Reconfigurable Nonlinear GRED Algorithm AL-Allaf, Ahmad F; Jabbar, A.I.A
International Journal of Computing and Digital System (Jāmiʻat al-Baḥrayn. Markaz al-Nashr al-ʻIlmī),
09/2020, Letnik:
9, Številka:
5
Journal Article
In this paper, a reconfigurable queuing scheme based on Gentle Random Early Dropping (GRED) algorithm has been proposed. Two nonlinear GRED algorithms have been suggested to study the effect of ...maximum threshold (maxth) and maximum dropping probability (maxp) in the GRED algorithm. In both algorithms, the nonlinearity degree of the two parts of the dropping probability curve of the GRED algorithm is computed to prevent the discontinuity between them. After that, a third algorithm (called Reconfigurable Nonlinear GRED "RNLGRED") is proposed. This algorithm uses the reconfigurability technique to select the best nonlinearity configuration between the first two proposed algorithms. A simulation carried out in OPNET shows that the proposed RNLGRED algorithm achieves a significant reduction in the queuing delay, jitter, and average queue size when compared with the classical GRED scheme. The reduction in queuing delay, jitter, and average queue size, for example in scenario-1, is up to 40%, 40%, and 35% respectively according to the implemented scenario. Keywords: GRED Algorithm, Queuing Schemes, Reconfigurable Queuing Algorithm
Acetaminophen (paracetamol) is one of the most used pharmaceutical drugs, due to its antipyretic and analgesic properties that turn it into a primary choice in varied pathologies and conditions. ...However, and despite its massive use, acetaminophen is not exempt of adverse effects, especially when administered in over dosage, which are related to the formation of toxic metabolites by oxidative pathways. It is thus possible to observe that toxicity caused by acetaminophen is usually mediated by reactive oxygen species and can result in multiple effects, ranging from protein denaturation to lipid peroxidation and DNA damage. The occurrence of acetaminophen has been reported in the aquatic environment, being important to address the potential exertion of toxic effects on nontarget environmentally exposed organisms. The present study intended to characterize the effects of acute acetaminophen exposure on physiological traits (antioxidant defense, oxidative damage) of two species of bivalves, namely, the edible clams
Venerupis decussata
and
Venerupis philippinarum
. Results showed a significant increase in all oxidative stress biomarkers, evidencing the bioactivation of acetaminophen into a deleterious prooxidant, triggering the onset of deleterious effects. Furthermore, strong interspecific differences were observed among responses of the two tested species, which was a major issue due to intrinsic ecological implications when one considers that both species share the same habitat.
The current problem of packets generation and transformation around the world is router congestion, which then leads to a decline in the network performance in term of queuing delay (D) and packet ...loss (PL). The existing active queue management (AQM) algorithms do not optimize the network performance because these algorithms use static techniques for detecting and reacting to congestion at the router buffer. In this paper, a weight queue active queue management (WQDAQM) based on dynamic monitoring and reacting is proposed. Queue weight and the thresholds are dynamically adjusted based on the traffic load. WQDAQM controls the queue within the router buffer by stabilizing the queue weight between two thresholds dynamically. The WQDAQM algorithm is simulated and compared with the existing active queue management algorithms. The results reveal that the proposed method demonstrates better performance in terms mean queue length, D, PL, and dropping probability, compared to gentle random early detection (GRED), dynamic GRED, and stabilized dynamic GRED in both heavy or no-congestion cases. In detail, in a heavy congestion status, the proposed algorithm overperformed dynamic GRED (DGRED) by 13.3%, GRED by 19.2%, stabilized dynamic GRED (SDGRED) by 6.7% in term of mean queue length (mql). In terms of D in a heavy congestion status, the proposed algorithm overperformed DGRED by 13.3%, GRED by 19.3%, SDGRED by 6.3%. As for PL, the proposed algorithm overperformed DGRED by 15.5%, SDGRED by 19.8%, GRED by 86.3% in term of PL.
This paper proposes the Stabilized (DGRED) method for congestion detection at the router buffer. This method aims to stabilize the average queue length between allocated minthre_shold and ...doublemaxthre_shold positions to increase the network performance. The SDGRED method is simulated and compared with Gentle Random Early Detection (GRED) and Dynamic GRED active queue management methods. This comparison is built on different important measures, such as dropping probability, throughput, average delay, packet loss, and mean queue length for packets. The evaluation aims to identify which method presents better simulation performance measurement results when non-congestion or congestion situations occur at the router buffers in congestion control. The results show that at high packet arrival probability, the proposed algorithm helps provide lesser queue length values, delayed time, and packet loss compared with current methods. Furthermore, SDGRED generates adequate throughput at high packet arrival probability.
Congestion control is one of the hot research topics that helps maintain the performance of computer networks. This paper compares three Active Queue Management (AQM) methods, namely, Adaptive Gentle ...Random Early Detection (Adaptive GRED), Random Early Dynamic Detection (REDD), and GRED Linear analytical model with respect to different performance measures. Adaptive GRED and REDD are implemented based on simulation, whereas GRED Linear is implemented as a discrete-time analytical model. Several performance measures are used to evaluate the effectiveness of the compared methods mainly mean queue length, throughput, average queueing delay, overflow packet loss probability, and packet dropping probability. The ultimate aim is to identify the method that offers the highest satisfactory performance in non-congestion or congestion scenarios. The first comparison results that are based on different packet arrival probability values show that GRED Linear provides better mean queue length; average queueing delay and packet overflow probability than Adaptive GRED and REDD methods in the presence of congestion. Further and using the same evaluation measures, Adaptive GRED offers a more satisfactory performance than REDD when heavy congestion is present. When the finite capacity of queue values varies the GRED Linear model provides the highest satisfactory performance with reference to mean queue length and average queueing delay and all the compared methods provide similar throughput performance. However, when the finite capacity value is large, the compared methods have similar results in regard to probabilities of both packet overflowing and packet dropping.
The developments in computer networks in recent days such as the internet have increased rapidly. Connections of these networks necessitate resources in order to send their data to their prospective ...destinations. Further, the connections require high speed router buffers which they route data in high speed. Congestion is one of the main issues that occur at the router buffer cause deterioration of the network performance, i.e. increasing average waiting time, decreasing throughput, etc. Gentle Random Early Detection (GRED) is one of the known congestion control algorithms proposed to detect congestion before the router buffer overflows. In fact, GRED improves the setting of the parameters for the maximum threshold position (max threshold) at the router buffer and the maximum value for the packet dropping probability (Dmax). This paper proposes an Adaptive GRED algorithm that detects congestion at router buffers in an preliminary stage, and enhances the parameters setting of the max threshold and the Dmax. During congestion, the simulation results reveal that the Adaptive GRED drops fewer packets than GRED, and it marginally offers better performance results than that of GRED.
The design thinking process involves the development of concepts and designs for products, software, buildings, machines, communication systems, and many other areas that can be used to solve ...practical and creative problems. Research in natural and laboratory contexts has identified numerous vital concepts and aspects of design thinking. Various fields have adopted design thinking methods and processes, including architecture, engineering, and business. However, the methods and techniques are primarily influenced by design thinking. Design thinking can be used in any field; it does not necessarily have to be design-oriented. Innovative products and services are also developed through a design thinking approach in business and society. The core of design thinking is user-centricity. Identifying and meeting people's needs is a critical component of the approach. Empathy depends on communication. In this paper, Ontology Web Language (OWL) is used in the protege editor to implement the discovery phase of Design Thinking. "Through the use of nomenclature and OWL properties, a variety of entities, classes, and objects are identified individually during the discovery phase.
In this article we introduce a derivation method for the Random Early Detection (RED) drop function, drawing on heuristics and control theory. This way the negative effects experienced by deploying ...the original linear RED drop probability function are improved so that link under-utilization and heavy oscillations are avoided and the function is applicable to a wide load range. As it is impossible to include all of these requirements in one approach, we show two separate approaches and combine them at the end.
The first approach aims at avoiding link under-utilization and is achieved heuristically. Therefore we provide a few examples from simulations to illustrate that the original linear RED drop function fails to avoid under-utilization and is not applicable to a wide load range. We use these examples to define conditions a proper drop function has to meet in order for under-utilization to be avoided. Bearing these conditions in mind, we propose a heuristic approach, where even a class of non-linear drop functions originates, with, apart from the usual RED parameters, one parameter free to define. Simple simulations show that such a non-linearity in the drop function should be preferred concerning the metric of under-utilization.
According to the second approach the drop function is derived analytically based on the condition to achieve system stability, i.e. to avoid heavy oscillations. Here, we use a mathematical model for the TCP window queue size behavior of a router operating with TCP and apply control theory for the derivation process. The term stability refers to the oscillation amplitude of the steady state queue size, whereas heavy oscillations indicate an unstable state. The analytically derived function is polynomial and can be approximated by using the findings of the first approach. The derived function thus avoids both under-utilization and heavy oscillations. The applicability to an arbitrary load range is included automatically in the derivation process. The impacts of parameter variations are investigated. Simulative comparisons of the derived function with ARED and with GRED (parameter variation included) with both FTP and Web traffic clearly attest to the advantage of the derivation process and to an improvement in RED performance, especially in metrics, such as link utilization, forced drops and queue size variation.
Congestion occurs in the multi-hop wireless relay routers as the packet arrival rate outpaces traffic handling capacity. Congestion introduces packet loss, queuing delay and restraint formation of ...new connections in the networks. An intelligent queue management needed in the wireless relay routers that effectively regulate the queue accumulation and avoid network congestion. In this paper, an experimental analysis of active queue and passive queue carried out under multi-hop wireless relay network to study its robustness and limitations.
Last decade seen an astronomical growth in the development of the multi-hop wireless technologies such as mobile ad-hoc network, vehicular ad-hoc network and cognitive radio network, the network ...congestion poses a serious threat in full scale deployment of wireless multi-hop technologies towards internet architecture. An active queue management (AQM) is a proactive, effective congestion control mechanism deployed at the intermediate gateway. Random Early Detection (RED) is the earliest and most widely used Active Queue Management (AQM) mechanism in backbone gateways, which in turn reduce global synchronization and bias against burst traffic. The traditional RED and its variants such GRED, AGRED, ARED, NL-RED, REM, RIO, etc. has more parameters to be tuned each time for the arrival of the packet. The tuning of more parameters leads to computation load, so it is unsuitable for low memory less devices such as laptops, handset, etc. In this paper, a micro level analysis was made on standard AQM's under multi-hop wireless environment. The results were analyzed based on the metrics such as average queue length, packet loss, queuing delay, end to end delay and throughput. This work forms a base work in designing a new queuing algorithm over heavily tailed multi-hop networks.
PDF
