• Journal of the Institute of Electronics Engineers of Korea CI
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• v.37 no.6
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• pp.10-21
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• 2000

The Cellular Noninear Networks structure for Distance Transform(DT) and the robust optical flow detection algorithm based on the DT are proposed. For some applications of optical flows such as target tracking and camera ego-motion computation, correct optical flows at a few feature points are more useful than unreliable one at every pixel point. The proposed algorithm is for detecting the optical flows on the trajectories only of the feature points. The translation lengths and the directions of feature movements are detected on the trajectories of feature points on which Distance Transform Field is developed. The robustness caused from the use of the Distance Transform and the easiness of hardware implementation with local analog circuits are the properties of the proposed structure. To verify the performance of the proposed structure and the algorithm, simulation has been done about various images under different noisy environment.

• The KIPS Transactions:PartD
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• v.13D no.7 s.110
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• pp.879-888
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• 2006

Recently many researchers have focused on management of Historical trajectories of moving objects in Euclidean spaces due to numerous sizes of accumulated data over time. However, the movement of moving objects in real applications generally has some constraints, for example vehicles on roads can only travel along connected road networks. In this paper, we propose an indexing method for trajectories of moving objects on road networks in order to process the network-based spatiotemporal range query. Our method contains the connect information of road networks to use the network distance for query processing, deals with trajectories which are represented by road segments in road networks, and manages them using multiple R-trees assigned per each road segment. Furthermore, it has a structure to be able to share R-tree among several road segments in large road networks. Consequently, we show that our method takes about 30% less in node accesses for the network-based spatiotemporal range query processing than other methods based on the Euclidean distance by experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.2
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• pp.166-174
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• 2009

The liquid column trajectory and column breakup length characteristics have been experimentally studied in angled jets injected into subsonic crossflow. Pulsed shadowgraph photography and Planar Liquid Laser Induced Fluorescence measurements were used to determine the angled effects. And the main objectives of this research are to get a empirical formula of liquid column trajectory and breakup length with below the $90^{\circ}$ degree injection angle conditions, and were compared with previous results. It was also found that the empirical formula, which reversed injection conditions of air stream. As the result, This has been shown that liquid column trajectories and column breakup length were spatially dependent on various injection angle, normalized injector exit diameter, air-stream and fuel injection velocity. Furthermore, the empirical formula of liquid column trajectories and breakup length has been some different of drag coefficient results between normal angled injection and reversed injection in subsonic crossflow.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.931-936
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• 2000

A novel CPFDTD algorithm for modeling the smooth curved surfaces is presented. This scheme subdivides electric fields on the distorted grid into the extended contour field, the non-distorted field, and the quasi-available field to avoid the collinear borrowing approximation. Several preceding methods are applied to the I-plane sectoral horn antenna to get far-field patterns. The accuracy of the presented method is demonstrated by comparison with measured values.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.91-92
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• 2023

이 연구에서는 선박이 군집을 이뤄 항해하는 방법으로, 추종 선박이 리더 선박의 궤적을 따라 항해하는 추종 알고리즘을 구현하고, 성능 검증을 위해 소형 RC 모형 보트를 사용하여 해상 실험을 수행하였다. 이 알고리즘은 추종 선박이 리더 선박의 궤적을 추종점으로 저장하고, 추종점까지의 목표 침로를 계산하여 추종하는 방법이다. 목표 침로는 시선각 유도법칙을 통해 계산하였으며, 목표 침로를 추종하기 위해 PD 제어를 적용한 침로 제어기를 구현하였다. 또한, 전방 선박과의 충돌을 방지하기 위해 전방 선박과의 거리에 따라 속력을 제어하는 알고리즘을 구현하였다. 구현된 알고리즘을 검증하기 위해 해상 실험을 진행하였으며, 결과를 분석하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.958-961
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• 2008

본 논문은 옥내측위 결과에 지도정합 방법을 적용하는 실험 결과를 소개한다. 사용한 지도정합 방법은 측위 결과로 얻은 측정 궤적에 칼만필터를 적용하여 매끄러운 칼만필터궤적을 얻은 다음, 칼만필터궤적과 이산크레쉐거리가 가장 가까운 보행자 통로로 정합한다. 사용한 지도정합 방법의 효율성을 보이는 실험 결과도 소개한다.

• Journal of Korea Spatial Information System Society
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• v.10 no.1
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• pp.29-40
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• 2008

With the spread of mobile devices and advances in communication techknowledges, the needs of application which uses the movement patterns of moving objects in history trajectory data of moving objects gets Increasing. Especially, to design public transportation route or road network of the new city, we can use the similar patterns in the trajectories of moving objects that move on the spatial network such as road and railway. In this paper, we propose a spatio-temporal similar trajectory search algorithm for moving objects on road network. For this, we define a spatio-temporal similarity measure based on the real road network distance and propose a grid-based index structure for similar trajectory search. Finally, we analyze the performance of the proposed similar trajectory search algorithm in order to show its efficiency.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.77-78
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• 2023

As large logistics buildings have high floor heights and long spans, these buildings are designed as PC structures, and large cranes are used to lift PC members. PC erection planning can generally cause errors depending on the field engineer's experience. To solve this problem, a basic analysis method is needed to establish a systematic PC member erection plan. Crane work can be minimized if the trajectory is easily and quickly calculated according to the location of the crane and applied to the site. Therefore, the objective of this study is a basic study of crane trajectory distance calculation for sustainable PC members erection of large logistic building. In this study, a crawler crane commonly used for lifting PC members is limited. The trajectory distance for the PC erection plan was automatically calculated using the algorithm.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.4
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• pp.257-266
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• 2001

It was set up MCS and MS of ship's distance measuring system in land and ship respectively and ship's track including dropped and hove up anchor was tracked by mean of measurement for ship's position, relative bearing and distance from MCS to MS. Results analyzed for possibility of real time anchoring watch and effectiveness of measuring position are as follow; (1) The elapsed time from dropped anchor to hove up anchor is 4 minutes and the elapsed time to start recording ship's track after set up anchoring state is 10 minutes approximately. (2) Shape of hull's swing during anchoring is mostly 8 figue-like or rarely peanut-like shape. (3) Mean anchoring position during whole measuring time was shifted 49m north and 89m eastly. (4) Ship's track were moved counter-clockwise for $8.1^\circ$ range from relative bearing $186.1^\circ$ to $194.2^\circ$ ellipse-like tracks with the major axis 63m and the minor axis 53m. (5) High frequency of ship's position distribution was shown at relative bearing $187^\circ$ and distance 558m while low frequency was shown at relative bearing $194^\circ$ and distance 556m. (6) The designed ship's distance measuring system by PRTK-GPS was fit very well for anchoring watch as secured necessary area demanded for dragging anchor as well as anchoring by means of real time measurement both in distance and bearing.

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.337-346
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• 2006

In order to analyze the behavior of moving objects, a measure for determining the similarity of trajectories needs to be defined. Although research has been conducted that retrieved similar trajectories of moving objects in Euclidean space, very little research has been conducted on moving objects in the space defined by road networks. In terms of real applications, most moving objects are located in road network space rather than in Euclidean space. In similarity measure between trajectories, however, previous methods were based on Euclidean distance and only considered spatial similarity. In this paper, we define similarity measure based on POI and TOI in road network space. With this definition, we present methods to retrieve similar trajectories using spatio-temporal similarity between trajectories. We show clustering results for similar trajectories. Experimental results show that similar trajectories searched by each method and consistency rate between each method for the searched trajectories.