• International Journal of Advanced Culture Technology
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• 제1권2호
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• pp.18-23
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• 2013

In this paper, we consider the problem of designing optimal sensing time and the minimization of energy consumption in the Cognitive radio Network. Trade-off between throughput and the sensing time are observed, and the equations are derived for the optimal choice of design variables. In this paper, we also look at the optimization problem involving all the design parameters together. The advantages of the proposed scheme for the spectrum sensing and access process are shown through simulation.

• 한국전기전자재료학회논문지
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• 제23권3호
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• pp.240-244
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• 2010

The surface segregation and surface order near the order-disorder phase transition of FeCo alloy was studied through Monte Carlo simulation of an Ising type model Hamiltonian. The results showed that the proper choice of Hamiltonian parameters could reproduce the recent observation of surface order above the transition temperature and that the field term played dominant role.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.188-193
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• 1992

The PID controllers which is widely used in the process industry are poorly damped when the dynamic process contains significant dead time or when there are random disturbances acting on the plant. GPC is known to be more superior than conventional self-tuning algorithm in overcoming above problem and prior choice of model order. In this paper, we propose the method which determine the parameter of PID controller from minimization of GPC criterion. The controller has emplicit scheme which is comprised of parameter estimation and PID control design. Simulation results show the performance of the proposed self-tuning PID controller.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.106-111
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• 1992

The flexible arm has considerable structural flexibility. Because of its flexibility, the dynamic nodel is very complex and difficult to get. In this paper, fuzzy logic controller(FLC) of the single-link flexible arm is proposed, for FLC does not require any mathematical model of the plant. Noncolocated control is used and the choice of linguistic variables are examined. The simulation results are presented to show the possibility of FLC for flexible arm.

• Journal of the Korean Statistical Society
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• 제36권3호
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• pp.423-434
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• 2007

Imputation using a regression model is a method to preserve the correlation among variables and to provide imputed point estimators. We discuss the implementation of regression imputation using fractional imputation. By a suitable choice of fractional weights, the fractional regression imputation can take the form of hot deck fractional imputation, thus no artificial values are constructed after the imputation. A variance estimator, which extends the method of Kim and Fuller (2004), is also proposed. Results from a limited simulation study are presented.

• Communications for Statistical Applications and Methods
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• 제16권6호
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• pp.1047-1054
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• 2009

Local smoothing jump detection procedure is a popular method for detecting jump locations and the performance of the jump detector heavily depends on the choice of the bandwidth. However, little work has been done on this issue. In this paper, we propose the bootstrap bandwidth selection method which can be used for any kernel-based or local polynomial-based jump detector. The proposed bandwidth selection method is fully data-adaptive and its performance is evaluated through a simulation study and a real data example.

• Journal of the Korean Data and Information Science Society
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• 제19권4호
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• pp.1465-1476
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• 2008

In recent years wavelet methods have been focused on block shrinkage or thresholding approaches to accounting for the sparseness of the wavelet representation for an unknown function. The block shrinkage or thresholding methods have been developed in both of classical methods and Bayesian methods. In this paper, we propose a Bayesian approach to selecting wavelet basis functions at each resolution level without MCMC procedure. Simulation study and an application are shown.

• Smart Structures and Systems
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• 제14권6호
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• pp.1221-1245
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• 2014

Real-time hybrid simulation (RTHS) is a promising cyber-physical technique used in the experimental evaluation of civil infrastructure systems subject to dynamic loading. In RTHS, the response of a structural system is simulated by partitioning it into physical and numerical substructures, and coupling at the interface is achieved by enforcing equilibrium and compatibility in real-time. The choice of partitioning parameters will influence the overall success of the experiment. In addition, due to the dynamics of the transfer system, communication and computation delays, the feedback force signals are dependent on the system state subject to delay. Thus, the transfer system dynamics must be accommodated by appropriate actuator controllers. In light of this, guidelines should be established to facilitate successful RTHS and clearly specify: (i) the minimum requirements of the transfer system control, (ii) the minimum required sampling frequency, and (iii) the most effective ways to stabilize an unstable simulation due to the limitations of the available transfer system. The objective of this paper is to establish a stability switch criterion due to systematic experimental errors. The RTHS stability switch criterion will provide a basis for the partitioning and design of successful RTHS.

• 의학교육논단
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• 제13권2호
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• pp.47-57
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• 2011

Purpose: This study was conducted to explore the current usage of high integration mannequin human patient simulators (hereafter HPS) in nursing education. Methods: Thirty-two faculty members in 11 nursing schools participated in this survey. the questionnaire consisted of some multiple-choice questions and open questions to collect data on the experience of faculty members with using HPS as well as quantitative information. Results: The faculty members who used HPS in their classes recognized the need to use simulation in nursing education. They identified the advantages of simulation education as promoting adaptation to the clinical environment(46.9%), promoting self-confidence(28.1%), promoting critical thinking(28.15), and making direct nursing skill practice available(28.1%). However, they considered the obstacles to the use of simulation in nursing education to be insufficient manpower(62.5%), insufficient time(40.6%), and difficulty in preparing a teaching strategy(34.4%). Conclusion: HPS is useful in nursing education, but systematic plans and policies regarding on its operation are needed to confirm its effectiveness. The results of this study generally provide a basic information for use of HPS in nursing education.

• Journal of Advanced Marine Engineering and Technology
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• 제29권4호
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• pp.391-398
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• 2005

In this investigation, turbulent premixed combustion and flame front propagation in a gas turbine combustion chamber is studied. Direct numerical simulation of turbulent reacting flows demands extremely high computational resources, especially in more complicated geometry. The alternative choice may be left for Large Eddy Simulation (LES) by which only large scales are solved directly. In combustion problems, capturing the large scales' behavior without solving the details of small scales is a difficult task. Using a transport equation for description of the flame front propagation and therefore avoiding the calculation of inner flame structure is the basic idea of this study. For this purpose. the so-called G-equation has been used by which any iso-level of the G variable provides the flame location. A comparison with the experiment indicates that the present method can predict a turbulent velocity field and also capture a instantaneous 3-dimensional flame structure.