• Industrial Engineering and Management Systems
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• 제14권3호
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• pp.248-274
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• 2015

This study discusses a contract to promote collection and recycling of used products in a green supply chain (GSC). A collection incentive contract is combined with a reward-penalty contract. The collection incentive contract for used products is made between a retailer and a manufacturer. The reward-penalty contract for recycling used products is made between a manufacturer and an external institution. A retailer pays an incentive for collecting used products from customers and delivers them to a manufacturer with a product order quantity under uncertainty in product demand. A manufacturer remanufactures products using recyclable parts with acceptable quality levels and covers a part of the retailer's incentive from the recycled parts by sharing the reward from an external institution. Product demand information is assumed as (i) the distribution is known (ii) mean and variance are known. Besides, the optimal decisions for product quantity, collection incentive of used products and lower limit of quality level for recyclable parts under decentralized integrated GSCs. The analysis numerically investigates how (1) contract for recycling activity, (ii) product demand information and (iii) quality of recyclable parts affect the optimal operation for each GSC. Supply chain coordination to shift IGSC is discussed by adopting Nash Bargaining solution.

• Computers and Concrete
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• 제14권1호
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• pp.19-40
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• 2014

Reinforced concrete deep beams are structural beams with low shear span-to-depth ratio, and hence in which the strain distribution is significantly nonlinear and the conventional beam theory is not applicable. A strut-and-tie model is considered one of the most rational and simplest methods available for shear strength prediction and design of deep beams. The strut-and-tie model approach describes the shear failure of a deep beam using diagonal strut and truss mechanism: The diagonal strut mechanism represents compression stress fields that develop in the concrete web between diagonal cracks of the concrete while the truss mechanism accounts for the contributions of the horizontal and vertical web reinforcements. Based on a database of 406 experimental observations, this paper proposes a new strut-and-tie-model for accurate prediction of shear strength of reinforced concrete deep beams, and further improves the model by correcting the bias and quantifying the scatter using a Bayesian parameter estimation method. Seven existing deterministic models from design codes and the literature are compared with the proposed method. Finally, a limit-state design formula and the corresponding reduction factor are developed for the proposed strut-andtie model.

• 제3의학
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• 제1권1호
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• pp.37-44
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• 1996

This study has surveyed the problems raised through the standardization process of differentiation system and searched its solution, reaching the following conclusion. 1. The most serious problem is, most frequently occurred, an wilful application of differentiation system or constitutive classification for disease. 2. To overcome this wilfulness, we must make a definite understanding of the origin and its applicative limit of the theory. 3. And it must be preceded for a correct and objective differentiation to standardize in all choice of the differential diagnostics and its applicative condition. 4. To establish such a corresponding diagnostic scheme, it must be generally agreed on an individuality and inevitability of the suitability to differentiation principles. 5. And, though we can make a prescription through the frequency, degree, and clarified cause of the symptom, its flexibility of application must not be necessarily, ignored. 6. As this study for standardizing the disharmony between liver and pancreas(肝脾不調) shows, accordingly, we must begin by scrutinizing and defining what the chief cause, head, and inevitable symtoms are and discern them from its affinities, making necessarily a great deal attention to minute feelings and degree about its individual symptoms. On the ground of these recognition, we must go further to establish a general standardization and try to get a specific study series.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2011년도 후기공동학술대회 논문집
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• pp.73-73
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• 2011

In fact, asynchronous motors are used widely. Asynchronous motors which have large power (compared to the source supplies) is needed to start them in various methods. The theory of application reduced voltage to motor's stator or variable resistor fed rotor for the purpose of altering the motor's torque and power consumption characteristics is an idea that has existed for many years. These concepts have flourished mainly due to the need to limit torque and limited generator/power distribution capabilities. However, how can know exactly the time of switching steps with different types of motors as well as load characteristics is very difficult. This paper focuses on the design and development mathematical models of motor[1][2], load, ACB, asynchronous machine and then is implemented in SIMULINK in order to calculate this time, special on ships where power generation station is limited. The simulation results are both compared and discussed in detail so that it can apply to conclude the most suitable and applicable starting time for new system with various motors and load.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.459-464
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• 2000

In this paper, it verifies the relationships between wheel velocity and surface roughness with the mirror surface grinding using electrolytic in-process dressing (ELID). In the general, as wheel velocity is high, surface roughness is better on the base of grinding theory. However, the relationships between wheel velocity and surface roughness is undefined due to the effect of electro-chemical dressing and the characteristics of materials. According to above relationships, ELID grinding experiment is carried out by following the change of wheel velocity. As the result of this study, it is found that surface roughness is not better as linearly as the increase of wheel velocity, but the limit of wheel velocity exists according to the characteristics of materials. Also, in contradiction to the present trend of high wheel velocity of manufacturing system for high surface integrity, it is able to expected to the base on the development of new ultra precision grinding method with the practicality of mirror surface grinding using ELID grinding method.

• Geomechanics and Engineering
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• 제14권1호
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• pp.19-27
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• 2018

It follows from the basic principles of mechanics of deformable solids relating to the strength, stability and propagation of elastic waves that the Earth's inner core cannot exist in the form of a spherical structure in the assumed thermobaric conditions and calculation values of physico-mechanical parameters. Pressure level reaches a value that is significantly greater than the theoretical limit of medium strength in the model approximations at the surface of the sphere of the inner core. On the other hand, equilibrium state of the sphere is unstable on the geometric forming at much lower loads under the influence of the "dead" surface loads. In case of the action of "follower" loads, the assumed pressure value on the surface of the sphere is comparable with the value of the critical load of "internal" instability. In these cases, due to the instability of the equilibrium state, propagation of homogeneous deformations becomes uneven in the sphere. Moreover, the elastic waves with actual velocity cannot propagate in such conditions in solid medium. Violation of these fundamental conditions of mechanics required in determining the physical and mechanical properties of the medium should be taken into account in the integrated interpretations of seismic and laboratory (experimental) data. In this case, application of the linear theory of elasticity and elastic waves does not ensure the reliability of results on the structure and composition of the Earth's core despite compliance with the required integral conditions on the mass, moment of inertia and natural oscillations of the Earth.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.837-842
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• 2000

In the coiling process of helical steam generator tubes of integral reactor SMART, a considerable amount of spring back, which induces dimensional inaccuracy and difficulty in fabrication, has been arised. In this research, an analytical model was derived to evaluate the amount of the spring back for steam generator tubes. The model was developed on the basis of beam theory and elastic-perfectly plastic material property. This model was extended to consider the effect of plastic hardening and the effect of the tensile force on the spring back phenomena. Parametric studies were performed for various design variables of steam generator tubes in order to minimize the spring back in the design stage. A sensitivity analysis has shown that the low yield strength, the high elastic modulus, the small helix diameter, and the large tube diameter result in a small amount of the spring back. The amount of the spring back can be controlled by the selection of adequate design values in the basic design stage and reduced to an allowable limit by the application of the tensile force to the tube during the coiling process.

• 한국정보과학회논문지:시스템및이론
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• 제26권9호
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• pp.1064-1072
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• 1999

크기가 n인 하이퍼큐브 다중컴퓨터를 위한 대표적인 동적인 재분배 방법인 DEM(Dimension Exchange Method) 기법으로 양자화된 부하를 분배할 때 분배 후 각 프로세서가 갖는 부하의 크기는 최악의 경우, logn~단위부하 만큼 분배오차를 갖게 된다. 이러한 오차를 억제하기 위하여 본 논문에서는 두 프로세서간에 부하를 분배할 때, 가능하면 동일 유형(홀수개 또는 짝수개)의 단위부하를 동일 방향으로 재분배하는 기법을 제안하였다. 그 결과 최대 분배 오차를 LCEIL logn over {2} RCEIL 까지 줄일 수 있었다. 시뮬레이션에 의한 실험을 통해 기존 DEM 방법에 비해 약 30% 정도 시스템의 속도가 향상됨을 보임으로써 제안된 기법이 DEM 기법보다 타당성함을 입증하였다.

• 한국정보과학회논문지:시스템및이론
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• 제33권12호
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• pp.859-866
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• 2006

그리드 포탈 서비스는 기존의 어플리케이션 기반 그리드 서비스가 갖는 시간적 공간적 제약을 극복하여 보다 유연한 연구 환경을 제공한다. 그러나 사용자 인터페이스와 같은 사용자 요구 사항은 개발 기간 동안 불분명하기도 하고 자주 변하기도 한다. 그러므로 그리드 서비스를 위한 사용자 인터페이스를 만들고 유지 관리하는 비용을 줄일 수 있는 방안이 필요하다. 본 논문에서는 유저 인터페이스 개발이 보다 쉽고 코드의 재사용률을 증가시킬 수 있는 객체 기반의 컨트롤 모델을 제안한다. 이 모델에서는 프레젠테이션 페이지의 구조를 보다 명확히 기술할 수 있고 액션들을 구현하는 것이 보다 쉽고 간단하다.

• 대한토목학회논문집
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• 제12권3호
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• pp.1-15
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• 1992

본 논문에서는 열 두가지의 가능한 지지조건을 갖는 연속 곡평면 2방향 슬래브 시스템에 대하여 실용적이고 간편한 수치해석과 최적 설계 방법을 제시하였다. 얇은 곡평판의 탄성이론에 의하여 유도된 설계모멘트 계수를 이용하여, 구조해석을 하는 수치해석 방법을 본 연구에서는 사용하였다. 최적화의 결과는 한계상태 설계법에 의해서 정의된 feasible 영역내에서 결정되도록 유도하였으며 슬래브의 주재료 경비함수를 변형시켜 유도한 목적함수는 한계상태 설계의 규정에 따라 역학적 거동의 문제와 사용성 제약조건을 모두 만족하연서 최적화에 이르도록 하였다. 형성된 최적화 문제는 고차의 비선형 문제로 유도 되었으며 이 비선형 최적화 문제를 연속 선형계획법을 이용하여 해석하므서 슬래브의 유효깊이와 중간대 및 주열대의 단위폭당 변형시킨 철근비들의 최적 설계변수들을 구하였다.