scholarly journals Contention and congestion minimization in OBS networks

2017 ◽  
Author(s):  
◽  
Ndadzibaya Masimba Gomba
Keyword(s):  
Optical Networks ◽  
Network Performance ◽  
Cost Effective ◽  
Congestion Management ◽  
Fair Use ◽  
Management Approach ◽  
Core Network ◽  
Effective Manner ◽  
Successful Establishment ◽  
End To End

All-optical networks (AON) based optical burst switching (OBS) promise to be the ultimate backbone network technology solution for next generation( NG) as well as fu­ ture generation (FG)networks because of their relatively higher resources utilization, great flexibility at lower cost and potential massive bandwidth capacities both at trans­ mission and switching levels. By design, buffering is not provisioned in interior nodes. End users exchange data with one another through end-to-end light channels, called lightpaths in which wavelength continuity is maintained. In practice, their establish­ ing, in a cost effective manner remains an inescapable challenge. The routing and wave­ length assignment (RWA) problem entices successful establishment of a physical route for each lightpath connection request, assigning a wavelength to each route and at the same time ensm·ing end to end continuity, subject to the limited number of wave­ lengths. The wavelengths must be assigned such that no lightpaths can share the same wavelength simultaneously on a given fibre, or else contentions may occur. Some data bursts may be discarded whenever contention occurs among multiple bursts that arrive simultaneously at any interior node using the same wavelength and are intended for the same output port. Because of the buffer-less nature of OBS networks, conten­ tion/congestion in the core network can quickly lead to degradation in overall network performance at moderate to high traffic levels due to heavy burst loses. In this disser­ tation we propose and evaluate a congestion management approach we refer to as '"en­ hanced congestion management" which gears towards rendering and guaranteeing a consistent QoS as well as rational and fair use of available network links. Simulation results show that the scheme can effectively minimize both contention and congestion and at the same time improving both throughput and effective utilization under mod­ erate to high network traffic loads

scholarly journals A Node-Regulated Deflection Routing Framework for Contention Minimization

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Bakhe Nleya ◽  
Andrew Mutsvangwa
Keyword(s):  
Wavelength Division Multiplexing ◽  
Network Performance ◽  
Cost Effective ◽  
Core Network ◽  
Network Resources ◽  
Deflection Routing ◽  
Wavelength Division ◽  
Backbone Networks ◽  
Candidate Solution ◽  
Data Burst

Optical Burst Switching (OBS) paradigm coupled with Dense Wavelength Division Multiplexing (DWDM) has become a practical candidate solution for the next-generation optical backbone networks. In its practical deployment only the edge nodes are provisioned with buffering capabilities, whereas all interior (core) nodes remain buffer-less. In that way the implementation becomes quite simple as well as cost effective as there will be no need for optical buffers in the interior. However, the buffer-less nature of the interior nodes makes such networks prone to data burst contention occurrences that lead to a degradation in overall network performance as a result of sporadic heavy burst losses. Such drawbacks can be partly countered by appropriately dimensioning available network resources and reactively by way of deflecting excess as well as contending data bursts to available least-cost alternate paths. However, the deflected data bursts (traffic) must not cause network performance degradations in the deflection routes. Because minimizing contention occurrences is key to provisioning a consistent Quality of Service (QoS), we therefore in this paper propose and analyze a framework (scheme) that seeks to intelligently deflect traffic in the core network such that QoS degradations caused by contention occurrences are minimized. This is by way of regulated deflection routing (rDr) in which neural network agents are utilized in reinforcing the deflection route choices at core nodes. The framework primarily relies on both reactive and proactive regulated deflection routing approaches in order to prevent or resolve data burst contentions. Simulation results show that the scheme does effectively improve overall network performance when compared with existing contention resolution approaches. Notably, the scheme minimizes burst losses, end-to-end delays, frequency of contention occurrences, and burst deflections.

A cost-effective voltage security constrained congestion management approach for transmission system operation improvement

2022 ◽  
Vol 203 ◽  
pp. 107674
Author(s):  
Mahmoud Roustaei ◽  
Armin Letafat ◽  
Morteza Sheikh ◽  
Alireza chabok ◽  
Ramin Sadoughi ◽  
...  
Keyword(s):  
Cost Effective ◽  
Congestion Management ◽  
Transmission System ◽  
Management Approach ◽  
System Operation ◽  
Voltage Security ◽  
Effective Voltage

scholarly journals A Flexibility Market Platform for Electricity System Operators Using Blockchain Technology

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 539
Author(s):  
Valeri Mladenov ◽  
Vesselin Chobanov ◽  
George Calin Seritan ◽  
Radu Florin Porumb ◽  
Bogdan-Adrian Enache ◽  
...  
Keyword(s):  
Cost Effective ◽  
Congestion Management ◽  
Smart Contracts ◽  
Blockchain Technology ◽  
Electricity System ◽  
Distributed Ledger ◽  
Distributed Ledger Technology ◽  
Energy Flows ◽  
Effective Manner

The paper’s main objective is to demonstrate the trading and flexibility of services amongst TSOs, DSOs, and Prosumers in a transparent, secure, and cost-effective manner using Blockchain-based TSO-DSO flexibility marketplace (EFLEX). The aim is to look for ways to help DSOs/TSOs be more flexible and more directly engaged in managing energy flows on the network. EFLEX will streamline the needs of both TSO and DSO on the same platform. Based on the paper’s proposed services, the pilot service demonstration will be carried out in Bulgaria and Romania, and the main focus will be on congestion management, TSO-DSO Coordination, and Marketplace. The proposed objective is achieved by using Blockchain-based smart contracts and distributed ledger technology.

Strategic planning in grassland farming: Principles andapplications

1997 ◽  
pp. 191-197
Author(s):  
W.J. Parker ◽  
N.M. Shadbolt ◽  
D.I. Gray
Keyword(s):  
Strategic Planning ◽  
Performance Indicators ◽  
Cost Effective ◽  
Key Performance Indicators ◽  
Strategic Plans ◽  
Effective Manner ◽  
Farm Business ◽  
Pastoral Farming ◽  
Financial Environment

Three levels of planning can be distinguished in grassland farming: strategic, tactical and operational. The purpose of strategic planning is to achieve a sustainable long-term fit of the farm business with its physical, social and financial environment. In pastoral farming, this essentially means developing plans that maximise and best match pasture growth with animal demand, while generating sufficient income to maintain or enhance farm resources and improvements, and attain personal and financial goals. Strategic plans relate to the whole farm business and are focused on the means to achieve future needs. They should be routinely (at least annually) reviewed and monitored for effectiveness through key performance indicators (e.g., Economic Farm Surplus) that enable progress toward goals to be measured in a timely and cost-effective manner. Failure to link strategy with control is likely to result in unfulfilled plans. Keywords: management, performance

scholarly journals Novel Regeneration Approach for Creating Reusable FO-SPR Probes with NTA Surface Chemistry

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 186
Author(s):  
Jia-Huan Qu ◽  
Karen Leirs ◽  
Remei Escudero ◽  
Žiga Strmšek ◽  
Roman Jerala ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Fluorescent Protein ◽  
Cost Effective ◽  
Nitrilotriacetic Acid ◽  
Antibody Fragments ◽  
Rapid Screening ◽  
Red Fluorescent Protein ◽  
Effective Manner ◽  
Surface Regeneration ◽  
Sensitivity Specificity

To date, surface plasmon resonance (SPR) biosensors have been exploited in numerous different contexts while continuously pushing boundaries in terms of improved sensitivity, specificity, portability and reusability. The latter has attracted attention as a viable alternative to disposable biosensors, also offering prospects for rapid screening of biomolecules or biomolecular interactions. In this context here, we developed an approach to successfully regenerate a fiber-optic (FO)-SPR surface when utilizing cobalt (II)-nitrilotriacetic acid (NTA) surface chemistry. To achieve this, we tested multiple regeneration conditions that can disrupt the NTA chelate on a surface fully saturated with His6-tagged antibody fragments (scFv-33H1F7) over ten regeneration cycles. The best surface regeneration was obtained when combining 100 mM EDTA, 500 mM imidazole and 0.5% SDS at pH 8.0 for 1 min with shaking at 150 rpm followed by washing with 0.5 M NaOH for 3 min. The true versatility of the established approach was proven by regenerating the NTA surface for ten cycles with three other model system bioreceptors, different in their size and structure: His6-tagged SARS-CoV-2 spike fragment (receptor binding domain, RBD), a red fluorescent protein (RFP) and protein origami carrying 4 RFPs (Tet12SN-RRRR). Enabling the removal of His6-tagged bioreceptors from NTA surfaces in a fast and cost-effective manner can have broad applications, spanning from the development of biosensors and various biopharmaceutical analyses to the synthesis of novel biomaterials.

scholarly journals Exploring a New Adaptive Routing Based on the Dijkstra Algorithm in Optical Networks-on-Chip

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 54
Author(s):  
Yan-Li Zheng ◽  
Ting-Ting Song ◽  
Jun-Xiong Chai ◽  
Xiao-Ping Yang ◽  
Meng-Meng Yu ◽  
...  
Keyword(s):  
Power Consumption ◽  
Power Control ◽  
Optical Networks ◽  
Output Power ◽  
Network Performance ◽  
Transmission Loss ◽  
Adaptive Routing ◽  
Dijkstra Algorithm ◽  
Networks On Chip ◽  
On Chip

The photoelectric hybrid network has been proposed to achieve the ultrahigh bandwidth, lower delay, and less power consumption for chip multiprocessor (CMP) systems. However, a large number of optical elements used in optical networks-on-chip (ONoCs) generate high transmission loss which will influence network performance severely and increase power consumption. In this paper, the Dijkstra algorithm is adopted to realize adaptive routing with minimum transmission loss of link and reduce the output power of the link transmitter in mesh-based ONoCs. The numerical simulation results demonstrate that the transmission loss of a link in optimized power control based on the Dijkstra algorithm could be maximally reduced compared with traditional power control based on the dimensional routing algorithm. Additionally, it has a greater advantage in saving the average output power of optical transmitter compared to the adaptive power control in previous studies, while the network size expands. With the aid of simulation software OPNET, the network performance simulations in an optimized network revealed that the end-to-end (ETE) latency and throughput are not vastly reduced in regard to a traditional network. Hence, the optimized power control proposed in this paper can greatly reduce the power consumption of s network without having a big impact on network performance.

scholarly journals Postnatal management of children with antenatal hydronephrosis

2020 ◽  
Vol 26 (1) ◽  
Author(s):  
Mohammed S. ElSheemy
Keyword(s):  
Renal Function ◽  
Urinary Tract Obstruction ◽  
Cost Effective ◽  
Voiding Cystourethrography ◽  
Main Body ◽  
Antenatal Hydronephrosis ◽  
Postnatal Management ◽  
Effective Manner ◽  
Lower Urinary Tract Obstruction

Abstract Background Postnatal management of infants with antenatal hydronephrosis (ANH) is still one of the most controversial issues. The majority of infants with ANH are asymptomatic with only few children who develop renal insufficiency. Thus, the biggest challenge for pediatric urologists is to distinguish children who will require further investigations and possible intervention prior to the development of symptoms, complications or renal damage in a cost effective manner without exposing them to the hazards of unnecessary investigations. Main body In this review article, literature on ANH were reviewed to present the current suggestions, recommendations, guidelines and their rational for postnatal management of ANH. It is agreed that a large portion of infants with ANH will improve; thus, the protocol of management is based mainly on observation and follow-up by ultrasound to detect either resolution, stabilization or worsening of hydronephrosis. The first 2 years of life are critical for this follow-up as the final picture is mostly reached during that period. Advanced imaging using voiding cystourethrography or renal scintigraphy are required for children at risk. Then, surgical intervention is selected only for a subgroup of these infants who showed worsening of hydronephrosis or renal function. Conclusions The protocol of management is based mainly on observation and follow-up by US to detect either resolution, stabilization or worsening of hydronephrosis. Postnatal evaluation should be performed for any neonate with a history ANH at any stage during pregnancy even if it was resolved during third trimester. Exclusion of UTI should be performed by urinalysis for all cases followed by urine culture if indicated. Serum creatinine should be performed especially in patients with bilateral ANH. US is the initial standard diagnostic imaging technique. Other imaging modalities like VCUG and nuclear renal scans may be required according to the results of the US evaluation. The most important items in decision making are the presence of bilateral or unilateral hydronephrosis, presence or absence of hydroureter, presence of lower urinary tract obstruction and degree of hydronephrosis on the initial postnatal US. Then an intervention is selected only for a subgroup of these patients who showed deterioration in renal function or degree of hydronephrosis or were complicated by UTIs. All these recommendations are based on the available literature. However, management of ANH is still a controversial issue due to lack of high evidence-based recommendations. Randomised controlled studies are still needed to provide a high level evidence for different aspects of management.

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