• Proceedings of the KIEE Conference
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• summer
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• pp.123-125
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• 2004

This paper describes an optimal configuration of Community Energy System (CES) for the multi-energy consumers and analyzes economical feasibility for such system. The most of previous feasibility studies for Co-Generation plants of CES in Korea have shown negative results due to the abnormally low price of power rate in Korea. However, in order to overcome this situation a new approach was examined in this Paper. The efforts of this approach the selection of the low price but reliable facility and maximizing the capacity factor of the facility. MGT was selected in view of low price and good reliability. In order to maximize the capacity factor the system capacity should be quite lower than the actual required Electrical and Heat load of the subject entity. In this report 100 kW Co-Generation facility was selected in view of conservative analysis. The results of the analysis showed that pay back period may vary from 4 to 5 yens according to the application of LNG rates whether it is to-generation rate or the normal business rate. With the analysis in this paper we confirmed that CES is feasible even in Korea if we do not insist to select the capacity of CES to cover all the energy required but select a smaller size of CES compared to the actual requirement, which can allow full load operation of the system continuously.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.8 s.251
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• pp.931-940
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• 2006

Defect assessment of a weld zone is important in fitness-for-service evaluation of plant components. Typically a J and $C^*$ estimation method for a defective homogeneous component is extended to a mismatched component, by incorporating the effect due to the strength mismatch between the weld metal and the base material. The key element is a mismatch limit load. For instance, the R6/R5 procedure employs an equivalent material concept, defined by a mismatch limit load. A premise is that if a proper mismatch limit load solution is available, the same concept can be used for any defect location (either a weld centre defect or a heat affected zone (HAZ) defect) and for any material combination (either two-material or multi-material combinations; either similar or dissimilar joints). However, validation is still limited, and thus a more systematic investigation is needed to generalise the suggestion to any geometry, any defect location and any material combination. This paper describes the effect of structural geometry on the $C^*$ integral for defective similar welds, based on systematic elastic-creep 2-D and 3-D finite element (FE) analyses, to attempt to elucidate the questions given above. It is found that the existing 'equivalent material' concept is valid only for limited cases, although it provides conservative estimates of $C^*$ for most of cases. A modification to the existing equivalent material concept is suggested to improve accuracy.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.940-946
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• 2015

In this paper, we study a method that amplifies the output gain of a high voltage pulse using 300 kHz or higher frequency. We conducted a study on a method for amplifying the output gain using the resonance between the capacitance components of the load and the parasitic components of the circuit, instead of the conservative method for amplifying the pulse-amplitude by raising the voltage of the power stage. In particular, the method simplifies the circuit configuration throughout the appliance of flyback-type topology instead of the bridge-type. There are advantages that prevent damage from overload and the heat in the output circuit through the hard switching by amplifying the gain of the output voltage applying to the load as given by the capacitance component of the output electrode to the output pulse waveform. This study proposed a method to enhance the spatial and electrical efficiency of the contact-type heating device through the dielectric heating method applied to the field of medical and industrial heating.

• Fire Science and Engineering
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• v.30 no.5
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• pp.116-123
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• 2016

The quantitative risk assessment methods for thermal failure in targets were studied using fire modeling. To this end, Fire Dynamics Simulator (FDS), as a representative fire model, was used and the probabilities related to thermal damage to an electrical cable were evaluated according to the change in fire area inside a specific compartment. 'The maximum probability of exceeding the damage thresholds' adopted in a conservative point of view and 'the probability of failure' including the time to damage were compared. The probability of failure suggested in the present study could evaluate the quantitative fire risk more realistically, compared to the maximum probability of exceeding the damage thresholds with the assumption that thermal damage occurred the instant the target reached its minimum failure criteria in terms of the surface temperature and heat flux.

• Nuclear Engineering and Technology
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• v.14 no.3
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• pp.122-137
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• 1982

Analyzed is the sensitivity of reactor transient behavior to various reactor parameters during the reactivity induced accidents (RIA) of the Kori Unit 1. Included in the analysis is a partial spectrum of RIAs with relatively fast transients such as uncontrolled rod cluster control assembly bank withdrawl from a subcritical or low power startup condition and rod ejection accidents. The analysis can be performed generally in three steps: calculation of an average core power change, hot spot heat transfer calculation and DNBR (departure from nucleate boiling ratio) calculation. The computer codes used for the analysis are either developed based on the codes relevent to it. These codes are evaluated to be highly reliable. An extensive sensitivity analysis is performed to study the effects of various reactor design and operating parameters on the reactor transient behavior during the accidents. The assumptions and initial conditions used for the RIA analysis in the Kori Unit 1 FSAR (Final Safety Analysis Report) are reexamined, and the corresponding analysis results are reassessed, based on the sensitivity analysis results, to be conservative and reliable.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.392-403
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• 1997

There is a strong international move towards performance based fire regulations for buildings with New Zealand and Australia at the forefront of research in this fold. The reform of regulations is thought to offer more innovation and flexibility in building design and greater cost effectiveness in construction. An important part of the research in this area is related to the development of agreed approaches to fire safety design, such as the Fire Code Reform Centre's "Fire Engineering Guidelines" or New Zealand's "Fire Engineering Design Guide". Such design process documents have incorporated or referenced much of the latest research in areas such as: tenability criteria fire compartment models egress models risk assessment. Use of such design guidelines or equivalents in major projects in countries such as Hong Kong and Australia have highlighted where fro engineering can offer real benefits to building designers and ultimately building owners and operators. However, there is still much research to be done and use of a systematic, logical design approach clearly identifies where design data or modelling techniques are still urgently required. Such areas are: fire growth rates and peak heat release rates for non-residential occupancies pre-movement times related to egress experimental validation and limits of applicability of CFD and other compartment Ire models probability/reliability data on fire protection systems for risk based analysis. Examples from case studies will be shown where lack of such research and poor judgement can lead to inferior design solutions or where unnecessarily conservative designs can lead to cost excesses. In summary, the link between Ire engineering designers and the research community is very important to highlight areas of fire research that will have the most benefit to the building and construction industry.nstruction industry.

• Restorative Dentistry and Endodontics
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• v.5 no.1
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• pp.29-34
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• 1979

The purpose of this study was to measure thermal expansions of dental investments, Biovest(Casting Investment. Dentsply International INC, U.S.A.), Multi-Best (Use for all dental chrome-cobalt alloys, The Ransom & Randolph Co. U.S.A.), Kerr(Inlay Investment. Sybron Kerr, U.S.A.), O. K. (Inlay Investment. Shofu Dental MFG, Co. Japan), Whip-Mix (Cristobalite Inlay Investment. Whip-Mix Corporation. U.S.A.). Thermal expansion of specimens(5mm in diameter and 50mm in length) was measured by a dilatometer at the temperature range from $20^{\circ}C$ to $700^{\circ}C$ by comparing expansion between standardized quartz and experimental specimens with heating rate about $300^{\circ}C$/hr. The following results were obtained. 1. The coefficient of thermal expansion of Biovest was $15{\times}10^{-6}/^{\circ}C$ in the water powder ratio 18/100 and $14{\times}10^{-6}/^{\circ}C$ in the water powder ratio 28/100. Those of Multi-Best were $9{\times}10^{-6}/^{\circ}C$ in the water powder ratio 14/100 and $7{\times}10^{-6}/^{\circ}C$ in the water powder ratio 24/100. 2. The coefficient of thermal expansion of Kerr were $17{\times}10^{-6}/^{\circ}C$ in the water powder ratio 38/100 and $14{\times}10^{-6}/^{\circ}c$ in the water powder ratio 48/100. Those of O. K. were $9{\times}10^{-6}/^{\circ}C$ in the water powder ratio 33/100 and $7{\times}10^{-6}/^{\circ}C$ in the water powder ratio 43/100 3. The coefficient of thermal expansion of Whip-Mix were $14{\times}10^{-6}/^{\circ}C$ in the water powder ritio 40/100 and $12{\times}10^{-6}/^{\circ}c$ Fein the water powder ratio 50/100. Those of Hi-Heat were $11{\times}10^{-6}/^{\circ}c$ in the water powder ratio 28/100 and $10{\times}10^{-6}/^{\circ}c$ in the water powder ratio 38/100.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.4
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• pp.191-202
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• 2020

Purpose : The purpose of this study is to examine the effect of the segmental mobilization technique of the lower back on the characteristics of the muscles and limited of stability of chronic backache patients. Methods : The subjects of the study were 30 chronic back pain patients who were divided into groups of 15, a manual therapy group (Group I) and a spinal decompression therapy group (Group II), via random assignation. The subjects had 15 minutes of superficial heat therapy, 15 minutes of interference wave therapy, and 5 minutes of ultrasound therapy for conservative physical therapy. Additionally, manual therapy and spinal decompression therapy were administered to each group for 30 minutes, 5 times a week for 8 weeks. Before intervention, the characteristics of the muscles and limited of stability of the muscles were analyzed. After 8 weeks of intervention, the above items were re-measured in the same manner and analyzed between groups. Results : The results of comparative analysis of the characteristics of the muscles and limited of stability between groups showed that there were statistically significant differences. The manual therapy group (Group I) showed significant differences in characteristics of the muscles compared to the spinal decompression therapy group (Group II). The manual therapy group (Group I) showed significant differences in limited of stability compared to the spinal decompression therapy group (Group II). Conclusion : The result confirmed that manual therapy was more effective in the characteristics of the muscles and limited of stability. Based on this study, additional studies are necessary on the effect of various techniques of manual therapy on muscle activity and muscle thickness in chronic back pain patients. In order to develop an effective manual therapy program, studies using a variety of evaluations are needed.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.85-99
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• 2024

As the proliferation of hydrogen electric vehicles accelerates, there is observed diversification in hydrogen refueling station models. This diversification raises safety concerns for different types of stations. This study conducted a quantitative risk assessment of a multi-vehicle hydrogen station, capable of simultaneously refueling cars, buses, and trucks. Utilizing Gexcon's Effects&Riskcurves Software, scenarios of fire and explosion due to hydrogen leaks were assessed. The study calculated the impact distances from radiative heat and explosion overpressure, and measured risks to nearby buildings and populations. The largest impact distance was from fires and explosions at dispensers and high-pressure storage units. High-pressure storage contributes most significantly to personal and societal risk. The study suggests that conservative safety distances and proper protective measures for these facilities can minimize human and material damage in the event of a hydrogen leak.

• Journal of Haehwa Medicine
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• v.15 no.1
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• pp.125-140
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• 2006

Study of east & west medical science documentary records of Hip joint pain lead to following conclusions. 1. Easten medicine classify hip joint pain with terms "Bi-chu-tong", "Bi chu in tong" "Bi-chu-choong-tong". 2. Easten medicine asorts cause of hip joint pain with external factor, such as exogenous energy, six yin evil energy and intrinsic factor, which are weakness caused by prolonged deasease, warm-heat evil. 3. In western medicine, causes that trigger hip joint pain are trauma, fracture, dislocation,and bacterial infection. 4. Treatment of hip joint disorder in western medicine, physiotherapy concerning conservative treatment, and pain control with drug treatment, kinesitherapy are used, and concernig fracture, operation is used. 5. In Eastern medicine, principle of treating hip joint pain, sung-juk-sa-ji(盛則寫之), hu-juk-bo-ji(虛則補之), yul-juk-jil-ji(熱則疾之), han-juk-yu-ji(寒則留之), ham-ha-juk-chim-ji(陷下則沈之), bul-sung-bul-hu(不盛不虛), yi-kyong-chui-ji(以經取之) is presented. This priciple of treatment was descended through ages and is now applied to treatments such as Acupuncture, Herbal, physical treatment based on so-san-eo-hyul(消散瘀血), seo-kun-tong-rak(舒筋通絡), so-ri-kwan-jul(疏利關節) principle. 6. In Eastern medicine, meridians used to treat hip joint pain are The Chok yangmyung wi Kyong(足陽明胃經), Chok taeum bi Kyong(足太陰脾經), Chock soyang dam Kyong(足少陽膽經), Chock guelum gan Kyong(足厥陰肝經). In conclusion, hip joint pain should be considered in relationship with internal organs and whole body system. Western & Eastern point of view should be carefully inspected and connected and intensive study of nervous system and meridian is required, in order to adopt best treatment for the patients.