• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.3
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• pp.33-42
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• 2011

This study focused to find the main factors causing job stress to ROKAF pilots and of which factors affects to turnover intention. As a results, the factors of job stress are job characteristics, over loaded ground work, payment, promotion and employee benefits & service system. All of these 5 factors are positively related to the causes of a pilot stress. Among the job stress factors, payment, promotion and over loaded ground work are positively related as the same order. But, job characteristics and employee benefits & service system are not. Even though ROKAF pilots are stressed by annual requirement and night flying, and also are stressed by unfulfilled welfare, those two stress factors are not related to the turnover intention.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.179-182
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• 2009

PSS (Product-Service Systems) 개발에 있어서 중요한 요소로서 사용자의 경험을 들 수 있다. 제품개발 시 가장 중요하게 고려되는 요소로서 고객의 요구 (customer requirement)와 니즈 (needs)가 언급되곤 한다. 고객의 요구나 니즈는 실제로 관련 제품이나 서비스를 사용해 본 고객의 경험에 근거하고 있다. 따라서 고객의 경험을 제대로 파악하고 이를 추출하는 것이 성공적인 제품개발의 시작이다. 본 연구의 목적은 사용자 경험을 활용하는 제품-서비스 시스템 (UXPSS)을 위한 프레임워크 모델을 개발하고 샘플 제품에 대한 구현을 실시한다. 이를 위해서 사용자 경험, 제품의 서비스화, 서비스의 제품화, 서비스 사이언스, 기능분석 및 모듈화를 결합한 통합 모델을 개발하고 이를 실험적으로 구현해 본다.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.6 no.2
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• pp.9-15
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• 2010

US NRC issued rulemaking of 10CFR50.55a to perform the Perservice and Inservice inspection for Reactor Vessel Head Penetration Nozzle of US Nuclaer plant. The rulemaking was required the EPRI Demonstration to verify the NDE technique performing special Ultrasonic examination. In order to meet this requirement, the UT and ECT procedures was demonstrated and the NDE personnel were qualified by EPRI. In this paper, the NDE technique and analysis method are described the Preservice inspection for the Palo Verde #1/2/3 Replacement Reactor Vessel Head Penetration Nozzle using the qualified procedures and personnel.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.886-891
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• 2018

Colloid silica using as abrasive for polishing sapphire has been extensively studied, which mechanism has also been deeply discussed. However, by the requirement of application enlargement and cost reduction, some new problems appear such as silica service life time, particle diameter mixing, etc. In this paper, several influences of colloid silica usage on sapphire CMP are examined. Results show particle diameter and concentration, pH value, service life time, particle diameter mixing heavily influence removal rate. Further analysis discloses there are two main effect aspects which are quantity of hydroxyl group, contact area for abrasive density stacking between abrasive and sapphire. Based on the discussions, a dynamic process of sapphire polishing is proposed.

• ETRI Journal
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• v.26 no.1
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• pp.48-52
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• 2004

In this letter, we consider a new packet scheduling algorithm for an orthogonal frequency division multiplexing access/frequency division duplex (OFDMA/FDD)-based system, e.g., mobile broadband wireless access or high-speed portable internet systems, in which the radio resources of both time and frequency slots are dynamically shared by all users under a proper scheduling policy. Our design objective is to increase the number of non-realtime service (e.g., WWW) users that can be supported in the system, especially when the minimum bit rate requirement is imposed on them. The simulation results show that our proposed algorithm can provide a significant improvement in the average outage probability performance for the NRT service, i.e., significantly increasing the number of NRT users without much compromising of the cell throughput.

• Journal of Industrial Technology
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• v.27 no.B
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• pp.77-82
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• 2007

A novel DDoS (Distributed Denial-of-Service) defense technique, Exaustiveness-Based Detection, is proposed in this work. It dispenses with the network congestion and the unfairness between users of the Defense-by-Offense technique by incorporating a kind of simple Detect-and-Block scheme (user identification), still improving the effectiveness of the defense in comparison to the original Defense-by-Offense technique. It uses SYN cookies to identify users in the granularity of ip address and to prevent ip address spoofing by the attacker. There can be, however, some probability of false negative (denying service to good clients), if the attacker wisely adapt to the new technique by saving some portion of its bandwidth resource and later mimicking good clients. Quantitative analysis the requirement for the good clients to be safe from the false negative is provided and a procedure to design the server capacity is explained.

• Journal of the Korea Safety Management & Science
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• v.13 no.3
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• pp.97-105
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• 2011

In order to determine home delivery service routes, conditions specified for each parcel such as customer-assigned delivery times and parcel contents should be considered, so the conventional route search algorithms have some limits to be applied for home delivery services. In this study, a multi-purpose route searching algorithm is suggested in order to deal with every requirement of deliveries that vary in delivery distances, contents and appointed times. A simulation study to verify the performances of the system with example data of Seoul and Kyungki provinces shows that it significantly improves the customer satisfaction and the productivity of delivery businesses.

• Journal of Digital Contents Society
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• v.4 no.2
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• pp.181-189
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• 2003

The requirement of distributed multimedia applications is the need for sophisticated QoS(quality of service) management. In terms of distributed multimedia systems, the most important catagories for quality of service are a timeless, volume, and reliability In this paper, we discuss a method for increasing reliability through fault tolerance. We describe the design and implementation of the ECA running on distributed multimedia environment. ECA is a system is able to classify automatically a software error based on distributed multimedia. This papaer explains a performance analysis of an error classification system running on distributed multimedia environment using the rule-based DEVS modeling and simulation techniques. In DEVS, a system has a time base, inputs, states, outputs, and functions.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.3
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• pp.51-62
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• 2013

We propose a method using QFD for design the hierarchical structure of AHP. This method provides definition for each area of House of Quality and design the hierarchical structure of the bottom-up QFD/AHP in which the upper hierarchy is designed through the classification of common characteristics with a focus on the lower hierarchy. Finally, we apply it to the development of an evaluation index for selecting heavy lifting service providers. This study has significance as the first instance of designing the archical structure of AHP after objectively verifying whether MECE condition, the basic requirement for AHP design, is satisfied.

• Magazine of the Korean Society of Agricultural Engineers
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• v.8 no.1
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• pp.1071-1076
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• 1966

In this country grassed waterway practice has long been employed for the protection of drainage or diversion ditches in treating the sloped forest lands. However, the hydraulic characteristics of flow in the ditches have been entirely away from consideration in determining the dimensions of the ditches. This paper is intended first to bring forth some problems which should be brought ioto Consideration in designing grassed waterway including hydrologic aspect for determining the drainage requirement, erosion resistance of various grasses and other factors related to the hydraulics of ditch and second to introduce to readers a method of grassed waterway design, though modified, proposed for U. S. Soil Conservation Service practice. The method presented in the paper was primarily based upon the data originated from the experiments of U. S. Soil Conservation Service laboratories and further investigations on the factors involved are hoped to be conducted for applying the design criteria in this country. It is recommended to use the method of grassed waterway design ,presented in this paper from the view point of wide employment of grass lining on ditches which is obtainable at the lower cost and in abundance every where in this country.