• Journal of Power System Engineering
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• v.11 no.3
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• pp.22-28
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• 2007

Liquefied gas vaporizer is a machine to vaporize liquefied gas such as liquid nitrogen($LN_{2}$), liquefied natural gas(LNG), liquid oxygen($LO_{2}$) etc. For the air type vaporizer, the frozen dew is created by temperature drop (below 273 K) on vaporizer surface. The layer of ice make a contractions on vaporizer. The structure analysis on the heat transfer was studied to see the effect of geometric parameters of the vaporizer, which are length 1000 mm of various type vaporizer. Structure analysis result such as temperature variation, thermal stress and thermal strain have high efficiency of heat emission as increase of thermal conductivity. As the result, Frist, With-fin model shows high temperature distribution better than without-fin on the temperature analysis. Second, Without-fin model shows double contractions better then with-fin model under the super low temperature load on the thermal strain analysis. Third, Vaporizer fin can be apply not only heat exchange but also a stiffener of structure. Finally, we confirm that All model vaporizer can be stand for sudden load change because of compressive yield stress shows within 280 MPa on thermal stress analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.1
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• pp.42-47
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• 2014

Adequate relative humidity is needed in the common living space, for human health, and industrial space, for maintenance and efficiency. Evaporative humidifier systems generally have slow response tendencies of air loads, but relatively low initial investment and maintenance costs. Humidification efficiency in the evaporative humidifier is dependent mostly on the shapes and arrays of humidifying modules. So, we tried to apply the computational fluid dynamics to the evaporative humidifier systems, and studied the humidification efficiency of evaporative humidifiers, through the outlet air conditions.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.1
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• pp.19-22
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• 2017

This paper describes the efficient equipment maintenance that can offer the exact time for repair and change of component in root industry. A conventional method offered the fixed time for repair and change of component because the method is based on early guarantee specification of the component. However the operating condition of manufacturing field is often under worse condition than early guarantee condition for high productivity. So, most components can't use until early guarantee time due to the operation of various different condition. Therefore we suggest the useful method for efficient equipment-maintenance by manufacturing-field analysis and feedback database. For this, the classification of root industry and related equipment is performed and then the detail classification of the process and component for equipment maintenance. And the monitoring module is also designed to gather data for feedback process and the environment is basically implemented for aging and reliability test.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.249-257
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• 2004

Drying and curing characteristics of PCM resins using the induction heater and short-wave infrared emitter module was studied to develop a compact oven system for the high speed CCL and post-treatment equipment. Drying of the polyester resins using the induction heater and infrared heater showed that the blistering tendency of polyester resin coating increased regardless of additives and colors of resins as the heating rate and/or dry film thickness increased. The blistering of polyester resin coating layer occurred when the heating speed was over than $25^{\circ}C/sec$ for the dry film thickness of $19\~20um$, which is the typical thickness of finish coating in CCL. So did it when the heating speed was over than $40^{\circ}C/sec$ for the dry film thickness over than 10 um. The heating efficiency of paint coated steels by the infrared heating was strongly dependent on the colors of paint coating and generally increased for the dark surface and/or coating. But the faster drying of the PCM resin coatings increased the blistering tendency of coating layer. The blistering limit for the typical finish coating by the infrared heating was estimated as the heating rate slower than $20^{\circ}C/sec$ regardless of colors of PCM resins.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.205-207
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• 2003

In this paper, we propose novel, small and integrated microwave chip filter using high dielectric substrates. A variety of dielectric substrates can be selected for the specifications of products according to dielectric, Q-factors, temperature stability ect. This paper describes an application of the very high dielectric constant (K=133) substrate for design of a band pass filter to a 5.8GHz Transmitter/receiver(T/R) module.

• The Korean Journal of Emergency Medical Services
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• v.16 no.1
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• pp.31-51
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• 2012

Purpose: This study was to develop PBL packages geared toward fostering the problem-solving ability, self-directed learning capability and communicative competence of emergency medical technician students and to give some suggestions on the development of PBL packages of the approach based on the evaluation results of the packages by experts. Methods: First, real clinical situations that learners would be exposed to after graduation should be provided as examples when the packages are developed. Second, a variety of learning-facilitating tools should be offered to facilitate their understanding, because they don't yet gain plenty of clinical practice experiences. Third, they should be encouraged to have an energetic discussion in small group when the developed packages are applied. Conclusion: First, the packages developed in this study were just incorporated into some areas of a single course. In the future, the integration of an entire course or the development of a new course is required to attain the multiple learning objectives in the provided clinical situations. Second, this study attempted to develop the PBL packages to boost the problem-solving ability, self-directed learning capability and communicative competence of emergency medical technician students, and follow-up research should be implemented to finalize the packages based on the suggestions of the experts who evaluated them and to determine the effects of the packages.

• The Korean Journal of Emergency Medical Services
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• v.22 no.2
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• pp.23-33
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• 2018

Purpose: To investigate the perception of paramedic students about core competence and methods of disaster response. Methods: A self-reported questionnaire was completed by 210 paramedic students in Jeollado from March 2 to April 2, 2018. It comprised 57 questions on topics such as general characteristics (6), related experience (11), cognition of core competence (15), and knowledge of disaster response methods (25). Data were analyzed by means of a frequency analysis, a t-test, an ANOVA, and the Pearson's correlation coefficient using SPSS WIN 21.0. Results: The average score of the participants on disaster response core competence was 3.21. The statement "In case of a disaster, I know the duties of medical staff" scored the second highest, at 3.58, and "In the case of disaster, I can conduct the basic treatment" scored the highest ar 3.59. The average score for the disaster response methods was 3.31. Within the section, the statement "I know what I need to do in the case of burn patients" scored 3.59 and "I know what I need to do in the case of a cardiac arrest patient" scored the highest at 3.93. Conclusion: It is necessary to develop a training module considering the diverse types of disasters and a standardized education program for simulation similar to real-life situations.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.2
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• pp.95-101
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• 2014

In this paper, UPS, with a built-in instantaneous sag drop compensation features, was developed to improve performance. The improved UPS, using instantaneous moving average method, compensates by quickly measuring the voltage and series inverter of half-bridge type, using line-interactive method that links with the voltage of the battery and power source, was developed. In addition, by developing a parallel inverter that uses a high-efficiency PWM switching method, overall UPS system was enhanced. To verify the performance of the proposed algorithm, single-phase 5[kVA] UPS systems were designed and the experimental system was constructed. The low-cost type of Cortex-M3 module CPU STM32F103R8T6 (32[bit]) is attached and the switching time of mode transfer was set within 4 [ms]. THD of the linear load operates in less than 3[%], and the stability of the output voltage operates in approximately ${\pm}2[%]$ range. The superior performance of the operations was confirmed with the system set as above.

• Bulletin of the Korean Mathematical Society
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• v.29 no.2
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• pp.265-275
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• 1992

The characteristic free representation theory of the general linear group has found a wide range of applications, ranging from the theory of free resolutions to the symmetric function theory. Representation theory is used to facilitate the calculation of explicit free resolutions of large classes of ideals (and modules). Recently, K. Akin and D. A. Buchsbaum [2] realized the Jacobi-Trudi identity for a Schur function as a resolution of GL$_{n}$-modules. Over a field of characteristic zero, it was observed by A. Lascoux [6]. T.Jozefiak and J.Weyman [5] used the Koszul complex to realize a formula of D.E. Littlewood as a resolution of schur modules. This leads us to further study resolutions of Schur modules of a particular form. In this article we will describe some new classes of finite free resolutions associated to the Pieri type skew Young diagrams. As a special case of these finite free resolutions we obtain the generalized Koszul complex constructed in [1]. In section 2 we review some of the basic difinitions and properties of Schur modules that we shall use. In section 3 we describe certain exact complexes associated to the Pieri type skew partitions. Throughout this article, unless otherwise specified, R is a commutative ring with an identity element and a mudule F is a finitely generated free R-module.e.

• Journal of Korea Multimedia Society
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• v.23 no.2
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• pp.282-292
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• 2020

In order to minimize casualties from marine vessel accidents that occur frequently at home and abroad, it is important to ensure the safety of the passengers aboard the vessel in the event of an accident. There is an EPIRB system as a system for disaster preparedness in the marine situation currently on the market, but there is a problem that the price is very expensive. In order to overcome the cost problem, which is a disadvantage of previous system, LoRaWAN-based communication is used. LoRaWAN communication-based vessel positioning and risk detection system based on LoRaWAN communication transmits measurement data of each module using two Beacon and GPS modules to stably perform position measurement for both indoor and outdoor situations. The rider danger situation detection system can detect the safety status of the rider using the 3-axis acceleration sensor, collect data from the rider positioning system and the rider safety status detection system, and send to server using LoRa communication. When conducting communication experiments in the long-distance maritime situation and actual communication experiments using the implemented system, it was found that the two experiments showed over 90% communication success rate on average.