• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.2
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• pp.57-59
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• 2001

We investigated the maximum controllable current characteristics of the CB-BRT (Corrugated p-Base-Base Resistance Controlled Thyristor), which suppresses the snap-back effectively and increases the maximum controllable current(MCC) by employing the corrugated p-base. Experimental result shows that, when compared with conventional BRT, the MCC of the CB-BRT exhibits good stability on various process parameters. The MCC of the CB-BRT is larger than that of the conventional BRT by 50%, and the variation of the MCC in CB-BRT, caused by variation of the process parameters, is only 20% of that of the conventional BRT.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.4
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• pp.1-8
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• 2004

Various controllable parameters of an experiment have influence on grinding process. In order to get good products with a high quality, these parameters should be considered whether each parameter has relations to the quality. This paper describes the use of the design of experiments to minimize geometric error in surface grinding. Controllable parameters for the design of experiments were selected as spindle speed, table speed, depth of cut and grain size. From the experimental results, a degree of influence between these parameters and the geometric error was evaluated. An optimal set of grinding conditions was obtained by means of analysis of variance(ANOVA).

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.753-756
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• 1991

This paper aimed to analyse dose sensitivity to the controllable parameters of in-door radon $(^{222}Rn)$ and its decay products(Rn-D) by applying the input-output linear system theory. Physical behaviors of $^{222}Rn$ & Rn-D were analyzed in terms of $^{222}Rn$ gas generation, -migation and - infiltration to indoor environments, and the performance output-function(i.e. mean dose equivalent to Tracho-Bronchial(TB) lung region was assessed to the following ranges of the controllable parameters; a) the ventilation rate constant $({\lambda}_v)$ : $0{\sun}500[h^{-1}]$. b) the attachment rate constant$({\lambda}_a)$ : 0-500 $[h^{-1}]$. c) deposition rate constant $({\lambda}{_{d}^{u}})$: 0-50$[h^{-1}]$. A linear input-output model was reconstructed from the original models in literatures, as follows, which was modified into the matrices consisting of 111 nodal equations. a) indoor ${222}Rn$ & Rn-D Behaviour: jacobi- Porstendorfer- Bruno model. b) lung dosimerty : Jacobi-Eisfeld model. Some of the major findings, which identify the effectiveness of this model, were as follows. a) ${\lambda}_v$ is most effective, dominant controllable parameters in dose reduction, if mechanical ventilation is applied. b) ${\lambda}_v$, depending on the air particle-concentration, reduces the dose somewhat within ${\lambda}_v$<1 $h^{-1}R range. However, the dose increases conversely, ${\lambda}_v$>1 $h^{-1}R range range. c) ${\lambda}{_{d}^{4}}$ reduces the dose linearly as ${\lambda}_v$ dose. Such dose(z-axis) sentivities are shown with three-dimensional plots whoes x,y-axes are combined 2out the 3 parameter${\lambda}_v{\lambda}_s,\;{\lambda}_d^s$.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.500-505
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• 2009

This paper presents temperature control of engine cooling system using a controllable magnetorheological (MR) fan clutch. An appropriate size of MR fan clutch is devised and modeled on the basis of Bingham model. Subsequently, an optimization to determine design parameters such as width of housing is undertaken by choosing the reciprocal of the controllable torque as an objective function. Under consideration of spatial limitation, design parameters are optimally determined using finite element analysis. A sliding mode controller is then designed to control the angular velocity of the MR fan clutch using experimentally determined parameters. The designed controller is experimentally implemented and control performances of the MR fan clutch system are evaluated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.1
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• pp.51-57
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• 2010

This paper presents temperature control of engine cooling system using a controllable magnetorheological(MR) fan clutch. An appropriate size of MR fan clutch is devised and modeled on the basis of Bingham model. Subsequently, an optimization to determine design parameters such as width of housing is undertaken by choosing the reciprocal of the controllable torque as an objective function. Under consideration of spatial limitation, design parameters are optimally determined using finite element analysis. A sliding mode controller is then designed to control the angular velocity of the MR fan clutch using experimentally determined parameters. The designed controller is experimentally implemented and control performances of the MR fan clutch system are evaluated.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.148-154
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• 2000

In this study, the static and the dynamic characteristics of the load-sensitive hydraulic pump control systems of a hydraulic excavator were analyzed using the developed analysis tool. The results were compared with the experimental ones. To improve the static performance of the system, the system parameter effects on the controllable region and the pump pressure variation were studied. The parameters enhancing dynamic characteristics were also considered.

• Journal of Energy Engineering
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• v.15 no.1 s.45
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• pp.67-73
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• 2006

A calculation method on performance impact of the controllable operations parameter such as GT inlet filter ${\Delta}P$, compressor efficiency, and condenser pressure was devised to achieve best performance of combined cycle power plant with the on-line performance monitoring system. This method calculates the performance impact on the deviation between 'Expected' values and 'Actual' values. Controllable parameter targets are determined based on achievable performance given existing equipments and control conditions.

• Structural Engineering and Mechanics
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• v.73 no.1
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• pp.65-73
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• 2020

The present work describes a new time marching procedure for structural dynamics analyses. In this novel technique, time integration parameters are automatically evaluated according to the properties of the model. Such parameters are locally defined, allowing the user to input a numerical dissipation property for each element, which defines the amount of numerical dissipation to be introduced. Since the integration parameters are locally defined as a function of the structural element itself, the time marching technique adapts according to the model, providing enhanced accuracy. The new methodology is based on displacement-velocity relations and no computation of accelerations is required. Furthermore, the method is second order accurate, it has guaranteed stability, it is truly self-starting and it allows highly controllable algorithm dissipation in the higher modes. Numerical results are presented and compared to those provided by the Newmark and the Bathe methods, illustrating the good performance of the new time marching procedure.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.405-412
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• 1992

The problem we consider in this paper is more demanding than the problem of input-output linearization with state equivalence recently solved by Cheng, Isidori, Respondek, and Tarn. We request that the MIMO nonlinear system, for which the problem of input-output linearization with state-equivalence is solvable, can be decoupled. In exchange for further requirement like this, our problem produces more usable and informative results than the problem of input-output linearization with state-equivalence. We present the necessary and sufficient conditions for our problem to be solvable. We characterize each of the nonlinear systems satisfying these conditions by a set of parameters which are invariant under the group action of state feedback and transformation. Using this set of parameters, we can determine directly the unique one, among the canonical forms of decouplable and controllable linear systems, to which a nonlinear system can be transformed via appropriate state feedback and transformation. Finally, we present the necessary and sufficient conditions for our problem to be solvable with internal stability, that is, for stable decoupling.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.20 no.2
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• pp.51-65
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• 2016

Objectives This study was conducted to suggest a standard operating procedure (SOP) in order to improve the reliability of tongue-image analysis system. Methods An affecting-factors list was made, which may affect the diagnostic parameters of the tongue-image analysis system. They were sub-classified into two groups: controllable and uncontrollable. Only the controllable factors, which could affect the results and easily set-up, were included into the SOP draft. Affecting factors control experiment was performed to investigate the effects of controllable factors, whose influence on diagnostic parameters of the tongue-image analysis system is ambiguous: rehearsal for tongue extrusion; alignment of camera axis; and presentation of a guideline. Three subjects volunteered for this experiment. Each of three variables was implemented twice in a random order by two operators on the subjects. Finally, 96 tongue images obtained in the aggregate. The diagnostic parameter set as a primary outcome in this experiment was the percentage of tongue coating. Results All of the control variables were not significant in both operators; however, the presentation of a guideline was relatively more affect than two other variables. Interaction effects among the variables were also insignificant. Therefore, the presentation of a guideline was included in the final SOP and the other variables were not included. Conclusions We suggested the SOP which could be used for both experimenter and subject. Moreover, Each of the SOPs applied to various types of tongue-image analysis system should be developed in order to improve the reliability.