• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.11 s.116
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• pp.1132-1139
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• 2006

Non-contact underwater explosions against surface ship could cause extensive equipment damage during wartime service. Thus, the need to develop methods for the design of shock resistant equipment structures and systems was strongly established. In analytical methods, DDAM(Dynamic Design and Analysis Method) and transient repsonse method are used for ship shock design. In this paper, to analyze the characteristics of DDAM, medium weight shock test, DDAM and transient response analysis for missile system equipment are performed.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.309-314
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• 2007

Recently, the LRFD and the PSF based on structural reliability assessment have been applied to NPP designs in behalf of the conventional deterministic design methods. In the risk-informed structural integrity, it is especially possible to optimize design procedures considering cost, manufacturing and maintenance because the structural reliability concepts have confirmed the reliability for which a designer aims. Generally, in order to evaluate the PSF, the LRFD which is the design concept for evaluating safety factors respectively on the limit state function including load and resistance. This study certifies the concept and its applications of the PSF using the LRFD based on the structural reliability engineering.

• Wind and Structures
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• v.37 no.2
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• pp.117-131
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• 2023

Korea Design Standard (KDS) will be updated with two major revisions on the assessment of wind load and performance-based wind design (PBWD). Major changes on the wind load assessment are the wind load factor and basic wind speed. Wind load factor in KDS is reduced from 1.3 to 1, and mean recurrence interval (MRI) for basic wind speed increases from 100 years to 500 years considering the reduction of wind load factor. Additional modification is made including pressure coefficient, torsional moment coefficient and spectrum, and aeroelastic instability. Combined effect of the updates of KDS code on the assessment of wind load is discussed with the case study on the specified sites and building. PBWD is newly added in KDS code to consider the cases with various target performance, vortex-induced vibration, aeroelastic instability, or inelastic behavior. Proposed methods and target performance for PBWD in KDS code are introduced.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1636-1640
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• 2011

To consider dynamic magnification effect at the static design stage, impact factor is applied to design load. Current impact factor adopted EUROCODE without domestic verification through theoretical and experimental studies. This study evaluated impact factor of railway bridges from dynamic response under KTX running. Moving Average Method was applied to calculate impact factor. Investigation considering different type of bridges and tracks including velocity was conducted.

• Journal of the Korean Data and Information Science Society
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• v.18 no.2
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• pp.525-534
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• 2007

It is a common practice in many research areas that multiple range tests for a between subject factor such as Tukey are applied to a within subject factor in a repeated measures design. Tukey procedure, however, sometimes detects no pairs with different means even when the hypothesis of all equal level means is rejected. This study attempts to provide a rationale for the proposition that Tukey is inappropriate post hoc procedure for a within subject factor in which the observations are correlated. We introduce two multiple range tests, Bonferroni and Scheffe, for a within subject factor and show that Bonferroni is more appropriate than Scheffe for pairwise multiple comparisons. Subsequent simulation study indicates that Tukey has significantly less power than Bonferroni in detecting actual difference between means of some pairs when the observations of a within subject factor are highly correlated.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.2
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• pp.161-166
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• 2004

The impact factor of bridges is analyzed based on experimental data to examine the characteristics of the dynamic responses of bridges. The experimental impact factors are compared with the impact factor of Korean Highway Design Specification and Japan T-load in terms of the span length. According to the superstructural types of bridges, the variation of the impact factor is analyzed. When vehicles are passing on a bridge, the dynamic effect acts on the bridge impact factor more than at the time of design because of the velocity of vehicles, the surface roughness reduction due to the deterioration of the bridge deck pavement, and the disconnection of the bridge entrance and the expansion joint. Because the actual value is greater than the expected value at the time of design, the dynamic response of the bridge accelerates the deterioration of the bridge due to the accumulation of fatigue, and the bridge's life-time is shortened and can have an influence on the serviceability and safety of the bridge.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.10a
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• pp.201-208
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• 1997

In most seismic codes such as the Uniform Building Code(UBC), the response modification factor(or the force reduction factor)is used to reflect the capability of a structure in dissipating energy through inelastic behavior. The response modification factor is assigned according to structural system type. Ductile systems such as special moment-resisting steel frames are assigned larger values of the response modification factor, and are consequently designed for smaller seismic design forces. Therefore, structural damage may occur during a severe earthquake. To ensure safety of the structures, the suitability of the response modification factor used in aseismic design procedures shall be evaluated. The object of this study is to develop a method for the evaluating of the response modification factor. The validity of the evaluating method has been examined for several cases of different structures and different earthquake excitations.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.388-390
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• 1999

This paper discusses an optimal design of high space factor BLDC motor. Because of high space factor BLDC, Nonliear finite element method considering saturation of outer-rotor is used. For optimal design, a new niching genetic algorithm, namely "Restricted Competitions Selection" is used. This algorithm constructs an objective function using only the most important criteria and provides a designer with a set of solution rather than one solution. To verify its effectiveness, the new niching genetic algorithm is applied to an actual high space factor BLDC motor We show that a new designed high space factor BLDC motor is superior to the actual high space factor BLDC.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.20-25
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• 2008

Codebook-based opportunistic beamforming (COBF) technique provides a beam selection diversity to the conventional opportunistic beamforming. In this paper, we design the random matrix and codebook for the COBF technique based on a kappa-factor channel model. Applying the proposed design to the COBF, nearly optimal beams are generated. Therefore, the COBF shows an outstanding performance without regard to the channel correlation related to the kappa-factor.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1179-1182
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• 2005

Nowadays, CRTs are threatened by the flat panel displays (FPD). The screen quality of the CRT is one of best among the displays, however, the depth of CRTs becomes one of the most important design factor to maintain the dominated portion in the display market. When designing slim CRTs, the structure of the glass is important design factor because of the weight and safety. The stress in the glass is increased according to the shortening the total length of tube. The residual stress of the seal is also a major factor should be considered due to the large seal edge thickness. The glass design concept for Vixlim is introduced in this paper.