• Journal of KIISE:Databases
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• v.28 no.3
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• pp.484-493
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• 2001

As real-time database systems are extended to the distributed computing environment, the need to apply the existing real-time concurrency control schemes to the distributed computing environment has been made. In this paper we propose an efficient concurrency control scheme for distributed real-time database system. Our proposed scheme guarantees a transaction to commit at its maximum, reduces the restart of a transaction that is on the prepared commit phase, and minimizes the time of the lock holding. This is because it raises the priority of the transaction that is on the prepared commit phase in the distributed real-time computing environment. In addition, it reduces the waiting time of a transaction that owns borrowed data and improves the performance of the system, as a result of lending the data that the transaction with the raised priority holds. We compare the proposed scheme with DO2PL_PA(Distributed Optimistic Two-Phase Locking) and MIRROR(Managing Isolation in Replicated Real-time Object Repositories) protocol in terms of the arrival rate of transactions, the size of transactions, the write probability of transactions, and the replication degree of data in a firm-deadline real-time database system based on two-phase commit protocol. It is shown through the performance evaluation that our scheme outperforms the existing schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.6
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• pp.1137-1147
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• 1997

I propose a RZETA network consisted of switching elements(SEs) that have regular links and alternate links. A modified Zeta nework used for the RZETA network's regular links and a MIN used for its alternate links are generated using the graph theory. The RZETA network is driven from merging the formaer and latter MINs. A necessary and sufficient condition for modified Zeta network to be a nonblocking network is also presented. This condition is a ufficient condition for RZETA network with a faulty link or a faulty SE to be nonblocked. Performance of the RZETA network is analyzed by modification of the model of 2-dilated Banyan network and its performance is compared with existing redundant path networks, when packet arrival rate of each source is 1.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.7
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• pp.753-759
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• 2009

As many systems depend on electronics in an intelligent vehicle, concern for fault tolerance is growing rapidly. For example, a car with its braking controlled by electronics and no mechanical linkage from brake pedal to calipers of front tires(brake-by-wire system) should be fault tolerant because a failure can come without any warning and its effect is devastating. In general, fault tolerance is usually designed by placing redundant components that duplicate the functions of the original module. In this way a fault can be isolated, and safe operation is guaranteed by replacing the faulty module with its redundant and normal module within a predefined interval. In order to make in-vehicle network fault tolerant, this paper presents the concept and design methodology of an IEEE 1451 based dual CAN module. In addition, feasibility of the dual CAN network was evaluated by implementing the dual CAN module.

• Journal of Korea Spatial Information System Society
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• v.11 no.3
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• pp.47-49
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• 2009

In this paper, we proposed a new algorithm for determination of many-to-many corresponding pairs between block-polygon sets from the national topographical map and the cadastral map in Korea Land Information System, caused by different abstraction and generalization rules of the two maps. Our proposed algorithm starts from an assumption that a block-polygon for a N:M pair should significantly overlap at least one block polygon of the counterpart group, and determines N:M pairs using an iterative updating and searching with this overlapping analysis. This iteration process is terminated when the N:M corresponding pairs satisfy our predefined 1:1 corresponding condition.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.1
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• pp.41-46
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• 2005

A new multiple description selective coding is proposed to overcome noisy channels. Our algorithm adopts an embedded coding scheme, in which subband coefficients are encoded one bit plane at a time using a non-adaptive arithmetic encoder. According to the importance ratio for each region, we code interest regions with more passes than background in order to reconstruct interest regions with higher quality. To overcome channel errors, we adopt multiple description scheme which adds controlled amounts of redundancy to the original data during the compression process. Proposed algorithm achieves better qualify compared with other algorithms especially in the circumstances where very low bit rate coding is required and some regions are more important than other regions.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.54-63
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• 2013

In general, multiple hydraulic servo actuators are installed on one control surface of aero-dynamically highly loaded condition aircraft for redundancy management to satisfy flight control safety requirements. If motions of multiple actuators are not synchronized, control surface is deformed from its free stressed state. In result, force fight conditions are generated on each actuator due to restoration reaction force of deformed control surface. In addition, force fight is induced from severe initial rigging tolerance. Force fight condition of multiple actuators affects control accuracies and reduces operational life of actuators and control surface due to fatigue phenomenon. In this study, we designed controller using force feedback to reduce force fight of duplex servo actuation system.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.1-8
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• 2006

The Steer-By-Wire(SBW) system replaces complex mechanical linkages of the current steering system with electric motors, sensors, and electronic control units. However, the SBW system should guarantee its safety and reliability before commercialization, and therefore, a reliable and robust fault-tolerant technology has to be implemented. This paper proposes a fault-tolerant control algorithm for the SBW system. Based on careful analysis on propagation effects of sensor faults, a reliable fault-tolerant control strategy has been developed. The fault-tolerant controller consists of a fault detection part that monitors and detects faults in the steering wheel and road wheel sensors, and a reconfiguration part that switches to normal sensor signal based on fault detection information. It has been demonstrated by simulation that the proposed algorithm detects sensor faults accurately and enables reliable steering control under various dynamic fault situations.

• Journal of Space Technology and Applications
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• v.2 no.2
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• pp.137-145
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• 2022

Space development has been independently performed by space agencies in each country. This causes redundant development for individual function, resulting in waste of space resources. Accordingly, Interagency Operations Advisory Group (IOAG) was established for standardization with mutual agreement between international organizations, and space resources can be used efficiently between space agencies through cross-support. IOAG define Service Catalog#1, #2, and #3, according to the network layer. In this technical paper, the background and main contents of the IOAG Service Catalog, and the application plan for domestic space development will be discussed.

• Journal of Korea Fair Competition Federation
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• no.150
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• pp.14-29
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• 2010

비록 부정경쟁방지법의 제정 목적이 부정경쟁행위 등의 방지를 통하여 건전한 거래질서를 유지한다는 의미의 경쟁체제 확립에 있기는 하지만, 우리나라의 경우는 법 제정 당시와는 달리 사실상 산업스파이에 대한 영업비밀의 보호나 주지의 상표 영업표지의 보호와 같은 지적재산권의 보호 법률로서의 역할로 점차 변화하고 있고, 특히 부정경쟁방지법이 주지의 상표에 대한 출처의 혼동에 대한 규제뿐만이 아니라 별도로 저명상표의 희석화(稀釋化) 방지라는 법익, 이에 더 나아가 도메인 네임(Domain Name)의 선점과 원산지 및 품질의 오인(誤認) 야기행위, 주지 저명한 타인의 디자인(Design), 캐릭터(Character)와 같은 상품의 표지에 이르기까지 지적재산권과 관련된 보다 넓은 법익의 보호까지 수행하게 되면서 그 기능은 날로 강화되고 있는 상태이다. 이에 반하여 부정경쟁방지법상의 부정경쟁행위 자체에 대한 규제는 사실상 주지 저명한 타인의 상표나 상품표지의 식별력이나 출처표시기능 등의 보호라는 의미의 분쟁수준을 넘지 못하고 있어, '경쟁법'으로서의 역할은 상대적으로 미약해지고 있는 것 또한 현실이다. 또한, 공정거래법 제23조 제1항 제8호를 비롯하여 현행 공정거래법상의 불공정거래행위에 대한 규정체제를 살펴보면, 해석 여하에 따라서는 부정경쟁방지법상의 부정경쟁행위가 대부분 공정거래법상의 불공정거래행위의 범위 내로 포섭될 수도 있는 상황이기도 하다. 이에 양 법률의 성격과 역할, 앞으로 나아가야 할 방향을 고민하지 않을 수 없고, 이와 같은 논의는 발전적 입법론으로서의 가치를 갖는다. 물론 불공정거래행위(부정경쟁행위)에 대한 규제에 있어서 반드시 독일법체계에 따를 것인지 아니면 미국의 경우를 따를 것인지에 대한 선택 자체가 논리적으로 양립 불가능한 것은 아닐 것이지만 우리나라의 경우는 1980년 "독점규제 및 공정거래에 관한 법률"이 제정되는 과정에서 당시 부정경쟁방지법에 담겨 있던 기존의 부정경쟁행위에 대한 규정과 공정거래법상의 불공정거래행위와의 경합이나 중복문제는 마땅히 검토되었어야 했음에도 불구하고 공정 거래법의 제정과정에서 사실상 부정경쟁방지법의 존재 자체가 간과되어 오늘에 이르고 있다. 그동안 양 법률상의 규정 중복이나 충돌을 정식으로 문제 삼았던 바는 없었지만 '발전적 입법론' 이라는 차원에서 살펴 보면 부정경쟁방지법상의 부정경쟁행위에 대한 규제는 앞으로 공정거래법체계 내의 불공정거래행위로 포섭할 필요가 있고 이를 통하여 경쟁정책의 전문 전담기구로서 불공정거래행위에 대한 규제의 중심에 서 있는 공정거래위원회를 중심으로 효율적이고 통일적인 경쟁정책을 확립을 기대하여 볼 수 있을 것이다. 이 과정에서 공정거래법의 변화 또한 뒤따라야 하는데, 부정경쟁방지법상의 부정경쟁행위의 편입에 따라 불공정거래행위에 대한 규정 일부를 알맞게 다시 수정하는 것에 그치지 않고, 기존 부정경쟁방지법이 인정하고 있었던 사인간(私人間) 금지 또는 예방청구권 또한 공정거래법으로 그대로 편입되는 방향으로의 입법 개선이 이루어질 필요가 있으며, 그동안 '부정경쟁방지법의 공정거래법으로의 편입문제'와는 전혀 무관하게 공정거래법의 사적 구제 및 사소(私訴)의 활성화 차원의 논의로서 공정거래법상 사인간 금지청구권의 도입 여부가 검토되어 왔지만, 앞으로 이 문제는 부정경쟁방지법상 부정경쟁행위의 공정거래법체계 내로의 편입문제와 함께 이를 포함한 더욱 큰 논의로서 다시 적극적으로 검토될 필요가 있다고 본다. 이를 통하여 앞으로 부정경쟁방지법은 특허청을 중심으로 산업스파이에 대한 규제나 영업비밀의 보호와 기타 지적재산권의 보호에 온 힘을 다하고, 공정거래법은 공정거래위원회를 중심으로 불공정거래행위 (부정경쟁행위에 대한 보다 포괄적이고 통일적인 규제를 담당하여 '선택과 집중' 이라는 차원의 각 법률체계의 한 차원 높은 발전 또한 기대해 볼 수 있을 것으로 확신한다. 이러한 합의점을 시작으로 미시적인 다음 단계의 논의에 해당하는 사인간 금지청구권의 허용범위나 허용요건, 남용을 방지하기 위한 제도적 장치, 단체소송 등의 허용 여부 등의 논의도 함께 하여야 할 것이고, 이 과정에서 미국의 클레이튼법(Clayton Act)이나 가까운 일본의 입법례를 참고하여 우리의 실정에 맞는 규제의 틀을 마련함이 타당할 것이고, 이를 통하여 궁극적으로 그동안 공정거래법의 사적 집행의 활성화를 통한 경쟁질서의 확립의 강화라는 이상에 더욱 가까워질 수 있는 좋은 입법적 변화의 모습을 볼 수 있을 것이라 생각한다.

• Journal of KIISE:Information Networking
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• v.34 no.3
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• pp.218-225
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• 2007

As the research on home network technologies, sensor network technologies, and ubiquitous network technologies makes rapid progresses, wireless ad-hoc network have attracted a lot of attention. A wireless mobile ad-hoc network is a temporary network formed by a collection of wireless mobile nodes without the aid of any existing network infrastructure or centralized administration, and it is suitable for ubiquitous computing environments. In this paper, we suggest an extension scheme of a wireless mobile ad-hoc network based on limited multiple paths source routing protocol. This scheme reduces the overhead of route re-establishment and re-registration by maintaining link/node non-disjoint multiple paths between mobile hosts in a wireless mobile ad-hoc network or a mobile host in a wireless mobile ad-hoc network and a base station supporting fixed network services. By maintaining multiple paths, our scheme provides short end-to-end delay and is reliable extension scheme of a wireless mobile ad-hoc network to a fixed network. In this paper, our simulations show that our scheme outperforms existing schemes with regards to throughput and end-to-end delay. Also we show that our scheme outperforms multi-paths approach using disjoint routes with regards to routing overhead.