• Journal of Energy Engineering
• /
• v.2 no.1
• /
• pp.45-53
• /
• 1993

This study was directed to an inquiry into a methodology for prioritizing and evaluating R & D alternatives for fuel cell technology, that can provide information for use in future decisions under the current uncertainty. A case study was performed for three cases of fuel cell development under the assumption that basic input data are same. The three cases are the case considering sequential R & D schedule only(Case 1), the case considering equivalent and excluding subprojects(Case 2), and the case allowing parallel efforts for each phase(Case 3). The following results were obtained; the probabilities of success for R & D phases in parallel projects are correlated, the probability of success for each project increases through Case 1, Case 2 and Case 3 successively and the expected dates of commercialization were notably shortened in Case 3.

• Microbiology and Biotechnology Letters
• /
• v.42 no.3
• /
• pp.297-301
• /
• 2014

We examined the effect of ionic liquid on the crystallization efficiency of vancomycin in an increased surface area crystallization with silica gel. The crystallization efficiency was improved by the addition of ionic liquid, [BMIm][$BF_4$]. The addition of ionic liquid (20%, v/v) on the increased surface area crystallization with silica gel dramatically reduced the crystallization time by 6 folds (4 h), compared with the results of the case where the surface area-increasing material and ionic liquid had not been added. In addition, the crystal size of vancomycin was decreased and the crystal quality of vancomycin was improved by increasing the addition of ionic liquid.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.19 no.1
• /
• pp.96-101
• /
• 2009

This paper presents a method for identifying the parameter set of inelastic constitutive equations, which is based on an Evolutionary Algorithm. The advantage of the method is that appropriate parameters can be identified even when the measured data are subject to considerable errors and the model equations are inaccurate. The design of experiments suited for the parameter identification of a material model by Chaboche under the uniaxial loading and stationary temperature conditions was first considered. Then the parameter set of the model was identified by the proposed method from a set of experimental data. In comparison to those by other methods, the resultant stress-strain curves by the proposed method correlated better to the actual material behaviors.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.21 no.2
• /
• pp.112-128
• /
• 1995

This study was undertaken to see the effect of the addition of residential sewage to cosmetic plant wastewater on the aeration time for COD stabilization of the mixture in a bioreactor. Various range of mixing-ratio samples were tested to find the optimal mixing ratio. The combined result of measured COD and the minimum aeration time was desirable when the sewage portion was 80%. It was found that the addition of residential sewage to cosmetic plant wastewater itself reduced the measured COD of the mixture without any further treatment. And during the aeration COD was reduced with increasing the portion of the sewage. These results show that the aeration time for COD stabilization can be reduced by pro-mixing of residential sewage and the cosmetic plant wastewater.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.15 no.7
• /
• pp.553-564
• /
• 1990

The co-efficient matrix of linear second-order partial differential equations in the general form is partitioned with (n-1)x(n-1) submartices and is transformed into the block tridiagonal system. Then the cyclic odd-even reduction technique is applied to this system with the large-grain data granularity and the block cyclic reduction algorithm to solve unknown vectors of this system is created. But this block cyclic reduction technique is not suitable for the parallel processing system because of its parallelism chanigng at every computing stages. So a new algorithm for solving linear second-order partical differential equations is presentes by the block cyclic reduction technique which is modified in order to keep its parallelism constant, and to reduce gteatly its execution time. Both of these algoriths are compared and studied.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.1A
• /
• pp.7-16
• /
• 2003

Handover is very important to support the mobility of user because wireless ATM networks have smaller cell size such as micro/pico cell for broadband mobile multimedia service In this paper, we propose dynamic path reservation handover scheme for fast inter-MSC (Mobile Switching Center) handovers To reduce the handover delay for connection re-routing, the proposed scheme reserves virtual channels from nearest common node to neighbor MSC in advance Especially, our handover scheme predicts the number of inter-MSC handover calls at each period by the prediction algorithm and reserve virtual channels The simulation and analysis results show that our scheme reduce handover complexity and has higher reservation channel utilization, compared with DVCT scheme.

• Journal of Korean Society of Steel Construction
• /
• v.19 no.4
• /
• pp.403-411
• /
• 2007

CFT (Concrete filled steel tube) column has become popular for building construction due to not only its composite effect but also economic effect. However, the conventional CFT column also has its own disadvantages having plastic buckling at the end of column followed by the reduction of strength by yielding of steel tube. An experiment on TR-CFT (Transversely reinforced CFT) column are conducted for making up for conventional CFT column's disadvantages. The experiment parameters are strength of concrete, the layer numbers of carbon fiber sheet. In this study, hysteretic curve, initial stiffness, strength, plastic deformation capacity, and dissipated energy are compared and analyzed between CFT and TR-CFT columns.

• Journal of the Korea Society for Simulation
• /
• v.19 no.3
• /
• pp.17-25
• /
• 2010

It is necessary for the ship dynamic models to realize ship dynamics and to achieve the real-time analysis in the manoeuvring simulation. Generally, simple dynamic models, such as 1st-order differential equation models of turning angle, turning rate, and forward speed, are used in the manoeuvring simulation for multiple ships. Ship dynamic modeling and parameter estimation methods based on its turning test results are proposed in this paper. Parameter estimation methods for the constant speed model and the speed-changing model are mathematically developed and verified by comparing with turning test results of a real ship.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.7 no.4
• /
• pp.159-168
• /
• 2012

The purpose of this study is to analyze the relationship of MOT and NPD performance in medium-sized manufacturing firms. To accomplish the purpose of the study, working hypotheses were established based on the literatures about the impacts of MOT factors on the NPD performance. The sample of this study is as follows : 12 electrical and electronics companies, 18 machine and engineering companies, 16 parts and materials companies. In order to verify hypotheses, the data were collected from team leader and manager of research center, R&D, and production department of these companies and the leader of R&D project team who all had experience in project or were participating in it in latest 3 years. The results of study were summarized as follows : First, in analysis on the reality of MOT factors in sample firms, will of top management level on the MOT was comparatively high but relatedness of business strategy and technology strategy, open R&D system, systematic time scheduling, management of R&D manpower, and developing and adapting PLM system were common level. Second, to improve NPD performance in medium-sized manufacturing firms, will of top management level on the MOT, relatedness of business strategy and technology strategy, open R&D system, systematic time scheduling, management of R&D manpower, and developing and adapting PLM system were intensively required.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.11 s.353
• /
• pp.149-158
• /
• 2006

We proposed a method for improving a performance of TCP downstream between a desktop PC as a fixed host and a PDA as a mobile host in a wired and wireless network based on IEEE 802.11x wireless LAN. With data transmission between these heterogeneous terminals a receiving time during downstream is slower than that during upstream by 20% at maximum. The reason is that their congestion window size will be oscillated due to a significantly lower packet processing rate at receiver compared to a packet sending rate at sender. Thus it will cause to increase the number of control packets to negotiate their window size. To mitigate these allergies, we proposed two distinct methods. First, by increasing a buffer size of a PDA at application layer an internal processing speed of a socket receive buffer of TCP becomes faster and then the window size is more stable. However, a file access time in a PDA is kept nearly constant as the buffer size increases. With the buffer size of 32,768bytes the receiving time is faster by 32% than with that of 512bytes. Second, a delay between packets to be transmitted at sender should be given. With an inter-packet delay of 5ms at sender a resulting receiving time is faster by 7% than without such a delay.