• International Journal of Control, Automation, and Systems
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• 제6권3호
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• pp.351-363
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• 2008

This paper is concerned with tasking and guidance of networked airborne sensors to achieve fault-tolerant sensing. The sensors are coordinated to locate hostile transmitters by intercepting and processing their signals. Faults occur when some sensor-carrying vehicles engaged in target location missions are lost. Faults effectively change the network architecture and therefore degrade the network performance. The first objective of the paper is to optimally allocate a finite number of sensors to targets to maximize the network life and availability. To that end allocation policies are solved from relevant Markov decision problems. The sensors allocated to a target must continue to adjust their trajectories until the estimate of the target location reaches a prescribed accuracy. The second objective of the paper is to establish a criterion for vehicle guidance for which fault-tolerant sensing is achieved by incorporating the knowledge of vehicle loss probability, and by allowing network reconfiguration in the event of loss of vehicles. Superior sensing performance in terms of location accuracy is demonstrated under the established criterion.

• 융합신호처리학회논문지
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• 제13권3호
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• pp.130-135
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• 2012

본 논문에서는 영상에서 반복적인 가우시안 커널을 사용하여 소형 표적의 크기와 위치를 검출하는 방법을 제안한다. 소형 표적의 크기와 위치를 검출하는 방법은 우선 페이싯 모델을 원 영상에 적용하여 국부 극대 값을 검출하고 $3{\times}3$ 가우시안 커널을 반복적으로 사용한다. 이때 반복횟수에 따른 국부 극대값 $D_2$를 비교하여 이에 따른 소형 표적의 크기를 결정한다. 또한 계산의 복잡성을 줄이기 위하여 커널을 반복적으로 사용할 때 가우시안 피라미드를 사용하였다. 실험에서는 소형 표적의 크기와 위치가 반복 횟수에 따라 정확히 검출되는 것을 확인하였고 기존의 방법에 비하여 처리속도가 개선된 것을 확인하였다.

• 대한인간공학회지
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• 제29권6호
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• pp.861-868
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• 2010

This study explored an extended three-dimensional Fitts' law that is more suited for the pointing task than the conventional Fitts' law. The experiments were conducted under the manipulation of the distance to the target, size of the target, and direction of the target's location that can be described by two angles, $\theta1$ and $\theta2$. Considering the starting point as the center of coordinates, $\theta1$ is the angle between the positive z-axis and the target location and $\theta2$ is the angle between the positive y-axis and the projected target location on the x-y plane. From the experimental results, we confirmed that all four variables significantly affect the movement time. As we extended the index of difficulty of the conventional Fitts' model by incorporating $\theta1$ and $\theta2$, we established an extended Fitts' model that showed better accordance with the empirical data than the conventional Fitts' model and 3D Fitts' law of Murata and Iwase, in terms of the $r^2$ and the standard error of the residual between the measured movement time and the predicted value.

• 융합신호처리학회논문지
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• 제12권2호
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• pp.76-82
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• 2011

본 논문은 다중 해상도 영상에서 3차 페이싯 모델을 이용하여 적외선 영상의 원거리에 위치하고 있는 초소형 표적의 위치와 크기를 검출하기 위한 방법을 제안한다. 먼저, 원 영상을 점차 축소하여 여려 단계의 다중 해상도의 영상들로 구성한다. 각 단계에서의 다중 해상도 영상들에 대해 페이싯 모델과 국부 극대 조건을 적용하여 초소형 표적의 위치를 검출한다. 다중 해상도 영상에서 각 페이싯 모델의 국부 극대값을 의미하는 $D_2$값 중 최대 크기를 가지는 위치를 표적의 위치라고 평가한다. 이 경우 각 단계의 다중 해상도 영상들에 대해 크기가 다른 표적의 검출이 가능하게 된다. 본 논문에서 제안한 초소형 표적 검출 방법은 초소형 표적이 있는 다양한 적외선 영상에서 실험하였다. 기존의 페이싯 모델을 이용한 방법에서는 하나의 마스크만 적용시킨 것에 반해 제안된 방법은 하나의 마스크를 다중 해상도 영상에서 적용하였다. 고정된 마스크를 다중 해상도 영상에 적용함으로써 마스크의 크기를 달리하는 효과를 확인하였고 그에 따라 검출하는 표적의 크기도 다름을 확인하였다. 이를 이용해서 표적의 위치뿐만 아니라 크기도 검출할 수 있음을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제3권1호
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• pp.108-118
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• 2009

In this paper we develop an indoor location tracking system and its 3D tracking monitoring viewer, viz., 3D Navigation Viewer (3DNV). We focus on the integration of an indoor location tracking system with the Virtual Reality Modeling Language (VRML), to facilitate a representation of the user's spatial information in virtual indoor environments that is synchronized with the physical location environment. The developed indoor location tracking system employs beacons as active transmitters, and a listener as a passive receiver. The distance information calculated from the difference speeds of RF and Ultrasonic signals is exploited, to determine the user's physical location. This is essential in supporting third parties like doctors and caregivers in identifying the activities and status of a particular individual via 3DNV. 3DNV serves as a unified user interface for an indoor location tracking system, showing the viewpoint and position of the target in virtual indoor environments. It was implemented using VRML, to provide an actual real time visualization of the target's spatial information.

• 한국콘텐츠학회논문지
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• 제10권1호
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• pp.87-93
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• 2010

본 논문에서는 목표의 위치를 결정하기 위해 사용되는 삼각법을 개선한 위치추정 방법을 제안한다. 제안하는 방법은 세 원간의 교점들을 통해 목표의 위치를 추정한다. 이 방법을 통해 결정된 목표의 위치는 기존의 방법과 같이 관측지역 중심에서 높은 정밀도를 갖고 기존의 방법에서 큰 오차를 갖는 관측지점 주변에서도 높은 정밀도를 갖는다. 이 방법은 기존의 방법보다 최대오차에서 40.89%, 평균오차에서 40.30%가 줄었다.

• 산업기술연구
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• 제9권
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• pp.67-77
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• 1989

This study is concerned with the accuracy, the pattern of error with which subjects can interpolate the location of a pointer or a target between two graduation markers with various size on CRT display. Stimuli were graphic images on CRT with a linear, end-marked, ungraduated scales having a target for t base-line sizes. The location of a target is estimated in units over the range 1-99. Smallest error of estimates was at the near ends and middle of the base-line. The median error was less 2 units, modal error was 1, and most error(;99.6%) was within 10. Subjects had a more tendency to overestimate than to underestimate at the left-part of base-line in all siges, and an opposite tendency at the right-part. A proper size to minimize the interpolation error exists such that size 500. It is suggested that interpolation of fifths and even tenths will give a reguired accuracy for certain situations, and relative location and base-line size has a relevant attribute to interpolate.

• Journal of Information Processing Systems
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• 제16권3호
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• pp.639-647
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• 2020

In the vibration target localization algorithms based on time difference of arrival (TDOA), Fang algorithm is often used in practice because of its simple calculation. However, when the delay estimation error is large, the localization equation of Fang algorithm has no solution. In order to solve this problem, one dimensional search location algorithm based on TDOA is proposed in this paper. The concept of search is introduced in the algorithm. The distance d1 between any single sensor and the vibration target is considered as a search variable. The vibration target location is searched by changing the value of d1 in the two-dimensional plane. The experiment results show that the proposed algorithm is superior to traditional methods in localization accuracy.

• 한국컴퓨터정보학회논문지
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• 제22권7호
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• pp.47-54
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• 2017

Recently, correlation filter based trackers have shown excellent tracking performance and computational efficiency. In order to enhance tracking performance in the correlation filter based tracker, search area which is image patch for finding target must include target. In this paper, two methods to discriminatively represent target in the search area are proposed. Firstly, search area location is estimated using pyramidal Lucas-Kanade algorithm. By estimating search area location before filtering, fast motion target can be included in the search area. Secondly, we investigate multi-channel Local Edge Pattern(LEP) which is insensitive to illumination and noise variation. Qualitative and quantitative experiments are performed with eight dataset, which includes ground truth. In comparison with method without search area estimation, our approach retain tracking for the fast motion target. Additionally, the proposed multi-channel LEP improves discriminative performance compare to existing features.

• 한국IT서비스학회지
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• 제10권4호
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• pp.243-258
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• 2011

With increasing interest in ubiquitous computing technology, an infrastructure for the short-distance wireless communication has been extended socially, bringing spotlight to the security system using the image or location. In case of existing security system, there have been issues such as the occurrences of blind spots, difficulty in recognizing multiple objects and storing of the unspecified objects. In order to solve this issue, zone-based location-estimation search system for the image have been suggested as an alternative based on the real-time location determination technology combined with image. This paper intends to suggest the search service for the image zone-based location-estimation. For this, it proposed the location determination algorism using IEEE 802.15.4/ZigBee's RSSI and for real-time image service, the RTP/RTCP protocol was applied. In order to combine the location and image, at the event of the entry of the specified target, the record of the time for image and the time of occurrence of the event on a global time standard, it has devised a time stamp, applying XML based meta data formation method based on the media's feature data based in connection with the location based data for the events of the object. Using the proposed meta data, the service mode which can search for the image from the point in time when the entry of the specified target was proposed.