An intelligent service-based network architecture for wearable robots

We are developing a novel robot concept called the wearable robot. Wearable robots are mobile information devices capable of supporting remote communication and intelligent interaction between networked entities. In this paper, we explore the possible functions of such a robotic network and will present a distributed network architecture based on service components. In order to support the interaction and communication between the components in the wearable robot system, we have developed an intelligent network architecture. This service-based architecture involves three major mechanisms. The first mechanism involves the use of a task coordinator service such that the execution of the services can be managed using a priority queue. The second mechanism enables the system to automatically push the required service proxy to the client intelligently based on certain system-related conditions. In the third mechanism, we allow the system to automatically deliver services based on contextual information. Using a fuzzy-logic-based decision making system, the matching service can determine whether the service should be automatically delivered utilizing the information provided by the service, client, lookup service, and context sensors. An application scenario has been implemented to demonstrate the feasibility of this distributed service-based robot architecture. The architecture is implemented as extensions to the Jini network model.     

A PKI approach for deploying modern secure distributed e-learning and m-learning environments

While public key cryptography is continuously evolving and its installed base is growing significantly, recent research works examine its potential use in e-learning or m-learning environments. Public key infrastructure (PKI) and attribute certificates (ACs) can provide the appropriate framework to effectively support authentication and authorization services, offering mutual trust to both learners and service providers. Considering PKI requirements for online distance learning networks, this paper discusses the potential application of ACs in a proposed trust model. Typical e-learning trust interactions between e-learners and providers are presented, demonstrating that robust security mechanisms and effective trust control can be obtained and implemented. The application of ACs to support m-learning is also presented and evaluated through an experimental test-bed setup, using the general packet radio service network. The results showed that AC issuing is attainable in service times while simultaneously can deliver flexible and scalable solutions to both learners and e-learning providers.     

ServBGP: BGP-inspired autonomic service routing for multi-provider collaborative architectures in the cloud

In this paper we propose the design and implementation of ServBGP, a service routing protocol for managing service collaboration among cloud providers in cloud computing. ServBGP is based on the policy-driven design of the well-known BGP Internet routing protocol to support the different service interaction models currently employed in the cloud particularly the monolithic, composite, and broker-based service models. The main contribution of this work lies in devising a system that autonomously manages the different aspects of service interaction and collaboration among service providers from service discovery and advertisement to service consumption and revocation. The ServBGP routing decision engine is designed to operate by (1) processing cost-bidding service advertisement and revocation messages from the different cloud providers and (2) extracting objective and trustworthy feedback which is maintained by certified network entities and which consists of a set of reputation scores related to quality of service, security, and pricing. The BGP-inspired design choice allows the proposed system to “stand upon the shoulders of giants” by relying on a time-tested protocol that currently supports scalable inter-domain routing services among over 120,000 IPv4 prefixes in the Internet. Moreover, reusing the decision logic of the standard BGP protocol aids in reducing the development and operational costs, hence shortening the time to market, and utilizing a large set of BGP extensions, particularly, in the security domain, that have been incorporated into BGP since its inception in 1989. These qualities are of a chief importance in the cloud community today to ensure the efficient and secure service collaboration among cloud providers and to support the evolution, scalability, and economic feasibility of the overall cloud computing infrastructure. A proof of concept implementation of the ServBGP design is realized on the NetKit network emulation and virtualization platform using the standard BGPv4 protocol. Moreover, the devised ServBGP design is developed from the ground up and deployed in a real cloud computing environment using Amazon EC2, Microsoft Azure, and Google App Engine cloud platforms.     

Scalable public-key tracing and revoking

Traitor tracing schemes constitute a useful tool against piracy in the context of digital content distribution. They are encryption schemes that can be employed by content providers that wish to deliver content to an exclusive set of users. Each user holds a decryption key that is fingerprinted and bound to his identity. When a pirate decoder is discovered, it is possible to trace the identities of the users that contributed to its construction. In most settings, both the user population and the set of content providers are dynamic, thus scalable user management and scalable provider management are crucial. Previous work on public-key traitor tracing did not address the dynamic scenario thoroughly: no efficient scalable public-key traitor tracing scheme has been proposed, in which the populations of providers and users can change dynamically over time without incurring substantial penalty in terms of system performance and management complexity. To address these issues, we introduce a formal model for Scalable Public-Key Traitor Tracing, and present the first construction of such a scheme. Our model mandates for deterministic traitor tracing and unlimited number of efficient provider and user management operations. We present a formal adversarial model for our system and we prove our construction secure, against both adversaries that attempt to cheat the provider and user management mechanism, and adversaries that attempt to cheat the traitor tracing mechanism.Received: 28 August 2003, Accepted: 13 October 2004, Published online: 13 January 2005     

Dynamic pricing of call rates: Bayesian approach

In this paper, we present different cases and their possible solutions in the telecommunications market by incorporating dynamically changing call rates over the channel depending upon the network congestion. Since dynamic pricing of call rates is beneficial from both the perspectives of subscribers and service providers, our solution can significantly help to adapt this pricing mechanism in real market scenario. In order to deploy this scheme, we have incorporated the competing network provider's strategy into the mechanism of deciding dynamic price. Establishment of Nash equilibrium with the competing network provider has stabilized our pricing mechanism.     

A cost-efficient method for streaming stored content in a guaranteed QoS Internet

Quality-of-service techniques allow network providers to differentiate the services they offer to their customers. This differentiation makes it possible to consider charging new quality transport services based on network resource usage. In a content streaming framework, consumers pay for content and network access. Similarly, content providers pay to reserve transport service resources to deliver high-quality content. Therefore, content providers need new cost-efficient methods that optimize network resource reservations. Our paper proposes a new method that ensures data availability on the client side while optimizing network resource reservation when servers deliver stored content with semi-elastic unicast flows. The method uses network resource reservation to guarantee the delivery rate when stored data is below a minimum threshold in the client memory. When occupancy reaches a maximum threshold, the transmission changes to the classic best-effort service, which is not charged based on usage but at a flat rate. The proper design of these thresholds optimizes transmission cost. We validate our analytical method using the ns-2 simulator. We also present a new approach for improving this method when the best-effort delivery rate from the server to the client presents higher variability. Finally, we analyse the case of several homogeneous clients that simultaneously require resource reservation from the server. To avoid resource reservation rejection in the server, bandwidth must be suitably allocated among the clients. To evaluate this more complex case, we also perform some simulations and implement the associated prototype to validate the simulations. The qualitative simulation results reveal optimum working areas in which usage-cost reduction efficiency of the method is significant and extra signalling is minimum.     

新型多层联合组通信模型的设计与性能分析

针对流媒体业务需要网络提供大规模组通信支持的应用需求,将网络层组通信模型和应用层组通信模型,按域内和域间的网络划分进行巧妙地联合部署,提出了"域间单播 域内组播"或"域间组播 域内单播"的新型多层联合组通信模型,为下一代网络的组通信模型发展提供了一种全新的技术途径.性能分析表明,多层联合组通信模型继承了单层组通信模型的技术优势,改善了其存在的技术缺陷,在时延、抖动和丢包率等关键性能指标上均要明显优于目前的单播通信模型.     

A novel pricing approach to support QoS in 3G networks

Pricing in 3G and other communication networks may control and manage the utilisation of network resources. The available network resources get strained with increased usage levels, which results in poor service to the users. Most users prefer receiving high quality services at affordable costs. This requires the provision of QoS guarantees for network services at a low cost. In a real business scenario, this relationship is hard to achieve; moreover revenue sources for network operators have been shifting from the provision of network access to provisioning of rich services, e.g. multimedia services. To attain a functional compromise, we propose a pricing scheme that relies on service profiles to manage resource utilisation in a DiffServ-enabled 3G network. The service profiles define the QoS achieved for accessing services through a common resource pool, in which resource sharing is used to maximise network resource utilisation, user satisfaction and profits for the network operators. In an NGN scenario users would select pricing profiles according to their budgets, and the network will map these profiles to a set of QoS options that may translate to the choice of an access network for service access. In this paper, we present the mathematical model of the proposed pricing scheme, the proposed design of an evaluation framework, QoS performance results, and a service provisioning scenario illustrating the applicability of the proposed pricing scheme.     

A simple model and a distributed architecture for realizing one-stop e-government

In this paper, we propose a generic model for one-stop e-government and a distributed architecture for its implementation. The model follows a very basic paradigm: the public administration is composed of an unstructured network of entities that upload and download information objects to/from each other and to/from service repositories in order to deliver client-centered services. The architecture is based on widely available technologies such as HTTP, SSL, XML and PKI and it supports the implementation of life events, single access points, concurrent providers and integrated delivery channels. We argue that the proposed architecture permits the interconnection of almost any kind of government body and that it establishes a common ground upon which new standardization levels can be built. As a starting point, we also define a set of general requirements for one-stop e-government.     

Internet服务管理技术综述

1 服务与服务的分类经常提到服务这个概念,那么到底什么是服务呢?文[1]对服务进行了定义:服务就是服务提供方向一个或多个所服务的用户提供的一组实际能力。为研究之便,我们将服务分成两类:一类是传输服务,另一类是应用服务。这两种服务并不完全独立,它们是相互依存的,其中传输服务是应用服务的基础与保证,而应用服务是对传输服务的一种增值与体现。应用     

4CaaSt marketplace: An advanced business environment for trading cloud services

As Clouds mature and become ubiquitous, marketplace environments are developed facilitating the provision of services in a manner that emphasizes on the modular composition of individual services across different providers that crosscut the cloud service stack layers (i.e. composition of XaaS) to fulfil customers’ requirements. Besides acting as intermediaries for the search, selection and trading of services, such marketplaces should also support the complete service lifecycle and the consolidation of offerings from different providers with varying and often contradicting business goals. In this paper we present a one-stop cloud marketplace solution that addresses the aforementioned challenges while enabling the simulation of different business cases to optimize service offerings according to a wide and dynamic set of parameters. Moreover, the proposed solution introduces advanced aggregated price models and integrates a new resolution approach that incorporates business intelligence into the search and selection processes. We also demonstrate the operation of the implemented approach and evaluate its effectiveness using a real-world scenario, based on a taxi fleet management application.     

面向QoS的域间实时流覆盖组播方法研究

针对跨域远程协作中的实时流通信质量问题,构建了实时流服务网格（LSSG）,这是一个可扩展的且面向用户QoS需求的覆盖组播通信中间件结构,LSSG服务由网络服务提供商策略部署的服务代理（SvB）提供。论文主要采用面向QoS的域间覆盖组播算法（QIOM）来组织SvB建立实时流组播服务树,根据用户服务质量请求提供跨自治系统的实时流组通信服务,将域间资源管理转变为流媒体应用的动态协同服务管理。仿真结果表明QIOM能有效地发现和提供QoS满意的覆盖服务及实现SvB间的覆盖流量负载平衡。     

Designing Connection Oriented Networks for Multi-Domain Path Resilience

A challenge in network management and control is the ability to account for multi-domain requirements in the network planning process. Especially in Connection Oriented Networks where multi-domain path finding is a critical issue, networks need to be designed in such a manner as to restrict the possibility of erroneous inter-domain path selection. In this paper we propose per-domain topology design considerations that would leverage accurate disjoint path computations in a multi-domain environment, covering requirements of end-to-end path resiliency. In multi-domain environments state information between domains is heavily aggregated, hiding internal topology details dictated by scalability concerns, but also by restrictive domain administration policies for privacy, and security. Disjoint path finding is strongly affected by the aggregation techniques, since they do not provide information on path overlap. To handle this issue we introduce a metric, the Overlap Factor (OF), that quantifies path overlap in domains. The OF can be passed as an additional parameter of the inter-domain information exchange model to evaluate disjoint end-to-end paths. Alternatively, if domains were appropriately designed, this additional parameter might not be needed in evaluating resilient pairs of inter-domain paths. We based our recommended topology design algorithm on exploiting locally known OF values within the context of Genetic Algorithms. Extensive simulations confirm that domains designed using our proposed algorithm, result into accurate multi-domain disjoint path identification, with a high success ratio compared to networks that are designed without inter-domain considerations.     

The WSLA Framework: Specifying and Monitoring Service Level Agreements for Web Services

We describe a novel framework for specifying and monitoring Service Level Agreements (SLA) for Web Services. SLA monitoring and enforcement become increasingly important in a Web Service environment where enterprise applications and services rely on services that may be subscribed dynamically and on-demand. For economic and practical reasons, we want an automated provisioning process for both the service itself as well as the SLA managment system that measures and monitors the QoS parameters, checks the agreed-upon service levels, and reports violations to the authorized parties involved in the SLA management process. Our approach to these issues is presented in this paper. The Web Service Level Agreement (WSLA) framework is targeted at defining and monitoring SLAs for Web Services. Although WSLA has been designed for a Web Services environment, it is applicable as well to any inter-domain management scenario, such as business process and service management, or the management of networks, systems and applications in general. The WSLA framework consists of a flexible and extensible language based on XML Schema and a runtime architecture comprising several SLA monitoring services, which may be outsourced to third parties to ensure a maximum of objectivity. WSLA enables service customers and providers to unambiguously define a wide variety of SLAs, specify the SLA parameters and the way they are measured, and relate them to managed resource instrumentations. Upon receipt of an SLA specification, the WSLA monitoring services are automatically configured to enforce the SLA. An implementation of the WSLA framework, termed SLA Compliance Monitor, is publicly available as part of the IBM Web Services Toolkit.     

Optimization of virtual resource management for cloud applications to cope with traffic burst

Being the latest computing paradigm, cloud computing has proliferated as many IT giants started to deliver resources as services. Thus application providers are free from the burden of the low-level implementation and system administration. Meanwhile, the fact that we are in an era of information explosion brings certain challenges. Some websites may encounter a sharp rising workload due to some unexpected social concerns, which make these websites unavailable or even fail to provide services in time. Currently, a post-action method based on human experience and system alarm is widely used to handle this scenario in industry, which has shortcomings like reaction delay. In our paper, we want to solve this problem by deploying such websites on cloud, and use features of the cloud to tackle it. We present a framework of dynamic virtual resource management in clouds, to cope with traffic burst that applications might encounter. The framework implements a whole work-flow from prediction of the sharp rising workload to a customized resource management module which guarantees the high availability of web applications and cost-effectiveness of the cloud service providers. Our experiments show the accuracy of our workload forecasting method by comparing it with other methods. The 1998 World Cup workload dataset used in our experiment reveals the applicability of our model in the specific scenarios of traffic burst. Also, a simulation-based experiment is designed to indicate that the proposed management framework detects changes in workload intensity that occur over time and allocates multiple virtualized IT resources accordingly to achieve high availability and cost-effective targets.     

域间路由连通不完全性分析

论文从应用需求的角度出发,研究了分布式应用系统与网络层端到端连接性之间的关系,认为分布式系统的模型和部署应独立于网络层端到端连接。指出目前Internet域间路由中AS之间路由策略独立定义和实施对这种独立性带来了不利影响,它导致Internet跨域的端到端连接是连通不完全的。并试图提出初步的解决思路和方案。     

An enhanced network service pricing model considering network externalities

In this paper, we provide an evaluation model for marketable quality and profitability. We define the marketable quality as a qualitative aspect of profitability. Not always there is a clear tradeoff relation between marketable quality and profitability. Therefore, it is important to discover how to increase the profitability by enhancing marketable quality. We apply the real values of some leading manufacturing Japanese corporations to our proposed model to analyze its accuracy. From the analysis, we found that theoretical and real standard values of the marketable quality indicator were both 0.6. This shows that the proposed model has a good approximation. From the fair relation of network service providers and consumers, we present the network pricing guidelines for the maximum profitability, while enhancing the marketable quality. Also, we enhance our proposed network service pricing model considering network externalities.     

Event-Based Interaction Management for Composite E-Services in eFlow

The Web is rapidly becoming the platform through which many companies deliver e-services to businesses and individual customers. E-Services are typically delivered in their primitive forms, called basic services. However, today's business environment creates the opportunity for providing value-added, integrated services, delivered by composing existing e-services, possibly offered by different providers.In order to enable organizations to pursue this business opportunity we have developed eFlow, a model and architecture that support the specification, enactment, and management of composite e-services, modeled as processes that are enacted by a process engine. In this paper we focus on one of the most important and innovative aspects of eFlow: that of the integration between service composition and event management. In particular, we extend classic service composition model by allowing composite services to publish and receive events. This capability enables composite services to dynamically exchange data with other applications (in the form of event parameters), to synchronize service invocations with the occurrence of (external or internal) events, and to handle exceptions occurring during service execution. One of our main objectives has been that of defining a model that is easy to understand and easy to use. Indeed, all types of events are handled in the same fashion from the user perspective, and high-level constructs are provided to handle critical events such as those related to time management. Finally, we show how the proposed approach can be implemented by integrating existing technologies.     

Inter-domain policy violations in multi-hop overlay routes: Analysis and mitigation

The Internet is a complex structure arising from the interconnection of numerous autonomous systems (AS), each exercising its own administrative policies to reflect the commercial agreements behind the interconnection. However, routing in service overlay networks is quite capable of violating these policies to its advantage. To prevent these violations, we see an impending drive in the current Internet to detect and filter overlay traffic. In this paper, we first present results from a case study overlay network, constructed on top of PlanetLab, that helps us gain insights into the frequency and characteristics of the different inter-domain policy violations. Further, we investigate the impact of two types of overlay traffic filtering that aim to prevent these routing policy violations: blind filtering and policy-aware filtering. We show that such filtering can be detrimental to the performance of overlay routing. We next consider two approaches that allow the overlay network to realize the full advantage of overlay routing in this context. In the first approach, overlay nodes are added so that good overlay paths do not represent inter-domain policy violations. In the second approach, the overlay acquires permits from certain ASes that allow certain policy violations to occur. We develop a single cost-sharing framework that allows the incorporation of both approaches into a single strategy. We formulate and solve an optimization problem that aims to determine how the overlay network should allocate a given budget between paying for additional overlay nodes and paying for permits (transit and exit) to ASes. We illustrate the use of this approach on our case study overlay network and evaluate its performance under varying network characteristics.