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        검색결과 87

        1.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        By developing molds and facilities to horizontally mold the functional part of the dry-cast concrete block, We intend to develop molds and a series of facilities to horizontally mold the functional part of the dry-cast concrete block to increase production per cycle while maintaining existing production methods and major facilities. In order to do so, CAE analysis is first required to develop molds and facilities for horizontally molding the functional part of the drycast concrete block in the horizontal direction. The procedure will be carried out by reviewing the validity of boundary conditions and physical properties, 3D modeling, grid generation, construction of analysis models, model validity, analysis according to frequency changes, and analysis according to physical properties. First, through the comparison of two-point support, three-point support, and two-point and three-point support in the constraint conditions, We would like to compare it with the actual molded product in the horizontal direction. But first of all, it is considered two-point support in the constraint conditions in this paper.
        4,300원
        3.
        2023.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Since 1997, the Republic of Korea (ROK) has been developing pyro-processing (Pyro) technology to reduce the disposal burden of high-level radioactive waste by recycling spent nuclear fuel (SNF). Compared to plutonium and uranium extraction process, Korean Pyro technology has relatively excellent proliferation resistance that cannot separate pure plutonium owing to its intrinsic characteristics. Regarding Pyro technology development of ROK, the Bush administration considered that Pyro is not reprocessing under the Global Nuclear Energy Partnership, whereas the Obama administration considered that Pyro is subject to reprocessing. However, the Bush and Obama administrations did not allow ROK to conduct full Pyro activities using SNF, even though ROK had faithfully complied with international nonproliferation obligations. This is because the US nuclear nonproliferation policy to prevent the spread of sensitive technologies, such as enrichment and reprocessing, has a strong effect on ROK, unlike Japan, on a bilateral level beyond the NPT regime for non-proliferation of nuclear weapons.
        4,500원
        4.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        반려동물은 점차 인간 삶의 중요한 동반자로 자리매김하고 있다. 이에 연구자들은 반려동물 상실과 이에 따른 애도에 주목하고 있다. 반려동물의 상실은 다른 상실과 달리 대개 그 부적응이 오래 지속되는 복합 애도로 나타나는 경우가 많다. 이러한 현상은 사람(vs. 반려동물)과의 관계가 더 중요하다는 사회적 인식에 기인하며, 이는 반려인이 자신의 상실 경험을 타인에게 제대로 이해받지 못한다고 여기게 만드는 일종의 ‘제약’으로 작용한다. 즉, 반려인의 지각된 사회적 제약은 이들의 반려동물 상실에 대한 회복을 저해하고 복합 애도를 유발하는 중요한 원인이 된다는 것이다. 따라서 본 연구는 반려동물의 죽음을 경험한 사람들을 대상으로 지각된 사회적 제약이 초기 상실 이후 적응을 방해함으로 써 그 충격이 복합 애도로 이어지는 과정을 심화시킬 것이라고 가정하였다. 연구 결과, 예상대로 지각된 사회적 제약은 상실의 충격과 복합 애도의 관계를 조절하는 것으로 나타났다. 구체적으로, 반려동물 상실 충격으로 인한 복합 애도는 사회적 제약을 크게 지각할수록 더 강하게 나타나는 경향이 있었다. 본 연구는 반려동물 상실 경험과 애도를 이해하는 데 지각된 사회적 제약이 중요한 역할을 담당함을 보여줌으로써 사회적 인식 변화 및 개선의 필요성을 제안한다.
        4,600원
        5.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper studied the problem of determining the optimal inventory level to meet the customer service target level in a situation where the customer demand for each branch of a nationwide retailer is uncertain. To this end, ISR (In-Stock Ratio) was defined as a key management indicator (KPI) that can be used from the perspective of a nationwide retailer such as Samsung, LG, or Apple that sells goods at branches nationwide. An optimization model was established to allow the retailer to minimize the total amount of inventory held at each branch while meeting the customer service target level defined as the average ISR. This paper proves that there is always an optimal solution in the model and expresses the optimal solution in a generalized form using the Karush-Kuhn-Tucker condition regardless of the shape of the probability distribution of customer demand. In addition, this paper studied the case where customer demand follows a specific probability distribution such as a normal distribution, and an expression representing the optimal inventory level for this case was derived.
        4,000원
        6.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Yam is an important tuber crop nutritionally, socio-culturally, and an income generator for many Nigerian. This explains its high demand both locally and internationally, causing increased production as Nigeria leads world production with about 45.41 million metric tons annually. The peculiarity of yam production in Nigeria entails lower yield, high cost of production, and post-harvest losses. Yam produced in Nigeria falls far below the potential crop yield, therefore, it is essential to close these yield gaps through the provision of solutions to the different constraints that hamper sustainable yam production. Despite the challenges, there is still insufficient information on the impact of policies, weeds, pests, and diseases which constitute major constraints. Nigerian farmers mostly utilize indigenous cultural approaches to manage yam production. Their goal of production is to produce yam cultivars that are suitable mainly for food products leading to the neglect of other cultivars. Few selected institutions with a yam mandate have been working on improving the production of D. rotundata and D. alata through breeding yam cultivars suitable for consumption and resilient against pests and diseases. However, more extensive studies should focus on breeding programs for yam resilient under drought and flooding, with peculiar physicochemical properties that give unique textual qualities considered in pounded yam and other yam food products. In this review paper, the significance and limitations of yam production in Nigeria and her efforts to achieve sustainable production are extensively studied.
        4,000원
        7.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to develop an algorithm to solve the user equilibrium traffic assignment problem using soft link capacity constraints. This model is used to relax the hard capacity constraints model. METHODS : In the traffic assignment model that imposes the hard capacity constraints, the well-known solution algorithms used are the augmented Lagrange multiplier method and the inner penalty function method. The major drawback of using the hard-capacity constraint model is the feasible solution issue. If the capacities in the network are not sufficient to absorb the flow from the diverged flows through the hard capacity constraints, it might result in no solution; whereas, using a soft capacity constraint model guarantees a feasible solution because the soft capacity constraint model uses the penalization of constraint violation in the objective function. In this study, the gradient projection (GP) algorithm was adapted. RESULTS : Two numerical experiments were conducted to demonstrate the features of the soft capacity constraint model and the computational performance of the solution algorithm. The results revealed that imposing the soft link capacity constraints can ensure convergence. CONCLUSIONS : The proposed model can be easily extended by considering other traffic assignment models, for e.g., non-additive traffic equilibrium problem, stochastic traffic equilibrium model, and, elastic demand traffic equilibrium problem. Furthermore, the model can exist regardless of the sufficient capacity for each O-D pair to cater to their demands.
        4,000원
        12.
        2020.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 중국 상해 및 심천 증권거래소 A-Share 상장기업 단기자금 조달구조의 결정요인을 실증적으로 분 석한다. 본 연구의 초점은 기업간신용의 차입비중에 금융경색 및 재무제약 요인이 미치는 영향을 추정하는 것이다. 본 연구에서 자금시장 전반의 금융경색을 지표하는 변수로 대출-예금금리차가 추정에 포함되었다. 개별 기업의 재무제약 변수로 기존연구를 반영하여 자산총계, Whited-Wu Index, Kaplan-Zingales Index 등이 가설검 증 변수로 추정에 포함되었다. 본 연구의 실증분석에서 중국 상해 및 심천 증권거래소 A-Share 상장기업의 단기 자금 조달구조 결정요인으로 금융경색은 기업간신용 차입비중에 부(-)의 영향을 미치는 것으로 추정되어 중국 기 업의 기업간신용 차입비중이 경기순응적, 시장순응적임을 제시한다. 재무제약은 기업간신용 차입비중에 정(+)의 영향을 미치는 것으로 추정되었으며 기업간신용이 단기자금 조달수단 중에서 “열등한 대체재”로 기능함을 시사하는 것으로 여타 국가들의 기업을 분석한 기존연구를 지지하는 분석결과가 도출되었다. 운전자본관리 측면에서는 만기일치가설을 지지하는 추정결과가 도출되었다. 본 연구는 불완전패널구조를 보이는 중국 기업의 재무데이터를 분석함에 있어서 동적패널모형을 추정하여 통계적으로 유의하고 일관성 있는 실증결과를 제시한다.
        7,000원
        15.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The model predictive controller performance of the mobile robot is set to an arbitrary value because it is difficult to select an accurate value with respect to the controller parameter. The general model predictive control uses a quadratic cost function to minimize the difference between the reference tracking error and the predicted trajectory error of the actual robot. In this study, we construct a predictive controller by transforming it into a quadratic programming problem considering velocity and acceleration constraints. The control parameters of the predictive controller, which determines the control performance of the mobile robot, are used a simple weighting matrix Q, R without the reference model matrix Ar by applying a quadratic cost function from which the reference tracking error vector is removed. Therefore, we designed the predictive controller 1 and 2 of the mobile robot considering the constraints, and optimized the controller parameters of the predictive controller using a genetic algorithm with excellent optimization capability.
        4,000원
        17.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we consider the assembly line balancing (ALB) problem which is known as an very important decision dealing with the optimal design of assembly lines. We consider ALB problems with soft constraints which are expected to be fulfilled, however they are not necessarily to be satisfied always and they are difficult to be presented in exact quantitative forms. In previous studies, most researches have dealt with hard constraints which should be satisfied at all time in ALB problems. In this study, we modify the mixed integer programming model of the problem introduced in the existing study where the problem was first considered. Based on the modified model, we propose a new algorithm using the genetic algorithm (GA). In the algorithm, new features like, a mixed initial population selection method composed of the random selection method and the elite solutions of the simple ALB problem, a fitness evaluation method based on achievement ratio are applied. In addition, we select the genetic operators and parameters which are appropriate for the soft assignment constraints through the preliminary tests. From the results of the computational experiments, it is shown that the proposed algorithm generated the solutions with the high achievement ratio of the soft constraints.
        4,300원
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