• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.4
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• pp.24-32
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• 2009

For a design of on/off solenoid actuator for valve actuating, designer must have the experimental knowledge as well as general electromagnetic formulas to design object. It is possible for theoretical knowledge to do the out-line design, but it is impossible to optimal design without experimental knowledge which only can be achieved through many repeated experiments. In addition, in present on/off type solenoid actuator field, the smaller, lightening, lower consumption power, high response time are effected as the most important design factor. So, experimental knowledge is more needed for optimal design of solenoid actuator. In this study, we derived the governing equations for optimal design of on/off solenoid actuator for valve actuating and developed a design program composed electromagnetic theories and experimental parameter values for inexperienced designers. And we proved the propriety of this program by experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.10
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• pp.1499-1504
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• 2013

As oil price and demand for environment friendly vehicle rapidly increase, research on electric car is being widely carried out. Especially, NEV(Neighborhood Electric Vehicle) is a pollution-free vehicle that can be mass-produced which the time of development for related technologies is urgently needed. In this paper the On-Board charger for mid- and large- sized secondary cell is applicable in aerospace and other general industries, and the Off-Board standing charger is expected to be employed in creating charging infrastructure.

• The Korean Journal of Emergency Medical Services
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• v.16 no.1
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• pp.81-90
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• 2012

Objectives: This study is to research delay time comparison for later defibrillation after hands off according to the changes in defibrillation electrodes. Study purpose: In defibrillation treatment that is the only way for cardiac arrest by arrhythmia, it is to find defibrillator device which can minimize late defibrillation delay time after important affect of hands off. Study object and method: After hands off according to the defibrillator device, we collected total 40 people for emergency medicine doctor, internal medicine doctor, general surgeon, nurse, emergency medical technician who are working at 2 CN, CS University hospitals in Gwangju Jeollanamdo district to find out hand off shock interval(HOSI). We then researched their general properties like occupation sector, experiences in clinic, gender, completion of AHA ACLS-P training and more. Then 40 participants continued ventricular fibrillation cardiac arrest simulation training (using human-model mannequin) designed by researcher and performed their roles as defibrillation operator. Each of participant used manual paddle and performed 4 times of defibrillation (150J) during 8 minutes of CPR and in 8day, the defibrillator devices were replaced from manual paddle to self-adhesive electrodes pads and 4 times of defibrillation (150J) under same simulation condition as manual paddle were performed. Study result: In comparison for delay time of later defibrillation after hands off of manual paddle and self adhesive electrodes pad, the self adhesive electrodes pad ($7.0{\pm}0.5sec$) seemed to reduce delay time of later defibrillation significantly (p<0.05) compared to manual paddle ($10.0{\pm}0.9sec$). The self adhesive electrodes pad, according to the general properties of participants, had no particular change in delay time after later defibrillation for the statistics (p>0.05) but the manual paddle had statistically significant differences for the occupation sector, experiences in clinic and gender (p<0.05). Conclusion: In defibrillation, the self adhesive electrodes pad($7.0{\pm}0.5sec$) showed short HOSI compared to manual paddle ($10.0{\pm}0.9sec$) significantly (p<0.05) and it applied identically for both existence and non-existence of ACLS-P training completion, experiences in clinic, gender and occupation sector. The manual paddle had also significant difference in experiences in clinic and occupation sector (p<0.05). which means the effect on HOSI according to the job mastery. Therefore, if the clinic experience is short or in case for the occupations without frequent defibrillation treatment has a danger of lowering success rate for the defibrillation using manual paddle. Therefore, it is true that using self adhesive electrodes pad for defibrillation electrodes when performing manual defibrillation in pre-hospital as well as in-hospital steps can generally minimize delay time of later defibrillation after hands off.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.99-109
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• 2007

The purpose of the study is to examine the effect of the spring shoe through the comparison of spring shoe to general shoe. For this, 12 healthy females in the age from 20 to 30 years participated in the E.M.G. experiment with testing kinematic variables. Results indicated that there was significant differences in angle of ankel between the general and spring shoe. Specifically, the spring shoe showed a bigger angle of take on and a smaller angle of take off in walking than the general shoe. This mesns that the spring shoe does not have a significant effect to produce efficient and smooth walking. In addition, the spring shoes revealed a bigger rear-foot angle than the general shoe in the evaluation of rear-foot control function. This means that the rear-foot control function of the spring shoe is low compared to trhe general shoe. Meanwhile, there is no significant differences in angle of knee and angle of Achilles tendon between both shoes. In an analysis of E.M.G., the significant differences were found in gastrocnemius muscle, anterior tibial musculi, musculi rectus femoris, biceps muscle of thigh between both the general and spring shoe groups by the section. In the case of gastrocnemius muscle, the spring shoe showed a low muscle production of anterior tibial musculi than the general shoe. This is a result from structural nature of the sole of a foot of the spring shoe. The spring shoe performs a rolling movement through slightly large pronation toward front-foot from rear-foot in supprt time before taking-off of toe and the power for this movement is mainly produced from musculi rectus femoris.

• Korean Journal of Psychosomatic Medicine
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• v.16 no.1
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• pp.31-37
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• 2008

Objectives : There may be methodological differences between pencil-and-paper and web-based questionnaires. But there are few reports about influences of that methodological differences. The Aim of this study is investigation of the differences in temperament characteristics in subjects who answered internet addiction questionnaires. Methods : We compare the characteristics between two groups. Four hundred thirty participants(189 males, 241 females) answered the online and offline questionnaires. We controlled sexes, addiction scores and psychiatric treatment histories using general linear model of MANCOVA. Results : There were statistically significant differences in temperament characteristics between two groups. Harm avoidance(HA) and novelty seeking(NS) scores were significantly higher in on-line group than off-line group. Reward dependence(RD) scores were significantly lower in on-line group than off-line group. Conclusion : This study suggested significant differences of temperament characteristics between on-line and off-line subjects. And there have been many studies on equivalence of on-line and off-line survey methods. Further studies on the difference are expected for the understanding of this results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.735-737
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• 2017

An Off grid or remote solar electric systems are an energy supply to our home or to our companies without the utility of Grid at all. Off grid solar systems are very important for those who live in remote locations especially for developing countries where getting the electric grid is extremely expensive, inconvenient or for those who doesn't need to pay a monthly bill with the electric bill in general. The main critical components of any solar power system or renewable energy harvesting systems are the energy storage systems and its charge controller system. Energy storage systems are the essential integral part of a solar energy harvesting system and in general for all renewable energy harvesting systems. To provide an optimal solution of both high power density and high energy density at the same time we have to use hybrid energy storage systems (HESS), that combine two or more energy storage technologies with complementary characteristics. In this present work, design and simulation we use two storage systems supercapacitor for high power density and lithium based battery for high energy density. Here the system incorporates fast-response supercapacitors to provide power to manage solar smoothing and uses a battery for load shifting. On this paper discuss that the total energy throughout of the battery is much reduced and the typical thermal stresses caused by high discharge rate responses are mitigated by integrating supercapacitors with the battery storage system. In addition of the above discussion the off grid solar electric energy harvesting presented in this research paper includes battery and supercapacitor management system, MPPT (maximum power point tracking) system and back/boost convertors. On this present work the entire model of off grid electric energy harvesting system and all other functional blocks of that system is implemented in MATLAB Simulink.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.119-121
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• 2014

In general, high temperature combustion technique has been adopted as an efficient one. However, hydrocarbon-based fuel can be decomposed under high temperature, and it can affect the stabilization mechanism of edge flame. In this research, basic experimental study was conducted to identify the effect of fuel pyrolysis on the lift-off flame stabilization by changing the temperature of the plug flow reactor. Schmidt number of the gas fuel can be changed with temperature variation due to the fuel pyrolysis. Eventually, this study will help to establish and clarify the stabilization mechanism of lift-off edge flame.

• International Journal of Air-Conditioning and Refrigeration
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• v.7
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• pp.22-32
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• 1999

A multi-type heat pump controls the mass flow rate of the working fluid to cope with variable heat loads when it is under dynamic load condition. This paper describes the exergy analysis associated with the unsteady response of a heat pump. First, a basic heat pump cycle is examined at a steady state to show the general trends of exergy variations in each process of the cycle. Entropy generation issue for the heat exchangers is discussed to optimize the heat pump cycle. Secondly, the performance of the inverter-driven heat pump is compared to that of the conventional one when the heat load is variable. Thirdly, the exergy destruction rate of the heat pump with On/Off operation is calculated by simulating the thermodynamic states of the working fluid in the condenser and the evaporator. The inefficiency of On/Off operation during the transient period is quantitatively described by the exergy analysis.

• Proceedings of the KSRS Conference
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• v.1
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• pp.263-266
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• 2006

Now, on the developing COMS(Communication, Ocean and Meteorological Satellite) has solar panel on the South panel only. Therefore, the wheel off-loading has to be performed periodically to reduce a induced momentum energy by a asymmetric solar panel. One of two East/West station keeping maneuver to correct simultaneously longitude and eccentricity, orbit corrections may be performed during one of the two wheel off-loading manoeuvres per day to get enough observation time for meteorological and ocean sensor. In this paper, we applied a linearized orbit maneuver equation to acquire maneuver time and delta-V. Nonlinear simulation for the station keeping is performed and compared with general station keeping strategy for fuel reduction.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.3
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• pp.175-179
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• 2015

In this study, we propose Ti hole pattern structure on the transparent conductive oxide (TCO) less dye-sensitized solar cells (DSSCs) using the lift-off process to improve the low light transmittance and low efficiency caused by opaque Ti electrode. The formation of Ti hole patterns make it possible to move the dye adsorption and electrolyte. The DSSCs with Ti hole patterns showed a higher photoelectric conversion efficiency (PCE) than those with general structure by 11.1%. As a result, The Ti hole pattern structure can be improved to increase the light absorption of the dyes and PCE of the TCO-less DSSCs is also increased.