To solve the slow congestion detection and rate convergence problems in the existing rate control based fair data collection schemes, a new fair data collection scheme is proposed, which is named the improved scheme w...To solve the slow congestion detection and rate convergence problems in the existing rate control based fair data collection schemes, a new fair data collection scheme is proposed, which is named the improved scheme with fairness or ISWF for short. In ISWF, a quick congestion detection method, which combines the queue length with traffic changes of a node, is used to solve the slow congestion detection problem, and a new solution, which adjusts the rate of sending data of a node by monitoring the channel utilization rate, is used to solve the slow convergence problem. At the same time, the probability selection method is used in ISWF to achieve the fairness of channel bandwidth utilization. Experiment and simulation results show that ISWF can effectively reduce the reaction time in detecting congestion and shorten the rate convergence process. Compared with the existing tree-based fair data collection schemes, ISWF can achieve better fairness in data collection and reduce the transmission delay effectively, and at the same time, it can increase the average network throughput by 9.1% or more.展开更多
Li-Fi, or known as light fidelity, is a new technology that could alleviate some network congestion for the ever-increasing internet of things (IOT). The patent for Li-Fi was created by German physicist Harald Haas in...Li-Fi, or known as light fidelity, is a new technology that could alleviate some network congestion for the ever-increasing internet of things (IOT). The patent for Li-Fi was created by German physicist Harald Haas in 2011 around visible light communication. The purpose of the following research includes the capabilities of Li-Fi Technologies and how the implementation of a Li-Fi network can improve network infrastructure. A main point is to highlight the advantages that Li-Fi technology brings to the table in comparison to traditional Wi-Fi networks like the increased bandwidth frequency, faster transmission speeds, as well as not being affected by network latency due to high traffic. Benefits that Li-Fi technologies provide to network infrastructure include the use of less energy, the need for fewer components to operate, as well as the simplicity of only needing a light source to provide high-speed internet traffic. Some of our research shows the implementation of these systems and how they can provide different benefits to different types of needs of the consumer. The research gave a complete idea about hybrid indoor systems based on Li-Fi and Wi-Fi that indicates how Li-Fi technology raises the possibilities to fulfill the technological demand in the future. Also, the part explained the security concerns of Li-Fi technology and we can consider this technology secure by updating some system protocols. At present day, Li-Fi lacks the infrastructure that Wi-Fi has, which makes replacement unideal. Rather, Li-Fi can be seen as complementary to Wi-Fi and used to improve current technology.展开更多
目的观察淤血预处理对兔肝门静脉阻断模型中肠道淤血-再灌注引起的肠道损伤和肝脏损伤的影响。方法选取雄性日本大耳兔75只,体重2.5~5.0 kg,随机分为五组:假手术组(S组)、淤血-再灌注组(OC组)、预处理A组(OC5组)、预处理B组(OC10组)、...目的观察淤血预处理对兔肝门静脉阻断模型中肠道淤血-再灌注引起的肠道损伤和肝脏损伤的影响。方法选取雄性日本大耳兔75只,体重2.5~5.0 kg,随机分为五组:假手术组(S组)、淤血-再灌注组(OC组)、预处理A组(OC5组)、预处理B组(OC10组)、预处理C组(OC15组),每组15只。S组仅行剖腹手术暴露第一肝门30 min,OC组进行门静脉阻断30 min后开放门静脉。三个预处理组门静脉操作分别为OC5组夹闭5 min,开放5 min;OC10组夹闭10 min,开放10 min;OC15组夹闭15 min,开放15 min,随后阻断门静脉30 min后开放。术后2、8、24 h通过门静脉取血,检测血清中丙二醛(MDA)含量和内毒素、肿瘤坏死因子-α(TNF-α)、丙氨酸转氨酶(ALT)浓度。术后24 h血液样本采集完毕后,再次麻醉并处死以获取回肠末端肠黏膜及肝组织,显微镜下观察病理形态学结构改变。结果与S组比较,术后2、8、24 h OC组、OC5组、OC10组和OC15组血清MDA含量、内毒素、TNF-α、ALT浓度明显升高(P<0.05)。与OC组比较,术后2、8、24 h OC5组、OC10组和OC15组血清MDA含量、内毒素、TNF-α、ALT浓度明显降低(P<0.05)。与OC5组比较,术后2、8、24 h OC10组血清MDA含量、TNF-α、ALT浓度明显降低(P<0.05)。与OC5组比较,术后2、8 h OC10组血清内毒素浓度明显降低(P<0.05)。与OC10组比较,术后8 h OC15组血清MDA含量、ALT浓度明显升高(P<0.05)。与S组比较,OC组、OC5组、OC10组和OC15组肠黏膜损伤Chiu评分明显升高(P<0.05)。与OC组比较,OC5组、OC10组和OC15组黏膜损伤Chiu评分明显降低(P<0.05)。与OC5组比较,OC10组、OC15组的肠黏膜损伤Chiu评分明显降低(P<0.05)。结论淤血预处理可以减轻由于肝门静脉阻断导致的肠道淤血-再灌注损伤,减轻内毒素血症、过度炎性反应及氧自由基对肝脏的损伤。展开更多
This paper presents a high-quality very large scale integration （VLSI） global router in X-architecture, called XGRouter, that heavily relies on integer linear pro- gramming （ILP） techniques, partition strategy and...This paper presents a high-quality very large scale integration （VLSI） global router in X-architecture, called XGRouter, that heavily relies on integer linear pro- gramming （ILP） techniques, partition strategy and particle swarm optimization （PSO）. A new ILP formulation, which can achieve more uniform routing solution than other formu- lations and can be effectively solved by the proposed PSO is proposed. To effectively use the new ILP formulation, a partition strategy that decomposes a large-sized problem into some small-sized sub-problems is adopted and the routing re- gion is extended progressively from the most congested re- git）n. In the post-processing stage of XGRouter, maze rout- ing based on new routing edge cost is designed to further optimize the total wire length and mantain the congestion uniformity. To our best knowledge, XGRouter is the first work to use a concurrent algorithm to solve the global rout- ing problem in X-architecture. Experimental results show that XGRouter can produce solutions of higher quality than other global routers. And, like several state-of-the-art global touters, XGRouter has no overflow.展开更多
Transmission control protocol （TCP） is a reli- able transport layer protocol widely used in the Internet over decades. However, the performances of existing TCP conges- tion control algorithms degrade severely in mo...Transmission control protocol （TCP） is a reli- able transport layer protocol widely used in the Internet over decades. However, the performances of existing TCP conges- tion control algorithms degrade severely in modern heteroge- neous networks with random packet losses, packet reordering and congestion. In this paper, we propose a novel TCP algo- rithm named TCP-ACC to handle all three challenges men- tioned above. It integrates 1） a real-time reorder metric for calculating the probabilities of unnecessary Fast Retransmit （FRetran） and Timeouts （TO）, 2） an improved RTT estima- tion algorithm giving more weights to packets that are sent （as opposed to received） more recently, and 3） an improved congestion control mechanism based on packet loss and re- order rate measurements. Theoretical analysis demonstrates the equilibrium throughput of TCP-ACC is much higher than traditional TCP, while maintaining good fairness with regard to other TCP algorithms in ideal network conditions. Ex- tensive experimental results using both network emulators and real network show that the algorithm achieves signifi- cant throughput improvement in heterogeneous networks as compared with other state-of-the-art algorithms.展开更多
基金supported in part by the National Natural Science Foundation of China under Grants No. 61103178, No. 60803151the Research Fund for the Doctoral Program of Higher Education of China under Grant No. 20096102120045
文摘To solve the slow congestion detection and rate convergence problems in the existing rate control based fair data collection schemes, a new fair data collection scheme is proposed, which is named the improved scheme with fairness or ISWF for short. In ISWF, a quick congestion detection method, which combines the queue length with traffic changes of a node, is used to solve the slow congestion detection problem, and a new solution, which adjusts the rate of sending data of a node by monitoring the channel utilization rate, is used to solve the slow convergence problem. At the same time, the probability selection method is used in ISWF to achieve the fairness of channel bandwidth utilization. Experiment and simulation results show that ISWF can effectively reduce the reaction time in detecting congestion and shorten the rate convergence process. Compared with the existing tree-based fair data collection schemes, ISWF can achieve better fairness in data collection and reduce the transmission delay effectively, and at the same time, it can increase the average network throughput by 9.1% or more.
文摘Li-Fi, or known as light fidelity, is a new technology that could alleviate some network congestion for the ever-increasing internet of things (IOT). The patent for Li-Fi was created by German physicist Harald Haas in 2011 around visible light communication. The purpose of the following research includes the capabilities of Li-Fi Technologies and how the implementation of a Li-Fi network can improve network infrastructure. A main point is to highlight the advantages that Li-Fi technology brings to the table in comparison to traditional Wi-Fi networks like the increased bandwidth frequency, faster transmission speeds, as well as not being affected by network latency due to high traffic. Benefits that Li-Fi technologies provide to network infrastructure include the use of less energy, the need for fewer components to operate, as well as the simplicity of only needing a light source to provide high-speed internet traffic. Some of our research shows the implementation of these systems and how they can provide different benefits to different types of needs of the consumer. The research gave a complete idea about hybrid indoor systems based on Li-Fi and Wi-Fi that indicates how Li-Fi technology raises the possibilities to fulfill the technological demand in the future. Also, the part explained the security concerns of Li-Fi technology and we can consider this technology secure by updating some system protocols. At present day, Li-Fi lacks the infrastructure that Wi-Fi has, which makes replacement unideal. Rather, Li-Fi can be seen as complementary to Wi-Fi and used to improve current technology.
文摘目的观察淤血预处理对兔肝门静脉阻断模型中肠道淤血-再灌注引起的肠道损伤和肝脏损伤的影响。方法选取雄性日本大耳兔75只,体重2.5~5.0 kg,随机分为五组:假手术组(S组)、淤血-再灌注组(OC组)、预处理A组(OC5组)、预处理B组(OC10组)、预处理C组(OC15组),每组15只。S组仅行剖腹手术暴露第一肝门30 min,OC组进行门静脉阻断30 min后开放门静脉。三个预处理组门静脉操作分别为OC5组夹闭5 min,开放5 min;OC10组夹闭10 min,开放10 min;OC15组夹闭15 min,开放15 min,随后阻断门静脉30 min后开放。术后2、8、24 h通过门静脉取血,检测血清中丙二醛(MDA)含量和内毒素、肿瘤坏死因子-α(TNF-α)、丙氨酸转氨酶(ALT)浓度。术后24 h血液样本采集完毕后,再次麻醉并处死以获取回肠末端肠黏膜及肝组织,显微镜下观察病理形态学结构改变。结果与S组比较,术后2、8、24 h OC组、OC5组、OC10组和OC15组血清MDA含量、内毒素、TNF-α、ALT浓度明显升高(P<0.05)。与OC组比较,术后2、8、24 h OC5组、OC10组和OC15组血清MDA含量、内毒素、TNF-α、ALT浓度明显降低(P<0.05)。与OC5组比较,术后2、8、24 h OC10组血清MDA含量、TNF-α、ALT浓度明显降低(P<0.05)。与OC5组比较,术后2、8 h OC10组血清内毒素浓度明显降低(P<0.05)。与OC10组比较,术后8 h OC15组血清MDA含量、ALT浓度明显升高(P<0.05)。与S组比较,OC组、OC5组、OC10组和OC15组肠黏膜损伤Chiu评分明显升高(P<0.05)。与OC组比较,OC5组、OC10组和OC15组黏膜损伤Chiu评分明显降低(P<0.05)。与OC5组比较,OC10组、OC15组的肠黏膜损伤Chiu评分明显降低(P<0.05)。结论淤血预处理可以减轻由于肝门静脉阻断导致的肠道淤血-再灌注损伤,减轻内毒素血症、过度炎性反应及氧自由基对肝脏的损伤。
文摘This paper presents a high-quality very large scale integration （VLSI） global router in X-architecture, called XGRouter, that heavily relies on integer linear pro- gramming （ILP） techniques, partition strategy and particle swarm optimization （PSO）. A new ILP formulation, which can achieve more uniform routing solution than other formu- lations and can be effectively solved by the proposed PSO is proposed. To effectively use the new ILP formulation, a partition strategy that decomposes a large-sized problem into some small-sized sub-problems is adopted and the routing re- gion is extended progressively from the most congested re- git）n. In the post-processing stage of XGRouter, maze rout- ing based on new routing edge cost is designed to further optimize the total wire length and mantain the congestion uniformity. To our best knowledge, XGRouter is the first work to use a concurrent algorithm to solve the global rout- ing problem in X-architecture. Experimental results show that XGRouter can produce solutions of higher quality than other global routers. And, like several state-of-the-art global touters, XGRouter has no overflow.
基金This work was supported by the National Science Fund for Distinguished Young Scholars of China （61125102） and the State Key Program of National Natural Science Foundation of China （Grant No. 61133008）.
文摘Transmission control protocol （TCP） is a reli- able transport layer protocol widely used in the Internet over decades. However, the performances of existing TCP conges- tion control algorithms degrade severely in modern heteroge- neous networks with random packet losses, packet reordering and congestion. In this paper, we propose a novel TCP algo- rithm named TCP-ACC to handle all three challenges men- tioned above. It integrates 1） a real-time reorder metric for calculating the probabilities of unnecessary Fast Retransmit （FRetran） and Timeouts （TO）, 2） an improved RTT estima- tion algorithm giving more weights to packets that are sent （as opposed to received） more recently, and 3） an improved congestion control mechanism based on packet loss and re- order rate measurements. Theoretical analysis demonstrates the equilibrium throughput of TCP-ACC is much higher than traditional TCP, while maintaining good fairness with regard to other TCP algorithms in ideal network conditions. Ex- tensive experimental results using both network emulators and real network show that the algorithm achieves signifi- cant throughput improvement in heterogeneous networks as compared with other state-of-the-art algorithms.
