• Structural Engineering and Mechanics
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• 제27권5호
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• pp.589-607
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• 2007

Two series of tests were conducted to investigate the behavior of local thin jacketing for the retrofitting of reinforced concrete (RC) columns. In the first series, four full-scale RC columns with a height of 400 cm and a 30 cm square cross-section were tested under constant axial load and reversed cyclic lateral displacements. The heavily damaged columns were retrofitted with local thin jacketing. Self-compacting concrete (SCC) was used in the production of 7.5 cm thick, four-sided jacketing. The height of the jacketing was 100 cm for one specimen and 200 cm for all others. In the second series, the retrofitted columns were retested with the same axial load and displacement history. The effectiveness of local thin jacketing in the retrofitting of RC columns was examined with respect to lateral strength, stiffness, inelastic load-deformation behavior and energy dissipation.

• Journal of Welding and Joining
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• 제24권2호
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• pp.48-56
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• 2006

The fatigue strength of the welds is affected by such factors as the weld geometry, microstructures, tensile properties and residual stresses caused by fabrication. It is very important to evaluate the structural integrity of the welds in nuclear power plant because the weldment undergoes the most of damage and failure mechanisms. In this study, the fatigue assessments for a reactor vessel outlet nozzle with the weldment to the piping system are performed considering the welding residual stresses as well as the effect of local brittle zone in the vicinity of the weld fusion line. The analytical approaches employed are the microstructure and mechanical properties prediction by semi-analytical method, the thermal and stress analysis including the welding residual stress analysis by finite element method, the fatigue life assessment by following the ASME Code rules. The calculated results of cumulative usage factors(CUF) are compared for cases of the elastic and elasto-plastic analysis, and with or without residual stress and local brittle zone effects, respectively. Finally, the fatigue life of reactor vessel outlet nozzle weld is slightly affected by the local brittle zone and welding residual stresses.

• 한국주거학회논문집
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• 제17권3호
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• pp.51-60
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• 2006

Ten years have passed since the Demolishing Walls Campaign has started in Daegu. Recently, the campaign influenced to the other cities in Korea, such as Seoul, Incheon and Busan with various names regarding cities' circumstances. In these context, the study aims to highlight the identity of the Demolishing Walls Campaign compare Daegu with other cities where similar movement has started. In addition, the study evaluates the campaign in terms of physical, psychological and economical aspects to suggest some practical suggestion for the development of the campaign based on questionnaire survey. The research findings are as follows. The research shows that the identity of the Daegu Campaign is started by bottom-up approach based on citizens' participation compare with others cities' campaigns which are mainly started by the local government so called top-down method. The Daegu campaign influences the local people aware of their potential abilities in positively improving urban environment. The results of survey also highlights the advantages of green spaces which by the campaign in terms of environmental and economical aspects. Newly generating urban greens accept and store heat which Influences urban microclimate conditions and it possibly affects energy savings of the city. Most of survey participants eager to continue this campaign which shows positive results in various aspects by the local people. Therefore, the city government building a coalition of local people, NGOs, and interest group to keep the identity of the campaign in Daegu.

• 한국조리학회지
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• 제13권3호
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• pp.68-79
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• 2007

The purpose of this study was to contribute to merchandising of native local foods. This study was designed to standardize the recipes and to analyze the nutrients of native local foods in Gijang region such as 'Myeolchijjigae', 'Galchijjigae' and 'Maejipjjim'. The test recipe for each food was prepared according to the information obtained from the personal interview of Gijang natives and then supplied for the sensory evaluation. After that, CAN Pro 2.0 was used for the nutritional evaluation. The results are as follows : Myeolchijjigae was preferred when radishes and traditional soybean paste were added. Galchijjigae was more liked when young pumpkins, mixed soy sauce and soybean paste were added. Maejipjjim was preferred with Aeji(Codium adhaerens), Warty sea squirt(Styela clava), soybean paste and powdered perilla seed(Perilla frutescens var. japonica) added. The analysis of nutrient composition revealed that in general energy content was low whereas protein content was as high as recommended requirement in Myeolchijjigae and Maejipjjim. Calcium and phosphorus were high in Myeol-chijjigae, vitamin A in Galchijjigae, and vitamin A, B_6$, folic acid, phosphorus and iron in Maejipjjim.

• Journal of Theoretical and Applied Mechanics
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• 제2권1호
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• pp.31-50
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• 1996

In this paper, a finite element analysis based on the local approach concept to fracture in the continuum damage mechanics is performed to analyze ductile fracture in two dimensional quasi-static state. First an isotropic damage model based on the generalized concept of effective stress is proposed for structural materials in the context of large deformation. In this model, the stiffness degradation is taken as a measure of damage and so, the fracture phenomenon can be explained as the critical deterioration of stiffness at a material point. The modified Riks' continuation technique is used to solve incremental iterative equations. Crack propagation is achieved by removing critically damaged elements. The mesh size sensitivity analysis and the simulation of the well known shearing mode failure in plane strain state are carried out to verify the present formulation. As numerical examples, an edge cracked plate and the specimen with a circular hole under plane stress are taken. Load-displacement curves and successively fractured shapes are shown. From the results, it can be concluded that the proposed model based on the local approach concept in the continuum damage mechanics may be stated as a reasonable tool to explain ductile fracture initiation and crack propagation.

• 정보처리학회논문지B
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• 제15B권6호
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• pp.501-506
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• 2008

기존 스네이크 알고리즘은 에너지 함수의 정의에 의해 복잡한 객체의 윤곽을 추출하는데 어려움이 있고, GVF 방법은 에너지 맵 계산 시간이 많이 소요되는 문제점이 있다. 본 논문에서는 빠르고, 복잡한 객체의 윤곽을 잘 추출하는 방법을 제안한다. 객체 윤곽의 복잡도는 곡률로 정의하여 곡률 값이 임계치 이상이면 스네이크 포인트를 추가하여 객체의 윤곽을 추출하였다. 다수의 복잡한 영상에 실험을 통해 계산속도 및 윤곽 추출 성능을 개선하는 결과를 보여준다.

• Geomechanics and Engineering
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• 제20권3호
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• pp.175-189
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• 2020

A set of relatively simple five local shear and tension failure variables is presented and then implemented into a generalized poroelastic hydromechanical numerical model to analyze failure potential and stability of variably saturated geologic media. These five local shear and tension failure variables are formulated from geometrical relationships between the Mohr circle and the Mohr-Coulomb failure criterion superimposed with the tension cutoff, which approximate together the Mohr effective stress failure envelope. Finally, fully coupled groundwater flow and land deformation in two variably saturated geologic media, which are associated with a slope (Case 1) and a tunnel (Case 2), respectively, and their failure potential and stability are simulated using the resultant hydromechanical numerical model. The numerical simulation results of both cases show that shear and tension failure potential and stability of variably saturated geologic media can be analyzed numerically simply and efficiently and even better by using the five local shear and tension failure variables as a set than by using the conventional factors of safety against shear and tension failures only.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.327-339
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• 2018

This article presents a new global-local hybrid coarse-mesh finite difference (HCMFD) method for efficient parallel calculation of pin-by-pin heterogeneous core analysis. In the HCMFD method, the one-node coarse-mesh finite difference (CMFD) scheme is combined with a nodal expansion method (NEM)-based two-node CMFD method in a nonlinear way. In the global-local HCMFD algorithm, the global problem is a coarse-mesh eigenvalue problem, whereas the local problems are fixed source problems with boundary conditions of incoming partial current, and they can be solved in parallel. The global problem is formulated by one-node CMFD, in which two correction factors on an interface are introduced to preserve both the surface-average flux and the net current. Meanwhile, for accurate and efficient pin-wise core analysis, the local problem is solved by the conventional NEM-based two-node CMFD method. We investigated the numerical characteristics of the HCMFD method for a few benchmark problems and compared them with the conventional two-node NEM-based CMFD algorithm. In this study, the HCMFD algorithm was also parallelized with the OpenMP parallel interface, and its numerical performances were evaluated for several benchmarks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권1호
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• pp.58-73
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• 2014

As is well known, cooperative sensing can significantly improve the sensing accuracy as compared to local sensing in cognitive radio networks (CRNs). However, a large number of cooperative secondary users (SUs) reporting their local detection results to the fusion center (FC) would cause much overhead, such as sensing delay and energy consumption. In this paper, we propose a fast cooperative sensing scheme, called double threshold fusion (DTF), to reduce the sensing overhead while satisfying a given sensing accuracy requirement. In DTF, FC respectively compares the number of successfully received local decisions and that of failed receptions with two different thresholds to make a final decision in each reporting sub-slot during a sensing process, where cooperative SUs sequentially report their local decisions in a selective fashion to reduce the reporting overhead. By jointly considering sequential detection and selective reporting techniques in DTF, the overhead of cooperative sensing can be significantly reduced. Besides, we study the performance optimization problems with different objectives for DTF and develop three optimum fusion rules accordingly. Simulation results reveal that DTF shows evident performance gains over an existing scheme.

• Advances in nano research
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• 제8권1호
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• pp.37-47
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• 2020

This work focuses on the behavior of non-local shear deformation beam theory for the vibration of functionally graded (FG) nanobeams with porosities that may occur inside the functionally graded materials (FG) during their fabrication, using the non-local differential constitutive relations of Eringen. For this purpose, the developed theory accounts for the higher-order variation of transverse shear strain through the depth of the nanobeam. The material properties of the FG nanobeam are assumed to vary in the thickness direction. The equations of motion are derived from Hamilton's principle. Analytical solutions are presented for a simply supported FG nanobeam with porosities. The validity of this theory is verified by comparing some of the present results with other higher-order theories reported in the literature, the influence of material parameters, the volume fraction of porosity and the thickness ratio on the behavior mechanical P-FGM beam are represented by numerical examples.