M.Sc. Jun Lei
Position:
Research Assistant
Phone:
+49 (551) 39-1 35 78
Office:
SW 0.116
Email:
Homepage
Computer Networks im April 2007
Research Projects
Publications
2007
Comparative Studies on Authentication and Key Exchange Methods for 802.11 Wireless LAN ,
Xiaoming Fu , Dieter Hogrefe , Jun Lei , Jianrong Tan, Computers & Security, Volume 26, Issue 5, Pages 401-409,
Elsevier, ISSN 0167-4048, August 2007.
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IEEE 802.11 wireless LAN has become one of the hot topics on the design and development of network access technologies. In particular, its authentication and key exchange (AKE) aspects, which form a vital building block for modern security mechanisms, deserve further investigation. In this paper we first identify the general requirements used for WLAN authentication and key exchange (AKE) methods, and then classify them into three levels (mandatory, recommended, and additional operational requirements). We present a review of issues and proposed solutions for AKE in 802.11 WLANs. Three types of existing methods for addressing AKE issues are identified, namely, the legacy, layered and access control-based AKE methods. Then, we compare these methods against the identified requirements. Based on the analysis, a multi-layer AKE framework is proposed, together with a set of design guidelines, which aims at a flexible, extensible and efficient security as well as easy deployment.
PDF [116.1 kB]
DMMP: A New Dynamic Mesh-based Overlay Multicast Protocol Framework ,
Xiaoming Fu , Dieter Hogrefe , Jun Lei , Proceedings of the 2007 IEEE Consumer Communications and Networking Conference - Workshop on Peer-to-Peer Multicasting (P2PM 2007), Las Vegas, Nevada, USA,
IEEE Communications Society, January 2007.
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Multicasting can provide an efficient way of delivering data from a sender to a group of receivers. It has received much attention over the past decade because of an increasing demand for group communication applications such as multimedia streaming. However, native IP multicast has not become widespread largely due to its technical and operational issues. To overcome these obstacles of deployment, various application layer and overlay multicast approaches have been proposed. Compared with IP multicast, they provide a new way of handling multicast without upgrading the infrastructure in a large scale. Nevertheless, they introduce a number of challenges and are still plagued with concerns on scalability, heterogeneity and dynamic performance. In this paper we propose a new protocol framework for addressing these issues, so-called the Dynamic Mesh-based Overlay Multicast Protocol or DMMP, which intends to provide an efficient and resilient multicast support by dynamically managing an overlay core comprised of end hosts. Moreover, DMMP can be used for media streaming which is contracted by a limited resource in stream supplying entities and requires good scalability and reliability. Initial analysis shows that DMMP has the potential to efficiently deliver multicast services for large groups.
PDF [311.3 kB]
2006
Dynamic Mesh-based overlay Multicast Protocol (DMMP) ,
Xiaoming Fu , Dieter Hogrefe , Jun Lei , Internet Research Task Force, Internet draft (draft-lei-samrg-dmmp-01), work in progress, Scalable Adaptive Multicast (SAM) Research Group,
October 2006.
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This document describes a Dynamic Mesh-based overlay Multicast Protocol (DMMP) to support multicast data delivery applications without relying on classic IP multicast, including multicast group management, overlay hierarchy establishment, multicast tree construction and data forwarding scheme from the source to a number of receivers. The DMMP framework builds on control plane functions which dynamically manage an overlay core and a multicast tree layer. The key idea is a number of end hosts self-organize into an overlay mesh, and dynamically maintain such a mesh. Based on the constructed mesh, some core-based clusters are built with capacity-aware trees inside. Then, a multicast tree consisting of DMMP-aware end hosts (and/or specific routers) is built on the top of the overlay core for the efficient delivery of the multicast data.
PDF [64.0 kB]
DMMP: A New Dynamic Mesh-based Overlay Multicast Protocol Framework ,
Xiaoming Fu , Dieter Hogrefe , Jun Lei , Technical Report No. IFI?TB?2006?05, Institute for Informatics, University of Goettingen, Germany,
ISSN 1611-1044, July 2006.
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Multicasting provides an efficient way of delivering data from a sender to a group of receivers. It has been gained much attention over the past decade because of an increasing demand for group communication applications such as multimedia streaming. Compared with network layer multicast solutions, recent application-layer multicast and overlay multicast approaches provide a new way of handling multicast without upgrading the infrastructure in a large scale. Meanwhile, they introduce a number of challenges and are still plagued with concerns pertaining to scalability, deployment, heterogeneity and dynamic performance. In this paper we propose a new protocol framework for relieving these issues, so-called the Dynamic Mesh-based Overlay Multicast Protocol or DMMP, which intends to provide an efficient and reliable multicast support by dynamically managing an overlay core comprised of end hosts. Although more analysis and evaluation is necessary, this paper sheds light on several identified design issues with DMMP and initially analyzes its performance.
PDF [689.2 kB]
2005
Architectural Thoughts and Requirements Considerations on Video Streaming over the Internet ,
Xiaoming Fu , Dieter Hogrefe , Ingo Juchem , Jun Lei , Technical Report No. IFI?TB?2005?06, Institute for Informatics, University of Goettingen, Germany,
ISSN 1611?1044, November 2005.
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With increasing demands of multimedia information over the Internet, video streaming has been received explosive attentions. With respect to the real-time nature of video streaming, instable bandwidth, latency, noise, packet loss, retransmission and out of order packet delivery are all problems that can affect video streaming over the Internet. However, the traditional Internet traffic is not sensitive to these problems. Based on the general video streaming architecture, we give out some considerations on design and architectural mechanisms, namely, media server, media compression, media QoS control, media distribution services, media security mechanisms and protocol stacks for video streaming. For each of these areas, we present some existing methods and implementations. Then we propose architecture via overlay multicast integrated with proxy caching to achieve efficiency, flexibility and scalability. Finally, we conclude this issue and point out the research direction.
PDF [503.1 kB]
Video Image-based Intelligent Architecture for Human Motion Capture ,
Dieter Hogrefe , Jun Lei , Jiangrong Tan, ICGST International Journal on Graphics, Vision and Image Processing (GVIP),
Volume 5, May 2005.
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The study of human motion is a fascinating subject in computer vision and has been developed quite a few years. Traditional methods to realize human motion capture mainly use equipments of machinery, electromagnetic, acoustics, optics, graphics and so on. Whereas these are some defects existed in these methods e.g. expensive equipments, the place limited by sensors and localization of sport range, and it has no consistent standards because of different purposes and requirements. Most importantly, they always need a person to execute the long and sterile work for surveillance. Sometimes only by manual operation cannot accord with desires that data should be collected without redundant or unhelpful information. In view of video characters which bring about changes and new opportunities in the human motion capturing technology, this paper presents an actual architecture to automatically capture human motion by comparing video images and extracting surveillant area. Then we provide an effective method for storage. Furthermore, the functionalities of architecture are realized in GOLF sport education example.
PDF [286.2 kB]
