SPAD: A distributed middleware architecture for QoS enhanced alternate path discovery

In the next generation Internet, the network will evolve from a plain communication medium into one that provides endless services to the users. These services will be composed of multiple cooperative distributed application elements. We name these services overlay applications. The cooperative application elements within an overlay application will build a dynamic communication mesh, namely an overlay association. The Quality of Service (QoS) perceived by the users of an overlay application greatly depends on the QoS experienced on the communication paths of the corresponding overlay association. In this paper, we present super-peer alternate path discovery (SPAD), a distributed middleware architecture that aims at providing enhanced QoS between end-points within an overlay association. To achieve this goal, SPAD provides a complete scheme to discover and utilize composite alternate end-to-end paths with better QoS than the path given by the default IP routing mechanisms.     

Combined Asynchronous/Synchronous Packet Switching Architecture: QoS Guarantees for Integrated Parallel Computing and Real-Time Traffic

This paper focuses on the challenging problem of integrating real-time traffic with data traffic on the same network, while having predictable quality of service (QoS) guarantees. Predictable QoS guarantees mean both deterministic and probabilistic (with a known probability distribution) functions of loss, delay, and jitter. As of today there are only limited solutions to this problem. This work presents, to the best of our knowledge, the first coherent system solution, for combining, on one hand, bursty data traffic with deterministic no loss due to congestion, and on the other hand, periodic real-time traffic with deterministic bandwidth guarantees, constant jitter, and bounded delay. The principles of this architecture facilitate the implementation of a scalable multimedia system that will combine or integrate distributed/parallel computing (e.g., over a network of PC/workstations) with real-time applications (e.g., interactive video teleconferencing).     

An adaptive and QoS-based spectrum awareness framework for CR networks

The Cognitive Radio (CR) networks have the capability to be aware of the licensed spectrum and to solve the inefficient usage of the vacant bands in an opportunistic manner. Thus, a spectrum awareness framework must be designed by considering the spectrum availability, the Primary User (PU) interference avoidance and the heterogeneous Quality of Service (QoS) requirements of CR users (CrUs). Considering these challenges, the main contribution of this paper is to design a complete framework for the spectral awareness in CR networks achieving higher spectrum utilization and fairness. Specifically, a PU Presence Map (PuM) is built for the PU interference avoidance. The QoS requirements of CR users are classified using a Request Map, ReM. An admission control is proposed to stabilize the heterogeneous QoS requirements according to PuM and ReM. Moreover, the adaptiveness of the framework is provided by continuous monitoring of the spectrum against dynamic variations. The simulations demonstrate that the proposed spectrum awareness framework maximizes the available spectrum utilization while maintaining the fairness.     

Assessment and improvement of quality of service in wireless networks using fuzzy and hybrid genetic-fuzzy approaches

Fuzzy and hybrid genetic-fuzzy approaches were used to assess and improve quality of service (QoS) in simulated wireless networks. Three real-time audio and video applications were transmitted over the networks. The QoS provided by the networks for each application was quantitatively assessed using a fuzzy inference system (FIS). Two methods to improve the networks’ QoS were developed. One method was based on a FIS mechanism and the other used a hybrid genetic-fuzzy system. Both methods determined an optimised value for the minimum contention window (CW _min) in IEEE 802.11 medium access control (MAC) protocol. CW _min affects the time period a wireless station waits before it transmits a packet and thus its value influences QoS. The average QoS for the audio and video applications improved by 42.8% and 14.5% respectively by using the FIS method. The hybrid genetic-fuzzy system improved the average QoS for the audio and video applications by 35.7% and 16.5% respectively. The study indicated that the devised methods were effective in assessing and significantly improving QoS in wireless networks.     

Efficient planning for top-K Web service composition

This paper proposes a novel approach based on the planning-graph to solve the top-k QoS-aware automatic composition problem of semantic Web services. The approach includes three sequential stages: a forward search stage to generate a planning-graph to reduce the search space of the following two stages greatly, an optimal local QoS calculating stage to compute all the optimal local QoS values of services in the planning, and a backward search stage to find the top-K composed services with optimal QoS values according to the planning-graph and the optimal QoS value. In order to validate the approach, experiments are carried out based on the test sets offered by the WS-Challenge competition 2009. The results show that the approach can find the same optimal solution as the champion system from the competition but also can provide more alternative solutions with the optimal QoS for users.     

Make it personal: A social explanation system applied to group recommendations

Recommender systems help users to identify which items from a variety of choices best match their needs and preferences. In this context, explanations act as complementary information that can help users to better comprehend the system’s output and to encourage goals such as trust, confidence in decision-making or utility. In this paper we propose a Personalized Social Individual Explanation approach (PSIE). Unlike other expert systems the PSIE proposal novelly includes explanations about the system’s group recommendation and explanations about the group’s social reality with the goal of inducing a positive reaction that leads to a better perception of the received group recommendations. Among other challenges, we uncover a special need to focus on “tactful” explanations when addressing users’ personal relationships within a group and to focus on personalized reassuring explanations that encourage users to accept the presented recommendations. Besides, the resulting intelligent system significatively increases users’ intent (likelihood) to follow the recommendations, users’ satisfaction and the system’s efficiency and trustworthiness.     

Analyzing the performance of deferred reservations

This paper studies the performance of deferred resource reservation in data networks. Conventional resource reservation protocols, such as PNNI and RSVP adopt an all-or-nothing approach, where partially acquired resources must be released if resources are not available at all links on the chosen path. During periods of high network load, this leads users to retry requests repeatedly, adding control traffic at exactly the time when the network’s capacity to process that control traffic is exhausted. Deferred REServation (DRES) can significantly improve performance by reducing the overall call rejection probability, allowing more traffic to be carried, using the same resources. Call admissibility is increased by deferring requests at routers for a limited period of time until resources become available. The paper includes analytical models that predict the blocking probability on a DRES multiplexor and on a multi-hop path, and simulation results for substantial network configurations, using several QoS routing methods. The results show that DRES can provide substantial performance gains over traditional reservations (upto 50% with QoS routing enabled and upto an order of magnitude for non-QoS traditional routing).     

Recommendation of optimized information seeking process based on the similarity of user access behavior patterns

Differing from many studies of recommendation that provided the final results directly, our study focuses on providing an optimized process of information seeking to users. Based on process mining, we propose an integrated adaptive framework to support and facilitate individualized recommendation based on the gradual adaptation model that gradually adapts to a target user’s transition of needs and behaviors of information access, including various search-related activities, over different time spans. In detail, successful information seeking processes are extracted from the information seeking histories of users. Furthermore, these successful information seeking processes are optimized as a series of action units to support the target users whose information access behavior patterns are similar to the reference users. Based on these, the optimized information seeking processes are navigated to the target users according to their transitions of interest focus. In addition to describing some definitions and measures introduced, we go further to present an optimized process recommendation model and show the system architecture. Finally, we discuss the simulation and scenario for the proposed system.     

Cooperative radio resource management framework for future IP-based multiple radio access technologies environment

Heterogeneity and convergence are two distinctive connotations of future wireless networks emanated from International Telecommunications Union (ITU)’s vision of Optimally Connected, Anywhere, Anytime. Multiple access networks, multiple terminals and multiple services are expected to converge in a manner where heterogeneity can be exploited to realize this ultimate goal. This raises the importance of radio resource management (RRM) for a multiple radio access technologies (multi-RAT) environment, where coalitions of heterogeneous access networks are each connected to a common Internet Protocol (IP)-based core network. In this article, we develop a cooperative RRM framework for future IP-based multi-RAT environment to coordinate better utilization of radio resources in an opportunistic yet altruistic manner. We motivate the importance of cooperation which can exploit heterogeneity as an enabler to improve system capacity and quality of service (QoS) of users. We exemplify the proof of concept based on a heterogeneous multiple access points (multi-AP) wireless local area network (WLAN) and argue that our technology agnostic approach is readily applicable to future IP-based multi-RAT environment. We demonstrate that our cooperative RRM framework benefits from the unified actions of joint optimization and results in a QoS-balanced system by enabling different functional entities to form synergies and multiple access networks to interact. We further show that a QoS-balanced system has salient traits of providing statistical QoS guarantee to support demanding multimedia applications while maximizing overall system capacity. Consequently, we advocate the notion of QoS balancing as criterion to quantify the state of balance in future IP-based multi-RAT environment.     

QoS-aware service selection via collaborative QoS evaluation

We present in this paper a novel collaborative filtering based scheme for evaluating the QoS of large scale Web services. The proposed scheme automates the process of assessing the QoS of a priori unknown service providers and thus facilitates service users in selecting services that best match their QoS requirements. Most existing service selection approaches ignore the great diversity in the service environment and assume that different users receive identical QoS from the same service provider. This may lead to inappropriate selection decisions as the assumed QoS may deviate significantly from the one actually received by the users. The collaborative filtering based approach addresses this issue by taking the diversity into account instead of uniformly applying the same QoS value to different users. They predict a user’s QoS on an unknown service by exploiting the historical QoS experience of similar users. Nevertheless, when only limited historical QoS data is available, these approaches either fail to make any predictions or make very poor ones. The cornerstone of the proposed QoS evaluation scheme is a Relational Clustering based Model (or RCM) that effectively addresses the data scarcity issue as stated above. Experimental results on both real and synthetic datasets demonstrate that the proposed scheme can more accurately predict the QoS on unknown service providers. The efficient performance also makes it applicable to QoS evaluation for large scale Web services.     

The QoS-based MCDM system for SaaS ERP applications with Social Network

Cloud computing delivers almost all of its services including software, user’s data, system resources, processes and their computation over the Internet. Cloud computing consists of three main classes; Software as a Service, Infrastructure as a Service and Platform as a Service. Using Software as a Service (SaaS), users are able to rent application software and databases which they then install onto their computer in the traditional way. In the Enterprise Resource Planning (ERP) system, the system service environment changed so as to allow the application of the SaaS in the cloud computing environment. This change was implemented in order to provide the ERP system service to users in a cheaper, more convenient and efficient form through the Internet as opposed to having to set up their own computer. Recently many SaaS ERP packages are available on the Internet. For this reason, it is very difficult for users to find the SaaS ERP package that would best suit their requirements. The QoS (Quality of Service) model can provide a solution to this problem. However, according to recent research, not only quality attributes’ identification for SaaS ERP, but also a process for finding and recommending software in the cloud computing environment, has proved to be lacking. In this paper, we propose a QoS model for SaaS ERP. The proposed QoS model consists of 6 criteria; Functionality, Reliability, Usability, Efficiency, Maintainability and Business. Using this QoS model, we propose a Multi Criteria Decision Making (MCDM) system that finds the best fit for the SaaS ERP in the cloud computing environment and makes recommendations to users in priority order. In order to organize the quality clusters, we organized an expert group and got their opinion to organize the quality clusters using Social Network Group. Social Networks can be used efficiently to get opinion by various types of expert groups. In order to establish the priority, we used pairwise comparisons to calculate the priority weights of each quality attribute while accounting for their interrelation. Finally, using the quality network model and priority weights, this study evaluated three types of SaaS ERPs. Our results show how to find the most suitable SaaS ERPs according to their correlation with the criteria and to recommend a SaaS ERP package which best suits users’ needs.     

A new approach to dynamic bandwidth allocation in Quality of Service networks: Performance and bounds

Efficient dynamic resource provisioning algorithms are necessary to the development and automation of Quality of Service (QoS) networks. The main goal of these algorithms is to offer services that satisfy the QoS requirements of individual users while guaranteeing at the same time an efficient utilization of network resources.In this paper we introduce a new service model that provides per-flow bandwidth guarantees, where users subscribe for a guaranteed rate; moreover, the network periodically individuates unused bandwidth and proposes short-term contracts where extra-bandwidth is allocated and guaranteed exclusively to users who can exploit it to transmit at a rate higher than their subscribed rate.To implement this service model we propose a dynamic provisioning architecture for intra-domain Quality of Service networks. We develop a set of dynamic on-line bandwidth allocation algorithms that take explicitly into account traffic statistics and users’ utility functions to increase users’ benefit and network revenue.Further, we propose a mathematical formulation of the extra-bandwidth allocation problem that maximizes network revenue. The solution of this model allows to obtain an upper bound on the performance achievable by any on-line bandwidth allocation algorithm.We demonstrate through simulation in realistic network scenarios that the proposed dynamic allocation algorithms are superior to static provisioning in providing resource allocation both in terms of total accepted load and network revenue, and they approach, in several network scenarios, the ideal performance provided by the mathematical model.     

Accomplishing the layered modular architecture in digital innovation: The case of the car’s driver information module

Architectural theory of digital innovation contends that, to enhance physical products with digital capabilities, a layered modular architecture is required. This architecture hybridizes hierarchically arranged components of physical products with modules of digital functionality configured into layers. Despite considerable research adopting this architectural perspective on digital innovation, questions of how this hybrid architecture is accomplished organizationally and technologically lack both conceptual clarity and empirical illustration. Noting pervasive tensions that characterize digital innovation efforts and the contradictions between hierarchical and layered modular configurations, this paper seeks to answer the following research question: Given that the layered modular architecture needs to hybridize modular arrangements with opposing logics, how is it accomplished?Employing the concepts of digitalization, physical product hierarchy and digital control system to better theorize a product architecture’s movement from a modular to a layered modular architecture accompanied by organizational structures that enable this change, we abductively analyze the increasing digitization of a car’s Driver Information Module (DIM) over a 10 year period. We conclude by proposing three transformations through which the layered modular architecture is accomplished.     

Dynamic bandwidth allocation for 3G wireless systems—A fuzzy approach

3G Wireless systems are to support multiple classes of traffic with widely different characteristics and quality of service (QoS) requirements. A major challenge in this system is to guarantee the promised QoS for the admitted users, while maximizing the resource allocation through dynamic resource sharing. In the case of multimedia call, each of the services has its own distinct QoS requirements concerning probability of blocking (P_B), service access delay (SAD), and access delay variation (ADV). The 3G wireless system attempts to deliver the required QoS by allocating appropriate resources (e.g. bandwidth, buffers), and bandwidth allocation is a key in achieving this. Dynamic bandwidth allocation policies reported so far in the literature deal with audio source only. They do not consider QoS requirements. In this work, a fuzzy logic (FL)-based dynamic bandwidth allocation algorithm for multimedia services with multiple QoS (P_B, SAD, ADV, and the arrival rate) requirements are presented and analyzed. Here, each service can declare a range of acceptable QoS levels (e.g. high, medium, and low). As QoS demand varies, the proposed algorithm allocates the best possible bandwidth to each of the services. This maximizes the utilization and fair distribution of resources. The proposed allocation method is validated in a variety of scenarios. The results show that the required QoS can be obtained by appropriately tuning the fuzzy logic controller (FLC).     

Efficient load-balancing routing for wireless mesh networks

Wireless mesh networks (WMNs) consist of static wireless routers, some of which, called gateways, are directly connected to the wired infrastructure. User stations are connected to the wired infrastructure via wireless routers. This paper presents a simple and effective management architecture for WMNs, termed configurable access network (CAN). Under this architecture, the control function is separated from the switching function, so that the former is performed by an network operation center (NOC) which is located in the wired infrastructure. The NOC monitors the network topology and user performance requirements, from which it computes a path between each wireless router and a gateway, and allocates fair bandwidth for carrying the associated traffic along the selected route. By performing such functions in the NOC, we offload the network management overhead from wireless routers, and enable the deployment of simple/low-cost wireless routers. Our goal is to maximize the network utilization by balancing the traffic load, while providing fair service and quality of service (QoS) guarantees to the users. Since, this problem is NP-hard, we devise approximation algorithms that provide guarantees on the quality of the approximated solutions against the optimal solutions. The simulations show that the results of our algorithms are very close to the optimal solutions.     

A novel QoS model and computation framework in web service selection

With the rapid development of e-commerce over Internet, web services have attracted much attention in recent years. Nowadays, enterprises are able to outsource their internal business processes as services and make them accessible via the Web. Then they can dynamically combine individual services to provide new value-added services. With the increasing number of web services having equivalent functionality, the binding procedure is driven by some non-functional, Quality of Service (QoS) criteria, such as the money cost, response time, reputation, reliability or a trade-off between them. Thus, an important problem is, given QoS constraints, how to aggregate and leverage individual service??s QoS information to derive the optimal QoS of the composite service. In this paper, we propose a novel QoS model for performing flexible service selection. The key idea of the model is to relax users?? QoS constraints and try to find the most possible services satisfying users?? QoS requirements. Based on the proposed QoS framework, we develop various algorithms for making service selection on individual and composite services. We also introduce a top-k ranking strategy to reflect a user??s personalized requirements. Experimental evaluation shows the proposed QoS model is efficient and practical.     

An XML-based Quality of Service Enabling Language for the Web

In this paper, we introduce an XML-based hierarchical QoS markup language, called HQML, to enhance distributed multimedia applications on the World Wide Web (WWW) with quality of service (QoS) capability. The design ofHQML is based on two observations: (1) the absence of a systematic QoS specification language, that can be used by distributed multimedia applications on the WWW to utilize the state-of-the-art QoS management technology and (2) the power and popularity of XML to deliver richly structured contents over the Web. HQML allows distributed multimedia applications to specify all kinds of application-specific QoS policies and requirements. During runtime, the HQML Executor translates the HQML file into desired data structures and cooperates with the QoS proxies that assist applications in end-to-end QoS negotiation, setup and enforcement. In order to make QoS services tailored toward user preferences and meet the challenges of uncertainty in the distributed heterogeneous environments, the design of HQML is featured as interactive andflexible . In order to allow application developers to create HQML specifications correctly and easily, we have designed and developed a unified visual QoS programming environment, called QoSTalk. In QoSTalk, we adopt a grammatical approach to perform consistency check on the visual QoS specifications and generate HQML files automatically. Finally, we introduce the distributed QoS compiler, which performs the automatic mappings between application- and resource-level QoS parameters to relieve the application developer of the burden of dealing with low-level QoS specifications.     

Incorporating behavioral trust theory into system development for ubiquitous applications

Trust has been shown to be a key factor for technology adoption by users, that is, users prefer to use applications they trust. While existing literature on trust originating in computer science mostly revolves around aspects of information security, authentication, etc., research on trust in automation—originating from behavioral sciences—almost exclusively focuses on the sociotechnical context in which applications are embedded. The behavioral theory of trust in automation aims at explaining the formation of trust, helping to identify countermeasures for users’ uncertainties that lead to lessened trust in an application. We hence propose an approach to augment the system development process of ubiquitous systems with insights into behavioral trust theory. Our approach enables developers to derive design elements that help foster trust in their application by performing four key activities: identifying users’ uncertainties, linking them to trust antecedents from theory, deducting functional requirements and finally designing trust-supporting design elements (TSDEs). Evaluating user feedback on two recommender system prototypes, gathered in a study with over 160 participants, we show that by following our process, we were able to derive four TSDEs that helped to significantly increase the users’ trust in the system.     

A QoS model for collaboration through Distributed Virtual Environments

Today’s virtual environments are expected to be distributed to allow collaboration for common purposes. However, they must ensure a high level of Quality of Service (QoS) to the user, especially in an open context with unknown, a priori, man-in-the-loop event occurrence. This paper presents our Distributed Virtual Environment Collaboration Model (DVECOM) and its implementation which aims to provide an end-user QoS support for distributed virtual reality applications. This model aims to reconcile openness and real-time requirements for collaborative relationships using virtual environments. Real-time requirements ensure the logical synchronization between the displayed scenes of the same virtual world on a set of distributed machines. The DVECOM model is based partially upon COREMO concepts and further work done in the context of the Amusement European Esprit project.DVECOM integrates QoS provision and management. The major idea is to guarantee the consistency of scene rendering and the synchronization of the display from the user point of view. The other idea is to auto-adapt rendering in accordance with the retained strategy, ensuring best effort and least suffering virtual world rendering. Representation degradation is driven by the users’ choices and is assisted by the system. The receiver-side protocol is based upon end-user preferences, physical level capability information, as well as pertinence of notification to each client (contextual end-user information). The model should be able to guarantee logical consistency and synchronization of virtual world distributed displays, with the least rendering degradation possible. When available, such guarantees would make it possible to use DVE out of a closed, oversized, very restricted context for industrial collaborative applications with an expected QoS.