• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10C
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• pp.1370-1377
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• 2004

Optimal control gain for time-delay systems is made by an optimal control gain for delay-free systems multiplied by a state transition function for the delay time. The optimal control gain for delay-free systems is obtained by pushing two zeros of the PID controller closely to a larger pole of the second order plant. Thus the optimal tuning of PID controller for time-delay second order system is able to be obtained by calculation for the state transition function.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.107.4-107
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• 2001

In this paper, the guaranteed stability margins of LQ optimal regulators for a performance index with cross-product terms are suggested in the discrete-time case. An example for the LQ optimal regulator of an inverted pendulum system is given to demonstrate the validity of the suggested stability margins.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.45-48
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• 1986

In this paper, time optimal positioning control of the robotic manipulator is discussed. The equations for dynamic model of the robotic manipulator are nonolinear, and each link is highly coupled. A feedback linearizing and decoupling transformation makes the dynamic model linearized and decoupled, and optimal control input for the linear and decoupled system is derived.

• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.29-33
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• 2017

In order to solve this sort of electrostatic failure in Display and Semiconductor process, Soft X-ray ionizer is mainly used. Soft X-ray Ionizer does not only generate electrical noise and minute particle but also is efficient to remove electrostatic as it has a wide range of ionization. There exist variable factors such as type of tungsten thickness deposited on target, Anode voltage etc., and it takes a lot of time and financial resource to find optimal performance by manufacturing with actual X-ray tube source. Here, MCNPX (Monte Carlo N-Particle Extended) is used for simulation to solve this kind of problem, and optimum efficiency of X-ray generation is anticipated. In this study, X-ray generation efficiency was compared according to target material thickness using MCNPX and actual X-ray tube source under the conditions that tube voltage is 5 keV, 10 keV, 15 keV and the target Material is Tungsten(W). At the result, In Tube voltage 5 keV and distance 100 mm, optimal target thickness is $0.05{\mu}m$ and fastest decay time appears + decay time 0.28 sec. - deacy time 0.30 sec. In Tube voltage 10keV and distance 100 mm, optimal target Thickness is $0.16{\mu}m$ and fastest decay time appears + decay time 0.13 sec. - deacy time 0.12 sec. In the tube voltage 15 keV and distance 100 mm, optimal target Thickness is $0.28{\mu}m$ and fastest decay time appears + decay time 0.04 sec. - deacy time 0.05 sec.

• Journal of Korean Academy of Nursing
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• v.42 no.5
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• pp.730-737
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• 2012

Purpose: This study was done to identify the time interval to pressure ulcer and to determine the optimal time interval for position change depending on pressure ulcer risk in patients using foam mattress in intensive care units. Methods: The Braden scale score, occurrence of pressure ulcers and position change intervals were assessed with 56 patients admitted to an intensive care unit from April to November, 2011. The time to pressure ulcer occurrence by Braden scale risk group was analyzed with Kaplan-Meier survival analysis and log rank test. Then, the optimal time interval for position change was calculated with ROC curve. Results: The median time to pressure ulcer occurrence was 5 hours at mild or moderate risk, 3.5 hours at high risk and 3 hours at very high risk on the Braden scale. The optimal time interval for position change was 3 hours at mild and moderate risk, 2 hours at high and very high risk of Braden scale. Conclusion: When foam mattresses are used a slight extension of the time interval for position change can be considered for the patients with mild or moderate pressure ulcer risk but not for patients with high or very high pressure ulcer risk by Braden scale.

• Korean Journal of Veterinary Service
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• v.15 no.1
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• pp.1-6
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• 1992

A survey on the dosage optimal time for the bovine fascioliasis was carried out from Jan. 1987 to Dec. 1990. The results were summarized as follows ; 1. The mean infection rate was 27.7% (1,662 heads were infected out of 3,247 heads In 205 herds). A seasonal infection rate was winter (34.6%) >spring(32.5%) >summer(24.7%) > autumn(22.8%) 2. In the density of the fasciola spp. egg of infected bovine feces remarks 79.6% on the range below 10. 3. The density of fasciola spp. egg is not directly proportinal to the infection rate, and remarks on the range from 5 to 20. 4. In the herds dosed vermifuge the appearance of the fasciola spp. egg is as follows ; 1∼3 months show 3.8% and 4∼6 months 8.5% 5. The dosage optimal time for the bovine fasciliasis is as follows ; 1) According to the monthly infection rate the first dosage optimal time is Dec and Feb and the second-Jun and Aug. 2) In the herd dosed vermifuge the dosage optimal time is to dose twice by 60 days interval after 3∼4 months from previous dosage.

• Journal of Ocean Engineering and Technology
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• v.19 no.1 s.62
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• pp.87-94
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• 2005

This paper investigates the constant-level luffing and time optimal control of jib cranes. The constant-level luffing, which is the sustainment of the load at a constant height during luffing, is achieved by analyzing the kinematic relationship between the angular displacement of a boom and that of the main hoist motor of a jib crane. Under the assumption that the main body of the crane does not rotate, the equations of motion of the boom are derived using Newton's Second Law. The dynamic equations for the crane system are highly nonlinear; therefore, they are linearized under the small angular motion of the load to apply linear control theory. This paper investigates the time optimal control from the perspective of no-sway at a target point. A stepped velocity pattern is used to design the moving path of the jib crane. Simulation results demonstrate the effectiveness of the time optimal control, in terms of anti-sway motion of the load, while luffing the crane.

• Journal of the Korea Society of Computer and Information
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• v.14 no.7
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• pp.1-8
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• 2009

In this paper, make a study decision problem called an optimal release policies after testing a software system in development phase and transfer it to the user. The optimal software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement is generally accepted. The Bayesian parametric inference of model using log Poisson execution time employ tool of Markov chain(Gibbs sampling and Metropolis algorithm). In a numerical example by T1 data was illustrated. make out estimating software optimal release time from the maximum likelihood estimation and Bayesian parametric estimation.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2528-2533
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• 2007

Thermoforming is one of the most versatile and economical processes available for the manufacturing polymer products. The drawback of thermoforming is difficult to get uniform thickness of final products. For the distribution of thickness strongly depends on the temperature distribution of sheet, the adjustment of heater power is very important In this paper, an optimization study for getting uniform temperature distribution was carried out using dual optimization steps. At first, the steady state optimal distribution of heater power is searched by numerical optimization to get uniform temperature of sheet surface. In the second step, time-dependent optimal heater inputs have been found out to decrease the temperature difference through the direction of thickness using Rseponse Surface Method and D-optimal method. The optimization results show that the time-dependent optimal heater power distribution gives acceptable uniform sheet temperature in the field of forming temperature..

• The Journal of Fisheries Business Administration
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• v.23 no.2
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• pp.53-67
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• 1992

It has been recognized, virtually from the time of its inception, that fisheries economics, like other aspects of resource economics, should ideally be cast in capital-theoretic terms. The fish population or biomass can be viewed as a capital stock in that, like conventional or man-made capital, it is capable of yielding a sustainable consumption flow through time. This study is to introduce the optimal control theory which was extended from the theory of calculus of variations into the study of former static theory of fisheries economics started by Gordon (1954). The optimal control theory eliminated the inadequacies of the classical techniques to a large extent. From this point of view, this study, on the base of Schaefer model, summerizes most of major results achieved so far, but does so in a manner such that the links with capital theory are made transparent. This study explores two sets of problems. The first concerns the optimal approach to the equilibrium stock, i.e. the optimal investment policy. The second set of problems arises from the relaxation of the highly restrictive assumption of autonomy (i.e. the assumption that the parameters are independent of time), then concludes the relaxation of linearity assumption together with the complexities caused by that.