• JSTS:Journal of Semiconductor Technology and Science
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• 제1권3호
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• pp.182-188
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• 2001

A solenoid-type MEMS inductor with a quality factor over 10 at 2 GHz has been developed using an electroplating technique. The integrated spiral inductor has a low Q factor due to substrate loss and skin effects. It also occupies a large area compared to the solenoid-type inductor. The direction of flux of the solenoid-type inductor is parallel to the substrate, which can lower the substrate loss and other interference with integrated passive components. To estimate the characteristics of the proposed inductor over a high frequency range, the 3D FEM (Finite Element Method) simulation is used by using the HFSS at the Ansoft corporation. The electroplated solenoid-type inductor is fabricated on a glass substrate step by step by using photolithography and copper electroplating. The fabrication process to improve the quality factor of the inductor is also developed. The achieved inductance varies within a range from 0.5 nH to 2.8 nH, and the maximum Q factor is over 10.

• 재무관리연구
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• 제20권1호
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• pp.213-231
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• 2003

본 연구에서는 우리나라 주식시장에서 연속시간모형의 실증적 탐구와 확장을 위하여 정교하고 포괄적인 방법론을 도입하고자 하였다. 즉 확률변동성(Stochastic Volatility) 모형을 이용하여 우리나라 주식수익률 과정을 연속시간모형으로 설정하고 이런 정교한 연속모형의 추정을 위하여 효율적 적률법(EMM)을 도입하였다. 본 연구의 분석기간은 1995년 1월 3일부터 2002년 12월 30일까지이며 분석대상은 일별 KOSPI 지수 2150 관측치 이다. 연구모형 분석결과 우리나라 주가지수 수익률의 비정규성, leptokurtic한 분포 및 확률변동성 등이 추정되었으며 특히 EMM 모형의 추정결과 우리나라 주식시장의 주가지수 수익률과정은 단일요인(one factor) 확률변동성 모형보다는 2 요인(two factor) 확률변동성 모형을 도입하는 것이 더 바람직한 것으로 판명되었고 또한 확률변동성 모형을 설정할 때에는 우리나라의 개별 주식수익률뿐만 아니라 주가지수 수익률 등에도 존재되는 것으로 알려진 점프 특성 고려의 필요성이 증대되었다. 외환위기 이후 주식시장의 변동성 급등락 현상이 갈수록 심화되어 금융자산 위험관리의 필요가 절실히 요구되는 요즘시기에 기초자산의 수익률과정 및 확률변동성 특성을 심층적으로 분석하는 본 연구를 통하여 각종 금융기관 및 투자자들의 투자기회비용과 시행착오를 줄이는데 큰 도움을 줄 수 있을 것으로 기대된다.

• 한국환경과학회지
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• 제22권2호
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• pp.225-234
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• 2013

The relationship between debris flow and topographical factors is essential for the reliable estimation of soil loss. The objective of this paper is to estimate stability index and soil loss for assessing landsliding risk caused by debris flow. SIMAP and RUSLE are used to estimate stability index and soil loss, respectively. The landsliding risk area estimated by using SIMAP is found to be different from the large land area estimated by RUSLE. It is found that the spatial distribution of soil cover significantly influences landsliding risk area. Results also indicate that stability index and soil loss, estimated by soil cover factor, improve the assessment of landsliding risk.

• 한국토양비료학회지
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• 제46권5호
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• pp.359-364
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• 2013

This study was conducted to develop a model to estimate crop leaf surface temperature. The results were as following; A definition for the daily time based on elapsed time from the midnight (00:00) as "E&E time" with the unit of Kmin. was suggested. The model to estimate the scaled temperature ($T^*e$) of crop leaf surface temperature by scale factor ($T^*$) according to the "E&E time : Kmin."(X) was developed as eq. (1) $T^*e=0.5{\cdot}sin(X+780)+0.5$ (2) $T^*=(Tx-Tn)/(Tm-Tn)$, Tx : Daily leaf temperature, Tm : Daily maximum leaf temperature, Tn : Daily minimum leaf temperature. Relative sensitivity of the measured temperature compared to the estimated temperature of red pepper, soybean and persimmon was 1.078, 1.033 and 0.973, respectively.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1276-1282
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• 2013

This paper proposes a stochastic modeling of plug-in electric vehicles (PEVs) distribution in power systems, and analyzes the corresponding clustering characteristic. It is essential for power utilities to estimate the PEV charging demand as the penetration level of PEV is expected to increase rapidly in the near future. Although the distribution of PEVs in power systems is the primary factor for estimating the PEV charging demand, the data currently available are statistics related to fuel-driven vehicles and to existing electric demands in power systems. In this paper, we calculate the number of households using electricity at individual ending buses of a power system based on the electric demands. Then, we estimate the number of PEVs per household using the probability density function of PEVs derived from the given statistics about fuel-driven vehicles. Finally, we present the clustering characteristic of the PEV distribution via case studies employing the test systems.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 2008년도 연합학회학술대회
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• pp.487-491
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• 2008

After 1990, Korean information technology industry was developed enormously. To estimate these situation, there were many studies such as based on resource based view, transaction cost theory, and so on. These studies were focused on the efforts of company itself and the main body of development were the company not environmental factors. But in developing countries such as Korea, environment which is government policies, other companies, etc. is important factor. So present study estimate the environmental factors for evolution of Korean IT industry with population ecology concept.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권3호
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• pp.181-187
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• 2017

Purpose: The purpose of this study is to estimate the lifetime of commercial passenger vehicles shock absorber using degradation test and data. Method: The degradation factor of shock absorber was determined to be a damping force using FMEA. Degradation test was performed on damping force under real world usage condition and analysed the degradation data. Results: To estimate the lifetime of shock absorber, a degradation model was developed and a numerical example was provided. Conclusion: Evaluation of the lifetime of commercial and military vehicles shock absorber will be possible by using the proposed degradation analysis method.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권4호
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• pp.708-719
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• 2015

The two most important tasks of icebreakers are first to secure a sailing route by breaking the thick sea ice and second to sail efficiently herself for purposes of exploration and transportation in the polar seas. The resistance of icebreakers is a priority factor at the preliminary design stage; not only must their sailing efficiency be satisfied, but the design of the propulsion system will be directly affected. Therefore, the performance of icebreakers must be accurately calculated and evaluated through the use of model tests in an ice tank before construction starts. In this paper, a new procedure is developed, based on model tests, to estimate a ship's ice breaking resistance during continuous ice-breaking in ice. Some of the factors associated with crushing failures are systematically considered in order to correctly estimate her ice-breaking resistance. This study is intended to contribute to the improvement of the techniques for ice resistance prediction with ice breaking ships.

• 한국정보처리학회논문지
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• 제6권3호
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• pp.766-772
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• 1999

With the increase of portable system and high-density IC, power consumption of VLSI circuits is very important factor in design process. Power estimation is required in order to estimate the power consumption. A simple and correct solution of power estimation is to use circuit simulation. But it is very time consuming and inefficient way. Probabilistic method has been proposed to overcome this problem. Transition density using probability was an efficient method to estimate power consumption using BDD and Boolean difference. But it is difficult to build the BDD and compute complex Boolean difference. In this paper, we proposed Propowest. Propowest is building a digraph of circuit, and easy and fast in computing transition density by using modified COP algorithm. Propowest provides an efficient way for power estimation.

• 한국군사과학기술학회지
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• 제15권1호
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• pp.101-110
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• 2012

The side jet effects between jet flow and free-stream on a missile body were investigated by experimentally and numerically for modeling aerodynamic coefficients in pitch plane. K-factors for normal force and pitching moment were introduced to estimate the side jet effects. The main parameters of the jet interaction phenomena were angle of attack, jet pressure ratio, Mach number and jet bank angle. The K-factors for normal force coefficient and pitching moment coefficients in pitch plane were analysed.