The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform
Peilin Hong - One of the best experts on this subject based on the ideXlab platform.
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DPSAF: Forward Prediction Based Dynamic Packet Scheduling and Adjusting With Feedback for Multipath TCP in Lossy Heterogeneous Networks
IEEE Transactions on Vehicular Technology, 2018Co-Authors: Dan Ni, Qing Xu, Peilin HongAbstract:As multihomed terminals are equipped with multiple interfaces and allowed to access heterogeneous networks, transferring data simultaneously through all the available paths becomes possible and also brings many benefits. Multipath TCP (MPTCP) has been proposed to distribute an application stream over different TCP connections. However, due to the disparate latencies of different paths, the problem of existing out-of-order packets usually occurs at the receiver. Large number of these packets exhaust the limited Receiving Buffer and make the receive window be stalled, which greatly degrade the throughput. Thus, an efficient scheduling mechanism will play an important role to keep in-order delivery. However, almost all of the previous intelligent scheduling mechanisms ignored packet losses, and didn't consider window changes of the congestion control algorithm and utilize the feedback information, which cannot perform well in the lossy heterogeneous networks. In this paper we propose a new scheduling algorithm: Forward Prediction based Dynamic Packet Scheduling and Adjusting with Feedback (DPSAF). DPSAF first utilizes maximum likelihood estimation in TCP modeling to estimate the data amount sent on other paths simultaneously, which takes packet loss rate and time offset into consideration, then gets feedback information from SACK options and fixes the scheduling value. From the simulation, we can see that our mechanism obviously improves throughput and reduces cache occupancy at receiver in lossy heterogeneous networks.
Cláudio Fernando Barbosa De ,sousa - One of the best experts on this subject based on the ideXlab platform.
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Sistema para teste e paletização de uma peça para a indústria automóvel
2022Co-Authors: Cláudio Fernando Barbosa De ,sousaAbstract:Com o intuito de se conseguir fazer diversos testes a um elevado número de peças plásticas acabadas de sair de um molde de injecção, foi solicitado `a empresa WRK, Lda uma solução capaz de dar resposta aos testes exigidos e que consiga acompanhar o tempo de ciclo pretendido. Foi desenvolvida então uma solução automatizada capaz de fazer o transporte de peças de um Buffer de recepção, fazer testes de propriedades dimensionais da peça com recurso a visão artificial, fazer testes eléctricos de isolamento e continuidade e ainda a paletização da peça em caixas. Para poder fazer o transporte e paletização das peças foram utilizados dois robôs de arquitectura SCARA da marca Epson, sendo que um irá fazer o transporte de peças do Buffer de recepção para um prato rotativo, que por sua vez irá fazer a passagem das peças pelos diferentes testes. Para retirar as peças do prato irá um segundo robô SCARA pegar nestas e fazer a sua paletização em caixas de 100 peças, com camadas de 20 peças. Este robô irá ainda fazer alternância entre ferramentas, sendo uma garra para transporte das peças e uma ferramenta para poder fazer a colocação de um separador plástico entre camadas. No final, obteve-se um sistema autónomo, com um tempo de ciclo na ordem dos quarenta segundos, em que a velocidade foi um dos factores principais do uso de robôs para a manipulação dos materiais. No presente documento serão descritos os desenvolvimentos feitos ao nível de programação dos dois robôs de arquitectura SCARA que irão fazer o transporte e paletização de peças na célula. Vão ser também mostradas as decisões tomadas ao decorrer do projecto e ainda a programação da segurança da célula envolvente onde estão incorporados os robôs, com recurso a barreiras de segurança, fechos de segurança e outros equipamentos associados.In order to be able to perform multiple tests at a high number of plastic parts that arrived from an injection mold, the company WRK, Lda was asked for a solution that could atend the required tests and be able to follow up the desired cycle time. An automated solution was then developed capable of transporting parts from a Receiving Buffer, testing dimensional properties of the part using artificial vision, electrical testing for insulation and continuity, and palletizing the part into boxes. In order to transport and palletize the parts, two Epson SCARA robots were used, one of which will transport parts from the Receiving Buffer to a rotary table, which will make the parts pass through the different tests. To remove the pieces from the plate, a second SCARA robot will pick them up and palletize them into 100-piece boxes with layers of 20 pieces. This robot will also alternate between tools, using a claw to transport the parts and a tool to place a plastic separator between layers. In the end, an autonomous system with a cycle time of about forty seconds was obtained, where speed was one of the main factors for the use of robots for material handling. This document describes the programming developments of the two SCARA architecture robots that will transport and palletize parts in the cell. It will also show the decisions taken during the project and also the safety programming of the surrounding cell where the robots are incorporated, using safety barriers, safety locks and other associated equipment
Jianping Wu - One of the best experts on this subject based on the ideXlab platform.
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PAM: Precise Receive Buffer Assignment Method in Transport Protocol for Concurrent Multipath Transfer
2010 International Conference on Communications and Mobile Computing, 2010Co-Authors: Wang Yang, Hewu Li, Jianping WuAbstract:Without proper Receiving Buffer assignment, Concurrent Multipath Transfer (CMT) could result in either not being able to achieve aggregate bandwidth or being a waste of memory resources. This paper analyses Buffer requirement for CMT and find that receive Buffer requirement is linearly correlated to ratio of round trip time of different path. Based on Buffer requirement analysis, this paper proposes PAM, a precise receive Buffer size assignment method. The simulation results verified the linear correlation and show that the PAM can effectively aggregate the bandwidth of multipath while making efficient use of memory resource.
Woo J Lee - One of the best experts on this subject based on the ideXlab platform.
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countermeasures to impacts of bandwidth and Receiving Buffer on cmt schemes
Procedia Engineering, 2011Co-Authors: Lin Cui, Xin Cui, Jingji Jin, Seok J Koh, Woo J LeeAbstract:Based on the impact investigation of both bandwidth and Receiving Buffer on concurrent multi-path transmission (CMT) schemes of Stream Control Transmission Protocol (SCTP), the authors present an adaptive policy on how to effectively apply CMT- SCTP schemes under various network conditions. Moreover, an optimal fast SACK (FACK) scheme is proposed too in this paper in order to accelerate the feedback of SACKs and further find out varieties of both available bandwidth and loss rate as soon as possible. Simulation results show that the proposed scheme could improve the traffic efficiency of the CMT scheme when Receiving Buffer is bounded and network bandwidth gets smaller.
Laurence T Yang - One of the best experts on this subject based on the ideXlab platform.
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Receiving Buffer adaptation for high speed data transfer
IEEE Transactions on Computers, 2013Co-Authors: Hao Liu, Yaoxue Zhang, Yuezhi Zhou, Laurence T YangAbstract:New applications based on cloud computing, such as data synchronization for large chain departmental stores and bank transaction records, require very high-speed data transport. Although a number of high-bandwidth networks have been built, existing transport protocols or their variants over such networks cannot fully exploit the network bandwidth. Our experiments show that the fixed-size application level Buffer employed in the receiver side is a major cause of this deficiency. A Buffer that is either too small or too large impairs the transfer performance. Due to the varied natures of network conditions and of real-time packet processing (i.e., consuming) speed at the receiver, it is important to ensure that the Buffer size is dynamically adjusted according to the perceived execution situation during runtime. In this paper, we propose Rada, a dynamic Receiving Buffer adaptation scheme for high-speed data transfer. Rada employs an exponential moving average aided scheme to quantify the data arrival rate and consumption rate in the Buffer. Based on these two rates, we develop a linear aggressive increase conservative decrease scheme to adjust the Buffer size dynamically. Moreover, a weighted mean function is employed to make the adjustment adaptive to the available memory in the receiver. Theoretical analysis is provided to demonstrate the rationale and parameter bounds of Rada. The performance of Rada is also theoretically compared with potential alternatives. We implement Rada in a Linux platform and extensively evaluate its performance in a variety of scenarios. Experimental results conform to the theoretical results, and show that Rada outperforms the static Buffer scheme in terms of throughput, memory footprint, and fairness.
