• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.8
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• pp.1111-1115
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• 2014

With the increasing interest of a demand side management using a Smart Grid infrastructure, the demand resources and energy usage data management becomes an important factor in energy industry. In addition, with the help of Advanced Measuring Infrastructure(AMI), energy usage data becomes a Big Data System. Therefore, it becomes difficult to store and manage the demand resources big data using a traditional relational database management system. Furthermore, not many researches have been done to analyze the big energy data collected using AMI. In this paper, we are proposing a Hadoop based Big Data system to manage the demand resources energy data and we will also show how the demand side management systems can be used to improve energy efficiency.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.706-708
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• 2005

시맨틱 웹의 등장으로 시맨틱 검색에 대한 관심이 높아졌다. 이에 본 논문에서는 시맨틱 웹 환경의 자원들을 이용하여 시맨틱 검색을 수행하는 검색방법을 제안한다. 기존의 SPARQL(Simple Protocol and RDF Query Language) 시맨틱 질의언어는 추론의 기능 없이 RDF(Resource Description Framework)에서 제공하는 SPO(subiect, predicate, object) 형태의 트리플 패턴 매치만을 제공한다. 본 논문의 시스템은 기존의 SPARQL질의 시스템에 시맨틱 추론기능을 추가하여 검색 결과에 효율성을 증가 시키는 것을 목적으로 한다. 본 논문에서의 시스템은 다음과 같은 특징을 갖는다. 첫째, 시맨틱 웹 환경의 온톨로지 구축을 위해서 W3C에서 온톨로지 언어로 표준화된 OWL(Web Ontology Language)를 사용하여 검색 환경을 구축한다. 둘째, 온톨로지와 메타데이터를 추론하여 시맨틱 검색을 유도하는 OWL추론기를 사용한다. 시맨틱 추론은 온롤로지의 공리(Axiom)을 충분히 활용하는 온톨로지기반 시맨틱 추론과 검색 도메인에 맞는 규칙을 활용하는 사용자 컨텍스트 기반의 시맨틱 추론으로 이루어진다. 셋째, 다양한 시맨틱 검색을 위해 W3C에서 제안되어 차세대 시맨틱 검색 질의언어로 연구중인 SPARQL을 사용한다. 이와 같은 특징은 시맨틱 검색 시스템이 시맨틱 웹 환경의 자원을 충분히 활용하는 결과를 가져온다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.211-214
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• 2014

Nowadays, manufacturing field are facing new challenges, through digital information and global integration, toward sophisticated production. This paper presents the system configuration and issues of current manufacturing execution system(MES), and describes major issues and solving elements to establish a MES system for cloud services. Also, it proposes business intelligence(BI) systems for building a manufacturing information system to have the optimized production flow and to respond appropriately to consumer market.

• ETRI Journal
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• v.44 no.6
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• pp.955-965
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• 2022

A low Earth orbit (LEO) satellite constellation could be used to provide network coverage for the entire globe. This study considers multi-beam frequency reuse in LEO satellite systems. In such a system, the channel is time-varying due to the fast movement of the satellite. This study proposes an efficient power and bandwidth allocation method that employs two linear machine learning algorithms and take channel conditions and traffic demand (TD) as input. With the aid of a simple linear system, the proposed scheme allows for the optimum allocation of resources under dynamic channel and TD conditions. Additionally, efficient projection schemes are added to the proposed method so that the provided capacity is best approximated to TD when TD exceeds the maximum allowable system capacity. The simulation results show that the proposed method outperforms existing methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.3
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• pp.1035-1048
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• 2023

The IEEE 802.11 WLAN adopts a random backoff algorithm for its collision avoidance mechanism, and it is well known that the contention-based algorithm may suffer from performance degradation especially in congested networks. In this paper, we design an efficient backoff algorithm that utilizes a reinforcement learning method to determine optimal values of backoffs. The mobile nodes share a common contention window (CW) in our scheme, and using a Q-learning algorithm, they can avoid collisions by finding and implicitly reserving their optimal time slot(s). In addition, we introduce Frame Size Control (FSC) algorithm to minimize the possible degradation of aggregate throughput when the number of nodes exceeds the CW size. Our simulation shows that the proposed backoff algorithm with FSC method outperforms the 802.11 protocol regardless of the traffic conditions, and an analytical modeling proves that our mechanism has a unique operating point that is fair and stable.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.150-150
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• 2021

Soil erosion due to climate change is one of the global environmental issues. Especially, Korea is vulnerable to soil erosion as the frequency of extreme rainfall events and rainfall intensity are increasing. Soil erosion causes various problems such as reduced farmlands, deterioration of water quality in rivers, etc. To these severe problems, understanding the process of soil erosion is the first process. Then, it is necessary to quantify and analyze soil ersoion using an erosion model. Soil erosion models are divided into empirical, conceptual, and physics-based models according to the structures and characteristics of models. This study used GSSHA (Gridded Surface Subsurface Hydrologic Analysis), the physics-based erosion model, running on WMS (Watershed Modeling System) to analyze soil erosion vulnerability of the CheonCheon watershed. In addition, we compared the six sediment transport capacity formulas provided in the model and evaluated the equations fir on this study site. Therefore, this result can be as a primary tool for soil conservation management.

• Annual Conference of KIPS
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• 2023.11a
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• pp.66-69
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• 2023

온라인 저지 시스템은 학습자가 제출한 코드를 평가하기 위해 많은 시스템 자원을 사용한다. 학습자의 코드를 평가하는 방법 중 하나인 코드 효율성 측정은 시간복잡도를 기반으로 평가하기 때문에 대량의 인수를 입력 데이터로 사용한다. 본 연구에서 컨테이너 기술인 도커의 컨트롤 그룹을 활용하여 CPU 자원을 제한한다. 이를 통해 기존에 사용한 데이터보다 적은 데이터를 이용하여 코드 효율성을 측정하는 방법을 제안한다. 제안된 방법에 따르면 최단 경로 계산 문제에서 데이터 크기를 60%, 측정 시간을 33.3% 절감할 수 있는 것으로 나타났다.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.455-462
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• 2001

In this paper, we propose a deterministic algorithm to solve the resource discovery problem, that is, some subset of machines to learn the existence of each other in a large distributed network. Harchol et al. proposed a randomized algorithm solving this problem within O($log^2\;n$) rounds with high probability, which requires O($nlog^2\;n$) connection communication complexity and O($n^2log^2\;n$) pointer communication complexity, where n is the number of machines in the network. His solution is based on randomization method and it is difficult to determine convergence time. We propose an efficient algorithm which improve performance and the non-deterministic characteristics. Our algorithm requires O(log n) rounds which shows O(mlog n) connection communication complexity and O($n^2log\;n$) pointer communication complexity, where m is the number of links in the network.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.117-126
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• 2020

Objective evaluation of the resources of industrial heritage regeneration area is an important prerequisite for design and improvement. The purpose of the study is to comprehensively evaluate the value of the industrial heritage regeneration area. This study identifies the method (model), combining the qualitative factor and quantitative factor. (1) Establish an evaluation system (AHP Hierarchy) based on the resources of regeneration area; (2) Choose an evaluation way based on the type of resource; (3) Calculate the value and total value of various resources in the area. The research is a case study of Canal 5 resort. It expounds the using process of the method and gets the rank and total value of each type of resource in this area, the factors influencing the value (mainly concerned with income), etc. The conclusion is that the value of the reclaimed land should be composed of both the use value and the non-use value; the same factor has different influence on different resources; different factors influence one resource to different extents.

• Journal of the Institute of Convergence Signal Processing
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• v.17 no.1
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• pp.46-52
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• 2016

LTE-Advanced system consisting of the number of cells in the cellular environment because it is built to allow efficient use of limited frequency resources of adjacent cell interference avoidance should be considered. Transition services in accordance with the development of the mobile communication technology, wireless multimedia content from voice-centric mobile communications services and causing a lot of mobile data traffic, such as smart phones and tablet terminals spread of a data-driven surge in mobile data traffic base stations in urban areas by increasing became a reality that can not be prevented. In this paper, we propose a new Hybrid resource allocation technique for improving the performance of the cell boundary and analyzed the performance of the proposed new techniques to perform the simulation using LTE-Advanced system level simulator based on 19cell of cellular system model.