• 한국소음진동공학회논문집
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• 제13권5호
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• pp.384-392
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• 2003

The fuel rods in the Pressurized water reactor are continuously supported by a spring system called a spacer grid which is one of the main structural components for the fuel rod cluster(fuel assembly). The fuel rods vibrate within the reactor due to coolant flow. Since the vibration, which is called flow-induced vibration(FIV) can wear away the surface of the fuel rod, it is important to understand it's vibration characteristics. In this paper, the vibration analyses and the tests for the dummy rods supported by New Doublet(ND) spacer grids are described. A new FE model which reflects the contact area between the rod and ND spacer grid spring is developed to replace the previous one by which a good agreement could not be obtained with the vibration test. The natural frequency and mode shape calculated by both the Previous FE model and the new one are compared with those of experiment for a single-spanned rod supported by two ND spacer grids. The results of the new model showed good agreement with the experiment compared with those of previous model. In addition. the new FE model is applied to the vibration analysis for the dummy rod of 2.189 mm tall continuously supported by five ND spacer grids. It is also obtained that the analysis results of the new FE model well agreed to experiment ones as the single-spanned rod.

• 농업과학연구
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• 제15권1호
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• pp.114-122
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• 1988

This paper aims to identify the characteristics of the tenant farm's income compared with farm household consumption. Farm household surplus is a critical criteria for the reproduction of agriculture. The degree of self sufficiency of farm household consumption according to agricultural income was rapidly decreasing for the period of 1980's. Only 78.9 percents of farm household consumption was earned by agricultural income. Tenant farms were classified according to the following characteristics; self-supported, semi self-supported, leased, deleted, over-consumption. Self-supported tenants are one of the backbones of Korea's future agriculture, because they are able to meet their household needs by only their farm work without other income producing endeavors. The rent paid by those tenants surveyed was estimated at 26.2 percents of their farm household income. However, the national average for such rental payment is equivalent to 4.7 percents of farm household income. 63 percents of paddy rental fee was paid by inkind of rice and 80 percents of the upland rental fee was paid by cash. Self-supported farms as 20 percents of total surveyed should be the target of agricultural price policy and semi self-supported & over-consumption farms as 30 percents be that of rural development policy, and the other half be that of social welfare policy.

• 인터넷정보학회논문지
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• 제16권3호
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• pp.71-77
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• 2015

본 논문에서는 대규모 워크플로우 기반 소셜 네트워크를 위한 추정 근접 중심도 랭킹 알고리즘을 구현하고, 그에 대한 성능 분석을 수행한다. 기존의 근접 중심도 분석 방법은 특정 노드와 다른 모든 노드들 간의 최단거리를 구하므로 네트워크의 크기가 커짐에 따라 근접 중심도 분석 시간이 기하급수적으로 증가하는 문제점을 가진다. 이로 인해 대규모 소셜 네트워크의 근접 중심도 랭킹 과정에도 계산시간 문제를 가진다. 이러한 문제점을 개선하고자 본 논문에서는 추정기법을 활용한 근접 중심도 랭킹 알고리즘을 구현하며 기존 알고리즘과의 성능 분석을 수행한다. 이는 약 50%의 계산 시간 단축 결과를 보여주었다.

• 한국지진공학회논문집
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• 제22권6호
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• pp.311-322
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• 2018

As a method of seismic-design for pile-supported wharves, equivalent static analysis, response spectrum analysis, and time history analysis method are applied. Among them, the response spectrum analysis is widely used to obtain the maximum response of a structure. Because the ground is not modeled in the response spectrum analysis of pile-supported wharves, the amplified input ground acceleration should be calculated by ground classification or seismic response analysis. However, it is difficult to calculate the input ground acceleration through ground classification because the pile-supported wharf is build on inclined ground, the methods to calculate the input ground acceleration proposed in the standards are different. Therefore, in this study, the dynamic centrifuge model tests and the response spectrum analysis were carried out to calculate the appropriate input ground acceleration. The pile moment in response spectrum analysis and the dynamic centrifuge model tests were compared. As a result of comparison, it was shown that the response spectrum analysis results using the amplified acceleration in the ground surface were appropriate.

• Structural Engineering and Mechanics
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• 제59권4호
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• pp.621-652
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• 2016

A new cable-supported bridge model consisting of suspension parts, self-anchored cable-stayed parts and earth-anchored cable-stayed parts is presented. The new bridge model can be used for suspension bridges, cable-stayed bridges, cable-stayed suspension bridges, and partially earth-anchored cable-stayed bridges by varying parameters. Based on the assumption that each structural member is in either an axial compressive or tensile state, and the stress in each member is equal to the allowable stress of the material, the material quantity for each component is calculated. By introducing the unit cost of each type of material, the estimation formula for the cost of the new bridge model is developed. Numerical examples show that the results from the estimation formula agree well with that from the real projects. The span limit of cable supported bridge depends on the span-to-height ratio and the density-to-strength ratio of cables. Finally, a parametric study is illustrated aiming at the relations between three key geometrical parameters and the cost of the bridge model. The optimization of the new bridge model indicates that the self-anchored cable-stayed part is always the dominant part with the consideration of either the lowest total cost or the lowest unit cost. It is advisable to combine all three mentioned structural parts in super long span cable supported bridges to achieve the most excellent economic performance.

• 간호행정학회지
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• 제22권1호
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• pp.67-79
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• 2016

Purpose: To develop strategies for research and development (R&D) in nursing service based on the policy direction of government supported R&D in Korea. Methods: This was a descriptive study to develop strategies for promoting R&D in nursing by analyzing investment trends and status quo, policy directions, and implementation of the details of government supported R&D through government reports, websites of relevant agencies and literature reviews. Results: Few nursing experts participated in clinical research on overcoming major diseases and in R&D for well-being and care. Development of nursing topics that meet the direction of government supported R&D were lacking. Insufficient implementation of nursing service R&D in a timely manner equipped with a performance-based system. Few research studies in R&D projects that included research using big data or contributing to developing medical instruments. Finally, an insufficient number of nursing specialists participated on government R&D advisory committees. Conclusion: For nursing service R&D development efforts should be toward quantitative expansion and qualitative improvements by sensitively recognizing policy direction of government supported R&D. The promotional capacity of nursing service R&D must be reinforced through a multidisciplinary approach and collaborative association with other professionals and the inclusion of nurse specialists on government R&D advisory committees.

• The Journal of Advanced Prosthodontics
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• 제5권3호
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• pp.326-332
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• 2013

PURPOSE. The purpose of this study was to compare stress distributions of implant-supported crown placed in fibula bone model with those in intact mandible model using three-dimensional finite element analysis. MATERIALS AND METHODS. Two three-dimensional finite element models were created to analyze biomechanical behaviors of implant-supported crowns placed in intact mandible and fibula model. The finite element models were generated from patient's computed tomography data. The model for grafted fibula was composed of fibula block, dental implant system, and implant-supported crown. In the mandible model, same components with identical geometries with the fibula model were used except that the mandible replaced the fibula. Vertical and oblique loadings were applied on the crowns. The highest von Mises stresses were investigated and stress distributions of the two models were analyzed. RESULTS. Overall stress distributions in the two models were similar. The highest von Mises stress values were higher in the mandible model than in the fibula model. In the individual prosthodontic components there was no prominent difference between models. The stress concentrations occurred in cortical bones in both models and the effect of bicortical anchorage could be found in the fibula model. CONCLUSION. Using finite element analysis it was shown that the implant-supported crown placed in free fibula graft might function successfully in terms of biomechanical behavior.

• 호남수학학술지
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• 제36권4호
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• pp.831-852
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• 2014

The obstacle shape reconstruction problem has been known to be difficult to solve since it is highly nonlinear and severely ill-posed. The use of local or locally supported basis functions for the problem has been addressed for many years. However, to the authors' knowledge, any research report on the proper usage of local or locally supported basis functions for the shape reconstruction has not been appeared in the literature due to many difficulties. The aim of this paper is to introduce the general concepts and methodologies for the proper choice and their implementation of locally supported basis functions through the two-dimensional Helmholtz equation. The implementations are based on the complex nonlinear parameter estimation (CNPE) formula and its robust algorithm developed recently by the authors. The basic concepts and ideas are simple. The derivation of the necessary properties needed for the shape reconstructions are elementary. However, the capturing abilities for the local geometry of the obstacle are superior to those by conventional methods, the trial and errors, due to the proper implementation and the CNPE algorithm. Several numerical experiments are performed to show the power of the proposed method. The fundamental ideas and methodologies described in this paper can be applied to many other shape reconstruction problems.

• 재활복지공학회논문지
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• 제9권1호
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• pp.11-15
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• 2015

2004년부터 실시되고 있는 고용지원을 위한 보조공학서비스를 제공하고 있는 센터는 중앙기관 1개와 그 외 18개지사의 한국장애인고용공단이다. 선행 연구에서 수요자의 만족도 조사를 통해 서비스의 필요성이 입증되었다. 그러나 센터의 전문성을 향상시키고, 양적 서비스에서 질적 서비스를 실시할 필요성이 나타나면서 수요분석을 통해 고용지원 보조공학 센터의 설립이 필요하다고 할 수 있다. 2013년도 한국장애인고용공단의 보조공학기기지원사업의 성과의 분석 통해 보조공학기기 수용에 대한 추계율을 분석하였다. 국가 및 지자체에서 지원하고 관리하는 센터의 경우의 보조공학서비스가 필요한 장애인 수요자를 지원하기에 인력 및 지원이 부족하다고 나타났다. 이를 통해 증가하는 장애인 인구수와 그 들의 다양한 욕구를 해결 할 수 있는 고용지원 보조공학 센터는 설립이 필요하다고 조사되었다.

• 한국소음진동공학회논문집
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• 제13권7호
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• pp.562-569
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• 2003

An iterative modal analysis approach is developed to determine the effect of transverse open cracks on the dynamic behavior of simply supported pipe conveying fluid subject to the moving mass. The equation of motion Is derived by using Lagrange’s equation. The influences of the velocity of moving mass and the velocity of fluid flow and a crack have been studied on the dynamic behavior of a simply supported pipe system by numerical method. The presence of crack results In higher deflections of pipe. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments i.e. the crack is modelled as a rotational spring. Totally. as the velocity of fluid flow and the crack severity are increased, the mid-span deflection of simply supported pipe conveying fluid Is Increased. The time which produce the maximum dynamic deflection of the simply supported pipe Is delayed according to the increment of the crack severity.