Controlling the Growth of Internet Routing Tables Through Market Mechanisms

The growth of core Internet routing tables has been such that it is now viewed as an impediment to the continued expansion of the Internet. The main culprit is multi-homing that stems from sites\u27 desire for greater reliability and diversity in connectivity. These locally rational decisions have a global impact on the Internet, and there is currently no mechanism to effectively control them. A number of technical solutions are being pursued, but this paper explores the use of a market mechanism. It formulates a model that accounts for sites\u27 incentives and the impact their connectivity choices have on the size of routing tables, and introduces a pricing scheme that seeks to better reapportion the resulting costs. The model is solved for two configurations that capture different deployment realizations and stages. They demonstrate the scheme\u27s effectiveness in controlling the growth of Internet routing tables, while improving the welfare of sites and Internet Service Providers

Balancing Performance, Robustness and Flexibility in Routing Systems

Modern networks face the challenging task of handling increasingly diverse traffic that is displaying a growing intolerance to disruptions. This has given rise to many initiatives, and in this paper we focus on multiple topology routing as the primary vehicle for meeting those demands. Specifically, we seek routing solutions capable of not just accommodating different performance goals, but also preserving them in the presence of disruptions. The main challenge is computational, i.e., to identify among the enormous number of possible routing solutions the one that yields the best compromise between performance and robustness. This is where our principal contribution lies, as we expand the definition of critical links -- a key concept in improving the efficiency of routing computation -- and develop a precise methodology to efficiently converge on those solutions. Using this new methodology, we demonstrate that one can compute routing solutions that are both flexible in accommodating different performance requirements and robust in maintaining them in the presence of failures and traffic fluctuations

Balancing Performance, Robustness and Flexibility in Routing Systems

Modern networks face the daunting task of handling increasingly diverse traffic that is displaying a growing intolerance to disruptions. This has given rise to many initiatives, and in this paper we focus on multiple topology routing as the primary vehicle for meeting those demands. Specifically, we seek routing solutions capable of not just accommodating different performance goals, but also preserving them in the presence of disruptions. The main challenge is computational, i.e., to identify among the enormous number of possible routing solutions the one that yields the best compromise between performance and robustness. This is where our principal contribution lies, as we expand the definition of critical links – a key concept in improving the efficiency of routing computation – and develop a precise methodology to efficiently converge on those solutions. Using this new methodology, we demonstrate that one can compute routing solutions that are both flexible in accommodating different performance requirements and robust in maintaining them in the presence of failures and traffic fluctuations

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An Epstein-Barr virus–encoded microRNA targets PUMA to promote host cell survival

Epstein-Barr virus (EBV) is a herpesvirus associated with nasopharyngeal carcinoma (NPC), gastric carcinoma (GC), and other malignancies. EBV is the first human virus found to express microRNAs (miRNAs), the functions of which remain largely unknown. We report on the regulation of a cellular protein named p53 up-regulated modulator of apoptosis (PUMA) by an EBV miRNA known as miR-BART5, which is abundantly expressed in NPC and EBV-GC cells. Modulation of PUMA expression by miR-BART5 and anti–miR-BART5 oligonucleotide was demonstrated in EBV-positive cells. In addition, PUMA was found to be significantly underexpressed in ∼60% of human NPC tissues. Although expression of miR-BART5 rendered NPC and EBV-GC cells less sensitive to proapoptotic agents, apoptosis can be triggered by depleting miR-BART5 or inducing the expression of PUMA. Collectively, our findings suggest that EBV encodes an miRNA to facilitate the establishment of latent infection by promoting host cell survival

Speak-up culture in an intensive care unit in Hong Kong: a cross-sectional survey exploring the communication openness perceptions of Chinese doctors and nurses

Objectives Despite growing recognition of the importance of speaking up to protect patient safety in critical care, little research has been performed in this area in an intensive care unit (ICU) context. This study explored the communication openness perceptions of Chinese doctors and nurses and identified their perceptions of issues in ICU communication, their reasons for speaking up and the possible factors and strategies involved in promoting the practice of speaking up. Design A mixed-methods design with quantitative and sequential qualitative components was used. Setting and participants Eighty ICU staff members from a large public hospital in Hong Kong completed a questionnaire regarding their perceptions of communication openness. Ten clinicians whose survey responses indicated support for open communication were then interviewed about their speak-up practices. Results The participating ICU staff members had similar perceptions of their openness to communication. However, the doctors responded more positively than the nurses to many aspects of communication openness. The two groups also had different perceptions of speaking up. The interviewed ICU staff members who indicated a high level of communication openness reported that their primary reasons for speaking up were to seek and clarify information, which was achieved by asking questions. Other factors perceived to influence the motivation to speak up included seniority, relationships and familiarity with patient cases. Conclusions Creating an atmosphere of safety and equality in which team members feel confident in expressing their personal views without fear of reprisal or embarrassment is necessary to encourage ICU staff members, regardless of their position, to speak up. Because harmony and saving face is valued in Chinese culture, training nurses and doctors to speak up by focusing on human factors and values rather than simply addressing conflict management is desirable in this context.This work was supported by funding from the Hospital Authority’s Kowloon Central Cluster Research Grant (grant number: KCC/RC/G/1516-B03)

Global sagittal alignment after surgery of right thoracic idiopathic scoliosis in adolescents and adults with and without thoracic hypokyphosis

The study procedure was conducted in accordance to guidelines approved by the institutional clinical research ethics committee (CREC No. 2016.722) and the Declaration of Helsinki. Written informed consent was obtained from all subjects and their parents before participating in this study.AbstractThis study aimed to characterize global sagittal alignment in adolescent idiopathic scoliosis (AIS) with normal kyphosis (NTK, kyphosis > 10°) and with thoracic hypokyphosis (THK, kyphosis < 10°), before and after posterior spinal fusion, and compare them with asymptomatic controls. 27 AIS girls and young adults with right thoracic curves were included (seventeen with age ≤ 18 years, then age > 21). Biplanar radiographies were acquired at baseline, immediate post-operatively, 1-year and 2-year follow-up, and 3D reconstruction of the spine and pelvis was performed. NTK and THK showed different global sagittal alignment, as well as differences compared to controls. AIS with THK at baseline had higher SVA/SFD (2.0 ± 2.9 vs − 0.4 ± 1.9; P < 0.05) and OD-HA (0.2 ± 1.4° vs − 1.3 ± 1.6°; P < 0.05) than controls, indicating that THK had compensated balance with unusual forward leaning posture. Immediately post-operation, SVA/SFD remained high (1.3 ± 3.0) while OD-HA reversed (− 1.2 ± 1.7°), indicating that THK patients had found partially compensated balance. After 2-yeas, both SVA/SFD (− 1.3 ± 2.1) and OD-HA (− 1.4 ± 0.9°) were normalized. The changes in global sagittal alignment and mechanism of balance are different in AIS with or without THK. As the head plays a critical role on balance during immediate and delayed post-operation, OD-HA can be complementary parameter for assessing global balance during post-operative follow-up of AIS patients with THK.The investigation was fully supported by a grant from the General Research Funding of Hong Kong (Project no. 14206716) (W.C.W.C.), and a funding from the BiomecAM Chair Program on Musculoskeletal Modeling (with the support of Société Générale, Covea, Yves Cotrel Foundation, ParisTech Foundation and Proteor) (C.V.)

Building a sustainable internet

The Internet has become the standard infrastructure for all kinds of communications. At the same time, the emergence of cloud computing and web services has significantly strengthened requirements for the Internet to display greater robustness to disruptions and higher flexibility to support emerging applications. As hardware components are increasingly reliable and capable of handling a growing volume of Internet traffic, routing has not only become the biggest contributor to problems such as performance degradations and failures, but it also affects network flexibility and its ability to provide services. Furthermore, because of growing Internet penetration, routing is playing an ever greater role in shaping the scalability challenges that need to be met to enable the continued expansion of the Internet. The goal of the thesis is, therefore, to explore the role of routing in building a Sustainable Internet that can satisfy the future needs of communications along the dimensions of performance, flexibility, robustness, and scalability. The thesis presents a comprehensive approach to building a sustainable Internet from a routing perspective, and solves the following three challenges. The first challenge stems from the fact that IP networks need to support a wide variety of applications with diverse properties and requirements. It is therefore important to understand how routing can be designed and optimized to flexibly support diverse applications in IP networks with performance guarantees. However, flexibility without robustness to disruptions is of limited benefits, because IP networks face the daunting task of handling increasingly diverse traffic that is displaying a growing intolerance to disruptions. As a result, the second challenge is to seek routing solutions for balancing flexibility and robustness in IP networks. Furthermore, IP networks also need routing robustness for their Internet connectivity. Although it can be achieved by multi-homing, this has a global effect on the expansion of core Internet routing tables and ultimately impacts on the scalability of the Internet routing system. Thus, the third challenge is to explore solutions for controlling the growth of core Internet routing tables while balancing the needs of robustness for the Internet connectivity of IP networks

Building a sustainable internet

The Internet has become the standard infrastructure for all kinds of communications. At the same time, the emergence of cloud computing and web services has significantly strengthened requirements for the Internet to display greater robustness to disruptions and higher flexibility to support emerging applications. As hardware components are increasingly reliable and capable of handling a growing volume of Internet traffic, routing has not only become the biggest contributor to problems such as performance degradations and failures, but it also affects network flexibility and its ability to provide services. Furthermore, because of growing Internet penetration, routing is playing an ever greater role in shaping the scalability challenges that need to be met to enable the continued expansion of the Internet. The goal of the thesis is, therefore, to explore the role of routing in building a Sustainable Internet that can satisfy the future needs of communications along the dimensions of performance, flexibility, robustness, and scalability. The thesis presents a comprehensive approach to building a sustainable Internet from a routing perspective, and solves the following three challenges. The first challenge stems from the fact that IP networks need to support a wide variety of applications with diverse properties and requirements. It is therefore important to understand how routing can be designed and optimized to flexibly support diverse applications in IP networks with performance guarantees. However, flexibility without robustness to disruptions is of limited benefits, because IP networks face the daunting task of handling increasingly diverse traffic that is displaying a growing intolerance to disruptions. As a result, the second challenge is to seek routing solutions for balancing flexibility and robustness in IP networks. Furthermore, IP networks also need routing robustness for their Internet connectivity. Although it can be achieved by multi-homing, this has a global effect on the expansion of core Internet routing tables and ultimately impacts on the scalability of the Internet routing system. Thus, the third challenge is to explore solutions for controlling the growth of core Internet routing tables while balancing the needs of robustness for the Internet connectivity of IP networks