• Nuclear Engineering and Technology
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• v.45 no.6
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• pp.721-730
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• 2013

Within the framework of the ASTRID project, core design studies are being conducted by the CEA with support from AREVA and EDF. The pre-conceptual design studies are being conducted in accordance with the GEN IV reactor objectives, particularly in terms of improving safety. This involves limiting the consequences of 1) a hypothetical control rod withdrawal accident (by minimizing the core reactivity loss during the irradiation cycle), and 2) an hypothetical loss-of-flow accident (by reducing the sodium void worth). Two types of cores are being studied for the ASTRID project. The first is based on a 'large pin/small spacing wire' concept derived from the SFR V2b, while the other is based on an innovative CFV design. A distinctive feature of the CFV core is its negative sodium void worth. In 2011, the evaluation of a preliminary version (v1) of this CFV core for ASTRID underlined its potential capacity to improve the prevention of severe accidents. An improved version of the ASTRID CFV core (v2) was proposed in 2012 to comply with all the control rod withdrawal criteria, while increasing safety margins for all unprotected-loss-of-flow (ULOF) transients and improving the general design. This paper describes the CFV v2 design options and reports on the progress of the studies at the end of pre-conceptual design phase 1 concerning: - Core performance, - Intrinsic behavior during unprotected transients, - Simulation of severe accident scenarios, - Qualification requirements. The paper also specifies the open options for the materials, sub-assemblies, absorbers, and core monitoring that will continue to be studied during the conceptual design phase.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.801-809
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• 1993

This paper presents the design of an automatic propellant system model in order to improving tractive performance of tractor. The theoretical basis of automatic control , the characteristics and function of the system, and the kinematic analysis are also discussed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.59
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• pp.79-84
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• 2000

Korean industries have been tend to depending upon historical information to control risk. The other hand, foreign industries have been identify risk factors using system safety techniques to predict future risk. One agency or person could not solve the problems of total safety system for improving productivity. In order to solve those problems, the production-safety group is necessary, and safety control system must be adapted by fitting to the production flow. This paper is present the methodology of driving occupational safety programs to increase productivity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.743-749
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• 2010

This paper proposes a derating design method for improving system reliability by using a probabilistic approach. In the proposed design, the focus is upon system levels in determining derated levels of stresses such as temperature and current, unlike recent design approaches that focus on component levels. System reliability is evaluated using component reliability metrics that are given as functions of time and unknown stresses; this evaluation is based on a series system-reliability model. The variation in stress, which was not considered in previous derating designs, is introduced in the present design to account for the uncertainty in both environmental and operating conditions at the customer' hands. Optimization problems for system reliability improvement are formulated and solved using FORM to determine the best derating design. An example of a derating design for an electrical system shows the details of the proposed method and its applicability to systems design for reliability improvement.

• Advances in Computational Design
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• v.3 no.3
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• pp.233-267
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• 2018

Conventional seismic design of concentrically braced frame (CBF) structures suggests that the gusset plate connecting a steel brace to beams and/or columns should be designed as non-dissipative in earthquakes, while the steel brace members should be designed as dissipative elements. These design intentions lead to thicker and larger gusset plates in design on one hand and a potentially under-rated contribution of gusset plates in design, on the other hand. In contrast, research has shown that compact and thinner gusset plates designed in accordance with the elliptical clearance method rather than the conventional standard linear clearance method can enhance system ductility and energy dissipation capacity in concentrically braced steel frames. In order to assess the two design methods, six cyclic push-over tests on full scale models of concentric braced steel frame structures were conducted. Furthermore, a 3D finite element (FE) shell model, incorporating state-of-the-art tools and techniques in numerical simulation, was developed that successfully replicates the response of gusset plate and bracing members under fully reversed cyclic axial loading. Direct measurements from strain gauges applied to the physical models were used primarily to validate FE models, while comparisons of hysteresis load-displacement loops from physical and numerical models were used to highlight the overall performance of the FE models. The study shows the two design methods attain structural response as per the design intentions; however, the elliptical clearance method has a superiority over the standard linear method as a fact of improving detailing of the gusset plates, enhancing resisting capacity and improving deformability of a CBF structure. Considerations were proposed for improvement of guidelines for detailing gusset plates and bracing members in CBF structures.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.817-828
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• 2018

Modern software, especially web-based software, is broadly used in various fields. Most web applications employ design patterns, such as a model-view-controller (MVC) pattern and a factory pattern as development technology, so the application can have a good architecture to facilitate maintenance and productivity. A web application, however, may have defects and developers must fix the defects when a user submits bug reports. In this paper, we propose a novel approach to improving fault traceability in web application by using software revision information and software behavior model to reduce costs and effectively handle the software defect. We also provide a case study to show effectiveness of our approach.

• International Journal of Automotive Technology
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• v.8 no.4
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• pp.445-453
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• 2007

This paper presents a robust controller design approach for improving vehicle dynamic roll motion performance and guaranteeing the closed-loop system stability in spite of vehicle parameter variations resulting from aging elements, loading patterns, and driving conditions, etc. The designed controller is linear parameter-varying (LPV) in terms of the time-varying parameters; its control objective is to minimise the $H_{\infty}$ performance from the steering input to the roll angle while satisfying the closed-loop pole placement constraint such that the optimal dynamic roll motion performance is achieved and robust stability is guaranteed. The sufficient conditions for designing such a controller are given as a finite number of linear matrix inequalities (LMIs). Numerical simulation using the three-degree-of-freedom (3-DOF) yaw-roll vehicle model is presented. It shows that the designed controller can effectively improve the vehicle dynamic roll angle response during J-turn or fishhook maneuver when the vehicle's forward velocity and the roll stiffness are varied significantly.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.20-25
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• 2003

21세기 초고속 통신시스템 구축의 핵심 부품인 고정밀도의 광페룰(Fig. 1)의 수요는 획기적으로 증가할 것으로 전망된다. 전 세계 광페룰 생산량의 90% 정도를 일본에서 생산하고 있으며, 현재 국내 업체들도 일본산 가공설비를 대부분 도입하여 광페룰을 생산하고 있으나 품질 수준이나 생산량에서 아직 미미한 형편이다. 광페룰의 품질수준은 통신 품질의 향상 욕구에 따라 점점 높은 정밀도와 동심도가 요구되고 있으며 정밀도에 따른 가격의 차는 수배에 달하고 있다.(중략)

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.1
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• pp.74-81
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• 2017

The door impact beam of the side-impacted vehicle plays a key role in securing occupant safety by preventing intrusion from the impacting vehicle. Despite the low production cost, the press door impact beam has been adopted sparingly because of the strength inferiority. In this study, the design technologies of the press beam aimed at improving bending strength were investigated. First, the effect of the section shape and size was examined. Next, thickness and material strength were increased. Also, the TRB beam application was simulated by varying combined thickness. Some TRB beams with reduced weight exhibited bending strength over the strength of the pipe beam. Then, the beam with a closed center section also showed remarkably enhanced maximum bending strength.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.05a
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• pp.20-23
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• 1999

The current three-stage cold extrusion process including upsetting to produce a flange is investigated for the purpose of improvement of manufacturing process. The main goal of this study is to obtain an appropriate process sequence which can produce the required part most economically without overloading of tools and select an appropriate process for reducing manufacturing cost. The current process sequence is simulated and design criteria are examined. Based on the results of simulation of the current three-stage process, a design strategy for improving the process sequence is developed using the thick-wall pipes. Based on the results of simulation of the one-stage processes, the forming processes of a flange for improving the conventional process are proposed.