• Structural Engineering and Mechanics
• /
• v.68 no.3
• /
• pp.377-384
• /
• 2018

Bi-stable structure can be stable in both its extended and coiled forms. For the un-stressed thin cylindrical shell, the strain energy expressions are deduced by using a theoretical model in terms of only two parameters. Based on the principle of minimum potential energy, the bi-stable behaviors of the cylindrical shells are investigated. The results indicate that the isotropic cylindrical shell does not have the second stable configuration and laminated cylindrical shells with symmetric or antisymmetric layup of fibers have the second stable state under some confined conditions. In the case of antisymmetric laminated cylindrical shell, the analytical expressions of the stability are derived based on the extremal principle, and the shell can achieve a compact coiled configuration without twist deformation in its second stable state. In the case of symmetric laminated cylindrical shell, the explicit solutions for the stability conditions cannot be deduced. Numerical results show that stable configuration of symmetric shell is difficult to achieve and symmetric shell has twist deformation in its second stable form. In addition, the roll-up radii of the antisymmetric laminated cylindrical shells are calculated using the finite element package ABAQUS. The results show that the value of the roll-up radii is larger from FE simulation than from theoretical analysis. By and large, the predicted roll-up radii of the cylindrical shells using ABAQUS agree well with the theoretical results.

• Journal of Korean Society of Water and Wastewater
• /
• v.33 no.2
• /
• pp.103-110
• /
• 2019

Management of stormwater runoff is considered a nationwide challenge. To deal with this challenge, many researches have been conducted to study initial stage of stormwater fee imposition. The objective of this study was to recommend a framework for stormwater fee imposition not only for funding the stormwater management programs but also for encouraging people to decrease impervious area. This study focused on, regulations, financial resources and international cases related to stormwater runoff management. Polluter pays principle, which is generally recognized environmental policy principle is regarded the basis of stormwater fee imposition. Three components suggested for the stormwater rate structure are 1) stormwater utility revenue requirement, 2) billable equivalent stormwater unit, 3) system unit cost. The key point of stormwater rate structure is the "Equivalent Residential Unit(ERU)". The concept of an ERU is one residential area with a runoff coefficient. The runoff coefficient is that portion of rainfall that becomes runoff rather than infiltrating into the ground. In addition to this, this study took into account the observed data simulation for the separation of stormwater treatment expenditure from the comprehensive wastewater treatment cost.

• Journal of Sasang Constitutional Medicine
• /
• v.23 no.2
• /
• pp.139-152
• /
• 2011

1. Objectives: This research was proposed to find out the selection and form of addition and subtraction of the Sasang prescription. 2.Methods: The related contents of the pathology and the medical action of a Sasang disease were selected in "Donguisusebowon- Sasangchobongyun, -Gabobon, -Shinchukbon(東醫壽世保元-四象草本卷, -甲午本, -辛丑本)", "Donguisasangsinfyun(東醫四象新編)". 3.Results and Conclusions: 1) The change and development of the Sasang prescription. 2) The selection of drugs are caused by immunity of the ordinary times and a class of present disease. 3) Addition and subtraction of the Sasang prescription can divide 4-type.

• Structural Engineering and Mechanics
• /
• v.7 no.2
• /
• pp.159-180
• /
• 1999

The present paper shows a new non-tensorial approach to derive basic equations for various structural analyses. It can be used directly in numerical computation procedures. The aim of the paper is, however, to show that the approach serves as an excellent tool for analytical purposes also, working as a link between analytical and numerical techniques. The paper gives a method to derive, at first, expressions for strains in general beam and shell analyses, and secondly, the governing equilibrium equations. The approach is based on the utilization of local fixed Cartesian coordinate systems. Applying these, all the definitions required are the simple basic ones, well-known from the analyses in common global coordinates. In addition, the familiar principle of virtual work has been adopted. The method will be, apparently, most powerful in teaching the theories of curved beam and shell structures for students not familiar with tensor analysis. The final results obtained have no novelty value in themselves, but the procedure developed opens through its systematic and graphic progress a new standpoint to theoretical considerations.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10a
• /
• pp.393-396
• /
• 1996

This paper studies electrostatically suspended induction motors (ESIM). The ESIM possesses the rotating ability of an ordinary electrostatic induction motor, in addition to providing contactless support by electrostatic suspension. To accomplish these two functions, a feedback control strategy and the operating principle of an ordinary electrostatic induction motor are used. The stator possesses electrodes which exert the electrostatic forces to the rotor and are divided into a part responsible for suspension and one for rotation. Two rotor types are utilized: a polished glass disk without any surface treatment, and a polished glass disk covered with a thin layer of conductive material (ITO layer) on only one side. In this paper, the principle of the ESIM is described, followed by stator electrode design, experimental apparatus, control strategy for stable suspension. Experimental results show that the glass disk has been rotated with a speed of approximately 70 rpm while being suspended stably at a gap length of 0.3 mm.

• Proceedings of the KIPE Conference
• /
• 1997.07a
• /
• pp.116-123
• /
• 1997

This paper was described about principle and form of proposed circuit made use of soft switching technology ZVS(Zero Voltages Switching) and ZCS(Zero Current Switching) to reduce turn on and off loss at switching. Also, the analysis of the proposed circuit is described generally by using normalized parameter and basic operating principle and driving characteristics have been evaluated as to switching frequency and load p arameter. Based on the characteristics value, a method of circuit design is proposed. In addition, Pspice's simulation and experimental waveforms are compared with theoretical ones. The experimental results shows that the proposed Inverter can be used practically such as power source system for induction cooker etc.

• Journal of Information Technology Applications and Management
• /
• v.11 no.4
• /
• pp.147-167
• /
• 2004

This study was empirically performed to demonstrate the development propensity and quality of the public software projects in Korea. Tile sample employed in this study contains 168 auditing reports on 107 public software projects which were carried out in the period of 1998 to 2003. The important findings of this study can be summarized as follows. The quality issue in the development process is getting more important with the lapse of time. In addition, the importance of end users' conveniency increases from year to year. Although the Pareto Principle(20 : 80 principle) is not applied strictly, most problems are caused by a few items. Finally, we find evidence that the overall Quality of public softwares is positively influenced by the information system auditing.

• Proceedings of the KIEE Conference
• /
• 1991.07a
• /
• pp.411-416
• /
• 1991

Operation simulation is a key factor to evaluate investment and operation in a power utility. Probabilistic production simulation is of major concern. With pumped-storage plant, production simulation is not an easy task, because its economy should fully be exploited. In addition, usual operation interval is a week rather than a day. Most existing models are based on approximate production simulation such as adopting simple priority orders of generations. This study is based on the more elaborate model developed by authors. Further, a policy of weekly coordination is established based on the Maximum Principle. Chronological load curve instead of usual load duration curve is used and the accuracy in simulation is enhahced. Resulting economics are compared. Deviation between these two toad curve is shown.

• Journal of the Korean Society of Food Culture
• /
• v.17 no.4
• /
• pp.496-529
• /
• 2002

The theory-the doctrine of Confucius and Mencius was an objective existance in Chinese dietary culture history, but it was ignored in the last two thousand years. In addition, some people misunderstood Confucius' and Mencius' thoughts and statements. This paper believes that the doctrine of Confucius and Mencius is Confucius' and Mencius' diet opinions, thoughts, theories and basic style in their diet experiences. Confucius' diet experience and Mencius' diet experience were alike, and Mencius' experience carried on Confuius' and theirs were the same in some sections. They all stay their diet standard to their stomach and don't persue good meal. They all thought resolving people's diet was important for a country and for the politic problems. Mencius succeeded Confucius' diet thoughts and put them to the theories-diet principle, diet standard, and diet morality. This paper deeply discusses theory, developing history condition and the affection and position in Chinese diet history of the doctrine of Confucius and Mencius.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.54 no.6
• /
• pp.287-293
• /
• 2005

Equations have been derived for computing electromagnetic forces by using the Continuum Design Sensitivity Analysis based on the Continuum Mechanics and the Virtual Work Principle. The resultant expressions have similar terms relating to the Korteweg-Holmholz force density, Maxwell Stress Tensor and Magnetic Charge Method but numerical implementation of the proposed scheme leads to efficient calculation and improved accuracy. In addition, the method can be easily applied to computing the magnetic force distribution as well as the global force. Results show the aforementioned advantages in comparison with the conventional methods.