-crucial applications. Two sets of software error-data experiments were conducted by different research groups. The results of the experiments were consistent: errors caused by different faults in a program occurred at widely varying rates; program failure rates exhibited a log-linear trend with respect to the number of faults corrected; some faults were found to interact in either concealing or revealing ways; and contiguous regions of the input space which cause a program to generate errors, called error crystals, were found and characterized for some faults. Collectively, these experiments have produced information on software failure which must be accounted for in software reliability modeling approaches.

  13. Concealed threat detection with the IRAD sub-millimeter wave 3D imaging radar

    NASA Astrophysics Data System (ADS)

    Robertson, Duncan A.; Cassidy, Scott L.; Jones, Ben; Clark, Anthony

    2014-06-01

    Sub-millimeter wave 3D imaging radar is a promising technology for the stand-off detection of threats concealed on people. The IRAD 340 GHz 3D imaging radar uses polarization intensity information to identify signatures associated with concealed threats. We report on an extensive trials program which has been carried out involving dozens of individual subjects wearing a variety of different clothing to evaluate the detection of a wide range of threat and benign items. We have developed an automatic algorithm to run on the radar which yields a level of anomaly indication in real time. Statistical analysis of the large volume of recorded data has enabled performance metrics for the radar system to be evaluated.

  14. Time-delay concealment and complexity enhancement of an external-cavity laser through optical injection.

    PubMed

    Li, Nianqiang; Pan, Wei; Locquet, A; Citrin, D S

    2015-10-01

    The concealment of the time-delay signature (TDS) of chaotic external-cavity lasers is necessary to ensure the security of optical chaos-based cryptosystems. We show that this signature can be removed simply by optically injecting an external-cavity laser with a large linewidth-enhancement factor into a second, noninjection-locked, semiconductor laser. Concealment is ensured both in the amplitude and in the phase of the optical field, satisfying a sought-after property of optical chaos-based communications. Meanwhile, enhancement of the dynamical complexity, characterized by permutation entropy, coincides with strong TDS suppression over a wide range of parameters, the area for which depends sensitively on the linewidth-enhancement factor. PMID:26421545

  15. Identifying the location of a concealed object through unintentional eye movements.

    PubMed

    Neuman, Yair; Assaf, Dan; Israeli, Navot

    2015-01-01

    In some investigative and interrogative contexts, the investigator is seeking to identify the location of an object (e.g., implanted bomb) which is known to a given subject (e.g., a terrorist). In this paper, we present a non-intrusive methodology for uncovering the loci of a concealed object by analyzing the subject's eye movements. Using a combination of eye tracking, psychological manipulation and a search algorithm, we have performed two experiments. In the first experiment, we have gained 58% hit rate in identifying the location of the concealed object and in the second experiment 56% hit rate. The pros and cons of the methodology for forensic investigation are discussed. PMID:25904879

  16. Identifying the location of a concealed object through unintentional eye movements

    PubMed Central

    Neuman, Yair; Assaf, Dan; Israeli, Navot

    2015-01-01

    In some investigative and interrogative contexts, the investigator is seeking to identify the location of an object (e.g., implanted bomb) which is known to a given subject (e.g., a terrorist). In this paper, we present a non-intrusive methodology for uncovering the loci of a concealed object by analyzing the subject's eye movements. Using a combination of eye tracking, psychological manipulation and a search algorithm, we have performed two experiments. In the first experiment, we have gained 58% hit rate in identifying the location of the concealed object and in the second experiment 56% hit rate. The pros and cons of the methodology for forensic investigation are discussed. PMID:25904879

  17. Terahertz absorbance spectrum fitting method for quantitative detection of concealed contraband

    NASA Astrophysics Data System (ADS)

    Wang, Yingxin; Zhao, Ziran; Chen, Zhiqiang; Kang, Kejun; Feng, Bing; Zhang, Yan

    2007-12-01

    We present a quantitative method for the nondestructive detection of concealed contraband based on terahertz transmission spectroscopy. Without knowing the prior information of barrier materials, the amount of concealed contraband can be extracted by approximating the terahertz absorbance spectrum of the barrier material with a low-order polynomial and then fitting the measured absorbance spectrum of the inspected object with the polynomial and the known standard spectrum of this kind of contraband. We verify the validity of this method using a sample of explosive 1,3,5-trinitro-s-triazine (RDX) covered with several different barrier materials which are commonly encountered in actual inspection, and good agreement between the calculated and actual value of the amount of RDX is obtained for the experiments performed under both nitrogen and air atmospheres. This indicates that the presented method can achieve quantitative detection of hidden contraband, which is important for security inspection applications.

  18. Unsupervised image segmentation for passive THz broadband images for concealed weapon detection

    NASA Astrophysics Data System (ADS)

    Ramírez, Mabel D.; Dietlein, Charles R.; Grossman, Erich; Popović, Zoya

    2007-04-01

    This work presents the application of a basic unsupervised classification algorithm for the segmentation of indoor passive Terahertz images. The 30,000 pixel broadband images of a person with concealed weapons under clothing are taken at a range of 0.8-2m over a frequency range of 0.1-1.2THz using single-pixel row-based raster scanning. The spiral-antenna coupled 36x1x0.02μm Nb bridge cryogenic micro-bolometers are developed at NIST-Optoelectronics Division. The antenna is evaporated on a 250μm thick Si substrate with a 4mm diameter hyper-hemispherical Si lens. The NETD of the microbolometer is 125mK at an integration time of 30 ms. The background temperature calibration is performed with a known 25 pixel source above 330 K, and a measured background fluctuation of 200-500mK. Several weapons were concealed under different fabrics: cotton, polyester, windblocker jacket and thermal sweater. Measured temperature contrasts ranged from 0.5-1K for wrinkles in clothing to 5K for a zipper and 8K for the concealed weapon. In order to automate feature detection in the images, some image processing and pattern recognition techniques have been applied and the results are presented here. We show that even simple algorithms, that can potentially be performed in real time, are capable of differentiating between a metal and a dielectric object concealed under clothing. Additionally, we show that pre-processing can reveal low temperature contrast features, such as folds in clothing.

  19. Antidromic Atrioventricular Reciprocating Tachycardia Using a Concealed Retrograde Conducting Left Lateral Accessory Pathway.

    PubMed

    Gonzalez, Jaime E; Zipse, Matthew M; Nguyen, Duy T; Sauer, William H

    2016-03-01

    Atrioventricular reciprocating tachycardia is a common cause of undifferentiated supraventricular tachycardia. In patients with manifest or concealed accessory pathways, it is imperative to assess for the presence of other accessory pathways. Multiple accessory pathways are present in 4% to 10% of patients and are more common in patients with structural heart disease. In rare cases, multiple accessory pathways can act as the anterograde and retrograde limbs of the tachycardia. PMID:26920167

  20. Tracheal tube obstruction in a case of concealed tracheomalacia--a case report.

    PubMed

    Athanassiou, L; Charissi, N

    2005-06-01

    We report on the successful mangement of airway obstruction, immediately after tracheal intubation for elective operation, in a patient with concealed tracheomalacia. We discuss the issues posed in patients with mild or undiagnosed chronic obstructive pulmonary disease (COPD) that are relevant to tracheomalacia. We underline the link between tracheomalacia and COPD and emphasize the high level of awareness needed, in order to avoid or manage promptly adverse events during airway management for anesthesia in these patients. PMID:16438015

  1. ARPA/NIJ/Rome Laboratory concealed weapon detection program: an overview

    NASA Astrophysics Data System (ADS)

    Currie, Nicholas C.; Demma, Fred J.; Ferris, David D., Jr.; McMillan, Robert W.; Wicks, Michael C.

    1996-06-01

    Recent advances in passive and active imaging and non- imaging sensor technology offer the potential to detect weapons that are concealed beneath a person's clothing. Sensors that are discussed in this paper are characterized as either non-imaging or imaging. Non-imaging sensors include wide band radar and portal devices such as metal detectors. In general the strength of non-imaging sensors rest with the fact that they are generally inexpensive and can rapidly perform bulk separation between regions where persons are likely to be carrying concealed weapons and those regions that are likely to contain persons who are unarmed. The bulk process is typically accomplished at the expense of false alarm rate. Millimeter-wave (MMW), microwave, x-ray, acoustic, magnetic, and infrared (IR) imaging sensor technologies provide with greater certainty the means to isolate persons within a crowd that are carrying concealed weapons and to identify the weapon type. The increased certainty associated with imaging sensors is accomplished at the expense of cost and bulk surveillance of the crowd. CWD technologies have a variety of military and civilian applications. This technology focus area addresses specific military needs under the Defense Advanced Research Projects Agency's (DARPA) operations other than war/law enforcement (OOTW/LE). Additionally, this technology has numerous civilian law enforcement applications that are being investigated under the National Institute of Justice's (NIJ) Concealed Weapons Detection program. This paper discusses the wide variety of sensors that might be employed in support of a typical scenario, the strengths and weaknesses of each of the sensors relative to the given scenario, and how CWD breadboards will be tested to determine the optimal CWD application. It rapidly becomes apparent that no single sensor will completely satisfy the CWD mission necessitating the fusion of two or more of these sensors.

  2. Concealed neuroanatomy in Michelangelo's Separation of Light From Darkness in the Sistine Chapel.

    PubMed

    Suk, Ian; Tamargo, Rafael J

    2010-05-01

    Michelangelo Buonarroti (1475-1564) was a master anatomist as well as an artistic genius. He dissected cadavers numerous times and developed a profound understanding of human anatomy. From 1508 to 1512, Michelangelo painted the ceiling of the Sistine Chapel in Rome. His Sistine Chapel frescoes are considered one of the monumental achievements of Renaissance art. In the winter of 1511, Michelangelo entered the final stages of the Sistine Chapel project and painted 4 frescoes along the longitudinal apex of the vault, which completed a series of 9 central panels depicting scenes from the Book of Genesis. It is reported that Michelangelo concealed an image of the brain in the first of these last 4 panels, namely, the Creation of Adam. Here we present evidence that he concealed another neuronanatomic structure in the final panel of this series, the Separation of Light From Darkness, specifically a ventral view of the brainstem. The Separation of Light From Darkness is an important panel in the Sistine Chapel iconography because it depicts the beginning of Creation and is located directly above the altar. We propose that Michelangelo, a deeply religious man and an accomplished anatomist, intended to enhance the meaning of this iconographically critical panel and possibly document his anatomic accomplishments by concealing this sophisticated neuroanatomic rendering within the image of God. PMID:20404688

  3. Preventing Shoulder-Surfing Attack with the Concept of Concealing the Password Objects' Information

    PubMed Central

    Ho, Peng Foong; Kam, Yvonne Hwei-Syn; Wee, Mee Chin

    2014-01-01

    Traditionally, picture-based password systems employ password objects (pictures/icons/symbols) as input during an authentication session, thus making them vulnerable to “shoulder-surfing” attack because the visual interface by function is easily observed by others. Recent software-based approaches attempt to minimize this threat by requiring users to enter their passwords indirectly by performing certain mental tasks to derive the indirect password, thus concealing the user's actual password. However, weaknesses in the positioning of distracter and password objects introduce usability and security issues. In this paper, a new method, which conceals information about the password objects as much as possible, is proposed. Besides concealing the password objects and the number of password objects, the proposed method allows both password and distracter objects to be used as the challenge set's input. The correctly entered password appears to be random and can only be derived with the knowledge of the full set of password objects. Therefore, it would be difficult for a shoulder-surfing adversary to identify the user's actual password. Simulation results indicate that the correct input object and its location are random for each challenge set, thus preventing frequency of occurrence analysis attack. User study results show that the proposed method is able to prevent shoulder-surfing attack. PMID:24991649

  4. Three-Dimensional Millimeter-wave Imaging for Concealed Weapon Detection

    SciTech Connect

    Sheen, David M. ); McMakin, Douglas L. ); Hall, Thomas E. )

    2000-12-01

    Millimeter-wave imaging techniques and systems have been developed at the Pacific Northwest National Laboratory (PNNL) for the detection of concealed weapons and contraband at airports and other secure locations. These techniques were derived from microwave holography techniques which utilize phase and amplitude information recorded over a two-dimensional aperture to reconstruct a focused image of the target. Millimeter-wave imaging is well suited to the detection of concealed weapons or other contraband carried on personnel since millimeter-waves are non-ionizing, readily penetrate common clothing material, and are reflected from the human body and any concealed items. In this paper, a wide-bandwidth, three-dimensional, holographic microwave imaging technique is described. Practical weapon detection systems for airport, or other high-throughput applications, require high-speed scanning on the order of 3 to 10 seconds. To achieve this goal, a prototype imaging system utilizing a 2 7-33 GHz linear sequentially switched array and a high-speed linear scanner has been developed and tested. This system is described in detail along with numerous imaging results.

  5. Image fusion based on millimeter-wave for concealed weapon detection

    NASA Astrophysics Data System (ADS)

    Zhu, Weiwen; Zhao, Yuejin; Deng, Chao; Zhang, Cunlin; Zhang, Yalin; Zhang, Jingshui

    2010-11-01

    This paper describes a novel multi sensors image fusion technology which is presented for concealed weapon detection (CWD). It is known to all, because of the good transparency of the clothes at millimeter wave band, a millimeter wave radiometer can be used to image and distinguish concealed contraband beneath clothes, for example guns, knives, detonator and so on. As a result, we adopt the passive millimeter wave (PMMW) imaging technology for airport security. However, in consideration of the wavelength of millimeter wave and the single channel mechanical scanning, the millimeter wave image has law optical resolution, which can't meet the need of practical application. Therefore, visible image (VI), which has higher resolution, is proposed for the image fusion with the millimeter wave image to enhance the readability. Before the image fusion, a novel image pre-processing which specifics to the fusion of millimeter wave imaging and visible image is adopted. And in the process of image fusion, multi resolution analysis (MRA) based on Wavelet Transform (WT) is adopted. In this way, the experiment result shows that this method has advantages in concealed weapon detection and has practical significance.

  6. Preventing shoulder-surfing attack with the concept of concealing the password objects' information.

    PubMed

    Ho, Peng Foong; Kam, Yvonne Hwei-Syn; Wee, Mee Chin; Chong, Yu Nam; Por, Lip Yee

    2014-01-01

    Traditionally, picture-based password systems employ password objects (pictures/icons/symbols) as input during an authentication session, thus making them vulnerable to "shoulder-surfing" attack because the visual interface by function is easily observed by others. Recent software-based approaches attempt to minimize this threat by requiring users to enter their passwords indirectly by performing certain mental tasks to derive the indirect password, thus concealing the user's actual password. However, weaknesses in the positioning of distracter and password objects introduce usability and security issues. In this paper, a new method, which conceals information about the password objects as much as possible, is proposed. Besides concealing the password objects and the number of password objects, the proposed method allows both password and distracter objects to be used as the challenge set's input. The correctly entered password appears to be random and can only be derived with the knowledge of the full set of password objects. Therefore, it would be difficult for a shoulder-surfing adversary to identify the user's actual password. Simulation results indicate that the correct input object and its location are random for each challenge set, thus preventing frequency of occurrence analysis attack. User study results show that the proposed method is able to prevent shoulder-surfing attack. PMID:24991649

  7. Stepped-frequency CW radar for concealed weapon detection and through-the-wall surveillance

    NASA Astrophysics Data System (ADS)

    Hunt, Allen R.; Hogg, R. Douglas

    2002-08-01

    Both concealed weapons detection and through the wall surveillance are significant problems for both law enforcement and military personnel. While on the surface it would appear that these two problems are unrelated technologically, they do, in fact, share some common ground. A concealed weapon acts as resonant object, exhibiting electromagnetic resonance peaks at frequencies characteristic of the weapon's major dimensions. For handguns the frequency range of interest lies approximately between 450 MHz and 2 GHz. As it turns out, this is also a region over which many common building materials are largely transparent. As part of grant 97-IJ-CX-K013 from the National Institute of Justice, AKELA, Inc. has developed a stepped-frequency, CW radar that covers this frequency range. The radar is digitally synthesized and controlled and has a range resolution of approximately 4'. Digital waveform control gives the radar the ability to avoid interference with other electronic devices, to tailor data collection for signal processing requirements, and to change its sweep time in response to operational requirements. AKELA has developed a brassboard concealed weapons detector that uses this radar. A through the wall imaging system that uses the radar is currently in development under AFRL Contract F30602-00-C-0205.

  8. On the sensitivity of terahertz gyrotron based systems for remote detection of concealed radioactive materials

    NASA Astrophysics Data System (ADS)

    Nusinovich, G. S.; Sprangle, P.; Semenov, V. E.; Dorozhkina, D. S.; Glyavin, M. Yu

    2012-06-01

    This paper analyzes some features of systems intended to remotely detect concealed radioactive materials by using a focused THz radiation. This concept is based on possibility to focus high-power THz radiation in a small spot where the wave field exceeds the breakdown threshold. However, in the absence of any sources of ionization, the probability to have in this breakdown-prone volume any seed electrons is very low. Thus, high breakdown rate in a series of THz pulses will indicate the presence of concealed radioactive materials in the vicinity of a focused wave beam. The goal of the present paper is to determine by using the statistical theory THz pulse duration required for reliable initiation of the discharge. Then, the detectable mass of the radioactive material is determined as the function of distance and of the THz wave power and pulse duration. Lastly, possible benefits from using pulse compressors, which shorten the pulse duration but increase the wave power and, hence, the breakdown-prone volume, are analyzed. It is shown that the use of pulse compressors can significantly improve the sensitivity of THz gyrotron based systems for remote detection of concealed radioactive materials.

  9. Active wideband 350GHz imaging system for concealed-weapon detection

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.; McMakin, Douglas L.; Hatchell, Brian K.; Valdez, Patrick L. J.

    2009-05-01

    A prototype active wideband 350 GHz imaging system has been developed to address the urgent need for standoff concealed-weapon detection. This system is based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed conical scanner. This system is able to quickly scan personnel for concealed weapons. Additionally, due to the wideband operation, this system provides accurate ranging information, and the images obtained are fully three-dimensional. Waves in the microwave, millimeter-wave, and terahertz (3 GHz to 1 THz) frequency bands are able to penetrate many optical obscurants, and can be used to form the basis of high-resolution imaging systems. Waves in the sub-millimeter-wave band (300 GHz to 1 THz) are particularly interesting for standoff concealed-weapon detection at ranges of 5 - 20+ meters, due to their unique combination of high resolution and clothing penetration. The Pacific Northwest National Laboratory (PNNL) has previously developed portal screening systems that operate at the lower end of the millimeter-wave frequency range around 30 GHz. These systems are well suited for screening within portals; however, increasing the range of these systems would dramatically reduce the resolution due to diffraction at their relatively long wavelength. In this paper, the standoff 350 GHz imaging system is described in detail and numerous imaging results are presented.

  10. Fixations and eye-blinks allow for detecting concealed crime related memories.

    PubMed

    Peth, Judith; Kim, Johann S C; Gamer, Matthias

    2013-04-01

    The Concealed Information Test (CIT) is a method of forensic psychophysiology that allows for revealing concealed crime related knowledge. Such detection is usually based on autonomic responses but there is a huge interest in other measures that can be acquired unobtrusively. Eye movements and blinks might be such measures but their validity is unclear. Using a mock crime procedure with a manipulation of the arousal during the crime as well as the delay between crime and CIT, we tested whether eye tracking measures allow for detecting concealed knowledge. Guilty participants showed fewer but longer fixations on central crime details and this effect was even present after stimulus offset and accompanied by a reduced blink rate. These ocular measures were partly sensitive for induction of emotional arousal and time of testing. Validity estimates were moderate but indicate that a significant differentiation between guilty and innocent subjects is possible. Future research should further investigate validity differences between gaze measures during a CIT and explore the underlying mechanisms. PMID:23511446