• 품질경영학회지
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• 제20권2호
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• pp.44-54
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• 1992

In conventional fault-tree analysis, the failure probabilities of components of a system are treated as exact values in estimating the failure probability of the top event. For the plant layout and systems of the products, however, it is often difficult to evaluate the failure probabilities of components from past occurences, because the environments of the systems change. Furthermore, it might be necessary to consider possible failure of components of the systems even if they have never failed before. In the paper, instead of the probability of failure, we propose the possibility of failure, viz, a fuzzy set defined in probability space. Thus, in this paper based on a fuzzy fault-tree model, the maximum possibility of system failure is determined from the possibility of failure of each component within the system according to the extension principle.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 1999년도 제16회 동계학술발표회 논문집
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• pp.328-347
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• 1999

The substitution of Electronic Commerce(EC) for the traditional transactions triggers the changes of the industry structures and promotes the cost reductions of the firms in the areas of distributions and other administrative operations associated with purchase via EC. Our study clarifies the changes of the environments attributable to EC which are faced inter-and-externally by firms and try to exhibit the trend of EC market growth through such descriptions. Regardless of the rapid spread of EC, recent studies do not show appropriately its impact on the relevant industries and our domestic economy. Therefore, our study focuses on the forecasting of the impacts of EC on the domestic productions and imports. To this end, we develop an analytic framework using the existing data in Input/Output Analysis and the estimations of the EC market growth in the future. We, finally, identify the industrial sectors whose productions and imports are estimated to be accelerated by the extension of EC and forecast the whole effects of EC on domestic productions and imports.

• 대한안전경영과학회지
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• 제5권2호
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• pp.53-66
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• 2003

This study analysed the result of a survey answered by 120 technology teachers and 360 students from 357 middle schools in Seoul to find out the actual state of safety accidents during technology education activity course in the middle school class and safety awareness of the teachers and students. The result shows that many safety accidents happen during technology education activity course in the middle school class. However, most teachers and students have experienced safety accidents or dangerous situations more than once a year. Technology teachers had very low awareness on the states of retaining safety equipments. On the other hand, they were well aware of the importance of safety, including the actual states of safety education, knowledge of safety, and the will to join safety education. Therefore, safety awareness of technology teachers should be reinforced by the extension of safety training and the improvement of safe environments.

• Journal of Advanced Marine Engineering and Technology
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• 제17권3호
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• pp.42-49
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• 1993

Recently, because the lubricating oil showed a tendency to be emulsified and oxidized by high speed, high output and the extension of maintenance & conservation of marine engine, the cavitation erosion-corrosion at such an environment became a big problem on effective performance of engine. Therefore, there was a need to study the behavior and protection of erosion-corrosion damage, and then applied inhibitor to a protective method of cavitation erosion- corrosion damage. At this time, test environments were marine lubricating oil & various emulsified oil that mixed distilled water and sea water etc., and also used 20KHz, 24.mu.m piezoelectric vibrator as an experimental apparatus of cavitation erosion. With this apparatus, we investigated an influence of the emulsified oil on characteristics of erosion-corrosion and protection for erosion-corrosion by inhibitor at slide bearing metals.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.891-891
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• 2002

Currently there are numerous papers in which many new kinds of customizing stereotypes by UML extension mechanism for different application environments such as real-time system, Geographic Information System (GIS) and so on are proposed. However , these stereotypes that represent different type model elements such as class, association, generalization and so on have not yet been seen in one of the most popular visual modeling tool for software development, Rational Rose. Therefore, in this paper, a design of extended iconic stereotype for GNSS application in the UML class diagram and its implementation as a tool of StereotypeCreator for Rational Rose will be presented.

• 대한산업공학회지
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• 제23권3호
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• pp.559-580
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• 1997

It is essential to construct on efficient material flow system for the successful introduction of automated manufacturing systems. Automated Guided Vehicle System(AGVS) ploys a significant role more and more in modern manufacturing environments, because of the flexibility and the precision they offer. However, as the size and the complexity of systems increase, the problems of dispatching, routing and scheduling of AGVs became complicated due to their independent and asynchronous demands. In this paper, we review relevant papers, and provide a new and more efficient method for partitioning the AGV system by introducing the concept of Central Path. This method named Central Path design has advantages, since each partitioned workstation group is served by one AGV and the material handling between groups is performed by special AGV that is used for the Central Path. Therefore the congestion problems never occur. Furthermore Central Path Design has a high flexibility for alteration and extension of system. Finally, we demonstrate its efficiency using simulation.

• 로봇학회논문지
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• 제19권1호
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• pp.1-7
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• 2024

This paper presents an under-actuated robotic hand inspired by the ligamentous structure of the human hand for a prosthetic application. The joint mechanisms are based on the concept of a tensegrity structure formed by elastic strings. These rigid bodies and elastic strings in the mechanism emulate the phalanx bones and primary ligaments found in human finger joints. As a result, the proposed hand inherently possesses compliant characteristics, ensuring robust adaptability during grasping and when interacting with physical environments. For the practical implementation of the tensegrity-based joint mechanism, we detail the installation of the strings and the routing of the driving tendon, which are related to extension and flexion, respectively. Additionally, we have designed the palm structure of the proposed hand to facilitate opposition and tripod grips between the fingers and thumb, taking into account the transverse arch of the human palm. In conclusion, we tested a prototype of the proposed hand to evaluate its motion and grasping capabilities.

• 대한수학교육학회지:수학교육학연구
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• 제12권3호
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• pp.331-351
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• 2002

It is widely recommended that teachers should actively mediate students' engagement with tools such as manipulative materials. This paper is to help to parse classroom life so that both social and psychological aspects are accounted for and coordinated. Building on the theory of affordances from ecological psychology and the activity theory from sociocultural perspectives, the main strategy of this paper is to view manipulative materials as simultaneously participating in social and psychological activity systems. Within these activity systems it is charted how both mathematical affordances related to the structure of mathematical concepts and ecological affordances related to socially situated classroom practices need to be considered by teachers in effective mediation of mathematical manipulatives. This paper has three major sections. The first section develops a theoretical extension of Gibson's theory of affordances from natural to social environments. The second section introduces mathematical and ecological affordances using empirical data from a grade two elementary school classroom. The third section illustrates the need of coordinating the two affordances as embedded in different activity systems.

• The Journal of the Acoustical Society of Korea
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• 제15권1E호
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• pp.39-44
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• 1996

Matched field localization schemes often show a high sensitivity to acoustic variabilities due to mismatch between assumed and actual environments. In this paper, we focus on the effect of source motion or Doppler on matched field processing (MEP). to accomplish this, MFP is extended to treat a moving source problem with normal mode description of the sound field. the extension involves both the temporally nonstationary and spatially inhomogeneous nature of the sound field generated by a time-harmonic point source moving uniformly in a stratified oceanic waveguide. It is demonstrated that the impact of source motion can be significant to MEP although the velocity of a moving source is much smaller than the sound velocity of the oceanic waveguide. In addition, a criteria for minimizing the effect of Doppler on MFP is discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1713-1715
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• 2007

Measurement of network traffic have shown that the self-similarity is a ubiquitous phenomenon spanning across diverse network environments. In previous work, we have explored the feasibility of exploiting the long-range correlation structure in a self-similar traffic for the congestion control. We have advanced the framework of the multiple time scale congestion control and showed its effectiveness at enhancing performance for the rate-based feedback control. Our contribution is threefold. First, we define a modular extension of the TCP-a function called with a simple interface-that applies to various flavours of the TCP-e.g., Tahoe, Reno, Vegas and show that it significantly improves performance. Second, we show that a multiple time scale TCP endows the underlying feedback control with proactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of the three traffic control dimensions-tracking ability, connection duration, and fairness-on performance.