• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.898-903
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• 2002

The railroad is a means of large transportation which has many talents such as a safety and a regularity. That is a results from various confidential performance tests and evaluations of the system. The railroad system consist of various subsystems - vehicle, power supply, signal, communications, track structures, operations, etc. Among them, as an item of safety evaluation there is a measurement of wheel/rail force, so called a measurement of derailment coefficient. This is a very important item because a derailment of a train will bring about a big accident. Especially it is more inportant in high speed rail of which operation speed is over two times as fast as existing rail. In this paper, it is introduced to preprocess the wheelset for measuring wheel/rail force of high speed rail, such as to treat a measuring wheelset, its finite element analysis, adhesion of strain gauges and static load test.

• 전자통신동향분석
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• 제17권3호통권75호
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• pp.80-86
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• 2002

본 연구는 현재 통신서비스 산업에서 가장 많이 사용하고 있는 5개 예측모형(단순 성장 모형, 단순 Logistic 모형, Gompertz 모형, 확장 Bass 모형, 시간 변동 Bass 모형)을 이용한 초고속 인터넷 가입자에 대한 예측력을 비교 평가하는 데 있다. 예측모형의 추정 방법으로 비선형 회귀방정식(nonlinear regression)을 사용하여 추정의 효율성을 높였다. 예측력 비교분석 기준은 (i) 포화점에 대한 타당성 (ii) 모수에 대한 통계적 유의성 (iii) 실제치 대비 예측치에 대한 AAD 기준을 통하여 예측모형의 예측력을 비교 평가하였다. 본 연구에서 실시한 방법론에 따라 다섯 가지 통신서비스 예측모형의 예측력을 분석한 결과 가장 작은 AAD를 나타낸 예측모형은 Log-Logistic 모형으로 나타났으며, 가장 큰 AAD를 나타낸 예측모형은 단순 Logistic 모형으로 나타났다. 또한 AAD 기준에서 보면 일반적으로 많이 사용하고 있는 Gompertz 예측모형과 Bass 모형 중에서는 Gompertz 예측모형이 더 우월한 것으로 나타났다.

• 한국정보통신학회논문지
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• 제15권3호
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• pp.725-732
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• 2011

RFID/USN을 적용한 항만 컨테이너 터미널의 효과적인 운영에 관한 방안이 모색되고 있다. 본 논문에서는 각 컨테이너에 무선 센서 노드가 하나씩 배치되어 있다는 가정하에 각 노드가 인접노드로부터 오는 전파의 세기 (RSSI: Received Signal Strength Indicator)값을 측정하여 서버로 전송하면 이를 근거로 항만 컨테이너 야적장(장치장)내에 적재된 컨테이너의 위치를 실시간으로 확인하는 방안을 제안한다. 이를 위하여 RSSI값에 근거한 컨테이너 위치 결정 알고리즘을 제안하고 성능을 분석한 후 응용 프로그램으로 구현하여 컨테이너별 위치확인이 가능함을 확인하였다.

• 전기학회논문지P
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• 제66권2호
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• pp.58-62
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• 2017

This paper presents a novel prototype of the resonant AC link snubber circuit for the three-phase sinwave soft-switching PWM inverter. In principle, its operating principle is described, and the performance evaluations of the specific instantaneous space voltage modulated three-phase sinewave soft switching PWM inverter incorporating a resonant AC link snubber is illustrated, and evaluated, introducing the specific space voltage vector modulation implementation. It is conferred that the validity of three-phase soft-switching inverter treated here in setup experiment.

• 대한인간공학회지
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• 제12권1호
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• pp.17-24
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• 1993

Today, rapid development and timeliness of introducing a new product be- comes a more influencing factor of determing its competitive power due to a shortened product cycle, while rapid improvement of manufacturing technology makes product design and manufacturing fuse together. This implies that prod- uct usability evaluation and improvement starts right from its design phase, resulting in less development time and cost. To make this possible, proper as- sessment of human reach is one of essential functions for ergonomic product us- ability evaluation, specifically in the platform of computer-aided ergonomic evaluation models or any CAD system with a built-in man model. In this study, an analytic reach prediction algorithm ensuring the posture that human naturally takes, is presented by employing the methods developed for robot kinematics. Among robot kinematic methods for solving the multi-link system, the resolved motion method was found to be effective to solve human reach as a redundant manipulator model. Also, the joint range availability was used as a performance fonction to guarantee human naturalness. The result is expected to be directly applicable to product usability evaluations.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.316-321
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• 2003

The railroad is a means of large transportation which has many talents such as a safety and a regularity. That is a results from various confidential performance tests and evaluations of the system. The railroad system consist of various subsystems - vehicle, power supply, signal, communications, track structures, operations, etc. Among them, as an item of safety evaluation there is a measurement of wheel/rail force, so called a measurement of derailment coefficient. This is a very important item because a derailment of a train will bring about a big accident. Especially it is more important in high speed rail of which operation speed is over two times as fast as existing rail. In this paper, it is introduced to preprocess the wheelset for measuring wheel/rail force of high speed rail, such as to treat a measuring wheelset, adhesion of strain gauges and static load test, running test result of main line.

• 한국태양에너지학회 논문집
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• 제33권6호
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• pp.32-38
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• 2013

In an efforts to encourage renewable energy deployment, the government has initiated so called 1 million green homes program but the accumulated installation capacity of small wind turbine has been about 70kW. It can be explained in several ways such that current subsidy program does not meet public expectations, economic feasibility of wind energy is in doubt or acoustic emission is significant etc. The author investigated annual energy production of Skystream 3.7 wind turbine using measured power curve and wind resource data. The measured power curve of the small wind turbine was obtained through power performance tests at Wol-Ryoung test site. AEP(Annual Energy Production) and CF(Capacity Factor) were evaluated at selected locations with the measured power curve.

• Nuclear Engineering and Technology
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• 제48권1호
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• pp.26-32
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• 2016

Research and development (R&D) methodology for the practical use of accident tolerant fuel (ATF) in commercial light water reactors is discussed in the present review. The identification and quantification of the R&D-metrics and the attribute of candidate ATF-concepts, recognition of the gap between the present R&D status and the targeted practical use, prioritization of the R&D, and technology screening schemes are important for achieving a common understanding on technology screening process among stakeholders in the near term and in developing an efficient R&D track toward practical use. Technology readiness levels and attribute guides are considered to be proper indices for these evaluations. In the midterm, the selected ATF-concepts will be developed toward the technology readiness level-5, at which stage the performance of the prototype fuel rods and the practicality of industrial scale fuel manufacturing will be verified and validated. Regarding the screened-out concepts, which are recognized to have attractive potentials, the fundamental R&D should be continued in the midterm to find ways of addressing showstoppers.

• 산업경영시스템학회지
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• 제29권2호
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• pp.1-6
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• 2006

This study proposes a new approach which combines Data Envelopment Analysis(DEA) and the Analytic Hierarchy Process(AHP) techniques to effectively evaluate Decision Making Units(DMUs). While DEA evaluates a quantitative data set, employs linear programming to obtain input and output weights and ranks the performance of DMUs, AHP evaluates the qualitative data retrieved from expert opinions and other managerial information in specifying weights. The objective of this research is to design a decision support process for managers to incorporate positive aspects of DEA's absolute numerical evaluations and AHP's human preference structure values. It is believed that a pragmatic manager will be more receptive to the results that include subjective opinions incorporated into the evaluation of the efficiency of each DMU efficiency. The WPDEA method provides better discrimination than the DEA method by reducing the number of efficient units.

• Smart Structures and Systems
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• 제14권2호
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• pp.129-144
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• 2014

In this paper, a fuzzy inference system and an analytical hierarchy process-based online evaluation technique is developed to monitor the condition of the 32-km Donghai Bridge in Shanghai. The system has 478 sensors distributed along eight segments selected from the whole bridge. An online evaluation subsystem is realized, which uses raw data and extracted features or indices to give a set of hierarchically organized condition evaluations. The thresholds of each index were set to an initial value obtained from a structure damage and performance evolution analysis of the bridge. After one year of baseline monitoring, the initial threshold system was updated from the collected data. The results show that the techniques described are valid and reliable. The online method fulfills long-term infrastructure health monitoring requirements for the Donghai Bridge.