• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2005.05a
• /
• pp.983-989
• /
• 2005

Secondary batteries with high performance are essential in widespread use of modern portable devices such as cellular phones and laptop computers. High energy density, long cycle life, and safety are some of important requirements for secondary battery. To achieve such characteristics, a mixing proportion of electrolyte solution ingredients in the battery should be carefully chosen. In this paper, using statistical design of mixture experiments (DOME), we attempt to find an optimum condition of designing the secondary battery. DOME has a distinct feature in that the experimental region is represented by simplex, rather than hypercube, because the sum of blend proportions should be unity. Several designs based upon this point have been proposed for mixture experiments. Among them, an extreme vertices design is employed in this paper because there are a couple of blend constraints to be considered. In order to investigate how the mixing proportion interacts with other manufacturing factors, a fractional factorial design is also included across the extreme vertices design. As a result, we find that the blend proportion of solution ingredients has a significant effect on battery performances. By simultaneously optimizing two battery capacities, this paper proposes an optimum blend proportion according to process factor settings.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.4 no.1
• /
• pp.246-254
• /
• 2001

The breech system can be considered as a pressure vessel with an internal plug under high explosive pressure. The system consists of a breech block(internal plug) whose front surface subjects to pressure, and a breech ring(pressure vessel). There is the geometric discontinuity around roots of connection parts and then stress concentration is introduced due to pressure, where contact effect may be ignored because contact plane between two equipments is parallel ideally, Generally high stress concentration phenomena shorten the life cycle of the mechanical system. It is well known that shock load is much more harmful on safety of the system than static load. In this present paper, several geometric design variables which may affect stress condition on the system are chosen and the parametric study on the design variables is carried using commercial FEM codes. Finally, the obtained results in the single lug breech system are applied to design the 3 lugs breech system. The 3 lugs breech system can reduce the maximum stress level.

• IE interfaces
• /
• v.18 no.4
• /
• pp.402-411
• /
• 2005

Secondary batteries with high performance are essential in widespread use of modern portable devices such as cellular phones and laptop computers. High energy density, long cycle life, and safety are some of important requirements for secondary battery. To achieve such characteristics, a mixing proportion of electrolyte solution ingredients in the battery should be carefully chosen. In this paper, using statistical design of mixture experiments (DOME), we attempt to find an optimum condition of designing the secondary battery. DOME has a distinct feature in that the experimental region is represented by simplex, rather than hypercube, because the sum of blend proportions should be unity. Several designs based upon this point have been proposed for mixture experiments. Among them, an extreme vertices design is employed in this paper because there are a couple of blend constraints to be considered. In order to investigate how the mixing proportion interacts with other manufacturing factors, a fractional factorial design is also included across the extreme vertices design. As a result, we find that the blend proportion of solution ingredients has a significant effect on battery performances. By simultaneously optimizing two battery capacities, this paper proposes an optimum blend proportion according to process factor settings.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.6
• /
• pp.930-937
• /
• 2003

The extension of design life among power plants is increasingly becoming a world-wide trend. Kori #1 unit in Korea is operating two cycle. It has two man-ways for tube inspection in a steam generator which is one of the important components in a nuclear power plant. Especially, stud bolts fur man-way cover have damaged by disassembly and assembly several times and degradation for bolt materials for long term operation. It should be evaluated and compared by ASME Code criteria for integrity evaluation. Integrity evaluation criteria which has been made by the manufacturer is not applied on the stud bolts of nuclear pressure vessels directly because it is controlled by the yield stress of ASME Code. It can apply evaluation criteria through FEM analysis to damaged female threads and to evaluated safety fer helical-coil method which is used according to Code Case-N-496-1. From analysis results, we found .that it is the same results between stress intensity which got from FEM analysis on damaged female threads over 10％ by manufacture integrity criteria and 2／3 yield strength criteria on ASME Code. It was also confirmed that the helical-coil repair method would be safe.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1129-1137
• /
• 2007

50kg NSI PCT(Prestress Concrete Timber, sleeper) is developed for the purpose of low maintenance cost, Extend life cycle, Track stability, Friendly Environment, Good running quality. In this study, as a part of research which is to make renovated NSI turnout, the main objective of this study is the optimization of PC sleeper's section, the number of PS tension wire. For this purpose, the finite element analysis was conducted to evaluate the serviceability and the safety of NSI PC sleeper developed.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.51-56
• /
• 2007

Pantograph of the electric train is the important part receiving current by adhereing contact wire. Wearing rate of pantograph or contact wire is changed by the type of pantograph and material of adhering part. In special, the weather influences the relative wearing rate and wearing type of pantograph Slider and Contact wire with steep wearing in arc and life cycle of pantograph slider. Presently, the weather causes side-wearing and over-wearing of pantograph slide installed in electric train. So it is difficult to manage and operate the electric train. Although the quality of slide using in line4 vehicle was finished the test in line 2 vehicle experimentally, it has to apply after pantograph is installed in some electric trains and check the influence in it and contact wire. It is because line4 section is very different from line2 section. Experimental application is the sequence to certify the safety and abrasion resistance importantly by enlarging experimental application with increase of the experimental electric train. The lenth of line4 in Seoul Metro is 71.5[km]. It is long section. The line is mixed DC 1,500[V] section and AC 25,000[V] section. It has underground section of 41.5[km] and ground section of 30[km]. Ground section is about 42% and receives much influence in the rain during the rainy season. After experimental application we found that this pantograph slide has twice as much abrasion resistance despite a little deviation and found the occurrence probability of arc and side-wearing is decreased considerably.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.35 no.2
• /
• pp.212-219
• /
• 2012

This study focus on what methods of MOT are needed and utilized to solve a technical problem in the MOT leading company. We first classified the MOT methods by project life cycle and R&D job quality based on the several discussion with working group. In order to study, the survey was carried out by 168 experts working on MOT practices. Our main research findings are as follows. The level of utilized MOT methods was above average because MOT sector was beginning to represent an increasing share of total R&D business. But the satisfaction level on the MOT majors was below average. The more utilized MOT methods in practices were 'environment analysis and opportunity research,' 'business feasibility,' 'roadmapping,' 'portfolio,' 'technology tree,' 'scheduling,' 'risk management,' 'six sigma,' 'design of experiment,' 'quality control,' 'cost analysis' etc. And the subjects of product realization process were also needed to MOT practice such as 'design for reliability,' 'design for cost,' 'design for performance,' 'design for safety' deeply involved to product quality. Finally, the capability requested to University students were 'problem define and solving,' 'technology planning and strategy,' 'creative thinking.'

• Journal of the Korean housing association
• /
• v.27 no.5
• /
• pp.65-72
• /
• 2016

The purpose of the study was to investigate defect cases in residential interior design, to identify the state of defects, and to categorize types of defect and disputes. In addition, consumer appraisal to residential interior design service were analyzed. The results of this study could provide fundamental information regarding the defects and claims in residential interior design. First, we did literature review for defect disputes in architectural design and interior design. We identify the definition of defects by building life cycle, by state of construction, by activity, and by design performance. Second, we analysed interior design defects cases reported in Korea Consumer Agency & Ministry of Land, Infrastructure and Transport. A total of 49 cases of defect disputes in residential interior design from 2000 to 2015 were investigated. As a result, many defects appeared during the construction stage. A majority of defects cases fall into insulation, water-proofing/leakage work. In terms of design aspects claim, functional and aesthetic defects were claimed. Third, from Consumer Market Evaluation Indicators, raw data from 500 respondents were investigated for the housing repair and interior design. It is found that information comparability, responsiveness to consumer claim, price, and safety are important factors for consumer satisfaction in interior design.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.17-22
• /
• 2009

Reliability analyses were performed to quantify the risk in axially loaded large-scale pile foundations in consideration of pile-soil interaction and uncertainties on various design variables. The finite difference method based on an equivalent soil spring model and a load transfer method and Monte Carlo simulation method are integrated in the framework of reliabilty analysis. The applicability and efficiency of the proposed method in the safety assessment of axially loaded pile-soil system was verified using a realistic example. Since the proposed method can explicitly consider uncertainties in various design variables, and quantify failure probability of a pile foundation, it can be used to estimate risk, to obtain basic informations for life cycle cost analysis, and to develop code requirements for a reliability-based design of pile foundations.

• Earthquakes and Structures
• /
• v.9 no.6
• /
• pp.1337-1353
• /
• 2015

Seismic upgrading of existing structures is a technical and social issue aimed at risk reduction. Sustainable design is one of the most important challenges in any structural project. Nowadays, many retrofit strategies are feasible and several traditional and innovative options are available to engineers. Basically, the design strategy can lead to increase structural ductility, strength, or both of them, but also stiffness regulation and supplemental damping are possible strategies to reduce seismic vulnerability. Each design solution has different technical and economical performances. In this paper, four different design solutions are presented for the retrofit of an existing RC frame with poor concrete quality and inadequate reinforcement detailing. The considered solutions are based on FRP wrapping of the existing structural elements or alternatively on new RC shear walls introduction. This paper shows the comparison among the considered design strategies in order to select the suitable solution, which reaches the compromise between the obtained safety level and costs during the life-cycle of the building. Each solution is worked out by considering three different levels of seismic demand. The structural capacity of the considered retrofit solutions is assessed with nonlinear static analysis and the seismic performance is evaluated with the capacity spectrum method.