• 한국측량학회지
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• 제20권2호
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• pp.215-222
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• 2002

As the GPS signals propagate from the GPS satellites to the receivers on the ground, they are delayed by the atmosphere. The tropospheric delay consists of two components. The hydrostatic (or "dry") component that is dependent on the dry air gasses in the atmosphere and accounts for approximately 90% of the delay. And the "wet" component that depends on the moisture content of the atmosphere and accounts for the remaining effect of the delay. The Zenith Hydrostatic Delay (ZHD) can be calculated from the local surface pressure. The Total Zenith Delay (TZD) will be estimated and the wet component extracted later. Integrated water Vapor (IWV) gives the total amount of water vapor that a signal from the zenith direction would encounter. Precipitable Water Vapor (PWV) is the IWV scaled by the density of water. The quality of this PWV has been verified by comparison with radiosonde data(at Osan). We processed data for JULY 2 and JULY 14, 1999 from four stations(Cheju, Kwangju, Suwon, Daegu). We found the coincidence between PWV of the estimations using GPS and PWV of pressing the radiosonde data. The average of the difference between PWV using GPS and PWV using radiosonde was 3.77 mm(Std. ＝ $\pm$0.013 mm) and 2.70 mm(Std. = $\pm$0.0011 mm) at Suwon & Kwangju.

• KIEAE Journal
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• 제9권1호
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• pp.31-38
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• 2009

The purpose of this study is to present direction in outdoors space planning and design after direction through user characteristic analysis through spectacle component establishment of culture art center outdoors space through on-the-site analysis and literature investigation to culture art center of Seoul city and capital region 17 places in this research. The data was collected from classification and bisection kind, subdivision kind, and great classification composed to 17 items. User satisfaction side and Variable that is looked below satisfaction than average appeared to bench, pergola, sculpture facilities, pavement facilities, border facilities. And these facilities were analyzed dissatisfaction. When see satisfaction model, when make up culture art center or similar facilities in local government hereafter because parking facilities and rest area cause big effect in satisfaction, is judged that is item to consider most preferentially. In most case, parking lot security from outdoors space, resting place security, security of field performance facilities etc. taking a serious view because tendency that users see performance or use most vehicles except neighborhood walking area for a rest, a walk etc.. is trend. But, is judged that physical side so that can feel satisfaction as space security of quantitative side is important but users utilize substantially and side that is the program are more important in hereafter.

• 대한전기학회논문지:전력기술부문A
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• 제48권5호
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• pp.494-501
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• 1999

In this research, ANN modeling method of SMES unit is developed for stability analysis, and the optimal site is selected to maximize stabilization effect of SMES unit. The ANN is trained by learning data which is obtained through the application of complex test function into the traditional mathematical mode. In order to verify the validity of proposed modeling method, fault data of sample power system is applied to both the traditional and the ANN models. When the response of traditional and proposed models are compared, the average error for the active and reactive power are 2.51[%], and 0.24[%], respectively. From the comparison, the relevance of proposed method is validated. For the transient stability analysis, an application method of the proposed model is presented, and the transient stability performance index, which describes system stabilization effect of SMES at disturbance, is also suggested, and optimal site selection method of SMES is presented. In the viewpoint of the voltage stability, system stabilization criterion of local bus is presented from P­V curve, and then optimal site which can maximize the voltage stabilization of the whole power system, is decided from the proposed voltage stability performance index.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2008년도 춘계학술발표대회 논문집
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• pp.280-284
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• 2008

This study is a research for revitalized characteristics of compounded community center which is a complex aid facility with a key position of regional culture and welfare. Recent complex conditions of community center and public facility is studied on this research. The methods are searches in the Internet, telephone interviews, and documents of present local conditions. The results are as follow : The community center in Seoul City support 2 million people per a center in average and self-supporting financial rate came out low. The community center formed physical shape in one building with community facilities. A district complex community center type, which is a village office united to public facilities, expected to be increased. The community center compound 1 or 2 facilities, divided 15 types. Most of community center is complex type of community center with village office and the other types are complex type of community center with a hall for the aged, nursery, and library. Accordingly, the community center keeps up the complex type of community center with village office type as a physical shape in one building and the district complex community center type complexes with hall for the aged, nursery and library.

• 에너지공학
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• 제23권2호
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• pp.21-27
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• 2014

수직평판의 거칠기에 따른 자연대류 열전달의 변화를 실험적으로 측정하였다. 열전달 실험을 대신하여 유사성에 기초한 물질전달로 모사하여 실험을 수행하였다. 또한 국부적인 열전달률을 알기위해 Piecewise electrode를 채택하였다. Pr수는 2,014 그리고 높이(L)는 0.154m로 고정하고 매끈한 수직평판에 대해 실험을 수행한 결과 Le Fevre의 수직평판 상관식과 거의 일치하였다. 거칠기 정도를 $0.5R_z{\mu}m{\sim}14.1R_z{\mu}m$로 변화시켰을 때 $Nu_L$수는 거칠기 정도가 커지면서 증가하는 경향을 나타내었다. 실험결과는 간단한 상관식으로 정리하였다.

• 자원환경지질
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• 제28권5호
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• pp.527-533
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• 1995

A disadvantage of Fourier analysis is that frequency information can only be extracted for the complete duration of a signal f(t). Since the Fourier transform integral extends over all time, from $-{\infty}$ to $+{\infty}$), the information it provides arises from an average over the whole length of the signal. If there is a local oscillation representing a particular feature, this will contribute to the calculated Fourier transform $F({\omega})$, but its location on the time axis will be lost There is no way of knowing whether the value of $F({\omega})$ at a particular ${\omega}$ derives from frequencies present throughout the life of f(t) or during just one or a few selected periods. This disadvantage is overcome in wavelet analysis which provides an alternative way of breaking a signal down into its constituent parts. The main advantage of the wavelet transform over the conventional Fourier transform is that it can not only provide the combined temporal and spectral features of the signal, but can also localize the target information in the time-frequency domain simultaneously. The wavelet transform distinguishes itself from Short Time Fourier Transform for time-frequency analysis in that it has a zoom-in and zoom-out capability.

• 한국정보통신학회논문지
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• 제19권7호
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• pp.1680-1686
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• 2015

에지 검출은 대부분의 영상 처리 응용에서 필수적인 전처리 과정으로서 여러 분야에서 널리 사용되고 있으며, 기존의 에지 검출 방법에는 Sobel, Roberts, Laplacian, LoG(Laplacian of Gaussian) 등이 있다. 기존의 에지 검출 방법들은 저조도 환경에서 화소의 휘도 변화가 적기 때문에 에지 검출 특성이 미흡하게 나타난다. 따라서 본 연구에서는 이러한 문제점을 해결하기 위해, 전처리 과정에서 휘도 변환 함수를 사용한 알고리즘과 국부 마스크의 평균 및 표준편 차에 따른 가중치를 적용하여 에지를 검출하는 알고리즘을 제안하였다. 그리고 제안한 알고리즘의 성능을 평가하기 위해, 기존의 Sobel, Roberts, Prewitt, Laplacian, LoG 에지 검출 방법들과 비교하였다.

• Nuclear Engineering and Technology
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• 제43권6호
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• pp.531-546
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• 2011

The backward differentiation formula (BDF) method is applied to a three-dimensional reactor kinetics calculation for efficient yet accurate transient analysis with adaptive time step control. The coarse mesh finite difference (CMFD) formulation is used for an efficient implementation of the BDF method that does not require excessive memory to store old information from previous time steps. An iterative scheme to update the nodal coupling coefficients through higher order local nodal solutions is established in order to make it possible to store only node average fluxes of the previous five time points. An adaptive time step control method is derived using two order solutions, the fifth and the fourth order BDF solutions, which provide an estimate of the solution error at the current time point. The performance of the BDF- and CMFD-based spatial kinetics calculation and the adaptive time step control scheme is examined with the NEACRP control rod ejection and rod withdrawal benchmark problems. The accuracy is first assessed by comparing the BDF-based results with those of the Crank-Nicholson method with an exponential transform. The effectiveness of the adaptive time step control is then assessed in terms of the possible computing time reduction in producing sufficiently accurate solutions that meet the desired solution fidelity.

• 대한기계학회논문집
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• 제13권5호
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• pp.979-990
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• 1989

본 연구에서는 종횡비가 1보다 크고 내부 벽면에 일정한 열유속을 가지고 외부벽은 등온으로 유지되며 나머지 벽은 단열된 수직환형 원통형에 대한 연구를 바탕으로 같은 경계조건으로 종횡비를 1이하로 감소할 때에 Darcy의 법칙을 기초로 유한차분법을 사용, 수치적으로 해석하여 다세포 유동의 존재 여부와 온도 분포 및 열전달율을 계산하였다.

• 대한기계학회논문집A
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• 제20권8호
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• pp.2436-2448
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• 1996

This paper presents the development of three types of network performance manager for IEEE 802.4 token bus networks that are a part of Manufacturing Automation Protocol(MAP). The performance managers attempt to keep the average data latency below a certain level specified for each priority class. All of the three performance managers are based on a set of fuzzy rules incorporating the knowledge on the relationship between data latency and parameters of the priority mechanism. These Fuzzy Network Performance Managers(FNPMs) have been evaluated via discrete event simulation to demonstrate their efficacy.