• Proceedings of the Korea Society for Simulation Conference
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• 2001.05a
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• pp.144-147
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• 2001

본 논문은 시뮬레이터 소프트웨어의 개발, 문서화, 실시간 수행 및 시험 등을 용이하게 하는 시뮬레이션 환경을 위해 개발중인 시뮬레이션 환경을 소개하는 것을 목적으로 하고 있다. 개발중인 시뮬레이션 환경은 원자력교육원 2호기 시뮬레이터 노심모델을 기본 모델로 하고있으며, 현재 멈춤/실행 (Freeze/Run), 운전상태의 저장(Snapshot), 임의의 변수에 대한 동적인 변수값 도시(Display), 실시간 형상화 툴 등 몇 가지 기능은 이미 구현하여 실행중이며, 조속한 시일에 전체적인 통합 환경이 구축될 것으로 예상된다. 본 시스템의 구축으로 모든 시뮬레이션 모델 및 각종 펄프의 실시간 실행/빠른실행/느린실행 등의 개별 운전모드 시간조정도 가능해져 시뮬레이터 모델 이외에도 기존의 사용 프로그램의 통합 등 다양한 응용이 가능할 것으로 기대된다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.841-843
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• 2005

최근 64비트 CPU의 시장 출시가 활발해지고 있으며, 메모리 모듈 또한 대용화가 이루어지고 있다. 이에 대용량 메모리를 64비트 CPU 플랫폼에서 효과적으로 테스트하는 방법을 개발할 필요성이 대두되고 있다. 본 논문에서는 x86-64 기반 리눅스 2.6.11 커널에서 물리 메모리의 테스트 영역을 확장하는 기법을 제안한다. 제안된 기법에는 응용이나 커널에서 물리 메모리에 대한 직접 접근, 프로그램을 사용자가 원하는 물리 메모리로 배치, 프로그램의 동적 재배치 등의 방법을 통해 테스트 영역을 확장 한다. 현재 64 비트 CPU를 지원하는 OS는 리눅스와 윈도우즈 64비트 에디션 등이 있다. 기존 리눅스 커널을 그대로 사용하였을 때 프로그램 등이 이미 사용 중인 물리 메모리에 대해서는 메모리 테스트를 수행 할 수 없었으나, 각 프로그램들을 물리 메모리에서 재배치하여, 원하는 곳의 메모리를 테스트 할 수 있도록 커널 수정을 통하여 구현하였다.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.131-140
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• 2011

Smart packet agent is an application that is proposed to provide routing protocol and service module in ubiquitous network environment. However, it uses multi-hop broadcast, thus it causes increasing network traffic, low-speed data transmission, and the unnecessary joining nodes. In this paper, a transmit technique that uses unicast-based multi-hop to have lower network traffic and faster transmission time than the multi-hop broadcast technique. In our scheme, u-Zone Master establishes temporary routing paths by calculating moving nodes' hop-counter. Therefore, it reduces smart packet agent's network traffic and retransmission rate. Besides, this paper proposed an UDP transmission that bases on sliding window. Hence, the Stop & Wait transmission speed is improved. The results, which are taken by analyzing performance prove that the proposed scheme has better performance.

• Journal of Korea Multimedia Society
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• v.8 no.9
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• pp.1163-1176
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• 2005

The Web is the largest distributed information space but, the individual's capacity to read and digest contents is essentially fixed. In these Web environments, mining traversal patterns is an important problem in Web mining with a host of application domains including system design and information services. Conventional traversal pattern mining systems use the inter-pages association in sessions with only a very restricted mechanism (based on vector or matrix) for generating frequent K-Pagesets. We extend a family of novel algorithms (termed WebPR - Web Page Recommend) for mining frequent traversal patterns and then pageset to recommend. We add a WebPR(A) algorithm into a family of WebPR algorithms, and propose a new winWebPR(T) algorithm introducing a window concept on WebPR(T). Including two extended algorithms, our experimentation with two real data sets, including LadyAsiana and KBS media server site, clearly validates that our method outperforms conventional methods.

• Journal of Internet Computing and Services
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• v.8 no.4
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• pp.41-49
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• 2007

Ethernet passive optical network(EPON) is the next-generation technology for supporting services of high-quality at low-cost. In the EPON, all optical network units(ONUs) have to share a limited uplink channel for upstream data. In order to satisfy bandwidth demands of users on high-capacity local access networks(LANs), the optical line terminal(OLT) efficiently divides and allocates time slots of uplink channel to all ONUs. We discuss previous schemes for dynamic bandwidth allocation(DBA), such as interleaved polling with adaptive cycle time(IPACT) and sliding cycle time(SLICT). In this paper, dynamic right sizing of maximum-windows(DRSM), as a novel bandwidth allocation service, is proposed for more effective and efficient time slot allocation of the uplink channel. DRSM which is based on past information of bandwidth allocated by OLT calculates maximum available bandwidth and dynamically alters the maximum window size for the next ONU. This scheme does not only exert every effort to meet bandwidth demands of ONUs with the possible scope, it also seeks fairness of bandwidth allocation among ONUs.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1335-1351
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• 2015

In order to effectively understand the perception of businesses and consumers, the Bank of Korea has released Economic Sentiment Index (ESI), a composite indicator of business survey index (BSI) and consumer survey index (CSI), since 2102. The usefulness of ESI has been widely recognized. However, there exists a margin for improvement in terms of its predictive power. In this study, we evaluated the usefulness of ESI and improved the ESI by complementing its defaults. Our results of empirical analysis proved that dynamic optimal weight navigation process using the sliding window method is very useful in determining the optimal weights of configurations item of ESI based on economic situation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8A
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• pp.613-619
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• 2003

Bluetooth is a communication technology enabling short-range devices to be wirelessly connected. A master and one or more slave devices are connected to form a piconet, and piconets are joined to form a scatternet. The units participating in two or more piconets in a scatternet, is called bridge or gateway nodes. In order to operate the scatternet efficiently, both piconet scheduling for the master and slaves of a piconet, and scatternet scheduling for the bridge nodes are playing important roles. In this paper, we propose a traffic-adaptive dynamic scatternet scheduling algorithm based on rendezvous points and rendezvous windows. The performance of the proposed algorithm is compared and analyzed with that of a static scheduling algorithm via simulations. Simulation results show that our algorithm can distribute wireless resources efficiently to bridge nodes depending on the traffic characteristics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9A
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• pp.905-915
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• 2007

This paper proposes a filter-based algorithm to adaptively adjust the contention window in IEEE 802.11 DCF. The proposed mechanism is focused on the general and realistic environments that have various conditions regarding to noise, media types and network load. For this flexible adaptation, Filter-based DCF(FDCF) takes a more realistic policy such as median filter concept in the image processing technologies. We can handle these various environments by adjusting the contention window size according to the result of filtering based on history-buffer. We can ignore temporarily and randomly occurred transmission failures due to noise errors and collisions in noisy environments. In addition, by changing the reference number and history-buffer size, FDCF can be extended as a general solution including previous proposed mechanism. We have confirmed that the proposed mechanism can achieve the better performance than those of previous researches in aspects of the throughput and the delay in the realistic environments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.103-111
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• 2023

This paper proposes a new data correction technique that transforms anomalies in time series data into normal values. With the recent development of IT technology, a vast amount of time-series data is being collected through sensors. However, due to sensor failures and abnormal environments, most of time-series data contain a lot of anomalies. If we build a predictive model using original data containing anomalies as it is, we cannot expect highly reliable predictive performance. Therefore, we utilizes the LSTM-GAN model to detect anomalies in the original time series data, and combines DTW (Dynamic Time Warping) and GAN techniques to replace the anomaly data with normal data in partitioned window units. The basic idea is to construct a GAN model serially by applying the statistical information of the window with normal distribution data adjacent to the window containing the detected anomalies to the DTW so as to generate normal time-series data. Through experiments using open NAB data, we empirically prove that our proposed method outperforms the conventional two correction methods.

• Journal of KIISE
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• v.42 no.5
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• pp.629-636
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• 2015

The types of errors corrected by a Korean spelling and grammar checker can be classified into isolated-term spelling errors and context-sensitive spelling errors (CSSE). CSSEs are difficult to detect and to correct, since they are correct words when examined alone. Thus, they can be corrected only by considering the semantic and syntactic relations to their context. CSSEs, which are frequently made even by expert wiriters, significantly affect the reliability of spelling and grammar checkers. An existing Korean spelling and grammar checker developed by P University (KSGC 4.5) adopts hand-made correction rules for correcting CSSEs. The KSGC 4.5 is designed to obtain very high precision, which results in an extremely low recall. Our overall goal of previous works was to improve the recall without considerably lowering the precision, by generalizing CSSE correction rules that mainly depend on linguistic knowledge. A variety of rule-based methods has been proposed in previous works, and the best performance showed 95.19% of average precision and 37.56% of recall. This study thus proposes a statistics based method using a conditional probability model with dynamic window sizes. in order to further improve the recall. The proposed method obtained 97.23% of average precision and 50.50% of recall.