• Journal of the military operations research society of Korea
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• v.22 no.1
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• pp.30-42
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• 1996

This study deals with an optimal firecar location and allocation models under uncertain enemy attack at the airforce base. It allocates just one firecar on the runaway and the other firecars on the headquarter of firecar company in usual situation. It is possible for several facilities at the airforce base to be attacked simultaneously by missiles enemy air attacker, other things under uncertain enemy attack. We formulate two stochastic LP location-allocation models to deal with uncertainty. One model is to locate all firecars on one site like present situation. We generate a new firecar location with a weighted average method. We call this model "centralized allocation model". The other model is to distribute firecars on several possible sites. We call this model "distributed allcoation model". Finally, we compare two models with computer experimentations on 8 airforce bases.on 8 airforce bases.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.211-218
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• 1998

In start-up process control applications it may be necessary to limit the sample size to one measurement. A control chart for individual measurements is used whenever it is desirable to examine each individual value from the process immediately. A possible option would be to use an exponential weighted moving(EWM), using modifying statistics with individual measurement, chart for monitoring the process center, and using a moving range (MR) chart for monitoring process variability. In this paper it is shown that there is scheme in using the EWM procedure based on average run length. An expression for the ARL is given in terms of an integral equation, approximated using numerical quadrature. In this case, where it is reasonable to assume normality and negligible autocorrelation in the observations, provide graphs that simplify the design of EWM-MR chart and taking method of exponential smoothing constant(λ) and constant(K) are suggested. The charts suggested above evaluate using the conditional probability.

• IE interfaces
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• v.20 no.2
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• pp.94-102
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• 2007

Portfolio management deals with decision making on 'when' and 'how' to revise an existing portfolio. In this paper, we show that a classical statistical process control (SPC) chart for normal data, a wellestablished tool in quality engineering, can effectively be used for signaling times for revising a portfolio. Noting that the day-to-day performance of a portfolio may be auto-correlated, we use the exponentially weighted moving average center-line chart to develop an automatic portfolio management procedure. The portfolio management procedure is extensively tested on historical data of equities traded in the Korea Exchange (KRX), the American Stock Exchange (AMEX), and the New York Stock Exchange (NYSE). In comparison with the performances of the KOSPI, XAX, and NYA indices during the same time periods, results from these experiments show that SPC chart-based portfolio revision presents itself a convenient and reliable method for optimally managing portfolios.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.73-76
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• 2018

A Gaussian noise is caused by surrounding environment or channel interference when transmitting image. The noise reduces not only image quality degradation but also high-level image processing performance. The Non-Local Means (NLM) filter finds similarity in the neighboring sets of pixels to remove noise and assigns weights according to similarity. The weighted average is calculated based on the weight. The NLM filter method shows low noise cancellation performance and high complexity in the process of finding the similarity using weight allocation and neighbor set. In order to solve these problems, we propose an algorithm that shows an excellent noise reduction performance by using Summed Square Image (SSI) to reduce the complexity and applying the weighting function based on a cosine Gaussian kernel function. Experimental results demonstrate the effectiveness of the proposed algorithm.

• Annual Conference of KIPS
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• 2013.11a
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• pp.320-322
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• 2013

무선센서네트워크에서 MAC 프로토콜은 듀티사이클을 이용하여 센서노드의 에너지 소비를 줄임으로써 배터리의 수명을 연장한다. 기존에 제안된 TA (Traffic-Adaptive)-MAC 프로토콜은 비동기 방식 기반으로 듀티사이클을 조절하여 센서노드의 에너지 소비를 줄인다. 본 기법은 네트워크의 트래픽 상태를 고려하여 동적으로 센서노드의 듀티사이클을 조정한다. 이러한 방법으로 센서노드의 대기시간을 줄이고 센서노드의 에너지를 효과적으로 사용한다. 하지만 이 기법은 네트워크의 트래픽 변화가 잦은 환경에서는 좋지 못한 효율을 보인다. 따라서 본 논문에서는 기존의 TA-MAC 기법에 가중이동평균 방법을 적용하여 합리적인 듀티사이클 선정을 위한 트래픽 계산 방법을 제안한다. 이는 최근 트래픽 값과 현재 감지한 트래픽의 평균을 계산하고 다음 트래픽을 예측하여 네트워크 트래픽이 급격히 변화하는 불안정한 환경에서 더 합리적인 듀티사이클 선정을 돕는다.

• The Korean Journal of Applied Statistics
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• v.29 no.7
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• pp.1271-1281
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• 2016

Wins above replacement (WAR) is one of the most widely used statistic among sabermatrics statistics that measure the ability of a batter in baseball. WAR has a great advantage that is to represent the attack power of the player and the base running ability, defensive ability as a single value. In this study, we proposed a hitter ability index using the sabermetrics statistics that can replace WAR based on Korea Baseball Record Data of the last three years (2013-2015). First, we calculated Batter ability index through the arithmetic mean method, the weighted average method, principal component regression and selected the method that had high correlation with WAR.

• Journal of Welding and Joining
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• v.14 no.6
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• pp.131-139
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• 1996

The response of the arc sensor using the welding current and/or welding voltage as its outputs has been obtained by the analysis and/or experiments of the static characteristics of arc sensor. But in order to improve the reliability of arc sensor, it is necessary to know its dynamic characteristics. So in this paper, it is presented the dynamic model of arc sensor including the power source, arc voltage, electrode burnoff rate, and wire feed rate. A numerical simulation of the dynamic model of arc sensor was implemented, computing the welding current with input of CTWD. The results of computer simulations and experiments of $CO_2$arc welding showed that a linear relationship between weaving center - weld line distance and current area difference was established. Additionally, a real-time weld seam tracking system interfaced with industrial welding robot was constructed, the result of the weld seam tracking experiment for weld line with an initial offset error of 5$^{\circ}$was good.

• Journal of the Korean Institute of Gas
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• v.10 no.4 s.33
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• pp.52-62
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• 2006

In this study, we tried to propose a selection method of release scenarios and a method of consequence analysis at a gas explosion by pipe release. Thus, release rates, damage areas of the facilities, and fatality areas were estimated and analyzed at various release conditions(temperature, pressure, release material, etc). As a results, we could conclude that the rupture was the worst case of release scenarios, and at release rates and damage areas were better estimated by the weighted average method considering a generic failure frequency of the release hole than by an arbitrary selection of the release hole.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.2
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• pp.1-10
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• 1993

Frequency response functions(FRF) are the most fundamental data for the frequency domain identifications of structural systems. In this paper, an improved method for estimating FRF's is presented. The new FRF estimator takes the weighted average of two conventional estimators, $H_1$(f) and $H_2$(f), utilizing the fact that $H_2$(f) gives more accurate estimate at resonance, while $H_1$(f) yields better results at antiresonances. Based on the estimated FRF's, the modal parameters of the structures, such as, natural frequencies, damping ratios and mode shapes, are also estimated. The effectiveness of the proposed method is investigated through numerical and experimental studies. The estimated results indicate that the proposed estimator gives more accurate results than other estimators.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.91-98
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• 2009

For maintaining railroad, accumulated passing tonnage is a determinant factor of appropriate rail replacement time. Recently, Seoul Metro's rail maintaining system and technology is being improved from previous years, which increasing a standard of rail replacement. Thus, this brings importance of estimating and managing for accumulated passing tonnage. In case of light weighted train such as subway, current method of calculating accumulated passing tonnage has defaults of misrepresenting accumulated passing tonnage data. Because current method is based on the weight of passengers and train., and operation data. In addition, currently there is no mechanical and electronic system that could represent and support the accurate data between heavy and non-heavy traffic area, and accumulated passing tonnage is calculated inaccurately by estimating average value each line. The current method of calculating accumulated passing tonnage misleads to unpredictable data that represent inappropriate rail replacement period, which leads to under or over analyzed replacement period. If accumulated passing tonnage is over estimated, rail replacement leads to waste of budget. Hence, it is necessary to construct reliable actual measurement system to manage rail's life safely and efficiently, and in this study the accumulated passing tonnage measurement device is installed with using rail pad of optical fiber sensors and its effect is analyzed.