• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.97-102
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• 2005

This paper presents feed rate optimizaton of a PMLSM driven feed-slide for mininum vibrations by smoothing velocity curve with finite jerk. First of all, the PMLSM was designed and made to reduce detent force. Next, a PMLSM driven feed-slide system was mathematically modeled as a 4-degree-of-freedom lumped parameter model. The key idea of our vibration minimization method is to find out the most appropriate smooth velocity curve with finite jerk. The validity of our proposed method has been verified by comparing computer simulation results of the feed-slide model with experimental ones.

• Journal of the Korea Safety Management & Science
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• v.8 no.3
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• pp.125-141
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• 2006

If do not become whole optimization because enterprise's individual enterprise internal determinate improvement effort is associated with activity in enterprise SCM, competitive power can not but be extremely limited the result. Therefore, to spur in hidden cost's discovery and logistics' optimization is actuality. In this paper, as long as it is by logistics cost except empty driving if reverse logistics happens in distribution channel progressing, logistics reverse logistics' hidden cost through model that do minimization profit of logistics to look for plan that can do maximization try. Finally, is based on dual of distribution cost and profit of logistics and reverse logistics and achieves Pull, optimal system modeling that use Push system and gropes method of effective logistics cost.

• Journal of the Semiconductor & Display Technology
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• v.3 no.3
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• pp.41-44
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• 2004

The aim of this study is the confirmation of the coating uniformity affected by the surface tension and wall attachment angle in a slit-coater model. In this work, we use the commercial code (Fluent) to solve the two-phase flow formed with air and photo resist numerically. The results show that the surface tension is the most important factor to determine the coating efficiency in the view of coating uniformity, and the coating uniformity is 2% for our slit-coater model and conditions. To improve the coating uniformity, it is in need of minimization of the sidewall effect of slit-coater.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.178-185
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• 1999

Minimum life-cycle cost helps to evaluate cost effectiveness of base-isolated bridges under specific condition. Life-cycle cost mainly consists of the initial construction cost and the expected damage cost. Damage cost estimation needs proper model of input ground motion failure probability evaluation method and limit states definition. We model the input ground motion as spectral density function compatible with the response spectra defined at each seismicity and site condition. Spectrum analysis and crossing theory is suitable for reseating calculation of failure probabilities in the process of cost minimization. Limit states of base-isolated bridges re defined for superstructure isolator and pier respectively The method is applied to both base-isolated bridges and conventional bridges under the same conditions to investigate cost effectiveness of base isolation in low and moderate seismic region. the results show that base-isolation of bridges are more effective in low and moderate seismic region and that the site effects on the economical efficiency may not be negligible in such a region.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.465-468
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• 2002

An unconstrained tuning fork with a 3-D model has been numerically analyzed by Finite Element Method (FEM) and Boundary Element Method (BEM). The first three natural frequencies were calculated by the FEM modal analysis. Then the change of the modal frequencies was examined with the variation of the tuning fork length and width. Analytical model equations were derived from the numerically relating results of the modal frequency-tuning fork length by approximating minimization. Finally the BEM was used for the sound pressure field calculation from the structural displacement data.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.241-245
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• 2015

In this work we present the results of light curve analysis for two cataclysmic variables detected recently in the SDSS project: SDSS J090350.73+330036.1 and J150240.98+333423.9. Photometric observations of the first were obtained during a superoutburst in May 2010. Our observations clearly indicate the presence of superhumps in the light curves, suggesting SDSS J090350.73+330036.1 is an SU UMa dwarf nova. We determined the period of the superhumps. We also carried out fitting using a spiral-arm model in order to determine parameters of the accretion disk, hot line, and other components of this system. Photometric observations of the second, J150240.98+333423.9, were obtained during the post-maximum decline, during April-June 2012. Photometric variability of this system has been studied in an inactive state. We obtained its parameters via a combined model fitted to the observed light curves by ${\chi}^2$ minimization.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.1
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• pp.1-9
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• 2002

The thermal response of electronic components during infrared reflow soldering is studied by a two-dimensional numerical model. The convective, radiative and conduction heat transfer within the reflow oven as well as within the card assembly are simulated. Parametric study is also performed to determine the thermal response of electronic components to various conditions such as conveyor velocities, exhaust velocities and emissivities. The results of this study can be used in selecting the oven operating conditions to ensure proper solder melting and minimization of thermally induced card assembly stresses.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.4
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• pp.89-97
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• 2011

Traditional quality control for manufacturing or service sector is not suitable for the quality control of a project as the project is one-time task constrained by time, cost, and quality. To meet the internal and external customers' requirements, quality costs approach to the project will be effective. Hence, we propose PONC (price of nonconformance) estimation procedure and a mathematical model, which are focused on activity-based prevention in the execution step and warranty step of EPLC (extended project life cycle). This procedure and model will help project manager develop preventive action plan for project quality costs minimization from nonconformance risk activities and PONC estimates information.

• Water for future
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• v.23 no.1
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• pp.109-118
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• 1990

In this study, the effectiveness of existing streamflow data collection networks in the Han and the Nakdong River Basin is evaluated for various gaging plans of 5, 10, 15 and 20years planning horizons by the nonlinear integer programming method, and also a technique for adjustment and planning of the existing network is provided for the purpose of increasing the efficiency of the network in terms of ecomony. The objective function is minimization of the average sampling mean square error of regional regression model with regression parameters estimated by generalized least squares method.

• Journal of Information Processing Systems
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• v.10 no.1
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• pp.119-131
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• 2014

In recent literature on traffic scheduling, the combination of the two-dimensional discrete-time Markov chain (DTMC) and the Markov modulated Poisson process (MMPP) is used to analyze the capacity of VoIP traffic in the cognitive radio system. The performance of the cognitive radio system solely depends on the accuracy of spectrum sensing techniques, the minimization of false alarms, and the scheduling of traffic channels. In this paper, we only emphasize the scheduling of traffic channels (i.e., traffic handling techniques for the primary user [PU] and the secondary user [SU]). We consider the following three different traffic models: the cross-layer analytical model, M/G/1(m) traffic, and the IEEE 802.16e/m scheduling approach to evaluate the performance of the VoIP services of the cognitive radio system from the context of blocking probability and throughput.