• Journal of applied mathematics & informatics
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• v.13 no.1_2
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• pp.247-259
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• 2003

Optimal control problem for the exploitaton of oil is investigated. The optimal control problem under consideration in this paper is governed by weak coupled parabolic PDEs and involves with pointwise state and control constraints. The properties of solution of the state equations and the continuous dependence of state functions on control functions are investigated in a suitable function space; existence of optimal solution of the optimal control problem is also proved.

• Journal of Acupuncture Research
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• v.30 no.2
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• pp.55-63
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• 2013

Objectives : This study was performed to examine the effectiveness of auricular acupuncture to adult men on smoking cessation. Methods : 47 smoking people was divided two groups : experimental group(treated with auricular acupuncture therapy, n=22) and control group(not treated with auricular acupuncture therapy, n=25). We used Lung point, Shenmen point and Endocrine point twice a week for 4 weeks to experimental group. We assessed the changes in amount of daily smoking, desire of smoking, taste of smoking and nicotine dependence as well as subjective symptoms were studied. Results : The experimental group showed significant decrease in amount of daily smoking, desire of smoking, taste of smoking and nicotine dependence. Subjective symptoms also showed improvement comparing to control group. Conclusions : Acupuncturing lung, shenmen, and endocrine point showed effectiveness on decreasing smoking rates and subjective symptoms. Therefore the auricular acupuncture therapy is expected to helpful to smoking cessation and improve the health of smokers.

• Asia pacific journal of information systems
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• v.24 no.2
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• pp.115-140
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• 2014

In a dynamic business environment, the enterprise mobility solution for a mobile office (EMS) has been adopted to increase the competitive edge of organizations. By using an EMS, performance is expected to be enhanced. However, the related literature has paid little interest to the impact of system quality in an EMS on the information quality produced by the system. On the basis of socio-technical theory, we posited that the system quality in an EMS influences information quality. In addition, we investigated the relationships between the above two qualities, use and job performance by considering task mobility and task inter-dependence as control variables. Survey respondents were from many industries using EMSs. The result of structural equation modeling shows that system quality positively affects information quality, and other relationships in the model are proven statistically significant. We also found that system quality has stronger impacts on use and job performance than information quality does in EMS. However, system quality does not affect use in case both task mobility and task inter-dependence exist. The theoretical and practical implications of the result are discussed in the paper.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.2
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• pp.85-91
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• 2015

A gasoline engine automobile uses high voltage generation of the ignition coil, igniting and burning mixed fuel in the combustion chamber, which drives the engine. When the electronic control unit intermits a current supplied to the power transistor, counter electromotive force with a low voltage is generated by self induction action in the ignition primary coil and a high voltage is induced by mutual induction action with the primary ignition coil in the second ignition coil. The high voltage is supplied to the ignition plug in the combustion chamber, causing a spark, igniting the compressed mixed fuel. If a very small defect occurs inside the insulating material when a voltage is applied in said ignition coil, the performance of the insulation material will get worse and breakdown by a partial discharge of corona discharge. Thus, in this experiment, we are to contribute to improve the performance and ensure the reliability of the ignition coil by investigating partial discharge characteristics according to the change of voltage and temperature when a voltage is applied to the specimen of the epoxy molding ignition coil.

• Nuclear Engineering and Technology
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• v.21 no.3
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• pp.151-164
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• 1989

Since in the KMRR the neutron spectrum is hardened in comparison with the conventional power reactors, and the absorber is in a tube-form which may contain the neutron multiplying media inside it, the reactor physics characteristics of the KMRR absorber are much different. The characteristics of the hafnium control absorber are studied under the several kinds of the environmental conditions. The environmental conditions include the inner materials inside the absorber shroud, the absorber thickness, the absorber burnout, and the fuel burnup. Investigated are nuclear characteristics such as the dependence of the spectral, regional, and isotopic contribution to the neutron absorption, and the dependence of the reactivity worth. Many important absorber characteristics are identified and presented from the analysis.

• Journal of Korean Medical Ki-Gong Academy
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• v.13 no.1
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• pp.105-144
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• 2013

This study intended to provide fundamental data to take countermeasures against recurrent stress by analyzing the health-related quality of life and factors for recurrent stress of alcohol dependents. Structured questionnaire was prepared for patients who quitted drinking after they had been hospitalized for alcohol dependence to take medical treatment but suffered recurrence, and analysis on health-related quality of life and environmental factors with drinking risk was conducted. The quality of life was at a relatively satisfactory level, where pain was found at the highest level and general health condition was found at the lowest level. Environmental factors with drinking risk were found to be a moderate level, drinking for the reason of family and friends in terms of complications with other persons was found to be highest, and then job, self control, bad emotions, and social pressure on drinking were found in order. For health-related quality of life, the quality of life was found to be high in case of the only son, professional job, well-educated persons, and no history of hospitalization. Regarding factors for recurrent stress, stress was found to be high in case of the eldest son and being without religion, and the lower was the quality of life, the higher were recurrent stress and environmental factors with drinking risk. It was found that demographic factors including age, marriage, and job influenced the recurrence of alcohol dependence, and factors for recurrent stress, etc. also influenced recurrent alcohol dependence with drinking risks. Specially, the lower was the quality of life, the higher were factors for recurrent stress, and drinking risks, therefore measures to improve the quality of life are required to be taken to prevent alcohol dependence from recurrence.

• Journal of the Korean Magnetics Society
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• v.21 no.2
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• pp.52-55
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• 2011

Spin-transfer torque is a useful tool to control the magnetic state in nanostructures. In magnetic tunnel junctions, the spin-transfer torque has two components, the in-plane spin torque and the perpendicular spin torque. While properties of the in-plane spin-transfer torque are relatively well understood, properties of the perpendicular spin-transfer torque still remain controversial. A recent experiment demonstrated that in asymmetric magnetic tunnel junctions, the bias voltage dependence of the perpendicular spin-transfer torque contains both linear and quadratic terms in the bias. However it still remains unexplored how the bias voltage dependence changes as a function of material parameters. In this paper, we systematically investigate the perpendicular spin-transfer torque in asymmetric magnetic tunnel junction by varying spin splitting energy, work function difference, and Fermi energy of the ferromagnetic metal leads.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.827-832
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• 2022

In this study, the effect of fear of COVID-19 on children's ability in life competency was examined, and the mediating effect of smartphone dependence on this relationship was also verified. For this study, 250 children living in area K who were using smartphones were surveyed as research subjects. The major research results found that the higher the fear of COVID-19, the lower the child's ability in life competency, which affects the child's ability in life competency. And the fear of COVID-19 has been shown to affect smartphone dependence. In addition, It was found that dependence on smartphones had a fully mediating effect on the relationship between children's fear of COVID-19 and their ability in life competency. Based on these research results, to promote the healthy growth and development of children in social disaster crises such as COVID-19, a convergence intervention and pro-active strategy that can control children's smartphone dependence and improve their life's ability in life competency was presented.

• Journal of KSNVE
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• v.8 no.3
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• pp.485-493
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• 1998

Many of the adaptive noise control systems utilize a form of the least mean square (LMS) algorithms. In the active control of noise, it is common practice to locate an error microphone far from the control source to avoid the near-field effects by evanescent waves. Such a distance between the control source and the error microphone makes a certain level of time-delay inevitable and, hence, may yield undesirable effects on the convergence properties of control algorithms such as filtered-x LMS. This paper discusses the dependence of the convergence rate on the acoustic error path in these popularalgorithms and introduces new algorithms which increase the convergence region regardless of the time-delay in the acoustic error path. Performances of the new LMS algorithms are presented in comparison with those by the conventional algorithms based on computer simulations and experiments.

• Journal of Magnetics
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• v.11 no.4
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• pp.156-159
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• 2006

We have studied the magnetic properties of the CuNi nanoparticles for three different sizes prepared by plasma and chemical techniques. The magnetization is enormously enhanced with decreasing the nanoparticle size. This enhanced magnetic moment shows almost inversely linear temperature dependence, which could be interpreted by the Langevin-type superparamagnetism. The field dependence exhibits ferromagnetic-like behavior with weak hysteresis, which could described in terms of uncompensated spin and/or surface anisotropy. In addition, the magnetic data suggest that the CuNi nanoparticles produced by the plasma method result in significantly less oxidized metallic nanoparticles than those prepared by other techniques.