• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.7
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• pp.1001-1012
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• 1998

This paper reports the analysis of dynamic characteristics of air-cooled condenser. At first, there is an assumption that the superheated vapor flows into the condenser inlet. And in order to consider the effect of pressure change in the dynamic characteristics of the condenser the combined system of condenser and compressor was used. By using the equation of energy balance and the equation of mass balance, the basic equation for describing the dynamic characteristics of condenser can be derived. The transfer function for describing dynamic response of the condenser to flow rate change outlet can be obtained from using linearizations and Laplace transformations of the equation. From this transfer function, analytical investigation which affects the frequency responses of condenser has been made. Through this study, it became possible that the information about the dynamic characteristics of air-cooled condenser is offered. While the average heat transfer coefficient of the refrigerant side necessary for the theoretical calculation of the dynamic characteristics is given by calculation method for the tube length and pressure drop of air-cooled condenser.

• Knowledge Management Research
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• v.4 no.2
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• pp.19-34
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• 2003

This paper analyzes 96 Korean companies to illustrate the relationship between the knowledge management strategies and task characteristics. Knowledge management strategies can be categorized as being codification- and personalization-oriented. Task characteristics are analyzed from the perspective of content-oriented, process-oriented, number of exceptions, and analyzability. These results illustrate how companies should align the knowledge management strategies with task characteristics. It is found that codification strategy is more likely to be associated with high content-oriented and high analyzability task, and personalization strategy is with high process-oriented task. The survey result confirms that managers should adjust knowledge management strategies in view of the characteristics of the task.

• International Commerce and Information Review
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• v.10 no.3
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• pp.369-389
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• 2008

The purpose of this paper is to study on relations between alliance types and firm's characteristics in Korean semiconductor industry to prevent trade disputes. The recognition of firms' business strategies tend to be subjective and there is a limitation to use the guiding principles due to subjectivity. If there are additional guiding principles which view strategic alliances in relation to more objective characteristics associated with firms, such as their size, function, scope, and location, they will be useful tools for executives and managers in their business practices. We analyze strategic alliances how firms; external characteristics become decision factors for selecting appropriate forms of strategic alliances. Previous research works with focus on alliance forms are reviewed, then an analytical framework is described with certain categorization of firms' characteristics and alliance forms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.204-207
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• 2007

Film bulk acoustic wave resonator (FBAR) technology has attracted a great attention as a promising technology to fabricate the next-generation RF filters mainly because the FBAR technology can be integrated with current Si processing. The RF filters are basically composed of several FBAR devices connected in parallel and in series, and their characteristics depend highly on the FBAR device characteristics. Thus, it is important to design high quality FBAR devices by device or process optimization. This kind of effort may enhance the FBAR device characteristics, eventually leading to FBAR filters of high performance. In this paper, we describe the methods to more effectively improve the resonance characteristics of the FBAR devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.130-132
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• 2001

We have investigated current-voltage (I-V) characteristics of organic light-emitting diodes based on $TPD/Alq_3$ organics depending on the application of forward-reverse bias voltage. Luminance-voltage characteristics and luminous efficiency were measured at the same time when the I-V characteristics were measured. We have observed that the I-V characteristics shows a current mxima at low voltage, which is possibly not related to the emission from $Alq_3$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.201-204
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• 2001

In this paper, for modeling of electrical characteristics in Poly Silicon Thin Film Transistors with process parameters set up optimum values, So, the I-V characteristics of poly silicon TFT parameters are examined and simulated in terms of the variations in process parameter. And these results compared and analyzed simulation values with examination value. The simulation program for characteristic analysis used SUPREM IV for processing, Matlab for modeling by mathematics, and SPICE for electric characteristic of devices. Input parameter for simulation characteristics is like condition of device process sequence, these electric characteristic of $I_D-V_D$ $I_D-V_G$, variations of grain size. The Gate oxide thickness of poly silicon are showed similar results between real device characteristics and simulation characteristics.

• MALSORI
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• no.47
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• pp.97-107
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• 2003

Speaker change detection is to detect automatically a point of time at which speaker was replaced. Since feature parameters used for speaker change detection depend not only on speaker characteristics but also on phonetic characteristics, spoken contents included in the feature parameters inevitably causes performance degradation of speaker change detection. In this paper, to alleviate this problem, a method to normalize phonetic variations in speech feature parameters is proposed for emphasizing changes due to speaker characteristics. Experimental results show that the proposed method improves the performance of speaker change detection.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.225-232
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• 1999

The effect of manufacturing parameters such as molding and curing conditions on friction characteristics of friction materials was studied using a pad-on-disk type friction tester. Friction materials containing 15 ingredients were investigated for an optimal manufacturing condition for the best friction characteristics employing Taguchi robust experimental design. The main effects were different for mechanical properties and friction characteristics and were strongly influenced by manufacturing conditions. An optimum manufacturing condition was obtained to achieve the best friction characteristics concerning mechanical properties(hardness, porosity, wear resistance), friction stability, and change of rotor temperature.

• Journal of Preventive Medicine and Public Health
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• v.42 no.4
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• pp.215-222
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• 2009

Objectives : Vigorous physical activity is a well-known method to promote people s health. This research aims to investigate whether perceived neighborhood characteristics affect vigorous physical activity among adult Seoul residents (aged 19 to 64). Methods : Utilizing the 2005 Seoul Citizens Health Indicators Survey data, this study estimates the probability of vigorous physical activity. Particular attention is given to the effects of three perceived neighborhood characteristics satisfaction with relationship to the neighborhood, satisfaction with park and recreational facilities, and satisfaction with public security). Logistic regression models are analyzed separately by gender for the parameter estimation. Results : Vigorous physical activity is positively associated with three perceived neighborhood characteristics for women, while neither significant nor substantive association is found for men. Conclusions : As vigorous physical activity among Seoul citizens is differentially affected by perceived neighborhood characteristics and by gender, a different approach will be needed to increase vigorous physical activity of men and women in Seoul.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.986-990
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• 2002

Dual Mass Flywheel(DMF) is used in order to improve the vibration characteristics of drivetrain of manual transmission vehicles. Regardless of its complexity and high cost, application of DMF is keep increasing due to a trend of using Diesel engines in passenger cars and light weight design of drivetrains. Modeling and analysis of DMF is rather simple, but finding out optimum parameters of damper may not be easy. Furthermore, its realization in DMF has some limitations due to DMF's structure and its structure dependent damping characteristics. Requirements on spring-damper characteristics of DMF has been reviewed and investigations on structures and damping characteristics of currently Produced DMFs have been made in this paper. Also, ideal spring and damper characteristics has been proposed based on such investigations.