• 한국전산유체공학회:학술대회논문집
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• 1999.11a
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• pp.77-84
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• 1999

Numerical design optimization techniques are implemented for the improvement of the ram accelerator performance. The design object is to find the minimum ram tube length required to accelerate projectile from initial velocity $V_0$ to target velocity $V_e$. The premixture is composed of $H_2,\;O_2,\;N_2$ and the mole numbers of these species are selected as design variables. The objective function and the constraints are linearized during the optimization process and gradient-based Simplex method and SLP(Sequential Linear Programming) have been employed. With the assumption of two dimensional inviscid flow for internal flow field, the analyses of the nonequilibrium chemical reactions for 8 steps 7 species lave been performed. To determined the tube length, ram tube internal flow field is assumed to be in a quasi-steady state and the flow velocity is divided into several subregions with equal interval. Hence the thrust coefficients and accelerations for corresponding subregions are obtained and integrated for the whole velocity region. With the proposed design optimization techniques, the total ram tube length had been reduced $19\%$ within 7 design iterations. This optimization procedure can be directly applied to the multi-stage, multi-premixture ram accelerator design optimization problems.

• The Journal of Internal Korean Medicine
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• v.26 no.4
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• pp.881-888
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• 2005

Pontine infarction presents variable neurologic deficits because the pons is a very complicated organ with cranial nerve nuclei and several fiber tracts. A 65 year-old women with dizzness, ataxia and diplopia because of Pontine infarction was admitted at Wonkwang University Jeonju Oriental Medicine Hospital. She was treated with the herbal medicine Joganiknoe-tang(助肝益腦湯) and with acupunture. Improvement in these symptoms was observed, so the specifics of the process in which the patient was treated are here described. Results suggest that Joganiknoe-tang(助肝益腦湯) is an effective treatment for symptoms of pontine infarction.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.21-21
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• 2003

To increase the light-emission efficiency of LED, we increased the internal and external quantum efficiency by suppressing the defect formation in the quantum well and by increasing the light extraction efficiency in LED, respectively. First, the internal quantum efficiency was improved by investigating the effect of a low temperature (LT) grown p-GaN layer on the In$\sub$0.25/GaN/GaN MQW in green LED. The properties of p-GaN was optimized at a low growth temperature of 900oC. A green LED using the optimized LT p-type GaN clearly showed the elimination of blue-shift which is originated by the MQW damage due to the high temperature growth process. This result was attributed to the suppression of indium inter-diffusion in MQW layer as evidenced by XRD and HR-TEM analysis. Secondly, we improved the light-extraction efficiency of LED. In spite of high internal quantum efficiency of GaN-based LED, the external quantum efficiency is still low due to the total internal reflection of the light at the semiconductor-air interface. To improve the probability of escaping the photons outside from the LED structure, we fabricated nano-sized cavities on a p-GaN surface utilizing Pt self-assembled metal clusters as an etch mask. Electroluminescence measurement showed that the relative optical output power was increased up to 80% compared to that of LED without nano-sized cavities. I-V measurement also showed that the electrical performance was improved. The enhanced LED performance was attributed to the enhancement of light escaping probability and the decrease of resistance due to the increase in contact area.

• Journal of Haehwa Medicine
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• v.16 no.2
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• pp.229-234
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• 2007

Objectives : Chronic renal failure(CRF) is a pathophysiologic process with multiple etiologies, resulting in the inexorable attrition of nephron number and function and frequently leading to end-stage renal disease. It causes various symptoms(edema, general body weakness, nausea, anorexia, uremia, osteodystrophy and so on) which impair quality of life and long term complications. The purpose of this case is to report the improvement of a patient with chronic renal failure. Methods : We treated the patient with herbal medication(Gyulpyjeonwon) and measured the creatinine, BUN, albumin, hemoglobin in the serum. Results : Gyulpyjeonwon decreased serum creatinine and BUN level and increased serum albumin and hemoglobin level. And the symptoms of CRF(edema, general body weakness, anorexia) was improved significantly. Conclusions : This case suggests the efficacy of herbal medication(Gyulpyjeonwon) to patient who was involved CRF.

• Nuclear Engineering and Technology
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• v.25 no.4
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• pp.570-587
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• 1993

Recently a number of severe fuel degradation events, seemingly due to internal secondary hydriding, have been reported. This paper reviews internal hydriding of defected zircaloy cladding. First, the history of zircaloy cladding development and the environment of the zircaloys in service in the nuclear reactor are introduced. Fundamental aspects of zircaloy hydriding, such as hydrogen permeability in zirconium oxide, terminal solubility and precipitation in zirconium and its alloys, and the deleterious effect of hydrides are reviewed. The mechanism of massive internal hydriding in defected zircaloy fuel rods is qualitatively described based on the observed phenomena. Significant factors affecting the hydriding process are discussed. A quantitative model for the massive hydriding as a part of an effort to mitigate fuel degradation is briefly mentioned and necessary information and recommended future work for improvement of the model are outlined.

• The Journal of Information Systems
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• v.18 no.3
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• pp.299-326
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• 2009

R In today's competitive and global business management, Concern of an enterprise is to strengthen the core competency and improve it's internal business process. Therefore, Interest in BPM(Business Process Management) has grown rapidly. BPM is recognized as best solution to meet the needs of organizations that seek the cost down, integration of information, reducing of risk, improvement of productivity. In the past, the company have usually made huge investments in knowledge management systems which are based on repository keeping tacit knowledge. But this paper shows feasibility of implementation of business process-based knowledge management system that could link knowledge with business process. From an academic point of view, Although There could be several ways to build the business process-based KMS. In this paper, when BPM project and KMS project were started at the same time, the way of how to provide workers with task-related knowledge was discussed. As an case study, an estimate process of H company was analyzed and process modelling was carried out and conceptional architecture framework was depicted.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.170.5-170
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• 2001

As close competitions are being fought out among enterprises, they should accomplish their objectives such as reduction of cost, improvement of quality and condensation of due date, etc. For this objects, it becomes very important to manage the workflow harmoniously and to share the information efficiently between geographically dispersed users. We developed the collaborative design system, which manages various design process and enables to share design information. In this paper, Internal-based collaboration system for press die design process in the automobile manufacturer is developed with CORBA, Java and relational database system. After modeling real press die design process with UML language, workflow routing path is created by modeling data. Cost and time for ...

• Journal of Aerospace System Engineering
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• v.1 no.1
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• pp.60-66
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• 2007

The importance of software development in the integration of an avionics system is continuously increasing. And we can expect enlarged soft ware portion in the system integration for the more intelligent, reliable, and automated avionics system. For an avionics system software development the selection of a real-time operating system and internal avionics data bus protocol is very important from the viewpoint of the integration with the system hardware. In this paper, we present current trend of an avionics system software development including software development methodology, software development process, and international software process assessment improvement model.

• Journal of the Korean Society of Safety
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• v.10 no.3
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• pp.11-20
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• 1995

In recent years, the study on the high efficiency of the internal combustion engine has been mainly proceeding. In this study, we developed rotary valve to achieve the improvement of volumetric efficiency and to be simple construction. And then made a comparative analysis between rotary and poppet valve. In this experiment, rotary valve enlarged the flow area of valve port to minimize the resistance of the fluid flow and to flow smoothly in intake and exhaust process. Indeed, valve timing was controlled properly lest positive pressure in exhaust process should affect intake process. Motoring and firing experiments were using engine speed and air-fuel ratio as the principle parameter and the full opening of throttle valve and minimum spark advance for best torque (MBT) as engine operating variables.

• Quality Improvement in Health Care
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• v.7 no.2
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• pp.180-188
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• 2000

Objectives : The purpose of this study was to evaluate the reliability of questionnaire according to item arrangement on patient satisfaction questionnaire. Methods : We developed the two types of questionnaire with different item arrangement. In the first type (A), questions were arranged according to medical service dimensions. Questions in the second type (B) were arranged according to medical process. Both questionnaires were composed of six dimensions: physical environments, process, competence, courtesy, information giving, understanding patients. Measurements were performed on a 5-score Likert scale. In an outpatients and inpatient survey, total 777 patients answered the type A (outpatients: 257, inpatients: 128) or Type B (outpatients: 257, inpatients: 135). In order to compare the internal consistency of two types. Cronbach's ${\alpha}$ were calculated. Multiple regression analysis was also performed to know which type of questionnaire explain more of the overall satisfaction. Results : In outpatient survey, type A questionnaire showed higher internal consistency than B except physical environments dimension. Also in inpatient survey, type A had higer internal consistency than B in four dimensions(process, competence, courtesy, understanding patients). In the results of multiple regression analysis, type A questionnaire ($R^2$=0.53) explained more of the variation in overall satisfaction then B questionnaire ($R^2$=0.43) in outpatient survey. In inpatient survey, type B questionnaire ($R^2$=0.40) explained, more of the variation in overall satisfaction than type A questionnaire ($R^2$=0.33).But the difference of R was not significant in inpatient survey. Conclusion : The results of this study support that type A questionnaire has higer reliability in assessment of consumer satisfaction than type B.