• Proceedings of the KSME Conference
• /
• 2000.04b
• /
• pp.574-579
• /
• 2000

In this study. an off-design performance prediction program for centrifugal pumps is developed. To estimate the losses in an impeller flow passage, two-zone model and two-element in series(TEIS) model are used. At impeller exit. the mixing process occurs with an increase in entropy. In two-zone model. there are both primary zone and secondary zone for an isentropic core flow and an average of all non-isentropic streamtubes respectively. The level of the core flow diffusion in an impeller was calculated by using TEIS model. While internal losses in an impeller an automatically estimated by using the above models, some empirical correlations far estimating external losses. far example, disk friction loss, recirculation loss and leakage loss are used. In order to analyze the vaneless diffuser flow. the momentum equations for the radial and tangential directions are used and solved together with continuity and energy equations.

• Proceedings of the KIEE Conference
• /
• 1999.11b
• /
• pp.442-445
• /
• 1999

In this work, to detect of hydrogen in DI water in the generator area of nuclear power plants was fabricated Pd/Pt gate MISFET sensor using Pd membrane. $H_2$ permeation through Pd accounts for external mass transfer, surface adsorption and desorption, transitions to and from the bulk metal, and diffusion within the metal. The identification of pinholes in the generator area of plant is an important safety consideration, as hydrogen build-up gives rise to explosion. For this type of application the sensor needs to be isolated in DI water, accordingly, a Pd membrane was used to separate the DI water. The hydrogen in the DI water was then absorbed on the Pd thin film and diffused into the oil through the thin film. The Pd/Pt gate MISFET sensor, encapsulated by oil, will thereby detect permeated hydrogen.

• The Journal of the Korea Contents Association
• /
• v.2 no.3
• /
• pp.41-58
• /
• 2002

The purpose of this study was to examine the influence Of external environmental context, organizational context, and technical context on adoption and diffusion of B2B EC using innovation framework In this study, factors distinguishing non-adoption companies of B2B EC from adoption companies of B2B EC were customer-supplier power, perceived benefits, top management support, organizational strategy and organizational characteristics. The results of this research weight various B2B EC adoption factors in terms of their strategic importance.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.7 no.1
• /
• pp.127-141
• /
• 2011

This paper provides a method to evaluate the competitiveness based on IT innovativeness considering the adoption phase and shows how to apply the method with a case of foreign market in the early-adoptive phase. The proposed method considers a variety of corporate and market characteristics concerned with the technology adoption, and it consists of several internal and external impacting factors that can influence the level of IT diffusion. Main advantage of this method is the ease of its applicability that allows evaluating the innovativeness, regardless of corporate size, industry type, or level of technology adoption. Therefore, it is possible for this method to evaluate the technology competitiveness easily and repeatedly, in terms of IT innovativeness by inter-organizations and inter-nations. For the case analysis, the Mongolian IT market with several Korean IT joint firms is introduced, and final data resulted from an early-adoptive phase case are analyzed.

• Journal of Korea Society of Industrial Information Systems
• /
• v.3 no.1
• /
• pp.117-139
• /
• 1998

This study is intended to identify the factors affecting the successful information warehouse (IW) implementation through the technology acceptance model. As the IW has played an important role with the organizations, it has become a strategic management tool. However, because the building of an IWS requires a great amound of financing and a multi-period, managers should consider identifying the variables as a predictor of IWS success. The related research areas, such as TAM , TRA, and innovation diffusion theory, and previous research associated with the EWS success factors are reviewed in this paper. Based on the hypotheses presented , the study will empirically test the relationships between six external variable-user involvement, computer self-efficacy, OLAP characteristics, problem difficulty , user training and top management support-and system utilization via user's perceptions of ease of use, unusefulness. This study semmes to be a first attempt in this research area, and its results will provide general guidclines for IWS project managers to enhancement the like hood of system succes.

• Journal of Wetlands Research
• /
• v.5 no.1
• /
• pp.67-78
• /
• 2003

The unsteady 2D convection and diffusion equation is solved numerically for the real-time simulation of suspended load propagation. The streamlined upwind scheme efficiently reduces numerical oscillations due to the high Peclet number in the convection dominant flow. By using the mixed boundary condition to express the external source terms or externally induced suspended load as a function of time in the algorithm, the model is capable of handling not only continuous load cases but also non-continuous suspended load influx. The suspended load transport modelwas verified using a case study for which an analytical exact solution is available and was applied to the real-time simulation of a suspended load influx case on the Mississippi River. The model algorithm can provide a framework upon which water quality as well as contaminant transport models can be built.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1997.04a
• /
• pp.149-154
• /
• 1997

In order to predict the onset of the corrosion of steel bars in the concrete, a mathematical model including the diffusion of chloride ion in aqueous phase of pores, the adsorption and desorption of chloride ions to and from the surface of solid phase of concrete, and the chemical reaction of chloride ions with solid phase was established. Finite element method was employed to carry out numerical analysis. The chlorides penetrating through the wall of concrete structure from the external environment and the chlorides contained in the concrete admixture were confirmed to be two important factors to determine the onset of corrosion of steel bars.

• Journal of Information Technology Applications and Management
• /
• v.12 no.2
• /
• pp.163-184
• /
• 2005

The purpose of this research is to examine the major determinants affecting the usage and performance of information technologies in Daedeok Valley and Zhongguancun venture firms. The development of the research model is based on the theoretical linkages of IDT (Innovation Diffusion Theory) and TAM(Technology Acceptance Model). Seven hypotheses are derived and tested using regression analysis. The results from regression analysis suggest that the usage of Information technologies is affected by innovation characteristics (perceived usefulness) as well as organizational characteristics (top management support, employee capability on information technology acceptance) in Daedeok Valley venture firms. But, The results from regression analysis suggest that the usage of Information technologies is affected by innovation characteristics (perceived usefulness), organizational characteristics (top management support, employee capability on information technology acceptance), and external pressure (environmental uncertainty, intensity of competition) in Zhongguancun venture firms.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.5
• /
• pp.769-774
• /
• 2010

It happened fractures on special bolt which supported main landing gear actuator up-lock rod of aircraft. Cracks were initiated mainly from the center hole and the external thread of the special bolt. To find out failure root causes, metallographic, fractographic analyses as well as test work were carried out. From the fractographic study by SEM work, fracture occurred by a brittle intergranular type failure. The fracture could be occurred primarily by solid-metal-induced embrittlement due to cadmium embrittler penetrated into the flaw existed after machining work for center hole and thread on the bolt during baking treatment processing to eliminate hydrogen. For its successful application, cadmium EP bolts require proper and adequate baking treatment after electroplating, and make no more drilled center hole on the bolt to prevent same failure.

• Proceedings of the KIPE Conference
• /
• 2014.07a
• /
• pp.401-402
• /
• 2014

State of Charge (SOC) and State of Health (SOH) are the key issues for the application of Absorbent Glass Mat (AGM) type battery in Idle Start Stop (ISS) system which is popularly integrated in Electric Vehicles (EVs). However, battery parameters strongly depend on SOC, current rate and temperature and significantly change over the battery life cycles. In this research, a novel method for SOC, SOH estimation which combines the Auto Regressive with external input (ARX) method using for online parameters prediction and Dual Extended Kalman Filter (DEKF) algorithm considering hysteresis is proposed. The validity of the proposed algorithm is verified by the simulation and experiments.