scholarly journals Controlling Data Flows in Computer Networks

Author(s):  
Ahmad AbdulQadir AlRababah

In computer networks, loss of data packets is inevitable, in particular, because of the buffer memory overflow of at least one of the nodes located on the path from the source to the receiver, including the latter. Such losses associated with overflows are hereinafter referred to as congestion of network nodes. There are many ways to prevent and eliminate overloads; these methods, in the majority, are based on the management of data flows. A special place is taken by the maintenance of packages, taking into account their priorities. The article considers a number of original technical solutions to improve the quality of control and reduce the required amount of buffer memory of network nodes. The ideas of these solutions are quite simple for their implementation in the development of appropriate software and hardware for telecommunication devices.

Author(s):  
A.I. Mikov ◽  
A.A. Mikov

We consider mobile computer networks whose stationary movements are forced to change at some points in time by external control actions or random disturbances. External influence can be aimed at the transition of the network to another stationary movement, but during the transition period there is a danger of decreasing the reliability of the network, the quality of its functioning, and even the threat of operability. One of the reasons for this is the rapid change in the topological (graph) characteristics of the network — the loss of connectivity of the dynamic graph of the network, the change in the set of available data transmission routes between nodes. The paper describes the results of statistical modeling of the characteristics of dynamic graphs for perturbed motion, and also presents algorithms for managing dynamic graphs during the transition process, which reduce the negative effects on the network from external influences. Using methods of predictive modeling, the quality of control algorithms is evaluated.


Author(s):  
Fahmi Yunistyawan ◽  
Yunistyawan J Berchmans ◽  
Gembong Baskoro

This study implements the auto start control system on an electric motor 3 phase C4Feeding pump when the discharge pressure is low-low (4.3 kg /cm²). The C4 feeding pumpmotor was initially manually operated from the local control station, this was very ineffectiveand inefficient because it still relied on the field operator to operate the pump motor and whenthe plant was in normal operating it is very risk if the field operator late to operate motor then itwill impact to quality of the product, and if the delay time to operate motor is too long then planthave to shut down, therefore improvement is needed in the C4 feeding pump motor controlsystem. In this paper, various types of 3-phase motor control are explained which allow it to beapplied to the C4 feeding pump motor that are on-off, inverter, and variable speed drive andefficient selection of the three systems control of the motor. Software and hardware used in thisthesis work are DCS CENTUM VP Yokogawa.


Author(s):  
Igor' Polyuschenkov

The materials on the development of asynchronous electric drive with scalar control are given. The technical solutions associated with the design of software and hardware parts of the microprocessor control system are described. When developed, tools of model-based programming technique are used.


1993 ◽  
Vol 28 (11-12) ◽  
pp. 257-261
Author(s):  
M. Truett Garrett ◽  
Zaki Ahmad ◽  
Shelly Young

The recent requirements by U.S.E.P.A. for dechlorination and biomonitoring have increased the importance of automatic control of effluent chlorination in wastewater treatment plants. Difficulties with the Ziegler-Nichols controller tuning procedure were reported at the Kyoto Workshop, 1990. Problems are caused by the noise of incomplete mixing, a long time constant, and the disturbances of changing flow and chlorine demand. The Astrom-Hagglund relay feedback procedure provides acceptable control while data is logged to determine the controller constants. Experiences in using the procedure in existing facilities (not redesigning the mixing point) and the quality of control are presented.


Author(s):  
D. V. Shelkovoy ◽  
A. A. Chernikov

The testing results of required channel resource mathematical estimating models for the for serving the proposed multimedia load in packet-switched communication networks are presented in the article. The assessment of the attainable level of quality of service at the level of data packet transportation was carried out by means of simulation modeling of the functioning of a switching node of a communication network. The developed modeling algorithm differs from the existing ones by taking into account the introduced delay for processing each data stream packet arriving at the switching node, depending on the size of the reserved buffer and the channel resource for its maintenance. A joint examination of the probability of packet loss and the introduced delay in the processing of data packets in the border router allows a comprehensive assessment of the quality of service «end to end», which in turn allows you to get more accurate values of the effective data transmitted rate by aggregating flows at the entrance to the transport network.


2021 ◽  
Vol 10 (2) ◽  
pp. 30
Author(s):  
Radwan S. Abujassar ◽  
Husam Yaseen ◽  
Ahmad Samed Al-Adwan

Nowadays, networks use many different paths to exchange data. However, our research will construct a reliable path in the networks among a huge number of nodes for use in tele-surgery using medical applications such as healthcare tracking applications, including tele-surgery which lead to optimizing medical quality of service (m-QoS) during the COVID-19 situation. Many people could not travel due to the current issues, for fear of spreading the covid-19 virus. Therefore, our paper will provide a very trusted and reliable method of communication between a doctor and his patient so that the latter can do his operation even from a far distance. The communication between the doctor and his/her patient will be monitored by our proposed algorithm to make sure that the data will be received without delay. We test how we can invest buffer space that can be used efficiently to reduce delays between source and destination, avoiding loss of high-priority data packets. The results are presented in three stages. First, we show how to obtain the greatest possible reduction in rate variability when the surgeon begins an operation using live streaming. Second, the proposed algorithm reduces congestion on the determined path used for the online surgery. Third, we have evaluated the affection of optimal smoothing algorithm on the network parameters such as peak-to-mean ratio and delay to optimize m-QoS. We propose a new Smart-Rout Control algorithm (s-RCA) for creating a virtual smart path between source and destination to transfer the required data traffic between them, considering the number of hops and link delay. This provides a reliable connection that can be used in healthcare surgery to guarantee that all instructions are received without any delay, to be executed instantly. This idea can improve m-QoS in distance surgery, with trusted paths. The new s-RCA can be adapted with an existing routing protocol to track the primary path and monitor emergency packets received in node buffers, for direct forwarding via the demand path, with extended features.


Author(s):  
R. Düll ◽  
A. Kulagin ◽  
W. Lee ◽  
Yu. Ozhigov ◽  
H. Miao ◽  
...  

Author(s):  
YA.L. LIBERMAN ◽  
◽  
L.N. GORBUNOVA ◽  
Keyword(s):  

2018 ◽  
Vol 22 (03) ◽  
pp. 1850024 ◽  
Author(s):  
HÉDIA FOURATI ◽  
RIHAB BEN ATTITALAH

This paper studies the entrepreneurial optimism and debt decisions for business start-up. By analysing a sample of 160 business start-up and by using the panel data estimation, we study entrepreneurs’ optimism and its impact on debt decision of business start-up. The measure of entrepreneurial optimism is based on the entrepreneur earnings forecasts initiated by Lin et al. (2005). Meanwhile, the nature of entrepreneurial experience (serial and portfolio entrepreneur) has an effect on entrepreneurial optimism and leads to more or less optimistic entrepreneur. The results reveal that optimistic entrepreneur prefers equity in funding the financial deficit. Serial entrepreneurs tend to use more debt funding. In the dynamic model, the entrepreneur acquiring business concurrently adjusts slowly to debt ratio. Nevertheless, the sequential entrepreneurial experience leads to more optimism and so on more debt use. Given the governance role played by banks, the high adjustment cost for start-up is a consequence of the efficiency of the quality of control exercised by banks that in spite of entrepreneurial optimism, the entrepreneur does not convince the financiers to be so confident on the prospect of the business.


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