• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.1 s.244
• /
• pp.42-51
• /
• 2006

An indentation method to determine equi-biaxial residual stress is proposed by examining the data from the incremental plasticity theory based finite element analyses. We first select optimal normalized-parameters, which are minimally affected by indentation depth and material properties. Numerical linear regressions of obtained data exhibit that maximum load and contact area of imprint are the main parameters measuring the residual stress. The proposed indentation approach provides a substantial enhancement in accuracy compared with the prior methods.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.551-556
• /
• 2002

High-performance concrete is defined as concrete that meets special combinations of performance and uniformity requirements that cannot always be achieved routinely using conventional constituents and normal mixing, placing, and curing practices. Ever since the term high-performance concrete was introduced into the industry, it had widely used in large-scale concrete construction that demands high-strength, high-flowability, and high-durability. To obtain such performances that cannot be obtained from conventional concrete and by the current method, a large number of trial mixes are required to select the desired combination of materials that meets special performance. In this paper, therefore, using genetic algorithm which is a global optimization technique modeled on biological evolutionary process-natural selection and natural genetics-and can be used to find a near optimal solution to a problem that may have many solutions, the new design method for high-performance concrete mixtures is suggested to reduce the number of trial mixtures with desired properties in the field test. Experimental and analytic investigations were carried out to develop the design method for high-performance concrete mixtures and to verify the proposed mix design.

• Korean Management Science Review
• /
• v.13 no.2
• /
• pp.49-59
• /
• 1996

The use of advanced electronic security system is growing quickly to protect properties and life. However, customers cannot select appropriate configuration of the system because there are no objective evaluation methods to measure the security ability of the system. Furthermore, the system suppliers cannot propose quantitative value of security ability of the system. This study suggests an objective evaluation and selection method that customers and suppliers can use to base his or her decision when choosing the most appropriate configuration of the system. Our method identifies 6 characteristics and 20 sub- characteristics of the electronic security system, calculates their weights, and decides the best configuration. We use AHP (Analytic Hierarchy Process) to assign the weights of characteristics. Finally, this paper gives an example to compare four alternative configurations of the system.

• Microbiology and Biotechnology Letters
• /
• v.31 no.3
• /
• pp.297-300
• /
• 2003

In order to select probiotics with a high survival rate in gut and the growth inhibition of virulent pathogens to human beings or animals, we have screened lactic acid bacteria and yeasts from Jeot-gal to assess resistance against the artificial gastric acid and bile juice. Lactic acid bacteria and yeasts isolated were incubated for 24 h in artificial bile juice after incubation for 2 h in artificial gastric acid. Especially, strain HW 161 and strain NK 181 showed the higher survival for 2 h incubation in artificial gastric acid. All of 3 strains of lactic acid bacteria and 2 strains of yeast were showed higher growth rate than the control in artificial bile. The antimicrobial activity of lactic acid bacteria and yeasts was also investigated to prove efficacy as probiotic organisms. Lactic acid bacteria were shown the inhibition of Gram positive and negative bacteria, but yeasts narrow inhibition.

• Korean Journal of Human Ecology
• /
• v.12 no.1
• /
• pp.63-73
• /
• 2003

The purpose of this study was to quantify the hands of fabrics for the Korean folk clothes using both a KES-FB and an artificial neural network. In order to select the proper input parameters, we calculated the correlation using step-wise regression between mechanical properties and the hand value of fabrics. For the classification, the primary hand values and total hand value, five neural networks with three-layered structure were constructed using the error back propagation algorithm and, in order to reduce errors and to speed up learning, the momentum method was selected. From the analysis of the primary and total hands using a self-constructed artificial intelligence system, the error rates of sleekness, stiffness, silkiness, and roughness compared with the judgement of expert panels were found to be 3.3%, 3.3%, 1.6%, and 4.9%, respectively, while that of the total hand was 9.83%.

• Transactions on Electrical and Electronic Materials
• /
• v.6 no.5
• /
• pp.225-228
• /
• 2005

In this work, we studied the optimized copper thickness in Cu ECP (Electrochemical Plating). In order to select an optimized Cu ECP thickness, we examined Cu ECP bulge (bump, hump or over-plating amount), Cu CMP dishing and electrical properties of via hole and line trench over dual damascene patterned wafers split into different ECP Cu thickness. In the aspect of bump and dishing, the bulge increased according as target plating thickness decreased. Dishing of edge was larger than center of wafer. Also in case of electrical property, metal line resistance distribution became broad gradually according as Cu ECP thickness decreased. In conclusion, at least $20\%$ reduced Cu ECP thickness from current baseline; $0.8\;{\mu}m$ and $1.0\;{\mu}m$ are suitable to be adopted as newly optimized Cu ECP thickness for local and intermediate layer.

• Proceedings of the KIEE Conference
• /
• 1998.11c
• /
• pp.869-871
• /
• 1998

The extensive use of composite insulators for transmission lines can ultimately be justified only on long-term qualification tests. The actual load working on the insulator in the field is not static load but cyclic load. So in this paper, we discussed an examination of aging degradation by mechanical performance of composite insulators under static tension load and cyclic tension load. and also described useful approaches for analyzing their long term performance so as to develop reliable composite insulators. The static and cyclic tension load-time test data were examined by Weibull distribution for their capability of presuming long term performance. It was found that cyclic tension loads were more severe than static tension loads. The results also indicate that it may be relevant for an user to select composite insulators on basis of their performance under cyclic tension loads than static tension loads.

• Journal of the Korean housing association
• /
• v.10 no.4
• /
• pp.83-90
• /
• 1999

This study is concerned on the decorating design and method of handrail of the old residential houses. The method of studying is proceeding to select and survey the houses identified as the cultural properties that have the value of heritage in the handrail design. The conclusion as following ; Handrail play not only functional part but embellished part. The wood Handrails can be classified in two styles ; One "pyung"(평) style, another "keja"(계자) style. The former is composed of straight lines which looks simple. On the other hand, the latter contains the elavorated decoration which gives solid beauty. In conclusion, the characteristic of the handrail in Korean structure is found in the changing the sense of the lineal and curve beauty into the symmetrical line, and is fund in the variety of the high qualified details. Over its esthetic senses, the residents'hope and need for the goodness such as good omen, rich longevity and getting boys and formed as passive symbolic world, and the auspicious signed letters and the geometric and natural forms of plants, are expressed upon the decorating design of handrail. design of handrail.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.2
• /
• pp.115-115
• /
• 2014

First, We will briefly introduce early science results of AGN observations with KVN and KaVA. KaVA is the combined array of the Korean VLBI network (KVN) and VLBI Exploration of Radio Astronomy (VERA). These include KaVA monitoring of M87, Sgr A* and a few bright blazars and KVN Search for circular polarized Blazars. Furthermore, we will present our future plan of monitoring observation of Sgr A* and M87 with KaVA and Low Radio Power AGN multi frequency polarization survey with KVN. Because of the largeness of their centralsuper-massive black holes, we select them as top-priority sources of our key science program (KSP). The main science goals of the KaVA KSP are (1) mapping the velocity field of the M87 jet and testing magnetically-driven-jet paradigm, and (2) obtaining tightest constraints on physical properties of radio emitting region in Sgr A. High sensitivity achieved through simultaneous multifrequency phase referencing technique of KVN will allow us to explore Low Radio Power AGN cores which build majority of AGNs and therefore are important for undestanding the evolution of AGNs and of their hosts.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.04a
• /
• pp.463-468
• /
• 1999

The slurry wall of Inchon LNG receiving terminal tank will be planned the super flowing concrete having properties of high strength (required strength 520kg/$\textrm{cm}^2$), no-vibrating and massive structure in the underground. For the performance of this concrete, we investigate and select all materials, the optimum mix design and sensibility test in the laboratory. As test results, we choose portland blast-furnace slag cement and lime stone powder(L.S.P) as cementitious materials, W/C 41%(W/B 35.4%), S/a 50.8% and unit volume of coasre aggregate 0.30 as optimum mix design. Also test result of the fresh and hardened concrete are satisfied with specifications of slurry wall.