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A P2P Approach to Routing in Hierarchical MANETs

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Communications and Network 2020年第3期12卷 99-121页

作者： thomas kunz Silas Echegini Babak Esfandiari Systems and Computer Engineering Carleton University Ottawa Canada

We present an effective routing solution for the backbone of hierarchical MANETs. Our solution leverages the storage and retrieval mechanisms of a Distributed Hash Table (DHT) common to many (structured) P2P overlays. The DHT provides routing information in a decentralized fashion, while supporting different forms of node and network mobility. We split a flat network into clusters, each having a gateway who participates in a DHT overlay. These gateways interconnect the clusters in a backbone network. Two routing approaches for the backbone are explored: flooding and a new solution exploiting the storage and retrieval capabilities of a P2P overlay based on a DHT. We implement both approaches in a network simulator and thoroughly evaluate the performance of the proposed scheme using a range of static and mobile scenarios. We also compare our solution against flooding. The simulation results show that our solution, even in the presence of mobility, achieved well above 90% success rates and maintained very low and constant round trip times, unlike the flooding approach. In fact, the performance of the proposed inter-cluster routing solution, in many cases, is comparable to the performa

Forwarding vs. Network Coding: Efficient Broadcasting in Multihop Wireless Networks

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International Journal of Communications, Network and System Sciences 2011年第4期4卷 205-218页

作者： Suranjit Paul thomas kunz Li Li 不详

Broadcasting is used as a building block in many MANET (Mobile Ad hoc Network) routing protocols. In addition, broadcasting is a key primitive in ad hoc networks to support group-based applications. Efficiently supporting broadcasting in multihop wireless networks is therefore important. In this paper, we compare ef-ficient broadcasting protocols based on packet forwarding with those based on network coding. Using a number of network scenarios, we derive lower bounds for the required number of packet retransmissions at the MAC layer to support broadcast with and without applying network coding techniques. We compare these lower bounds with each other, as well as with protocols proposed for each approach. More specifically, we use SMF and PDP as sample forwarding-based broadcast protocols, and a simple XOR-based coding protocol over SMF and PDP as representative network coding solution. The results show that neither packet forwarding protocols nor network coding protocols achieve the theoretical lower bounds, in particular as the size of the network area (at constant density) increases. The comparison of the lower bounds also shows that network coding does have a potential performance advantage over packet forwarding solutions for broad-casting in multi-hop wireless networks, in particular for larger fixed density networks, justifying its inherent increased complexity.

关键词： MANETs Broadcasting Multi-hop Networks SMF PDP Network Coding

P2P Overlay Performance in Large-Scale MANETs

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International Journal of Communications, Network and System Sciences 2018年第7期11卷 147-173页

作者： thomas kunz Babak Esfandiari Silas Ngozi Frank Ockenfeld Systems and Computer Engineering Carleton University Ottawa Canada Informatik Universit&#228 t Koblenz-Landau Koblenz Germany

We explored how to deploy P2P overlays in ultimately large-scale Mobile Ad-Hoc Networks (MANETs). We therefore studied the performance of P2P overlays such as Chord, creating a number of flat and hierarchical MANET networks. The hierarchical network consists of clusters, interconnected by a backbone. The subnetworks (cluster or the whole network) ran OLSR as network-layer routing protocol. Each cluster had a gateway, interconnected through a backbone that deployed flooding. As we increased the number of clusters, we kept the number of nodes in the Chord overlay constant. Using simulations in OMNeT++, we evaluated the P2P performance. Our results show that an unmodified P2P network does not perform well even for relatively small network sizes. The performance can be improved through the use of a cross-layered P2P solution, such as OneHopOverlay4MANET. However, such cross-layered approaches require complete information about overlay nodes from the routing layer and are therefore not suitable in hierarchical MANETs. For hierarchical underlays, the performance of the P2P overlay deteriorated as we increased the number of clusters. One of the main reasons is that the backbone quickly became a performance bottleneck.

关键词： MANET Distributed Hash Tables (DHT) OLSR Chord OneHopOverlay4MANET Flat and Hierarchical Routing

Towards Optimal Planning and Scheduling in Smart Homes

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Smart Grid and Renewable Energy 2019年第7期10卷 179-202页

作者： Muhammad Raisul Alam Marc St-Hilaire thomas kunz Department of Systems and Computer Engineering Carleton University Ottawa Canada School of Information Technology Carleton University Ottawa Canada

This research addresses the planning and scheduling problem in and among the smart homes in a community microgrid. We develop a bi-linear algorithm, named ECO-Trade to generate the near-optimal schedules of the households’ loads, storage and energy sources. The algorithm also facilitates Peer-to-Peer (P2P) energy trading among the smart homes in a community microgrid. However, P2P trading potentially results in an unfair cost distribution among the participating households. To the best of our knowledge, the ECO-Trade algorithm is the first near-optimal cost optimization algorithm which considers the unfair cost distribution problem for a Demand Side Management (DSM) system coordinated with P2P energy trading. It also solves the time complexity problem of our previously proposed optimal model. Our results show that the solution time of the ECO-Trade algorithm is mostly less than a minute. It also shows that 97% of the solutions generated by the ECO-Trade algorithm are optimal solutions. Furthermore, we analyze the solutions and identify that the algorithm sometimes gets trapped at a local minimum because it alternately sets the microgrid price and quantity as constants. Finally, we describe the reasons of the cost increase by a local minimum and analyze its impact on cost optimization.

关键词： Smart Homes Community Microgrid Demand Side Management (DSM) Peer-to-Peer (P2P) Energy Trading Bi-Linear Optimization

Multimedia Streaming for Ad Hoc Wireless Mesh Networks Using Network Coding

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International Journal of Communications, Network and System Sciences 2013年第5期6卷 204-220页

作者： Basil Saeed Chung-Horng Lung thomas kunz Anand Srinivasan Department of Systems and Computer Engineering Carleton University Ottawa Canada

Over the past years, we have witnessed an explosive growth in the use of multimedia applications such as audio and video streaming with mobile and static devices. Multimedia streaming applications need new approaches to multimedia transmissions to meet the growing volume demand and quality expectations of multimedia traffic. This paper studies network coding which is a promising paradigm that has the potential to improve the performance of networks for multimedia streaming applications in terms of packet delivery ratio (PDR), latency and jitter. This paper examines several network coding protocols for ad hoc wireless mesh networks and compares their performance on multimedia streaming applications with optimized broadcast protocols, e.g., BCast, Simplified Multicast Forwarding (SMF), and Partial Dominant Pruning (PDP). The results show that the performance increases significantly with the Random Linear Network Coding (RLNC) scheme.

关键词： Wireless Broadcast Multimedia Streaming Audio Streaming Video Streaming Network Coding Random Linear Network Coding PDP SMF BCast

Network Coding and Quality of Service for Mobile <i>Ad Hoc</i>Networks

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International Journal of Communications, Network and System Sciences 2014年第10期7卷 409-422页

作者： Michael Hay Basil Saeed Chung-Horng Lung thomas kunz Anand Srinivasan Systems and Computer Engineering Carleton University Ottawa Canada EION Inc Ottawa Canada

Network Coding is a relatively new forwarding paradigm where intermediate nodes perform a store, code, and forward operation on incoming packets. Traditional forwarding approaches, which employed a store and forward operation, have not been able to approach the limit of the max-flow min-cut throughput wherein sources transmitting information over bottleneck links have to compete for access to these links. With Network Coding, multiple sources are now able to transmit packets over bottleneck links simultaneously, achieving the max-flow min-cut through-put and increasing network capacity. While the majority of the contemporary literature has focused on the performance of Network Coding from a capacity perspective, the aim of this research has taken a new direction focusing on two Quality of Service metrics, e.g., Packet Delivery Ratio (PDR) and Latency, in conjunction with Network Coding protocols in Mobile Ad Hoc Networks (MANETs). Simulations are performed on static and mobile environments to determine a Quality of Service baseline comparison between Network Coding protocols and traditional ad hoc routing protocols. The results show that the Random Linear Network Coding protocol has the lowest Latency and Dynamic Source Routing protocol has the highest PDR in the static scenarios, and show that the Random Linear Network Coding protocol has the best cumulative performance for both PDR and Latency in the mobile scenarios.

关键词： Network Coding Mobility Quality of Service Mobile Ad Hoc Networks Performance Evaluation

可调可逆式水泵水轮机组设计及抽水蓄能水电站新近成果

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可调可逆式水泵水轮机组设计及抽水蓄能水电站新近成果

北美神经内分泌肿瘤学会和核医学与分子影像学会有关177Lu-DOTATATE肽受体放射性核素治疗患者选择和合理应用共识

第十七次中国水电设备学术讨论会

作者： Jean-Bernard HOUDEL INE Daniel ROULET thomas kunz 刘杰阿尔斯通水电

本文介绍了阿尔斯通公司水泵水轮机水力设计匹配、现场试验与模型试验对比、单导叶接力器设计及其优点、针对抽水蓄能机组的运行条件下的发电电动机的设计等内容,充分体现了抽水蓄能机组的整体技术能力。

关键词：抽水蓄能水电站水泵水轮机设计发电电动机设计

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中华核医学与分子影像杂志 2020年第11期40卷 679-685页

作者：邓艳(译) 张伟(审校) thomas A.Hope Lisa Bodei Jennifer A.Chan Ghassan El-Haddad Nicholas Fidelman Pamela L.kunz Josh Mailman Yusuf Menda David C.Metz Erik S.Mittra Daniel A.Pryma Diane L.Reidy-Lagunes Simron Singh Jonathan R.Strosberg 西南医科大学附属医院儿科泸州646000 西南医科大学附属医院核医学科、核医学与分子影像四川省重点实验室泸州646000 Department of Radiology and Biomedical Imaging University of CaliforniaSan FranciscoSan FranciscoCalifornia Department of Radiology San Francisco VA Medical CenterSan FranciscoCalifornia Molecular Imaging and Therapy Service Department of RadiologyMemorial Sloan Kettering Cancer CenterNew YorkNew York Department of Medicine Dana-Farber Cancer InstituteBostonMassachusetts Department of Radiology Moffitt Cancer CenterTampaFlorida Department of Medicine Stanford University School of MedicineStanfordCalifornia NorCal CarciNET Community RiponCalifornia Department of Radiology Carver College of MedicineUniversity of IowaIowa CityIowa Division of Gastroenterology Department of MedicinePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvania Department of Diagnostic Radiology Division of Nuclear Medicine&Molecular ImagingOregon Health&Science UniversityPortlandOregon Division of Nuclear Medicine&Clinical Molecular Imaging Department of RadiologyPerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvania Department of Medicine Memorial Sloan Kettering Cancer CenterNew YorkNew York Department of Medical Oncology Odette Cancer CentreSunnybrook Health Sciences CentreTorontoOntario Department of Gastrointestinal Oncology Moffitt Cancer CenterTampaFlorida

随着177Lu-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸-D-苯丙氨酸1-酪氨酸3-苏氨酸8-奥曲肽(DOTATATE)肽受体放射性核素治疗(PRRT)的日益普及,有关患者合理选择的问题日益增多。该文回顾了有关177Lu-DOTATATE在不同原发性神经内分泌肿瘤... 详细信息

随着177Lu-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸-D-苯丙氨酸1-酪氨酸3-苏氨酸8-奥曲肽(DOTATATE)肽受体放射性核素治疗(PRRT)的日益普及,有关患者合理选择的问题日益增多。该文回顾了有关177Lu-DOTATATE在不同原发性神经内分泌肿瘤(NETs)中的应用文献,讨论了一些有争议的问题,并回顾了治疗的潜在禁忌证。此共识是由北美神经内分泌肿瘤学会(NANETS)和核医学与分子影像学会(SNMMI)共同制定的。NANETS是成立于2005年的北美多学科神经内分泌专家专业学会,目的在于通过增加研究和教育机会改善对NETs的管理。NANETS致力于多学科研究,由NETs涉及的不同专业的医师和科学家组成。SNMMI成立于1954年,旨在促进核医学科学、技术和实践应用的国际性科学专业组织,除了出版期刊、时事通讯和书籍外,还主办提高核医学从业人员能力和促进核医学科学新发展的国际会议及讲习班。

关键词： 177Lu-DOTATATE 肽受体放射性核素治疗神经内分泌肿瘤共识