• 대한기계학회논문집A
• /
• 제21권1호
• /
• pp.164-172
• /
• 1997

Two parameter technique that uses far-field stress and displacement distributions was applied to composite laminates in order to calculate mode II energy release rate, $G_{II}$ . The $G_{II}$ calculated by two parameter technique was compared with that calculated from the crack closure method to inspect the effectiveness of two parameter technique. Sensitivity study of two parameter technique to the crack extension size was also performed. The results showed that both methods produced comparable $G_{II}$ results. In particular, it was found that although the crack closure method was affected by the crack extension size, the two parameter technique was less affected by the crack extension size.

• 한국안광학회지
• /
• 제8권1호
• /
• pp.53-57
• /
• 2003

5분 간격으로 착색시간을 증가시켜 R, G, Y, B칼라렌즈를 제작하였다. 색 좌표 분석은 분광측색계와 CIE $L^*a^*b^*$ color system를 사용하였다. 착색 시간에 따른 색좌표 이동 형태는 $b^*(Y-B)={\beta}a^*+{\alpha}$이며, 거의 선형적으로 변하였다. 적색의 경우 착색시간이 길수록 $G{\rightarrow}R$, $B{\rightarrow}Y$ 형태로 이동하고, Parameter ${\alpha}$, ${\beta}$ 값은 각각 -3.49, 0.90을 얻었다. 녹색의 경우 색좌표 이동은 $R{\rightarrow}G$, $B{\rightarrow}Y$ 형태이다. 10분의 착색 시간에서 가장 순수한 녹색 칼라를 얻었다. Parameter ${\alpha}$, ${\beta}$값은 각각 -0.72, -0.55을 얻었다. 황색과 청색의 경우 모두 착색 시간이 길수록 순수한 색이 된다. 황색에서 Parameter ${\alpha}$, ${\beta}$값은 각각 14.11, 1.58이고, 청색에서 Parameter ${\alpha}$, ${\beta}$값은 각각 -11.62, 1.30을 얻었다.

• 열처리공학회지
• /
• 제7권3호
• /
• pp.155-159
• /
• 1994

As Cr-Mo-V steels have excellent mechanical and creep properties at elevated temperatures, they are extensively used in power plants. However, the steam turbine components are supposed to have suffered material degradation during long-term service at elevated tenperatures. Many efforts have been made to assess the safety and residual life of these components by means of non-destructive methods such as plastic replication, hardness and electric resistance techniques. Recently, a parameter correlating hardness changes during long-term heating to those during creep was introduced and it was named 'G parameter'. The electric resistivity as well as hardness are affected by damage accumulation, but there have been no efforts to correlate G parameter to resistivity changes. In this study, relationship between G parameter and changes in electric resistivity was investigated using artificially aged Cr-Mo-V steel. It is well understood that G parameter can be applied to electric: resistance techmique.

• 한국주조공학회지
• /
• 제29권4호
• /
• pp.181-186
• /
• 2009

The interrelationship between new parameter ${\sigma}$ and maximum diameter $D_{max}$ is elaborated and discussed in comparison with four other glass forming ability (GFA) parameters, i.e. (1) super-cooled liquid region ${\Delta}T_x (=T_x - T_g)$, (2) reduced glass transition temperature $T_{rg} (=T_g/T_l)$, (3) K parameter $K (=[T_x-T_g]/[T_l -T_x])$, and (4) gamma parameter ${\gamma}(=[T_x]/[T_l+T_g])$ in Ca-based bulk metallic glass (BMG) systems. The ${\sigma}$ parameter, defined as ${\Delta}T^*{\times}P^'$, has a far better correlation with $D_{max}$ than the GFA parameters suggested so far, clearly indicating that the liquid phase stability and atomic size mismatch dominantly affect the GFA of Ca-based BMGs. Thus, it can be understood that the GFA of BMGs can be properly described by considering structural aspects for glass formation as well as thermodynamic and kinetic aspects for glass formation.

• 대한전자공학회논문지SP
• /
• 제40권6호
• /
• pp.61-70
• /
• 2003

본 논문에서는 SMV와 G.723.1 음성부호화기를 위한 파라미터 직접 변환 방식의 상호부호화 알고리듬을 제안한다. 상호부호화를 위하여 부가적인 복호화, 부호화 과정을 거쳐야하는 Tandem 방식과 달리 제안된 방식에서는 양 음성부호화기가 음성을 부호화하는데 공통적으로 사용되는 파라미터들을 직접 변환한다. 제안된 알고리듬은 파라미터 복호화, LSP 변환, 피치 지연 변환, 여기신호 변환 그리고 비트율 결정으로 이루어진다. 제안된 알고리듬을 다양한 방법으로 평가해 본 결과 계산량과 지연시간을 줄이면서 tandem 방식과 동등한 수준의 음질을 구현함을 확인할 수 있었다.

• 대한수학회지
• /
• 제43권6호
• /
• pp.1231-1252
• /
• 2006

In this paper we shall explicitly calculate the formula of the algebraic presentation of an embedding of the Teichmiiller space ${\Im}(M)$ into the Goldman space g(M). From this algebraic presentation, we shall show that the Goldman's length parameter on g(M) is an isometric extension of the Fenchel-Nielsen's length parameter on ${\Im}(M)$.

• 전력전자학회논문지
• /
• 제23권5호
• /
• pp.321-327
• /
• 2018

DC microgrid system composed of multiple converters has a tendency to make the system unstable due to the interaction of converters. To solve this problem, in this paper, the interaction between cascaded converters with LC input filter is analyzed with impedance modeling using g-parameter. The input impedance and the output impedance of the system can be obtained through this technique. The stability of the system can be determined by applying Middlebrook's stability criterion to the impedance. Virtual impedance is added to the controller to enhance stability. The validity of the analysis is verified by the result of several simulations and experiments.

• Kyungpook Mathematical Journal
• /
• 제55권4호
• /
• pp.983-996
• /
• 2015

In the paper A new parameter for Ramanujan's theta-functions and explicit values, Arab J. Math. Sc., 18 (2012), 105-119, Saikia studied the parameter $A_{k,n}$ involving Ramanujan's theta-functions ${\phi}(q)$ and ${\psi}(q)$ for any positive real numbers k and n and applied it to find explicit values of ${\psi}(q)$. As more application to the parameter $A_{k,n}$, in this paper we prove a new general theorem for explicit evaluation of Ramanujan-$G{\ddot{o}}llnitz$-Gordon continued fraction K(q) in terms of the parameter $A_{k,n}$ and give examples. We also find some new explicit values of the parameter $A_{k,n}$ and offer reciprocity theorems for the continued fraction K(q).

• 한국물환경학회지
• /
• 제27권3호
• /
• pp.364-370
• /
• 2011

Water quality criteria for human health protection are derived based on the human health risk assessment. Water quality criteria in Korean freshwater bodies have been derived according to the equations developed by the US Environmental Protection Agency. The equations include the fish intake parameter, which is very important factor that significantly influences on the criteria derivation. So far, several fish intake values were used in human health risk assessment for water quality standards and effluent standards. However, these values are not consistent and they refer to various sources. Therefore, there is a need to suggest the most appropriate value of fish intake parameter to derive freshwater quality criteria in Korea. In this study, national and international fish intake values were widely collected and evaluated to select the adequate value of fish intake parameter that can be applied in Korea. The USEPA presented fish intake parameter as the 17.5 g/day for general adults and sport fishers and 142.4 g/day for subsistence fishers. In Korean reports, wide range values of 2 to 67.7 g/day were suggested as fish intake value. These values included finfish and shellfish intakes in common but had various habits. This study found that the 52.4 g/day suggested in Korean Exposure Factors Handbook published by the Ministry of Environment in 2007 seemed to be the suitable fish intake parameter to derive the freshwater quality criteria in Korea. The value is based on water corrected intakes of finfish and shellfish present in freshwater and coastal areas. We expect that this report can be useful to select suitable fish intake value in human health risk assessment for establishing freshwater quality standard in Korea.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제8권2호
• /
• pp.51-73
• /
• 2004

A boundary layer analysis is used to study the effects of Hall and ion-slip currents on the steady magneto-micropolar of a viscous incompressible and electrically conducting fluid over a horizontal plate. By means of similarity solutions, deviation of fundamental equations on the assumption of small magnetic Reynolds number are solved numerically by using the shooting method. The effects of various parameters of the problem, e.g. the magnetic parameter, Hall parameter, ion-slip parameter, buoyancy parameter and material parameter are discussed and shown graphically.