• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.801-805
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• 1992

Due to the inherent complexity in the CIM operation, achieving the triple, meeting duedates, maximizing machine utilization, and maximizing system throughput simultaneously is practically impossible. Targeting the small-to-medium size industries of Korea, we propose an exrert system that 'provides a good and practical solution to the CIM operation problems. Heavy consideration has given to the real-time and dynamic nature of CIM in the development process of the system. The system is under testing stage at KU-FMS, model CIM plant.

• 대한산업공학회지
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• 제35권4호
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• pp.266-279
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• 2009

This paper focuses on the problem of scheduling wafer lots with limited waiting times between pairs of consecutive operations in a semiconductor wafer fabrication facility. For the problem of minimizing total tardiness of orders, we develop a priority rule based scheduling method in which a scheduling decision for an operation is made based on the states of workstations for the operation and its successor or predecessor operation. To evaluate performance of the suggested scheduling method, we perform simulation experiments using real factory data as well as randomly generated data sets. Results of the simulation experiments show that the suggested method performs better than a method suggested in other research and the one that has been used in practice.

• 대한전자공학회논문지SD
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• 제48권10호
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• pp.67-71
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• 2011

디지털 도어락, 디지털 카메라, 비디오 감시 시스템 등에서 사용되는 기존의 얼굴 검출 시스템은 비교적 낮은 해상도의 영상 처리를 사용하고 있으며 이를 위해서 소프트웨어 기반의 구현을 하고 있다. 하지만 이 경우에는 높은 해상도를 위한 얼굴 검출이 어려울 뿐만 아니라 수행해야할 영산 처리 양이 많기 때문에 실시간으로 얼굴을 검출하는데 어려움이 있다. 실시간 임베디드 시스템에서 HD(High Definition) 영상을 위한 효과적인 얼굴 검출을 위해서는 하드웨어적인 접근이 필요하다. 이에 본 논문에서는 얼굴 검출을 위해 사용되는 전처리 과정 중에 하나이며 처리시간이 많이 소요되는 국부 이진 패턴(LBP, Local Binary Pattern) 연산을 하드웨어 구조를 제시하고 설계했다. 그리고 제시한 하드웨어 구조를 FPGA(Field Programmable Gate Array) 칩을 통해서 구현 및 검증을 통해 고해상도 HD급 영상에서 효율적인 얼굴 검출이 가능 한 것을 확인했다.

• 한국정보과학회논문지:데이타베이스
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• 제29권6호
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• pp.464-476
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• 2002

모든 데이타를 주기억장치에 상주시키는 주기억장치 데이타베이스 시스템은 고성능 실시간 트랜잭션 처리에 적합하다. 주기억장치 데이타베이스 시스템에서 트랜잭션이 데이타베이스에 접근하는 시간이 매우 짧기 때문에 동시성 제어를 위해 이단계 로킹 기법을 사용할 경우, 로크 충돌이 일어날 확률이 적은 반면에, 데이타 객체를 접근할 때마다 수행해야 하는 로킹 연산의 부하는 트랜잭션 수행시간에 비해 상대적으로 큰 비중을 차지하게 된다. 본 논문에서는 로킹 연산의 부하를 최소화하면서 트랜잭션의 우선 순위를 반영한 실시간 정적 로킹 기법을 설계하고, 이를 주기억장치 실시간 데이타베이스 시스템인 Mr.RT에서 구현하였다. 또한 이단계 로킹 기법을 기반으로 하는 기존의 실시간 동시성 제어 기법들(2PL-PI, 2PL-HP)과의 성능 비교를 통하여 실시간 정적 로킹 기법이 보다 좋은 성능을 보임을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.674-679
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• 1987

Process failures can occur at any time during operation, so a continuous effort of fault detection, diagsis, and correction is required. Expert system paridigm has been regarded as a promising approach to real time process supervisory control especially to fault diagnosis. The most important aspects of fault diagnostic expert systems(FDES) are the problem-solving inference strategy and knowledge organizations. The necessity of FDES, the nature of diagnostic knowledge, the representation of knowledge, and the inference mechanism of FDES, et al. are described, which are announced by previous researchers. And the existing FDES are categorized and critically reviewed in this work.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2164-2168
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• 2003

Real time control system such as in factory automation fields, defense field, aerospace, railway industries, financial trading and so forth, includes multiple computers on multiple nodes, and share data to process various actions and functions. This is similar to multitasking in a multiprocessor computer system. The task processing efficiency of such system is proportionally increased by process speed of each process computer. And also it is greatly influenced by communication latencies of each node. To provide proper operation of such real time system, a network that can guarantee deterministic exchange of certain amount of data within a limited time is required. Such network is called as a real time network. As for modern distributed control system, the timeliness of data exchange gives important factor for the dynamics of entire control system. In a real time network system, exchanged data are determined by off-line design process to provide the timeliness of data. In other word, designer of network makes up a network data table that describes the specification of data exchanged between control equipments. And by this off-line design result, the network data are exchanged by predetermined schedule. First, this paper explains international standard real time network TCN (Train Communication Network) applied to the KHST (Korean High Speed Train) project. And then it explains the computer program developed for design tool of network data table of TCN.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.491-494
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• 2002

The real-time industrial network often referred to as fieldbus, is an important element for building automated manufacturing systems. Thus, in order to satisfy the real-time requirements of field devices such as sensors, actuators, and controllers. numerous standard organizations and vendors have developed various fieldbus protocols such as Profibus, WorldFIP and Foundation Fieldbus. However, the application of fieldbus has been limited due to the high cost of hardware and the difficulty in interfacing with multi-vendor products. In order to solve these problems, the computer network technology, especially Ethernet (IEEE 802.3), is being adopted lo the industrial environment. The crucial technical obstacle for Ethernet is that its non-deterministic behavior makes it inadequate for industrial applications where real-time data such as control command and alarm signal hale to be delivered within a certain time limit. Recently, the development of switched Ethernet shows a very promising prospect for industrial application due to the elimination of uncertainties in the network operation resulting in much improved performance. This paper focuses on the application of the switched Ethernet for industrial comm unications.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1727-1731
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• 2003

In this paper we proposed backward fuzzy Petri-net to diagnoses faults in power systems by using the time sequence information of protection system. As the complexity of power systems increases, especially in the case of multiple faults or incorrect operation of protective devices, fault diagnosis requires new and systematic methods to the reasoning process, which improves both its accuracy and its efficiency. The fuzzy Petri-net models of protection system are composed of the operating process of protective devices and the fault diagnosis process. Fault diagnosis model, which makes use of the nature of fuzzy Petri-net, is developed to overcome the drawbacks of methods that depend on operator knowledge. The proposed method can reduce processing time and increase accuracy when compared with the traditional methods. And also this method covers online processing of real-time data from SCADA (Supervisory Control and Data Acquisition)

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1139_1141
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• 2009

Distributed Generation (DG) is predicted to play a important role in electric power system in the near future. insertion of DG system into existing distribution network has great impact on real-time system operation and planning. It is widely accepted that micro turbine generation (MTG) systems are currently attracting lot of attention to meet customers need in the distributed power generation market In order to investigate the performance of MT generation systems, their efficient modeling is required. This paper presents the modeling and simulation of a MT generation system suitable for grid-connected operation. The system comprises of a permanent magnet synchronous generator driven by a MT. A brief description of the overall system is given, and mathematical models for the MT and permanent magnet synchronous generator are presented. Also, the use of power electronics in conditioning the power output of the generating system is demonstrated. Simulation studies with MATLAB/Simulink have been carried out in grid-connected operation mode of a DG system. The control strategies for grid connected operation mode of DG system is also presented.

• 한국시뮬레이션학회논문지
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• 제12권3호
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• pp.83-94
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• 2003

For 24 hours-7 days service on distributed systems, a great deal of efforts are investigated on high availability for seamless operation. In this paper, we propose a dynamic reconfiguration framework of distributed systems, called "hot-swapping" framework. This framework allows us to upgrade and exchange a number of modules of a distributed system without stopping running service as well as the system itself. In order to hide the state of service operation, the framework employes the "proxy" design pattern. Our framework provides two types of proxies: a static proxy and a dynamic proxy, Static proxies can achieve fast execution time, but they need to be changed whenever any minor change exists in the related swappable module. Meanwhile, dynamic proxies takes longer execution time, but do not need to be changed under minor changes of swappable modules. We compare performances of static and dynamic proxies and also apply the framework to a real situation with security management modules. management modules.