• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.9
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• pp.587-592
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• 2015

In this study, the electrification voltage of electrostatics for silicone rubber sample($4cm{\times}4cm{\times}0.103cm$) following immersion with contaminants of 2 ml, 5 ml, 10 ml for six hours has been measured in through the applied voltage of 10 kV DC at temperature of $80^{\circ}C{\sim}110^{\circ}C$, humidity of 50%~90%. The results of this study are as follows. In case the contaminants is constant, it found that the electrification voltage of electrostatic decreased with increasing temperature and humidity to $35^{\circ}C$, 90%. In case of 2 ml of contaminants concentration, it found that the electrification voltage of electrostatic decreased with increasing temperature and humidity to $35^{\circ}C$, 50%. In case of the sample at temperature of $15^{\circ}C$ and humidity of 50%, it found that the electrification voltage of electrostatic decreased with increasing contaminants to 10 ml.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.711-713
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• 1996

This paper proposes a unit commitment scheduling method based on Genetic Algorithm(GA). Due to a variety of constraints to be satisfied, the search space of the UC problem is highly nonconvex, so the UC problem cannot be solved efficiently only using the standard GA To efficiently deal with the constraints of the problem and greatly reduce the search space of the GA, the minimum up and down time constraints are embedded in the binary strings that are coded to represent the on-off states of the generating units. The violations of other constraints arc handled by integrating penalty factors. To show the effectiveness of the GA based unit commitment scheduling, test results for system of 5 units are compared with results obtained using Lagrangian Relaxation and Dynamic Programming.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.823-825
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• 1996

This paper proposes a preventive maintenance scheduling system which is a user-friendly decision-making support system. The objective of the development of the package is to supply KEPCO's working experts with a useful tool for gaining a practical maintenance schedule. This program based on the MS Windows is made up of two main modules. The first is an interactive decision-making support module(IDSM). The main objective of this module is to provide various useful text and graphic information to users, and enable practicing engineers with sensitivity analysis of a targeting maintenance schedule. The second is a mathematical optimization module(MOM). In this module, the objective function of levelizing net reserve ratio with daily time-increment is optimized using the relaxation method.

• Journal of Korean Physical Therapy Science
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• v.16 no.4
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• pp.1-9
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• 2009

Background: The purpose of this study is to find out the effect on the improvement in idiopathic scoliosis when applying the orthopedic manual physical therapy and myofascial release technique. Methods: 20 patients in Cheon-An ${\bigcirc}{\bigcirc}$ hospital were selected as subjects whose Cobb's angle were higher than $10^{\circ}$ according to the radiograph. They were treated for 60 minutes a day, three days a week, and 8 weeks so that the total time of visit would be 24. We performed five tests (Moire test, X-ray, standing height test, Cobb's angle, pelvic level test, VAS) to indentifiy the therapeutic effects. Results: Four test results were improved more remarkably after those treatment than before(p<.001), except pelvic level test (p>.001). Conclusion: we confirmed that there were correcting effects on most of the valuation index from the primary analysis, which divided the subjects into 2 groups by Cobb's angle, but there were more effective in patients having lower than $25^{\circ}$. There were similarly correcting effects on most of the valuation index according to the secondary analysis, but there were particularly more effective in children.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.105-110
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• 2006

Study for toner adhesion is 3non as an important role in electrophotography. In this research, a centrifugal detachment method was used to measure the adhesion force of several hundred particles simultaneously and to determine its sensitivity to particle size. For uncharged toner particles, we estimated the van der Waals force based on the centrifugal force experiments. Then for charged toner particles, the centrifugal force experiments were carried out. The difference between the results for charged toner particles and the results for uncharged toner particles was compared with the image force calculated from a model which assumed that the toner charge was located at the center of the particle. In the calculations, experimental data obtained by E-SPART (Electrical-Single Particle Aerodynamic Relaxation Time) analyzer were used. The adhesion force of micro-sized toner particles deposited on the DR surface was found to be approximately $1{\sim}3$ nN.

• IE interfaces
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• v.20 no.2
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• pp.186-194
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• 2007

Recent deregulation of Korean electricity industry has made each power generation company pay more attention to maximizing its own profit instead of minimizing the overall system operation cost while guaranteeing system security. Electricity power generation problem is typically defined as the problem of determining both the on and off status and the power generation level of each generator under the given fuel constraints, which has been known as Profit-Based Unit Commitment (PBUC) problem. To solve the PBUC problem, the previous research mostly focused on devising Lagrangian Relaxation (LR) based heuristic algorithms due to the complexity of the problem and the nonlinearity of constraints and objectives. However, these heuristic approaches have been reported as less practical in real world applications since the computational run time is usually quite high and it may take a while to implement the devised heuristic algorithms as software applications. Especially when considering long-term planning problem which spans at least one year, the complexity becomes higher. Therefore, this paper proposes an explicit column generation algorithm using power generation patterns and the proposed algorithm is successfully applied to a Korean power generation company. The proposed scheme has a robust structure so that it is expected to extend general PBUC problems.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.7
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• pp.515-521
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• 2013

Magnetoelectric(ME) bulk composites with PZT-PNN-PZN/$Fe_2O_4$ were prepared by using a conventional ceramic methods and investigated on the ME voltage vs frequency of ac magnetic fields. We made the electric equivalent circuits by using the Maxwell-Wagner model and simulated the frequency dependence of ME voltage in low frequency region. ME devices were described by a series of two equivalent circuits of piezoelectric and magnetic, which have the relaxation time ${\tau}$ due to the interaction between ME device and load resistor. Equivalent circuit of piezoelectric material is independent of frequency. However ferrite magnetic materials have Debye absorption and dipolar dispersion, whose equivalent circuit is a function of frequency. Therefore we suggest the resistance in the equivalent circuit is proportion to $1+{\omega}^2{\tau}^2$ and the capacitance is in inverse proportion to $1+{\omega}^2{\tau}^2$ in the magnetic materials.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.207-214
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• 2014

Mass and flow resistance in a square ribbed microchannel have been studied numerically using the Lattice Boltzmann Method. It has been build up on two dimensional nine velocity vectors model with single relaxation time method called the Lattice Bhatnagor-Gross-Krook model. To analyze the roughness effect on the flow resistance namely the friction factor and mass flow has been discussed at the slip flow regime, $0.01{\leq}Kn{\leq}0.10$, where Kn is the Knudsen number. The wall roughness is considered by square microelements with a relative roughness height up to maximum 10% of channel height. The velocity profiles in terms of streamlines near the riblets are demonstrated to be responsible for the roughness effect. It is found that the roughness effect leads to increase the flow resistance with roughness height but it is decreased significantly with increasing the space between two roughness elements as well as the Knudsen number. In addition, the mass flow decreased linearly with increasing both roughness height and gap but significantly changed at the slip flow regime.

• Journal of Oriental Neuropsychiatry
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• v.22 no.4
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• pp.77-86
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• 2011

Objectives : These days assaults and other natural and human disasters are increasing. But oriental medical treatment researches in Korea are limited in car accident PTSD patients only. Our object is to explore an oriental medical intervention model for the evidence-based approach to PTSD after diverse trauma including disasters. Methods : Domestic papers for Korean researches are obtained from oriental medical related journals by internet searching. International materials are obtained from PubMed searching and a publication from Department of Veterans' Affairs. After assorting searched articles into RCTs and non-RCTs, we analyzed the articles according to the elapsed time from trauma. Results : We confirmed that acupuncture, CBT, and PMR were effective in acute stage after traumatic event. And EMDR, EFT, and relaxation therapy were effective in chronic stage after traumatic event. Building on the findings, we proposed a model of oriental medicine for Disaster Mental Health. Conclusions : Analyzing previous researches about oriental medicine on PTSD, several interventions were confirmed the effectiveness on specific treatment stage. We could find the possibility of Oriental Medicine as a Disaster Mental Heath and proposed a model of Oriental medicine for Disaster Mental Health.

• Biomolecules & Therapeutics
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• v.2 no.2
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• pp.136-140
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• 1994

To prove the hypothesis that NO- and N $O_2$-carrying molecules potentiate photorelaxation by generating NO, investigation was carried out using isolated rabbit and human corpus cavernosum. Corporal smooth muscle, in the presence or absence of endothelium, relaxed only slightly upon ultraviolet light (366 nm) irradiation. But, NO-and/or N $O_2$-containing compounds such as streptozotocin and $N^{G}$-nitro-L-arginine methyl ester significantly (p<0.01) enhanced photorelaxation in this tissue. In addition, $N^{G}$-nitro-D-arginine methyl ester, known to lack inhibitory action on NO synthase, showed concentration-dependent potentiation of the photorelaxation. Oxygen radical generating system via copper＋ascorbic acid and guanylate cyclase inhibitor, methylene blue, significantly (p<0.05) inhibited the streptozotocin-potentiated photorelaxation. Nitrite was accumulated by photolysis of streptozotocin, $N^{G}$-nitro-L-arginine methyl ester and $N^{G}$-nitro-D-arginine methyl ester, in a concentration and exposure time dependent manner. These observations indicate that NO is a potent relaxant of rabbit and human corpus cavernosum and further support the hypothesis that NO is released by photolysis from NO- and N $O_2$-carrying molecules.lecules.