• Journal of the Korean Chemical Society
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• v.22 no.4
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• pp.229-238
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• 1978

Two methods for evaluation of the dipole moment matrix elements are developed, one using the expansion method for spherical harmonics and the other the transformation method of the dipole moment matrix elements into overlap integrals for Mulliken. The numerical values of the dipole moment matrix elements evaluated by two methods are in agreement with each other.

• Journal of Korean Society for Quality Management
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• v.42 no.4
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• pp.633-646
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• 2014

Purpose: The conventional predicted MFTBF by military standard has a wide discrepancy to that of real-world operation, which leads to overstock and increase operation cost. This paper introduces a analyzing frame using operational reliability and cost data to overcome the discrepancy, and provides reliability improvement process employing the analyzing frame. Methods: This paper suggests Reliability-Cost Matrix (R-C Matrix) and Operational Reliability & Cost Index (ORCI) as a tool for reliability evaluation. Results: KOREIP(KAI's Operational Reliability Evaluation and Improvement Process) is developed employing Reliability-Cost Matrix and Operational Reliability & Cost Index. Conclusion: KOREIP provides a process and its activities based on Reliability-Cost Matrix frame. The process and activities leads reliability improvement of aerospace electronic equipments by means of categorizing and follow-up action based on the concept of frame.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.441-457
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• 2011

In this study, the axiomatic design(AD) method is applied to construct the hierarchical structure of evaluation criteria and the AHP method is used to calculate the weights of criteria in order to develop the proposal evaluation index for the overseas weapon system purchasing projects. The common evaluation items as main categories are selected through the review of evaluation criteria from the previous works and projects, relevant regulations and defense policy, and the design matrix using fuzzy concept is established and evaluated by the expert group in each design phase to determine the independency, that is the satisfaction of decoupled or uncoupled design, for each criteria in the same hierarchy when they are derived from the main categories. The establishment of decoupled or uncoupled design matrix provides mutually exclusiveness of how small number of DPs can be accounted for FRs within the same hierarchy. The proposal evaluation index developed in this study will be used as a general proposal evaluation index for the overseas weapon system purchasing projects which there are no systematically established evaluation tools.

• Journal of the Korean Society of Systems Engineering
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• v.8 no.1
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• pp.21-28
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• 2012

Development of the system that has required performance is the most important figure and that is the key of project succeed. In order to perform that, systems engineering has come to the fore as a solution. In each step of system engineering process, particularly, requirement analysis and derivation, logical solution, architecture design step are known to affect many of the function and efficiency. Of these, this paper focus on architecture design. We introduce methodology for physical architecture design by applying DSM(Design Structure Matrix) methodology which is based on result of logical solution from MBSE methodology.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.79-83
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• 2000

Interfacial and microfailure properties of carbon liber/bismaleimide (BMI) composites were evaluated using both tensile fragmentation and compressive Broutman tests with acoustic emission (AE). Since BMI is rather difficult matrix to apply for the conventional fragmentation test because of its too low elongation and too brittle and high modulus properties, dual matrix composite system was applied. After carbon fiber/BMI composite was prepared for rod shape by controlling differing curing stage, composites rod was embedded in toughened epoxy as outer matrix. The typical microfailure modes including fiber break, matrix cracking, and interlayer failure were observed during tensile testing, whereas the diagonal slippage in fiber ends was observed during compressive test. On the other hand, AE amplitudes of BMI matrix fracture were higher than carbon fiber tincture under tensile test because BMI matrix has very brittle and high modulus. The waveform of signals coming from BMI matrix fractures was consistent with AE amplitude result under tensile tests.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.10
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• pp.539-545
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• 2004

In this paper, we consider the problem of capacitance matrix calculation for strip-line and other interconnects crossings. The problem is formulated in the spectral domain using the method of moments. Sinc-functions are employed as basis functions. Conventionally, such a formulation leads to a large, non-sparse system of linear equations in which the calculation of each of the coefficient requires the evaluation of a Fourier-Bessel integral. Such calculations are computationally very intensive. In the method proposed here, we provide simplified expressions for the coefficients in the moment method matrix. Using these simplified expressions, the coefficients can be calculated very efficiently. This leads to a fast evaluation of the capacitance matrix of the structure. Computer simulations are provided illustrating the validity of the method proposed.

• Proceedings of the CALSEC Conference
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• 1999.07b
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• pp.491-500
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• 1999

Recent increase of commercial network Integration to World Wide Web(WWW) shifts an ordinary commerce to electronic environment. This draws more people to examine re-assurance of their secure transaction. This study investigates current status of security methodology for Electronic Payment System and extracts important axis of security level for electronic payment. Using these axis as security evaluation criteria, the research proposes a security matrix which consists of four different level of security granularity, hence allowing evaluation of a nation-wide credit card based payment system. Feasible usage of this matrix contributes to security analysis of the electronic system as whole, hence providing better secured electronic environment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.11 s.242
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• pp.1480-1487
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• 2005

Metal matrix composites(MMCs) have been rapidly becoming one of the strongest candidates for structural materials fur many high temperature application. However, among the various high temperature environments in which metal matrix composites was applied, thermal shock is known to cause significant degradation in most MMC system. Due to the appreciable difference in coefficient of thermal expansion(CTE) between reinforcement and metal matrix, internal stresses are generated following temperature changes. Infernal stresses affect degradation of mechanical properties of MMC by causing microscopic damage in interface and matrix during thermal cycling. Therefore, the nondestructive evaluation on thermal shock damage behavior of SiC/A16061 composite has been carried out using ultrasonics. For this study, SiC fiber reinforced metal matrix composite specimens fabricated by a squeeze casting technique were thermally cycled in the temperature range 298$\~$673 K up to 1000cyc1es. Three point bending test was conducted to investigate the efffct of thermal shock damage on mechanical properties. The relationship between thermal shock damage behavior and the propagation characteristics of surface wave and SH-ultrasonic wave was discussed by considering the result of SEM observation of fracture surface.

• The Korean Journal of Ecology
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• v.20 no.5
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• pp.303-313
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• 1997

A new evaluation technique, i.e. multicriterion matrix technique, on the vegetation assessment was proposed and compared with several techniques having been previously used in the environmental impact assessment. Four criterias and 10 subcriterias were selected for two evaluation indices such as vegetation naturalness value and vegetation class. These criterias were characterized by syntaxonomical informations of hemeroby concept and potential vegetation, hierarchical system between criterias, and ordinal scale of vegetation naturalness valuse. Vegetation naturalness values were classified into 11 ordinal levels and condensed to five vegetation classes for facilitating practical use. In the example study two sites were compared by using two indices. This technique could have useful applications for ssessment of regional vegetation. A vegetation map of naturalness described by combination of two indices was proposed in order to illustrate regional vegetation naturalness.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.190-194
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• 2003

Two different types of nondestructive evaluation (NDE) techniques were employed to investigate the tensile behavior of ceramic matrix composites (CMCs). Two NDE methods, ultrasonic testing (UT) and infrared (IR) thermography, were used to assess defects and/or damage evolution before and during mechanical testing. Prior to tensile testing, a UTC-scan and a xenon flash method were performed to obtain initial defect information in light of UT C-scans and thermal diffusivity maps, respectively. An IR camera was used for in-situ monitoring of progressive damages. The IR camera measured temperature changes during tensile testing. This paper has presented the feasibility of using NDE techniques to interpret structural performance of CMCs.