• Spatial Information Research
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• v.21 no.3
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• pp.11-19
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• 2013

Compared with traditional video monitoring systems that provide a video-recording function as a main service, an intelligent video monitoring system is capable of extracting/tracking objects and detecting events such as car accidents, traffic congestion, pedestrian detection, and so on. Thus, the object tracking is an essential function for various intelligent video monitoring and surveillance systems. In this paper, we propose a background and local histogram-based object tracking approach for intelligent video monitoring systems. For robust object tracking in a live situation, the result of optical flow and local histogram verification are combined with the result of background subtraction. In the proposed approach, local histogram verification allows the system to track target objects more reliably when the local histogram of LK position is not similar to the previous histogram. Experimental results are provided to show the proposed tracking algorithm is robust in object occlusion and scale change situation.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.1037-1040
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• 2003

본 논문에서는 LAN 상에서 유휴 PC 들을 연산에 활용하는 PC Cluster 시스템에 대해 연구하였다. 특히, PC 실습실에 있는 PC 들의 유휴시간(Idle time)대를 이용하여 Cluster 연산에 사용함으로써 별도의 전용 클러스터 시스템을 설치하기 위한 하드웨어 및 설치 공간이 필요로 하지 않는다는 장점을 갖는다. PC 실습실의 PC 들은 주간에는 주로 교육 및 실습에 사용되며 오후 6시부터 오전 9시까지의 실습에 사용되지 않는 유휴시간을 CPU-Intensive 한 작업들을 병렬로 수행하는 PC Cluster로 구성하여 저가격의 고성능 시스템을 구축할 수 있다. 그리고 특정 연산을 전담하는 노드들을 지정하고 이 노드들의 연산 결과를 인접한 다른 노드들에게 전달함으로써 연속적인 다음 연산을 적용할 수 있도록 파이프라인(Pipeline) 형태로 구성한다. 파이프라인 형태의 PC Cluster 에서 연산을 겹침(Overlapped)으로서 처리량(Throughput)을 높일 수 있다. LAN으로 연결된 PC 실습실의 PC 들은 인터넷상의 연산 자원들보다 안정되고 신뢰성이 있기 때문에 복잡한 보안 기법을 사용하지 않아도 된다. 또한 연산시간이 유휴시간으로 고정되어 있기 때문에 네트워크의 부하 및 노드의 부하를 고려하는 복잡한 부하균등화 기법이나 스케줄링 기법이 필요로 하지 않는다.

• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.1-8
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• 2001

Recently, prestressed concrete(PSC) bridge structures with many repetitive spans have been widely constructed using the segmental construction method in many countries. In these segmentally constructed PSC bridges, there exist many construction joints which is required coupling of tendons or overlapping of tendons to introduce continuous prestress through several spans of bridges. The purpose of this paper is to investigate in detail the complicated stress distributions around the tendon coupled joints in prestressed concrete girders. To this end, a comprehensive experimental program has been set up and a series of specimens have been tested to identify the effects of tendon coupling. The present study indicates that the longitudinal and transverse stress distributions of PSC girders with tendon couplers are quite different from those of PSC girders without tendon couplers. It is seen that the longitudinal compressive stresses introduced by prestressing are greatly reduced around coupled joints according to tendon coupling ratios. The large reduction of compressive stresses around the coupled joints may cause deleterious cracking problems in PSC girder bridges due to tensile stresses arising from live loads, shrinkage and temperature effects. The analysis results by finite element method correlate very well with test results observed complex strain distributions of tendon coupled members. It is expected that the results of this paper will provide a good basis for realistic design guideline around tendon coupled joints in PSC girder bridges.

• Spatial Information Research
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• v.19 no.5
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• pp.63-74
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• 2011

Recently, there has been much interest in the spatial query which energy-efficiently acquires sensor readings from sensor nodes inside specified geographical area of interests. The centralized approach which performs the spatial query at a server after acquiring all sensor readings, though simple, it incurs high wireless transmission cost in accessing all sensor nodes. In order to remove the high wireless transmission cost, various in-network spatial indexing schemes have been proposed. They have focused on reducing the transmission cost by performing distributed spatial filtering on sensor nodes. However, these in-network spatial indexing schemes have a problem which cannot optimize both the spatial filtering and the wireless routing among sensor nodes, because these schemes have been developed by simply applying the existing spatial indexing schemes into the in-network environment. Therefore, we propose a new distributed spatial indexing scheme of the GR-tree. The GR-tree which form s a MBR-based tree structure, can reduce the wireless transmission cost by optimizing both the efficient spatial filtering and the wireless routing. Finally, we compare the existing spatial indexing scheme through extensive experiments and clarify our approach's distinguished features.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.1
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• pp.71-77
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• 2018

The optical time domain reflectometer (OTDR) is the most widely used method to monitor problems with currently installed optical fibers. The OTDR is an instrument designed to test the FTTx network and evaluates the physical properties of the fiber, such as transmission loss and connection loss. It is important to improve the spatial resolution in order to accurately grasp the optical path problems by using the OTDR. When the pulse width is less than twice the distance between the two reflectors, the signals reflected from the two reflectors are reflected without overlap, so that the reflected signal can be distinguished. However, when the pulse width is larger than twice the distance between the two reflectors, so that the reflected signal can not be distinguished. In order to overcome these limitations, this paper proposed a method of improving spatial resolution by applying a super resolution algorithm. As a result of the simulation, the resolution is improved when the super resolution algorithm is applied, and the event interval can be analyzed more precisely.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.1
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• pp.1-9
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• 2003

In this paper, we propose a new method dispersing spatially C(Cyan), M(Magenta), Y(Yellow) instead of K(black) in the bright region. The overlapping of black dots decreases brightness in the dark region, and black dots are very sensitive to human visual system in the bright region. Therefore, to avoid this problem, bright and dark gray region in the color image is considered in the proposed approach. A new method which uses CMY simultaneously in single mask is proposed, and CMY dots are used dispersing spatially for the bright region instead of black dot by this method. And tone curve connection is used to consider the gray level of dark region. In previous method, BNM (Blue Noise Mask) has high granularity and a narrow dynamic range. But the proposed method has the low granularity, wide dynamic range, and high contrast properties. Because the proposed method uses three times dots spatially in the different position than a conventional BNM, it can express more spatial information and a similar gray level compared with BNM.

• Korean Journal of Materials Research
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• v.22 no.8
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• pp.403-408
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• 2012

A sample of ultra low carbon IF steel was processed by six-layer stack accumulative roll-bonding (ARB) and annealed. The ARB was conducted at ambient temperature after deforming the as-received material to a thickness of 0.5 mm by 50% cold rolling. The ARB was performed for a six-layer stacked, i.e. a 3 mm thick sheet, up to 3 cycles (an equivalent strain of ~7.0). In each ARB cycle, the stacked sheets were, first, deformed to 1.5 mm thickness by 50% rolling and then reduced to 0.5 mm thickness, as the starting thickness, by multi-pass rolling without lubrication. The specimen after 3 cycles was then annealed for 0.5 h at various temperatures ranging from 673 to 973 K. The microstructural evolution with the annealing temperature for the 3-cycle ARB processed IF steel was investigated in detail by transmission electron microscopy observation. The ARB processed IF steel exhibited mainly a dislocation cell lamella structure with relatively high dislocation density in which the subgrains were partially observed. The selected area diffraction (SAD) patterns suggested that the misorientation between neighboring cells or subgrains was very small. The thickness of the grains increased in a gradual way up to 873 K, but above 898 K it increased drastically. As a result, the grains came to have an equiaxed morphology at 898 K, in which the width and the thickness of the grains were almost identical. The grain growth occurred actively at temperatures above 923 K.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.1
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• pp.51-59
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• 1999

In this paper we propose the technique for tracking players and a ball and for obtaining players' ground traces using image mosaic in general soccer sequences. Here, general soccer sequences mean the case that there is no extreme zoom-in or zoom-out of TV camera. Obtaining player's ground traces requires that the following three main problems be solved. There main problems: (1) ground field extraction (2) player and ball tracking and team indentification (3) player positioning. The region of ground field is extracted on the basis of color information. Players are tracked by template matching and Kalman filtering. Occlusion reasoning between overlapped players in done by color histogram back-projection. To find the location of a player, a ground model is constructed and transformation between the input images and the field model is computed using four or more feature points. But, when feature points extracted are insufficient, image-based mosaic technique is applied. By this image-to-model transformation, the traces of players on the ground model can be determined. We tested our method on real TV soccer sequence and the experimental results are given.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.9
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• pp.243-250
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• 2021

Recently, with the development of cloud computing, interest in database outsourcing is increasing. However, when the database is outsourced, there is a problem in that the information of the data owner is exposed to internal and external attackers. Therefore, in this paper, we propose a parallel range query processing algorithm that supports privacy protection. The proposed algorithm uses the Paillier encryption system to support data protection, query protection, and access pattern protection. To reduce the operation cost of a checking protocol (SRO) for overlapping regions in the existing algorithm, the efficiency of the SRO protocol is improved through a garbled circuit. The proposed parallel range query processing algorithm is largely composed of two steps. It consists of a parallel kd-tree search step that searches the kd-tree in parallel and safely extracts the data of the leaf node including the query, and a parallel data search step through multiple threads for retrieving the data included in the query area. On the other hand, the proposed algorithm provides high query processing performance through parallelization of secure protocols and index search. We show that the performance of the proposed parallel range query processing algorithm increases in proportion to the number of threads and the proposed algorithm shows performance improvement by about 5 times compared with the existing algorithm.