• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.151.3-151
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• 2001

A design of PI controller to be used to control the first-order lag plus dead time process, such as a flow process, by the coefficient diagram method (CDM) is investigated. The factor of the dead time of process is first approximated to be the first-order by the Pade approximation. The response of the flow control system designed by CDM satisfy both transient and steady state specifications. However, the transient response generally still has long rise time. In order to improve the speed of the system response, a feedforward controller (FFC) is added into the PI control system. The structure of the FFC is a phase lead structure with two designed parameters and one derivative time obtained from the reaction curve of the flow process ...

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.228-234
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• 2006

This paper describes a systematic process which can generate a complete circuit specification efficiently for a given recursive DSP algorithm based on an optimal multiprocessor scheduler. The process is composed of two states: scheduling and circuit synthesis. The scheduling part accepts a fully specified flow graph(FSFG) as an input, and generates an optimal synchronous multiprocessor schedule. Then the circuit synthesis part translates the modified schedule into a complete circuit diagram including a control specification. The circuit diagram can be applied to a silicon compiler for VLSI layout generation. This paper illustrates the whole process with an example of a second order Gray-Market lattice filter.

• Korean System Dynamics Review
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• v.14 no.3
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• pp.25-49
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• 2013

As global competition for green car, that is environmentally friendly car, is getting tougher, the governments and the related industries are putting their core efforts in its diffusion. However, the green car sales are disappointing so far. To overcome the gridlock, it is necessary to develop concrete analytical framework to understand the diffusion process. Based on causal loop analysis from the previous work, we have identified main variables and relationships of them in the diffusion process and developed a stock-flow diagram and mathematical formula for the main components. The model would be applied for further quantitative simulation on the diffusion process of green car and other innovative goods as well. Also, we have suggested constructive insights for the policy makers and for the related industries. First, it is important to increase consumers' willingness to consider through marketing and word of mouth to accelerate the diffusion process. Second, in the perspective of the industry, the market share of green car should be increased at the earliest possible stage and this could be done by enhancing each components of green car attractiveness(e.g. price, driving range, social infra). Third, companies should develop a balanced investment between consumer and technology sector through a flexible financial policy. Fourth, the government continuously has the role of investing in the related R&D and social infra building. We expect the green car diffusion model and related formula from the research can provide meaningful tools to analyze the diffusion process of other new and innovative goods based on its deep researched literature review.

• IE interfaces
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• v.18 no.4
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• pp.465-476
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• 2005

Evolutionary operation is a useful tool for improving full-scale manufacturing process by systematically changing the levels of the process variables without jeopardizing the product. This paper presents a system design for the evolutionary operation software called 'evolutionary optimizer'. Evolutionary optimizer consists of four modules: factorial design, many variables, mixture, and mean/dispersion. Context diagram, data flow diagram and entity-relationship modelling are used to systematically design the evolutionary optimizer system.

• Journal of the Korean Operations Research and Management Science Society
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• v.21 no.3
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• pp.175-195
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• 1996

In conventional analysis methods, data and process are loosely coupled for building information systems. Several object oriented approaches have been proposed to integrate data and process. However, object oriented analysis requires a radical paradigm and thus system analysts find difficulties in generating object models direcctly from end users. To alleviate these difficulties, this paper proposes a methodology for deriving an object model by using structured analysis results. Objects are obtianed primarily from entities in Entity-Relationship Diagram. Methods are obtained through the analysis of the relationship between processes and data stores in Data Flow Diagram Methods are assigned to the objects by using object/process matrices. A real-life case is illustrated to demonstrate the usefulness of the methodology.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.134-136
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• 2007

Sequential Function Chart(SFC) is very easy to grasp the sequential flow of control logic and has the compatability for a maintenance, In process control, when an error is occurred, to execute other routine by force, we control the process by remote control. In this paper, we proposed the method of select sequence control by remote control in process control designed by Sequential Function Chart(SFC).

• Journal of the Korea Society for Simulation
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• v.22 no.4
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• pp.109-118
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• 2013

This paper adopts the system configuration to assess the reliability instead of making a fault tree (FT), which is a traditional method to analyze reliability of a certain system; this is the reliability block diagram (RBD) method. The RBD method is a graphical presentation of a system diagram connecting the subsystems of components according to their functions or reliability relationships. The equipment model for the reliability simulation is modeled based on the discrete event system specification (DEVS) formalism. In order to make various alternatives of target system, this paper also adopts the system entity structure (SES), an ontological framework that hierarchically represents the elements of a system and their relationships. To enhance the calculation time of reliability analysis, GPU-based accelerations are adopted to the reliability simulation.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.12
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• pp.1269-1280
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• 1990

Owing to the need to accommodate the load variation, thermal power plants need a modern controller in order to achieve better frequency regulation, faster response and higher efficiency. For a successful development of the digital instrumentation and control system that can adopt advanced control algorithms, power plant simulator must be available for safe and convenient test. In this paper, a simple drum-type boiler model is proposed using Signal Flow Diagram that describes the system by a combination of basic time responses representing the relationships between cause and effect process variables. After verifying the model and thereafter building a simulator based on the proposed model, we tested the operation of the controller and stability or efficiency of the implemented control algorithms.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.101-107
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• 2007

Assembly is mentioned as important process saving time and cost where we produce the machine with many parts relationships. In this study, parts assembly relationship is analysed for assembly information of micro milling machine which have been developing for research. Liaison diagram, datum flow chain and assembly tree are applied to discuss assembly characteristics of micro milling machine model. We can find out the characteristics of micro machine assembly and discuss about facility of assembly. Some analysis in this paper about micro milling machine will give a useful tools for assembly. We knew that the predicted results from analysis in this study are alignment and clearance among the parts. The 3D model of micro machine which is studied in this paper is not a complete model. Main parts of a micro milling machine are used and presented.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.194-199
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• 1990

Because of being operated to accomodate the load variation, fossile power plants need modern controller to satisfy frequency regulation, fast response and efficiency requirement. But in the way of developing the Digital Instrumentation and Control System that can adopt advanced control algorithms, power plant simulator must be available for safe and convenient test. In this paper, a simple drum-type boiler model is proposed, using Signal Flow Diagram that describes the system by a collection of basic time response representing the relationship between process variables. After verifying the model and thereafter building simulator based on the proposed model, we test the operation of controller and approve stability or efficiency of implemented control algorithms.