• 전자공학회논문지S
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• 제35S권2호
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• pp.79-88
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• 1998

We developed a method for the solid angle estimation of acetabular coverage of the femoral head in 3D space. The superior half of the femoral head is modeled as part of a sphere. And the tangent lines connecting from a set of points of the acetabular outline to the center of the fitted sphere are obtained. The lines passthrough the unit sphere whose center is the same as that of the femoral head. The interesecting points form a boundary on the unit sphere. With the points on the unit sphere, we calculate the covered area of the femoral headand estimate the solid angle. Solid angle is defined asthe suface area within the boundary on the unit sphere. In this measurements, the solid angle of normal subjects is on an average 4.3(rad) and the corresponding acetabular coverage is 68%. Unlinke the conventional methods, this solid angle estimation shows real 3D acetabular coverage.

• Journal of the Korean Data and Information Science Society
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• 제26권3호
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• pp.755-762
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• 2015

One of the main objectives of the U.S. Census Bureau is the proper estimation of median household income for small areas. These estimates have an important role in the formulation of various governmental decisions and policies. Since direct survey estimates are available annually for each state or county, it is desirable to exploit the longitudinal trend in income observations in the estimation procedure. In this study, we consider Fay-Herriot type small area models which include time-specific random effect to accommodate any unspecified time varying income pattern. Analysis is carried out in a hierarchical Bayesian framework using Markov chain Monte Carlo methodology. We have evaluated our estimates by comparing those with the corresponding census estimates of 1999 using some commonly used comparison measures. It turns out that among three types of time-specific random effects the small area model with a time series random walk component provides estimates which are superior to both direct estimates and the Census Bureau estimates.

• 대한전자공학회논문지TC
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• 제40권4호
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• pp.30-44
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• 2003

마이크로/피코셀 환경 하에서 이동체의 빈번한 위치 및 셀간 이동으로 인하여 많은 부가 트래픽이 발생한다. 이동체 위치 추정을 이용함으로서 효율적인 채널 할당과 QoS를 보장하는 핸드오프가 가능하다. 기존의 이동체 위치 추정 방안들은 단지 LOS 환경을 기반으로 하여 제시되었고 다중 경로 환경 또는 shadowing 환경에서는 성능의 감소를 가져왔다. 본 연구에서는 NLOS 환경, 그리고 수신 신호 세기 이외에 부정확한 다수의 위치 결정 파라미터를 고려함으로서 추정의 정확성을 증가시키는 새로운 위치 추정 방안들을 제시한다.

• 전기학회논문지P
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• 제60권1호
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• pp.32-36
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• 2011

In this study, authors have proposed the autonomous state estimation which has been composed with IEC61850, GPS time synchronization and objective model design concept. The proposed method is able to supervise/correct measurement and communication error from SCADA. The major advantages of the proposed autonomous state estimation are that it is possible to evaluate integrity of data measured and transferred from SCADA, to reduce human intervention and to expense national-size applications such as EMS (Energy Management System), WAMS (Wide Area Monitoring System) or WAPS (Wide Area Protection System). This study addresses the issues related to the operation of the smart grid and proposes a new automated approach to achieve this goal. Through applying the proposed system to IEEE 14-bus test electric system, we prove the possibility of the proposed idea.

• 지역연구
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• 제11권2호
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• pp.1-17
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• 1995

Regional production structres are investigated through an estimation of three-input(labor, capital and material) translog cost function. The estimation uses the pooled data in which time series data of 1970-1990 are combined with cross-sectional data corresponding to firm sizes. The empirical finding are the following: (1) the factors are Allen substitutes each otner in general except Pusan and a couple of regionss, and (2) estimates are very small in its absolute value irrespective of the regions. The low elasticity estimates of this study implies that substitytability among the three inputs are very weak in the regional manufacturing production compared to that in the national production. Seoul-Kyungki metropolitan area produces not only the smallest elasticities but relatively stable estimates without much fluctuation between the sub-regions of the area.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.332-333
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• 2008

This paper presents an estimation method of national wind resource potential using a national and GIS(Geographical Information System). The wind resource potential is classified into theoretical, geographical and technical potentials and each category narrows down the previous definition by excluding impossible area to be developed as a wind farm using GIS datasets for onshore and offshore. As a basic unit of wind energy potential at a certain area, API(Average Power Intercepted) is calculated from WPD(Wind Power Density) given by a national wind map which is established by numerical wind simulation, so that a logical and relatively accurate potential estimation is possible comparing with other methods based on a field measurement interpolation which is inevitable to avoid critical assumptions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.77-79
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• 2003

New cities and industrial complexes are being developed actively because of the government policies aiming population distribution and vitalization of construction industry. To determine the investment amount, number of power lines and substations for stable power supply to newly developed residential and industrial complexes, accurate estimation of power demand is necessary. This paper propose standards for the estimation of power demands for power company and construction company to settle the debates surrounding this issue. Through a survey and analysis of existing areas, new standards that will enable more accurate estimation of power demands in new cities complexes to be developed in the future are established by calculating the average load density, load factor, utilization factor by area, use and building size after dividing the facilities into building type and the areas into the areas planned to be developed and the areas not yet planned to be developed.

• 항공우주기술
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• 제7권1호
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• pp.216-222
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• 2008

본 연구에서는 초분광 원격탐사 기법을 이용하여 선박의 접근이 어려운 연안지역의 수심을 산정하고자 한다. 연구에 사용된 영상은 초분광 위성영상인 EO-1 Hyperion 영상이며, 대기보정 및 기하보정을 실시하였다. 보정된 영상은 MNF 변환을 사용하여 밴드를 압축하였다. 또한 각 화소의 실제적인 수심을 산정하기 위하여 대상지역의 Diffuse Attenuation Coefficient를 영상내에서 결정하였다. 그리고 Linear Spectral Unmixing 기법을 사용하여 대상 화소의 Emdmember를 결정하고, 수심을 산정하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.309-310
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• 2021

In order to respond to environmental problems and to efficiently recycle resources, it is important to evaluate the amount of construction waste generated. In particular, the estimation of the amount of waste generated in the demolition work was performed based on the basic unit of waste generated per floor area. This study proposes a method using drones as a method for evaluating the amount of demolition waste in a wide area. In the simulated application, the field measurement results and the proposed method were compared, and the effectiveness of the building volume calculation using drones was confirmed. It was confirmed that the building volume can be calculated quickly in the additional pilot application.

• 한국농공학회지
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• 제26권4호
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• pp.52-65
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• 1984

In general precise estimation of hourly of daily distribution of the long-term run-off should be very important in a design of source of irrigation. However, there have not been a satisfying method for forecasting of stationar'y long-term run-off in Korea. Solving this problem, this study introduces unit-hydrograph method frequently used in short-term run-off analysis into the long-term run-off analysis, of which model basin was selected to be Sumgin-river catchment area. In the estimation of effective rainfall, conventional method neglects the Soil moisture condition of catchment area, but in this study, the initial discharge (qb) occurred just before rising phase of the hydrograph was selected as the index of a basin soil moisture condition and then introduced as 3rd variable in the analysis of the reationship between cumulative rainfall and cumulative loss of rainfall, which built a new type of separation method of effective rainfall. In next step, in order to normalize significant potential error included in hydrological data, especially in vast catchment area, Snyder's correlation method was applied. A key to solution in this study is multiple correlation method or multiple regressional analysis, which is primarily based on the method of least squres and which is solved by the form of systems of linear equations. And for verification of the change of characteristics of unit hydrograph according to the variation of a various kind of hydrological charateristics (for example, precipitation, tree cover, soil condition, etc),seasonal unit hydrograph models of dry season(autumn, winter), semi-dry season (spring), rainy season (summer) were made respectively. The results obtained in this study were summarized as follows; 1.During the test period of 1966-1971, effective rainfall was estimated for the total 114 run-off hydrograph. From this estimation results, relative error of estimation to the ovservation value was 6%, -which is mush smaller than 12% of the error of conventional method. 2.During the test period, daily distribution of long-term run-off discharge was estimated by the unit hydrograph model. From this estimation results, relative error of estimation by the application of standard unit hydrograph model was 12%. When estimating by each seasonal unit bydrograph model, the relative error was 14% during dry season 10% during semi-dry season and 7% during rainy season, which is much smaller than 37% of conventional method. Summing up the analysis results obtained above, it is convinced that qb-index method of this study for the estimation of effective rainfall be preciser than any other method developed before. Because even recently no method has been developed for the estimation of daily distribution of long-term run-off dicharge, therefore estimation value by unit hydrograph model was only compared with that due to kaziyama method which estimates monthly run-off discharge. However this method due to this study turns out to have high accuracy. If specially mentioned from the results of this study, there is no need to use each seasonal unit hydrograph model separately except the case of semi-dry season. The author hopes to analyze the latter case in future sudies.