• Journal of applied mathematics & informatics
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• v.40 no.1_2
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• pp.25-45
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• 2022

In this study, the non-standard finite difference method for the numerical solution of singularly perturbed parabolic reaction-diffusion subject to Robin boundary conditions has presented. To discretize temporal and spatial variables, we use the implicit Euler and non-standard finite difference method on a uniform mesh, respectively. We proved that the proposed scheme shows uniform convergence in time with first-order and in space with second-order irrespective of the perturbation parameter. We compute three numerical examples to confirm the theoretical findings.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.4
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• pp.681-693
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• 1995

A new set of capillary tube selection charts for R-22 is proposed. The set of charts takes into account of the roughness effect on the mass flow rate. For this purpose, a set of numerical model is developed and a series of experiments is conducted to verify the numerical model. A numerical model is used to calculated the mass flow rate for several sets of tube diameter, length, inlet pressures and degree of subcooling. The outlet of the tube is controlled to be at critical condition. The experimental flow rate is compared with calculated values. The calculated values are consistently less than the experimental ones except for the flow rate range below 40kg/hr. The deviation is within 10---. Based on the nunmerical model and results of experiments, the set of capillary tube selection charts for R-22 is constructed. The set of charts consists of standard capillary tube chart(L=2030mm, d=1.63mm, ${\varepsilon}=2.5{\mu}m$), non -standard flow factor(${\phi}_1$) chart, and non-standard roughness factor(${\phi}_2$) chart. The mass flow rate, flow factor, and the roughness factor are defined respectively as; $\dot{m}={\phi}_1{\phi}_2\dot{m}_{standard}\\{\phi}_1=\frac{\dot{m}(L,\;d,\;\varepsilon_{standard})}{\dot{m}_{standard}(L_{standard},\;d_{standard},\;{\varepsilon}_{standard})}\\{\phi}_2=\frac{\dot{m}(L_{standard},\;d_{standard},\;{\varepsilon})}{\dot{m}_{standard}(L_{standard},\;d_{standard},\;{\varepsilon}_{standard})}$.

• Korean Journal of Acupuncture
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• v.28 no.3
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• pp.177-186
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• 2011

Objectives : The aim of this study is to review clinical trials using Qigong exercise on patients with hypertension and to assess their methodology and results. Methods : Electronic literature searches for clinical trials (randomized trial, non-randomized trial, before-after study) of Qigong exercise were performed in 21 electronic databases (5 international databases and 16 Korean databases). English, Korean or Chinese articles were included. Laboratory or animal studies were excluded. Results : A total of 11 studies met the inclusion criteria. Five randomized controlled trials, Four non-randomized trials and two before-after studies were included. Seven studies used self-developed Qigong exercise. Two studies used Guolin Qigong exercise and two studies used Qigong exercise with an anti-hypertension drug. Of the nine randomized trials or non-randomized trials, four studies used an anti-hypertension drug control and three studies used waiting list controls. Compared to baseline, a change in blood pressure after the Qigong exercise treatment was significant in all studies. However, the results effect of blood pressure between Qigong exercise and controlled trials were not consistent. Conclusions : There are low-quality clinical trials of Qigong exercise for hypertension. To evaluate the effects of Qigong exercise, more rigorous trials are warranted.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.692-697
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• 1994

In the actual sound environmental systems, it seems to be essentially difficult to exactly evaluate a whole probability distribution form of its response fluctuation, owing to various types of natural, social and human factors. Up to now, we very often reported two kinds of unified probability density expressions in the standard expansion from of Hermite and Laguerre type orthonormal series to generally evaluate non-Gaussian, non-linear correlation and/or non-stationary properties of the fluctuation phenomenon. However, in the real sound environment, there still remain many actual problems on the necessity of improving the above two standard type probability expressions for practical use. In this paper, first, a central point is focused on how to find a new probabilistic theory of practically evaluating the variety and complexity of the actual random fluctuations, especially through introducing some equivalence transformation toward two standard probability density expressions mentioned above in the expansion from of Hermite and Laguerre type orthonormal series. Then, the effectiveness of the proposed theory has been confirmed experimentally too by applying it to the actual problems on the response probability evaluation of various sound insulation systems in an acoustic room.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2002.11a
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• pp.307-313
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• 2002

Urban style row-rise houses for rent have been supplied to the center of city from the 1950's first half The amount of stock is about 450,000 houses and occupies about 40％ in the private rented house. As for the structure, the 60％ of them is wooden-structure and the rest is non-wooden. Stocks of 57.5％ of the wooden-structure and 86％ of the non-wooden were built after 1981 years. It was 1981 years that the new earthquake-resistant standard was carried out, the improvement of stocks built before 1981 is necessary because those don't satisfy the present standard. To investigate the renovation possibility of urban style row-rise houses for rent, actual situation of two-story apartment at 2,4, and 5 Chome Taito-Ku in Tokyo was surveyed from July to November 2001. The number of building analyzed is 227 ridges among 234 ridges of the surveyed two-story building. 90％ of building analyzed is wooden structure. 1) The site of 88％ building surveyed is close to a road less than 4m width. It becomes the existing non-conformed building in the building construction act. It is impossible to make a renovation such as rebuilding, extension and remodeling because it requires the set back when renovating this type of non-conformed building, 2) The building built before 1981 is almost wooden-structure, and occupies 37％ of the building surveyed, and doesn't satisfy the present earthquake-resistant standard. An improvement of them is needed because the decrepitude of building proceeds. 3) 50％ of openings and 40％ of windows of the building surveyed doesn't use noncombustible materials. Though it becomes the existing non-conformed building, it can satisfy the present standard by replacing openings with noncombustible materials.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.926-932
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• 2007

A recently developed methods for on-site calibration of the current transformer (CT) comparator system have been reviewed in the paper. The method utilizes several traveling standards, which consist of the CT, non-reactive standard resistors, wide ratio error CT, and shunt resistors. The traveling CT is used for absolute evaluation of a standard CT belonging to industry. The non-reactive standard resistors and a wide ratio error CT are used for the linearity check of errors in the current comparator. The shunt resistors are used for evaluation of CT burden of industry.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1268-1274
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• 2007

A recently developed methods for the on-site calibration of the voltage transformer (VT) comparator system have been reviewed in the paper. The method utilizes the several traveling standards consisting of the VT, the non-reactive standard resistors, the wide ratio error VT, and the decade resistors. The VT is used for the absolute evaluation of a standard VT belonging to the industry. The non-reactive standard resistor and wide ratio error VT are used for the linearity check of errors in the voltage comparator of the industry. The decade resistors are used for evaluation of a VT burden of the industry.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.173-178
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• 2002

Traditionally, for space program whose operation environment is severe, high reliability parts, that is class s microcircuit, JANS level semiconductor, and ER passive parts, are reliable choices. But in some case, we must use 'Non-standard Part' which is not verified as high reliability standard part. To use 'Non-standard Part' in space application, the manufacturer should qualify the part and screen potential week part from the flight lot. In this technical memo, I introduce the flight part verification process for KOMPSAT 1 and KOMPSAT 2 program.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.2
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• pp.18-24
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• 2010

On-board spectrophotometer has been widely used as a non-contact and non-destructive measurement system in many fields. In this study, we evaluated the effect with respect to the light of on-board spectrophotometer based on a comparison with the standard spectrophotometer and color information coordinate system. Red, yellow, green and blue color paper, which were the standard reflective color paper and Munsell color paper, were used for experiments. In order to compare between a standard spectrophotometer system and an on-board spectrophotometer system, each color paper was measured 20 times. We concluded that it is possible to develop a system regardless the effect of light if the light was supplied consistently and a calibration was performed exactly while we applied an on-board spectrophotometer to non-contact and non-destructive measurement system.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.32
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• pp.29-56
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• 2006

This article primarily concerns the various aspects of the rules to control express terms particularly in standard form which seek to absolve either wholly or in part from the seller's liability for non-conforming goods. It describes and analyzes in detail how English law regulates such terms. In this analysis, it places the following questions; first, whether each jurisdiction treats the seller's liability for non-conformity in quality and quantity as mandatory rules, second, if it does, to what extent it is treated so and third, if not, in what way it controls the seller's attempt to exclude or restrict his liability for non-conformity in quality and quantity. In addition, it attempts to compare the rules under English law with those under Korean law and to evaluate them in light of the discipline of comparative law. In an attempt to evaluate them, it asks the question of whether a solution from one jurisdiction may facilitate the systematic development and reform of another jurisdiction. The evaluation is based upon the idea that the problems of fairness associated with the use of standard terms occur where the customer is unfairly taken by surprise due to his ignorance of the terms, or where even if he knows of the substance of the terms and objects to it, he is met with a take-it-or-leave-it situation.