Distributed Failure Restoration for Asynchronous Transfer Mode (ATM) Tactical Communication Networks

Asynchronous Transfer Mode (A TM) is an attractive choice for future military communication systems because it can provide high throughput and support multi-service applications. Furthermore its use is consistent with the 'off the shelf technology policy that is currently operated by the Defence Engineering Research Agency of Great Britain. However, A TM has been developed as a civil standard and is designed to operate in network infrastructures with very low failure rates. In contrast, tactical networks are much less reliable. Indeed tactical networks operate on the premise that failures, particularly node failures, are expected. Hence, efficient, automatic failure restoration schemes are essential if an A TM based tactical network is to remain operational. The main objective of this research is the proposal and verification of one or more new restoration algorithms that meet the specific requirements of tactical networks. The aspects of ATM networks that influence restoration algorithms' implementation are discussed. In particular, the features of A TM networks such as the concept of Virtual Paths Virtual Channels and OAM (Operation And Maintenance) mechanisms that facilitate implementation of efficient restoration techniques. The unique characteristics of tactical networks and their impact on restoration are also presented. A significant part of the research was the study and evaluation of existing approaches to failure restoration in civil networks. A critical analysis of the suitability of these approaches to the tactical environment shows no one restoration algorithm fully meets the requirements of tactical networks. Consequently, two restoration algorithms for tactical A TM networks, DRA-TN (Dynamic Restoration Algorithm for Tactical Networks) and PPR-TN (Pre-planned Restoration Algorithm for Tactical Networks), are proposed and described in detail. Since the primary concern of restoration in tactical networks is the recovery of high priority connections the proposed algorithms attempt to restore high-priority connections by disrupting low-priority calls. Also, a number of additional mechanisms are proposed to reduce the use of bandwidth, which is a scarce resource in tactical networks. It is next argued that software simulation is the most appropriate method to prove the consistency of the proposed algorithms, assess their performance and test them on different network topologies as well as traffic and failure conditions. For this reason a simulation software package was designed and built specifically to model the proposed restoration algorithms. The design of the package is presented in detail and the most important implementation issues are discussed. The proposed restoration algorithms are modelled on three network topologies under various traffic loads, and their performance compared against the performance of known algorithms proposed for civil networks. It is shown that DRA-TN and PPR-TN provide better restoration of higher priority traffic. Furthermore, as the traffic load increases the relative performance of the DRA-TN and PPR-TN algorithms increases. The DRA-TN and PPR-TN algorithms are also compared and their advantages and disadvantages noted. Also, recommendations are given about the applicability of the proposed algorithms, and some practical implementation issues are discussed. The number of problems that need further study are briefly described.Defence Engineering Research Agency of Great Britai

BMSN and SpiderNet as large scale ATM switch interconnection architectures.

by Kin-Yu Cheung.Thesis (M.Phil.)--Chinese University of Hong Kong, 1997.Includes bibliographical references (leaves 64-[68]).Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Multistage Interconnection Architectures --- p.2Chapter 1.2 --- Interconnection Topologies --- p.4Chapter 1.3 --- Design of Switch Module-An Example of Multichannel Switch --- p.7Chapter 1.4 --- Organization --- p.8Chapter 1.5 --- Publication --- p.9Chapter 2 --- BMSN and SpiderNet: Two Large Scale ATM Switches --- p.13Chapter 2.1 --- Introduction --- p.13Chapter 2.2 --- Architecture --- p.14Chapter 2.2.1 --- Topology --- p.14Chapter 2.2.2 --- Switch Modules --- p.15Chapter 2.3 --- Routing --- p.17Chapter 2.3.1 --- VP/VC Routing --- p.18Chapter 2.3.2 --- VP/VC Routing Control --- p.22Chapter 2.3.3 --- Cell Routing --- p.23Chapter 2.3.4 --- Alternate Path Routing for Fault Tolerance --- p.24Chapter 2.4 --- SpiderNet --- p.25Chapter 2.5 --- Performance and Discussion --- p.26Chapter 2.5.1 --- BMSN vs SpiderNet --- p.26Chapter 2.5.2 --- Network Capacity --- p.29Chapter 2.6 --- Concluding Remarks --- p.30Chapter 3 --- Multichannel ATM Switching --- p.39Chapter 3.1 --- Introduction --- p.39Chapter 3.2 --- Switch Design --- p.40Chapter 3.3 --- Channel Allocation Algorithms --- p.41Chapter 3.3.1 --- VC-Based String Round Robin (VCB-SRR) Algorithm --- p.41Chapter 3.3.2 --- Implementation of the VCB-SRR Algorithm --- p.43Chapter 3.3.3 --- Channel Group Based Round Robin (CGB-RR) Algorithm --- p.50Chapter 3.3.4 --- Implementation of the CGB-RR Algorithm --- p.51Chapter 3.4 --- Performance and Discussion --- p.53Chapter 3.5 --- Concluding Remarks --- p.57Chapter 4 --- Conclusion --- p.62Bibliography --- p.6

Bioengineering Stents for Proactive Biocompatibility: From Biomaterials to Stents

The thesis describes methods to characterize modified biomaterial surfaces in vitro, and investigate its short term implications at the artery interface in vivo. Plasma activated coating (PAC) technology has been previously deposited on a stainless steel biomaterial (316LSS), investigated in the stent form in vivo. Initial histopathology characterizations conducted with resin-artery-stents evaluate artery-stent interface interactions in vivo. The 7 day pilot study was followed by detailed material characterization and biofunctionalization on a modified cobalt chromium metal alloy L605, for the first time herein. The outcome of this study, is to transfer optimized plasma technology to new generation cobalt chromium stents (Multi Link 8, Abbott Vascular); currently in use to treat coronary artery disease (CAD). Plasma technology is unique for its ability to not delaminate from a biomaterial, while providing surface hemocompatibility, cytocompatibility, and controlled covalent attachment of protein tropoelastin (TE), in its native conformation. The present study addressed three key questions: 1. Do PAC 316LSS stents engineered with TE improve in vivo biocompatibility at 7 days? 2. How does PAC adhere to cobalt chromium alloy L605 (novel biomaterial) to prevent delamination under stress? 3. How does PAC-L605 maintain superior hemocompatibility and promote homogenous cell culture compared to alloy L605

ANALYSIS OF DATA & COMPUTER NETWORKS IN STUDENTS' RESIDENTIAL AREA IN UNIVERSITI TEKNOLOGI PETRONAS

In Universiti Teknologi Petronas (UTP), most of the students depend on the Internet and computer network connection to gain academics information and share educational resources. Even though the Internet connections and computers networks are provided, the service always experience interruption, such as slow Internet access, viruses and worms distribution, and network abuse by irresponsible students. Since UTP organization keeps on expanding, the need for a better service in UTP increases. Several approaches were put into practice to address the problems. Research on data and computer network was performed to understand the network technology applied in UTP. A questionnaire forms were distributed among the students to obtain feedback and statistical data about UTP's network in Students' Residential Area. The studies concentrate only on Students' Residential Area as it is where most of the users reside. From the survey, it can be observed that 99% of the students access the network almost 24 hours a day. In 2005, the 2 Mbps allocated bandwidth was utilized 100% almost continuously but in 2006, the bottleneck of Internet access has reduced significantly since the bandwidth allocated have been increased to 8 Mbps. Server degradation due to irresponsible acts by users also adds burden to the main server. In general, if the proposal to ITMS (Information Technology & Media Services) Department for them to improve their Quality of Service (QoS) and established UTP Computer Emergency Response Team (UCert), most of the issues addressed in this report can be solved

Second-generation drug-eluting stents and beyond

Drug-eluting stents (DES) have become indispensable in the treatment of coronary artery disease. These coronary implants are constantly being improved to optimize safety and efficacy of treatment. Second-generation and newer-generation DES with durable polymers have shown excellent outcomes in terms of safety and efficacy both at short-term and long-term follow-up. With the improvements of stents and the overall relatively low rates of adverse events, it is becoming increasingly difficult to demonstrate a benefit of stent refinement. Therefore, it may be of interest to focus the assessment on high-risk patients or patients with complex lesions. High-risk patients can be defined according to previous studies and were shown to have increased rates of adverse clinical events. No difference in clinical outcome was observed following treatment of bifurcated versus non-bifurcated target lesions; however patients with a history of coronary bypass surgery, patients treated for at least one lesion in a small vessel (<2.50 mm), and patients with at least one severely calcified target lesion had significant higher adverse event rates than patients without these complex lesion characteristics. It may be valuable to investigate the potential benefits of stent refinements in subgroups of selected high-risk patients. In parallel with the refinement of durable polymer coated DES, stents with biodegradable coatings were developed. The absence of loss of 1-year safety and efficacy with the use of biodegradable polymer-coated DES is a prerequisite before assessing their potential longer-term benefits. The latest technical development is a bioresorbable vascular scaffold that aims at providing only a finite period of vascular support after device implantation. Based on data of our meta-analysis, the use of current-generation bioresorbable scaffolds should preferably be limited to clinical studie

The Contribution of Optical Coherence Tomography to Interventional Cardiology

__Abstract__ Since the beginning of interventional cardiology, coronary angiography has been the reference tool for assessing the severity of coronary lesions and guide stent implantation. With growing knowledge about the pathophysiology of atherothrombosis and stent failure it became of interest to visualise in vivo different processes taking place at the level of the coronary vessel wall for the purpose of improving cardiovascular outcomes. Intracoronary imaging techniques overcome the lumenographic limitations of angiography by enabling a histology-like cross-sectional view of the vessel wall and implanted devices. Although intravascular ultrasound (IVUS) has provided valuable insights into the dynamic nature of atherosclerosis and the causes of stent failure, the technology has a limited axial resolution (100-250 μm) and poor ability to differentiate between various tissue components. Intracor

10th International Conference on Business, Technology and Innovation 2021

Welcome to IC – UBT 2021 UBT Annual International Conference is the 10th international interdisciplinary peer reviewed conference which publishes works of the scientists as well as practitioners in the area where UBT is active in Education, Research and Development. The UBT aims to implement an integrated strategy to establish itself as an internationally competitive, research-intensive university, committed to the transfer of knowledge and the provision of a world-class education to the most talented students from all background. The main perspective of the conference is to connect the scientists and practitioners from different disciplines in the same place and make them be aware of the recent advancements in different research fields, and provide them with a unique forum to share their experiences. It is also the place to support the new academic staff for doing research and publish their work in international standard level. This conference consists of sub conferences in different fields like: Security Studies Sport, Health and Society Psychology Political Science Pharmaceutical and Natural Sciences Mechatronics, System Engineering and Robotics Medicine and Nursing Modern Music, Digital Production and Management Management, Business and Economics Language and Culture Law Journalism, Media and Communication Information Systems and Security Integrated Design Energy Efficiency Engineering Education and Development Dental Sciences Computer Science and Communication Engineering Civil Engineering, Infrastructure and Environment Architecture and Spatial Planning Agriculture, Food Science and Technology Art and Digital Media This conference is the major scientific event of the UBT. It is organizing annually and always in cooperation with the partner universities from the region and Europe. We have to thank all Authors, partners, sponsors and also the conference organizing team making this event a real international scientific event. Edmond Hajrizi, President of UBT UBT – Higher Education Institutio