• Proceedings of the KSR Conference
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• 2008.06a
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• pp.371-377
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• 2008

A design pattern is a general reusable solution to a commonly occurring problem in software design. A design pattern is not a finished design that can be transformed directly into code. It is a description or template for how to solve a problem that can be used in many different situations. Moreover, the name of pattern itself also can be a kind of common language among developers and patterns can be easily imported to various applications demanding similar requirements. In this paper, we present models of CBTC onboard system which follows ERTMS/ETCS specifications and present patterns applied to our system.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.216-222
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• 2003

Train control by radio based communication is one of the interesting new fields in train signal. The radio based control has more benefits, low headway and low construction and maintenance cost, than conventional control. In this paper, a safe and efficient train operation is introduced. Triple radio communications, train to train, train to station, and train to central traffic control, are used to increase the reliability. One of these communications channels has a fault; the others can take the functions of it. Absolute position of a train is transmitted to station via radio communication. In the station, the interlocking mechanism should be activated as the legacy.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.947-953
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• 2006

ATC on-board equipment require realtime embedded software with high level of safety and reliability. To satisfy these requirements, many techniques are applied to the development of software during the lifecycle. In case of software modeling, object-oriented methodology is widening its niche replacing traditional structured methodology and modeling in UML using a CASE tool is a growing trend. In this paper, we modeled ATC on-board software in UML using Rhapsody, which is a modeling tool for realtime embedded software. We modeled the behavior of ATC on-board equipment based on state machine diagram and validated the model using the animation feature provided in the tool. According to our study, the CASE tool based on UML showed high level of applicability in modeling and verifying the software with complex behavioral characteristics.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.59-60
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• 2008

In this paper, we investigate the ability of the ARM processor to implement an industrial controller with or without embedded operating system. Discrete-time PID controllers are implemented and tested under various settings e.g. cache on/off, different clock frequencies using S3C2410X chip. A method of real-time application of discrete-time PID controller in WinCE environment is proposed. Based on the test result, we provide the maximum sampling frequencies of PID controller using ARM processor.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.12
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• pp.1119-1124
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• 2013

In this paper we propose a novel torque control method for permanent magnet synchronous motors using the SVPWM (Space Vector PWM). The control law is described in the rotating d-q frame and is devised to track a given reference flux with which the reference torque is generated. The key feature of the proposed control is that it provides uniform dynamics with desired closedloop poles independent of the rotating speed and the desired poles can be selected to yield a fast response with only a small amount of torque ripple.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.2
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• pp.149-155
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• 2012

This paper provides an efficient model predictive control for the output voltage control of three-phase inverter system which includes output LC filters. Use of SVPWM (Space Vector Pulse-Width-Modulation) and the rotating d-q frame is made to obtain an input constrained dynamic model of the inverter system. From the measured/estimated output current and reference output voltage, corresponding equilibrium values of the inductor current and the control input are computed. Derivation of a feasible and invariant set around the equilibrium state is made and then a receding horizon strategy which steers the current state deep into the invariant set is proposed. In order to remove offset error, use of disturbance observer is made in the form of state estimator. The efficacy of the proposed method is verified through simulations.

• Journal of radiological science and technology
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• v.37 no.3
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• pp.177-185
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• 2014

This study focused on effects of patient exposure dose reduction with AEC (Auto Exposure Control) marker that is designed for showing location of AEC in X-ray Chest radiography. It included 880 adults who have to use Chest X-ray Digital Radiography system (DRS, LISTEM, Korea). AEC (Ion chambers are posited in top of both sides) are used to every adult and set X-ray system as Field size $17{\times}17inch$, 120kVp, FFD 180cm. 440 people of control group are posited on detector to include both sides of lung field and the other 440 people of experimental group are set to contact their lung directly to Ion chamber (making marker to shows location). Then, measured every DAP and, estimated patient effective dose by using PCXMC 2.0. The average age of control group (M:F=245:195) is 53.9 and the average BMI is 23.4. BMI ranges from under weight: 35, normal range: 279, over weight: 106 to obese: 20 and average DAP is 223.56mGycm2, Mean effective dose is 0.045mSv. The average age of experimental group (M:F=197:243) is 53.7 and the average BMI is 22.7. BMI ranges from under weight: 34, normal range: 315, over weight: 85 to obese: 6 and average DAP is 207.36mGycm2, Mean effective dose is 0.041mSv. Experimental group shows less Mean effective dose as 0.004mSv (9.7%) than control group. Also, patient numbers who got over exposure more than 0.056mSv (limit point to know efficiency of AEC marker) is 65 in control group (14.7%), 19 in experimental group (4.3%) and take statistics with t-Test. The statistical difference between two groups is 0.006. In order to use proper amount of X-ray in auto exposure controlled chest X-ray system, matching location between ion chamber and body part is needed, and using AEC marker (designed for showing location of ion chamber) is a way to reduce unnecessary patient exposure dose.