• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.662-670
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• 2019

Tanker cargo tanks are equipped with the means of raising and maintaining the cargo discharge temperature to a suitable level. In this paper, a new heating coil design is proposed and analyzed. Contrary to conventional designs, wherein the heating coils are evenly distributed over the tank bottom, the proposed design arranges the heating coils in the central part of the tank bottom, in a vertical direction. Due to the intensive cargo circulation generated, a forced convection is superimposed on a buoyancy-driven natural convection, providing a more efficient mixed convection heat transfer mechanism. Numerical simulations performed by using a finite volume method show that in the case of 7-bar steam Bunker C heavy fuel oil heating, a five-hour circulation phase average heat transfer coefficient equals 199.2 W/m²K. This result might be taken as an impetus for the more thorough experimental examination.

• Journal of the Korea Society of Computer and Information
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• v.4 no.4
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• pp.193-198
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• 1999

According to the spread of Asynchronous Tranfer Mode(ATM) Networks Telecommunication Management Network(TMN) over ATM Networks becomes an important issue. This paper presents with an Performance Analysis and the designs for comparing TCP/IP-Based Internet SNMP(Simple Network Management Protocol) and ITU-T's Distributed CMIP configuration. The experimental results shows that propose method is expected to be effectively used in Distributed Environments such as Internet, ATM. and mobile networks where interoperability and scalability are required.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.417-420
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• 2009

The hot forming process of a CAM for vessel engine was designed by finite element (FE) simulation and experimental analysis. An aim of process design was to achieve the near-net shaped CAM forgings by hot forging process. Based on the compression test results of the low alloy steel, deformation processing map was generated using the superposition approach between the dynamic materials model (DMM) and flow stability and/or instability criteria. From the processing map, the initial heating temperature was determined as $1200^{\circ}C$. FE analysis was simulated to predict the formation of rolling defects and deformed shape with different forging designs. Optimum process design suggested in this work was made by comparing with the CAM for vessel engine manufactured by actual forging process.

• Solar Energy
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• v.7 no.2
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• pp.106-110
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• 1987

In the past few years, the subject of passive heating has been the major area of our concern due to the specific climate conditions prevailing in our region. More recently, however, other important issues such as retrofitting, passive cooling, optimized integration of conservation and passive solar, and daylighting have emerged as the areas of frequent discussions. KIER, the sole R&D organization in solar energy technologies, has accomplished significant results in passive building designs and actual demonstrations of experimental passive buildings. As a result of such endeavor by KIER, the passive solar buildings have been very well received by the Korean public. The current number of passive solar buildings in Korea is well over 1,600 (as of Dec. 1986). In this paper, broad aspects of the present status of passive solar technology utilization in Korea are presented.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.6
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• pp.269-277
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• 2005

In this paper, designs of an Interior Permanent Magnet Synchronous Motor (IPMSM) and its motor driver for 42V automotive air condition system are introduced. The characteristics of the IPMSM are predicted by using d-q equivalent circuit having the parameters, such as current phase angle, d-q axis inductances, core loss resistance, etc. The experimental and analysis results of the prototype are compared to show validity of the analysis method, and to give analyzed characteristics in detail. As the result, an improved IPMSM is designed to widen the operating speed limit of prototype; a cost effective AC drive are considered at the same time.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.3
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• pp.351-360
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• 1996

This study focuses on the development and evaluation of the high efficiency absorption chiller-heater, which can be applied to a direct gas fired, double effect system with 40RT (508,000kJ) cooling capacity. The performance of the absorption chiller-heater is investigated through cycle simulation and experiment to obtain the system characteristics with the inlet tenperature of cooling, chilled water, and gas input flow rate. The efficiency of the different cycles has been studied and the simulation and experiment results show that higher coefficient of performance could be obtained for mixed flow cycle. The five percent difference was obtained from the comparison between experimental and cycle simulation results. As a result of this study, the optimum designs were determined based on the operating conditions and the coefficient of performance.

• ETRI Journal
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• v.28 no.5
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• pp.607-614
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• 2006

This paper presents a new class of microstrip slow-wave open-loop resonator filters with reduced size and improved stopband characteristics. A comprehensive treatment of both ends loaded with triangular and rectangular ends is described, leading to the invention of a microstrip slow-wave open-loop resonator. Two-resonator and four-resonator bandpass filters are designed at the operating frequency of about 2 GHz, and a bandwidth of 60 MHz. The size of the slow-wave open-loop resonator is optimized from the standpoint of the unloaded Q-factor. The filters are not only compact in size due to the slow-wave effect, but also have a wider upper stopband resulting from the dispersion effect. The filter designs of this type are described in details. The experimental results are demonstrated and discussed.

• Journal of Ship and Ocean Technology
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• v.9 no.1
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• pp.64-71
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• 2005

In probabilistic design, the challenge is to estimate the uncertainty propagation, since outputs of subsystems at lower levels could constitute inputs of other systems or at higher levels of the multilevel systems. Three uncertainty propagation estimation techniques are compared in this paper in terms of numerical efficiency and accuracy: root sum square (linearization), distribution-based moment approximation, and Taguchi-based integration. When applied to reliability-based design optimization (RBDO) under uncertainty, it is investigated which type of applications each method is best suitable for. Two nonlinear analytical examples and one vehicle crashworthiness for side-impact simulation example are employed to investigate the unique features of the presented techniques for uncertainty propagation. This study aims at helping potential users to identify appropriate techniques for their applications in the multilevel design.

• Journal of Korean Biological Nursing Science
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• v.10 no.1
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• pp.33-40
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• 2008

Purpose: This study was performed to analyze the trend of foot reflexology research in nursing in Korea. Method: Of studies published in nursing literature between January 1990 and August 2007. The 74 articles were analyzed according to the published year and journal, type of research and study design, subject, and the outcome variables of interventions. Result: Prevailing research designs were experimental research (nonequivalent control group pretest-posttest design). Prevailing characteristics of subjects were patients with hypertension, diabetes mellitus, hemodialysis, cancer and others disease (osteoarthritis, cerebral vascular accident, pneumoconiosis). The most frequently performed intervention was Foot-Reflexo-Massage (FRM). The most frequently used outcome variables were fatigue and sleep. The effect of foot reflexology was inconclusive. Conclusion: The finding suggests that a robust research design in foot reflexology research is needed to accumulate a strong scientific evidence and to adopt nursing intervention from the foot reflexology modalities. Meta analysis of foot reflexology research should be done to analyze and integrate the results of various studies.

• Journal of the Korean Data and Information Science Society
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• v.10 no.1
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• pp.199-205
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• 1999

This paper discusses the generalized mixed-effects model for the analysis of overdispersed binomial data. Sometimes certain types of sampling designs or genetic characters of experimental units can be regarded as factors of extra binomial variation. For such cases, this paper suggests models with one or two random effects to explain overdispersion caused by those affecting factors and shows how to test for a model adequacy based on deviance.