• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.244-245
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• 2013

This paper proposes a control algorithm for permanent magnet synchronous generator with a back-to-back three-level neutral-point clamped voltage source converter in a medium-voltage offshore wind power system under unbalanced grid conditions. The proposed control algorithm particularly compensates for the unbalanced grid voltage at the point of common coupling in a collector bus of offshore wind power system. This control algorithm has been formulated based on the symmetrical components in positive and negative rotating synchronous reference frames under generalized unbalanced operating conditions. Instantaneous active and reactive power are described in terms of symmetrical components of measured grid input voltages and currents. Negative sequential component of ac input current is injected to the point of common coupling in the proposed control strategy. The amplitude of negative sequential component is calculated to minimize the negative sequential component of grid voltage under the limitation of current capability in a voltage source converter. The proposed control algorithm makes it possible to provide a balanced voltage at the point of common coupling resulting in the generated power of high quality from offshore wind power system under unbalanced network conditions.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.491-494
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• 2019

The results from the analysis of recent security breach cases of industrial control systems revealed that most of them were caused by the employees of a partner company who had been managing the control system. For this reason, the majority of the current company security management systems have been developed focusing on their performances. Despite such effort, many hacking attempts against a major company, public institution or financial institution are still attempted by the partner company or outsourced employees. Thus, the institutions or organizations that manage Industrial Control Systems (ICSs) associated with major national infrastructures involving traffic, water resources, energy, etc. are putting emphasis on their security management as the role of those partners is increasingly becoming important as outsourcing security task has become a common practice. However, in reality, it is also a fact that this is the point where security is most vulnerable and various security management plans have been continuously studied and proposed. A system that enhances the security level of a partner company with a Virtual Desktop Infrastructure (VDI) has been developed in this study through research on the past performances of partner companies stationed at various types of industrial control infrastructures and its performance outcomes were statistically compiled to propose an appropriate model for the current ICSs by comparing vulnerabilities, measures taken and their results before and after adopting the VDI.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.1
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• pp.139-148
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• 2008

Information technology have led to change the automation of large industrial control system as well as business system and environments. Industrial control system(ICS) is vital components of most nation's critical infrastructures such as electricity, natural gas, water, waste treatment, transportation and communication that are based of national security, safety of citizen and development of national economy According to the change of business environment, organizational management pushed integration all of the system include MIS and ICS. This situation led to use standard information technologies for ICS, this transition has been to expose ICS to the same vulnerabilities and threats that plague business system. Recently government obliged owners of the public information system to audit for safety, efficiency and effectiveness, and also obliged the owners of national infrastructure to improve their system security as a result of vulnerability analysis. But there doesn't prepare a security architecture and information security auditing framework of ICS fur auditing. In this paper, I suggested the security architecture and information security auditing framework for ICS in order to prepare the base of industrial system security auditing.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.31
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• pp.33-42
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• 1994

This paper aims to analyse and appraise the effect of human performance to the variation of quality through constructing the dynamic recursive control model considering the human factor in a single production system. The model studied in this paper has a great advance from the point of combinating three technologies(quality control, automatic control theory, human engineering) and can also be expanded in several applications.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.37
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• pp.137-143
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• 1996

It seems to be less important to quality record than document control. But quality records provide a objectve evidence for certain product. So, the requirements of quality record is more serve than that of design document. It is obvious that quality record control promotes accumulation of know-how. The puepose of this study is to possible implementation methods through analysis of Code requirements. This paper suggests the considerations when establishing the quality records control system.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.75-81
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• 2015

This study proposes an articulated robot control system using an on/off-line robot graphic simulator with multiple networks. The proposed robot control system consists of a robot simulator using OpenGL, a robot controller based on a DSP(TMS320) motion board, and the server/client communication by multiple networks. Each client can control the real robot through a server and can compare the real robot motion with the virtual robot motion in the simulation. Also, all clients can check and analyze the robot motion simultaneously through the motion image and data of the real robot. In order to show the validity of the presented system, we present an experimental result for a 6-axis vertical articulated robot. The proposed robot control system is useful, especially, in the industrial fields using remote robot control as well as industrial production automation with many clients.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.883-890
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• 2004

In this paper, new structures of embedded internet remote control systems, which can control electo-mechanical systems, are developed. For this, remote interface system structure using embedded system are developed first, then the way of internet remote control and the PC program for the control are discussed. The developed syste in this paper can be applied to home automations such as to control entrance doors, lights, consumer electronics and other industrial applications. To show the example illustrations, in this paper, the deyeloped system has been applied to multiple motor control systems. The results show that the developed system can directly be applicable into the real industrial field.

• Journal of the Korean Operations Research and Management Science Society
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• v.21 no.2
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• pp.17-33
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• 1996

Automatic transfer defined as an integrated system with a number of workstations, interstation storage buffers, automatic device and a control system, play a major role in ass production systems. Due to high capital investment needed for an automatic transferline, greater care should be taken in its design so as to maximize the system performance. One may to control the system performance is to control buffer storage. To control the interstation work-in-process inventory, we propose dual limit switches which control the buffer storage with two parameters, R and r. Under the policy, proceding station is forced down when the inventory level in the buffer reaches R until the level falls to r. For the model developed, we analyze the system characteristics and find the optimal control parameters with a serach procedure.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.285-295
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• 1999

Developing control functions that operate and cooperate each equipment in order to achieve a goal is one of the most important problems in the installation of automated manufacturing systems. This paper discusses the development of a control system for heterarchical architecture and a simulator to verify operations of the control system. The object-oriented paradigm that has excellent reusability, portability, and extensibility is currently being used in many application fields as a software development methodology. Especially, UML(Unified Modeling Language), the third generation object-oriented modeling methodology, has advantages such as model generalization, clearness, and so on. In this research, software objects to accomodate the real time environments of automated manufacturing systems are modeled with the diagrams of UML. Based on these models, control software is developed as a format of pseudo-codes. A simulator is implemented to validate the developed control system.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.4
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• pp.869-879
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• 2001

Serial communications such as RS-232C or RS-485 have been used to control and monitor the industrial plants for a long in cooperating with a computer or microprocessor. In recent years a great deal of effort has been made to achieve these control and monitoring through Internet network. This paper proposes a microprocessor system to implement remote control and monitoring system through Internet network. The proposed system uses NE2000 compatible NIC for data link and physical layer to access Internet network The microprocessor employed in the system plays a role of interfacing NE2000 compatible NIC interpreting protocols above link layer, controlling and monitoring industrial plants simultaneously. This paper also shows MMI and experimental results which control and monitor two power plants on the computer monitor with a mouse remotely to verify the proposed.