• Journal of Computing Science and Engineering
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• 제2권3호
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• pp.274-300
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• 2008

Software testing cost can be reduced if the process of testing is automated. However, the test data generation task is still performed mostly by hand although numerous theoretical works have been proposed to automate the process of generating test data and even commercial test data generators appeared on the market. Despite prolific research reports, few attempts have been made to evaluate and characterize those techniques. Therefore, a lot of works have been proposed to automate the process of generating test data. However, there is no overall evaluation and comparison of these techniques. Evaluation and comparison of existing techniques are useful for choosing appropriate approaches for particular applications, and also provide insights into the strengths and weaknesses of current methods. This paper conducts experiments on four representative test data generation techniques and discusses the experimental results. The results of the experiments show that the genetic algorithm (GA)-based test data generation performs the best. However, there are still some weaknesses in the GA-based method. Therefore, we modify the standard GA-based method to cope with these weaknesses. The experiments are carried out to compare the standard GA-based method and two modified versions of the GA-based method.

• 한국해양학회지
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• 제15권1호
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• pp.1-7
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• 1980

The results of measurements of shear current induced in water by wind in wind wave tunnel are presented briefly. The shear current distributions are found to fit reasonably well an exponentiall form. This form was used to estimate surface velocity and boundary layer thickness used in stability analysis. An analysis of hydrodynamic stability of the shear current was carried out, using a broken line as an approximate profile, to see the stability as a possible mechanism of wind wave generation. Comparison between experimental results and theoretical ones shows that there exists a large discrepancy particularly in phase velocity and hydrodynamic instability of the shear current seems not to be the basic mechanism of wind wave generation.

• 대한산업공학회지
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• 제1권1호
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• pp.87-92
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• 1975

Three approximation methods for generating outcomes on Poisson random variables are discussed. A comparison is made to determine which method requires the least computer execution time and to determine which is the most robust approximation. Results of the comparison study suggest the method to choose for the generating procedure depends on the mean value of Poisson random variable which is being generated.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권2호
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• pp.524-539
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• 2014

To investigate schemes of secret key generation from Ultra-wideband (UWB) channel, we study a statistical characterization of UWB outdoor channel for a campus playground scenario based on extensive measurements. Moreover, an efficient secret key generation mechanism exploiting multipath relative delay is developed, and verification of this algorithm is conducted in UWB Line-of-sight (LOS) outdoor channels. For the first time, we compare key-mismatch probability of UWB indoor and outdoor environments. Simulation results demonstrate that the number of multipath proportionally affects key generation rate and key-mismatch probability. In comparison to the conventional method using received signal strength (RSS) as a common random source, our mechanism achieves better performance in terms of common secret bit generation. Simultaneously, security analysis indicates that the proposed scheme can still guarantee security even in the sparse outdoor physical environment free of many reflectors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.106-109
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• 1992

This paper Introduces the concept of the generation cost of generating utilities and its calculation methods. Also, the economic evaluation method using generation cost which is called as a screening curve method will be presented along with the benefits and disadvantages of this concept. Next, the least-cost electric utility planning techniques which is used very widely in many countries will be Introduced In comparison with screening curve method. In this aspects, the optimal dynamic mix can be determined as a result. By comparing these two concepts, we will get the concrete concept why the economic evaluation method using generation cost can not be used for the future generation expansion planning.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.707-714
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• 2022

Hydrogen production using solid oxide electrolysis cells (SOEC) is a promising technology because of its efficiency, cleanness, and scalability. Especially, high-power SOEC system has received a lot of attention from researchers. This study compared and analyzed the low-power and high-power SOEC system in term of economic. By using revenue requirement method, levelized cost of hydrogen (LCOH) was calculated for comparison. In addition, the sensitivity analysis was performed to determine the dependence of hydrogen cost on input variables. The results indicated that high-power SOEC system is superior to a low-power SOEC system. In the capital cost, the stack cost is dominant in both systems, but the electricity cost is the most contributed factor to the hydrogen cost. If the high-power SOEC system combines with a nuclear power plant, the hydrogen cost can reach 3.65 $/kg when the electricity cost is 3.28 ¢/kWh and the stack cost is assumed to be 574 $/kW.

• 정보과학회 논문지
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• 제42권11호
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• pp.1386-1396
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• 2015

안드로이드(Android) 어플리케이션(앱)의 신뢰성과 사용성 검증을 위해, 앱의 기능 검사와 크래쉬(Crash) 탐지 등을 위한 다양한 GUI 테스팅(Graphical User Interface Testing) 기법이 널리 사용되고 있다. 그 중 모델 기반(Model-based) GUI 테스팅 기법은 GUI 모델을 이용해 테스트 케이스를 생성하기 때문에, 기법의 유효성(Effectiveness)은 기반 모델의 정확도에 의존적이다. 따라서 모델 기반 기법의 유효성 향상을 위해서는 테스트 대상 앱의 행위를 충분히 반영할 수 있는 모델 생성 기법이 필요하며, 이를 위해 본 연구에서는 GUI 상태를 정밀하게 구분하는 계층적 화면 비교 기법을 통해 테스팅의 유효성과 효율성을 향상시키고자 한다. 또한, 기존 연구 기법과의 비교 실험을 통해 제안 기법이 유효한 모델의 효율적 생성을 가능하게 함을 확인함으로써, 모델 기반 안드로이드 GUI 테스팅의 성능 향상 가능성을 제시한다.

• 한국멀티미디어학회논문지
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• 제8권9호
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• pp.1248-1257
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• 2005

본 논문은 통신보조시스템을 위한 문장생성의 구현과 설계에 관한 것이다. 통신보조시스템은 언어장애인을 위한 보조 시스템으로서 시간과 키의 수를 줄여 문장을 생성하는데 그 목적이 있다. 본 논문에서는 기존의 문장생성의 장단점을 보완하여 문장생성을 하였다. 문장생성을 위하여 동사와 조사에 따라 명사가 한정되는 한글 구조를 이용하였다. 본 논문의 특징은 도메인 개념을 이용하여 명사와 동사를 연결하였다. 문장생성을 위해 한글의 특성으로 구축한 어휘정보를 이용하였다. 또한 현재 문장생성에 관한 여러 방법을 비교하였다. 문장생성은 문장특징 추출에 의한 어휘정보에 바탕을 둔다.

• 물과 미래
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• 제13권1호
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• pp.49-56
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• 1980

The thesis of this analytical study includes 1) the generation of annual and monthly discharge regarding single hydrological variable at single site, 2)comparsion with the historical records and the generation, and 3) changing the monthly generatied discharge into annual. The conclusion of this will be used for the future plan for water resources development. Annual discharges at waegwan are characterized by log-normal distirbution and persistence-absent. Also, the random number generator causes the errors in the generation of annual discharge. The serial correlation coefficients of the generated annual discharge have less value than that of historical records, while the correlation coefficient and slope in January have(+) value and opposite to historical record. To change the monthly generated discharge into annual is not proper.

• 전기학회논문지
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• 제58권12호
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• pp.2349-2353
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• 2009

Due to high oil price and global warming of the earth, investments for renewable energy have been increased a lot continuously. Specially, wind power has been received a great attention in the world. In order to construct a new wind farm, forecasting of wind power generation is essential for a feasibility test. This paper investigates wind velocity measurement data of Gosan weather station which located in Hankyung of Jeju island. This paper presents results of estimation of wind power generation using digital weather forecast provided from Korea meteorological administration, and the accuracy of the wind power forecasting by comparison between forecasted data and actual wind power data.