• 한국기계연구소 소보
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• s.16
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• pp.83-94
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• 1986

Grinding machine, one of the precision machine tool, requires high accuracy in spindle system. But, recent Inspection and Test reports by KIMM shows high inferio¬rity ratio in home-made grinding machines and points out that this is mainly due to the lack of design ability and assembling technique of spindle system. In this paper, therefore, static stiffness, dynamic characteristics, thermal defor¬mation and error motion of spindle system were studied. With these results, we presented the general data to design and assemble the spindle system. Test of spindle system modified by this study showed that several factors affecting machining accuracy were improved largely.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1169-1181
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• 1994

Vibration isolation of mechanical systems, in general, is achieved through passive or active vibration isolators. Passive vibration isolator has an inherenrt performance limitation. Whereas, active vibration isolator provides significantly superior vibration-isolation performance at the cost of energy sources and sensors. Recently, in many cases, such as suspension system, precision machinery ... etc, active isolation system outweighs its limitation. Therefore, many studies, researches, and applications are carried out in this field. In this study, vibration-isolation characteristics of an active vibration control system using electromagnetic force actuator are investigated. Several control algorithms including optimal, feedforward are used for active vibration isolation. From the experimental results of each algorithm, effective control algorithms for this active vibration-isolation system are proposed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.520-525
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• 2003

The determination of unknown parameters in rotating machinery is a difficult task and optimization techniques represent an alternative technique for parameter identification. The Simulated Annealing(SA) and Genetic Algorithm(GA) are powerful global optimization algorithm. This paper proposes new hybrid algorithm which combined GA with SA and local search algorithm for the purpose of parameter identification. Numerical examples are also presented to verify the efficiency of proposed algorithm. And, this paper presents the general methodology based on hybrid algorithm to identify unknown bearing parameters of flexible rotors using measured unbalance responses. Numerical examples are used to ilustrate the methodology used, which is then validated experimentally.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.85-87
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• 1998

In general, we apply the 2 dimensional method to analyze the characteristic of electric machinery. But it is very difficult to analyze the air-cored machine like as superconducting generator, because it have 3 dimensional flux distribution. In this paper, we compare the analysis r between 2D and 3D. 3D Finite Element Meth applied to the superconducting generator at n condition. And we studied the characteristic acc to the axial length of magnetic shield.

• Interaction and multiscale mechanics
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• v.3 no.1
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• pp.1-22
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• 2010

In this paper one introduces a method of multiscale modelling called collection of dynamical systems with dimensional reduction. The method is suggested to be an appropriate approach to theoretical modelling of phenomena in mechanics of materials having in mind especially dynamics of processes. Within this method one formalizes scale of averaging of processes during modelling. To this end a collection of dynamical systems is distinguished within an elementary dynamical system. One introduces a dimensional reduction procedure which is designed to be a method of transition between various scales. In order to consider continuum models as obtained by means of the dimensional reduction one introduces continuum with finite-dimensional fields. Owing to geometrical elements associated with the elementary dynamical system we can formalize scale of averaging within continuum mechanics approach. In general presented here approach is viewed as a continuation of the rational mechanics.

• Proceedings of the Safety Management and Science Conference
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• 1999.11a
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• pp.83-95
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• 1999

The half of injuries by carrying-unloading machinery was injuries due to crane. The purpose of this study was to analyze present condition of injuries by the crane, to investigate hazard management model, injury prevention technique, and to suggest safety countermeasures of crane working. The hazard management model is composed of 5 rules and 10 methods. The rules are to remove, separate, protect, make up and correspond. Prior to this crane countermeasures, general protection for head, foot and hand are needed. Hazard prevention affects on industrial management economically and psychologically. The preparation of safety countermeasures are very important for the prevention of industrial injuries. The countermeasures are setting-up of safety culture, active and rationale safety education. As the industrial safety and health system should be performed for the employees' health and life, the industrial competitive power and productivity would be improved.

• Molecules and Cells
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• v.43 no.3
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• pp.215-221
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• 2020

The olfactory bulb (OB) has an extremely higher proportion of interneurons innervating excitatory neurons than other brain regions, which is evolutionally conserved across species. Despite the abundance of OB interneurons, little is known about the diversification and physiological functions of OB interneurons compared to cortical interneurons. In this review, an overview of the general developmental process of interneurons from the angles of the spatial and temporal specifications was presented. Then, the distinct features shown exclusively in OB interneurons development and molecular machinery recently identified were discussed. Finally, we proposed an evolutionary meaning for the diversity of OB interneurons.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.346-352
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• 2003

The study was performed to search on alternative material for turbopump parts made of Russian material by analyzing and comparing chemical and mechanical material properties. Iron base material was generally used for turbopump. This material can be categorized into stainless steel and heat resisting steel by quantity of additional elements. Each steel was also classified into austenite steel, ferrite steel, and martensite steel. Alternative materials for turbopump inducer, impeller and casing are chosen by JIS SUS 631 and 321 as a result of this study. Because the material of Russian turbopump turbine may be developed by Russia itself, alternative material can be hardly found. However, Inconel 718 for turbine material is thought to be proper in the aspect of hardness considering general use of this material for turbopump turbine in Japan and France.

• KIEE International Transactions on Power Engineering
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• v.4A no.4
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• pp.201-206
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• 2004

With the advent of distributed generation, power systems in general are impacted in regards to stability and power quality. Distributed generation has positive impacts on system restoration following a fault, higher reliability, and mitigation of effect due to voltage sag. However, distributed generation also has negative impacts on the decrease of reliability such as changes of protective device setting and mal-operation. Because bulk power systems consist of various sources and loads, it is complicated to analyze power systems that have distributed generation. The types of distributed generation usually are classified as the rotating machinery system and the inverter-based system. In this paper, distributed generation is designed as a synchronous generator, and the distribution system with its distributed generation model is simulated using EMTP. In addition, this paper shows the simulation results according to the types of distributed generation

• Proceedings of the KIEE Conference
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• summer
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• pp.1223-1225
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• 2004

In difference with the rotary type electrical machinery, the linear induction motor(LIM) that generates the direct thrust directly, is widely used for the operation system of electrified railroad, elevation system, conveyer system, and so on. The operational principle of linear induction motor is constructively similar to the general rotary induction motor. It is difficult to realize the complicate linear induction motor which is applied SVPWM system, but widely used in vector motor control system or servo control system because of its high performance in current control. In this paper, we presented the dynamic characteristic analyzing methode, and calculated efficiently the end effect by using equivalent circuit methode in the operating linear induction motor control system for Maltlab simulink modeling.