• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.642-648
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• 2006

In this paper, I have proposed a secure dynamic ID allocation protocol using mutual authentication on the RFID tag. Currently, there are many security protocols focused on the low-price RFID tag. The conventional low-price tags have limitation of computing power and rewritability of memory. The proposed secure dynamic ID allocation protocol targets to the high-performance RFID tags which have more powerful performance than conventional low-price tag by allocating a dynamic ID to RFID using mutual authentication based on symmetric encryption algorithm. This protocol can be used as a partial solution for ID tracing and forgery.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5A
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• pp.451-458
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• 2006

In this paper, we propose a novel scheduling algorithm for downlink transmission which utilizes scarce wireless resource efficiently in an Orthogonal Frequency Division Multiple Access/Time Division Duplex system. Scheduling schemes which exploit channel information between a Base Station and terminals have been proposed recently for improved performance. Time series analysis is used to estimate the channel state of mobile terminals. The predicted information is then used for prioritized scheduling of downlink transmissions for improved throughput, delay and jitter performance. Through simulation, we show that the total throughput and mean delay of the proposed scheduling algorithm are improved compared with those of the Proportional Fairness and Maximum Carrier to Interference Ratio schemes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.720-726
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• 2009

There are coexisting various kinds of data in the large scale database system, the maintenance problem of freshness of data is emerging important issue that provide correctness and usefulness information to users. Most solution of this problem depends on how execute effectively required refreshing query within timely time. In this paper, we propose the refreshing scheduling algorithm to retain the freshness of data and fairness of starvation of requested refresh queries. Our algorithm recompute a rate of goal refreshing a every period to assign execution time of requested refreshing query so that we can keep the freshness and fairness of data by using proposed algorithm. We implement the web sites to showing the results of refreshing process of dynamic and semi-dynamic and static data.

• Convergence Security Journal
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• v.8 no.1
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• pp.19-26
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• 2008

In wireless sensor networks, an adversary can launch the wormhole attacks, where a malicious node captures packets at one location and tunnels them to a colluding node, which retransmits them locally. The wormhole attacks are very dangerous against routing protocols since she might launch these attacks during neighbor discovery phase. A strategic placement of a wormhole can result in a significant breakdown in communication across the network. This paper presents a compromise-resilient tunneled packet filtering method for sensor networks. The proposed method can detect a tunneled message with hop count alteration by a comparison between the hop count of the message and one of the encrypted hop counts attached in the message. Since the proposed method limits the amount of security information assigned to each node, the impact of wormhole attacks using compromised nodes can be reduced.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.367-381
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• 2011

Reducing waste for the efficiency of production is becoming more important because of the rapidly changing market circumstances and the rising material and oil prices. The dispatching also has to consider the characteristic of production circumstance for the efficiency. The production circumstance has the non-identical parallel machines with rework rate since machines have different capabilities and deterioration levels in the real manufacturing field. This paper proposes a dispatching method, FTLR (Flow Time Loss Index with Rework Rate) for production efficiency. The goal of FTLR is to minimize flow time based on such production environments. FTLR predicts the flow time with rework rate. After assessing dominant position of expected flow time per each machine, FTLR performs dispatching to minimize flow time. Experiments compare various dispatch methods for evaluating FTLR with mean flow time, mean tardiness and max tardiness in queue.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.482-488
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• 2012

Desktop is offered to each individual in Educational environments of school or academy, as the users are increasing, the more Desktop is required for each person. Huge Desktop accession resulted in many problems including difficulty of management, Software and Hardware cost rising, cramped places, power consumption increasing and etc. To solve those problems, we focus into uprising technology solution, such as Multi Computer, Desktop Virtualization, and DaaS(Desktop as a Service). In this paper, existing problems that can dramatically improve the private cloud computing for desktop virtualization with the requirements of the system were analyzed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1177-1183
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• 2010

In this paper, a parallel bank of multiple adaptive unknown input observers approach suggested by D.Wang is applied to detect a single fault of control surface actuator and to estimate the actuator position of lock-in-place fault using a small fixed-wing UAV model with eight control surfaces. This paper shows that not only the fault diagnosis algorithm detects and estimates each faults of lock-in-place in 1 second by simulation but also it may be unavailable to isolate among two same-shaped rudders.

• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1234-1245
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• 1998

This paper presents a multiagent system, based on the blackboard architecture and its mechanism of coordination and communication, developed for the collaboration of distributed heterogeneous software systems. The system provides the environment for the collaboration among pre-existing heterogeneous subsystems within the context of multimedia distance education application. The meta-knowledge for each agent is isolated in the global controller and the control knowledge and the problem-solving knowledge are clearly separated within the system. As a result, the coordination problem that typically found in the conventional distributed problem solving systems are greatly enhanced and the reusability of the pre-developed systems are improved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3163-3169
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• 2009

To secure superiority in keen competition among ports and to satisfy demands of shippers and shipping companies who are a main customer of ports, logistics service should be improved. However, most of dissatisfaction for logistics service arises from frequent transportation changes of shippers and inaccuracy of cargo-working information offered from shipping companies and inaccuracy of cargo information carried in from carriers. Therefore, the study embodied BPR and yard management prototype system on the basis of the process of business flow in yard to settle the above problems. The study also checked that information of booking list in a yard-allocated plan could be applied to forming efficient collaborative supply networking in yard management by supplementing insufficient cargo.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.7-10
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• 2018

통합 메모리는 CPU 메모리와 GPU 메모리 간의 데이터 통신을 개발자에게 투명하게 내재적으로 수행하는 소프트웨어 런타임 환경으로 개발자에게 CPU 메모리와 GPU 메모리가 통합된 하나의 메모리로 보이게 해준다. 통합 메모리는 장점에도 불구하고 아직 널리 사용되지 못하고 있는데 그 이유는 내재적으로 수행되는 데이터 통신의 오버헤드가 큰 것으로 알려져 있기 때문이다. 하지만 이 데이터 통신이 구체적으로 어떻게 이루어지고 오버헤드는 어떻게 발생하는지 분석한 연구는 아직 존재하지 않는다. 우리는 NVIDIA 사의 최신 GPU 마이크로아키텍처 중 하나인 파스칼을 사용하는 GPU를 대상으로 하여, 통합 메모리를 사용할 시 데이터 통신이 이루어지는 조건과 GPU 응용의 수행시간에 데이터 통신이 끼치는 영향을 실험을 통해 분석한다. 실험 결과 통합 메모리의 오버헤드는 두 가지 원인 때문에 발생한다. 첫째, 통합 메모리를 사용하면 CPU 또는 GPU가 데이터에 접근할 때마다 이 데이터는 CPU 또는 GPU 메모리로 옮겨지고 옮겨진 데이터는 제거된다. 따라서 재사용할 데이터도 제거되어 추가적인 데이터 통신이 발생하고, 이 데이터 통신의 지연시간은 GPU 응용의 수행시간에 더해진다. 둘째, 통합 메모리를 사용하면 데이터 통신과 커널들이 서로 다른 스트림에 할당되어도 동시에 수행되지 못한다. 따라서 GPU 응용의 수행시간은 동시에 수행되던 데이터 통신과 커널의 수행시간만큼 증가한다.