• Title/Summary/Keyword: Target Location

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Information-Theoretic Approaches for Sensor Selection and Placement in Sensor Networks for Target Localization and Tracking

  • Wang Hanbiao;Yao Kung;Estrin Deborah
    • Journal of Communications and Networks
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    • v.7 no.4
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    • pp.438-449
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    • 2005
  • In this paper, we describes the information-theoretic approaches to sensor selection and sensor placement in sensor net­works for target localization and tracking. We have developed a sensor selection heuristic to activate the most informative candidate sensor for collaborative target localization and tracking. The fusion of the observation by the selected sensor with the prior target location distribution yields nearly the greatest reduction of the entropy of the expected posterior target location distribution. Our sensor selection heuristic is computationally less complex and thus more suitable to sensor networks with moderate computing power than the mutual information sensor selection criteria. We have also developed a method to compute the posterior target location distribution with the minimum entropy that could be achieved by the fusion of observations of the sensor network with a given deployment geometry. We have found that the covariance matrix of the posterior target location distribution with the minimum entropy is consistent with the Cramer-Rao lower bound (CRB) of the target location estimate. Using the minimum entropy of the posterior target location distribution, we have characterized the effect of the sensor placement geometry on the localization accuracy.

A Tracking System Using Location Prediction and Dynamic Threshold for Minimizing SMS Delivery

  • Lai, Yuan-Cheng;Lin, Jian-Wei;Yeh, Yi-Hsuan;Lai, Ching-Neng;Weng, Hui-Chuan
    • Journal of Communications and Networks
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    • v.15 no.1
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    • pp.54-60
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    • 2013
  • In this paper, a novel method called location-based delivery (LBD), which combines the short message service (SMS) and global position system (GPS), is proposed, and further, a realistic system for tracking a target's movement is developed. LBD reduces the number of short message transmissions while maintaining the location tracking accuracy within the acceptable range. The proposed approach, LBD, consists of three primary features: Short message format, location prediction, and dynamic threshold. The defined short message format is proprietary. Location prediction is performed by using the current location, moving speed, and bearing of the target to predict its next location. When the distance between the predicted location and the actual location exceeds a certain threshold, the target transmits a short message to the tracker to update its current location. The threshold is dynamically adjusted to maintain the location tracking accuracy and the number of short messages on the basis of the moving speed of the target. The experimental results show that LBD, indeed, outperforms other methods because it satisfactorily maintains the location tracking accuracy with relatively fewer messages.

Effect of orientation, interval size, target location on interpolation estimates on CRT display. (CRT 표시장치에서 내삽 추정치에 대한 방향, 크기, 위치의 효과)

  • 노재호
    • Journal of the Ergonomics Society of Korea
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    • v.9 no.1
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    • pp.35-42
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    • 1990
  • This study is concerned with the accuracy, of error with which subjects can interpolate the location of a target between two graduation markers with 4 orientations and 6 sizes CRT display. Stimuli were graphic images on CRT with a linear, end-markec, ungraduated scales having a target. The location of a target is estimated in units over te range 1-99. Smallest error of estimates was at the near ends and middle of the base-line. The median error was less than 2 units, modal error was 1, and the most error (; 99.7%) was within 10. A proper size to make an minimum error in interpolation exists such that size 400 pixels. Interpolation estimation is shown to be affected by the size, location and interaction (orientation x location, size x location). The accuracy, interpolation performance are discussed in relation to absolute error associated with visual performance.

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Location Information Extraction of An Air-to-Ground Target using Helmet Mounted Display Device (Helmet Mounted Display 장비를 사용한 공대지 표적의 위치정보 획득)

  • Bang, Kuk-Ryul;Ha, Seok-Wun
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.3
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    • pp.1-7
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    • 2011
  • An attack aircraft such as a fighter needs an accurate location information of a target for the exact air-to-air or air-to-ground attack. In this paper a method is proposed that generates a location information of an air-to-ground target just in use of HMD without the target tracking sensors such as the radar and the FLIR. HMD is an embedded device to induce the seeker header to indicate the direction of a pilot's head. As a simulation result, it is founded that the target location information is able to be generated with a high degree of precision by using of HMD as a passive sensor.

Location Estimation Enhancement Using Space-time Signal Processing in Wireless Sensor Networks: Non-coherent Detection

  • Oh, Chang-Heon
    • Journal of information and communication convergence engineering
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    • v.10 no.3
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    • pp.269-275
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    • 2012
  • In this paper, we proposed a novel location estimation algorithm based on the concept of space-time signature matching in a moving target environment. In contrast to previous fingerprint-based approaches that rely on received signal strength (RSS) information only, the proposed algorithm uses angle, delay, and RSS information from the received signal to form a signature, which in turn is utilized for location estimation. We evaluated the performance of the proposed algorithm in terms of the average probability of error and the average error distance as a function of target movement. Simulation results confirmed the effectiveness of the proposed algorithm for location estimation even in moving target environment.

Estimation of Person Height and 3D Location using Stereo Tracking System (스테레오 추적 시스템을 이용한 보행자 높이 및 3차원 위치 추정 기법)

  • Ko, Jung Hwan;Ahn, Sung Soo
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.8 no.2
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    • pp.95-104
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    • 2012
  • In this paper, an estimation of person height and 3D location of a moving person by using the pan/tilt-embedded stereo tracking system is suggested and implemented. In the proposed system, face coordinates of a target person is detected from the sequential input stereo image pairs by using the YCbCr color model and phase-type correlation methods and then, using this data as well as the geometric information of the stereo tracking system, distance to the target from the stereo camera and 3-dimensional location information of a target person are extracted. Basing on these extracted data the pan/tilt system embedded in the stereo camera is controlled to adaptively track a moving person and as a result, moving trajectory of a target person can be obtained. From some experiments using 780 frames of the sequential stereo image pairs, it is analyzed that standard deviation of the position displacement of the target in the horizontal and vertical directions after tracking is kept to be very low value of 1.5, 0.42 for 780 frames on average, and error ratio between the measured and computed 3D coordinate values of the target is also kept to be very low value of 0.5% on average. These good experimental results suggest a possibility of implementation of a new stereo target tracking system having a high degree of accuracy and a very fast response time with this proposed algorithm.

Small Target Detecting and Tracking Using Mean Shifter Guided Kalman Filter

  • Ye, Soo-Young;Joo, Jae-Heum;Nam, Ki-Gon
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.4
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    • pp.187-192
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    • 2013
  • Because of the importance of small target detection in infrared images, many studies have been carried out in this area. Using a Kalman filter and mean shift algorithm, this study proposes an algorithm to track multiple small moving targets even in cases of target disappearance and appearance in serial infrared images in an environment with many noises. Difference images, which highlight the background images estimated with a background estimation filter from the original images, have a relatively very bright value, which becomes a candidate target area. Multiple target tracking consists of a Kalman filter section (target position prediction) and candidate target classification section (target selection). The system removes error detection from the detection results of candidate targets in still images and associates targets in serial images. The final target detection locations were revised with the mean shift algorithm to have comparatively low tracking location errors and allow for continuous tracking with standard model updating. In the experiment with actual marine infrared serial images, the proposed system was compared with the Kalman filter method and mean shift algorithm. As a result, the proposed system recorded the lowest tracking location errors and ensured stable tracking with no tracking location diffusion.

Selection of Green-Roofs' Location to Improve Green-Network in Junggu, Seoul - Using a Bird as Target Species - (녹지네트워크의 기능향상을 위한 서울시 중구의 옥상녹화 입지 선정 - 조류를 목표종으로 활용하여 -)

  • Park, Jong-Hoon;Yang, Byoung-E
    • KIEAE Journal
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    • v.10 no.6
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    • pp.3-10
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    • 2010
  • The subject is to find green roofs' location as stepping stones in green-network in fine scale. The study site is Junggu, Seoul, which has core areas(Bukaksan and Namsan) and green areas(parks, etc.). Through literature review, the closer to core areas and green areas, target species reach green roof easier, and target species must be avifauna(flying species) and high class in food chain, because of possibility of reaching. So, Great Tits, inhabited in Namsan and urban bird, is target species. The location standard of green roofs, realized birds' reaching distance, consists of home range(horizontal range and vertical range) and roof-greening capable area. The green roofs' distribution of location was resulted through GIS analysis of feasible site finding, and classified with weight of score. In discussion, Namsan gives more effect to locate green roofs than Bukaksan does and selected buildings which are grouped in some parts need to be managed with group, green roof district.

An Effective TOA-based Localization Method with Adaptive Bias Computation

  • Go, Seung-Ryeol
    • Journal of IKEEE
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    • v.20 no.1
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    • pp.1-8
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    • 2016
  • In this paper, we propose an effective time-of-arrival (TOA)-based localization method with adaptive bias computation in indoor environments. The goal of the localization is to estimate an accurate target's location in wireless localization system. However, in indoor environments, non-line-of-sight (NLOS) errors block the signal propagation between target device and base station. The NLOS errors have significant effects on ranging between two devices for wireless localization. In TOA-based localization, finding the target's location inside the overlapped area in the TOA-circles is difficult. We present an effective localization method using compensated distance with adaptive bias computation. The proposed method is possible for the target's location to estimate an accurate location in the overlapped area using the measured distances with subtracted adaptive bias. Through localization experiments in indoor environments, estimation error is reduced comparing to the conventional localization methods.

The Influence of Different Objects and Target Locations of Dominant Hand on the Non-Dominant Hand Movement Kinematics in Bimanual Reaching (양손으로 물체 옮기기 과제 수행 시 우세손이 옮기는 물체의 종류와 목표점의 위치 변화가 비우세손의 팔뻗기 동작에 미치는 영향)

  • Kim, Min-Hee;Jeon, Hye-Seon
    • Physical Therapy Korea
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    • v.15 no.3
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    • pp.44-52
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    • 2008
  • The purpose of this study was to investigate the effects of different objects and target location of dominant hand on the non-dominant hand movement kinematics in a bimanual reaching task. Fifteen right-handed volunteers were asked to reach from same starting point to the different target point of right and left hand with grasping the objects of different size. Independent variables were 1) three different object types (small mug cup, name pen, and PET bottle), and 2) three different target locations (shorter distance, same distance, and longer distance than the non-dominant hand) of the dominant hand. Dependent variables were movement time (MT), movement distance (MD), movement mean velocity ($MV_{mean}$), and movement peak velocity ($MV_{peak}$) of the non-dominant hand. Repeated measures two-way analysis of variance (ANOVA) was used to test for differences in the non-dominant hand movement kinematics during bimanual reaching. The results of this study were as follows: 1) MT of the non-dominant hand was increased significantly when traveling with grasping the mug cup and reaching the far target location, and was decreased significantly when traveling with grasping the PET bottle and reaching the near target location of the dominant hand. 2) MD of the non-dominant hand was significantly increased during reaching the far target location, and significantly decreased during reaching the near target location with dominant hand. 3) $MV_{mean}$ of the non-dominant hand was increased significantly when traveling with grasping the PET bottle, and was decreased significantly when traveling with grasping the mug cup of the dominant hand. Therefore, it can be concluded that the changes of the ipsilateral hand movement have influence on coupling of the contralateral hand movement in bimanual reaching.

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