• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.3.2-3.2
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• 2009

Microfluidics and BioMEMStechnology has increasingly been used as a tool for studying small volumes oftissue and even individual cells. One of the most important benefits ofmicrofluidic technology is the potential to build devices that analyze and sortmammalian cells. The "sorting problem" typically requires that a fewcells be selected and isolated from a larger population of hundreds, thousandsor even millions of other cells. For example, cancer tumor cells may resideamong a large population of healthy cells, but it would be of great interest toidentify, isolate and study only the cancer cells. In another application, onemay want to determine the number of white blood cells within a sample of blood.We have developed microfluidic devices that enable researchers to select cellsfrom a population by a variety of methods, including antibody staining,dielectrophoretic selection, and physical size selection. These devices haveapplications in cancer research where cancer cells must be identified fromnormal tissue, but where only small samples of tissue are available. In thistalk, we will present some of our microfluidic cell sorting devices, discusstheir physical principles, and their use in biological applications.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.3
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• pp.299-311
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• 1995

Conventional discounted cash flow techniques fail to capture the risk associated with investments. This paper proposes an annual cash flow model that considers risk, cost structure and inventory liquidation in the evaluation of investment alternatives. The risk differential of investments is included using the capital asset pricing model while the stochastic version of the cost-volume-profit approach is used to consider inventory liquidation and cost structure. Tradeoffs between fixed and variable costs have been investigated, and portrayed using iso-cash flow curves. The proposed cash flow model has been developed, in particular, to enable an accurate evaluation of advanced manufacturing systems.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.4
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• pp.741-754
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• 1997

Code matrix is the matrix of which on element and its neighbors are arranged to have a code value. The code matrix was originally designed by the author for developing a vision system but has not been theoretically studied. In this paper some theoretical properties of the code matrix are investigated. The studied characteristics of the code matrix are useful for not only understanding the matrix itself but efficiently restructuring the matrix. A number of transformation functions, which enable the matrix to have different shape, are thus developed based on the investigated properties. The transformation functions are then applied to build a perfectly and uniformly structured square code matrix, which is proven useful in on image processing example. The study in this paper is expected to serve a theoretical background for the application of the code matrix in many areas.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.357-361
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• 1990

PSPICE is a general purpose circuit program that can be applied to simulate and calculate the performance of electronic circuits. More recently, an ideal voltage controlled switch provided in it is proposed to develop simple computer models for SCR's and TRIAC's. These models enable designer to simulate the steady state and transient analysis of power electronics circuit.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.1 s.151
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• pp.48-54
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• 2007

Higher productivity and less cost during the manufacturing process of ships are required to maintain international competitiveness of modern shipbuilding industries. The integrated hull/ outfitting/ painting scheduling(IHOP) process is a final point, where logistics are finally being integrated and upcoming schedules are made. Therefore, more profits are expected from IHOP by effective management. In this thesis, IHOP is proposed in order to solve how to choose block erection date with IHOP scheduling logic. The result of IHOP scheduling is highly advised to utilize fabrication, outfitting shops. A standardized operation and load of resource will eventually be applied in long-term time span point of view for this will make it easy to enable capacity planning and workforce planning. It is also expected to eliminate inefficiency in overtime work and efficiently utilize manpower in short-term.

• Journal of environmental and Sanitary engineering
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• v.18 no.4
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• pp.36-44
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• 2003

The cement-based system among S/S(Solidification/Stabilization) is widely used to treat hazardous wastes. In this study, tannery sludge was solidified to evaluate the stabilization effects of using admixtures in the cement-based S/S. Fly ash as substitute also used to increase the strength of the S/S of hazardous waste. The compressive strength measurement and leaching experiment of chromium metal of solidified mortar were carried out to compare and evaluate the physical and chemical characteristics of solidified hazardous waste sludge. From the result of this study, there was increased of compressive strength by using AEW-3(early-hardening AE water reducing agent), and leaching concentration of chromium became low enough to satisfy the regulatory criteria. The successful solidification for the organic contaminant and heavy metal in hazardous waste should enable to treat by cement-based system using early-hardening AE water reducing admixture and fly ash as substituted cement.

• Journal of Preventive Medicine and Public Health
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• v.38 no.3
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• pp.259-266
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• 2005

Recently much attention has been paid to the effect of neighborhood characteristics on the health of individuals, independent of individual demographic and/or socioeconomic characteristics. Although many empirical studies of a kind, mostly based on Western society, have appeared on various international journals, few studies have shown empirical evidence of neighborhood characteristics as an independent and significant risk factor of ill health in Korea. This paper discusses possible reasons that neighborhood seems to be neither significant nor substantial regarding its impact on the health of Koreans. Addressing the uniqueness of Korean society regarding the concept of neighborhood, attributes of neighborhoods, and methodological challenges, authors suggest that more sophisticated conceptual and methodological approach, specific to Korean society, should enable to reveal the effect of neighborhood characteristics on individual health in Korea.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.382-384
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• 2004

In this parer, we propose a clustering that perform algorithm using new convergence properties. For detection and optimization of cluster, we use to similarity measure with cumulative probability and to inference the its parameters with MLE. A merits of using the cumulative probability in our method is very effectiveness that robust to noise or unnecessary data for inference the parameters. And we adopt similarity threshold to converge the number of cluster that is enable to past convergence and delete the other influence for this learning algorithm. In the simulation, we show effectiveness of our algorithm for convergence and optimization of cluster in riven data set.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.147-149
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• 2004

There are no authentic solutions in a face region extraction problem though it is an important part of pattern recognition and has diverse application fields. It is not easy to develop the facial region extraction algorithm because the facial image is very sensitive according to age, sex, and illumination. In this paper, to solve these difficulties, a fuzzy color filer based on the facial region extraction algorithm is proposed. The fuzzy color filter makes the robust facial region extraction enable by modeling the skin color. Especially, it is robust in facial region extraction with various illuminations. In addition, to identify the fuzzy color filter, a linear matrix inequality(LMI) optimization method is used. Finally, the simulation result is given to confirm the superiority of the proposed algorithm.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.690-692
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• 2004

Differently from an existing analog control, because the digital control includes microprocessor basically, the digital control is enable to monitor internal parameters of DC-DC converter and to control output voltage remotely by communicating with a Windows based PC and also to monitor whether exact voltage is output or not. These things are impossible in an analog control. In this paper, a simple flyback converter is taken as a control target and is controlled by a microcontroller(TMS320F2812). This converter can make variable outputs 1.8V to 5V from 30V input voltage remotely in PC. Finally the response characteristics of a step reference voltage and in a steady state are experimented to verify the feasibility and the usefulness of this digital controlled converter.