• Journal of Korea Multimedia Society
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• v.6 no.3
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• pp.384-396
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• 2003

Hybrid query processing method is used for preventing server overload that is created by heavy user connection in Web GIS. In Hybrid query processing method, both server and client participate in spatial query processing. But, Hybrid query processing method is restricted in scalability of server and it can't be fundamentally solution for server overload. So, it is necessary for Web GIS to be brought in web clustering technique. In this thesis, we propose load-balancing method that uses proximity of query region. In this paper, we create tile groups that have relation each tile in same group is very close, and forward client request to the server that can have maximum rate of buffer reuse with considering characteristic of spatial query. With out load balancing method, buffet in server is optimized for exploring spatial index tree and increase rate of buffer reuse, so it can be reduced amount of disk access and increase system performance.

• Journal of Advanced Navigation Technology
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• v.3 no.2
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• pp.185-195
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• 1999

항공이동통신분야에서는 아날로그형 음성통신의 한계점을 극복하고, 운용자의 업무 부담을 경감할 목적으로 항공이동데이터통신망(VDL)을 이용한 데이터 통신이 항공운용통신(AOC) 분야에서 발전되었으며, 이를 항공교통서비스(ATS) 분야에 적용하기 위한 연구가 국제민간항공기구(ICAO)의 CNS/ATM 구축 권고에 의하여 미국, 유럽 등 항공 선진국에서 진행되고 있다. 본 논문은 항공교통서비스 분야에 VDL을 이용한 데이터 링크 서비스를 제공하기 위하여 디지털형의 출발전비행허가(PDC) 시스템을 개발한 내용의 결과이다. 개발된 PDC 시스템은 하나의 PC급 단일 시스템으로 항공교통관제소, VDL 통신망, 관제사 등이 원격으로 연동되어 실시간 및 동시에 PDC 정보를 처리하여야 한다. 이를 위하여 제안된 기법은 하나의 프로세서에 여러 개의 쓰레드를 갖는 멀티 쓰레드 방식이 도입되어 설계되었다. 멀티 쓰레드 방식이 사용된 이유는 시스템의 간소화, 효율적인 내부 자원의 이용, 데이터 처리에 있어서 우수한 성능을 발휘하기 때문이다. 본 논문은 김포공항 PDC 시스템의 구조 및 설계 내용을 기술하고, 실제 운용 결과에 대한 데이터를 분석하였다. 김포공항 PDC 시스템의 운용결과를 이용한 분석한 결과, 운용초기단계로 모든 항공기에 시스템이 구축되지 않아 매일 평균 25대의 항공기가 운용하여 평균 10%의 이용률을 나타내며, 최대 34대의 항공기가 이용하고 있다. 메시지 송/수신에 걸리는 시간을 분석한 결과, 항공기의 PDC 요청부터 MAS의 수신에 소요되는 시간은 최소 14초부터 최대 983초(16분 23초)까지로써, 평균 122초(2분 2초)의 시간을 나타내었다. 또한 신뢰성을 확인하기 위하여 가용도를 계산한 결과 99.7%로써 상당히 신뢰할 수 있는 수준이었다. 또한, 다중 처리를 위하여 사용된 방식인 멀티 쓰레드 방식이 적절히 동작함을 확인할 수 있었다. 앞으로, 전체 연동 시스템이 자동화로 구축될 경우, PDC의 요청부터 발송 및 확인까지 상당히 짧은 시간 내에 이루어져 관제업무 능률을 향상시킬 수 있을 것이다.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.44-51
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• 2006

In this paper, we present a network-based integrated nesting system, that is adapted a current engineering concept. Generally, sheet cutting processes proceed in turn following an existing order In this study, however, the special characteristics of these processes were analyzed and the processes were redesigned with distributed design so that they could be operated in a client/server environment. Also, the necessary sheet material cutting processes, part CAD, nesting, part CAM, and NC post-processor capabilities, were implemented so that many workers could handle them all on the Web. Compared to existing commonly used systems, the developed system can provide integrated work environment for cutting automation, allow job collaboration between workers, and it has proved that it can shorten the standby time for work. By grafting computer system technologies to sheet material cutting automation field, this research expects to contribute to the enhancement of factory automation efficiency and productivity.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.13-20
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• 2007

Decision tree is one of the most useful analysis methods for various data mining functions, including prediction, classification, etc, from massive data. Decision tree grows by splitting nodes, during which the purity increases. It is needed to stop splitting nodes when the purity does not increase effectively or new leaves does not contain meaningful number of records. Pruning is done if a branch does not show certain level of performance. By pruning, the structure of decision tree is changed and it is implied that the previous splitting of the parent node was not effective. It is also implied that the splitting of the ancestor nodes were not effective and the choices of attributes and criteria in splitting them were not successful. It should be noticed that new attributes or criteria might be selected to split such nodes for better tries. In this paper, we suggest a procedure to modify decision tree by Fuzzy theory and splitting as an integrated approach.

• Journal of Intelligence and Information Systems
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• v.3 no.1
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• pp.143-160
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• 1997

현재 우리 군에서는 첨단과학무기를 이용한 전투력을 신속히 집중, 전환시키고 효과적으로 통합 운용해야하는 각급 제대의 지휘관 및 참모의 지휘통제능력 향상을 위하여 첨단 컴퓨터장비를 이용하여 시뮬레이션 기법을 통한 워게임 모델을 개발하여 이를 이용한 훈련을 실시하고 있다. 이 워게임 모델중 지상전투의 가장 기본이 되는 근접전투 시뮬레이션은 미국에서 개발도입된 "COBRA" 시스템을 이용하고 있으나 한국실정에 맞는 시스템으로 확장 및 유지보수가 어렵고, 상위시스템의 서브시스템으로만 운영되고있어 자체 교육훈련 및 전투분석을 위한 단독시스템으로 운영이 어려운 실정이다. 본 논문에서는 이러한 문제점을 극복하고, 방대한 양의 지식을 효율적이고 효과적으로 표현할 수 있으며 시스템의 확장 및 유지보수가 용이하고 우리실정에 적합한 전투 훈련을 실시하도록 지원하는 워게임(근접전투) 지원용 멀티미디어 전문가시스템을 개발하였다. 본 논문에서 개발한 전문가시스템은 쌍방이 부대들의 근접전투를 실시할 때 실전에서 나타날 수 있는 가능한 모든 상황의 데이터를 이용하여 전투상황을 분석하며, 기존의 획일적이고 단순한 형태로 결과를 판정하던 것을 전투원의 사기, 체력, 전투한계 등 심리적 요소까지 고려함으로써 새로이 변화되는 전쟁양상에 쉽게 적응할 수 있는 확장성 및 유지보수가 용이하며 시스템 단독으로 운영하여 반복적으로 전투를 분석하고 교육훈련을 실시하도록 함으로써 실전적이고 실질적인 근접전투 워게임지원이 가능하다. 본 논문에서는 전문가 시스템을 개발함에 있어서 지식베이스 모듈, 추론엔진 모듈 및 설명 모듈은 전문가 시스템 개발도구인 Smart Elements를 이용하여 구축하였으며, 사용자 인터페이스 모듈은 멀티미디어 저적도구인 툴북 3.0을 이용하였으며, 마지막으로 전체적인 모듈은 API를 이용 통합하여 하나의 응용소프트웨어를 생성하였다.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.175-182
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• 2018

The purpose of this study was to examine the influence of factors related to whether or not to take oral examinations for 104,811 economically active population aged 25 to 54 years using the 2016 community health survey data. Multiple logistic regression analysis was performed to oral examination rate the effect general characteristics, socioeconomic and geographical characteristics, and oral health management behavior. The higher who age, the higher who education, have experience scaling, and the better who subjective oral health status, unmet dental needs rate of oral examination was higher. The higher the income level, the lower the oral examination rate. Age of economically active population, marital status, education level, area, income quartile, empolyment, scaling experience, unmet dental needs, there was a significant effect whether oral examination. The purpose of this study is to establish an positive basis for an effective oral examination program to improve accessibility to oral examinations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.493-502
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• 2003

In this paper, to solve some problems of the Mobile IP and local registration strategy we propose a method that can effectively support real-time traffics sensitive to delay time and packet loss. The proposed method reduces the registration time after a Mobile Node's movement between networks by carrying out the pre-registration for the domain which it will move into the network information of the link layer of cdma2000 system, at the boundary cell's handoff zone. Through the cost analysis and simulation it is shown that the proposed scheme yield a better performance compared with the Mobile IP and local registration strategies in terms of packet loss for parameters; variation of the velocity of a Mobile Node, and a distance between the Mobile Node and home networks, etc.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.816-823
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• 2010

Recently research efforts for ubiquitous technology that includes RFID(Radio Frequency Deification and sensor networks are conducted very actively The architectural framework of the USN sensor network discovery service. The survey of the USN technology is conducted on four technological visions that contain USN system technology USN networking technology and USN middleware along with the service platform, With respect to each technological division domestic and worldwide leading research projects are primarily explored with their technical features and research projects are primarily explored with their technical features and research outputs. Boasted on the result of the survey we establish a USN software model that includes data sensing, sensor data storage sensor data storage sensor data naming and sensor feed name service. This main objective of this model is to provide a reference model for the facilitation of USN application developments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.9
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• pp.548-556
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• 2014

To cope with recently increasing demand for data traffics, heterogeneous networks have been actively studied, where small cells are deployed within a macro cell coverage with the same frequency band. To mitigate the interference from the macro cell to small cells, an enhanced Inter-cell Interference Coordination (eICIC) technique has been proposed, where ABS (Almost Blank Subframe) is used in time domain. However, there is a waste of resource since no data is transmitted in a macro-cell in ABS. In this paper, we propose a new interference management method by using a 3D sector beam based on Active Antenna System (AAS), where Genetic Algorithm (GA) is applied to reduce the antenna gain toward a small-cell. With the proposed scheme, the macro-cell and small cells can transmit data at the same time with the AAS antenna pattern generating reduced interference to small cells. The performance of the proposed scheme is evaluated by using an LTE-Advanced system level simulator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.363-367
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• 2016

A test section of a supersonic wind tunnel was designed for the analysis of flow characteristics over a backward-facing step with Mach 1.0 slot injection in a supersonic flow of Mach 2.5. The cavity flow of a high-speed vehicle is very complex at supersonic speed, so it is necessary to do experiments using supersonic wind tunnels to verify numerical analysis methods. The previous 2D symmetrical nozzle was replaced with an asymmetrical nozzle. The inviscid nozzle contour was designed using Method of Characteristics (MOC), and the boundary layer thickness correction was reflected by experimental data from the wind tunnel. The results were compared with a CFD analysis. The PID control system was changed to be based on the change of tank pressure. This improved the control efficiency, and the run times of supersonic flow increased by about 1 second. The flow characteristics over a backward facing step with slot injection were visualized by a Schlieren device. This equipment will be used for an experimental study of the film cooling effectiveness over a cavity with various velocities, mass flows, and temperatures.