/pdf/a-break-in-the-clouds-towards-a-cloud-definition-svovsw1r5a.pdf

A Break in the Clouds: Towards a Cloud Definition

In this Chapter, we imagine a decision maker (or a group of experts) trying to establish or examine fair procedures to combine opinions about alternatives related to different points of view.

Multiple criteria decision making

In advanced service oriented systems, complex applications, described as abstract business processes, can be executed by invoking a number of available Web services. End users can specify different preferences and constraints and service selection can be performed dynamically identifying the best set of services available at runtime. In this paper, we introduce a new modeling approach to the Web service selection problem that is particularly effective for large processes and when QoS constraints are severe. In the model, the Web service selection problem is formalized as a mixed integer linear programming problem, loops peeling is adopted in the optimization, and constraints posed by stateful Web services are considered. Moreover, negotiation techniques are exploited to identify a feasible solution of the problem, if one does not exist. Experimental results compare our method with other solutions proposed in the literature and demonstrate the effectiveness of our approach toward the identification of an optimal solution to the QoS constrained Web service selection problem

/pdf/adaptive-service-composition-in-flexible-processes-2v4wr8la29.pdf

Adaptive Service Composition in Flexible Processes

Lecture Notes in Economics and Mathematical Systems

We survey recent advances in algorithms for route planning in transportation networks. For road networks, we show that one can compute driving directions in milliseconds or less even at continental scale. A variety of techniques provide different trade-offs between preprocessing effort, space requirements, and query time. Some algorithms can answer queries in a fraction of a microsecond, while others can deal efficiently with real-time traffic. Journey planning on public transportation systems, although conceptually similar, is a significantly harder problem due to its inherent time-dependent and multicriteria nature. Although exact algorithms are fast enough for interactive queries on metropolitan transit systems, dealing with continent-sized instances requires simplifications or heavy preprocessing. The multimodal route planning problem, which seeks journeys combining schedule-based transportation (buses, trains) with unrestricted modes (walking, driving), is even harder, relying on approximate solutions even for metropolitan inputs.

/pdf/route-planning-in-transportation-networks-k0typz8i4k.pdf

Route Planning in Transportation Networks

Quality of service (QoS) can be a critical element for achieving the business goals of a service provider, for the acceptance of a service by the user, or for guaranteeing service characteristics in a composition of services, where a service is defined as either a software or a software-support (i.e., infrastructural) service which is available on any type of network or electronic channel. The goal of this article is to compare the approaches to QoS description in the literature, where several models and metamodels are included. consider a large spectrum of models and metamodels to describe service quality, ranging from ontological approaches to define quality measures, metrics, and dimensions, to metamodels enabling the specification of quality-based service requirements and capabilities as well as of SLAs (Service-Level Agreements) and SLA templates for service provisioning. Our survey is performed by inspecting the characteristics of the available approaches to reveal which are the consolidated ones and which are the ones specific to given aspects and to analyze where the need for further research and investigation lies. The approaches here illustrated have been selected based on a systematic review of conference proceedings and journals spanning various research areas in computer science and engineering, including: distributed, information, and telecommunication systems, networks and security, and service-oriented and grid computing.

/pdf/a-survey-on-service-quality-description-45tlign22h.pdf

A survey on service quality description

Intrusion detection systems (IDSs) play a pivotal role in computer security by discovering and repealing malicious activities in computer networks. Anomaly-based IDS, in particular, rely on classification models trained using historical data to discover such malicious activities. In this paper, an improved IDS based on hybrid feature selection and two-level classifier ensembles are proposed. A hybrid feature selection technique comprising three methods, i.e., particle swarm optimization, ant colony algorithm, and genetic algorithm, is utilized to reduce the feature size of the training datasets (NSL-KDD and UNSW-NB15 are considered in this paper). Features are selected based on the classification performance of a reduced error pruning tree (REPT) classifier. Then, a two-level classifier ensemble based on two meta learners, i.e., rotation forest and bagging, is proposed. On the NSL-KDD dataset, the proposed classifier shows 85.8% accuracy, 86.8% sensitivity, and 88.0% detection rate, which remarkably outperform other classification techniques recently proposed in the literature. The results regarding the UNSW-NB15 dataset also improve the ones achieved by several state-of-the-art techniques. Finally, to verify the results, a two-step statistical significance test is conducted. This is not usually considered by the IDS research thus far and, therefore, adds value to the experimental results achieved by the proposed classifier.

/pdf/tse-ids-a-two-stage-classifier-ensemble-for-intelligent-q5dy8qhb8h.pdf

TSE-IDS: A Two-Stage Classifier Ensemble for Intelligent Anomaly-Based Intrusion Detection System

The processes with adaptive Web services framework couples design-time and runtime mechanisms to flexibly and adoptively execute managed Web-services-based business processes.

PAWS: A Framework for Executing Adaptive Web-Service Processes

The extensive adoption of Web service-based applications in dynamic business scenarios, such as on-demand computing or highly reconfigurable virtual enterprises, advocates for methods and tools for the management of Web service nonfunctional aspects, such as Quality of Service (QoS). Concerning contracts on Web service QoS, the literature has mostly focused on the contract definition and on mechanisms for contract enactment, such as the monitoring of the satisfaction of negotiated QoS guarantees. In this context, this article proposes a framework for the automation of the Web service contract specification and establishment. An extensible model for defining both domain-dependent and domain-independent Web service QoS dimensions and a method for the automation of the contract establishment phase are proposed. We describe a matchmaking algorithm for the ranking of functionally equivalent services, which orders services on the basis of their ability to fulfill the service requestor requirements, while maintaining the price below a specified budget. We also provide an algorithm for the configuration of the negotiable part of the QoS Service-Level Agreement (SLA), which is used to configure the agreement with the top-ranked service identified in the matchmaking phase. Experimental results show that, in a utility theory perspective, the contract establishment phase leads to efficient outcomes. We envision two advanced application scenarios for the Web service contracting framework proposed in this article. First, it can be used to enhance Web services self-healing properties in reaction to QoS-related service failures; second, it can be exploited in process optimization for the online reconfiguration of candidate Web services QoS SLAs.

A framework for QoS-based Web service contracting

In modern service economies, service provisioning needs to be regulated by complex SLA hierarchies among providers of heterogeneous services, defined at the business, software, and infrastructure layers. Starting from the SLA Management framework defined in the SLA@SOI EU FP7 Integrated Project, we focus on the relationship between establishment and monitoring of such SLAs, showing how the two processes become tightly interleaved in order to provide meaningful mechanisms for SLA management. We first describe the process for SLA establishment adopted within the framework; then,we propose an architecture for monitoring SLAs, which satisfies the two main requirements introduced by SLA establishment: the availability of historical data for evaluating SLA offers and the assessment of the capability to monitor the terms in a SLA offer.

/pdf/establishing-and-monitoring-slas-in-complex-service-based-3ze50srfaf.pdf

Marco Comuzzi

Papers

A survey on service quality description

TSE-IDS: A Two-Stage Classifier Ensemble for Intelligent Anomaly-Based Intrusion Detection System

PAWS: A Framework for Executing Adaptive Web-Service Processes

A framework for QoS-based Web service contracting

Establishing and Monitoring SLAs in Complex Service Based Systems