• The KIPS Transactions:PartA
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• v.13A no.4 s.101
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• pp.317-322
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• 2006

The development of RFID system is increasing rapidly by applying to variety fields recently. Especially, RFID system is used to the focus technology of the supply chain management in distribution field of the supplier. In distribution field, We have to grasp products quickly and correctly, but this has a problem to make an inventory of products in real-time because of products transfer. In this paper, to solve this problems. We grasp the state of inventory in real-time by using EPC-IS network becoming the organizational standard of RFID network. also, We offer an authentation of product service to grasp counterfeits and stolen goods in real-time. Therefore, in this paper, We show to be able to process an authentation of product service and inventory of products in distribution field in real-time.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5S
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• pp.1666-1675
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• 2000

This paper proposes a RTWM (Real-Time Web Middleware) framework for real-time EC(Electronic Commerce) systems. RTWM system is extended the existing COS( CORBA Object Service) model added to the event monitoring, real-time scheduler, real-time event filtering for supporting real-time concept of EC systems. Especially, this paper is concentrated on providing suitable event filtering function for EC system in order to meed various user time requirements under distributed system environment. It stores time constraint requirements an interesting event information input from users into QoS repository, then processes the data through appropriate RTFA(Real-Time Filtering Agent) module when real-time events occur. From this method, users can get the filtered event result reflected their requirements about real-time filtering. It means this system provides thigh QoS to users. In addition, it results in decreasing network traffic as unnecessary event information is filtered from network.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.159-179
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• 2022

Often a network becomes complex, and multiple entities would get in charge of managing part of the whole network. An example is a utility grid. While the entire grid would go under a single utility company's responsibility, the network is often split into multiple subsections. Subsequently, each subsection would be given as the responsibility area to the corresponding sub-organization in the utility company. The issue of how to make subsystems of adequate size and minimum number of interconnections between subsystems becomes more critical, especially in real-time simulations. Because the computation capability limit of a single computation unit, regardless of whether it is a high-speed conventional CPU core or an FPGA computational engine, it comes with a maximum limit that can be completed within a given amount of execution time. The issue becomes worsened in real time simulation, in which the computation needs to be in precise synchronization with the real-world clock. When the subject of the computation allows for a longer execution time, i.e., a larger time step size, a larger portion of the network can be put on a computation unit. This translates into a larger margin of the difference between the worst and the best. In other words, even though the worst (or the largest) computational burden is orders of magnitude larger than the best (or the smallest) computational burden, all the necessary computation can still be completed within the given amount of time. However, the requirement of real-time makes the margin much smaller. In other words, the difference between the worst and the best should be as small as possible in order to ensure the even distribution of the computational load. Besides, data exchange/communication is essential in parallel computation, affecting the overall performance. However, the exchange of data takes time. Therefore, the corresponding consideration needs to be with the computational load distribution among multiple calculation units. If it turns out in a satisfactory way, such distribution will raise the possibility of completing the necessary computation in a given amount of time, which might come down in the level of microsecond order. This paper presents an effective way to split a given electrical network, according to multiple criteria, for the purpose of distributing the entire computational load into a set of even (or close to even) sized computational loads. Based on the proposed system splitting method, heavy computation burdens of large-scale electrical networks can be distributed to multiple calculation units, such as an RTDS real time simulator, achieving either more efficient usage of the calculation units, a reduction of the necessary size of the simulation time step, or both.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.178-180
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• 2007

In this paper, a real-time transmission algorithm based on IEEE 802.15.4 is proposed. The superframe of IEEE 802.15.4 is applied to the transmission method of real-time mixed data (periodic data, sporadic data, and non real-time message). The simulation results show the real-time performance of sporadic data is improved by using the proposed transmission algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.433-435
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• 2002

최근 real-time 시스템들이 많이 개발되어 상용화되고 있고, 여러 산업분야에 적용되고 있다. 한편 리눅스 운영체제의 사용이 증가하고 안정화됨에 따라, 이 시스템에 real-time 기능을 추가하기 위한 노력으로 여러 프로젝트가 진행 중에 있다. 이 가운데 시스템간에 네트웍 패킷을 송수신하고 이를 처리하는 과정에 대해 본 논문은 soft real-time을 적응하고자 한다. 기존 방식은 TOP HALF와 BOTTOM HALF로 인터럽트 처리과정을 나누어 BOTTOM HALF의 크기와 시스템 콜의 사용 빈도에 비례하여 종료시간을 예측할 수 없다. 이에 본 논문에서는 real-time 네트웍 패킷을 좀더 신속히 처리할 수 있도록 네트웍 인터럽트 처리 방안을 소개하고자 한다.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.12
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• pp.1055-1064
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• 2003

In many automated systems, such as manufacturing systems and process plants, a fieldbus is a very important component for the exchange of various and sometimes crucial information. Some of the information has a tendency to rapidly lose its value as time elapses after its creation. Such information or data is called real-time data that includes sensor values and control commands. In order to deliver these data in time, the fieldbus network should be tailored to have short delay with respect to the individual time limit of various data. Fine-tuning the network for a given traffic requires the knowledge on the relationship between the protocol parameters such as timer values and the performance measure such as network delay. This paper presents a mathematical performance model to calculate communication delays of the Profibus-FMS network when the timer value and the traffic characteristics are given.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.9
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• pp.9-17
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• 1993

There are multiple controllers (PLC. LOOP Controller ) which are operating in product line and fabrication line. In those lines, it is necessary to connect various multilple controllers with integrity and coordination. The ways to connect those devices are specified by ISO network standard. In this paper, real time network is designed and implemented for factory automation at lowest possible cost that meets the small and middle size MINI-MAP specifications. Network performance is evaluated by simulation method on data link layer implemented interfacing modules has efficiency in throughput by reducing processing time. The system designed in this paper can be also applied to the field of distributed systems for real time processing.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1032-1035
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• 1996

While Ethernet and TCP/IP are the most widely used protocol, for Real-time system, it is not applicable because it doesn't guarantee the deterministic transmission time. Furthermore, the TCP acknowledgement scheme and sliding window algorithm enforce to collide packets. Although various Collision-Free CSMA protocol was presented, it is very difficult to implement in well known OS(UNIX, WilidowsNT) because we have to modify network kernel. This paper presents another transmission protocol based on modified UDP. The colliding probability can be minimized by avoiding successive packet transmission and decreasing competition duration. The proposed algorithm can be used for the soft real-time industrial automation network.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.37 no.4
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• pp.26-36
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• 2000

This paper proposes a neural network algorithm for real-time multiprocessor scheduling problem. The proposed algorithm is developed base on Hopfield neural network for a benefit of parallel processing, in order to finish a requested task within a deadline time. To compare the performance of the proposed algorithm, we used EDA and LLA algorithm that has studied real-time multiprocessor scheduling before. The proposed algorithm is implemented hardware using VHDL.

• Current Optics and Photonics
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• v.4 no.3
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• pp.186-192
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• 2020

This paper describes a real-time monitoring system in Ethernet passive optical networks (EPON) that uses burst-mode fiber Bragg grating (FBG) optical sensors. The FBG interrogation unit in the optical line terminal (OLT) transmits the monitoring wavelength to optical network units (ONUs). The FBG sensor unit in each ONU returns a burst-mode monitoring signal to the OLT. As the system applies time division multiple access (TDMA), a uniform Bragg wavelength can be used to monitor the EPON system. The FBG interrogation unit analyzes the received burst-mode monitoring signals and outputs fault information on the ONU branches in EPON. The simulation results show the effectiveness of the proposed monitoring system based on TDMA. In addition, we compared the proposed TDMA-based monitoring system with a WDMA-based monitoring system.