• 대한기계학회논문집A
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• 제29권2호
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• pp.262-269
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• 2005

Optimization of a satellite structure under severe space launching environments is performed considering various design constraints. Simulate annealing, one of combinatorial optimization techniques, is used to optimize the satellite. The optimization results by the simulated annealing are compared to those by the method of modified feasible direction and genetic algorithm. Ten bar truss structure is optimized for feasibility study of the simulated annealing. Finally, the satellite structure is optimized by the simulated annealing algorithm under space environment. Weights of the satellite upper platform and propulsion module are minimized with consideration of several static and dynamic constraints. MSC/NASTRAN is used to find the static and dynamic responses. Simulated annealing has been programmed and integrated with the finite element analysis program for optimization. It is shown that the simulated annealing algorithm can be extended to the optimization of space structures.

• 산업경영시스템학회지
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• 제19권40호
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• pp.119-136
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• 1996

With new competitive environments, innovation is more necessary to survive severe competitions than ever. However, most Small and Medium(SM) businesses are used to be short of professional staffs, money and equipments for performing various innovations(ie., technological or administrative innovation, product development or Process development, and radical or incremental innovation). Many students have suggested that incremental innovation is more adequate than radical innovation in SM business. The purpose of this paper is to find antecedent factors In promote employees' Incremental Innovation Activities(IIA), In analyse moderating effects of ability and attitudes, and to test the difference of IIA-level by ability(or attitudes) and 11 independent factors. Each IIA-level by 5 variables of 11 independent variables-job variety, importance, identity, communication, performance dependency-is found to be significantly different in high-ability group affirmative-attitude group.

• 한국멀티미디어학회논문지
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• 제23권5호
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• pp.683-699
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• 2020

Recently, the earth's highest temperature is rising due to severe climate change and heat wave. In addition, due to the increase of elderly population over 65, the number of heat patients is also increasing. In particular, the elderly who live alone in poor living environments, the lower income group, and the socially disadvantaged, such as children and pregnant women, are exposed to the dangers of heat waves, so the government's practical measures are urgently needed. In this study, we will build a visualization platform for each level of heat wave and provide the necessary countermeasure solution according to the heat wave risk. "The Hazard Visualization Platform for Heatwave" provide not only simple information, but also a customized safety service for citizens to prevent heatwaves, respond to heatwaves, and utilize heat wave information.

• Journal of Power Electronics
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• 제9권5호
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• pp.748-756
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• 2009

This paper presents a compensation algorithm for position error due to an amplitude imbalance between resolver output signals. Resolvers are typically used to obtain absolute position information for motor drive systems in severe environments. Position error is caused by an amplitude imbalance of the resolver output signals. As a result, the d- and q-axis currents of synchronous reference frame have periodic ripples in the stator fundamental frequency in permanent magnet synchronous motor (PMSM) drive systems. Therefore, this paper proposes a compensation algorithm to reduce the position error generated by the amplitude imbalance. The proposed method does not require any additional hardware, and reduces computation time with a simple integral operation according to rotor position. In addition, the position error can be directly compensated for by the estimated position error. The effectiveness of the proposed compensation algorithm is verified through several simulations and experiments.

• 한국농공학회논문집
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• 제54권6호
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• pp.121-131
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• 2012

Many of the falling which is the number one risk factor in lethal accidents in construction could have been prevented if the right activity or supervising had been taken in time. All other measures do not preventive the fall, but rather intercept the fallen itself or preventive severe injury. The most common and the bets measures on the preventive measures are guardrails which are to be worn on the site. Workers always exposed the risk of serious accidents induced by causal effects related with environments around construction sites. In order to represent how to decrease the risk of workers, this study was accomplished with a number of interview with experienced site director, cheief of instructors, workers. And the questionaire survey (2012. 5~2012. 10) were used to make proposed policies which are expected to reduce critical disastrous accidents and strength authorized limits of director's management automatically.

• 한국IT서비스학회지
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• 제8권4호
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• pp.41-55
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• 2009

Due to the global business environments and severe competitions, SMEs have carried out IS projects for their competitive advantages. However, numerous organizations have faced with difficulties in the IS project management such as large amounts of IT expenses and uncertainties in project implementations. Thus, this study is intended to discover critical risk factors in the IS project management. To achieve this research goal, we have mailed questionnaires to SMEs and SI companies that experienced IS project failures and 63 usual data were collected. The result of analysis with step wise regression showed that 6 factors are related with IS project failures. The study contributes to the literature in two ways. First, this paper empirically identifies IS risk factors for SME manufactures. Second, this research result can be utilized as a checklist for the successful IS implementations. Limitations and future research topics are also discussed.

• 한국정보시스템학회지:정보시스템연구
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• 제20권3호
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• pp.25-40
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• 2011

Small and Medium sized hospitals are exposed to severe managerial environments recently. Around 8.0% of the hospitals are bankrupted every year. The adverse managerial environment does not only come from external factors such as patients' preference for larger hospitals, regulations on the medical charges; more serious problems come from the way the medium and small sized hospitals deal with those exogenous changes including lack of management skills, lack of change management skills, lack of managerial decision support systems, etc. This paper aims to support managers to make decisions regarding the exogenous changes. This paper can be interpreted as an attempt of a merge of the two techniques; BSC and system dynamics. Starting with a BSC system, the development of a system dynamics model can take advantages of the BSC information.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.553-556
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• 2006

Generally, concrete is one of the most widely used construction materials, because of its good durability to cost ratio. However, when subjected to severe environments its durability can significantly decline due to various harmful conditions. In this article, we would like to investigate a chloride ion diffusion of cement matrix with inert filler, which ground calcium carbonate(GCC). For the experimental results of the chloride ion diffusion, as the addition of GCC makes decreasing the permeability by micro-filler effect, the matrix of 5-15% ratio of replacement are superior to the GCC0 mortar matrix with respect to durability of cement matrix in this scope.

• KDI Journal of Economic Policy
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• 제38권4호
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• pp.23-44
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• 2016

Household debt in Korea raises concerns about the resilience of the economy due to its size and quality. Against this backdrop, we investigate if household leverage matters for private consumption in adverse economic environments even without severe financial disruptions. We find that the balance sheet positions in terms of the leverage ratio may weaken consumption growth. We also find that the depressive effect of debt on consumption may differ across types of consumer spending and household characteristics. In particular, the effects of indebtedness have been much stronger in relation to durable goods expenditures than in other areas. In addition, debtors in high-income (wealth) groups have also shown downward adjustments in consumption even more so than low-income (wealth) groups. These findings imply that debtors' precautionary behavior may serve as an important channel from leverage to consumer spending.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.421-423
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• 2005

Power transmission lines have been playing a key role as the mainstay of national industry. When a power failure occurs, it can have severe effects on national security as well as national industry and economy. In this paper, we consider an insulator failure, which is one of the main causes of such a power failure. In spite of its importance, however, a shortage of manpower in the insulator maintenance field is getting more serious due to working environments with a high voltage and a high place. For this reason, a new active maintenance technique using a robot system is required to prevent such an insulator failure. In this paper, a new robot mechanism for insulator cleaning and inspection was developed. We confirmed its effectiveness through experiments.