• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.5
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• pp.218-225
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• 2001

This paper analyses the performance of network system using the CAN(Controller Area Network) protocol. Given messages are assumed to be scheduled by the DMS(Deadline Monotonic Scheduling) algorithm. The mathematical models for time-delay that can be occurred between CAN nodes are defined. The effectiveness of modeling is shown by comparing the difference of time-delay between simulations and practical experiments. We analyse the results according to the variation of factors, such as the number of nodes, the transmission speed, the message size and the number of aperiodic messages through simulation and confirm the real-time performance of lower priority messages. We also investigate the real-time performance of periodic messages when aperiodic message generates.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.219-220
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• 2009

Many surveillance cameras used in security system are controlled with RS-485 communication protocol. In this situation, if RS-485 connection can be replaced with wireless connection using sensor network technology, an installation will become ease because of no wired connection and also a deployment of cameras will become free. This paper explains about the design of wireless sensor node and the necessary implementation for an operation, which can be replacing RS-485 connection for the development of CCTV control system based on wireless sensor network. The hardware platform of sensor node was designed based on MicaZ and the software was developed based on TinyOS. To control surveillance cameras deployed on wide area, the supporting of multi-hop also was implemented. With the result of experiment deploying on real environment, it was revealed that the controller could control cameras quickly with wireless.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.167-171
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• 2004

In this Paper, We are going to propose the fire protection system with using CAN(Controller Area Network). The larger, higher and deeper buildings are, the more dangerous people are when fire happens. We are aware of the problems of prior Fire protection system. Therefore, we construct embedded system based on CAN communication that is capable of N:N communication, and build independent Fire protection system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.69-72
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• 2008

In the paper, embedded system that manage, control the status of vehicle through internet and mobile instruments are designed. The network is composed of the distributed control system using CAN communication, where communication is possible with two lines, and the bluetooth, where wireless communication is possible. We also designed the Embedded system to make up the web server only for the vehicle, made it possible to catch hold of the conditions of the vehicle and control the vehicle through internet by interfacing the destributed controller. We also made such a Web Server possible th be monitored and controlled by the mobile instruments such as PDA, mobile phones.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.3
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• pp.95-99
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• 2003

In this paper, the power system automation based on CAN communication protocol is introduced. Along with digitalization of electrical device, the various on-line services such as remote control, remote monitoring, remote parameter setting, fault data recording and remote diagnostic have been realized and become available. Therefore, it is necessary for those electrical devices to have real-time and reliable communication protocols. Author proposes DNPC(Distributed Network Protocol with CAN) which is proper to the power system SCADA (Supervisory Control And Data Acquisition) and DCS (Distributed Control System). The physical and datalink layer of DNPC protocol consists of the CAN2.0B which has the real-time characteristics and powerful error control scheme. As the transport and application layer, DNP3.0 is adopted because of its flexibility and compatible feature. Using the DNPC protocol, the power system automation is realized.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.677-680
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• 2003

In this paper, the analysis of practical end-to-end delay in worst case is performed for distributed control system considering the implementation of the system. The control system delay is composed of the delay caused by multi-task scheduling of operating system, the delay caused by network communication, and the delay caused by the asynchronous between them. Through simulation tests based on CAN(Controller Area Network), the proposed end-to-end delay in worst case is validated. Additionally, online clock synchronization algorithm is proposed here for the control system. Through another simulation test, the online algorithm is proved to have better performance than offline one in the view of network bandwidth utilization.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.2
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• pp.124-133
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• 2009

CANopen which is one of the in-vehicle network (IVN) protocols is adopted to solve the hardware dependency problem of the CAN-based application. CANopen makes different CAN devices interoperable each others. By the advantage of the device profiling concept, it can make the period of developing CAN-based application system shorten. The utilization of CANopen network must be reduced to improve the communication performance (e.g. worst-case response time). For reducing network utilization, messages need to be packed as many as possible so that message frame overhead can be decreased. In this paper, we suggested a PDO packing mechanism using object dictionary (OD) and process data object (PDO) communication service in CANopen. Through experiments, the performance of the mechanism is evaluated with SAE benchmark. As a result, network utilization is decreased about 10% compared to the result of the previous works.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.6
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• pp.614-620
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• 2006

Today the automobile has been changed from a mechanical system to an electronic control system fly the development of the electronic technology. In the automobile body, most of these electronic control devices are networked and managed fully by the CAN protocol. But, when a network system is overloaded, unexpected transmission delay for relative low priority objects occurs due to the static priority definition of the CAN protocol. To resolve this problem, this paper proposes a dynamic precedence queue mechanism that creates a queue for the low priority object and its relevant objects to be transmitted, which becomes urgent in an overloaded network system to keep the maximum allowable time delay. For the generated queue, the highest priority is assigned to transmit the queued objects within the shortest time. The mechanism is implemented in the logical link layer of CAN, which does not require any modification of the old CAN hardware. Effectiveness of the proposed mechanism is verified by the real experiments with an automobile network system.

• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.597-606
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• 2021

Due to the characteristics of the farmland in Korea, forward and reverse shift is the most used. The fatigue of farmers is caused by forward and reverse shifting with a manual transmission. Therefore, it is necessary to improve the convenience of forward and backward shifting. This study was a basic study on the development of a current control system for forward and reverse shifting of agricultural tractors using proportional control valves and a controller. A test bench was fabricated to evaluate the current control accuracy of the control system, and the stability of the controller was evaluated through CPU (central processing unit) load measurements. A controller was selected to evaluate the stability of the proportional valve controller. The stability evaluation was performed by comparing and analyzing the command current of the controller and the actual current measured. The command current was measured using a CAN (controller area network) communication device and DAQ (data acquisition). The actual current was measured with a current probe and an oscilloscope. The control system and stability evaluation was performed by measuring the CPU load on the controller during control operations. The average load factor was 12.27%, and when 5 tasks were applied, it was shown to be 70.65%. This figure was lower than the CPU limit of 74.34%, when 5 tasks were applied and was judged to be a stable system.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.123-130
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• 2010

A steering control system based on CAN(Controller Area Network) for autonomous tractor was developed to reduce duty of a central processing computer and to improve performance of steering control in terms of reduced control interval and error. The steering control system consisted of a SCU (Steering Control Unit), an EHPS system, and a potentiometer. The SCU consisted of an MCU (Micro Controller unit), an A/D converter, and a DC-DC converter, and a PID controller was used to control steering angle. The steering control system was communicated with the computer by CAN-bus. Each actuator and implement was connected to a multi-function board interfacing with the computer through a USB cable. Without CAN, control interval of the autonomous tractor was 1.5 seconds. When the CAN-based steering control system was combined with the autonomous tractor, however, control interval of the integrated system was reduced to those less than 0.05 seconds. When the autonomous tractor was operated with 1.5-s and 0.05-s control cycles at a 0.63-m/s travelling speed, the trajectories were close to straight lines for both of the control cycles. For a 1.34-m/s traveling speed, tractor trajectory was close to sine wave with a 1.5-s control cycle, but was straight line with a 0.05-s control cycle.