• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.159-163
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• 2005

A dynamic vibration absorber using the Zener's model has been taken into account with respect to frequency response characteristics. The concept of the tuned mass damper with a single degree of freedom has been well applied for many industrial fields, because many researchers have extensively studied various basic characteristics, performance and optimization methods for long time. The Zener's model has an additional spring, which is connected between a damper and a mass, while the tuned mass damper with a single degree of freedom consists of a mass, a spring and a damper connected in parallel. In previous works, the basic performance and characteristics of the Zoner's model as a dynamic vibration absorber have not been investigated. In this study, the frequency response characteristics according to the parameter change of the Zener's model have been described. In order to find the optimum value of several parameters, we use iterative scheme with three dimensional frequency response diagram by MATLAB programming. Present results shows the Zener's model can give more good damping performance than the simple tuned mass damper, and the numerical of optimization method should be developed for the efficient vibration absorbtion.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.6 s.123
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• pp.515-523
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• 2007

As environmental vibration requirements on precision equipments get more stringent, use of pneumatic vibration isolators becomes more crucial and, hence, their dynamic performance needs to be further improved. Dynamic behavior of those pneumatic vibration Isolation tables is very important to both manufacturer and customer as performance specifications. Together with conventional transmissibility, transient response characteristics are another critical performance index especially when movements of components, e.g., x-y tables, of the precision equipments are very dynamic. In this paper, analysis on transient response of a pneumatic vibration isolation table loaded by a mass moving on it is presented. This is a conventional dynamics problem on a rigid body with 6 degree of freedom and a mass with another degree of freedom. How to obtain transient responses of the isolation table is described when the movements of the mass are prescribed relative to the table.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.495-500
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• 2006

Nowadays HCFCs refrigerant are restricted because it cause depletion of ozone layer. However, natural gases such as ammonia as an organic compound, propane and propylene as hydrocarbon are easy and cheap to obtain as well as environmental. Accordingly, this experiment apply the $NH_3$ and R22 to study the performance characteristic from the superheat control and compare the energy efficiency of two refrigerants from the high performance. The condensing pressure of refrigeration system is increased from 15bar to 16bar and degree of superheat is increased from 0 to $10^{\circ}C$ at each condensing pressure. As the result of experiment, when comparing the each COP, we knew the $NH_3$ is suitable as the alternative refrigerant of the R22.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.1
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• pp.149-157
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• 2008

This study examined the cost consciousness, food materials satisfaction, job satisfaction, and degree of food materials management of chefs, as a means to increase food materials management efficiency in hotel restaurants and to make suggestions, for efficiently reducing food material costs, Chefs from eleven 5-star hotels and one exceptional-grade restaurant in Seoul were asked to fill out a questionnaire for sampling. A total of 350 questionnaires were distributed and 334 were returned (95.4% return rate). The characteristics of the respondents were examined by population statistics analysis, and the chefs' cost consciousness, food materials satisfaction, and job satisfaction were examined by descriptive statistics after reliability and propriety analyses. The degree of cost consciousness in the respondents was very high and this degree of consciousness proved to have a partially significant impact on the degree of food materials management. That is when the chefs were more conscious about cost, the degree of food materials management was high. This implies that food materials satisfaction can be enhanced by enhancing the degree of food materials management. Job satisfaction also had a partially significant, influence on the degree of food materials management. Therefore, it is necessary to maintain consistency in the quality and inspection of food materials, provide related information, enhance the satisfaction level for standards of food materials and improve policies for welfare and career after retirement in order to enhance the job satisfaction of chefs and subsequently reduce costs in relation to the level of food materials management.

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.91-100
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• 2007

The most important thing for driver's safety on the road is equipment of crash cushion as a vehicle protection safety facility. But development of crash cushion is defective because there's no rational and reality way of design. And also without an alternative plan, it rely on crash test hereby it suffers a great economic loss and wastes time. This study that uses data of cash test proves the suitability of single degree of freedom which considers the safety of passengers about three-dimensional complicated Crash Analysis. As the study analyzes the conduct of crash cushion, it want to develop the effective method of design on Single Degree of Freedom Crash Cushion. And it presents the way of crash cushion design through making a crash analysis model with single degree of freedom. To verify the validness of the crash cushion plan, with single degree of freedom plan, we make the level CC2 crash cushion and execute the crash test. A performance test brings satisfied result and a plan of single degree of freedom crash cushion is proven as an one of the way to be a good system which can design crash cushion.

• Korean Management Science Review
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• v.18 no.1
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• pp.89-105
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• 2001

The performance of Cellular Manufacturing (CM) systems has been rigorously investigated during the last two decades, but the extent of empirical research on CM is limited. A major objective of this study is to examine the relationship between critical success factors, employees' implementation attitudes and performance of CM systems. Two hypothesis were formulated &d Tested: (1) The impact of critical success factors on performance and to what extent does certain critical success factors correlate with performance\ulcorner (2) How does the relationship between critical success factors and performance differ by employees' implementation attitudes\ulcorner Results from the study provide partial support for relationship between critical success factors (infrastructure, organizational immersion, autonomous management) and performance. The results also show that differences in performance of organizations grouped by degree of employees' attitudes could be found.

• The Korean Journal of Health Service Management
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• v.8 no.3
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• pp.113-124
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• 2014

This study was the development of job-based curriculum present the basic data for the 207 people surveyed dental hygienists in clinical analysis. The data was analysed with frequency, t-test and one-way anova using the spss 20.0 windows. Person of preventive dental treatment in main duty was significantly highest than among others. In conclusion, the dental hygienist will perform the most medical support services, However the main duties of dental hygienists to perform preventive dental treatment for major help when the highest degree. Among oral hygiene management duty-related subjects showed the most helpful. Therefore dental hygiene curriculum to train dental hygienist should be organized to help with job performance in the field of clinical activities.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.596-608
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• 2003

Weaning is a complex phase when the mammal suffers the action of different stressors that contribute to negatively affect the efficiency of the intestinal mucosa and of the whole local integrated system, that acts as barrier against any nocuous agent. The components of this barrier are mechanical, chemical, and bacteriological; immunological and not. The development of contact with a saprophyte microflora and the maintenance of feed intake after the interruption of motherly nutrition are essential for the maturation of an equilibrated local immune function and for a functional integrity of villi. Opportunities and limits of some dietary strategies that can contribute to reduce negative effects of weaning on health and performance are discussed. Knowledges on the possible mechanism of action of probiotics are upgraded, particularly for their supposed role in the balance between different immune functions (effectory/regulatory). Some tools to control pathogen microflora are reviewed (acids, herbs, immunoglobulin sources) and practical feeding systems are proposed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.257-260
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• 2001

The primary objective of Supply Chain Management (SCM) is to optimize the cash, material and information flow considering all components of Supply Chain (SC) . The plan, established for achieving such objective, is called Supply Chain Planning (SCP) . This SCP gives each SC component specific volume or operation task, should be done in specific due date, for optimizing SC. In detail, the degree of accomplishment for SCP, depends on the SCP achievement of each SC components, is very close to successful SCM. However, this achievement is affected by uncertainties about time and volume. In general, reliability concepts means the probability that a product or system will perform its specified function under prescribed conditions without failure for a specified period of time. Therefore, the concept of Supply Chain Reliability (SCR) and an analytic methodology to calculate the degree of achievement SCP using reliability concept are proposed in this paper. SCR means that the degree of achievement for SCP considering all SC components in due date. SCR can be used to measure the performance of whole supply chain and indicate the direction of SCP.

• Journal of Powder Materials
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• v.16 no.1
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• pp.56-62
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• 2009

The degree of WC decomposition and hardness of thermally sprayed WC-Co coatings are important factors determining the wear resistance of the coatings. In order to minimize the degree of decomposition and to increase hardness, the effects of processing parameters of high velocity oxyfuel(HVOF) spraying on various characteristics of nanostructured WC-12Co coating have been evaluated by an experimental design method. The HVOF sprayed WC-12Co coatings consisted of various carbide phases including WC, $W_2C$ and $W_3Co_3C$, with a much reduced carbon content. The degree of WC decomposition and decarburization was affected by changing barrel length and spray distance. The hardness of WC-Co coatings was strongly related to droplet temperature at substrate, and increased with increasing fuel addition and/or decreasing spray distance. The effective control of processing parameters was discussed in detail for manufacturing a high performance WC-Co coating.