• 대한안전경영과학회지
• /
• 제3권4호
• /
• pp.135-144
• /
• 2001

The capital cost of the company is one that must be paid to the money owner as the price by using the money. The capital cost according to the source of money supply can be estimated by the expected profit rate undertaken by the use of the capital. But in the area of pre-existent economic evaluation, the evaluation of the company investment has been treated by the profit rate of the capital after considering the repayment conditions of the other's money or the interest. Thus in this study, in case the company makes an investment on various kinds of the capital at the same time, not make use of the capital as a one source, the economic evaluation of an investment should be handled by taking the weighted average cost of capital into consideration in proportion to the constitution of the capital cost by the sources of money supply, Especially, as the cost of the private money is very much connected with the profit rate through the stock market, the Capital Asset Pricing Model (CAPM) will be applied. This kind of economic evaluation method can be said to have much to do with the Economic Value Added : EVA) as well as to be highly thought as a standard to estimate the company' value recently To certify the usefulness of this approach, the case study of the output of the capital cost will be made for the purse of the economic evaluation of the alternative investment by using the financial statements of a motor company H.

• Nuclear Engineering and Technology
• /
• 제55권10호
• /
• pp.3907-3912
• /
• 2023

Radiation portal monitors (RPMs) installed at airports and harbors to prevent illicit trafficking of radioactive materials generally use large plastic scintillators. However, their energy resolution is poor and radionuclide identification is nearly unfeasible. In this study, to improve isotope identification, a RPM system based on a multi-array plastic scintillator and convolutional neural network (CNN) was evaluated by measuring the spectra of radioactive sources. A multi-array plastic scintillator comprising an assembly of 14 hexagonal scintillators was fabricated within an area of 50 × 100 cm². The energy spectra of ¹³⁷Cs, ⁶⁰Co, ²²⁶Ra, and ⁴K (KCl) were measured at speeds of 10-30 km/h, respectively, and an energy-weighted algorithm was applied. For the CNN, 700 and 300 spectral images were used as training and testing images, respectively. Compared to the conventional plastic scintillator, the multi-arrayed detector showed a high collection probability of the optical photons generated inside. A Compton maximum peak was observed for four moving radiation sources, and the CNN-based classification results showed that at least 70% was discriminated. Under the speed condition, the spectral fluctuations were higher than those under dwelling condition. However, the machine learning results demonstrated that a considerably high level of nuclide discrimination was possible under source movement conditions.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 추계학술대회논문집
• /
• pp.371-371
• /
• 2006

The purpose of this study is to provide a fundamental data for efficient and economical reduction method and predict ion method of floor impact noise. In order to get the useful results, the measurement on the vibration transmission characteristics of standard test building with four rooms by using heavy and light-weighed impact source were carried out. In this measurement various conditions such as the change of test structure construction, the pick-up sensor location, the excitation posit ion, and the resilient material types were applied to get the vibration characteristics transmitted from excitation room to adjacent rooms.

• 한국전자통신학회논문지
• /
• 제16권3호
• /
• pp.407-416
• /
• 2021

능동위상배열안테나는 적절한 급전신호 가중치 선택에 따라 대국을 향해 주 빔을 조향할 수 있을 뿐만 아니라 간섭원 방향으로 패턴 널을 형성할 수 있다. 주 빔의 조향을 위한 급전신호 가중치는 방사소자의 위치를 기반으로 쉽게 산출할 수 있다. 그리고 패턴 널 형성을 위한 급전신호 가중치 또한 적절한 요구 방사패턴 설정과 WLSM(Weighted Least Squares Method)을 이용하면 산출할 수 있다. 그러나 일반적인 무선 통신망 환경에서 간섭원의 위치는 미인지 상황에 있다. 따라서 적응형 패턴 널 형성 기법이 필요하다. 본 논문에서는 요구 방사특성 설정에 따른 패턴 널 형성이 가능함을 확인하고, 이를 기반으로 관측 영역 기준 이진탐색 알고리즘을 이용하여 간섭원 적응형 패턴 널 형성 기법에 관하여 연구하였다. 제시된 기법을 기반으로 모의실험을 수행한 결과, 효율적으로 간섭 적응형 패턴 널 형성이 가능함을 확인하였다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.1191-1196
• /
• 2007

This research presents a laboratory study about an annoyance of impulsive sound caused by construction site(breaker and blasting). The sources are sampled from outdoor noise and their levels range from 40 to 75 dB at the interval of 5dB. The noise unit is based on A-weighted sound exposure level (ASEL; $L_{AE}$). To make equal ASEL of outdoor noise, finite impulse response (FIR) filter is applied to the originally sampled source to include the effect of distance attenuation. The evaluation method of jury test adopted a Semantic Difference Method (SDM). In the result of the Jury test for impulsive noise, the annoyance response of blasting noise was higher than that of breaker noise.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2002년도 학술발표회 발표논문집
• /
• pp.453-456
• /
• 2002

In this study, the effect of DEM resolution (15m, 30m, 50m, 70m, 100m, 200m, 300m) on the hydrological simulation was examined using BASINS (Better Assessment Science Integrating point and Nonpoint Source) for Heukcheon watershed (303.3km2) data from 1998 to 1999. Generally, as the cell size of DEM increased, topographical changes were observed as the original range of elevation decreased. The processing time of watershed delineation and river network needed more time and effort on smaller cell size of DEM. The larger DEM demonstrated had some errors in the junction of river network which might effects on the simulation of water quantity and quality. The area weighted average watershed slope became lower but the length weighted average channel slope became higher as the DEM size increased. DEM resolution affected substantially on the topographical parameter but less on the hydrological simulation. Considering processing time and accuracy on hydrological simulation DEM mesh size of 100m is recommended for this watershed.

• 로봇학회논문지
• /
• 제7권2호
• /
• pp.142-149
• /
• 2012

The camera has limitations of poor visibility in underwater environment due to the limited light source and medium noise of the environment. However, its usefulness in close range has been proved in many studies, especially for navigation. Thus, in this paper, vision-based object detection and tracking techniques using artificial objects for underwater robots have been studied. We employed template matching and mean shift algorithms for the object detection and tracking methods. Also, we propose the weighted correlation coefficient of adaptive threshold -based and color-region-aided approaches to enhance the object detection performance in various illumination conditions. The color information is incorporated into the template matched area and the features of the template are used to robustly calculate correlation coefficients. And the objects are recognized using multi-template matching approach. Finally, the water basin experiments have been conducted to demonstrate the performance of the proposed techniques using an underwater robot platform yShark made by KORDI.

• 대한전기학회논문지
• /
• 제41권2호
• /
• pp.144-155
• /
• 1992

A design of a highly stable current-controlled power supply combining the phase-controlled rectifier (PCR), passive filter and active filter is investigated. A digital phase-looked voltage control (PLVC) with a capability of compensating the thyristor firing angles under unvalanced power source is proposed` otherwise the PCR output voltage has low-order subharmonics whose suppression requires a bulky passive filter. The digital PLVC has a fast dynamic characteristics as an inner control loop of the PCR. To suppress further the output ripple, an active filter using a transformer is introduced and its design is described through the frequency domain analysis. An optimal integral, proportional and measurable variable feedback (IPM) controller is designed using the time-weighted performance index based on the time domain analysis. The design method based on the time-weighted performance index gives better response characteristics than that based on the conventional performance index. It is also shown via experimental results that the proposed scheme gives better response characteristics than that based on the conventional performance index. It is also shown via experimental results that the proposed scheme gives good dynamic and static performances.

• 말소리와 음성과학
• /
• 제7권4호
• /
• pp.17-25
• /
• 2015

For blind source separation of convolutive mixtures, FDICA(Frequency Domain Independent Component Analysis) algorithms are generally used. Since FDICA algorithm such as Sawada FDICA, IVA(Independent Vector Analysis) works on the frequency bin basis with a natural gradient descent method, it takes much time to converge. In this paper, we propose a new method to improve convergence speed in FDICA algorithm. The proposed method reduces the number of iteration drastically in the process of natural gradient descent method by applying a weighted inner product constraint of unmixing matrix. Experimental results have shown that the proposed method achieved large improvement of convergence speed without degrading the separation performance of the baseline algorithms.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 춘계학술대회논문집
• /
• pp.714-720
• /
• 2008

This research presents a laboratory study about an subjective response of impulsive sound caused by leisure shooting. The sources are sampled from outdoor noise and their levels range from 40 to 75 dB at the interval of 5dB. The noise unit is based on A-weighted sound exposure level (ASEL; $L_{AE}$). To make equal ASEL of outdoor noise, finite impulse response (FIR) filter is applied to the originally sampled source to include the effect of distance attenuation. The evaluation method of the jury test adopted a Semantic Difference(SD) Method. In the result of the jury test for impulsive noise, the mean response rating expressed a linear relation and %HA(percent highly annoyed) displayed a exponential growth relation.