• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.614-620
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• 2005

Ensemble에서 feature selection은 각 classifier의 학습할 데이터의 변수를 다르게 하여 diversity를 높이며, 이것은 일반적인 성능향상을 가져온다. Feature selection을 할 때 쓰는 방법 중의 하나가 Genetic Algorithm (GA)이며, GA-SVM은 GA를 기본으로 한 wrapper based feature selection mechanism으로 response model과 keystroke dynamics identity verification model을 만들 때 좋은 성능을 보였다. 하지만 population 안의 후보들간의 diversity를 보장해주지 못한다는 단점 때문에 classifier들의 accuracy와 diversity의 균형을 맞추기 위한 heuristic parameter setting이 존재하며 이를 조정해야만 하였다. 우리는 GA-SVM 알고리즘을 바탕으로, population안 후보들의 fitness를 측정할 때 accuracy와 diversity 둘 다 고려하는 fitness function을 도입하여 추가적인 classifier 선택 작업을 제거하면서 성능을 유지시키는 방안을 연구하였으며 결과적으로 알고리즘의 복잡성을 줄이면서도 모델의 성능을 유지시켰다.

• Journal of Biosystems Engineering
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• v.26 no.3
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• pp.237-244
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• 2001

This work was intended to investigate the effect of vibration transmission paths on the ride vibration of tractor during the rotavating and transporting operations by applying the vibration path analysis method. Accelerations at the cab mounts were measured during the rotavating and transporting operations. Ride vibrations at the sear were than calculated using the measured accelerations at the cab mounts, and the frequency response functions and inertances between the seat and cab mounts, which were derived experimentally by the impact hammer test in static condition. The human sensitivity to vibration frequency was also taken into consideration for the calculation of ride vibrations at the 1/3 octave center frequencies in the frequency domain. Vibrations transmitted through rear cab mounts affected more significantly the ride vibration of tractor. The peak accelerations at the seat occurred at the frequencies of the engine and crank speed, and the frequency induced by tire lugs on the road transportation. It was found that the rear cab mounts should be improved in order to reduce the ride vibrations more effectively.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.11-14
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• 2001

A systematic construction and re-use of technology related to the product development and production has been the most important for the semiconductor industry dependent on process and equipment. Therefore, numerous outputs in the form of paper has been produced in the process of information management ranging from the creation to recycling and disposal of technologies. In this research, the technology and documents necessary for the business management in the field of semiconductor manufacturing were classified in an effort to solve problems while the modeling of document management architecture at the enterprise level was performed by properly setting up the security system to prevent the unauthorized disclosure of the product development technology to the third parties. Especially, the product and process specification are designed in such a way as to ensure a real-time response in interface with the production system in order to shorten the development lead-time and improve the productivity. This paper is to discuss the modeling approach, the strategy to construct the system and its results.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.195-203
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• 2007

In this paper, an analytic model of sleep model operation in the IEEE 802.16e is investigated. A mobile subscribe. station (MSS) goes to sleep mode after negotiations with the base station (BS) and wakes up periodically for a short interval to check whether there is downlink traffic to it. If the arrival of traffic is notified, an MSS returns to wake mode. Otherwise, it again enters increased sleep interval which is double as the previous one. In order to consider the situation more practically, we propose the sleep mode starting threshold, during which MSS should await packets before it enters the sleep mode. By modifying the M/G/1 with multiple vacations model, energy consumption ratio(ECR) and average packet response time are calculated. Our analytic model provides potential guidance in determining the optimal parameters values such as sleep mode starting threshold, minimal sleep and maximal sleep window.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.477-481
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• 2007

The purpose of this study is to provide the ideal forecasting model of cadastral survey work load through the Economeatric Analysis of Time Series, Granger Causality and VAR Model Analysis, it suggested the forecasting reference materials for the total amount of cadastral survey general work load. The main result is that the derive of the environment variables which affect cadastral survey general work load and the outcome of VAR(vector auto regression) analysis materials(impulse response function and forecast error variance decomposition analysis materials), which explain the change of general work load depending on altering the environment variables. And also, For confirming the stability of time series data, we took a unit root test, ADF(Augmented Dickey-Fuller) analysis and the time series model analysis derives the best cadastral forecasting model regarding on general cadastral survey work load. And also, it showed up the various standards that are applied the statistical method of econometric analysis so it enhanced the prior aggregate system of cadastral survey work load forecasting.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.4
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• pp.1-9
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• 2013

We propose a heuristic algorithm for war-game model that is appropriate for warfare in which the maneuver of the attacker is relatively certain. Our model is based on a multi-weapon extention of the Lanchester's square law. However, instead of dealing with the differential equations, we use a multi-period linear approximation which not only facilitates a solution method but also reflects discrete natures of warfare. Then our game model turns out to be a continuous game known to have an ${\varepsilon}$-Nash equilibrium for all ${\varepsilon}{\geq}0$. Therefore, our model approximates an optimal warfare strategies for both players as well as an efficient reinforcement of area defense system that guarantees a peaceful equilibrium. Finally, we report the performance of a practical best-response type heuristic for finding an ${\varepsilon}$-Nash equilibrium for a real-scale problem.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.7
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• pp.863-871
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• 2007

This paper proposes a methodology to estimate the system coefficients for the infinite impulse response(IIR) digital filters using real code GA. In the traditional real coded GA, it adapts the general genetic operations, whereas in this paper the proposed real coded GA applies improved genetic operations in order to search the optimal solution in given problems. Each of unknown IIR digital coefficients collected as forms of a chromosome. Two illustrative examples including the band pass and band stop IIR digital filters are demonstrated to verify the proposed method.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.394-398
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• 1994

The aim of the present study was to determine the influence of vibration frequency and muscle contraction level at constant vibration displacement amplitudes on a commonly observed motor response elicited by local vibratory stimulation, i.e., the Tonic Vibration Reflex (TVR). Vibration was applied to the distal tendons of the hand flexor muscles. Changes in activity of the hand flexor and extensor muscles were analyzed as a function of the vibration frequency (40-200 Hz), displacement amplitude(200.mu.m and 300.mu.m peak-to-peak), and the initial contraction level of the flexor muscles (0%, 10%, and 20% of the maximal voluntary contraction: MVC). The main results indicate that the TVR increases with vibration frequency up to 100-150 Hz and decreases beyond, and the TVR attains its maximum at 10% MVC. It appears that high frequency vibration tends to induce less muscle/tendon stress. Such a result is of particular importance for the design of handheld vibrating tools.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1071-1078
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• 2006

Robust design of products or processes is a way to produce products or processes with less variability on condition that the product specification is met, so that the ratio of nonconforming products can be as minimized as possible. In such models as robust parameter design(RPD) originated by Taguchi and response surface methodology(RSM), the variances of noise variables are assumed to be measurable. However, there are circumstances in which the experimenters are unable to measure noise variables or perhaps are not aware of what the noise variables are. In this paper, it is demonstrated through an example that Taguchi's RPD approach can be conducted within the framework of the analysis of variability, with a view to a comparison of the two methods.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.531-534
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• 2006

Response surface methodology (RSM) is a useful collection of experimentation techniques for developing, improving, and optimizing products and processes. When we are to estimate second-order regression model and optimize quality characteristic by RSM, central composite designs and Box-Behnken designs are widely in use. However, in developing cutting-edge products, it is very crucial to reduce the time of experimentation as much as possible. In this paper small-sized second-order designs are introduced and their estimation abilities are compared in terms of D-optimality, A-optimality, and variance of regression coefficients, ease of experimentation, number of experiments. Then we present a guideline of using specific designs for specific experimentation circumstances. The result of this study will be beneficial to experimenters who face experiments which are expensive, difficult, or time-consuming.