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Cooperative Handoff Management for Mobile Networks
No full text對現今許多的網路服務提供者來說，因為多種無線網路技術的發展，在移動漫遊的環境中同時提供WiMAX、HSDPA與Wi-Fi等異質無線存取技術，讓使用者可以依據當時使用環境與應用程式頻寬上的需要，選擇不同種類的無線網路連接網際網路，這一直是網路服務提供者的遠景。在本篇論文中，我們提出了在無線網路漫遊的情境中，設計了讓許多網路服務提供者在合作模式中(cooperative)同時可以達到快速安全認證的漫遊方法與一個由使用者自己依據成本與頻寬的考量，自行決定的服務等級的方法。在無線服務提供者之間所形成的合作模式下，這些不同的無線網路技術將被整合為一個完整的資源。達到上述的無線漫遊網路服務目標，有四個重要的議題要在本論文探討:1)行動使用者使用IP之定址方式，在無線網路中移動的同時，也需要使用漫遊服務，而不受限於其無線網路服務提供者的服務區域；2)在缺乏互信的情況下，使用者與每個無線網路服務提供者之間、以及每個無線網路服務提供者之間必須建立彼此互相信任的關係，其中包含了計費、認證機制與無線資源分享；3)在漫遊時因為認證機制或者無線網路訊息交換所增加的漫遊時間，必須加以縮短，因為時間延遲對如網路電話或者串流服務的品質影響甚鉅；4)在有多個不同網路技術服務選擇下，在成本與頻寬的考量之下，使用者如何選擇其需要的無線網路技術。在本論文中，針對計費、認證機制我們設計了讓使用者攜帶的U-Mobile Token，此Token在合作模式下之不同無線網路服務提供者之間被認證，可以大幅縮短漫遊時因為認證、計費所造成的延遲。在此問題上我們也設計與實作【Fast and Secure Universal Roaming System】縮寫為FAS-URS (唸作Fas(t) Earth)系統，此系統證實了漫遊者在不同的無線網路服務提供者之間可以享受快速且不中斷的通訊服務。使用者的服務品質的議題上，目前無線網路服務提供者普遍使用單一定價(Flat-rate)，雖然使用者可以無限制使用網路資源，但是實際上卻無法保證網路服務品質 (Quality of Service)，我們也在異質無線服務業者的合作模式(例如WiMAX與 HSDPA)的環境下，提供使用者多個選項，使用者可以依據其所付出的成本與需要的服務等級，選擇最適合的無線網路服務。在我們的模擬中，其結果顯示，此架構同時提高了使用者的滿意度，也讓無線網路系統可以容納更多的使用者，創造更高的利益。在本論文中，我們延伸此服務模式至垂直換手服務，在垂直換手的情境中，除了可以達到無縫式換手之外，我們仍可保證其在原網路中之服務等級。Employing multiple radio access technologies such as WiMAX, HSDPA and Wi-Fi in a mobile network to provide users with more cost-effective communication services has long been a vision of many service network providers. In this thesis, we propose a security roaming solution in handover scenario and provide a novel user-decided service model in a cooperative wireless network environment and in the last, we based on user-decided service model, proposed a QoS guaranteed solution in vertical handoff scenario. When the radio resources of multiple wireless networks are collectively managed, four issues are raised in such a communication environment: a) service users would like to have IP-based roaming capability as they move rather than being constrained to a single spot or being forced to disconnect because his/her service provider does not have entire coverage of the city/region; b) the need on security and accounting management for mobile Internet; and c) the execution of AAA however would incur extra delay to handoff latency. For applications like VoIP, video streaming and TCP connections, it may disrupt the on-going communications if such latency becomes too large. d) within these versatile reless technologies, how can mobile users choose the suitable wireless network to move in. In this work, we propose an AAA-enabled roaming alliance architecture that provides fast and secure universal roaming service across multiple service domains. The associated protocols and the supporting security mechanisms are also proposed. Our design provides continuing communications service to mobile user belonging to different service operators to quickly and securely access service when roaming across multiple service domains. Mobile users only need to carry a U-Mobile Token to receive the service. The schemes proposed only incur minimal latency in security check. This is particularly important to the support of real-time mobile applications. or the novel user-decided service model which provided with multiple service options with different levels of service quality and charges. It is up to users to choose the most suitable service option (and access network) based on their personal preference and the amount of money they are willing to pay. We use a video streaming service in a WiMAX/HSDPA network as an example to illustrate the key concepts and resource management of our approach. The results of simulation show that, under the model, the service network can accommodate more users and provide higher user satisfaction than the traditional network-decided service model. It can also achieve higher resource utilization and revenues. We also extend this service model to vertical handoff service, besides providing seamless handoff, also keep the QoS service level as in the original network.Table of Contentsable of Contents Iist of Figures IIIist of Tables IV文摘要 1bstract 3 Introduction 1.1. Problem Statement and Motivation 3.2. Scope and Methodology 6.3. Contribution of This Thesis 7.4. Outline of The Thesis 8. Overview of Handoff Management and Related Works 10.1. Location Management 13.2. Horizontal handoff: Micro Mobility 14.2.1. Cellular IP 16.2.2. HAWAII 17.2.3. Hierarchical Mobile IP 18.3. Vertical Handoff 20.3.1. 3GPP Interworking Architecture 20.3.2. IEEE 802.21 22.4. Related works 24.4.1. Security Control : Mobile IP and AAA 24.4.2. QoS Control and Handoff Control : User Decided Model 28.4.3. Seamless Vertical Handoff 30. Cooperative Universal Secure Handoff Service 32.1. Problem Definition 33.2. Forming an AAA-enabled Roaming Alliance 40.2.1. Join 41.2.2. Leave 42.3. U-Mobile Token 42.3.1. Design Goal 44.3.2. Alliance Key Pair 45.3.3. Alliance Service Key 46.3.4. Content Design 47.4. Fast Roaming Authentication 49.4.1. Service Data Record(SDR) 51.4.2. Universal Roaming Service Management 52.4.3. Distribution of Alliance Private Key to Mobile Nodes 53.5. System Implementation and Performance Evaluation 56.5.1. System Implementation 56.5.2. Security Analysis 59.6. Summary of This Work 60. Cooperative User-decided Service Model 62.1. Problem Definition 63.2. Application Service: Video Streaming 65.3. Network Resource-Application View 67.3.1. WiMAX Resource Management: OFDMA Symbol Scheduling 68.3.2. Resource Management in HSDPA 70.4. The User–Decided Service Model 73.4.1. Service Charge 74.4.2. User Satisfaction 74.4.3. Scheduling with WF2Q-M 77.5. Performance Evaluation 78.5.1. Number of Users 79.5.2. User Satisfaction 81.5.3. Service Revenue 81.6. Summary of This Work 82. Vertical Handoff in WiMAX/HSDPA Interworking Network 84.1. Problem Definition 84.2. WiMAX/HSDPA Interworking Architecture 85.3. Vertical Handoff Manager 88.3.1. From HSDPA to WiMAX 89.3.2. From WiMAX to HSDPA 91.4. Performance Evaluation 92.5. Summary of This Work 98. Conclusions and Future Work 100eferences 105ppendix: Handoff Message Description 11
Performance analysis of application-level traffic shaping in a real-time multimedia conferencing system on Ethernets
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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