• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.11
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• pp.69-76
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• 2008

Safety-related messages are propagated in form of broadcasting among vehicles in vehicle safety communication. There is the broadcast storm problem in high density vehicle environments. To solve this problem, a distance-based broadcast scheme has been proposed. It causes a serious problem such as retransmission delay in low density vehicle environments since it requires additional defer time to rebroadcast messages. This paper proposes a distance and random-based broadcast scheme. The proposed scheme selects a random time from zero to the defer time that estimated depending on the distance between sending and receiving vehicles. Simulation results show that the proposed scheme requires shorter defer time and less rebroadcasting message than existing schemes.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.2
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• pp.163-176
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• 2010

The representative method to efficiently manage the organization's data is to avoid data duplication through the promotion of sharing and reusing existing data. The systematic structuring of existing data and efficient searching should be supported in order to promote the sharing and reusing of data. Without regard for these points, the data for the system development would be duplicated, which would deteriorate the quality of the data. Data taxonomy provides some methods that can enable the needed data elements to be searched quickly with a systematic order of managing data. This paper proposes that the Origin data taxonomy method can best maximize data sharing, reusing, and consolidation, and it can be used for Meta Data Registry (MDR) and Semantic Web efficiently. The Origin data taxonomy method constructs the data taxonomy structure built upon the intrinsic nature of data, so it can classify the data with independence from business classification. Also, it shows a deployment method for data elements used in various areas according to the Origin data taxonomy structure with a data taxonomic procedure that supports the proposed taxonomy. Based on this case study, the proposed data taxonomy and taxonomic procedure can be applied to real world data efficiently.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.595-607
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• 2004

Networks often evolve to provide a host with multiple access points to the Internet. In this paper, we propose a transport layer load distribution mechanism utilizing the multiple network interfaces simultaneously. We specifically propose an extension of Stream Control Transmission Protoco1 (SCTP) to have load sharing over multiple network interfaces. We named the particular service provided by the Proposed load sharing mechanism to be LS (Load Sharing) mode service. LS mode service is based on the following four key elements: (i) the separation of flow control and congestion control, (ii) congestion window based striping, (iii) redundant packet retransmission for fast packet loss recovery, (iv) a novel mechanism to keep track of the receiver window size with the SACKS even if they arrive out-of-order. Through simulations, it is shown that the proposed LS mode service can aggregate the bandwidth of multiple paths almost ideally despite of the disparity in their bandwidth. When a path with a delay of 100% greater is utilized as the second path, the throughput is enhanced about 20%.

• KIISE Transactions on Computing Practices
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• v.23 no.2
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• pp.128-133
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• 2017

In recent years, the number of systems for the analysis of large volumes of data is increasing. Hadoop, a representative big data system, stores and processes the large data in the distributed environment of multiple servers, where system-resource management is very important. The authors attempted to detect anomalies from the rapid changing of the log data that are collected from the multiple servers using simple but efficient anomaly-detection techniques. Accordingly, an Apache Hive storage architecture was designed to store the log data that were collected from the multiple servers in the Hadoop ecosystem. Also, three anomaly-detection techniques were designed based on the moving-average and 3-sigma concepts. It was finally confirmed that all three of the techniques detected the abnormal intervals correctly, while the weighted anomaly-detection technique is more precise than the basic techniques. These results show an excellent approach for the detection of log-data anomalies with the use of simple techniques in the Hadoop ecosystem.

• Journal of KIISE:Software and Applications
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• v.32 no.8
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• pp.795-807
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• 2005

The classical approaches for computing Live Variable Analysis(LVA) use iterative algorithms across the entire programs based on the Data Flow Analysis framework. In case of Zephyr compiler, average execution time of LVA takes $7\%$ of the compilation time for the benchmark programs. The classical LVA algorithm has many aspects for improvement. The iterative algorithm for LVA scans useless basic blocks and calculates large sets of variables repeatedly. We propose the improvement of Iterative algorithm for LVA based on used variables' upward movement. Our algorithm produces the same result as the previous iterative algorithm. It is based on use-def chain. Reordering of applying the flow equation in DFA reduces the number of visiting basic blocks and redundant flow equation executions, which improves overall processing time. Experimental results say that our algorithm ran reduce $36.4\%\;of\;LVA\;execution\;time\;and\;2.6\%$ of overall computation time in Zephyr compiler with benchmark programs.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.6
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• pp.78-86
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• 2003

When we transformed from Monochrome-data to Color-data in text mode, we used hardware-method to design the circuit which is convertible in real time. We saved color information in every screens that can make screen in Color Palette ROM and it is also generated 8bit. lower 4bit assign foreground color and upper 4bit can design to have background color. We have Address Reduction ROM to remove repeated address and reduce volume of Color Palette ROM to 1/16. Besides, we have many D-FF to save address, data and page information temporarily after that, we have management process 8 times through counter in real time. Finally, we chose either foreground color or background color in multiplex and established color information was sended to the color video controller. Thus, you can use it as a good interface when yow transfer many control devices with Monochrome display (ex, LCD Monitor) into devices with Color display.

• Journal of KIISE:Software and Applications
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• v.26 no.8
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• pp.1010-1017
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• 1999

불완전한 계획 영역 이론은 오류 영역(noisy domain)에서 하나의 상태에 상반된 연산자들이 적용되는 불일치성 문제를 야기할 수 있다. 이 문제를 해결하기 위해서 본 논문은 상태를 기술하기 위해 다치 논리를 도입하여 제어지식으로서의 부정적 선행조건을 학습하는 새로운 방법을 제안한다. 기계에는 알려지지 않은 이러한 제어지식이 인간에게는 반대개념으로 잠재적으로 사용되고 있다. 이러한 잠재된 개념을 학습하기 위해 본 논문은 반대 연산자들로 구성된 사이클을 영역이론으로부터 기계적으로 생성하고, 이 연산자들에 대한 실험을 통해 반대 리터럴(literal)들을 추출한다. 학습된 규칙은 불일치성을 방지하면서 동시에 중복된 선행조건을 제거하여 연산자를 단순화시킬 수 있다.Abstract An incomplete planning domain theory can cause an inconsistency problem in a noisy domain, allowing two opposite operators to be applied to a state. To solve the problem, we present a novel method to learn a negative precondition as control knowledge by introducing a three-valued logic for state description. However, even though the control knowledge is unknown to a machine, it is implicitly known as opposite concept to a human. To learn the implicit concept, we mechanically generate a cycle composed of opposite operators from a domain theory and extract opposite literals through experimenting the operators. A learned rule can simplify the operator by removing a redundant precondition while preventing inconsistency.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.2
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• pp.149-159
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• 2000

In this paper, we propose a new class of MIN (Multistage Interconnection Network) called SCMIN(ShortCut MIN) which can form a cheap and efficient packet switching interconnection network. SCMIN satisfies full access capability(FAC) and has multiple redundant paths between processor-memory pairs even though SCMIN is constructed with 2.5N-4 SEs which is far fewer SEs than that of MINs. SCMIN can be constructed suitable for localized communication by providing the shortcut path and multiple paths inside the processor-memory cluster which has frequent data communications. Therefore, SCMIN can be used as an attractive interconnection network for parallel applications with a localized communication pattern in shared-memory multiprocessor systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12C
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• pp.167-173
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• 2001

Colored thread algorithm suggested by Ohba is understood to be effective to prevent from establishing path in loop. 3 kinds of thread state, such as null, colored, transparent, defined in colored thread algorithm which makes difficult and complex to design actions of the thread events, is reconfigured and improved to a 4 states to make the finite state machines simple. The original colored thread algorithm fonds loops by receiving thread of a same color that was generated by the initiator itself and confirms the loops by hop count of unknown thread traversed again along the looped path. This method is modified as to use the same color instead of generating new colored thread for the looped path, leading to save the traversing time. And also redefined the events to make easy coupling with existing protocols.

• 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.