• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.1
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• pp.46-51
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• 2005

Intelligent Space(ISpace) is the space where many intelligent devices, such as computers and sensors, are distributed. According to the cooperation of many intelligent devices, the environment, it is very important that the system knows the location information to offer the useful services. In order to achieve these goals, we present a method for representing, tracking and human following by fusing distributed multiple vision systems in ISpace, with application to pedestrian tracking in a crowd. And the article presents the integration of color distributions into particle filtering. Particle filters provide a robust tracking framework under ambiguity conditions. We propose to track the moving objects by generating hypotheses not in the image plan but on the top-view reconstruction of the scene. Comparative results on real video sequences show the advantage of our method for multi-object tracking. Simulations are carried out to evaluate the proposed performance. Also, the method is applied to the intelligent environment and its performance is verified by the experiments.

• Journal of Communications and Networks
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• v.13 no.4
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• pp.306-312
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• 2011

In this paper, an efficient retransmission scheme using cooperation from neighboring nodes is investigated. In the cooperative retransmission scheme, an erroneous packet is retransmitted to the destination by cooperative nodes where distributed beamforming is used to accommodate multiple cooperating nodes. A Markov model is used to analyze throughput efficiency and average delay of the proposed retransmission scheme. It is shown that the analytical results are well matched with the simulated results and improved throughput and delay performance can be achieved as compared to the traditional retransmission scheme. The performance of the proposed cooperative retransmission is investigated in the multi-hop configuration via computer simulation. The transmit power for retransmission packet is also investigated and it can be significantly reduced by using a small feedback channel.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.9
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• pp.843-849
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• 2006

Intelligent Space defines an environment where many intelligent devices, such as computers and sensors, are distributed. As a result of the cooperation between smart devices, intelligence emerges from the environment. In such scheme, a crucial task is to obtain the global location of every device in order to of for the useful services. Some tracking systems often prepare the models of the objects in advance. It is difficult to adopt this model-based solution as the tracking system when many kinds of objects exist. In this paper the location is achieved with no prior model, using color properties as information source. Feature vectors of multiple objects using color histogram and tracking method are described. The proposed method is applied to the intelligent environment and its performance is verified by the experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4554-4561
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• 2014

In recent years, several paradigms have been identified to simplify the design of fault-tolerant distributed applications in a conventional static system. Leader Election is among the most noticeable, particularly because it is closely related to group communication, which provides a powerful basis for implementing active replications among other uses. On the other hand, despite its usefulness, to our knowledge, no study has focused on this problem in a mobile computing environment. The aim of this paper was to propose an algorithm for the leader election protocol in a fixed station based wireless networks environment. The election algorithm is much more efficient than other election algorithms in terms of the fault tolerance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.6
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• pp.506-512
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• 2005

Load redistribution algorithm is a critical factor in computer system. In a receiver-initiated Toad redistribution algorithm, receiver(underloaded processor) continues to send unnecessary request messages for load transfer until a sender(overloaded processor) is found while the system load is light. Therefore, it yields many problems such as low cpu utilization and system throughput because of inefficient inter-processor communications until the receiver receives an accept message from the sender in this environment. This paper presents an approach based on genetic algorithm(GA) for dynamic load redistribution including self-adjustable in heterogeneous distributed systems. In this scheme the processors to which the requests are sent off are determined by the proposed GA to decrease unnecessary request messages.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2279-2284
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• 2011

In most of radial distribution systems, the overcurrent protection coordination is adopted for the protection of apparatus and the improvement of electrical power system reliability. The protection coordination structure in distribution substation is composed of several circuit breakers(CB) with distribution lines originating from one substation bus under one transformer, which trip for their fault current. But sufficient analysis is necessary for the capacity of CB's in distribution systems with several distribution generations(DG). In this paper, a protection coordination method not to exceed the traditional capacity of CB's was proposed and certified through simulation by the PSCAD-EMTDC S/W.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.232-239
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• 2007

There is an increasing concern to interconnect DG(Distributed Generation) units into a distribution system and operate and maintain the system power quality within a proper level to distribution companies, regional electricity utilities and industrial customers. Recently, this situation makes many experts estimate a next generation of distribution system which is composed of some micro-grids. But the proposed micro-grid is only mentioned as a small grid with some DG units, some power quality compensators, communication and control equipments. In this paper, a topology and an operation/control algorithm of the micro-grid which is able to supply the electricity with high reliability and quality, are proposed.

• Geomechanics and Engineering
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• v.5 no.3
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• pp.241-261
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• 2013

The bearing mechanism of pile during installation and loading process which controls the deformation and distribution of strain and stress in the soil surrounding pile tip is complex and full of much uncertainty. It is pointed out that particle crushing occurs in significant stress concentrated region such as the area surrounding pile tip. The solution to this problem requires the understanding and modeling of the mechanical behavior of granular soil under high pressures. This study aims to investigate the sand behavior around pile tip considering the characteristics of sand crushing. The numerical analysis of model pile loading test under different surcharge pressure with constitutive model for sand crushing is presented. This constitutive model is capable of predicting the dilatancy of soil from negative to positive under low confining pressure and only negative dilatancy under high confining pressure. The predicted relationships between the normalized bearing stress and normalized displacement are agreeable with the experimental results during the entire loading process. It is estimated from numerical results that the vertical stress beneath pile tip is up to 20 MPa which is large enough to cause sand to be crushed. The predicted distribution area of volumetric strain represents that the distributed area shaped wedge for volumetric contraction is beneath pile tip and distributed area for volumetric expansion is near the pile shaft. It is demonstrated that the finite element formulation incorporating a constitutive model for sand with crushing is capable of producing reasonable results for the pile loading problem.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.3
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• pp.528-534
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• 2007

As XML is becoming a standard for representation and exchange of abundant information on the Web, solutions for a secure and selective dissemination of XML data, known as SDI, are strongly demanded. Such trends are more outstanding especially in distributed heterogeneous environment such as Peer-to-Peer. Although many approaches have been proposed to provide secure and efficient SDI mechanisms, almost previous approaches have focused only on filtering with user profile and they adopt center-oriented administration approaches. It is therefore difficult to adapt them directly to the distributed Peer-to-Peer environments characterized by dynamic participation. In this paper, we develop a novel dissemination method, which makesuse of authorization policy and secret sharing scheme. It provides more secure, scalable means for XML dissemination on Peer-to-Peer networks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.182-189
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• 2010

This paper defines the quorum-based fault-tolerant mutual exclusion problem in a message-passing asynchronous system and determines a failure detector to solve the problem. This failure detector, which we call the modal failure detector star, and which we denote by $M^*$, is strictly weaker than the perfect failure detector P but strictly stronger than the eventually perfect failure detector ◇P. The paper shows that at any environment, the problem is solvable with $M^*$.