• Nuclear Engineering and Technology
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• v.52 no.9
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• pp.2100-2106
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• 2020

This paper newly proposes an efficient analytic springback prediction method to predict the final dimensions of bent cylindrical tubes for a helical tube steam generator in a small modular reactor. Three-dimensional bending procedure is treated as a two-dimensional in-plane bending procedure by integrating the Euler beam theory. To enhance the accuracy of the springback prediction, mathematical representations of flow stress and elastic modulus for unloading are systematically integrated into the analytic prediction model. This technique not only precisely predicts the final dimensions of the bent helical tube after a springback, but also effectively predicts the various target radii. Numerical validations were performed for five different radii of helical tube bending by comparing the final radius after a springback.

• Structural Engineering and Mechanics
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• v.58 no.4
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• pp.641-659
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• 2016

This paper deals with the pure bending of incompressible elastic perfectly plastic two-layer sheets under plane strain conditions at large strains. Each layer is classified by its yield stress, shear modulus of elasticity and its initial percentage thickness in relation to the whole sheet. The solution found is semi-analytic. In particular, a numerical technique is only necessary to solve transcendental equations. The general solution is cumbersome because different analytic expressions for the radial and circumferential stresses should be adopted in different regions of the whole sheet. In particular, there are several alternative ways a plastic region (or plastic regions) can propagate. However, for any given set of material and process parameters the solution to the problem consists of a sequence of rather simple analytic expressions connected by transcendental equations. The general solution is illustrated by a simple example.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.732-737
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• 2006

The facility diagnosis technique of past subjective judged the technical expert and interpreted stably mainly. The facility the periodical civil official becomes indispensability consequently with the law and the system and objectivity inspection which relates with a this and development of diagnosis technique were necessary. Currently the evaluation elements which relate with an inspection and diagnosis technique depended to the subjectivity of each facility quality, data statistics, diagnosis know-how, various circumstance and the technical expert and the evaluation item came to decide. But the evaluation score distribution of marks of each item depended plentifully in data analysis result and experience. The past method is weak in logically because the objection theoretical background and basis are insufficiency. Consequently in order to apply a data analysis result and an experience logically, it used AHP(Analytic Hierarchy Process) method from this research. It is visible with the fact that the application result reconfirmation and complement process will be necessary the technique which is suitable in the multi facility management. Also it is expected with the fact that the application characteristic from the next relation technique will be excellent.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.390-394
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• 1999

In this paper, we have evaluated BER performance of digital subscriber line(DSL) using the twisted-pair channel model by means of Semi-analytic simulation technique. As a result, it was known that the Semi-analytic simulation was proved to be a good technique because of the attenuation of 0.5dB. To keep the BER=10$\^$-7/, 4dB of E$\^$b//N$\^$0/ is needed more when the DSL length extends to 5000m, while 2dB increase of E$\^$b//N$\^$0/ is required when Nyquist frequency goes to 512kb/s with the keeping same distance. In addition, the effect by FEXT noise is serious, when the FEXT noise damping constant, k is over 10/sup-10/ in DSL length and 10$\^$-14/ in the aspect of Nyquist frequency. As the basic, results of this analysis can be used in setting in internal and external standardization of DSL system in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2C
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• pp.247-254
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• 2004

We introduce a new space-time signal processing scheme that uses both transmitter diversity technique and transmitter beamforming technique for code-division multiple access (CDMA) systems. Over complex Gaussian Rayleigh channel, the introduced scheme achieves the diveristy gain through the transmitter diversity technique. and the SNR gain by th transmitter beamforming technique. Bit error rate (BER) analyses are given to each of the three cases in which the transmitter diversity scheme, the transmitter beamforming scheme and the introduced scheme are used, in the slowly varying Rayleigh frequency nonselective fading channel. The Monte-Carlo simulation results are shown to match to the analytic results. When the channels between distant antennas are independent, analytic results show that the introduced scheme achieves the lowest $E_{b/}$ $N_{0}$ at target BER 10$^{-6}$ . When the channels between distant antennas are correlated, analytic and simulation results show that the introduced scheme is more robust to the change of channel correlation.n.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.112-121
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• 2011

It has become general common sense through numerous researches that exercise provides positive impacts on physical and mental health. And it has been reported that regular exercise adjusts obesity by reducing body fat and lipid levels found in the blood and ultimately, it improves human quality of life. In this study, indices for managing swimming exercise therapy were induced through prior researches and weighted value was measured by modelling correlations between indices by using fuzzy ANP (Analytic Network Process) technique. With the determined results, users can be provided with real-time individualized exercise prescription without space constraint. And patient management system was intended to be realized so that tailor-made management per patient can be established on real-time through mobile equipments such as portable phone, smart phone, notebook and etc.

• Journal of the Korea Institute of Building Construction
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• v.10 no.4
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• pp.95-103
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• 2010

The purpose of this study is to propose a decision-making technique for selecting waterproofing methods using the Analytic Hierarchy Process (AHP) technique. In this study, a questionnaire survey was given to a group of specialists, which included design specialists, construction specialists, and maintenance specialists, regarding their experience with roof waterproofing methods. The 1st level hierarchy of the questionnaire survey addressed the function, economics, and maintenance of each of the roof waterproofing methods. The rank of 13 items of questionnaire, which is the 2nd level hierarchy of the questionnaire survey, is calculated using Expert Choice Solution. The analysis of questionnaire survey shows that each specialist selects different roof waterproofing methods, and all specialists make much of waterproof performance.

• Korean Management Science Review
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• v.11 no.3
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• pp.129-151
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• 1994

This paper focuses on method of setting priorities for telecommunications Standardization in which usually includes prioritization, resource allocation, standardization schedule for each SWA is based on prioritization of SWAs. We mainly used the Analytic Hierarchy Process(AHP) and a modified Delphi technique as a method for planning process. Recently, rapid technology evolution in telecommunications fields increases the necessity of developing more and more new standards. Also increased complexity of technologies makes standards more complicated, more specified and more thick than the past ones. As a result, the number of SWAa(Standardization Work Areas) and SWIs(Standardization Work Iterms) is being increased continuously. Furthermore, rapid telecommunication environment changes such as deregulation, liberalization, privatization, regionalization, and globalization surrounding telecommunications standardization grows increasingly important. To cope with these challenges and to make the more efficient use of the limited standardization resources, i.e., time, financial, personal resources, we will suggest logical and rational approach that is a backbone of strategic plan for telecommunication standardization. The telecommunication standardization planning process involves a MCDM(Multi-Criteria Decision Making) process. The Analytic Hierarchy Process(AHP) is a kind of MCDM approach. Our method is based on a combination of a modified Delphi technique and an application of AHP(spreadsheet model). Analyzed data from Delphi technique is used as inputs to AHP. In addition we also focus on the technique how to combine group judgments and to handle a large number of comparisons.

• The Journal of Korea CHUNA Manual Medicine
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• v.1 no.1
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• pp.55-65
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• 2000

The present study retrospectively investigated clinical outcome at patients with low back pain or sciatica during Chuna treatment (flexion-distraction technique). The study population consisted of 29 patients. Discogenic group consisted of 21 patients who were already diagnosed as HNP of lumbar spine with serial MRIs(magnetic resonance imaging) or CTs(computerized tomography). Simple LBP group consisted of 8 patients with low back pain & sciatica who were non-specific disorder on radiologic examination. All patients were treated with flexion-distraction technique, one of Chuna technique, under analysis of Moire Topography. And the evaluation of clinical outcome was done twice during this study by Moire Topography Analytic Point and Low Back Pain Assesment, Visual Analogue Scale. The results were summarized as follows; Total improvement rate of Moire Topography was $25.8{\pm}17.8%$, and the rate of Low Back Pain Assesment was $56.5{\pm}23.0%$, Visual Analogue Scale of post-treatment was $32.6{\pm}22.5$ Between Improvement rate of Moire Topography and improvement rate of Low Back Pain Assesment, significant correlation was proved(Person's coefficient was 0.381, p<0.05). After all, it is certain improvement of Moire Topography represents symptom's improvement.

• Bulletin of the Korean Mathematical Society
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• v.55 no.3
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• pp.749-762
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• 2018

In this paper, the new optimal perturbation iteration method has been applied to solve the generalized regularized long wave equation. Comparing the new analytic approximate solutions with the known exact solutions reveals that the proposed technique is extremely accurate and effective in solving nonlinear wave equations. We also show that,unlike many other methods in literature, this method converges rapidly to exact solutions at lower order of approximations.