• Fibers and Polymers
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• 제2권2호
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• pp.71-74
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• 2001

Surface characterization of materials has been considered critical in the development of biomaterials, as many unfavorable responses from the body occur at the interface between a material and the body component. The contact angle measurement is one means to characterize the surface properties and to correlate them to the biocompatibility of materials. In this paper, surface characteristics of silk fibroin/S-carboxymethyl kerateine, representative fibrous proteins, were investigated by contact angle measurements of ESCA. The biocompatibility of the blends was evaluated based on minimal interfacial free energy concept, and compared with other potential biomaterials. It was also hypothesized that the enhanced surface polarity of the blends was generated from the conformational transition of proteins. This approach to evaluate the biocompatibility of materials based on surface characteristics may find wide utility in many biomedical applications.

• 무역상무연구
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• 제27권
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• pp.99-127
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• 2005

This research can be summarized as follows: a. It provides the means how to manage risks in the electronic commerce with a focus on the insurance by which to transfer the risks to the third person. b. Since there are few preceding studies on the insurance of electronic commerce, further studies on the insurance stipulations about coverage and exclusions are needed. c. The risks in the electronic commerce are critical to the businessmen and the insurance can protect them from the perils and activate the electronic commerce. d. Inter-governmental and inter-organizational cooperations are needed to enact the unified international insurance clause. Researches on the electronic insurance should be vitalized for more objective analysis. A positive study needs a close survey on the individual and the business concerned, the insurance company, and the policy authorities, which will make it possible to adjust the coverage and exclusion and assess an optimum insurance rate.

• International Journal of Internet, Broadcasting and Communication
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• 제8권1호
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• pp.64-68
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• 2016

These fields are integrated to visualize and finalize the proposed development, in simulation environment. SCADA (supervisory control and data acquisition) systems and distributed control systems (DCSs) are widely deployed in all over the world, which are designed to control the industrial infrastructures, in real ways. To supervise and control the various parts of designed systems; trends to require a deep knowledge to understand the overall functional needs of industries, which could be a big challenge. Industrial field devices (or network sensors) are usually distributed in many locations and are controlled from centralized site (or main control center); the communication provides various signs of security issues. To handle these issues, the research contribution will twofold: a method using cryptography is deployed in critical systems for security purposes and overall transmission is controlled from main controller site. At controller site, multimedia components are employed to control the overall transmission graphically, such as system communication, bytes flows, security embedded parameters and others, by the means of multimedia technology.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.484-490
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• 2000

The freight wagon with weld fabricated 1-piece bogies, which was developed to increase operating speed, reveals its difficulties in maintenance. The weld-fabricated bogies were composed of two-stage coil spring and dry friction damping mechanism. The inborn wear parts and rather complicated structure mattes bogie maintenance difficult. In order to relieve this difficulties, the application of maintenance free rubber suspension is proposed by bogie maunfacturer, Taeyang Precision Limited. This study was conducted to determine design parameters of proposed rubber suspension by means of vehicle dynamic simulation and parametric study. The target critical speed of bogie was set over 150km/h for the preparation of further speed-up of freight wagon.

• 산업경영시스템학회지
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• 제17권32호
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• pp.227-232
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• 1994

In the performance domain, physical performance is a measure that represents some degree of system, subsystem, component or device success in a continuous sense, as opposed to a classical binomial sense (success or failure). If applicable sensing and monitoring means exist, physical performance can be observed over time, along with explanatory variables or covariables. Performance-based reliability represents the probability that performance will remain satisfactory over a finite period of time or usage cycles in the future when a performance critical limit (which represents an appropriate definition of failure in terms of performance) is set at a fixed level, based on application requirements. In the case of inadequate knowledge of the failure mechanics, this physical based empirical modeling concept along with performance degradation knowledge can serve as an important analysis tool in reliability work in product and process improvement.

• 에너지공학
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• 제23권4호
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• pp.183-188
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• 2014

Solenoid operated electromagnetic control valve (ECV) using in an external variable displacement swash plate type compressor is widely used for air conditioning control system because of its low energy consumption and high efficient characteristics. ECV controls the entire vehicle air conditioning system by means of a pulse width modulation (PWM) system that supplied from an external controller. Different pressure ports located within ECV has important functions to control the air/refrigerant flow through its internal passages. The flow paths are preciously maintained with acceptable ranges of leakage (gap) between the parts inside it which is followed by effective design and critical dimensioning of its internal features. Therefore, it saves energy losses from the solenoid operation as well as ensures the balance of forces within it. The research paper highlights analysis of the leakages (at different pressure ports) and dimensioning tolerance factors that affects the ECV performance.

• 공학교육연구
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• 제18권6호
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• pp.57-63
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• 2015

The purpose of this paper is to find a method to combine engineering education and the humanities by means of the movie genre. Although the science technology has developed and our living standard has improved, humanities has a tendency to be underestimated. Humanities has been treated as something antiquated, uninteresting or worn-out because it has no economic value or usefulness in itself. Engineering students need flexible, analytic and critical thought as well as the qualities in constructing key questions and trying to solve themselves. Communicative and understanding abilities are also required to them. Movies as a constructive visual device show problems with the reality. Especially, the science-related movie genre offers them an opportunity to think over why humanities matters as well as what matters in human being. The movies make engineering students think, discuss and argue on the humanity.

• 품질경영학회지
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• 제25권1호
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• pp.156-172
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• 1997

FMEA is a widely used technique to assess or to improve reliability of products at early stage of design and development. In order to implement FMEA effectively, it is important to utilize knowledge or technical know-hows. However, that is very difficult. In fact, if information on the failure modes is enough, it is important to consider a counterplan to eliminate critical failure modes. If engineers do not have such information, however, it is more important to know what failure modes of the component under consideration would undergo. This means that the purposes of performing FMEA varies according to the situation. Therefore, we need different kinds of FMEA charts to meet those purposes. This paper proposes two FMEA charts: one is suitable for detecting potential failure modes and the other is for product improvements.

• 품질경영학회지
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• 제22권4호
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• pp.132-151
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• 1994

Quality is a critical competitive factor in today's environment because of the impact of quality on market share, productivity and costs. Especially in Korean companies, the importance of quality is heightened as they are losing price competitiveness compared to the new industrialized countries. The traditional approach to quality improvement has been focused on workers. The primary means to achieving acceptable outgoing quality has been to inspect quality by adding more inspectors and inspection stations. This is an example of quality cost that can be reduced through the preventive actions against bad quality. Quality cost is best viewed as a measure of costs specifically associated with the achievement or nonachievement of product/service quality required by customers. This paper examines the concept of quality cost, provides guidance to implementing a quality cost system, and identifies the limitations of quality cost information. These limitations are the target for future research for an efficient and effective implementation of quality cost system.

• 한국소음진동공학회논문집
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• 제15권4호
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• pp.388-394
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• 2005

This paper has the object of investigating natural frequencies of tapered thick plate on Pasternak foundation by means of finite element method and providing kinetic design data for mat of building structures. Vibration analysis for tapered thick plate subjected to in-plane stress is presented in this paper. Finite element analysis of rectangular plate is done by use of rectangular finite element with 8-nodes. Analysis conditions of tapered thick plate are as follows each. The ratio of in-plane stress to critical load is varied with $0.2\sigma_{cr}$, $0.4\sigma_{cr}$, $0.6\sigma_{cr}$. The Winkler parameter is 0, 10, 100, 1000, the shear foundation parameter is 0, 10 and the taper ratio is 0.0, 0.2, 0.4, 0.6, 0.8.