• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권3호
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• pp.243-259
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• 2016

The Richards equation for water movement in unsaturated soil is highly nonlinear partial differential equations which are not solvable analytically unless unrealistic and oversimplifying assumptions are made regarding the attributes, dynamics, and properties of the physical systems. Therefore, conventionally, numerical solutions are the only feasible procedures to model flow in partially saturated porous media. The standard Finite element numerical technique is usually coupled with an Euler time discretizations scheme. Except for the fully explicit forward method, any other Euler time-marching algorithm generates nonlinear algebraic equations which should be solved using iterative procedures such as Newton and Picard iterations. In this study, lumped mass and distributed mass in the frame of Picard and Newton iterative techniques were evaluated to determine the most efficient method to solve the Richards equation with finite element model. The accuracy and computational efficiency of the scheme and of the Picard and Newton models are assessed for three test problems simulating one-dimensional flow processes in unsaturated porous media. Results demonstrated that, the conventional mass distributed finite element method suffers from numerical oscillations at the wetting front, especially for very dry initial conditions. Even though small mesh sizes are applied for all the test problems, it is shown that the traditional mass-distributed scheme can still generate an incorrect response due to the highly nonlinear properties of water flow in unsaturated soil and cause numerical oscillation. On the other hand, non oscillatory solutions are obtained and non-physics solutions for these problems are evaded by using the mass-lumped finite element method.

• 한국해양공학회지
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• 제21권6호
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• pp.81-86
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• 2007

In order to eliminate the hydration heat of mass concrete, this paper reports the results of hydration heat control in mass concrete using the OCHP (Oscillating capillary tube heat pipe). In the summarized results of the mock up experiments, distributing the heat pipe at 300 mm intervals based on the center of the test specimen was the most effective. A 200 mm turn interval for the heat pipe was measured to be the most appropriate, taking into account the reinforcement placing at the actual site. Therefore, when the hydration heat control method using the heat pipe developed in this study is applied, not only canconstruction efficiency & a reduction in the necessary construction time be expected, but so can outstanding economical effects.

• 정보처리학회논문지A
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• 제12A권4호
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• pp.321-326
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• 2005

본 논문에서는 질점-스프링 모델(mass-spring model)에 기반한 대화형 천 시뮬레이션(interactive cloth simulation) 기법을 제시하며, 특히 소수의 질점들(mass-points)에 상대적으로 강한 힘이 가해졌을 경우 사실적으로 천을 시뮬레이션하는 방법에 초점을 맞추었다. 본 논문에서 제시하는 방법은 소수의 점들에 대해 가해진 힘을 모든 질점들에 분산시킴으로써 의사 실시간(pseudo real-time) 내에 시뮬레이션을 수행하며, 이는 기존의 방법들에 비해 수행속도 면에서 매우 효율적이다. 또한, Provot[9]의 역동역학 방법(inverse dynamic method)을 사용하여 초탄성(super-elasticity) 현상을 해결한 뒤, 인접한 질점 간의 각도를 조정함으로써 초탄성 효과에 의해 발생하는 지그재그(zigzag) 현상을 제거하여 사실적으로 천을 시뮬레이션한다.

• Structural Engineering and Mechanics
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• 제68권1호
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• pp.121-130
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• 2018

This study deals with optimum geometry design of laterally loaded piles in a Winkler's medium through the Fully Stressed Design (FSD) method. A numerical algorithm distributing the mass by means of the FSD method and updating the moment by finite elements is implemented. The FSD method is implemented here using a simple procedure to optimise the beam length using an approach based on the calculus of variations. For this aim two conditions are imposed, one transversality condition at the bottom end, and a one sided constraint for moment and mass distribution in the lower part of the beam. With this approach we derive a simple condition to optimise the beam length. Some examples referred to different fields are reported. In particular, the case of laterally loaded piles in Geotechnics is faced.

• Structural Engineering and Mechanics
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• 제85권1호
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• pp.55-64
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• 2023

Energy-based seismic design and evaluation methods are promising to be involved in the next generation design codes. Accordingly, determining the distribution of earthquake input energy demand among floor levels is quite imperative in order to develop an energy-based seismic design procedure. In this paper, peak floor input energy demands are achieved from relative input energy response histories of several reinforced concrete (RC) frames. A set of 22 horizontal acceleration histories selected from recorded near-fault earthquakes and scaled in time domain to be compatible with the elastic acceleration design spectra of Turkish Seismic Design Code are used in time history analyses. The distribution of the computed input energy per mass values and the arithmetic means through the height of the considered RC frames are presented as a result. It is found that spatial distribution of input energy per mass is highly affected by the number of stories. Very practical yet consistent formulation of distributing the total input energy to story levels is achieved, as a most important contribution of the study.

• 한국조리학회지
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• 제14권2호
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• pp.153-169
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• 2008

The purpose of this study is to determine the effects of production strategies operated by franchisors in the food service industry on the franchisees' culinary competence and subsequently franchisees' satisfaction with performance and recontract intention. In order to accomplish this purpose, two franchised enterprises which used mass-purchasing and mass-producing before distributing to each franchisee for the production strategies were participated and eventually 287 franchisees responded to this survey. Factor analysis and Cronbach's alpha showed the validity and internal consistency for the survey questionnaire. LISREL(8.72) was used to test the relationships between variables; production strategy, culinary competences, franchisee satisfaction, and recontract intention of the franchisees. The results present that the franchisees' satisfaction with the management system, quality of distribution, and quality of foods influenced on differentiation performance and supply performance of franchisees. On cost performance, only satisfaction with the food cost had an impact. The higher franchisee satisfaction with the franchisees' operations was, the higher recontract intention was in the franchise business. The results suggest the critical points for improving foodservice supplying system as well.

• 대한조선학회지
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• 제14권3호
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• pp.13-22
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• 1977

The hydrodynamic forces acting on a forced oscillating 2-dimensional cylinder on a free surface of a fluid of a finite depth are calculated by distributing singularities on the immersed body surface. And the Haskind-Newman relation in a fluid of a finite depth is derived. The wave exciting force of the cylinder to an oscillation is also calculated by using the above relation. The method is applied to a circular cylinder swaying in a water of finite depth, and then, to a rectangular cylinder heaving, swaying, and rolling. The results of above cases give a good agreement with those by earlier investigators such as Bai, Keil, and Yeung. Also, this method is applied to a Lewis form cylinder with a half beam-to-draft ratio of 1.0 and a sectional area coefficient of 0.941, and to a bulbous section cylinder which is hard to represent by a mapping function. The results reveal that the hydrodynamic forces in heave increase as the depth of a water decrease, but in sway or roll, the tendency of the hydrodynamic forces is difficult to say in a few words. The exciting force to heave for a bulbous section cylinder becomes zero at two frequencies. The added mass moment of inertia for roll is seemed to mainly depend on the sectional shape than the water depth.

• 한국의류학회지
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• 제35권4호
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• pp.442-454
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• 2011

This study analyzed the present uniform satisfaction, uniform satisfaction followed by physical satisfaction, attitude for uniform, purchase attitude for uniform, satisfaction for design, preference for design, and attitude for uniform alteration behavior by distributing questionnaires to high school girl students in Daejeon City. The results of the study are as follows. The study distributed questionnaires to 319 high school girl students in Daejeon City and analyzed the satisfaction factors for their uniforms. As the result, this study induced four factors. The average value of each factor appeared in order of symbolic satisfaction, management satisfaction, activity satisfaction, and aesthetic satisfaction to show that high school girl students were the most dissatisfactory in aesthetic satisfaction. When the study examined the realities of uniform alteration, it showed that 71.2% of them altered their uniforms. In the alteration of a jacket and a skirt, they altered their jackets shortly and tightly in the mass in the order of: waist measurement, jacket length, breast width, shoulder width, and girth of the chest in a jacket. For a skirt, they altered their skirts tightly as a jacket in the order of: skirt length, waist measurement, and the girth of hip.

• 한국기계가공학회지
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• 제9권3호
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• pp.83-88
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• 2010

This study aimed to enhance the durability by distributing the stress concentration at the contact and increasing the mechanical characteristics, as well as by changing the surface shape for LIP in the low-pressure seal among oil seals installed to the power steering of automotive. Accordingly, results were derived from comparisons and reviews with oil seals under the existing mass production by carrying out the performance tests after designs and productions are done with the addition of embo shapes on the surface of LIP in the low-pressure seal. As a result of this study, it has been identified that the durability of oil seals with the addition of embo shapes was enhanced with higher radial force and less variation in the internal diameter for the LIP. In addition, it was seen that the sealing ability for those oil seals is superior to the existing oil seals as their rotational torque values are less than those of the existing oil seals.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.49-50
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• 2016

Recently in Korea, some studies on concrete that mass quantity of additives are substituted in order to respond to the government's Low Carbon Green Growth Policy are being conducted. As on of additives, FA as an industrial by-product is used in a large quantity. However, In some of the domestic FA refineries, since some quantity of concrete without passing through the refining process is released for sales for the reasons of the shortening of production time and the cost reduction, etc., it exerts a bad influence on the quality of concrete. Therefore, in this study, there was implemented an experiment on the effects of using an extreme quality of FA which is available for distributing domestically on the engineering characteristics of lean mortar. As a result, it was found that the quality of FA exerts its effect on the compression strength bigger than the flow property or the air volume.