• Journal of Digital Convergence
• /
• v.16 no.6
• /
• pp.205-212
• /
• 2018

This Study aims to propose a new information security governance model design method for streamlining security governance at national strategic level. The research method of this study is to diagnose our operational experience and to derive a new model design method. In the meantime, national information security activities were perceived to be focused on knowledge transfer, and motivation of activities and securing of executive power were weak. As a result, security blind spots and frequent occurrence of large security incidents have become unresolved challenges. National cyber security governance should be grouped together as a whole systematically from the upper policy to the lower level of performance under the responsibility of the national leader. Based on this approach, this study presented the comprehensive framework of Korean security governance model and embodied it into four architectural designs such as vision, goal, process, and performance, thus deriving the foundation for future national governance model design. Further research is needed to diagnose problems in life cycle flow, security policies based on environmental changes, and new frameworks in which all subjects participate.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.14 no.2
• /
• pp.1-13
• /
• 2010

This paper proposes an optimal design method for the nonlinear seismic isolated bridge. The probabilities of failure at the pier and the seismic isolator are considered as objective functions for optimal design, and a multi-objective optimization technique is employed to efficiently explore a set of multiple solutions optimizing mutually-conflicting objective functions at the same time. In addition, a stochastic linearization method is incorporated into the multi-objective optimization framework in order to effectively estimate the stochastic responses of the bridge without performing numerous nonlinear time history analyses during the optimization process. As a numerical example to demonstrate the efficiency of the proposed method, the Nam-Han river bridge is taken into account, and the proposed method and the existing life-cycle-cost based design method are both applied for the purpose of comparing their seismic performances. The comparative results demonstrate that the proposed method not only shows better seismic performance but also is more economical than the existing cost-based design method. The proposed method is also proven to guarantee improved performance under variations in seismic intensity, in bandwidth and in the predominant frequency of the seismic event.

• Korean Journal of Construction Engineering and Management
• /
• v.14 no.1
• /
• pp.115-123
• /
• 2013

Changes have occurred in the professional capabilities of the construction project managers after the global financial crisis. As representatives of construction companies and projects, construction project managers have full responsibility over a construction project. Throughout its life cycle, from design through construction to completion, the business capabilities of such managers are regarded as critical elements in the changes in the country's construction economy. Therefore, this study aimed to determine the main capabilities of current construction project managers, and to analysis of its competitiveness using Important-Performance Analysis(IPA). The results of IPA were as follows; (1)capability to win new contracts and capability to collect information of new project are needed for external relation competitiveness, (2)gerentocratic management mind-set and active breakthrough are needed for internal project management competitiveness, and (3)capability to predict issues and self-improvement are needed for self discipline competitiveness. However, this work is still considered to provide the basic data that can help Korean construction companies who plan to educate the project manager's strengthen their medium and long-term capabilities.

• Journal of Hydrogen and New Energy
• /
• v.16 no.2
• /
• pp.170-179
• /
• 2005

Electrolyte loss is considered as one of the major obstacles limiting the life time of molten carbonate fuel cells (MCFCs). Unit cells with an effective area of 100 $cm^2$ were prepared and were operated to determine the optimum matrix thickness which contains the maximum amount of electrolyte without serious preformance loss caused by high resistance. Matrices with different thickness, 1.45, 1.8, and 2.3 mm, were used in unit cells and those cells were operared about 5000, 10000, and 4000 hrs. The unit cell used 1.8 mm thick matrix showed 0.85 V (at 150 mA/$cm^2$) as the intial performance and this cell voltage is not lower than the cell voltage obtained in the cell with 1 mm thick matrix. This cell was operated for 10000 hrs. The cell used 1.45 mm thick matrices showed 16.6 % in the electrolyte loss after 5000 hr operation. In the case of the cell with 2.3 mm thick matrix, the initial cell voltage was below 0.80 V (at 150 mA/$cm^2$). For thermal cycle test, the gas crossover amount of unit cell used 1.8 mm thick matrix was much less than that of the cell with 1.0 mm thick matrix.

• Journal of Hydrogen and New Energy
• /
• v.29 no.2
• /
• pp.212-218
• /
• 2018

Li-ion battery system is regarded as one of the most potent power sources for electrified power-trains. For the Li-ion battery system to be widely adopted in automotive applications, the performance, safety, and cycle life issues need to be properly addressed. These issues are closely related to the thermal management of battery system. Especially, the effective cooling module design is the core part for the novel battery thermal management system development. In this paper, an experimental approach was carried out as a basic part of comprehensive battery thermal management research. The main goal of this paper is to present a comparison of two cooling systems (air cooling and phase change material (PCM) based cooling) of the unit 18650 battery module. The temperature rise with different battery discharge rate (c-rate) was mainly investigated and analyzed for two types of battery cooling systems. It is expected that this study can properly contribute to providing basic insights into the design of robust battery thermal management system for vehicular applications.

• Journal of Internet Computing and Services
• /
• v.21 no.2
• /
• pp.131-138
• /
• 2020

The SBA Integrated Information system is constructed and operated for scientific and systematic management of Defense information utilizing whole process of weapon system acquisition from requirement institution to operation maintenance. In order to utilize m&s resources actively and effectively in the life cycle of weapon system acquisition, efficient management plans of the SBA integrated Information system is required. As a result of identifying usage on SBA Information system and performance of operation performance measurement, it was defined that establishment of the SBA Integrated Information system process and provision of detailed system are mandatory for activating m&s resource and supporting process of acquisitions. In this study, Defense m&s information system is analyzed and improvement plans of SBA Integrated Information system is provided for efficient operation of SBA integrated Information system.

• Journal of Electrochemical Science and Technology
• /
• v.5 no.1
• /
• pp.1-18
• /
• 2014

Li-air cell is an exotic type of energy storage and conversion device considered to be half battery and half fuel cell. Its successful commercialization highly depends on the timely development of key components. Among these key components, the catalyst (i.e., the core portion of the air electrode) is of critical importance and of the upmost priority. Indeed, it is expected that these catalysts will have a direct and dramatic impact on the Li-air cell's performance by reducing overpotentials, as well as by enhancing the overall capacity and cycle life of Li-air cells. Unfortunately, the technological advancement related to catalysts is sluggish at present. Based on the insights gained from this review, this sluggishness is due to challenges in both the commercialization of the catalyst, and the fundamental studies pertaining to its development. Challenges in the commercialization of the catalyst can be summarized as 1) the identification of superior materials for Li-air cell catalysts, 2) the development of fundamental, material-based assessments for potential catalyst materials, 3) the achievement of a reduction in both cost and time concerning the design of the Li-air cell catalysts. As for the challenges concerning the fundamental studies of Li-air cell catalysts, they are 1) the development of experimental techniques for determining both the nano and micro structure of catalysts, 2) the attainment of both repeatable and verifiable experimental characteristics of catalyst degradation, 3) the development of the predictive capability pertaining to the performance of the catalyst using fundamental material properties. Therefore, under the current circumstances, it is going to be an extremely daunting task to develop appropriate catalysts for the commercialization of Li-air batteries; at least within the foreseeable future. Regardless, nano materials are expected to play a crucial role in this field.

• Journal of Electrochemical Science and Technology
• /
• v.9 no.3
• /
• pp.220-228
• /
• 2018

This study introduced a carbon-free electrode for $Li-O_2$ cells with the aim of suppressing the side reactions activated by carbon material. Micro-particles of poly(3,4-ethylenedioxythiophene) (PEDOT), a conducting polymer, were used as the base material for the air electrode of $Li-O_2$cells. The PEDOT micro-particles were treated with $H_2SO_4$ to improve their electronic conductivity, and LiBr and CsBr were used as the redox mediators to facilitate the dissociation of there action products in the electrode and reduce the over-potential of the $Li-O_2$ cells. The capacity of the electrode employing PEDOT micro-particles was significantly enhanced via $H_2SO_4$ treatment, which is attributed to the increased electronic conductivity. The considerable capacity enhancement and relatively low over-potential of the electrode employing $H_2SO_4$-treated PEDOT micro-particles indicate that the treated PEDOT micro-particles can act as reaction sites and provide storage space for the reaction products. The cyclic performance of the electrode employing $H_2SO_4$-treated PEDOT micro-particles was superior to that of a carbon electrode. The results of the Fourier-transform infrared spectroscopic analysis showed that the accumulation of residual reaction products during cycling was significantly reduced by introducing the carbon-free electrode based on $H_2SO_4$-treated PEDOT micro-particles, compared with that of the carbon electrode. The cycle life was improved owing to the effect of the redox mediators. The refore, the use of the carbon -free electrode combined with redox mediators could realize excellent cyclic performance and low over-potential simultaneously.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.7 s.178
• /
• pp.1779-1786
• /
• 2000

Most of traditional design processes of mechanical parts are regarded as sequential and discrete, since different kinds of softwas should be introduced. In this paper, we develop an integrated fram ework for virtual design and performance testing of an automobile seat. The system is composed of four modules, i.e. CAD, static analysis, dynamic analysis, and draft drawing module. In the CAD module, PRO/ENGINEER 3D seat model is created using parameters to be modified with the result of static and dynamic analysis. In the static analysis, headrest tere used in each design stage make it difficult to feedback their results to upstream process. These discrete processes may result in time loss and cost rise. In recent years, life cycle of product is reduced. To have competence with others, new concept design processt is simulated using ANSYS. In the dynamic analysis module, FMVSS201 test is simulated using DADS. Overall data flow is controlled by Motif. The advantage of the system is that even a novice can perform and review the whole design process, without a good hand at professional design/analysis S/W in each stage. The system also provides a virtual design space, where engineers in different development stage can access common data of design models. The concept could be applied to other fields and it could reduce time and money required in design process.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.1
• /
• pp.92-100
• /
• 2016

Many research efforts have made on various fields to develop a system which is able to process diverse data in terms of efficiency and accuracy as well as minimizing the error in data-processing. As known, it is obvious that procurement is crucial process for the plant projects due to its importance and impact on the performance. It is strongly required to develop an effective metadata system to assist optimal controlling data for the logistics discipline of procurement processes in plant projects. Therefore, the main purpose of this paper is to apply a metadata system for logistics of the plant projects. The suggested technical module is tested using sample data and evaluated its performance in terms of accuracy and running speed. The results of this research will be extended to the other processes of plant projects in order to achieve a ultimately process-based life-cycle plant project information management system