• Journal of Multimedia Information System
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• v.1 no.2
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• pp.95-100
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• 2014

Variable message signs (VMS) have the different sizes and a specific type according to the city scene and it has to be displayed by different message on the display panel in real-time. And VMS manufacturers must produce the different products in order to give a customized product to each order. In addition that, they should test and check the correct operation to each VMS product using the different message frame. That is very time and workers consuming and VMS emulator with an automatic variable message generator system is necessary. Also, the automatic message generator system is needed to real-time scheduling in order to display the message on the VMS panel like real world. In this paper, we design and implement the VMS emulator embedded the automatic message frame generator system with real-time scheduling which can set several parameters easily on the windows dialog.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.570-577
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• 2016

This paper proposes the design of a novel distributed message management scheme using a message-oriented management and analysis tool (MOMAT) for naval combat system (NCS) middle-ware. If a message is not guaranteed real-time of the NCS with each node, it causes the loss of data and decreases the reliability of systems. To solve these problems, improved message management schemes are proposed. Message management schemes are considering a real-time user management scheme and a real-time traffic management scheme. The proposed schemes are simulated with a developed simulation tool, data publisher, and subscriber connected through nodes in middle-ware. The simulation results show improved results in terms of message round-trip time (RTT), End-to-End delay, and throughput.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2296-2300
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• 2005

This paper deals with the real-time message network system by a CAN (controller area network) based on the real-time distributed control scheme to integrate actuators and sensors in a humanoid robot. In order to apply the real-time distributed processing for a humanoid robot, each control unit should have the real-time efficient control method, fast sensing method, fast calculation and real-time valid data exchange method. Moreover, the data from sensors and encoders must be transmitted to the higher level of control units in maximum time limit. This paper describes the real-time message network system design and the performance of the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.856-862
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• 2002

The object-oriented(00) distributed real-time(RT) programming movement started in1990's and is growing rapidly at this turn of the century. Distributed real-time simulation is a field in its infancy but it is bounded to receive steadily growing recognition for its importance and wide applicability. The scheme is called the distributed time-triggered simulation scheme which is conceptually simple and easy to use but widely applicable. A new generation object oriented(00) RT programming scheme is called the time-triggered message triggered object(TMO)programming scheme and it is used to make specific illustrations of the issues. The TMO structuring scheme is a general-style components structuring scheme and supports design of all types of component including hard real time objects and non real time objects within one general structure.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.4
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• pp.403-410
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• 2010

The switched Ethernet has many features for real-time communications such as providing traffic isolation, large bandwidth, and full-duplex links, and so on. The switched Ethernet, however, cannot guarantee the timely delivery of a real-time message because message delay increases when collisions occurs at the output ports and message loss can even occur due to the overflow at the output buffer. Recently, many research efforts have been done to use the switched Ethernet as an industrial control network. In the industrial control network, sensors periodically sense the physical environment and transmit the sensed data to an actuator, and the periodic messages from sensors to actuators have typically real-time requirements such that those messages must be transmitted within their deadlines. This paper first suggests a feasible condition for EDF (Earliest Deadline First)-based scheduling of periodic messages on a synchronized switched Ethernet and a message scheduling algorithm which satisfies the proposed feasible condition. Pedreiras, et al. [10] suggested a feasible condition for message scheduling on the Ethernet (shared media Ethernet), but there has been no research result on the scheduling condition on the switched Ethernet until now. We compared the real-time message scheduling capacity between the Ethernet and the switched Ethernet by simulation. The simulation result shows that the message scheduling capacity of the Ethernet has almost remained constant as the number of nodes on the network increases, but, in the case of the switched Ethernet, the message scheduling capacity has increased linearly according to the number of nodes on the network.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.277-285
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• 2002

This paper proposes and analyzes an error control scheme for the transmission control based real-time communication, such as FDDI, TDMA, and wireless LAN, which delivers the message according to the round robin fashion after the off-line bandwidth allocation. Taking into account the time constraint of each message, the proposed error control scheme makes the receiver transmit the error report via asynchronous traffic while the sender resend the requested message via overallocated access time which is inevitably introduced by the bandwidth allocation procedure for hard real -time guarantee. The error control procedure does not interfere other real -time message transmissions. In addition, as each frame contains the size of the message it belongs, the receiver can recognize the end of completion of message transmission. This enables earlier error report to the receiver so that the sender can cope with more network errors. The analysis results along with simulation performed via SMPL show that the proposed scheme is able to enhance the deadline meet ratio of messages by overcoming the network errors. Using the proposed error control scheme, the hard real -time network can be built at cost lower than, but performance comparable to the expensive dual link network.

• Journal of the Korea Society of Computer and Information
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• v.21 no.5
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• pp.57-64
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• 2016

In this paper, we propose the design of railway safety common data model to provide common transformation method for collecting data from railway facility fields to Real-time railway safety monitoring and control system. This common data model is divided into five abstract sub-models according to the characteristics of data such as 'StateInfoMessage', 'ControlMessage', 'RequestMessage', 'ResponseMessage' and 'ExtendedXXXMessage'. This kind of model structure allows diverse heterogeneous data acquisitions and its common conversion method to DDS (Data Distribution Service) format to share data to the sub-systems of Real-time railway safety monitoring and control system. This paper contains the design of common data model and its DDS Topic expression for DDS communication, and presents two kinds of data transformation case studied for verification of the model design.

• The KIPS Transactions:PartC
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• v.13C no.6 s.109
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• pp.669-676
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• 2006

In this paper, we present a new framework and stream synchronization mechanism to effectively support developing real-time multimedia streaming services by using a real-time object model named TMO (Time-triggered Message-triggered Object). The purpose of the framework is twofold. Firstly, the framework helps developers to design complex distributed real-time multimedia streaming services. Secondly, it supports timely streaming facilities. In order to achieve these goals, our framework is consist of Multimedia Streaming TMO, MMStreaming TMO Support Library and TMO Support Middleware. The time-triggered spontaneous feature of the MMStream TMO and a global-time based synchronization scheme is used as a regulator against the irregular deliveries and processing of media units caused by QoS non-guaranteed systems and communication channels. In conclusion, timely service capability of our framework is expected to contributed to overall enhancement of the real-time multimedia streaming.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.684-690
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• 2006

This paper proposes a message transmission model for hard real-time communications of periodic messages on a switched Ethernet and also proposes an algorithm to schedule the messages to be transmitted within their deadlines. The proposed scheduling algorithm is a distributed one and is peformed by the source and the destination nodes without the modification of the operational features of the standard Ethernet switch. When a new periodic message needs to be transmitted, it is first checked whether it can be scheduled on both the transmission and the reception links without affecting the already-scheduled messages, and a feasible schedule is made for the new message if it is schedulable. The proposed scheduling algorithm guarantees the transmission of periodic messages within their deadline and allows flexible message transmission on a hard real-time switched Ethernet through the dynamic addition of new periodic messages during run-time.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.41-46
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• 2003

Because the quality of a radio link in real environment is generally varied with time, there is a difference between the delay in the real environment and one obtained from the analytic model where a time-varying link model is not used as a link model for a Bluetooth. This paper analyzes the transmission delay of a message in the time-varying radio link model for the Bluetooth. The time-varying radio link is modeled with a two-state Markov model. The mean transmission delay of the message is analytically obtained in terms of the arrival rate of the message, the state transition probability in the Markov model, and the packet error rate.