Web Scenario Research Articles

Integrating trust management and access control in data-intensive Web applications

The widespread diffusion of Web-based services provided by public and private organizations emphasizes the need for a flexible solution for protecting the information accessible through Web applications. A promising approach is represented by credential-based access control and trust management. However, although much research has been done and several proposals exist, a clear obstacle to the realization of their benefits in data-intensive Web applications is represented by the lack of adequate support in the DBMSs. As a matter of fact, DBMSs are often responsible for the management of most of the information that is accessed using a Web browser or a Web service invocation. In this article, we aim at eliminating this gap, and present an approach integrating trust management with the access control of the DBMS. We propose a trust model with a SQL syntax and illustrate an algorithm for the efficient verification of a delegation path for certificates. Our solution nicely complements current trust management proposals allowing the efficient realization of the services of an advanced trust management model within current relational DBMSs. An important benefit of our approach lies in its potential for a robust end-to-end design of security for personal data in Web scenario, where vulnerabilities of Web applications cannot be used to violate the protection of the data residing on the database server. We also illustrate the implementation of our approach within an open-source DBMS discussing design choices and performance impact.

A Query Formulation Language for the Data Web

We present a query formulation language (called MashQL) in order to easily query and fuse structured data on the web. The main novelty of MashQL is that it allows people with limited IT skills to explore and query one (or multiple) data sources without prior knowledge about the schema, structure, vocabulary, or any technical details of these sources. More importantly, to be robust and cover most cases in practice, we do not assume that a data source should have - an offline or inline - schema. This poses several language-design and performance complexities that we fundamentally tackle. To illustrate the query formulation power of MashQL, and without loss of generality, we chose the Data web scenario. We also chose querying RDF, as it is the most primitive data model; hence, MashQL can be similarly used for querying relational databases and XML. We present two implementations of MashQL, an online mashup editor, and a Firefox add on. The former illustrates how MashQL can be used to query and mash up the Data web as simple as filtering and piping web feeds; and the Firefox add on illustrates using the browser as a web composer rather than only a navigator. To end, we evaluate MashQL on querying two data sets, DBLP and DBPedia, and show that our indexing techniques allow instant user interaction.

Training Johnny to Authenticate (Safely)

The authors present the results of a long-term user study of site-based login mechanisms that train users to log in safely. Interactive site-identifying images received 70 percent detection rates, which is significantly better than the 20 percent received by the typical login ceremony. They also found that combining login bookmarks with interactive images and nonworking buttons or links (called negative training functions) achieved the best detection rates (82 percent) and overall resistance rates (93 percent). Because interactive custom images provide effective user training against phishing, the authors extended its authentication usages. The authors present an adaptive authentication mechanism based on recognition of multiple custom images, which can be used for different Web and mobile authentication scenarios. The mechanism relies on memorization of the custom images on each primary login, adaptively increasing the authentication difficulty on detection of impersonation attacks, and recognizing all images for fallback authentication.

Personalization of Automobile News Documents Using Genetic Algorithm Model

Recent technologies make it possible to know about anything that happens in any part of the world to be made available to any person at any place and at any time. In this direction the services provided by Yahoo, CNN, CNET etc. are enormous that cater to the needs for a greater part of the globe to acquire timely and informative news about anything. Though search engines and with various news providers, present web scenario is capable of providing information in variety of ways, it is a fact that not all news are relevant for all people. That is, user satisfaction as well as user preferences must be taken into account while providing news items. In this regard, the need for personalization arises whereby users can obtain relevant information of their interests through technologies. Personalized news provisions make the readers to get information of their choice, thereby the time involved in searching the news of their taste is greatly minimized. This paper focuses on the design of a personalized news provider (PNP) system for searching automobile news documents as per the user's interests using traditional and classical optimization method.

Dynamic Trust for Secure EShopping in Semantic Web

present scenario, electronic shopping has become a trend which is easy and time-saving. Such convenient services on web and the products provided by sellers are trustworthy or not are very important for buyers to know. Seller can even increase their product rating by acting as a buyer or can decrease the rating of his competitor's product. Also a buyer can also give the wrong feedback. So it is difficult to trust such e- products and user's feedback. In this paper, a dynamic trustworthy framework rectifies lack of static trust in semantic web scenario on the basis of the trust level of users (Buyers and Sellers). To achieve this, three agents are employed (namely Process Agent (PA), Detection Agent (DA) and Trust Calculation Agent (TCA)) for calculating dynamic trust in Semantic Web. These intelligent agents collectively restrict any imposter from increasing the fake trust value and hence furnish a genuine trust value dynamically.

Towards Checking Laws' Consistency through Ontology Design: The Case of Brazilian Vehicles' Laws

Official documents, and particularly legal ones like law codes, often contain ambiguities and/or inconsistencies, due to linguistic problems like polysemy, as well as ontological problems like underspecification, disagreements and/or false agreements. Such problems can be identified by formalizing the terminology of a domain in terms of an ontology. We show this phenomenon in a particular domain, the definition of different classes of vehicles. Defining accurately these different vehicle types shed light on some of these semantic deficiencies present in two Brazilian legal codes responsible for defining vehicles' categories in an unambiguous manner for many purposes, e.g. tax calculations, and, more importantly, to make e-government systems interoperate while taking laws into account in a Semantic Web scenario. In this work, we define a framework linking the linguistic and conceptual problems to semantic deficiencies and show how these deficiencies were identified during the vehicles' ontology construction.

MovieRemix: Having Fun Playing with Videos

The process of producing new creative videos by editing, combining, and organizing pre-existing material (e.g., video shots) is a popular phenomenon in the current web scenario. Known asremixor video remix, the produced video may have new and different meanings with respect to the source material. Unfortunately, when managing audiovisual objects, the technological aspect can be a burden for many creative users. Motivated by the large success of the gaming market, we propose a novel game and an architecture to make the remix process a pleasant and stimulating gaming experience. MovieRemix allows people to act like a movie director, but instead of dealing with cast and cameras, the player has to create a remixed video starting from a given screenplay and from video shots retrieved from the provided catalog. MovieRemix is not a simple video editing tool nor is a simple game: it is a challenging environment that stimulates creativity. To temp to play the game, players can access different levels of screenplay (original, outline, derived) and can also challenge other players. Computational and storage issues are kept at the server side, whereas the client device just needs to have the capability of playing streaming videos.

Exploring problem solving patterns and their impact on learning achievement in a blended learning environment

Blended learning, thoughtfully combining the best elements of online and face-to-face education, is likely to emerge as the predominant teaching model of the future. In this paper, we present a blended learning environment combining mobile learning, web-based learning, and classroom teaching to provide realistic, practical opportunities for learners and teachers to engage in problem solving activities. The purpose of this study was to explore problem solving patterns and their impact on learning achievement in a blended learning environment. Through quasi-experimental instruction, we collected all of the data of the learning processes from 34 students in a blended learning environment using classroom instruction, mobile and web scenarios. By combining cluster analysis and content analysis, we were able to identify three groups with distinct characteristics: the hybrid-oriented group, the technology-oriented group, and the efficiency-oriented group. Learners in the hybrid-oriented group used the classroom, mobile and web scenario almost equally. They displayed a regular manner in following the instructor’s teaching procedure, and tended to passively accept whatever the teacher said. Students in the technology-oriented group spent most of their time using mobile and web technologies but they revealed superficial problem solving abilities such as a lack of understanding and planning. The efficiency-oriented group was characterized by the efficient monitoring of learning processes. It was more task-oriented and performed better than the other two groups.

Euphausia mucronata: A keystone herbivore and prey of the Humboldt Current System

Abstract Euphausiids are important components of many ecosystems, especially in productive regions of temperate and high latitudes. The present paper makes the case that E. mucronata plays a keystone role in the food web of the Humboldt Current System (HCS) based on a synthesis of new and published data supporting its potential role as a primary grazer, as well as a principal prey for upper trophic level fish. E. mucronata is an endemic species, concentrated in the coastal upwelling belt of the HCS, with morpho-physiological adaptations to vertically migrate into the Oxygen Minimum Zone (OMZ). Within the 100-km coastal belt of the HCS it accounts for ca. 50% of the meso zooplankton wet weight in winter. In the mixed layer, it is a herbivore with high night ingestion rates (612.2 ng Chl eq ind−1 h−1 or 1013.9 μg C ind−1 d−1, in winter), and accounted for a 19.3% impact on primary production in winter, at an intermediate population abundance (3.8 ind m−3). At higher abundances (50 ind m−3) equivalent to swarms, impact on primary production could reach 254%. Additionally E. mucronata is a common prey of numerous upper trophic level predators. The diet of jack mackerel (Trachurus murphyi) off central Chile (34-39°S) indicates a striking dependence on E. mucronata prey (average of 75% of stomach content in weight). The fishing season off central Chile extended from austral fall (March–April) and continued at least until the end of austral winter (September). The average daily ration of jack mackerel was 17.4 g, which is equivalent to 2.3% of fish body weight per day. The total E. mucronata consumed in 1991 by the landed population of fish (3.7 million tons yr−1) amounted to 23.2 million tons yr−1. The total estimated population of jack mackerel that year (17.6 million tons) would have consumed ca. 110.2 million tons of E. mucronata. Based on stomach contents, consumption of E. mucronata by other nektonic predators off Chile and off Peru is also outstanding. Four different food web scenarios are offered for the northern and southern sectors of the HCS, according to regime shifts of small pelagics such as anchovy and jack mackerel, under the assumption that E. mucronata is a keystone link.

Resource Management Strategies for the Mobile Web

The success of the Mobile Web is driven by the combination of novel Web-based services with the diffusion of advanced mobile devices that require personalization, location-awareness and content adaptation. The evolutionary trend of the Mobile Web workload places unprecedented strains on the server infrastructure of the content provider at the level of computational and storage capacity, to the extent that the technological improvements at the server and client level may be insufficient to face some resource requirements of the future Mobile Web scenario. This paper presents a twofold contribution. We identify some performance bottlenecks that can limit the performance of future Mobile Web, and we propose and evaluate novel resource management strategies. They aim to address computational requirements through a pre-adaptation of the most popular resources even in the presence of irregular access patterns and short resource lifespan that will characterize the future Mobile Web. We investigate a large space of alternative workload scenarios. Our analysis allows to identify when the proposed resource management strategies are able to satisfy the computational requirements of future Mobile Web, and even some conditions where further research is necessary.

STIMO: STIll and MOving video storyboard for the web scenario

In the current Web scenario a video browsing tool that produces on-the-fly storyboards is more and more a need. Video summary techniques can be helpful but, due to their long processing time, they are usually unsuitable for on-the-fly usage. Therefore, it is common to produce storyboards in advance, penalizing users customization. The lack of customization is more and more critical, as users have different demands and might access the Web with several different networking and device technologies. In this paper we propose STIMO, a summarization technique designed to produce on-the-fly video storyboards. STIMO produces still and moving storyboards and allows advanced users customization (e.g., users can select the storyboard length and the maximum time they are willing to wait to get the storyboard). STIMO is based on a fast clustering algorithm that selects the most representative video contents using HSV frame color distribution. Experimental results show that STIMO produces storyboards with good quality and in a time that makes on-the-fly usage possible.

Early Investigation of New Information Technology Acceptance: A Perceived Risk - Motivation Model

Early investigation of the acceptance of new information technology applications will help to improve the chances of later success. In incipient stages of product deployment, before people develop a full understanding of the aspects of a new technology, users may display particular reasons for or against its use. Accordingly, this study proposes and tests empirically, through structural equation modeling techniques, a perceived risk-motivation model for the early study of new information technology acceptance. The research framework is a Web scenario describing the possible use of wireless text messaging on cell phones to improve user adherence to healthy behavior. While the underlying personal motivation may favor adoption, perceived risks may be an obstacle. This study integrates a multi-faceted perceived risk concept with a motivational model in an unbiased measure of the initial development phase of new information technology, to estimate its acceptance.

Propagation Models for Trust and Distrust in Social Networks

Semantic Web endeavors have mainly focused on issues pertaining to knowledge representation and ontology design. However, besides understanding information metadata stated by subjects, knowing about their credibility becomes equally crucial. Hence, trust and trust metrics, conceived as computational means to evaluate trust relationships between individuals, come into play. Our major contribution to Semantic Web trust management through this work is twofold. First, we introduce a classification scheme for trust metrics along various axes and discuss advantages and drawbacks of existing approaches for Semantic Web scenarios. Hereby, we devise an advocacy for local group trust metrics, guiding us to the second part which presents Appleseed, our novel proposal for local group trust computation. Compelling in its simplicity, Appleseed borrows many ideas from spreading activation models in psychology and relates their concepts to trust evaluation in an intuitive fashion. Moreover, we provide extensions for the Appleseed nucleus that make our trust metric handle distrust statements.

A testbed for performance evaluation of load‐balancing strategies for Web server systems

AbstractTo improve response time of a Web site, one replicates the site on multiple servers. The effectiveness of a replicated server system will depend on how the incoming requests are distributed among replicas. A large number of load‐balancing strategies for Web server systems have been proposed.In this paper we describe a testbed that can be used to evaluate the performance of different load‐balancing strategies. The testbed uses a general architecture which allows different load‐balancing approaches to be supported easily. It emulates a typical World Wide Web scenario and allows variable load generation and performance measurement. We have performed some preliminary experiments to measure the performance of a few policies for load balancing using this testbed. Copyright © 2003 John Wiley & Sons, Ltd.

A Type Inference Algorithm for Secure Ambients

We consider a type discipline for the Ambient Calculus that associates ambients with security levels and constrains them to be traversed by or opened in ambients of higher security clearance only. We present a bottom-up algorithm that, given an untyped process P, computes a minimal set of constraints on security levels such that all actions during runs of P are performed without violating the security level priorities. Such an algorithm appears to be a prerequisite to use type systems to ensure security properties in the web scenario.

Model scenarios for the understanding of molecular recognition

Abstract