scholarly journals A Buffer Management Algorithm Based on Dynamic Marking Threshold to Restrain MicroBurst in Data Center Network

Information ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 369
Author(s):  
Yan Yu ◽  
Xianliang Jiang ◽  
Guang Jin ◽  
Zihang Gao ◽  
Penghui Li
Keyword(s):  
Data Center ◽  
Completion Time ◽  
Buffer Management ◽  
Network Simulator ◽  
Design Load ◽  
Control Information ◽  
Management Algorithm ◽  
Different Types ◽  
The Face ◽  
Business Flow

The data center has become the infrastructure of most Internet services, and its network carries different types of business flow, such as query, data backup, control information, etc. At the same time, the throughput-sensitive large flows occupy a lot of bandwidth, resulting in the small flow’s longer completion time, finally affecting the performance of the applications. Recent proposals consider only dynamically adjusting the ECN threshold or reversing the ECN packet priority. This paper combines these two improvements and presents the HDCQ method for coordinating data center queuing, separating large and small flows, and scheduling in order to ensure flow completion time. It uses the ECN mechanism to design load-adaptive marking threshold update algorithms for small flows to prevent micro-bursts from occurring. At the same time, packets marked with ECN or ACK are raised in priority, prompting these packets to be fed back to the sender as soon as possible, effectively reducing the TCP control loop delay. Extensive experimental analysis on the network simulator (NS-2) shows that the HDCQ algorithm has better performance in the face of micro-burst traffic, reducing the average flow completion time by up to 24% compared with the PIAS.

Optimizing Flow Completion Time via Adaptive Buffer Management in Data Center Networks

2021 ◽  
Author(s):  
Sen Liu ◽  
Xiang Lin ◽  
Zehua Guo ◽  
Yi Wang ◽  
Mohamed Adel Serhani ◽  
...  
Keyword(s):  
Data Center ◽  
Completion Time ◽  
Buffer Management ◽  
Data Center Networks

scholarly journals An SETM Algorithm for Combating SSDF Attack in Cognitive Radio Networks

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
S. Tephillah ◽  
J. Martin Leo Manickam
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Trust Management ◽  
Cooperative Spectrum Sensing ◽  
Radio Networks ◽  
Second Phase ◽  
Common Channel ◽  
Secondary Users ◽  
Management Algorithm ◽  
Different Types

Security is a pending challenge in cooperative spectrum sensing (CSS) as it employs a common channel and a controller. Spectrum sensing data falsification (SSDF) attacks are challenging as different types of attackers use them. To address this issue, the sifting and evaluation trust management algorithm (SETM) is proposed. The necessity of computing the trust for all the secondary users (SUs) is eliminated based on the use of the first phase of the algorithm. The second phase is executed to differentiate the random attacker and the genuine SUs. This reduces the computation and overhead costs. Simulations and complexity analyses have been performed to prove the efficiency and appropriateness of the proposed algorithm for combating SSDF attacks.

Improved Jitter Buffer Management for WebRTC

2021 ◽  
Vol 17 (1) ◽  
pp. 1-20
Author(s):  
Yusuf Cinar ◽  
Peter Pocta ◽  
Desmond Chambers ◽  
Hugh Melvin
Keyword(s):  
Voice Quality ◽  
Buffer Management ◽  
Voice Over Ip ◽  
The Core ◽  
Management Algorithm ◽  
Core Concepts ◽  
Novel Strategy

This work studies the jitter buffer management algorithm for Voice over IP in WebRTC. In particular, it details the core concepts of WebRTC’s jitter buffer management. Furthermore, it investigates how jitter buffer management algorithm behaves under network conditions with packet bursts. It also proposes an approach, different from the default WebRTC algorithm, to avoid distortions that occur under such network conditions. Under packet bursts, when the packet buffer becomes full, the WebRTC jitter buffer algorithm may discard all the packets in the buffer to make room for incoming packets. The proposed approach offers a novel strategy to minimize the number of packets discarded in the presence of packet bursts. Therefore, voice quality as perceived by the user is improved. ITU-T Rec. P.863, which also confirms the improvement, is employed to objectively evaluate the listening quality.

scholarly journals Bandwidth-Aware Rescheduling Mechanism in SDN-Based Data Center Networks

Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1774
Author(s):  
Ming-Chin Chuang ◽  
Chia-Cheng Yen ◽  
Chia-Jui Hung
Keyword(s):  
Data Center ◽  
Completion Time ◽  
Network Performance ◽  
Data Locality ◽  
Task Completion ◽  
Data Center Networks ◽  
Task Completion Time ◽  
Data Packets ◽  
Network Bandwidth ◽  
Data Process

Recently, with the increase in network bandwidth, various cloud computing applications have become popular. A large number of network data packets will be generated in such a network. However, most existing network architectures cannot effectively handle big data, thereby necessitating an efficient mechanism to reduce task completion time when large amounts of data are processed in data center networks. Unfortunately, achieving the minimum task completion time in the Hadoop system is an NP-complete problem. Although many studies have proposed schemes for improving network performance, they have shortcomings that degrade their performance. For this reason, in this study, we propose a centralized solution, called the bandwidth-aware rescheduling (BARE) mechanism for software-defined network (SDN)-based data center networks. BARE improves network performance by employing a prefetching mechanism and a centralized network monitor to collect global information, sorting out the locality data process, splitting tasks, and executing a rescheduling mechanism with a scheduler to reduce task completion time. Finally, we used simulations to demonstrate our scheme’s effectiveness. Simulation results show that our scheme outperforms other existing schemes in terms of task completion time and the ratio of data locality.

scholarly journals Effect of scent on comfort of aircraft passengers

Work ◽  
2021 ◽  
Vol 68 (s1) ◽  
pp. S273-S280
Author(s):  
Xinhe Yao ◽  
Yu Song ◽  
Peter Vink
Keyword(s):  
Completion Time ◽  
Aircraft Cabin ◽  
Different Types ◽  
The Relationship ◽  
Over Time

BACKGROUND: Scents may influence the perceived comfort of an environment. There are only a few studies conducted on the relationship between scent and comfort in aircraft cabin. OBJECTIVES: The goal of this research is to explore whether relationships between scents and perceived comfort can be found for passengers in an aircraft cabin. METHODS: 276 participants joined an experiment in a Boeing 737 fuselage. The participants were divided into nine groups and each joined a session for 60 minutes with the exposure to different scents. The effect of the odor was measured by a set of questionnaires at the beginning and at the end of the session. Results of questionnaires were analyzed regarding the effects on the completion time, of the type of scents, of the intensity of the scent and on gender. RESULTS: Significant differences were found at the beginning and at the end of the experiment regarding comfort and emotion, but sometimes no relations could be established. The influence of different scents on comfort/discomfort varied and changed over time. However, in all scenarios, participant’ scores on emotion decreased. Additionally, the added scents influenced the linearity between the changes in comfort and discomfort. CONCLUSIONS: Smell could influence the perceived comfort/discomfort of aircraft passengers over time, and different types of smells have different effects on passengers. The preferences on scents are diverse, which highlights the need for personalization in aircraft cabin design.

scholarly journals Approaches to the Mechanical Properties of Threaded Studs Welded to RHS Columns

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1429
Author(s):  
Ismael García ◽  
Miguel A. Serrano ◽  
Carlos López-Colina ◽  
Fernando L. Gayarre ◽  
Jesús M. Suárez
Keyword(s):  
Mechanical Properties ◽  
Tensile Tests ◽  
Efficient Solutions ◽  
Bolted Joints ◽  
Building Structures ◽  
Static Behavior ◽  
Steel Tubes ◽  
Punch Test ◽  
Different Types ◽  
The Face

The use of Rectangular Hollow Sections (RHS) as columns in steel construction includes important advantages like higher mechanical strength and fire resistance. However, the practical demountable bolted joints between beams and columns are not easy to execute, due to impossibility of access to the inner part of the tube. The use of threaded studs welded to the face of the tube and bolted to the beam by means of angle cleats is one of the cheaper and most efficient solutions to obtain beam–column joints with a semi-rigid behavior, as is usually sought in building structures. Nevertheless, it is important to point out that the stud-diameter and the stud-class selection may affect the mechanical properties of the welded parts of the joint. In this paper, 8MnSi7 (with a commercial designation K800) and 4.8 threaded studs were welded to RHS steel tubes and mechanical properties on the weld, the Heat Affected Zones (HAZ), and the base metal were obtained in two different ways: through a correlation with the Vickers hardness and by means of the Small Punch Test (SPT). A study of the microstructure and tensile tests on the threaded studs and in the columns was also carried out. The research involved different types of stud qualities, tube wall thicknesses, and stud diameters. The work presented in this paper proved that in most cases, the welded joint between these studs and the RHS steel tubes present a reasonable static behavior that fulfils the requirements for the beam–column joints under static loading.

Intellectually Virtuous Inquirer and the Practical Value of Truth

2021 ◽  
Vol 58 (4) ◽  
pp. 54-59
Author(s):  
Sergei M. Levin ◽  
Keyword(s):  
Prima Facie ◽  
Epistemic Value ◽  
Practical Reasons ◽  
Circular Reasoning ◽  
Duncan Pritchard ◽  
Different Types ◽  
The Face

Veritism is the thesis that the truth is the fundamental epistemic good. According to Duncan Pritchard, the most pressing objections to veritism are the trivial truths objection and the trivial inquiry problem. The former states that veritism entails that trivial truths are as important as deep and important truths. The latter is a problem that a veritist must prefer trivial inquiry that generates many trivial truths to the serious inquiry with the hope but no guarantee to discover some deep and important truth. Both objections arise from the inability of veritism prima facie to properly rate the different types of truths. Pritchard's solution is to approach the truth from the perspective of the intellectually virtuous inquirer who would prefer weighty truth over trivial truth. In my commentary, I criticise the proposed solution as circular reasoning. The necessary virtue for an intellectually virtuous inquirer is that they would prefer the weighty truth over the trivial one and at the same time, the weighty truth is superior because it is the goal for intellectually virtuous inquirer. I suggest another path to substantiate veritism in the face of the two sibling objections. I argue that truth is the fundamental epistemic good as it makes the epistemic realm practically valuable more than any other epistemic good. The weighty truths are preferable to the trivial ones because the practical value of the deep and important truths is usually higher. The suggested path goes away from the attempts to prove the epistemic value of truth only within the epistemic realm, yet I argue it does not compel the intellectually virtuous inquirer to seek the truth only for the sake of practical reasons.

15. Democracies, Democratization, and Authoritarian Regimes

2020 ◽  
pp. 336-362
Author(s):  
Peter Ferdinand
Keyword(s):  
Economic Development ◽  
Recent Literature ◽  
Authoritarian Regimes ◽  
Short Term ◽  
National Crisis ◽  
Different Types ◽  
Types Of Democracy ◽  
The Face ◽  
Long Term Trends

This chapter focuses on democracies, democratization, and authoritarian regimes. It first considers the two main approaches to analysing the global rise of democracy over the last thirty years: first, long-term trends of modernization, and more specifically economic development, that create preconditions for democracy and opportunities for democratic entrepreneurs; and second, the sequences of more short-term events and actions of key actors at moments of national crisis that have precipitated a democratic transition — also known as ‘transitology’. The chapter proceeds by discussing the different types of democracy and the strategies used to measure democracy. It also reviews the more recent literature on authoritarian systems and why they persist. Finally, it examines the challenges that confront democracy in the face of authoritarian revival.

An Identifier-to-Locator Mapping Buffer Management Algorithm Based on Aimed Pushing and Pre-Fetching Method

2012 ◽  
Vol 457-458 ◽  
pp. 1317-1325
Author(s):  
Jian Wei Zhang ◽  
Bao Wei Zhang ◽  
Si Liu ◽  
Zhao Yang Li
Keyword(s):  
Buffer Management ◽  
Management Algorithm

scholarly journals Solution for the Location of Rock Cutting Elements Relative to the Rotation Center of Geohod

2019 ◽  
Vol 105 ◽  
pp. 03001 ◽  
Author(s):  
Valery Nesterov ◽  
Vladimr Aksenov ◽  
Vladimir Sadovets ◽  
Dmitry Pashkov
Keyword(s):  
Cutting Forces ◽  
Complex Shape ◽  
Rock Cutting ◽  
General Information ◽  
Technical Solution ◽  
Helical Surface ◽  
Body Form ◽  
Rotation Center ◽  
Different Types ◽  
The Face

The article presents the technical solution for the location of cutting elements relative to the rotation center of Geohod for destructing rocks with a strength up to 1 of Protodyakonov hardness. The relevancy of the research is considered. General information about Geohod is given. The features of working body of Geohod are described, in particular, the formation of a complex shape of the face and the working body, and it is also said that in the case of screw movement of working body of Geohod to the face, the points of working body form a helicoidal (helical) surface. To set the purpose and objectives of the study the geometric parameters of generatrix are justified. The parameter depending on the number of blades and on the radius of location of the blade’s cut is identified. Based on the study, the dependence of the number of blades on their location from the center to the periphery is determined. The design of blade working body of Geohod for rocks with a strength f <1 of Protodyakonov hardness is offered. Also the directions for further research have been identified, which include: the development of methods for calculating cutting forces for a technical solution for the location of cutting elements relative to the center of rotation of Geohod for destructing rocks up to 1 of Protodyakonov hardness; the application of this technique for obtaining variants of the blade working body of Geohod of different types.

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