• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.413-428
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• 2013

Purpose: The purpose of this study was to evaluate students and optometrist opinion of the usefulness of different subjects of optometry curriculum.This date will then be used as base-line data during a process of curriculum development Methods: 292 of ophthalmic optic's students and 123 of optometrists were surveyed in the usefulness of curriculum (five-point scale) followed by statistical analysis of the results. Results: Optometrists gave a higher average score for curriculum usefulness (3.89) than the students (3.71). The subject which showed the highest usefulness for the student was optometry (4.55) but clinical practice was the highest for the optometrist (4.48). There was significant differences (p<.05) on optics, ophthalmology, basic science, optometrist related subject and foreign language but optometry and contact lenses showed high usefulness in common without significant difference. The usefulness of subject for the student showed significant difference according to gender, grade, age, and desired working place and has demonstrated significant difference depend on gender, age, scholarship, total working experience as an optometrist, workplace, and position for optometrists as well. Conclusions: It is necessary to continue research for the development of standard and bench-marked curriculum for ophthalmic optics and also the curriculum, which reflecting the usefulness and needs obtained from ophthalmic optics' students and optometrists need to be developed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.37-43
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• 2015

Evaporative cooling is a very effective way for exhaust heat recovery that uses both latent heat and sensible heat. This study investigated the performance of a heat recovery system using evaporative cooling. The experimental apparatus comprised a plastic heat exchanger, a water spray nozzle, an air blowing fan, a water circulation pump, and measuring sensors for the temperature, humidity, and flow rate. The effectiveness of the sensible heat recovery without evaporation was measured and compared with that of the total heat recovery with evaporation. The effectiveness of the sensible and total heat recoveries decreased as the air flow rate increased, and a much higher effectiveness was obtained with the counterflow arrangement in both cases. For total heat recovery, the effectiveness increased with the water flow rate, and the parallel flow arrangement was found to be more sensitive to the water flow rate than the counterflow arrangement.

• Transactions of the Korean hydrogen and new energy society
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• v.10 no.1
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• pp.19-26
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• 1999

The effectiveness of a double-tube heat exchanger has been investigated experimentally. This problem is of particular interest in the design of the heat exchanger in a hydrogen liquefaction system. Temperature, pressure, and mass flow rate for hydrogen were measured both in inner tube and in annulus of a double-tube heat exchanger. The effectiveness could be evaluated from the measured temperature and mass flow rate. It is found that the effectiveness increases with an increase in the heat transfer area of a double-tube heat exchanger and with a decrease of the heat capacity ratio. But the increase rate of the effectiveness decreased with a decrease of the heat capacity ratio. Therefore, it is presented that a criterion for selecting the heat exchanger length and heat capacity ratio to obtain the effectiveness required in a hydrogen liquefaction system.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.481-486
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• 2021

Machine learning algorithms adopt criterion function as a key component to measure the quality of their model derived from data. Cluster analysis also uses this function to rate the clustering result. All the criterion functions have in general certain types of favoritism in producing high quality clusters. These clusters are then described by attributes and their values. Category utility and partition utility play an important role in cluster analysis. These are fully analyzed in this research particularly in terms of how they are related to the favoritism in the final results. In this research, several data sets are selected and analyzed to show how different results are induced from these criterion functions.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.868-870
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• 2005

임베디드 시스템의 신인도(Dependability)를 높이기 위해 기존 컴퓨터시스템에서 주로 사용되는 결함허용(Fault-tolerant) 기술을 그대로 적용시키는 것은 임베디드 시스템의 엄격한 비용 제약과 설치 공간의 부족 등의 이유로 적합하지 않다. 본 논문에서는 여분(Redundancy)을 최소 한도로 사용하는 차량 임베디드 시스템에 적합한 소프트웨어 결함허용 기법을 연구하였으며, 임베디드 시스템의 신인도를 반영할 수 있는 척도인 유용도(Utility) 척도를 정의하고, 임베디드 시스템의 결함허용을 위해 고려해야 할 각각의 재구성 조합에 대한 유용도 명가를 수행하였다. 이를 통해 차량 임베디드 시스템의 일부 부품이 결함 시, 가능한 최대의 유용도를 제공하는 구성조합으로 재구성 작업을 가능하게 하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.2
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• pp.65-72
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• 2007

As embedded system has strict cost and space constraints, it is impossible to apply conventional fault-tolerant techniques directly for increasing the dependability of embedded system. In this paper, we propose software fault-tolerant mechanism which requires only minimum redundancy of system component. We define an utility metric that reflects the dependability of each embedded system component, and then measure the defined utility of each reconfiguration combinations to provide fault tolerance. The proposed utility evaluation process shows exponential complexity. However we reduce the complexity by hierachical subgrouping at the software level of each component. When some components of embedded system are tailed, reconfiguration operation changes the system state from current faulty state to pre-calculated one which has maximum utility combination.

• (The) Korean Journal of Educational Psychology
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• v.28 no.1
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• pp.1-21
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• 2014

Two studies were conducted to investigate the interactive effect between temporal proximity of utility value and self-efficacy on situational interest and reengagement motivation. In study 1, university students were provided with either proximal or distal values of mental calculation task. Hierarchical regression analyses showed a significant interaction effect between distal utility value and high self-efficacy, indicating that distal utility value was more effective to induce situational interest and reengagement motivation for students with higher level of self-efficacy. In study 2, we replicated study 1 with high school students to investigate developmental differences and found the same results. These findings suggest that it is important to consider the level of self-efficacy and proximity of utility value in designing value intervention program.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.875-882
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• 2014

This paper aims to study on the relationship of u-Security service, usefulness and citizen satisfaction. Independence variable is u-Security service, a mediation parameter is usefulness, and dependent variable is citizen satisfaction. Using SPSS 18.0, a series of factor analysis, reliability analysis, multiple regression analysis and path analysis have been performed. The conclusion is as following. First, u-Security service affects usefulness. That is, as publicity safety, system quality, service quality increase, usefulness increases. Second, u-Security service affects citizen satisfaction. That is, as publicity safety, system quality, service quality increase, citizen satisfaction increases. Third, usefulness affects citizen satisfaction. That is, as economic usefulness and security usefulness increase, citizen satisfaction increases. Last, u-Security service has direct and indirect effect in usefulness and citizen satisfaction. That is, usefulness is an important variable that mediates u-Security service and citizen satisfaction.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.35-37
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• 2016

최근 IMO에서는 e-Navigation IT서비스를 사용자 입장에서 평가하도록 인간중심설계(HCD, Human Centered Design) 활동에 기반을 둔 유용성 평가에 대하여 표준화 작업을 진행하고 있다. 만약 IT서비스를 유용성 평가 기법으로 수행한다면 문제점, 오류, 개선사항, 사용자 요구사항 등을 도출할 수 있다. 그러나 IT서비스에 대한 유용성 평가의 관련 연구는 거의 진행되지 않고 있다. 이유는 최근 국제표준 제정을 준비하고 있고 평가를 위한 도구 및 평가 척도, 방법에 대한 기준이 명확하지 않기 때문이다. 따라서 본 연구에서는 경로 계획 공유(Route Plan Exchange) e-Navigation IT서비스에 대하여 유용성 평가 과정을 수행하였다. 유용성 평가를 위해 평가도구, 평가 시나리오, 평가 척도, 평가 방법을 개발하고 항해사 대상으로 유효성(Effectiveness), 효율성(Efficiency), 만족성(Satisfaction)을 평가하였다.

• Journal of KIISE:Information Networking
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• v.30 no.4
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• pp.535-544
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• 2003

Integrated services networks should guarantee end-to-end delay bounds for real-time applications to provide high quality services. A real-time scheduler is installed on all the output ports to provide such guaranteed service. However, scheduling algorithms studied so far have problems with either network utilization or scalability. Here, network utilization indicates how many real-time sessions can be admitted. In this paper, we propose service curve allocation schemes that result in both high network utilization and scalability in a service curve algorithm. In service curve algorithm, an adopted service curve allocation scheme determines both network utilization and scalability. Contrary to the common belief, we have proved that only a part of a service curve is used to compute deadlines, not the entire curve. From this fact, we propose service curve allocation schemes that result in a constant time for computing deadlines. We through a simulation study that our proposed schemes can achieve better network utilizations than Generalized processor Sharing (GPS) algorithms including the multirate algorithm. To our knowledge, the service curve algorithm adopting our schemes can achieve the widest network utilization among existing scheduling algorithms that have the same scalability.