• Explosives and Blasting
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• v.23 no.1
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• pp.65-77
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• 2005

Reflecting the fact that there are increasing number of old high-story apartment structures in urban area, it is expected that the demand of blasting demolition will increase in the near future. It is of great important to make up for the insufficient empirical knowledge in blasting demolition through priori method such as computer simulation. Computer simulation of the blasting demolition involves complicated process. In the past domestic researches, two-dimensional bonded particle model was used to examine the overall demolition behavior of a five-story simple structure. It was observed that the two-dimensional simulation did not properly simulate the collapsing behavior of a structure mainly due to the reduced degree of freedom. In this study, three-dimensional simulation was tried. It consumed a great amount of calculation time, which limited the extent of the study. A few parameters, such as delay times, amount of charge at each hole, ball properties, were modified in order to check oui; their effect on the collapsing behavior. The differences were observed as expected but the collapsing behavior did not exactly coincide with the test blasting with a scaled model.

• Journal of the Korean Chemical Society
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• v.8 no.2
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• pp.68-74
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• 1964

Water has the melting point, the boiling point, the heat of fusion, and the heat of vaporization all much higher than would be normally expected from the hydrogen compounds of the other members of the oxygen family. Another unique characteristic of ice-Ⅰ is its volume decrease which takes place in its melting. A number of significant efforts have been made in the past to explain these properties quantitatively. The authors, reasoning from the unusually great free surface energy of water and the characteristic volume change on melting, propose the structural model of liquid water as follows. On melting, fluidized vacancies of a molecular size are introduced. Thereupon, for the unusually great surface energy density, molecules surrounding the vacancies become to have close packed arrangement. But molecules not in direct contact with vacancies should still possess the original structure i. e., ice-Ⅰ. When a molecule adjacent to a vacancy jumps into the vacancy, the molecule attains the gaslike degree of freedom. Using the above model, the authors had developed the liquid partition function of water by applying the theory of significant structures in liquids. Molar volume, vapor pressure, entropy of fusion and entropy of vaporization were calculated over a wide temperature range. The results show good agreement with experimental observations.

• Fashion & Textile Research Journal
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• v.16 no.6
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• pp.987-994
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• 2014

The purpose of this research is to propose employee uniforms for tourist hotels on Jeju Island, such uniforms that embrace Jeju's unique culture and promote the tourism of Jeju Island. It has been suggested that there exists a need for hotel employee uniforms to attract more tourist attention and boost Jeju's tourism industry. We designed the uniform after analyzing the empirical data collected from academia thesis, periodicals, papers and pictures from internet search, and fashion industry magazines. The uniform analysis and production procedures are as follows: (1) precedent research case review (2) current (existing) uniform status survey (3) latest fashion trend analysis (2010 - 2014) (4) creating the uniform implementing the trend-based design with Gal Cheon, Jeju's cultural product material. We found tipping points of the design through literature and trend analysis; we developed appropriate uniforms accordingly that are harmonious with Jeju's unique identity. We received great evaluations on the appearance and comfort as well. A new concept of uniform featuring Gal Cheon has been proposed. It is expected that the uniforms will promote the brand image of Jeju as an international freedom city and its culture.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.1 s.244
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• pp.18-25
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• 2006

The purpose of this research work is to demonstrate a successful application of hybrid-mixed formulation and nodeless degrees of freedom in developing a very accurate in-plane curved beam element for free vibration analysis. To resolve the numerical difficulties due to the spurious constraints, the present element, based on the Hellinger-Reissner variational principle and considering the effect of shear deformation, employed consistent stress parameters corresponding to cubic displacement polynomials with additional nodeless degrees. The stress parameters were eliminated by the stationary condition, and the nodeless degrees were condensed by Guyan Reduction. Several numerical examples indicated that the property of the mass matrix as well as that of the stiffness matrix have a great effect on the numerical performance. The element with consistent mass matrix produced best results on convergence and accuracy in the numerical analysis of Eigenvalue problems. Also, the higher-order mixed curved beam element showed a superior numerical behavior for the free vibration analyses.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.4
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• pp.19-29
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• 1995

This paper discusses the stick-slip phenomenon of the driveline system of a vehicle in consideration of friction. Friction is operated on the between of flywheel and clutch disk. The expressions for obtaining the results have been derived from the equation of motion of a three degree of freedom frictional torsion vibration system which is made up driving part(engine, flywheel), driven part(clutch, transmission) and dynamic load part(vehicle body) by applying forth-order Rungekutta method. It was found that the great affect parameters of the stick-slip or stick motion were surface pressure force between flywheel and clutch disk, time decay parameter of surface pressure force and 1st torsional spring constant of clutch disk when driveline system had been affected by friction force. The results of this study can be used as basic design data of the clutch system for the ride quality improvement of a car.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.9
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• pp.905-912
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• 2008

Notion sickness is well known to be caused by long time exposure to the very low frequency motion in the multiple axes of human body Since the vestibular system for the perception of low frequency motion is located in the head, accurate measurement of 6 degree of freedom head motion is of great importance. In this study, the measurement system consisting of a safety helmet and 9 translational accelerometers was constructed for the estimation of 3 translational and 3 rotational motions of human head. Since estimation errors of 3 rotational components can be significantly magnified even by small offset of the sensitivity axis from the geometric center of an accelerometer, accurate measurement of sensitivity axis must be preceded. The method for accurate estimation of the offset was proposed, and the effect of offset on the estimation of angular acceleration was investigated.

• Journal of Powder Materials
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• v.26 no.6
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• pp.528-538
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• 2019

The transition from "More-of-Less" markets (economies of scale) to "Less-of-More" markets (economies of scope) is supported by advances of disruptive manufacturing and reconfigurable-supply-chain management technologies. With the prevalence of cyber-physical manufacturing systems, additive manufacturing technology is of great impact on industry, the economy, and society. Traditionally, backbone structures are built via bottom-up manufacturing with either pre-fabricated building blocks such as bricks or with layer-by-layer concrete casting such as climbing form-work casting. In both cases, the design selection is limited by form-work design and cost. Accordingly, the tool-less building of architecture with high design freedom is attractive. In the present study, we review the technological trends of additive manufacturing for construction-scale additive manufacturing in particular. The rapid tooling of patterns or molds and rapid manufacturing of construction parts or whole structures is extensively explored through uncertainties from technology. The future regulation still has drawbacks in the adoption of additive manufacturing in construction industries.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.8
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• pp.835-841
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• 2014

In this paper we propose a swing-up strategy for a single inverted pendulum. The proposed method has a feature whereby can handle the input and output constraint of a pendulum in a systematic way. For the swing-up of a pendulum, we adopt a 2-DOF control structure that combines the feedforward and feedback control. In order to generate the swing-up feedforward trajectories that satisfy the input and output constraint, we formulate the problem of generating feedforward trajectories as a nonlinear optimal control problem subject to constraints. We illustrate that the proposed method is more flexible than the existing method and provides great freedom in choosing the actuator of the inverted pendulum. Through an experiment, we show that the proposed method can swing a pendulum upward effectively while satisfying all the imposed constraints.

• Korea Journal of Hospital Management
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• v.17 no.4
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• pp.71-86
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• 2012

The study was a descriptive research to investigate the effect of job satisfaction and self-leadership of members of small and middle-sized hospital on organizational commitment. Collection of data was conducted throughout members of small and middle-sized hospitals with explanation of purpose from 2011, Oct, 1st to 10th. Collected data was analyzed by T-test, ANOVA, Scheffe test and hierarchical regression analysis with utilizing SPSS Win 16.0. As a result of the expected effect, a degree of effect on organizational commitment has explanation 65.1%(F=183.804) on job satisfaction and self leadership. Also, it was job satisfaction that was found to be more effective, where explanation for it was ${\beta}$=.755 and self-leadership ${\beta}$=.264. With considering these facts, both factors are effective for organizational commitment. Therefore, to improve organizational commitment, it pays systemized strategies and ever more proactive efforts. To strengthen the self leadership, it needs changes in cultural aspects of hospitals to enlarge accessibility to information and opportunities for education and to expand freedom in their responsibility. Great effort on changing in cultural aspects of hospital would, based on effective interrelationship with members, improve efficacies of organization and efficiency of management.

• International Journal of Human Ecology
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• v.9 no.1
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• pp.5-16
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• 2008

Development of technology in the $20^{th}$ century has made great contributions to women's lives. With the development of digital convergence, home network, and DMBs (Distance Method Bracings), the ubiquitous technology information era is expected to create a new progressive era for women. The purpose of this study is to investigate the lifestyle that Korean women would like to pursue, especially in regards to the sense of value within the personal and social life of each individual. As a method to suggest how the socio-cultural trends of women's lifestyle will change in the ubiquitous era, qualitative interviews have been conducted over 6 groups with 77 persons between the digital ages of 20s and 30s, living in Seoul. The majority had positive opinions regarding the economic, cultural, emotional, and physical prospects of the ubiquitous information environment. Results show high expectations evolved around freedom from household chores, the equality between the sexes (at home and in society), enhancing the working environment at home, an expansion of human relationships leading to creative knowledge, being able to maintain a single life without economic constraints, and the enjoyment that the internet provides. for suggestions to improve the quality of women's lifestyle through ubiquitous technology, issues such as individual based customization, time management, creating emotional hyperspaces, multi-media communication systems, and women as leaders were studied.