• The Magazine of the IEIE
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• v.19 no.4
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• pp.1-7
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• 1992

IBM이 16비트 PC를 처음 선보인 81년 이후 오늘에 이르기까지 10여년간의 운영체제(0S) 시장은 마이크로소프트(MS)사의 독주시대로 요약할 수 있다. 그러나 지금까지 이렇다 할 변화를 보이지 않던 OS제품은 90년대에 들어서면서 커다란 변화의 조짐에 횝싸이고 있다. 그동안 8086, 80286등의 마이크로프로세서를 탑재한 16비트 PC시장이 80386,80486등을 탑재한 32비트 시장으로 급변하기 시작했고 종전 데스크탑 일변도의 PC시장은 랩톱,노트북형 등의 휴대형컴퓨터와 펜컴퓨터,멀티미디어 등의 차세대 제품등으로 세분화되기 시작한 것이다. 또 32비트 시대가 다가오면서 한사람이 한 대의 PC로 일을 하는 종전 PC운용환경은 넷워킹과 멀티테스킹이 강조되는 다중작업 환경으로 전환되고 있으며 윈도즈(Windows) 3.0의 대히트로 IBM PC에서도 GUI(그래픽 사용자인터페이스) 환경을 요구, 이를 위한 새로운 05의 등장이 불가피해지고 있다. 게다가 지금까지 메인프레임을 중심으로 한 중앙집중방식의 컴퓨터환경이 다운사이징화 되면서 넷워크 환경을 기반으로 한 PC의 역할이 크게 강조, 이를 위한 운영체제 또한 새로운 영역으로 대두되고 있다. 불과 1∼2년 사이에 급진전되고 있는 이같은 변화의 물결은 필연적으로 다양한 운영체제의 개발을 가져왔고 이를 통해 차세대 PC시장을 주도하기 위한 업계의 패권다툼은 전쟁을 방불케할 만큼 치열해지고 있다. MS사의 전유물이었던 DOS 영역에서는 최근 노벨사와의 합병으로 전열을 가 다듬은 디지틀리서치사가 가세, 한판승부를 선언하고 나섰으며 고성능 PC시대의 패권을 잡기 위해 10년지기였던 IBM과 MS사는 각각 OS/2와 윈도즈를 내세우고 양보할 수 없는 힘겨루기에 들어갔다. 또 이들 양사는 펜컴퓨터,멀티미디어등 차세대제품의 운영체제 시장을 둘러싸고 일찍부터 격전에 들어갔으며 IBM과 MS사의 혼전을 틈타 썬마이크로시스템을 필두로한 워크스테이션 업체 및 유닉스진영까지 고성능 PC시장을 겨냥한 OS를 속속 개발, 90년대의 OS 전쟁은 한치 앞을 내다볼 수 없는 안개국면으로 접어들고 있다. DOS에서 32비트시대,펜컴퓨터, 멀티미디어에 이르는 차세대제품을 둘러싼 업계의 OS 쟁탈전을 통해 OS의 발전동향과 미래를 전망해 본다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.792-803
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• 2005

Ultra wide band (UWB) technology will be applied in the high rare wireless personal area networks (WPANs) for its high rate, low power, and innate immunity to multipath fading. In this paper, a power aware multi-hop packet relay MAC protocol in UWB based WPANs is proposed and a power aware path status factor (PAPSF), which is derived from SINR and power resource condition of each device, is used to select a suitable relay node. Compared with relaying by piconet coordinator (PNC), which is easily chosen by other ad hoc routing protocol, the new scheme can achieve hi임or throughput, decrease the time required for transmitting high power signal and we can easily distribute the battery power consumption from PNC to other devices in the piconet to prevent the PNC device using up its battery too fast and finally avoid PNC handover too frequently.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.205-218
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• 2012

Mobility management of the mobile nodes and provision of seamless handover is crucial to an efficient support for the global roaming of the mobile nodes in next-generation wireless networks. Mobile IPv6 and mobility management in extended IP layer, which highly depend on traffic characteristics and user mobility models, were proposed by the IETF. Therefore, to evaluate the in-depth performance about these factors is important. Generally, the performance of IPv6-based mobility management protocol is evaluated through simulation. This paper shows the correlation between network parameters and performance metrics through numerical results, which is investigated how influence handoff latency and packet loss. And this paper uses mathematical analysis of the system parameters, such as the subnet residence time, the packet arrival rate and delay in wireless connection through the analytical framework which evaluate the performance of IPv6-based mobility management protocol.

• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.385-398
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• 2016

This research analyzed domestic newspapers' agenda setting trend and meaning construction process on the issue of marine environment by year. The research conducted a language network analysis and used R program and Netminer program to analyze four major daily newspapers' news coverages (Dong-A, Joongang, Hanhyoreh, and Kyunghyang) for the last ten years (2005-2014). The results show that the issue of marine environment in Korean media reports are signified in the economic context. For the last ten years, news reports are mainly focused on the 'development' issue of marine environment, without distinction of year. The core key words of the networks are "development", "plan", and "project." However, diverse strategies for 'preservation' are not covered in media reports as a major issue. The importance of effective preservation and reasonable development should be considered in a balanced way. Korean media coverages mainly concentrate on the development issue, and it has a strong influence on considering the marine environment area as an object of development. Future direction and implication of the press reports related to marine environment are discussed.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.21-30
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• 2007

Simulation means modeling structures or behaviors of the various objects, and experimenting them on the computer system. And the major approaches are DEVS(Discrete Event Systems Specification). Petri-net or Automata and so on. But, the simulation problems are getting more complex or complicated these days, so that an intelligent agent-based is being studied. In this paper, we are describing an intelligent agent-based simulation tool, which can supports the simulation experiment more efficiently. The significances of our system can be described as follows. First, the system can provide some AI algorithms through the system libraries. Second, the system supports simple method of designing the simulation model, since it's been built under the Finite State Machine (FSM) structure. And finally, the system acts as a simulation framework by supporting user not only the simulation engine, but also user-friendly tools, such as modeler scriptor and simulator. The system mainly consists of main simulation engine, utility tools, and some other assist tools, and it is tested and showed some efficient results in the three different problems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.6
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• pp.77-87
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• 2007

It will need a quite long time to replace IPv4 protocol, which currently used, with IPv6 protocol completely, thus we will use both IPv4 and IPv6 together in the Internet during the period. For coexisting protocols, IETF standardized various IPv4/IPv6 transition mechanisms. However, new security problems of IPsec adaptation and IPv6 packet filtering can be raised by tunneling mechanism which mainly used in transition mechanisms. To resolve these problems, we suggested two improved schemes for packet filtering functions, which consists of an inner header filtering scheme and a dedicated filtering scheme for IPv4/IPv6 transition mechanisms. Also we implemented our proposed schemes based on Linux Netfilter framework, and we tested their filtering functions and evaluated experimental performance of our implementation on IPv4/IPv6 transition testbed. These evaluation tests indicated that our improved packet filtering functions can solve packet filtering problems of IPv4/IPv6 transition mechanisms without severely affecting system performance.

• Journal of Internet Computing and Services
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• v.20 no.1
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• pp.87-96
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• 2019

In this paper, we propose a MapReduce-supported clustering technique for collecting and classifying distributed workflow enactment event logs as a preprocessing tool. Especially, we would call the distributed workflow enactment event logs as Workflow BIG-Logs, because they are satisfied with as well as well-fitted to the 5V properties of BIG-Data like Volume, Velocity, Variety, Veracity and Value. The clustering technique we develop in this paper is intentionally devised for the preprocessing phase of a specific workflow process mining and analysis algorithm based upon the workflow BIG-Logs. In other words, It uses the Map-Reduce framework as a Workflow BIG-Logs processing platform, it supports the IEEE XES standard data format, and it is eventually dedicated for the preprocessing phase of the ${\rho}$-Algorithm that is a typical workflow process mining algorithm based on the structured information control nets. More precisely, The Workflow BIG-Logs can be classified into two types: of activity-based clustering patterns and performer-based clustering patterns, and we try to implement an activity-based clustering pattern algorithm based upon the Map-Reduce framework. Finally, we try to verify the proposed clustering technique by carrying out an experimental study on the workflow enactment event log dataset released by the BPI Challenges.

• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.117-128
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• 2002

Virtual LAN (VLAN) is an architecture to enable communication between end stations as if they were on the same LAN regardless of their physical locations. VLAN defines a limited broadcast domain to reduce the bandwidth waste. The Newbridge Inc. developed a layer 3 VLAN product called VIVID, which configures a VLAN based on W subnet addresses. In a VIVID system, a single route server is deployed for address resolution, VLAN configuration, and data broadcasting to a VLAN. If the size of the network, over which the VLANS supported by the VIVID system spans, becomes larger, this single route server could become a bottleneck point of the system performance. One possible approach to cope with this problem is to deploy multiple route servers. We propose two architectures, organic and independent, to expand the original VIVID system to deploy multiple route servers. A course of simulations are done to analyze the performance of each architecture that we propose. The simulation results show that the performances of the proposed architectures depend on the lengths of VLAN broadcasting sessions and the number of broadcast data frames generated by a session. It has also been shown that there are tradeoffs between the scalability of the architecture and their efficiency in data transmissions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.161-168
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• 2019

Recently, video equipments such as CCTV, which is spreading rapidly, is being used as a means to monitor and cope with abnormal situations in almost governments, companies, and households. However, in most cases, since recognizing the abnormal situation is carried out by the monitoring person, the immediate response is difficult and is used only for post-analysis. In this paper, we present the results of the development of video surveillance system that automatically recognizing the abnormal situations and sending such events to the smartphone immediately using the latest deep learning technology. The proposed system extracts skeletons from the human objects in real time using Openpose library and then recognizes the human behaviors automatically using deep learning technology. To this end, we reconstruct Openpose library, which developed in the Caffe framework, on Darknet framework to improve real-time processing. We also verified the performance improvement through experiments. The system to be introduced in this paper has accurate and fast behavioral recognition performance and scalability, so it is expected that it can be used for video surveillance systems for various applications.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.6
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• pp.157-165
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• 2020

Aiming at the development of neural network and self-driving data set, it is also an idea to improve the performance of network model to detect moving objects by dividing the data set. In Darknet network framework, the YOLOv4 (You Only Look Once v4) network model was used to train and test Udacity data set. According to 7 proportions of the Udacity data set, it was divided into three subsets including training set, validation set and test set. K-means++ algorithm was used to conduct dimensional clustering of object boxes in 7 groups. By adjusting the super parameters of YOLOv4 network for training, Optimal model parameters for 7 groups were obtained respectively. These model parameters were used to detect and compare 7 test sets respectively. The experimental results showed that YOLOv4 can effectively detect the large, medium and small moving objects represented by Truck, Car and Pedestrian in the Udacity data set. When the ratio of training set, validation set and test set is 7:1.5:1.5, the optimal model parameters of the YOLOv4 have highest detection performance. The values show mAP50 reaching 80.89%, mAP75 reaching 47.08%, and the detection speed reaching 10.56 FPS.