The real-time tasks in control systems and tits static optimal scheduling algorithm

2005 ◽  
Author(s):  
Huai Liu ◽  
Shumin Fei
Keyword(s):  
Control Systems ◽  
Real Time ◽  
Scheduling Algorithm ◽  
Optimal Scheduling ◽  
The Real

scholarly journals A New Packet Scheduling Algorithm for Real-Time Multimedia Streaming

2017 ◽  
Vol 9 (1-2) ◽  
pp. 28 ◽  
Author(s):  
Mehmet ŞİMŞEK ◽  
Nurettin Doğan ◽  
Muhammet Ali Akcayol
Keyword(s):  
Real Time ◽  
Packet Scheduling ◽  
Scheduling Algorithm ◽  
Research Question ◽  
Unintended Consequences ◽  
Just In Time ◽  
Cross Layer Design ◽  
Time Data ◽  
The Real ◽  
New Research

Delivering the real-time services over converged networks is a big challenge. Real-time services need to high Quality of Service (QoS). For this purpose, bandwidth reservation and packet prioritization techniques are used. Thus, real-time data packets can be reached to their targets with minimum delays and losses.  But, this situation creates unintended consequences for other internet services such as HTTP and FTP. In this case, establishing a balance between the real-time services and the other services is a must. In this study we introduce a new research question: how to transport real-time multimedia IP packets just in time? Just in time means that transportation of the packets neither early, nor late. For this purpose we developed a scheduling/prioritizing algorithm called just in time transport (JITT). Following a cross-layer design approach, JITT controls delay and jitter over whole communication path. We evaluated JITT on the different simulations and one experimental testbed for performance analysis. Our findings support that JITT provides stable delay and low jitter and transports the packets nearly just in time.

PERFORMANCE MODELS FOR STUDYING AND ANALYZING REAL-TIME MULTIMEDIA SYSTEMS

2006 ◽  
Vol 15 (04) ◽  
pp. 571-606
Author(s):  
SAMIR M. KORIEM
Keyword(s):  
Real Time ◽  
Service System ◽  
Scheduling Algorithm ◽  
Critical Role ◽  
Multimedia Systems ◽  
Mixed Data ◽  
Disk Scheduling ◽  
Data Types ◽  
Performance Models ◽  
The Real

As real-time systems continue to grow, performance evaluation plays a critical role in the design of these systems since the computation time, the service time, and the responsive actions must satisfy the time constraints. One of these systems is the real-time distributed multimedia-on-demand (MOD) service system. The MOD system usually fails when it misses a task deadline. The main units of the MOD system usually communicate with each other and work concurrently under timing constraints. The MOD system is designed to store, retrieve, schedule, synchronize and communicate objects comprising of mixed data types including images, text, video and audio, in real-time. In the MOD system, such data types represent the main concept of movie files. Modeling of such concurrency, communication, timing, and multimedia service (e.g., store, retrieve) is essential for evaluating the real-time MOD system. To illustrate how to model and analyze the important multimedia aspects of the MOD system, we use the Real-net (R-net) modeling technique. We choose R-net as an extension of Time Petri Net due to its ability to specify hard real-time process interaction, represent the synchronization of multimedia entities, describe concurrent multimedia activities, and illustrate the inter-process timing relationships as required for multimedia presentation. Based on modular techniques, we build three R-net performance models for describing the dynamic behavior of the MOD service system. The first model adopts the Earliest Deadline First (EDF) disk scheduling algorithm. The other models adopt the Scan-EDF algorithm. These algorithms help us to illustrate how the real-time user requests can be satisfied within the specified deadline times. Since R-nets are amenable to analysis including Markov process modeling, the interesting performance measures of the MOD service system such as the quality of service, the request response time, the disk scheduling algorithm time, and the actual retrieval time can be easily computed. In the performance analysis of the MOD models, we use our R-NET package.

scholarly journals Scheduling Algorithm for Real-Time Embedded Control Systems using Arduino Board

2017 ◽  
Vol 2 (2) ◽  
pp. 258
Author(s):  
Gokul Sidarth Thirunavukkarasu ◽  
Ragil Krishna
Keyword(s):  
Control System ◽  
Control Systems ◽  
Real Time ◽  
Error Detection ◽  
Scheduling Algorithm ◽  
Performance Ratio ◽  
Control Logic ◽  
Train Control ◽  
Train Control System ◽  
Time Scheduling

The time taken for the scheduling task in a control system to reduce the traffic within the system is one of significant field of research in modern era. There are different control systems that require time scheduling such as elevator control system, traffic control system and train control system. Currently, there are unique control logic strategies adopting scheduling algorithm that are implemented in real time systems like earliest deadline first and ant colony optimization. At the same time, the disadvantages possessed by them are the exponential dip in the performance ratio due to over loading. Despite of all the available resources there are many issues faced such as congestion in traffic networks due to non-adaptive scheduling algorithms, etc., which led to several misfortunes and danger for human life. Hence an improved algorithm that increases the efficiency of the system is required to validate the processing time and the deadlines. Our research is focused on validating a proposed idea of using Arduino microcontroller to implement the different scheduling tasks and validate the efficiency of the algorithm to optimize the results of the system. This take cares of assigning the critical paths which priorities the tasks and focuses on reducing the scheduling time. This rapidly increases the processing speed and efficiency of the algorithm. We plan to use the Arduino board which has an inbuilt error detection algorithm that helps in checking whether the time scheduling is done effectively. In the initial phase of the project we develop and fabricate the hardware design using CAD design software packages like Solid Works. This is later employed with suitable environmental interfaces like, sensors and microcontrollers that can work in an adaptable environment as per requirements to validate the scheduling algorithm. The scheduling algorithm can also be used for controlling the current flow and power storage which will contribute a lot in the power consumption aspect. Graphical data interpretation of various algorithms from the past literature is observed and few selected ones are to be implemented in the experimental set up that is built as an initial proof of concept. By analyzing the results from the simulations carried out using the Altera FPGA board with VHDL and Arduino it is clear that we obtain better results using the Arduino board. Finally, to have an extensive study on different intelligent control logics that are used in the above mentioned control systems, we use the prototyped miniature model of an elevator system and a train control system to validate the different disk scheduling approaches like First Come-First Serve (FCFS), Elevator (SCAN) and ant colonization to solve the discrete combinational optimization of the scheduling logic. Initial validation of the system focuses on the effectiveness of using the ant colonization strategies to enhances the efficiency of the scheduling algorithm and optimize it for real time application.

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