• Water Engineering Research
• /
• 제5권2호
• /
• pp.101-109
• /
• 2004

Aggregating information by combining forecasts from two or more forecasting methods is an alternative to using forecasts from just a single method to improve forecast accuracy. This paper describes the development and use of a monthly inflow forecast model based on an optimal linear combination (OLC) of forecasts derived from naive, persistence, and Ensemble Streamflow Prediction (ESP) forecasts. Using the cross-validation technique, the OLC model made 1-month ahead probabilistic forecasts for the Chungju multi-purpose dam inflows for 15 years. For most of the verification months, the skill associated with the OLC forecast was superior to those drawn from the individual forecast techniques. Therefore this study demonstrates that OLC can improve the accuracy of the ESP forecast, especially during the dry season. This study also examined the value of the OLC forecasts in reservoir operations. Stochastic Dynamic Programming (SDP) derived the optimal operating policy for the Chungju multi-purpose dam operation and the derived policy was simulated using the 15-year observed inflows. The simulation results showed the SDP model that updated its probability from the new OLC forecast provided more efficient operation decisions than the conventional SDP model.

• 한국수학교육학회지시리즈A:수학교육
• /
• 제44권2호
• /
• pp.265-280
• /
• 2005

According to the characteristics of elementary school students in favor of playing games, and to their high energy levels and physical growth states, it is fair to say that students can learn mathematics through 'game playing activities.' These activities are considered to intrigue their interest in class and make them feel less stress from the burden of studying mathematics. Mr. Skemp, who had conducted research on 'game activity' with experimental studies relating to elementary mathematics, recommends that math teachers try to give as many activity-oriented classes as possible to students. The method of 'game activity' by Skemp's operation deals with the whole range of mathematical themes. It is believed by other math teachers that this is not a way to substitute free time or just to have fun in class, but an intentionally well-organized way of learning an entire mathematical course during elementary school. In this research, 5th and 6th grade students needing extra classes after school had been exposed to 'ame activity' by Skemp's operation. As a result, we can figure out its influence on their understanding of arithmetic ability, and on the cognitive definition territory in their minds.

• 한국통신학회논문지
• /
• 제15권8호
• /
• pp.648-658
• /
• 1990

음성 인식에 있어서 계산 속도를 보다 빠르게 하기 위한 여러 방법중에 systolic array를 이용하여 multiple processign하는 방법이 있다. 이러한 systolic array의 각 연산은 pipeline 방식으로 수행되며, 이 연산은 Processing Element(PE)로 multiprocessing되어 계산 효율을 증대시키게 된다. 이 DTW용 PE cell은 크게 세가지의 블록으로 대별된다. 즉 MIN block, ADD block 그리고 ABS block인데, 본 연구에서는 이들 세가지 블록중 "ADD"와 "ABS" 대한 회로설계및 검증을 행하였으며, 3$\mu$m CMOS N-well 설계 규칙에 따라 두 블록에 대한 각각의 레이아웃과 전체 레이아웃을 설계한 후 설계 규칙 검사(DRC)를 마쳤다. 설계 규칙 검사(DRC)를 마쳤다.

• 한국경영과학회지
• /
• 제39권2호
• /
• pp.37-48
• /
• 2014

Fighter squadron flight scheduling is the integrated air operation plan that is an important role for improving pilot's flight skill and maintaining combat readiness by efficient using available all air resources including pilot, aircrafts, air-weapons, fuel and supporting facilities etc. Korea airforce, however, has a limit as to an effective flight operation due to manual flight scheduling with scheduler's own experience and intuition. Therefore, in our study, we propose the optimization model of flight scheduling based on mixed integer programming. This model includes several constraints of realistic and essential quantified data related with flight schedule and can assign appropriate pilots optimally which are distinctive three type's solutions : flight, alert and duty crew schedules. Proposed solution method can be improved pilot's capability and allocated further air resources systematically and efficiently. In addition, it can be reduced a workload of flight scheduler and minimized obstructed factors of flight safety. Finally, we demonstrate the experiment's results for the check of efficiency and validity of this model.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 Asia Navigation Conference
• /
• pp.63-70
• /
• 2006

Now AIS (Automatic Identification System) has been under full operation for ocean-going vessels, and it is expected not only to identify target ships but also to take collision avoidance using AIS information with Radar and ARFA information in restricted waters. AIS information is very useful not only for target identifications but also for taking collision avoidance, but OOW (Officer OF Watch-keeping) should take care of systematic observation of AIS because of miss-operation or malfunction of AIS. In this paper, we propose the application of Onboard Ship Handling Simulator with visual system displayed 3D scene added AIS performance such as blind areas of Island, microwave propagation, ok. and maneuvering simulation using TK models, applied real time AIS information and research the effectiveness of this system for ship handling in restricted waters, and discus the principal issues through the on board experiments. Conclusion will be expected that; 1) systematic observation of ASS information using visual scene simulator with AIS information will be effectively done, 2) observation compared with Radar and ARPA information will be also useful to make a systematic observation, 3) using the recording and replay function of simulation will be useful not only for systematic observation but also to measure and to encourage officers' skill.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2005년도 춘계학술대회
• /
• pp.516-519
• /
• 2005

The pilot tidal current power plant is to be constructed at the Uldolmok between Chindo and Haenam, during next year. and extensive coastal engineering research works have been carried out. In this paper we describes some observation results of the tide and tidal current. as well as modeling work in order to investigate the tide and tidal current regime change in relation to the tidal current power plant (TCPP) construction. The special modeling skill in order to consider the turbine operation in the TCPP is developed and applied to the estimation for the flow regime change by the simple layout of the tidal current power plant.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
• /
• pp.587-590
• /
• 2005

A detailed geothermal characteristics survey with numerical simulations of the heat transfer in a site for ground source heat pump system is necessary for deploying a shallow geothermal utilization system. Density, specific heat, thermal diffusivity, and thermal conductivity are measured on 91 core samples from a 300 m deep borehole in KIGAM(Korea Institute of Geoscience and Mineral Resources). The heat flow is estimated from the thermal gradient and average thermal conductivity and the correlation between fracture system and hydraulic conductivity is analyzed. From the obtained ground information of the study site the performance of the ground heat pump system can be analyzed with some detailed numerical simulations for seasonal heat pump operation skill and optimal system design techniques.

• International Journal of Precision Engineering and Manufacturing
• /
• 제3권4호
• /
• pp.43-53
• /
• 2002

Polishing a die that has free-form surfaces is a time-consuming and tedious job, and requires a considerable amount of high-precision skill. In order to reduce the polishing time and cope with the shortage of skilled workers, a user-friendly automatic polishing system was developed. The polishing system is composed of two subsystems, a three-axis machining center and a two-axis polishing robot. The system has five degrees of freedom and is able to keep the polishing tool in a position normal to the die surface during operation. A sliding mode control algorithm with velocity compensation was proposed to reduce tracking errors. Trajectory tracking experiments showed that the tracking error can be reduced prominently by the proposed sliding mode control compared to a PD (proportional derivative) control. To evaluate the polishing performance of the polishing system and to and the optimal polishing conditions, the polishing experiments were conducted.

• 신재생에너지
• /
• 제1권2호
• /
• pp.73-78
• /
• 2005

The pilot tidal current power plant is to be constructed at the Uldolmok between Chindo and Haenam, during next year, and extensive coastal engineering research works have been carried out. In this paper we describes some observation results of the tide and tidal current, as well as modeling work in order to investigate the tide and tidal current regime change In relation to the tidal current power plant [TCPP] construction. The special modeling skill in order to consider the turbine operation in the TCPP is developed and applied to the estimation for the flow regime change by the simple layout of the tidal current power plant.

• 기술사
• /
• 제22권3호
• /
• pp.5-13
• /
• 1989

A major problem of stopwatch time study is how to do for the accurate and consistent performance rating, which is one of the critical variables to determine the accuracy of work measurement and should be still dependent upon time observer's judgement. Therefore the time observer's ability for the performance rating is very important, and must be improved by correct training method and procedure. This paper developed a new benchmark and benchmark-observation method for the effective performance rating training of assembling and machining operations. The trainees' ability in the accuracy and consistency of the performance rating ,improved significantly after being trained by subject method. The percentage improvement in rating accuracy and consistency values was 34.7% and 49% respectively. In addition, benchmark-practice method for the performance rating training is not significant, so it is proofed that the skill of a certain operation is not important for the improvement of the rating ability.