• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1692-1695
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• 2015

최근 IoT 기기와 센서의 발전으로 다양한 서비스가 제안되고 있으며, 이를 제어하기 위한 인터페이스나 사용자 인터랙션에 대한 고민이 더욱 깊어지고 있다. 본 연구에서는 삼성의 Tizen 3.0 OS 버전을 기반으로 한 TV에서 IoT를 지원하는 인터페이스 디자인에 관해 설명하고 있다. 이러한 인터페이스를 ETG{EveryThing's Guide)라고 제안하였으며, IoT 시대의 허브 역할로서 사용자가 편안한 인터페이스를 사용할 수 있도록 하는 데 중점을 두었다. IoT 시대를 대비하는 TV나 모바일 기기의 형태는 사용자 중심의 간결하고 직관적인 인터페이스 디자인을 기반으로 하여야 한다. 따라서 구현 사례에서는 사용자에게 직접적으로 필요한 Thing들을 빠르게 접근하고 쉽게 제어할 수 있어야 한다는 점을 설계 시 고려하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.643-645
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• 2021

Minecraft Pi edition is a distinct version of Minecraft developed for Raspberry Pi and was mostly used as an educational instrument for upcoming programmers. In this paper, the basic method to control GPIO pin of Raspberry Pi 4 board using python 3 and Minecraft Pi software was implemented. The implemented scheme can be easily applicable to the area of educational platform and metaverse application if a plenty of python libraries embedded in raspberry pi and excellent gaming capability of Minecraft Pi software are efficiently merged to meet application-specific hardware and software requirements.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.65-75
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• 2005

Measurement of network traffic have shown that the self-similarity is a ubiquitous phenomenon spanning across diverse network environments. In previous work, we have explored the feasibility of exploiting the long-range correlation structure in a self-similar traffic for the congestion control. We have advanced the framework of the multiple time scale congestion control and showed its effectiveness at enhancing performance for the rate-based feedback control. Our contribution is threefold. First, we define a modular extension of the TCP-a function called with a simple interface-that applies to various flavours of the TCP-e.g., Tahoe, Reno, Vegas and show that it significantly improves performance. Second, we show that a multiple time scale TCP endows the underlying feedback control with proactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of the three traffic control dimensions-tracking ability, connection duration, and fairness-on performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.75-80
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• 2008

Measurement of network traffic have shown that the self-similarity is a ubiquitous phenomenon spanning across diverse network environments. In previous work, we have explored the feasibility of exploiting the long-range correlation structure in a self-similar traffic for the congestion control. We have advanced the framework of the multiple time scale congestion control and showed its effectiveness at enhancing performance for the rate-based feedback control. Our contribution is threefold. First, we define a modular extension of the TCP-a function called with a simple interface-that applies to various flavours of the TCP-e.g., Tahoe, Reno, Vegas and show that it significantly improves performance. Second, we show that a multiple time scale TCP endows the underlying feedback control with proactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of the three traffic control dimensions-tracking ability, connection duration, and fairness-on performance.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1256-1258
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• 2012

본 논문에서는 스마트 일렉트로 에코 시스템(Smart Electro-Eco System)의 일환으로 상황인지기반 가전 제품 원격 제어 및 관리 솔루션에 대해 기술한다. 본 솔루션 중 각 세대에 배치되는 홈 관리시스템은 n개의 특정기업 가전제품군과 원격 제어 애플리케이션, 홈 서버 시스템으로 구성된다. 또한 이러한 홈서버 시스템 m개로부터 데이터를 전송받아 분석 처리하는 빅데이터 서버 시스템이 있다. 홈 관리시스템에서는 가전제품에 부착된 센서의 센싱 데이터를 홈 서버 시스템으로 전송한다. 홈 서버 시스템에서는 실시간 가전제품 정보를 모니터링 및 원격 제어를 하고 설정된 상황이 인식되면 자동 제어 및 알림을 준다. 원격 제어 애플리케이션과 홈 서버 시스템의 통신으로 스마트 폰을 통해 가전제품 정보 및 원격 제어, NFC Tag를 이용한 원터치 제어를 할 수 있다. 빅데이터 서버 시스템에서는 대량의 데이터를 분석 및 통계를 내어 지역별, 시간대별 전류 소모량, 판매 실적 등을 측정하여 다음 버전에 나올 제품을 실제 데이터 통계로 인해 개선할 수 있다. 본 논문에서 기술하는 솔루션을 통하여 장소, 시간에 관계없이 홈을 스마트하게 관리할 수 있으며 가전제품 사용관련 빅데이터 처리를 통해 에너지의 효용성을 높일 수 있다.

• Journal of KIISE:Databases
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• v.29 no.3
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• pp.230-245
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• 2002

Database systems for real-time applications must satisfy timing constraints associated with transactions. Typically, a timing constraint is expressed in the form of a deadline and is represented as a priority to be used by schedulers. Recently, security has become another important issue in many real-time applications. In many systems, sensitive information is shared by multiple users with different levees of security clearance. As more advanced database systems are being used in applications that need to support timeliness while managing sensitive information, there is an urgent need to develop concurrency control protocols in transaction management that satisfy both timing and security requirements. In this paper, we propose two concurrence control protocols that ensure both security and real-time requirements. The proposed protocols are primarily based on multiversion locking. However, in order to satisfy timing constraint and security requirements, a new method, called the FREEZE, is proposed. In addition, we show that our protocols work correctly and they provide a higher degree of concurrency than existing multiversion protocols. We Present several examples to illustrate the behavior of our protocols, along with performance comparisons with other protocols. The simulation results show that the proposed protocols can achieve significant performance improvement.

• JOURNAL OF ELECTRICAL WORLD
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• s.268
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• pp.73-78
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• 1999

지구환경문제를 비롯하여 빌딩을 둘러싼 상황을 시시각각 변화하고 있다. 빌딩관리 시스템에 요구되는 니즈도 설비의 감시제어에서 효율적인 빌딩 운영관리에 대한 기여, 고신뢰 및 컴퓨터 네트웨크기술의 유효활용으로 변화를 보이고 있다. 미쓰비시전기의 ''MELBAS-AD''시리즈는 연 마루면적 1만$m^2$이상의 빌딩에 적합한 통합 빌딩관리 시스템으로 다음의 특징을 갖고 있으며 빌딩운영 관리와의 융합을 도모하고 있다. (1)철저한 분산처리, 2중화, 하드웨어의 고신뢰화, 독자적인 통신처리에 의한 고속화$\cdot$고신뢰화 (2)전기$\cdot$공조설비 등의 감시제어는 물론 방재$\cdot$방범$\cdot$승강기 설비의 감시제어를 통합. 또 복수 거점관리에 대응 (3)설비정보$\cdot$운전실적 정보의 일원적 관리, 설비보전 스케줄관리 지원에 의한 보전관리기능의강화 (4)미쓰비시전기 독자적인 열원 수요예측과 최적운전계획 알고리즘에 의한 에너지 관리기능의 강화 (5)화상의 디지털화, 화상처리에 의한 멀티미디어응용 감시기능의 강화 (6)브라우저를 사용한 그룸관리 및 원격에너지관리 등 인트라넷 응용기능의 강화 (7)퍼스컴이나 EWS와 전용 컨트롤러의 기기 내용연수 차이를 흡수하는 버전프리(Version free) 컨셉트 한편, 앞으로의 계획으로는 $\cdot$설비 인터페이스의 표준화와 고도화$\cdot$설비 데이터의 Seamless화 를 실시해 나갈 예정이다.

• Journal of KIISE:Information Networking
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• v.32 no.5
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• pp.583-592
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• 2005

An important factor influencing the robustness of the Internet is the end-to-end TCP congestion control. However, the congestion control scheme of TCP Reno, the most popular TCP version on the Internet, employs passive congestion indication. It makes the network congestion worse. Brakmo and Peterson proposed a congestion control algorithm, TCP Vegas, by modifying the congestion avoidance scheme of TCP Reno. Many studies indicate that Vegas is able to achieve better throughput and higher stability than Reno. But there are three unfairness problems in Vegas. These problems hinder the spread of Vegas in the current Internet. In this paper, in order to solve these unfairness problems, we propose a new congestion control algorithm called TCP NewVegas. The proposed NewVegas is able to solve these unfairness problems effectively by using the variation of the number of queued packets in a bottleneck router. To evaluate the proposed approach, we compare the performance among NewVegas, Reno and Vegas. Through the simulation, NewVegas is shown to be able to achieve throughput and better fairness than Vegas.

• The KIPS Transactions:PartD
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• v.8D no.1
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• pp.10-23
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• 2001

Transactions in real-time active databases have the notion of activeness where transactions are generated by external effects and another transaction. In this paper, we propose the multi version concurrency control algorithm for real-time active transactions. A real-time active transaction has a timing constraint in the form of a deadline until which the user wants to complete the transaction, and is characterized by triggering relationships which mean that association between a transaction that triggers the execution of another transaction and the triggered transaction. The triggering relationship is an important factor to resolve data conflicts among real-time active transactions. The proposed concurrency control mechanism resolves data conflicts by considering triggering relationships between conflicting transactions as well as priorities and precedence relationships. The conflict resolution mechanism considers association types of the triggering relationship such as abort and commit dependency, and then resolves data conflicts in favor of higher priority transactions. We also present the experimental results of our algorithm comparing other real-time active concurrency control algorithms.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.809-822
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• 2004

In this paper, we propose a concurrency control algorithm based on R-tree for spatial database management system. The previous proposed algorithms can't prevent problem that search operation is to be blocking during update operations. In case of multidimensional indexes like R-tree, locking of update operations may be locked to several nodes, and splitting of nodes have to lock a splitting node for a long time. Therefore search operations have to waiting a long time until update operations unlock. In this paper we propose new algorithms for lock-free search operation. First, we develop a new technique using a linked-list technique on the node. The linked-list enable lock-free search when search operations search a node. Next, we propose a new technique using a version technique. The version technique enable lock-free search on the node that update operations is to be splitting.