• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권7호
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• pp.2879-2890
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• 2020

In this paper, we study the estimation of angle, range and polarization parameters of a bistatic polarization sensitive frequency diverse array multiple-input multiple-output (PSFDA-MIMO) radar system. The application of polarization sensitive array in receiver is explored. A signal model of bistatic PSFDA-MIMO radar system is established. In order to utilize the multi-dimensional structure of array signals, the matched filtering radar data can be represented by a third-order tensor model. A joint estimation of the direction-of-departure (DOD), direction-of-arrival (DOA), range and polarization parameters based on parallel factor (PARAFAC) algorithm is proposed. The proposed algorithm does not need to search spectral peaks and singular value decomposition, and can obtain automatic pairing estimation. The method was compared with the existing methods, and the results show that the performance of the method is better. Therefore, the accuracy of the parameter estimation is further improved.

• 한국터널지하공간학회 논문집
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• 제10권4호
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• pp.421-430
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• 2008

불연속면이 발달한 암반 내에서 해저터널을 건설할 경우 절리내의 지하수 흐름이 터널거동에 커다란 영향을 미치므로 안정성 평가 시 수리-역학적 연계해석이 필요하다. 이에 본 연구에서는 불연속체의 연계해석 시 터널의 안전율을 산정하는 루틴의 검증을 위해 민감도 분석을 수행하였다. 이를 위해 암반블록과 절리의 상호작용을 해석할 수 있는 UDEC-2D 프로그램을 이용하였으며 총 324가지의 경우에 대하여 수치해석을 수행하였다. 결과적으로 불연속체 연계해석을 위해 제안된 안전율 산정 루틴이 타당한 결과를 줌을 확인하였다. 따라서, 본 연구에서 사용된 안전율 산정 방법이 불연속 암반 내에 시공되는 해저터널의 안정성 평가 시 효과적으로 사용될 수 있을 것으로 기대된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권3호
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• pp.52-64
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• 2020

The universal soil loss equation (USLE), a model for estimating the potential soil loss, has been used not only in research areas but also in establishing national policies in South Korea. Despite its wide applicability, USLE cannot adequately address the effect of seasonal variances. To overcome this limit, the ArcGIS-based Sediment Assessment Tool for Effective Erosion (ArcSATEEC) has been developed as an alternative model. Although the field-scale (< 100 ㎡) application of this model produced reliable estimation results, it is still challenging to validate accuracy of the model estimation because it only estimates potential soil losses, not the actual sediment yield. Therefore, in this study, a method for estimating actual soil loss based on the ArcSATEEC model was suggested. The model was applied to eight watersheds in South Korea to estimate sediment yields. Correction factor was introduced for each watershed, and the estimated sediment yield was compared with that of the estimated yield by LOAD ESTimator (LOADEST). Sediment yield estimation for all watersheds exhibited reliable results, and the validity of the proposed correction factor was confirmed, suggesting the correction factor needs to be considered in estimating actual soil loss.

• 한국통신학회논문지
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• 제41권9호
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• pp.1141-1145
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• 2016

일반적으로 RLS 알고리즘에서 비정재성(non-stationary) 환경에서 시간에 따라 변하는 파라메터를 좀 더 잘 추정하기 위해서 가변 망각인자를 사용한다. RLS 알고리즘에서 가변 망각인자를 사용할 때는 연산량이 많이 증가하는 단점이 수반된다. 본 논문에서는 연산량이 적은 가우스 뉴턴 가변망각인자 RLS 알고리즘을 제안한다. 본 방법은 기존 가우스 뉴턴 가변망각인자 RLS와 거의 유사한 성능을 보유하고 있을 뿐만 아니라 부가로 요구되는 연산량을 $O(N^2)$에서 O(N)으로 줄이는 효과도 준다.

• International Journal of Internet, Broadcasting and Communication
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• 제12권3호
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• pp.95-101
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• 2020

We studied the Implementation and design of inertial sensor that enables to improve performance by reduce the noise of rotor which Angle of inclination. Analyze model equation including motion equation and error, signal processing filter algorithm on high frequency bandwidth with eliminates error using estimation of error coefficient method is was designed and the prototype inertial sensor showed the pick off noise up to 0.2 mV and bias error performance of about 0.06 deg/hr by the experiments. Accordingly, we confirmed that the design of inertial sensor was valid for high rotation.

• 드라이브 ㆍ 컨트롤
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• 제17권1호
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• pp.44-50
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• 2020

For the requirement of accurate tracking control and the safety of physical human-robot interaction, torque control is basically desirable for humanoid robots. Because of the complexity of humanoid robot dynamics, the TDC (time-delay control) is practical because it does not require a dynamic model. However, there occurs a considerable error due to discontinuous non-linearities. To solve this problem, the TDC-FLC (fuzzy logic compensator) is applied to humanoid robots. The applied controller contains three factors: a TDE (time-delay estimation) factor, a desired error dynamic factor, and FLC to suppress the TDE error. The TDC-FLC is easy to execute because it does not require complicated humanoid dynamic calculations and the heuristic fuzzy control rules are intuitive. TDC-FLC is implemented on the whole body of a humanoid, not on biped legs even though it is performed by a virtual humanoid robot. The simulation results show the validity of the TDC-FLC for humanoid robots.

• 한국군사과학기술학회지
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• 제11권6호
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• pp.55-62
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• 2008

An Estimation of VHF datalink range for EW(Electronic Warfare) equipment in the sea environment was studied to predict the datalink range between transmitting and receiving station. We consider refraction and reflection in addition to the basic radar equation. The reflection especially includes propagation factor in case of spherical earth as well as flat earth. The estimation result can predict the real datalink range within 5% error.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.716-724
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• 2008

In the case of subsea tunnels, hydro-mechanical coupled analysis is necessary for an exact design and construction. The consideration of the overstretched ground condition is also required because they are usually located at the great depth unlike the usual tunnels. Many researches have been performed on the estimation of relaxed rock mass height. However, there have been no researches on the estimation of relaxed rock mass height under overstretched ground conditions. In this study, therefore, hydro-mechanical coupled analyses were performed under the overstressed ground conditions and the relaxed rock mass heights were estimated based on the contour of the local safety factor around a tunnel.

• 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.

• 산업기술연구
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• 제30권A호
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• pp.3-8
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• 2010

Recently, There have been many attempts to optimize energy usage in buildings and houses using Information Technology(IT) and the typical implementation can be found in Intelligent Building and Zero Energy Building. These kinds of buildings need to forecast the building loads, estimate the capacity requirement for power supply, and decide the capacity of the main transformer of the building. Currently, the capacity of the main transformer has been decided just using typical load estimation method not considering the load characteristics and patterns. In this paper, we propose a new load estimation method considering the load characteristics and patterns of the builiding. The proposed method was applied to actual mail center and verified the feasibility of application to actual design of buildings.