• 한국시뮬레이션학회논문지
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• 제15권2호
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• pp.51-57
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• 2006

현재 반도체 산업은 200mm 웨이퍼에서 300mm 웨이퍼 공정으로 기술이 변화하고 있다. 300mm 웨이퍼 제조업체들은 Fabrication Line (FAB Line) 자동화를 비용절감 실현의 방책으로 사용하고 있다. 또한 기술의 확산, 시장 경쟁력의 격화 등으로 생산성 향상에 의한 원가절감이 반도체 산업 성장의 근본요인이 되고 있다. 대부분의 반도체 업체들은 생산성을 높이기 위해 average cycle time을 줄이는데 총력을 기울이고 있다. 본 논문에서는 average cycle time을 줄이는 데 중점을 두고, 300mm 반도체 제조공정을 시뮬레이션 하였다.

• 소음진동
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• 제10권4호
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• pp.686-691
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• 2000

In this paper a computer aided analysis method is proposed for durability assessment in the early design stages using dynamic analysis, stress analysis and fatigue life prediction method. From dynamic analysis of a vehicle suspension system, dynamic load time histories of a suspension component are calculated. From the dynamic load time histories and the stress of the suspension component, a dynamic stress time history at the critical location is produced using the superposition principle. Using linear damage law and cycle counting method, fatigue life cycle is calculated. The predicted fatigue life cycle is verified by experimental durability tests.

• Asia pacific journal of information systems
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• 제11권3호
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• pp.63-89
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• 2001

The purpose of this research is to develop strategic alternatives for the high-tech products development by comparatively studying characteristics of the industry and R&D structures in Korea and the US. Some of the environmental, strategic, organizational and project teams' characteristics are studied. Data were collected from Korea and US high-tech companies through interviews and questionnaires and event analysis method was used to analyze them. The findings are as follows: First, when the level of market concentration is high, cycle time tends to be longer. Therefore, if there are many competitors in the market, new products development should be swift due to competitive pressures. Second, the developmental strategy should be directed toward the existing customers to speed up new products development. That is, a defensive strategy would result in a shorter cycle time and response time compared to a strategy directed to a niche market. Third, when the level of formalization is high, cycle time tends to be shorter. This means that formal procedures for new products idea development or new products development policies shorten new products development time.

• 대한한의학원전학회지
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• 제22권3호
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• pp.271-289
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• 2009

This thesis intend to help the eastern medical doctor to understand body condition from interpretation of perspirations(汗出) in daily time cycle. The conclusion is followed. 1. In most Eastern Medical classic and clinic literatures, the time of fever and perspirations are described as a result of disease's position at human body. Following this description, in daytime the perspirations must come from the Gi phase and night time the perspirations must come from the blood phase. Because in daytime the skin pores are opening and the defensive Gi is going out to the superficial portion of the body. In night time the skin pores are shutting and the defensive Gi is going in to the five solid organs. So a sweat in daytime comes out from the Gi phase and superficial portion of the body. And in night time comes out from the blood phase and five solid organs. But in recent real clinic cases, in daytime, there are so many perspirations from the five solid organs. Comparatively, the perspirations from the superficial portion of body are very little. And in same daytime perspirations, when the heat pathogens mixed with moist, the symptom revelation time delay to the afternoon. Therefore it can be concluded that the time of perspirations are combination of disease's Gi or blood phase and characteristics of pathogens. The position of disease at human body cannot simply judge the symptom revelation time. 2. The exchange of climate following time cycle of a day effect to the condition of human body. At same time it activates or not activates the pathogens in human body. So we can consider the kinds and characteristics of pathogens by distinguishing the symptom revelation time. In general differentiation of syndromes[辨證] pathogen's kinds and location are generally judged. By understanding the characteristics of pathogen, doctor can devise more correct and delicate prescription.

• 대한교통학회지
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• 제30권3호
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• pp.71-82
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• 2012

본 연구는 통근자를 생애주기별로 구분하여 하루 동안 발생하는 통행시간에 미치는 요인을 분석하였다. 본 연구에서 통행시간이란, 통행사슬(Trip chain)개념을 적용하여 통근자가 집에서 출발하여 귀가할 때까지 하루 동안 일어나는 활동을 위해 이동하는데 소요된 시간의 합을 의미한다. 통근자의 생애주기는 가구주의 연령, 가족구성원의 유형을 근거로 미혼청년기, 가족형성기, 자녀교육기, 자녀청년기, 자녀독립기, 노년기의 6단계로 구분하였다. 생애주기별 통행특성은 통행시간, 사이클 수, 스톱수를 볼 때 차이가 있는 것으로 나타났다. 콕스비례해저드 모델을 적용하여 통행시간에 영향을 미치는 요인을 분석한 결과, 일부요인들은 생애주기별 통행시간에 영향을 미치는 것으로 나타났다. 본 연구는 실증적인 연구로써 경기도를 대상으로 하였으며, 자료는 2010년 가구통행실태조사 자료를 이용하였다.

• 천문학회지
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• 제50권2호
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• pp.21-27
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• 2017

The autoregressive method provides a univariate procedure to predict the future sunspot number (SSN) based on past record. The strength of this method lies in the possibility that from past data it yields the SSN in the future as a function of time. On the other hand, its major limitation comes from the intrinsic complexity of solar magnetic activity that may deviate from the linear stationary process assumption that is the basis of the autoregressive model. By analyzing the residual errors produced by the method, we have obtained the following conclusions: (1) the optimal duration of the past time for the forecast is found to be 8.5 years; (2) the standard error increases with prediction horizon and the errors are mostly systematic ones resulting from the incompleteness of the autoregressive model; (3) there is a tendency that the predicted value is underestimated in the activity rising phase, while it is overestimated in the declining phase; (5) the model prediction of a new Solar Cycle is fairly good when it is similar to the previous one, but is bad when the new cycle is much different from the previous one; (6) a reasonably good prediction of a new cycle can be made using the AR model 1.5 years after the start of the cycle. In addition, we predict the next cycle (Solar Cycle 25) will reach the peak in 2024 at the activity level similar to the current cycle.

• 한국분무공학회지
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• 제18권3호
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• pp.132-139
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• 2013

Smoke emissions from light duty diesel vehicles were measured using light extinction method with the free acceleration test mode. The smoke emissions for each measurement cycle of the free acceleration method showed large variations according to driver's pedal pushing pattern. The smoke values for each measurement cycle initially increased and reach a peak value. Integration of the smoke emissions with time for each measurement cycle was performed to get a representative smoke value which was obtained by averaging the integrated results. Two kinds of integration time range were used. One is range over the whole measurement cycle of the free acceleration method. The other is only the acceleration range in the measurement cycle. Overall, variation of the representative smoke values obtained by the integration method was reduced comparing to the traditional representative smoke value which was obtained from a peak smoke value over the measurement cycle. Ten vehicles of the same model with 2.5 liter diesel engines, and seven vehicles of the same model with 2.7 liter diesel engines, were tested using the free acceleration test method.

• 산업경영시스템학회지
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• 제43권1호
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• pp.61-69
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• 2020

Systems such as database and socal network systems have been broadly used, and their unexpected failure, with great losses and sometimes a social confusion, has received attention in recent years. Therefore, it is an important issue to find optimal maintenance plans for such kind of systems from the points of system reliability and maintaining cost. However, it is difficult to maintain a system during its working cycle, since stopping works might incur users some troubles. From the above viewpoint, this paper discusses minimal repair maintenance policy with periodic replacement, while considering the random working cycles. The random working cycle and periodic replacement policies with minimal repair has been discussed in traditional literatures by usually analyzing cases for the nonstopping works. However, maintenance can be more conveniently done at discrete time and even during the working cycle in real applications. So, we propose that periodic replacement is planned at discrete times while considering the random working cycle, and moreover provide a model in which system, with a minimal repair at failures between replacements, is replaced at the minimum of discrete times KT and random cycles Y. The average cost rate model is used to determine the optimal number of periodic replacement.

• 대한물리치료과학회지
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• 제18권3호
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• pp.33-39
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• 2011

Background : The purpose of this study was to apply cervical orthosis for temporal parameters of gait was to evaluate the effect. Methods : Seven normal adults participated in this study. Before and after applying a cervical orthosis compared to gait. Outcome measure were: general characteristics, temporal parameters of gait. General chacteristics included age, gender, height, weight. Temporal parameters included the Velocity cycle, Stride length, Step length, Cadence cycle, Initial double support time. Temporal parameters of gait, using the motion analysis system for cervical orthosis were evaluated before and after applying. The data was analyzed using SPSS 12.0 software and the Wilcoxon's signed-ranks test. Results : Velocity cycle and Step length were no significant differences(p>0.05). But Stride length, Cadence cycle, Initial double support time were significant(p<0.05). After apply Cervical orthosis in gait, Stride length and Initial double support time was decreased and Cadence cycle was increased. Conclusion : Changes in temporal of temporal parameters of gait was apply a cervical orthosis with the limitations of vision due to take effect. Therefore, Cervical orthosis does not interfere with the normal gait pattern by limiting the Range of Motion so that we consider to apply.

• 산업경영시스템학회지
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• 제28권3호
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• pp.75-86
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• 2005

To investigate the fatigue characteristic of upper limbs, this study analyzed RMS(root mean square) and MPF(mean power frequency) value between initial and terminal stages of each experiment condition. And the effect of intermittent endurance time was evaluated using the Borg's CR10 value that was measured for the parts of upper limb. According to the results of ANOVA on RMS value, there were significant difference on the %MVC about push, pull, and down force exertion. Particularly the ANOVA of up force exertion was significant difference on shoulder flexion, elbow flexion and rest time as well as %MVC. The results of ANOVA for MPF value were significant difference on the %MVC in regard of the push and up force exertion. In case of up force exertion, MPF value tended to shift low frequency at all of the experiment conditions. According to the analysis of duty cycle, RMS value considerably increased over 50% duty cycle and as the %MVC increased, the duty cycle affected the increase of RMS value. MPF value for up and down force exertion decreased at 33%, 50% and 67% duty cycle for all of %MVC. Borg CR10 value of hand and forearm were below the 3-point to the 40% of endurance time at 30%MVC and to the 20% of endurance time at 50%MVC with the exception of up force exertion. But Borg CR10 values of upper arm and shoulder at up force exertion were more than 3-point to the 20% of endurance time at 30%MVC and in the start point of endurance time at 50%MVC.