• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1414-1419
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• 2011

In this paper we study the modeling to quantitatively assess the failure rate of USN system designed for fault-tolerant architecture, aiming at applying the world's best domestic USN technology to safety-critical railways. In order to apply the USN system to the safety-critical field like a train control sector that the failures of controllers may cause severe railway accidents such as train collision and derailment, the quantitative reliability and safety evaluation recommended in IEC 62278 must be preceded. We also develop the evaluation model for overall system failure rate for the distributed network structure, which is the characteristics of USN system. Especially, we allocate reliability targets to component units, and present an availability evaluation plan through the plan on the quantitative achievement of failure rate for sensor nodes, gateways, radio-communication network and servers, along with the failure rate model of the overall system considering network operational features.

• Journal of Information Processing Systems
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• 제14권2호
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• pp.377-395
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• 2018

Aiming at the problem of service reliability in resource reservation in cloud computing environments, a model of dynamic cloud resource reservation based on trust is proposed. A domain-specific cloud management architecture is designed in which resources are divided into different management domains according to the types of service for easier management. A dynamic resource reservation mechanism (DRRM) is used to test users' reservation requests and reserve resources for users. According to user preference, several resources are chosen to be candidate resources by fuzzy cluster analysis. The fuzzy evaluation method and a two-way trust evaluation mechanism are adopted to improve the availability and credibility of the model. An analysis and simulation experiments show that this model can increase the flexibility of resource reservation and improve user satisfaction.

• 전기학회논문지
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• 제56권10호
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• pp.1852-1858
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• 2007

To Increase availability and to enhance the safety, the modernization of Instrumentation & Control (I&C) systems is considered. The extended use of the digital technology lets nuclear power plants(NPPs) to replace their old analog systems with some proven digital systems. To adapt digital equipment to plants effectively and systematically, however, there must be an essential prerequisite, which is to evaluate current I&C equipment. This paper shows a practical methodology to evaluate the current status and reliability of I&C systems of NPPs using Reliability Evaluation System(RES) before performing upgrades or replacements for systems. The proposed method was applied to KORI Unit 2. The proposed method shows the current status of operating I&C systems effectively for upgrading I&C systems.

• 한국안전학회지
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• 제24권3호
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• pp.88-95
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• 2009

Most of subway stations are located underground and the number of passengers is far more than that of designed value, therefore the risk of accident is growing bigger and serious damage is expected in case of disaster. In Korea the period of evacuation study is short and numerical and experimental data of evacuation phenomena in subway station is rare. Many egress evaluation depend on foreign commercial S/Ws which are not yet proven its availability in special case such as subway station. In this paper outflow coefficients which are essential in egress evaluation are calculated at train door, stairway and turnstile at 3 most crowed subway stations. This numerical data can be used in prediction of egress evaluation and the result of other prediction methods can be verified with these experimental data.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.431-436
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• 2001

Rockfall has long been a serious problem, especially derailment of train running on the track in mountainous regions. The purpose of this study is to suggest the reasonable items of check and evaluation to railroad rock slopes for safe maintenance and management of rockfall-worried railroad sites. Therefore, main and sub items were extracted from the survey of foreign and other authorities' cases and evaluation table (temporary) composed of items classified by important degree was suggested. To evaluate the availability and reasonability of items, statistical analysis based on field investigation namely SMR(Slope Mass Rating) and explanation values was carried.

• 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.

• Educational Technology International
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• 제12권2호
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• pp.117-134
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• 2011

Online education is moving forward with more interactive environments due to the availability of new technologies. In addition, many researches have represented that interaction and high motivation are very critical factors in order to improve students' motivation and teaching effectiveness in online learning and education. Therefore, it is very meaningful for students and educators that motivation and effectiveness are observed by positive expectation and interaction satisfaction in their online counseling courses. For this study, two important instruments are used: Modified Short Forms of Instructional Materials Motivation Survey and Student Evaluation of Online Teaching Effectiveness. Results show that high expected students who are satisfied with interaction indicate higher motivation and evaluation on the online teaching effectiveness than low expected students who are not satisfied with interaction.

• 제어로봇시스템학회논문지
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• 제20권2호
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• pp.112-119
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• 2014

A force support system is composed of capital components such as combat equipments, supplies and so on to enable constant fighting power capability. Private technology level evaluation is on the rise as an important spin-on method in force support systems, which requires 92% of total munitions requirements, to obtain superior private technology. The evaluation of the private sector technology level on Korean force support systems has been conducted for the first time as follows: this research chose 38 items to be acquired within 2-3 years and grouped either identical or similar technology among those 38 items. A technology evaluating method was established based on the analysis of domestic and foreign technology level evaluations. Evaluation was performed by a Delphi survey from 180 private and military experts. To obtain an objective index and raise political availability, a technology system map and standard document were developed and applied to all 38 items.

• Journal of Preventive Medicine and Public Health
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• 제41권2호
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• pp.69-73
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• 2008

To curb a rapid increase in expenditures for pharmaceuticals, the Korean government introduced a positive list system and a negotiation process for drug prices at the end of 2006. Economic evaluation of pharmaceuticals has begun to have a pivotal role in the listing and pricing of drugs for the Korean National Health Insurance. There are some points to discuss regarding the use of economic evaluation in the listing and pricing in the context of the Korean system. First, the listing and pricing processes have been fragmented, evoking complaints from pharmaceutical companies and delaying the access of new drugs to patients. Second, there is a concern that the positive list system may limit the range and availability of drugs for patients to choose for treatment. Third, the time schedule for de-listing of existing drugs may not be realistic. Fourth, it is not always easy to provide reliable evidence of cost-effectiveness due to a lack of materials. Fifth, there is no consensus on the range of the ICER (incremental cost-effectiveness ratio) acceptable to the Korean society. In conclusion, in the near future, it will be necessary to evaluate the achievements that the economic evaluation has provided to the Korean society.

• 교육시설 논문지
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• 제23권1호
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• pp.23-32
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• 2016

This research aims to securement of crime prevention for school violence and invasion from outside etc. For crime prevention efficiency secure, It has purpose for school current state comprehension and prevention essential elements deduction autonomously etc. Furthermore, school facility crime dangerousness evaluation checklist is looked for autonomous monitoring tools. This checklist made from analysis of frequency, importance and check availability of 6 native and foreign existing CPTED evaluation's 360 indexes. Then, 81 indexes was derived from analysis, and that indexs verified through focus group interview. Finally, total 47 articles checklist emerged with general details, external school, internal school, and school administrative managements. Through this checklist, school can select essential elements of the preferential crime prevention autonomously, and so it is expected to prompt improvement of crime dangerousness elements, school violence and reduction of crime rate.