• 한국생산제조학회지
• /
• 제22권4호
• /
• pp.740-746
• /
• 2013

Angular contact ball bearings are often adopted for a high-speed spindle owing to their durability against axial and radial loads. The dynamic characteristics of an angular contact ball bearing, however, are very complicated because they are dependent on the applied loads as well as on the system configuration. This study systematically analyzes the radial-load-dependent characteristics of spindles as well as angular contact ball bearings. Toward this end, a spindle dynamic model along with the bearing dynamics model is established. An iterative solution algorithm is implemented to resolve the statically indeterminate problem associated with spindle-bearing systems subjected to radial load. Two numerical examples are provided to investigate the spindle and bearing characteristics as a function of radial load with regard to the system configuration.

• 한국식품조리과학회지
• /
• 제13권4호
• /
• pp.410-416
• /
• 1997

Changes in sensory and physical characteristics of Wanjajeon (Korean pan fried meat balls) were investigated during chill storage for a hospital cook/chill foodservice system. Wanjajeon was cooked, stored at 2$^{\circ}C$ or 7$^{\circ}C$ for 4 weeks, and reheated by using a microwave oven. The physical characteristics such as texture, color and organoleptic properties were measured. The chewiness of Wanjajeon increased during 4 weeks of storage at both temperatures. Reheating of stored Wanjajeon resulted in a significant increase in the hardness and chewiness. The redness (a value) was significantly increased, while the lightness and yellowness (L and b values) were changed slightly. Sensory evaluation showed that Wanjajeon was acceptable for up to 3 weeks of storage at 2$^{\circ}C$ and to 2 weeks at 7$^{\circ}C$. The sample stored at 2$^{\circ}C$ was more acceptable than that of 7$^{\circ}C$ storage through the whole period.

• 한국가시화정보학회지
• /
• 제8권2호
• /
• pp.51-55
• /
• 2010

Flow characteristics of a free-horizontal-axis-turbine (FHAT) current power generation system have been investigated by the use of a volumetric PTV. Three types of FHAT system (S50, SE50, S65) have been tested under the current speed 1.35 knot, 1.5 knot and 2 knot. The width of the blade installed around the body is 50 mm. Based upon the power generation characteristics of the FHAT, the flow features of the blade have been investigated. Among the three models it has been verified that the S65 is the most appropriate for power generations.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
• /
• pp.29-32
• /
• 2008

Testing was conducted to determine the performance of a residential fuel cell system when subjected to DSS and WSS operation, especially for start-up and shut-down characteristics. In terms of start-up time, it took about 70min to start output power generation and stably to reach 1kW at cold start. Measurement of the characteristics of heat and power generation were carried out at start-up and shut-down time. Fuel gas is used for heating both reformer and stack from start-up to the beginning of power generation. In terms of start-up and shut-down characteristics, it was important to control the reformer temperature precisely. The average output water temperature during the rated output operation(960W) was $63.2^{\circ}C$ constantly. The results of the investigation are being used to develop a new test protocols for residential fuel cell system.

• 한국전기전자재료학회논문지
• /
• 제25권5호
• /
• pp.403-408
• /
• 2012

In this paper, we propose useful load flow algorithms called FEDL (fast enhanced decoupled load flow). The proposed load flow method can improve the convergence characteristics particularly when the P-Q coupling becomes significant and the power system operating states deviate from the conditions required for stable convergence of the FDL by reflecting in part the effects of the off-diagonal terms in the Jacobian. In our test with IEEE AEP-30 bus system and RTS-96 73-bus system, it converge even when the fast decoupled load flow (FDL) and its variations keeping load flow matrices constant experience convergence problems. Test results show promising performances of the proposed algorithms in their convergence characteristics both in number of iterations and overall convergence speeds.

• 지식경영연구
• /
• 제9권2호
• /
• pp.63-86
• /
• 2008

Knowledge management system(KMS) was introduced into the company in order to apply knowledge management. But according to KMS is changed into information management system, the company is considered Community in Practice(CoP) instead of KMS. Because within CoP, individuals can interact with one another to solve problems, test new ideas, learn about new developments in their field and build a sense of affiliation with others in similar circumstances. In spite of it's importance there is few empirical study about CoP. So the purpose of this study is to examine which personal characteristics influence knowledge sharing and which context factors(including structural and relational characteristics) moderate relationship between individual characteristics and knowledge sharing within CoP through empirical study.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 A
• /
• pp.115-117
• /
• 2002

In general, it is supposed that load characteristics of high and low voltage distribution line are always coincidence. But in practical distribution system, voltage variation characteristics of high and low voltage distribution line are not same. Then in this paper, we proposes a voltage regulation method considering load variation characteristics of high and low voltage distribution line in distribution system.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.519-524
• /
• 2003

In this paper we discuss the dynamic characteristics of the in-arm type hydropneumatic suspension unit(ISU). For this, two accurate models are introduced. The first one is the Benedict-Webb-Rubin equation which is adopted for the spring behavior of a real gas. This equation is applicable for the high pressure of the nitrogen gas which acts as a spring in ISU system. The second one describes the behavior of a damper, which is divided into four parts - jounce-loading, jounce-unloading, rebound-loading and rebound-unloading. This approach gives a good approximation of the real damper system. For the comparison purpose, the numerical results of the dynamic behavior of ISU system using a real gas and an ideal gas are given in the paper.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1995년도 추계학술발표회논문집(1)
• /
• pp.117-122
• /
• 1995

An Integrated Test Facility(ITF) is a human factors experimental environment to evaluate an advanced man machine interface(MMI) design. The ITF includes a human machine simulator(HMS) comprised of a nuclear power plant function simulator, man-machine interface, experiment control station for the experiment control and design, human behavioural data measurement system, and data analysis and experiment evaluation supporting system(DAEXESS). The most important features of ITF is to secure the flexibility and expandibility of Man Machine Interlace(MMI) design to change easily the environment of experiments to accomplish the experiment's objects In this paper, we describe a development scope and characteristics of the ITF such as, hardware and software development scope and characteristics, system thermohydraulic modelling characteristics, and experiment station characteristics for the experiment variables design and control, to be used as an experiment environment for the evaluation of VDU-based control room.

• 통상정보연구
• /
• 제10권2호
• /
• pp.63-87
• /
• 2008

This study investigates the relationship between perceived system characteristics of Internet shopping mall and loyalty, and examines how perceived website attractiveness and flow play mediating roles between perceived system characteristics of Internet shopping mall and affective commitment in the context of Internet clothing shopping mall. For these purposes, the author developed a structural model which consists of several variables. In this model, perceived system characteristics of Internet shopping mall that consist of such as familiarity, reputation, uniqueness, positive emotion, self-efficacy, and interactivity were proposed to affect the website attractiveness and flow, and in turn, result in higher affective commitment. Thus, perceived website attractiveness and flow were proposed as core mediating variables between perceived mobile service characteristics and affective commitment. To test unidimensionality and nomological validity of the measures of each construct, the author employed scale refinement procedure. The results of reliability test with Cronbach's, and confirmatory factor analysis warranted unidimensionality of the measures for each construct. In addition, nomological validity of the measures was warranted from the result of correlation analysis.