• 센서학회지
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• 제5권4호
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• pp.47-56
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• 1996

속도제어루프내에서 외란의 각속도를 감지하여 짐발을 안정화시키기 위해 사용하는 동조자이로스코프에 대한 기본원리 및 특성을 분석하였다. 또한 비례모드 자이로스코프의 모델을 정확하게 제시하였으며, 제시된 모델은 공진 특성을 가지고 있기 때문에 기존에 사용하고 있는 2차 시스템 모델보다 실제 시스템의 특성과 유사하므로 일반적인 비례모드 자이로스코프에서도 적용 가능하다. 실제 시스템인 전자광학추적기에 사용할 경우 발생되는 문제점을 알아보고 그 해결 방안을 제시하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권4호
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• pp.277-293
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• 2016

We develop an efficient numerical method for pricing the Derivative Linked Securities (DLS). The payoff structure of the hybrid DLS consists with a standard 2-Star step-down type ELS and the range accrual product which depends on the number of days in the coupon period that the index stay within the pre-determined range. We assume that the 2-dimensional Geometric Brownian Motion (GBM) as the model of two equities and a no-arbitrage interest model (One-factor Hull and White interest rate model) as a model for the interest rate. In this study, we employ the Monte Carlo simulation method with the Compute Unified Device Architecture (CUDA) parallel computing as the General Purpose computing on Graphic Processing Unit (GPGPU) technology for fast and efficient numerical valuation of DLS. Comparing the Monte Carlo method with single CPU computation or MPI implementation, the result of Monte Carlo simulation with CUDA parallel computing produces higher performance.

• Geomechanics and Engineering
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• 제21권3호
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• pp.237-245
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• 2020

The process of evaporation from free water surface was simulated in a large scale environmental chamber under various controlled atmospheric conditions and also was modelled by a new mass transfer model. Six evaporation tests were conducted with increasing wind speed and air temperature in the environmental chamber, and hence the effect of atmosphere parameters on the evaporation process and the corresponding response of water were investigated. Furthermore, based on the experiment results, seven general types of mass transfer models were evaluated firstly, and then a new model consisted of wind speed function and air relative humidity function was proposed and validated. The results show that the free water evaporation is mainly affected by the atmospheric parameters and the evaporation rate increases with the increasing air temperature and wind speed. Both the air and soil temperatures are affected by the energy transformation during water evaporation. The new model can satisfactorily describe the evaporation process from free water surface under different atmospheric conditions.

• Journal of applied mathematics & informatics
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• 제16권1_2호
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• pp.195-205
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• 2004

To the unconstrained programme of non-convex function, this article give a modified BFGS algorithm. The idea of the algorithm is to modify the approximate Hessian matrix for obtaining the descent direction and guaranteeing the efficacious of the quasi-Newton iteration pattern. We prove the global convergence properties of the algorithm associating with the general form of line search, and prove the quadratic convergence rate of the algorithm under some conditions.

• 한국경영과학회지
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• 제7권1호
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• pp.31-43
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• 1982

A general equilibrium growth model is constructed to analyse the income distributional impacts of the 1973 world oil crisis upon the Korean economy. Our results show that all consumer groups experienced a virtually uniform percentage reduction in their income levels. This implies that a lower income groups may be more damaged in a relative sense. In any rate, there were no domestic groups who benefit from the international oil crisis. This model could be used to figure out which social group will be most vulnerable against the next possible oil crisis we may expect in the future. Our result nay provide us a guideline for a compensating program to protect such groups against an external shock.

• Asian Journal of Innovation and Policy
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• 제8권1호
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• pp.97-121
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• 2019

The Korean government has focused on universities or colleges as the main targets of its startup policy since the 2010s. However, the performance is not so good, with a low survival rate. The purpose of this study is to examine the factors that underpin the success of student startups. First, through a review of the literature, this study compared the success factors of student startups with those of venture startups, which means the general startup sector, as well as youth startups, also a focus of startup policy targeting youngsters outside universities or colleges. Second, we analyzed case studies of startup companies connected University H. The literature review showed that the main target of student startups is the employment of university students. There is a lack of studies on success factors; existing studies only emphasize the entrepreneurship of students. The results of case studies showed several factors of success similar to those of general venture startups: founders, business model and resources including team, and mentoring.

• 한국멀티미디어학회논문지
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• 제14권1호
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• pp.85-93
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• 2011

기존의 어휘 인식에서는 일반적인 벡터 값을 데이터베이스를 이용하여 구하므로 탐색 중에 형성되는 음소를 처리하지 못하는 문제점을 제공하며, 음소 데이터에 대한 모델을 구성할 수 없는 단점으로 인하여 가우시안 모텔의 정확성을 확보하지 못하게 된다. 따라서 본 논문에서는 음소가 갖는 특징을 기반으로 바타챠랴 거리 측정법을 이용하여 정확한 음소로 인식할 수 있도록 유도하였으며 유사 음소 인식과 오인식 오류를 최소화하여 인식률을 향상시켰다. 연속 확률 분포의 공유로부터 가우시안 모델 최적화를 실험한 결과 향상된 신뢰도로 인해 높은 인식 성능을 확인하였으며, 본 논문에서 제안한 바타챠랴 거리 측정법을 이용하여 실험한 결과 기존의 방법들에 비하여 평균 1.9%의 성능 향상을 나타내었으며 신뢰성을 바탕으로 인식율에서 평균 2.9%의 성능 향상을 나타내었다.

• 한국환경과학회지
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• 제4권5호
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• pp.403-411
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• 1995

The atmospheric responses to a Sea Surface Temperature Anomaly(SSTA) over the equatorial eastern Pacific Ocean have been investigated using the horizontally fine resolution model based on OSU 2-layer Atmospheric General Circulation Model(AGCM). The SSTAS daring the peak phase of 1982-83 El Nino have been applied to the model as the boundary conditions of the experiment. The model simulates the eastward movement of the rising branch of the Walker circulation. That is, the major features associated with the El Nino such as the increase of the precipitation rate over the center of the Pacific and decrease over the Indonesia, and the 500hPa geopotential height anomaly in the middle latitude are properly describes in the fine resolution model experiment. The model results indicate that this horizontally fine resolution UM can successfully simulate the ENSO anomalies and be more effectivelly used for the study of the climate and the climate changes.

• Journal of Preventive Medicine and Public Health
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• 제23권1호
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• pp.11-21
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• 1990

This study refers to the problem of long-term inpatient flow in a general hospital. In this study, a queueing simulation model was developed for the two departments in the hospital with a homogeneous case mix and relatively many long-term inpatients in order to increase the turnover rate and hospital charges. Before the simulation n, the model was verified by the Kolmogorov-Smirnov test. The following results were generated by three alternative models of the special bed policies. 1. Alternative I : When long term inpatients were admitted to the wards belonging to departments A and B without transfer to other departments and special beds, the average turn-over rate decreased by 2-4% and the average hospital charges decreased by 70 million won. 2. Alternative II : When long-term inpatients were transferred to department C but the transfer of wards was determined by department C in order of clinical need, the average turnover rate increased by 4-13% but the average hospital charges decreased by 30 million won. This result was not greatly different from the present state. 3. Alternative III : When long-term inpatients were transferred to the special wards and department C simultaneously, the increase in the average turnover rate and hospital charges was equivalent to the increase of two beds in the special wards. When the special wards were allocated 16 beds, the average turnover rate of departments A and B increased by about 55% and 20% respectively. Also, the hospital charges increased by about 0.44 billion won. As a result, transfer to department C and the use of 16 beds in the special wards for long-term inpatients of departments A and B is expected to maximize the hospital revenue. However, as the above special bed policy can not increase the turnover rate above 60%, there is a need for a more comprehensive policy to further increase the rate. The development of an elaborate model should include the number of long-term inpatients in all clinical departments, the special wards system or an increase of hospital beds to handle admission needs, and the resources of the hospital by department. When the alternatives are evaluated, a cost-benefit analysis in addition to the turnover rate and the hospital charges should be considered.

• 수산해양교육연구
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• 제10권1호
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• pp.1-14
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• 1998

Transportation provides an infrastructure vital to economic growth, and it is also an integral part of production. As a port is regarded as the interface between the maritime transport and domestic transport sectors, it certainly play a key role in any economic development. Ship's delay caused by port congestion has recently has recently attracted attended with the analysis of overall operation in port. In order to analyse complicated port operation which contains large number of variable factors, queueing theory is needed to be adopted, which is applicable to a large scale transportation system in chiding ship's delay in Inchon port in relation to ship's delay problem. The overall findings are as follows ; 1. The stucture of queueing model in this port can be represented as a complex of multi-channel single-phase 2. Ship's arrival and service pattern were Poisson Input Erlangian Service. 3. The suitable formula to calculate the mean delay in this port, namely, $W_q={\frac{{\rho}}{{\lambda}(1-{\rho})}}{\frac{e{\small{N}}({\rho}{\cdot}N)}{D_{N-1}({\rho}{\cdot}N)}}$ Where, ${\lambda}$ : mean arrival rate ${\mu}$ : mean servicing rate N : number of servicing channel ${\rho}$ : utilization rate (l/Nm) $e{\small{N}}$ : the Poisson function $D_{(n-1)}$ : a function of the cumulative Poisson function 4. The utility rate is 95.0 percents in general piers, 75.39 percents in container piers, and watiting time 28.43 hours in general piers, 13.67 hours in container piers, and the length of queue is 6.17 ships in general piers, 0.93 ships in container piers, and the ship turnaround time is 107.03 hours in general piers, 51.93 hours in container piers.