• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.117-121
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• 2002

A numerical model that describes the reductive dechlorination of tetrachloroethene(PCE) to ethene via cis-dichloroethene(CDCE) was developed. The model included two separated dehalogenator groups : one for PCE transformation to cDCE via TCE and the other for cDCE dehalogenation to ethene via VC, competitive inhibition between different chloroethene electron accepters, and competition for H$_2$ between dechlorination and methanogens. Model simulations suggest first, that PCE dechlorinators are better competitive with methanogens than cDCE dechlorinators. Second, not only the initial relative population size of dehalogenators and H$_2$-utilizing methanogens but also electron donor delivery strategies used greatly affects the degree of dehalogenation. As a result, all of factors in the above must be considered in order to achieve economical and successful bioremediation of contaminated soil and groundwater with chlorinated solvents.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.4
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• pp.551-560
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• 1998

This paper presents a neural network model representing complex hydro-thermo-dynamic characteristics of a steam generator in nuclear power plants. The key modeling processes include training data gathering process, analysis of system dynamics and determining of the neural network structure, training process, and the final process for validation of the trained model. In this paper, we suggest a training data gathering method from an unstable steam generator so that the data sufficiently represent the dynamic characteristics of the plant over a wide operating range. In addition, we define the inputs and outputs of neural network model by analyzing the system dimension, relative degree, and inputs/outputs of the plant. Several types of neural networks are applied to the modeling and training process. The trained networks are verified by using a class of test data, and their performances are discussed.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.4
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• pp.253-263
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• 2002

This paper presents an adaptive feedback linearization control scheme for induction motors using stator fluxes. By using stator flukes as states, overparameterization is prevented and control inputs can be determined straightforwardly unlike in existing schemes. This approach leads to the decrease of the relative degree for the flux modulus and thus yields a simpler control algorithm than the prior results. In this paper. adaptation schemes are suggested to compensate for the variations of stator resistance. rotor resistance and load torque. In particular, the adaptation to the variation of stator resistance with a feedback linearization control is a new trial. In addition, to improve the convergence of rotor resistance estimation, the differences between stator currents and its estimates are used for the parameter adaptation. The simulations show that torque and flux are controlled independently and that the estimates of stator resistance, rotor resistance, and load torque converge to their true values. Actual experiments on a 3.7㎾ induction motor verify the effectiveness of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.9
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• pp.1322-1331
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• 1989

This paper proposes a new adaptation algorithm with which a model reference adaptive control can give a local boundedness of the tracking error applied to a continuous-time linear time-invariant single-input single-output plant whose reduced-order model is of relative degree 1 and whose unmodeled dynamics may be represented in a sigular perturbation form. With the addition of an offset term and an extra adaptation structure, this algorithm is shown to have a robustness property in the sense that this gives zero residual tracking errors when the unmodeled dynamics are disappeared.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.2
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• pp.123-130
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• 1989

In order to investigate the biocompatibility of base metal alloys in dental prosthesis, the 3 types of Ni-Cr alloys and the 3 types of Co-Cr alloys were collected and each alloy was extracted in the culture medium. L-cells derived from the subcutaneous tissue of mouse and extracted medium were cultivated. The relative growth rate of L-cells in the tissue culture was calculated with N-R assay. The obtained results were as follows: 1. In the case of the Co-Cr alloys tested, its cytotoxicity proved weak. 2. In the case of the Ni-Cr alloys tested, there was no significant degree of cytotoxicity, especially 25% Victory was proved noncytotoxicity.

• IE interfaces
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• v.11 no.1
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• pp.23-32
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• 1998

This paper presents a model for assessing the efficiency of logistics activities in distribution centers. The DEA approach is adopted to compare the relative efficiency of distribution centers, where considered as input and output factors are warehouse floor area, field storage area, average inventory level, overhead costs, number of workers, number of orders, and total value of goods handled. The artificial neural network approach is also adopted to overcome the limitation of DEA. The 12 distribution centers of Korea Telecom are studied for the validation of the model, which results in 84.9% of learning accuracy. This model can be used to identify the inefficient factors in a distribution center and to reveal changes in the degree of efficiency over time.

• Journal of the Korean Society of Safety
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• v.12 no.1
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• pp.113-121
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• 1997

Human reliability attempts to make precise quantitative analyses and predictions of the performance of human-machine(or product) systems. In order to yield more precise human error analysis, precise human error probabilities(HEPs) must be used in the analysis. However, because human behavior is influenced by factors that are called performance shaping factors(PSFs), the effects of PSFs must be considered to obtain precise HEPs, These are called basic HEPs or situation-specific HEPs. This paper presents a theoretical method for obtaining basic HEPs (i.e. , considering PSFs) in quantitative human error analysis. In this method, the weight which characterizes the degree of importance of several PSFs is obtained by the analytic hierarchy process. The quality scores of PSFs in the task situation are obtained by percentile concept. These scores are used in conjunction with the relative Importance weights of PSFs to compute the composite quality percentile score of PSFs in the task situation. Then, a new mapping method of the composite quality percentile score of PSFs into a situation-specific basic HEP is proposed with a numerical example.

• Journal of the Korean Home Economics Association
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• v.40 no.5
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• pp.15-24
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• 2002

The following research conclusions were made, relative to the experiments of the textiles of fire fighters Protective Clothing. 1. When the body protection efficiency such as the thickness, the strength and heat resistance are considered, Nomex(N) is tuned out the best outer shelf, Gore-tex(KG) the best moisture barrier, and Wool-felt(WC) the best thermal barrier. 2. In the hygienic and sanitary efficiency also, N is turned out the best outer shelf, KG the best moisture barrier, and WC the best thermal barrier in its degree of water resistance, water vapour permeability, and air permeability. 3. In the washing and maintenance efficiency, too. N is turned out the best outer shell, KG the best moisture barrier, and WC the best thermal barrier, being considered the material's rate of contraction, the changing rate of frame resistance, water resistance, and water vapour permeability. 4. When considered the frame resistance against the reflection tape and reflection efficiency, O is the best material for it marks the highest score in the frame resistance and reflective effect.

• Journal of the Korean Home Economics Association
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• v.35 no.5
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• pp.221-238
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• 1997

The purpose of this study is to investigate the factors which influence on the propensity for pro-environmental consumer behavior. the data used in this study included 712 married women living in Seoul and Kwangju. Statistics used for data analysis were Reliability, t-test, one-way Anova, and Multiple Regression Analysis. According to the results of the regression, the relative importance of variables are in order of; pro-environmental behavior degree of reference group, residential district, ecological value orientation, economic value orientation, convenience-centric value orientation, type of dwelling, the adequacy of community resource, education experience of environment and their explanatory power totalled 30.35%. The result of this study coude be attributed to develop the environmental policy and education program to enhance of pro-environmental behavior. First, Economic approach and ecological approach toward the environmental affairs are not incompatible; indeed, they are may be related. I resume that both of two alternatives are useful to environment policy. And, environmental education be effectively related to pro-environment behavior, life-education and sysmatic support must be provided.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1187-1192
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• 2008

In this paper, a versatile multi-objective optimization concept for fatigue life prediction is introduced. Multi-objective decision making in engineering design refers to obtaining a preferred optimal solution in the context of conflicting design objectives. Compromise decision support problems are used to model engineering decisions involving multiple trade-offs. These methods typically rely on a summation of weighted attributes to accomplish trade-offs among competing objectives. This paper gives an interpretation of the decision parameters as governing both the relative importance of the attributes and the degree of compensation between them. The approach utilizes a response surface model, the compromise decision support problem, which is a multi-objective formulation based on goal programming. Examples illustrate the concepts and demonstrate their applicability.