• 소음진동
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• 제9권1호
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• pp.97-102
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• 1999

Structure-borne noise is an important aspect to consider during the design and development of a vehicle. In this work. it was desired to identify the primary paths associated with structure-borne noise generated from the engine and front suspension. An experimental source-path-receiver model was used to characterize the system. A variety of primary sources such as engine. tires or exhaust system generate vibrations of the inner surfaces of the passenger compartment of a vehicle which subsequently radiate noise. The source was characterized by the force acting at the engine-to-body interface. and the path was characterized by pressure over force FRF's. The excitation forces were indirectly determined using dynamic stiffness of rubber mount or the system accelerance matrix. Through these analysis, path contribution diagram which is well expressed primary noise path is obtained.

• 한국자동차공학회논문집
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• 제3권6호
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• pp.78-86
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• 1995

The structure of premixed turbulent flames in a constant-volume vessel was investigated using a microprobe method. The flame potential signal having one to eight peaks was detected in the case of turbulent flames, each of them being regarded as a flamelet existing in the flame zone. Based on this consideration, the flame propagation speed, the thickness of the flame zone, the number of flamelets and the separation distance between adjacent flamelets in the flame zone were measured. The experimental resuits of this work suggest the existence of "reactant islands" behind the flame front when the turbulence was intensified to some extent. The critical(lowest) ratio of turbulence intensity to the laminar burning velocity being found to be about 0.7 for the formation of reactant islands in this experiment.

• 한국지능시스템학회논문지
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• 제3권1호
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• pp.23-28
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• 1993

Activity structures are a set of functional structures which may be used to provide a uniform framework for the description of information processing systems. The interaction of some aspects of activity structures is discussed. Intelligent systems, a subset of information handling systems, are the primary emphasis of this work. An extension to the functional structures of the activity structures is proposed. The proposed structure is a met a-structure which affects most elements of an intelligent system. The structure is concerned with describing the way uncertainty in an environment is handled by a system. An example is given which shows the importance of describing the uncertainty handling method(s) of an intelligent system.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.25-32
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• 2011

The objective of present work is to use numerical simulation to investigate the complex three-dimensional and secondary flow structures developed at the inlet and impeller in a centrifugal pump at design and off-design points. The pump impeller is shrouded with 6 backward swept blades and with a specific speed of 0.8574. The characteristic of the pump is measured experimentally with straight and curved intake sections. Numerical computation is carried out to investigate the pump inlet flow structures and subsequently the flow field within the centrifugal pump. The numerical results showed that strong interaction between the impeller eye and intake section. Secondary flow structure occurs upstream at the pump inlet has great influence on the pump performance and flow structure within the impeller.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1874-1876
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• 2004

Quantitative structure activity relationship has been probed for spirosuccinimide-fused tetrahydropyrrolo[1,2-a]pyrazine-1,3-dione derivatives acting as aldose reductase inhibitors. While the spirosuccinimide compounds contain a chiral center, the aldose reductase inhibition assay was performed with racemic mixtures in the published work. As the physicochemical descriptors of the QSAR analysis must be evaluated for a definite molecular structure, we devise a new 'racemic' descriptor as the arithmetic mean of the (R)-enantiomer descriptor and the (S)-enantiomer descriptor. The resultant QSAR model derived from the racemic descriptors outperforms the original QSAR models, closely reproducing the observed activity of optically pure enantiomers as well as racemic mixtures.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.495-495
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• 2000

The Stewart platform manipulator is a closed-kinematis chain robot manipulator that is capable of providing high st겨ctural rigidity and positional accuracy. However, this is a complex structure, so controllability of the system is not so good. In this paper, it introduces a new robust motion control algorithm using partial state feedback for a class of nonlinear systems in the presence of modelling uncertainties and external disturbances. The major contribution of this work introduces the development and design of robust observer for the slate and the perturbation w.hich is integrated into a variable structure controller(VSC) structure. The combination of controller/observer gives rise to the robust routine called sliding mode control with sliding perturbation observer(SMCSPO). The optimal gains of SMCSPO are easily obtained by genetic algorithm. Simulation and experiment are presented in order to apply to the stewart platform manipulator. There results show highly' accuracy and performance.

• Earthquakes and Structures
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• 제24권2호
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• pp.91-96
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• 2023

In this article, the vibration response of elastic nanocomposite beams with enhanced damping by nanoparticles is presented based on the mathematical model. Damp construction is considered by spring and damper elements based on the Kelvin model. Exponential shear deformation beam theory (ESDBT) has been used to model the structure. The mixed model model is used to obtain the effective properties of the structure including compaction effects. Using the energy method and Hamilton's principle, the equations of motion are calculated. The beam frequency is obtained by analytical method. The purpose of this work is to investigate the effect of volume percentage of nanoparticles and density, length and thickness of the beam on the frequency of the structure. The results show that the frequency increases with the increase in volume percentage of nanoparticles.

• Smart Structures and Systems
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• 제4권1호
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• pp.47-66
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• 2008

The present work utilizes system identification technique for health monitoring of shear building, wherein Parametric State Space modeling has been adopted. The method requires input excitation to the structure and also output acceleration responses of both undamaged and damaged structure obtained from numerically simulated model. Modal parameters like eigen frequencies and eigen vectors have been extracted from the State Space model after introducing appropriate transformation. Least square technique has been utilized for the evaluation of the stiffness matrix after having obtained the modal matrix for the entire structure. Highly accurate values of stiffness of the structure could be evaluated corresponding to both the undamaged as well as damaged state of a structure, while considering noise in the simulated output response analogous to real time scenario. The damaged floor could also be located very conveniently and accurately by this adopted strategy. This method of damage detection can be applied in case of output acceleration responses recorded by sensors from the actual structure. Further, in case of even limited availability of sensors along the height of a multi-storeyed building, the methodology could yield very accurate information related to structural stiffness.

• 한국병원경영학회지
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• 제23권3호
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• pp.63-71
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• 2018

The purpose of this study is to explore how the organizational structure of hospitals affects the pattern of conflicts between human resources at hospitals and then to present basic data necessary for conflict resolution. Research data were collected from the personnel of 14 hospitals in P city in Korea. The findings of the study are summed up as follows. First, administrative workers and with fewer years of service thought of the organizational structure as organic. Second, organizational conflict was found to be higher in those at older ages, with more years of service and in middle management positions. Next, as for conflict patterns between occupation types, nurses showed more conflicts with doctors and administrative workers, while administrative workers and public health personnel had more conflicts with nurses. Last, of the organizational structure factors, 'Subdivision of work,' 'Decision making method,' 'Opinion collection process,' 'Codification of responsibilities and rights' and 'Documentation of duties' were found to have negative effects on conflict patterns. Therefore, the findings imply that for decrease in organizational conflicts, hospitals need to be reorganized to have a more organic structure and take such differentiated measures for conflict resolution that consider characteristics of human resources, such as one's age, years of service and position.

• 한국사회복지학회:학술대회논문집
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• 한국사회복지학회 2005년도 춘계학술대회자료집
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• pp.387-411
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• 2005

The purpose of this article is to analyse the expenditure structure of the welfare mix; in order to grasp the holistic feature of the Korean social welfare. Most of all, the article attempts to elaborate the estimation methods of social welfare expenditure by including the components from which has been excluded so far - indirect tax expenditure of the government, nursery payments of households, life insurance pay-outs for survivors, inter-household private income transfers and the value of caring work of the family. In so doing, the article estimates that the total social welfare expenditure including state, enterprise, market, NPOs and family reached at 24.7% of GDP in 2000, which is approximately 2.5 times more than public social welfare expenditure. It implies that non-state, private sectors dominates the structure of social welfare provisions in Korea. In addition, based on the analyses of the expenditure structure, the article defines the main feature of Korea's welfare mix as the 'mixed structure of the welfare mix dominated by the protective family', or 'expanded public sector, relatively limited market, and protective family'. Such a family-dominated welfare mix structure in Korea indicates that the fundamental source of solidarity of the Korean social welfare system is family and, therefore, the welfare regime of Korea can be classified as 'Conservative'.