• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.148-153
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• 1996

In this paper, an effective method for resolving difficulty resulting from the heterogeneity of the PWR baffle/reflector region is developed on the basis of the AFEN method. The essential difference of the new method from the conventional approach based on the equivalence theory is that the heterogeneous baffle/reflector is directly, without homogenization, considered as a node in nodal calculation Numerical results show that AFEN method with the new method can accurately predict both the multiplication factor and the power distribution of thermal reactors with baffle explicitly modeled.

• Computers and Concrete
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• v.28 no.6
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• pp.621-634
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• 2021

For the reliable strut-and-tie model (STM) design of disturbed regions of concrete members, structural designers must accurately determine the strength of concrete struts to check the strength conditions of a selected STM el and the anchorage of reinforcing bars in nodal zones. In this study, the author proposed a consistent numerical method for strut strength, applicable to all two-dimensional STMs. The proposed method includes the effects of a biaxial stress state associated with tensile strains in reinforcing bars crossing a strut, deviation angle between strut orientation and compressive principal stress flow, and degree of confinement provided by reinforcement. The author examined the method's validity through the STM prediction of the ultimate strengths of 517 reinforced concrete (RC) deep beams, 24 RC panels, and 258 RC corbels, all tested to failure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.531-539
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• 2017

The strut-tie model approach has been recognized as an efficient methodology for the design of all types of concrete members with D-regions, and the approach has been accepted in design codes globally. However, the design of concrete members with the approach requires many iterative numerical structural analyses, numerous graphical calculations, enormous times and efforts, and designer's subjective decisions in terms of the development of appropriate strut-tie model, determination of required areas of struts and ties, and verification of strength conditions of struts and nodal zones. In this study, a computer graphics program, that enables the design of concrete members efficiently and professionally by overcoming the forementioned limitations of the strut-tie model approach, is developed. In the computer graphics program, the numerical programs that are essential in the strut-tie model analysis and design of concrete members including finite element analysis programs for the plane truss and solid problems with all kinds of boundary conditions, a program for automatic determination of effective strengths of struts and nodal zones, and a program for graphical verification of developed strut-tie model's appropriateness by displaying various geometrical shapes of struts and nodal zones, are loaded. Great efficiency and convenience during the application of the strut-tie model approach may be provided by the various graphics environment-based functions of the proposed program.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6267-6272
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• 2015

Background: Extra nodal lymphoma (ENL) constitutes about 33 % of all non-Hodgkin's lymphoma. 18-28% develops in the head and neck region. A multimodality treatment with multi-agent chemotherapy (CT) and radiotherapy (RT) is considered optimum. Materials and Methods: We retrieved the treatment charts of patients of HNENL treated in our institute from 2001-2012. The charts were reviewed and the demographic, treatment details and outcome of HNENL patients were retrieved using predesigned pro-forma. Results: We retrieved data of 75consecutive patients HNENL. Median age was 47years (Range: 8-76 years). Of the 75 patients 51 were male and 24 were female. 55patients were evaluable. The patient and tumor characteristics are summarized in Table 1. All patients were staged comprehensively with contrast enhanced computed tomography of head, neck, thorax, abdomen, pelvis and bone marrow aspiration and biopsy 66 patients received a combination multi-agent CT with CHOP being the commonest regimen. 42 patients received 4 or lesser number of cycles of chemotherapy whereas 24received more than 4 cycles chemotherapy. Post radiotherapy, 41 out of 42 patients had a complete response at 3 months. Only 21patients had a complete response after chemotherapy. All patients received radiation (mostly involved field radiation) as a part of the treatment. The median radiation dose was 45 Gray (Range: 36 Gray-50 Gray). The radiation was planned by 2D fluoro simulation based technique in 37cases and by 3 Dimensional conformal radiation therapy (3DCRT) in 36 cases. Two patients were planned by the intensity modulated radiation therapy (IMRT) technique. IMRT was planned for one thyroid and one nasal cavity primary. 5 patients experienced relapse after a median follow up of 19 months. The median survival was not reached. The estimated two and three year survival were 92.9% (95%CI- 68.6- 95.35) and 88% (95%CI- 60.82 - 92.66) respectively. Univariate analysis revealed higher stage and poorer baseline performance status to be significantly associated with worse progression free survival. 5 patients progressed (relapse or primary disease progression) after treatment. Of the 5 patients, two patients were primary orbital NHL, two patients had NHL nasal cavity and one was NHL thyroid. Conclusions: Combined modality treatment in HNENL confers excellent disease control with acceptable side effects.

• Radiation Oncology Journal
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• v.13 no.2
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• pp.129-142
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• 1995

Purpose: Traditionally the patients with early stage non-Hodgkin's lymphoma of the head and neck was treated with radiotherapy. But the results were not satisfactory due to distant relapse. Although combined treatment with radiotherapy and chemotherapy was tried with some improved results and chemotherapy alone was also tried in recent years, the choice of treatment for the patients with early stage non-Hodgkin's lymphoma of the head and neck has not been defined Therefore, in order to determine the optimum treatment method, we analysed retrospectively the outcomes of the patients with Ann Arbor stage I and II non-Hodgkin's lymphoma localized to the head and neck who were treated at Severance Hospital. Materials and Methods: 159 patients with stage I and II non-Hodgkin's lymphoma localized to the head and neck were treated at our hospital from January, 1979 to December, 1992. Of these patients, 114 patients whose primary sites were Waldeyer's ring or nodal region, and received prescribed radiation dose and/or more than 2 cycles of chemotherapy. were selected to analyze the outcomes according to the treatment methods ( radiotherapy alone, chemotherapy alone. and combined treatment with radiotherapy and chemotherapy ). Results: Five year overall actuarial survival of the patients whose Primary site was Waldeyer's ring was $62.5\%.$ and that of the Patients whose primary site was nodal region was $53.8\%$ There was no statistically significant difference between survivals of both groups. Initial response rate to radiotherapy. chemotherapy, and combined treatment was $92\%,\;83\%,\;94\%$ respectively, and 5 year relapse free survival was $49.9\%,\;52.4\%,\;58.5\%$ respectively ( statistically not significant ). In the patients with stage I. 3 year relapse free survival of chemotherapy alone group was $75\%$ and superior to other treatment groups. In the Patients with stage II, combined treatment group revealed the best result with $60.1\%$ of 3 year relapse free survival. The effect of sequential schedule of each treatment method in the Patients who were treated by combined modality was analyzed and the sequence of primary chemotherapy + radiotherapy + maintenance chemotherapy showed the best result ( 3 year relapse free survival was $79.1\%).$ There was no significant survival difference between BACOP regimen and CHOP regimen. Response to treatment was only one significant (p(0.005) prognostic factor on univariate analysis and age and mass size was marginally significant ( p(0.1). On multivariate analysis, age (p=0.026) and mass size (p=0.013) were significant prognostic factor for the relapse free survival. Conclusion: In summary, the patients who have non-Hodgkin's lymphoma of the head and neck with stage I and mass size smaller than 10 cm, can be treated by chemotherapy alone, but remainder should be treated by combined treatment method and the best combination schedule was the sequence of initial chemotherapy followed by radiotherapy and maintenance chemotherapy.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.189.2-189.2
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• 2010

The purpose of this study is fatigue damage assessment for large sized casting parts (hub and mainframe) of the 3MW offshore wind turbine by computer simulation. Hub and mainframe durability assessment is necessary because wind turbine have to guarantee for 20 years. Fatigue life evaluation must be considered all of fatigue load conditions as the components are wind load transmission path. Palmgren-Miner linear damage accumulation hypothesis is applied for fatigue life estimation with stress-life approach. S-N curve for the spheroid graphite cast iron EN-GJS-400-18-LT is derived according to durability guidelines. Reduction factors were applied for survival probability, surface roughness, material quality and partial safety factor according to Germanischer Lloyd rules. To calculate fatigue damage, stress tensors, extracted from the unity load calculation from ANSYS is multiplied with time track of fatigue loads extracted from GH bladed. Damage accumulation is performed with all of fatigue load conditions at each finite element nodes. In this study maximum nodal damage value is under 1.0. casted parts are safe. This research was financially supported by the Ministry of Knowledge Economy(MKE), Korea Institute for Advancement of Technology(KIAT) and Honam Leading Industry Office through the Leading Industry Development for Economic Region.

• Nuclear Engineering and Technology
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• v.45 no.6
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• pp.707-720
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• 2013

We analyze piecewise homogenization with flux-weighted cross sections and preservation of averaged currents at the boundary of the homogenized domain. Introduction of a set of flux discontinuity ratios (FDR) that preserve reference interface currents leads to preservation of averaged region reaction rates and fluxes. We consider the class of numerical discretizations with one degree of freedom per volume and per surface and prove that when the homogenization and computing meshes are equal there is a unique solution for the FDRs which exactly preserve interface currents. For diffusion submeshing we introduce a Jacobian-Free Newton-Krylov method and for all cases considered obtain an 'exact' numerical solution (eight digits for the interface currents). The homogenization is completed by extending the familiar full assembly homogenization via flux discontinuity factors to the sides of regions laying on the boundary of the piecewise homogenized domain. Finally, for the familiar nodal discretization we numerically find that the FDRs obtained with no submesh (nearly at no cost) can be effectively used for whole-core diffusion calculations with submesh. This is not the case, however, for cell-centered finite differences.

• Journal of the Korean earth science society
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• v.35 no.5
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• pp.354-361
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• 2014

Fault plane solutions in North Korea and the northern part of the Yellow Sea ($37.5^{\circ}N-40.5^{\circ}N$, $124.5^{\circ}E-128.5^{\circ}E$) was studied for the earthquakes that occurred from November, 2008 to May, 2013. The analysis was based on the data collected from seismic networks in Korea and China. Fault plane solutions were obtained from P and SH wave polarities and SH/P amplitude ratioes. Most earthquakes exhibited predominantly strike-slip fault characteristics with NNE-SSW or WNW-ESE nodal planes. The P-axes trends are mainly NE-SW or ENE-WSW direction in the northern part of the Yellow Sea and inland area of North Korea except some areas in the Hwanghae province. Fault plane solutions and main axis of stress field in the study region were similar to those observed in the southern part of the Korean Peninsula.

• The korean journal of orthodontics
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• v.15 no.1
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• pp.7-22
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• 1985

The purpose of this study was to analyze the stress distribution and the displacement in the maxillary complex after the application of the reverse headgear. The direction of force was parallel to the occlusal plane. Orthopedic force,300gm, was applied to the maxilla of the dry human skull in a forward direction. The stress distribution and the displacement within the maxillary Complex was analyzed by a 3-dimensional finite element method. The results were as follows: 1. The stress distribution at the molar region was greater than that at the anterior. 2. The stress distribution at the lateral side of the premaxilla was greater than that at the middle aide, especially high stress was noted at the canine eminence. 9. Compressive stress was noted only at the frontozygomatic suture of the zygomatic arch. 4. A forward, upward, and sideward displacement was noted at the entire nodal points of the zygomaticomaxillary suture portion. A displacement with a slight rotation was observed on the transverse palatine suture. 5. The maximum stress was observed at the lateral side of the maxillary tuberosity area, and generally the forward and downward displacement was noted at all this area.

• Journal of Korean Society of Rural Planning
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• v.15 no.1
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• pp.47-59
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• 2009

The aim of this study is to analyze the green-tourism centrality considering spatial interaction using Gravity Model and social network method. The degree centrality and prestige centrality were applied as green-tourism centrality index. The rural amenity resources and human resources were counted as attraction factors, and a distance among villages was used as friction factor in gravity model. The weights of rural tourism amenity resources were calculated using the analytic hierarchy process(AHP) method and applied to evaluate green-tourism potentiality. The distance was measured with the shortest path among villages using geographic information system(GIS) network analysis. The spatial interaction from gravity model were employed as link weights between nodal points; a pair villages. Using the spatial interaction, the degree-centrality and prestige-centrality indices were calculated by social network analysis and demonstrated possibility of developing integrated green-tourism region centered on high centrality villages.