• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1337-1342
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• 1990

This paper deals with control system design strategy for electrolmaginetic suspension (E.M.S.) system. For a successful control of E.M.S. system, the nature of E.M.S. system is deeply studied in the view point of non-linear, open-loop unstable, time-varying, non-minimum phase system. To find a special control treatment for E.M.S. system, analyses and simulations for various models are carried out. As one of the successful candidates, adaptive control concept is introduced and sample hardware system using digital signal processor is implemented.

• Smart Structures and Systems
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• v.14 no.6
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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.

• Journal of Biosystems Engineering
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• v.21 no.1
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• pp.21-33
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• 1996

This study was to obtain basic information needed to develop the effective weed control method for the production of less polluted agricultural products by inducing viability loss of weed seeds in soil with infrared irradiation. Ceramic plates were heated by LPG with the aid of forced air and the infrared produced from plates was used as the heat source for heating soil. The soil heated in this study was sandy loam with four levels of moisture contents (0.5, 5.1, 9.1, 15.0% wb). The temperature distribution was measured at various soil depths when soil was irradiated with infrared for different irradiation time (30, 60, 90 sec). The soil depths with duration time of minimum 3 minutes over $80^circ C$, temperature inducing viability loss of weed seeds, were investigated. When the moisture content of soil was 0.5% and 5.1% wb, the soil depths which can induce viability loss of weed seeds was greatly increased with increasing irradiation time. When 30 seconds of irradiation time was applied on soil with moisture content of 9.1% or 15.0% wb, any depths of soil tested in this study was not reached to the temperature of 8$0^{\circ}C$. Generally, the soil depth being needed for viability loss of weed seeds was decreased with increasing moisture content of soil.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.39-42
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• 2014

The objective of this study was to estimate cardinal temperatures for germination of lettuce (Lactuca sativar L.) using bilinear, parabolic, and beta distribution functions. Seeds of lettuce were germinated in a growth chamber at 7 constant temperatures: 10, 14, 16, 20, 24, 28, and $32^{\circ}C$. Four replicates of 100 seeds were placed on two layers of filter paper in a 9 cm petri-dish. Radicle emergence of 1 mm was scored as germination. The time course of germination was modeled using a logistic function. These minimum, optimum, and maximum temperatures were estimated by regression of the inverse of time to 50% germination rate against the temperature gradient. In bilinear function, minimum, optimum, and maximum temperatures were $7.9^{\circ}C$, $23.3^{\circ}C$, and $28.0^{\circ}C$, respectively. In parabolic function, minimum, optimum, and maximum temperatures were $9.7^{\circ}C$, $19.5^{\circ}C$, and $29.4^{\circ}C$, respectively. In beta distribution function, minimum, optimum, and maximum temperatures were $3.7^{\circ}C$, $20.7^{\circ}C$ and $32.0^{\circ}C$, respectively. Minimum, optimum, and maximum ranges of temperatures were $3.7{\sim}9.7^{\circ}C$, $19.5{\sim}23.3^{\circ}C$, and $28.0{\sim}32.0^{\circ}C$, respectively.

• Journal of Environmental Impact Assessment
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• v.14 no.4
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• pp.157-164
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• 2005

Existing models that predict of Daily water supply include statistical models and neural network model. The neural network model was more effective than the statistical models. Only neural network model, which predict of Daily water supply, is focused on estimation of the operational control. Neural network model takes long learning time and gets into local minimum. This study proposes Neuro Genetic hybrid model which a combination of genetic algorithm and neural network. Hybrid model makes up for neural network's shortcomings. In this study, the amount of supply, the mean temperature and the population of the area supplied with water are use for neural network's learning patterns for prediction. RMSE(Root Mean Square Error) is used for a MOE(Measure Of Effectiveness). The comparison of the two models showed that the predicting capability of Hybrid model is more effective than that of neural network model. The proposed hybrid model is able to predict of Daily water, thus it can apply real time estimation of operational control of water works and water drain pipes. Proposed models include accidental cases such as a suspension of water supply. The maximum error rate between the estimation of the model and the actual measurement was 11.81% and the average error was lower than 1.76%. The model is expected to be a real-time estimation of the operational control of water works and water/drain pipes.

• The Korean Journal of Nuclear Medicine Technology
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• v.19 no.2
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• pp.81-86
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• 2015

Purpose This study was to evaluate the usefulness through the comparison of patients group and healthy control group by acquiring a variety of functional parameters index from time-activity curves of salivary gland scintigraphy using $^{99m}Tc$. Materials and Methods From December 2014 to February 2015 with the targets of 30 patients in the patient group who presented themselves with xerostomia and underwent the salivary gland scan and 10 people in healthy control group, approximately 30 minutes of dynamic Scan was carried out after the intravenous bolus injection of 370 MBq of $^{99m}TcO_4{^-}$ and per os stimulation with Vitamin C powder 20 minutes after the injection. The method of quantitative analysis was as follows, the time-activity curve was drawn after the parotid gland and submandible gland were prescribed as a region of interest, a variety of functional parameters index was obtained in each position of the curve, and the patients group and the control group were compared. Results As for the methods applied in comparison and measurement, uptake ratio (UR), time at maximum counts (Tmax), time at minimum counts (Tmin), maximum accumulation (MA), accumulation velocity, maximum secretion (MS), maximum stimulation secretion (MSS), and secretion velocity (SV) were used. In the comparison of functional parameters index of patient group and normal group, the healthy normal group showed significant difference compared to the patient group in all indices except for the minimum radioactivity time (Tmin), and also in terms of variation over time the normal group showed significant difference compared to the patient group (p<0.05). Conclusion Consequently, it was considered that the quantitative analysis that used a variety of functional parameters index would be useful for evaluating the function of the salivary glands of the patients with xerostomia as an objective and standardized information.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.3 s.246
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• pp.295-301
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• 2006

The wheel slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS systems. In order to achieve the superior braking performance through the wheel-slip control, real-time information such as the tire braking force at each wheel is required. In addition, the optimal target slip values need to be determined depending on the braking objectives such as minimum braking distance, stability enhancement, etc. In this paper, a robust wheel slip controller is developed based on the adaptive sliding mode control method and an optimal target slip assignment algorithm. An adaptive law is formulated to estimate the longitudinal braking force in real-time. The wheel slip controller is designed using the Lyapunov stability theory and considering the error bounds in estimating the braking force and the brake disk-pad friction coefficient. The target slip assignment algorithm is developed for the maximum braking force and searches the optimal target slip value based on the estimated braking force. The performance of the proposed wheel-slip control system is verified In simulations and demonstrates the effectiveness of the wheel slip control in various road conditions.

• International Journal of Automotive Technology
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• v.8 no.2
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• pp.211-217
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• 2007

The wheel slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS (Anti-lock Brake System) systems. In realizing the wheel slip control systems, real-time information such as the tire braking force at each wheel is required. In addition, the optimal target slip values need to be determined depending on the braking objectives such as minimum braking distance and stability enhancement. In this paper, a robust wheel slip controller is developed based on the adaptive sliding mode control method and an optimal target slip assignment algorithm is proposed for maximizing the braking force. An adaptive law is formulated to estimate the braking force in real-time. The wheel slip controller is designed based on the Lyapunov stability theory considering the error bounds in estimating the braking force and the brake disk-pad friction coefficient. The target slip assignment algorithm searches for the optimal target slip value based on the estimated braking force. The performance of the proposed wheel slip control system is verified in HILS (Hardware-In-the-Loop Simulator) experiments and demonstrates the effectiveness of the wheel slip control in various road conditions.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.2
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• pp.108-114
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• 1996

We present proofs of the stability and convergence of Self-organizing feature map (SOFM) neural network with time-invarient learning rate and binary reinforcement function. One of the major problems in Self-organizing feature map neural network concerns with learning rate-"Kalman Filter" gain in stochsatic control field which is monotone decreasing function and converges to 0 for satisfying minimum variance property. In this paper, we show that the stability and convergence of Self-organizing feature map neural network with time-invariant learning rate. The analysis of the proposed algorithm shows that the stability and convergence is guranteed with exponentially stable and weak convergence properties as well.s as well.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2725-2730
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• 2003

In this study we present a vibration controller for articulated robots that has flexible joints modeled as a 2-mass system. Most of articulated robots have time varying load inertias for each axis according to its motion. Moreover, the inertias vary drastically; for the base axis of articulated robots it may vary about 10 times of its minimum value. But, for industrial robots and many mechatronic devices, it is desirable to maintain control performance in spite of load inertia variation. So we propose a control gain adjustment rule considering the time-varying nature of load inertia. In this gain-adjusting algorithm, the pole locations are in proportion to the anti-resonance frequency of the 2-mass system. The simulation and experimental results show uniform properties in overshoot in spite of the variation of load.