• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.834-836
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• 2009

The authors have been discussed the optimal voltage regulation method and on-line real time method using artificial neural networks in the distribution system interconnected with Distributed Generation and Storage(DSG) systems. However, these methods have difficulty in dealing with the random load variations and operation characteristics of a number of DSG systems. To overcome these problems, this paper shows the basic concepts of smart grid system which is considered as one of the power delivery system in the near future and presents an evaluation method on the impacts of customer voltages by the operation of smart grid system. The smart grid system can change the system configuration in a flexible manner by using the static switches and offer the different power qualities in power services through the power quality control centers.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1235-1239
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• 2003

On the base of network frame and protocol system of Ethernet the networked sensing technology based on Ethernet is studied and the design principles of industrial Ethernet measurement of control system is put forward, and the general structure model is built in the paper. An eight-bit economical MCU scheme is proposed, and a general scheme of distributed intelligent networked measuring and control equipment based on TCP/IP is designed too. A compact TCP/IP protocol stack are successfully implemented in eight-bit MCU. With C51 program language, method of modularized programming is applied in soft design. The problem of in-system modifying measuring and control strategy of its system is solved successfully by assigning memory dynamically and saving parameter with EEPROM, and it makes the intelligent networked measurement and control system can explain and analyses control strategy from PC. Experiment result shows that, the research of intelligent networked measurement and control equipment and system base on TCP/IP is successful, with flexible network, convenient usage, and good commonality.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2652-2654
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• 2005

A vacuum chamber temperature control system of Pohang Accelerator Laboratory (PAL) storage ring is a subsystem upgraded PAL control system, which is based upon Experimental Physics and Industrial Control System (EPICS) [1]. There are two control components, data acquisition system (SA120 data logger), development control system IOC (Input/Output Controller) at the storage ring of PAL. There are 240 vacuum chamber at the storage ring. It was a very important problem to solve how to monitor such a large number of vacuum chamber temperature distributed around the ring. The IOC connect MODBUS/JBUS field network to asynchronous serial ports for communication with serial device. It can simultaneously control up to 4 data acquisition systems. Upon receiving a command from a IOC running under Windows2k through the network, the IOC communicate through the slave serial interface ports to SA120. We added some software components on the top of EPICS toolkit. The design of the vacuum control system is discussed. This paper describes the development vacuum chamber temperature control system and how the design of this system.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.1
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• pp.108-117
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• 2007

For a PERT network the sensitivity analyses are valuable tools for effective management and control of a project. In a previous article, a method was developed for the sensitivity analysis of the expected project completion time (${\mu}_{T}$) with respect to the expected duration of an activity (${\mu}_{i}$) under the assumption that the durations of activities are independent and normally distributed. In the present article, a method is presented for the sensitivity analysis of ${\mu}_{T}$ with respect to ${\mu}_{i}$ when the durations of activities are independent and follow discrete distributions, which utilizes the previous sensitivity analysis method with modifications. The accuracy of the proposed method is assessed using various example PERT networks, and the computational results indicate that the accuracy is comparable to that of direct Monte Carlo simulation.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.5
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• pp.19-32
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• 2018

This study focuses on an M/M/1 queue with an attached continuous-type inventory. The customers arrive into the system according to the Poisson process, and are served in their arrival order; i.e., first-come-first-served. The service times are assumed to be independent and identically distributed exponential random variable. At a service completion epoch, the customer consumes a random amount of inventory. The inventory is controlled by the traditional (s, S)-inventory policy with a generally distributed lead time. A customer that arrives during a stock-out period assumed to be lost. For the number of customers and the inventory size, we derive a product-form stationary joint probability distribution and provide some numerical examples. Besides, an operational strategy for the inventory that minimizes the long-term cost will also be discussed.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.3
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• pp.29-33
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• 2016

Development of the distributed energy resources such as photovoltaic, wind, and fuel cell has increased rapidly due to the rising demand for clean energy utilization. On the other hand, the distribution system became complex and has problems such as degradation of power factor and current unbalance caused by power converters, reactive power and unbalanced loads. To solve these problems, this paper proposes a 3-phase 4-leg type power conditioning system with compensation control algorithm for the reactive power and unbalance current in distribution system using photovoltaic resource. It is simulated in PSCAD/EMTDC and the effectiveness is confirmed.

• Journal of the Korean Solar Energy Society
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• v.33 no.6
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• pp.70-76
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• 2013

Recently industrial control systems have been required to ensure intelligent, high tech automation, interconnection and interoperability demands. Therefore, there is a need to redefine the structure concepts of SCADA system for wind power. Also, at this time, the integrated management system is required for the distributed development of wind farms where are needed often interoperability features and exchange information between different wind farms, wind turbines or SCADA systems. In this paper, an integrated structural concepts for SCADA system are defined. Based on this definition of an integrated SCADA system, the basic designs are analyzed on physical layer, system layer and application layer which are corresponded to wind turbine controller, the SCADA server and the SCADA client, and implement HMI. Between the implementation SCADA server and the client, their normal functions were verified at the small scale wind energy test facilities.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.3
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• pp.87-94
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• 2012

This study investigates the relationship among locus of control, organizational justice, and job satisfaction. First, this study examines the conceptual structures of organizational justice through field study. Second, organizational justice influences job satisfaction. Third, locus of control influences organizational justice. Literature review identified four factors of organizational justice - distributive, procedural, interpersonal, and informational justice. These identified determinants are expected to have significant relationships with locus of control and job satisfaction. Questionnaires were distributed to 500 members of a manufacturing companies. Among returned questionnaires, 357 samples were used for empirical study. Structural equation analyses based on PLS (partial least square) method were employed to test the hypotheses and the model. The overall adequacy of fit was found to be acceptable. Confirmatory factor analyses supported a 4-factor structure of organizational justice. Distributive, procedural, interpersonal, and informational justice had significant positive effects on job satisfaction. In addition, the effects of locus of control had significant positive effects on organizational justice factors. The results of this study suggest that interpersonal and informational justice should be regarded as important factors of organizational justice to analyze the relationships between locus of control and job satisfaction as well as the relationships among the justice constructs.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.4
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• pp.71-79
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• 2011

This paper proposes a reliability enhancement of industrial real-time Ethernet using master redundancy method for NPPs(Nuclear Power Plants). In this paper, Ethernet Powerlink is investigated for distributed control systems for NPPs considering real-time and reliability performance. The proposed method can reduce a master switch-over time using PReq signal when Ethernet Powerlink master(Managing Node) failure was occurred. Using the OPNET simulation results, the performance enhancement of master switch-over time of Ethernet Powerlink is verified for NPPs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.561-564
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• 2014

The Rare Isotope Science Project (RISP) at the Institute for Basic Science (IBS) constructs the rare isotope accelerator facility in South Korea. Since the accelerator control system uses various Ethernet-based devices and equipment, it is essential to build a unified Network-based control system. Because of the complexity of the accelerator facility, it will be a challenge to install a device in a proper location where the device could react quickly and exactly with respect to network security. In this report, we will present early study on Simple Network Management Protocol (SNMP) that tests various Ethernet-based devices out on an ideal network configuration in order to find an optimal location for each Ethernet-based device. Moreover, we will discuss future plan to integrate SNMP into Experimental Physics and Industrial Control System (EPICS) that is distributed soft real-time control systems for scientific instruments such as a particle accelerators, telescopes and other large scientific experiments.