3525523
Modelling Trust for System Design Using the i* Strategic Actors Framework
The i*framework was developed to support requirement analysis and high-level design in an agent-oriented system development paradigm. It models intentional dependency relationships among strategic actors and their rationales. As actors depend on each other for goals to be achieved, tasks to be performed, and resources to be furnished, the trust relationships among these actors need to be considered to reason about the opportunities and vulnerabilities these dependencies bring. The concept of softgoal is used to model quality attributes for which there are no a priori, clear-cut criteria for satisfaction, but are judged by actors as being sufficiently met (≪satisficed≫) on a case-by-case basis. In this paper, trustworthiness is treated as a softgoal to be satisficed from the viewpoint of each stakeholder. Contributions to trustworthiness are considered using a qualitative reasoning approach. Examples from the smart card domain are used to illustrate.
464743
Specifying and analyzing early requirements in Tropos
We present a framework that supports the formal verification of early requirements specifications. The framework is based on Formal Tropos, a specification language that adopts primitive concepts for modeling early requirements (such as actor, goal, and strategic dependency), along with a rich temporal specification language. We show how existing formal analysis techniques, and in particular model checking, can be adapted for the automatic verification of Formal Tropos specifications. These techniques have been implemented in a tool, called the T-Tool, that maps Formal Tropos specifications into a language that can be handled by the NuSMV model checker. Finally, we evaluate our methodology on a course-exam management case study. Our experiments show that formal analysis reveals gaps and inconsistencies in early requirements specifications that are by no means trivial to discover without the help of formal analysis tools.
8242993
Designing Web-Based Systems in Social Context: A Goal and Scenario Based Approach
In order to design a better web-based system, a designer would like to have notations to visualize how design experts’ know-how can be applied according to one’s specific social and technology situation. We propose the combined use of a goal-oriented language GRL and a scenarios-oriented notation UCM for representing design knowledge of web-based systems and information systems in general. Goals are used to depict business objectives, functional and non-functional system requirements. Tasks are used in the exploration of alternative technologies and their operationalizations into system constructs. Actors are used to do role-based analysis on social relationships. Scenarios are used to describe elaborated business processes or workflow. The approach is illustrated with an example of designing a web-based training system.
2115447
Security and privacy requirements analysis within a social setting
Security issues for software systems ultimately concern relationships among social actors stakeholders, system users, potential attackers - and the software acting on their behalf. We propose a methodological framework for dealing with security and privacy requirements based on i*, an agent-oriented requirements modeling language. The framework supports a set of analysis techniques. In particular, attacker analysis helps identify potential system abusers and their malicious intents. Dependency vulnerability analysis helps detect vulnerabilities in terms of organizational relationships among stakeholders. Countermeasure analysis supports the dynamic decision-making process of defensive system players in addressing vulnerabilities and threats. Finally, access control analysis bridges the gap between security requirement models and security implementation models. The framework is illustrated with an example involving security and privacy concerns in the design of agent-based health information systems. In addition, we discuss model evaluation techniques, including qualitative goal model analysis and property verification techniques based on model checking.
10661094
Designing information systems in social context: a goal and scenario modelling approach
In order to design a better information system, a designer would like to have notations to visualize how design experts' know-how can be applied according to one's specific social and technology situation. We propose the combined use of a goal-oriented requirements language (GRL) and a scenario-oriented notation Use Case Maps (UCM) for representing design knowledge of information systems. Goal-oriented modelling is used throughout the requirements and design process. In GRL, goals are used to depict business objectives and system requirements, both functional and non-functional. Tasks are used to represent different ways for achieving goals. Means-ends reasoning is used to explore alternative solutions and their operationalizations into implementable system constructs. Social context is modelled in terms of dependency relationships among agents and roles. Scenarios expressed in UCM are used to describe elaborated business processes or workflow. The complementary use of goal-oriented modelling with GRL and scenario modelling with UCM is illustrated with an example of designing a web-based training system.
14598540
Modelling Strategic Actor Relationships to Support Intellectual Property Management
In today's increasingly knowledge-intensive economy, patents and other forms of intellectual property mechanisms are widely used to protect inventions, generate revenue, and build strategic alliances. Techniques from conceptual modelling can be used to analyze the structure of knowledge, highlighting crucial entities and relationships. However, to analyze the strategic significance of particular pieces or bodies of knowledge within an organizational and business context, we need an ontology that captures the social and intentional dimensions of knowledge management. In this paper, we outline the use of the i* strategic actor relationships modelling framework to support IP management. In i*, actors have goals, and know-how and resources for achieving goals. Patents restrict the use of know-how, thus prompting actors to reposition themselves within a network of dependency relationships. Examples from the e-commerce domain are used to illustrate.
12098131
Context Cube: Flexible and Effective Manipulation of Sensed Context Data
In an effort to support the development of context-aware applications that use archived sensor data, we introduce the concept of the Context Cube based on techniques of data warehousing and data mining. Our implementation of the Context Cube provides a system that supports a multi-dimensional model of context data and with tools for accessing, interpreting and aggregating that data by using concept relationships defined within the real context of the application. We define the Context Cube information model, demonstrate functional applications that we have developed with the system, and explore possible applications that may be developed more easily using our tool.
625805
Security vs performance: tradeoffs using a trust framework
We present an architecture of a trust framework that can be used to intelligently tradeoff between security and performance in a SAN file system. The primary idea is to differentiate between various clients in the system based on their trustworthiness and provide them with differing levels of security and performance. Client trustworthiness reflects its expected behavior and is evaluated in an online fashion using a customizable trust model. We also describe the interface of the trust framework with an example block level security solution for an out-of-band virtualization based SAN file system (SAN FS). The proposed framework can be easily extended to provide differential treatment based on data sensitivity, using a configurable parameter of the trust model. This allows associating stringent security requirements for more sensitive data, while trading off security for better performance for less critical data, a situation regularly desired in an enterprise.
8796534
Intelligent OCR Processing
Optical Character Recognition (OCR) has become a highly demanded information transfer technology in recent years. This demand has been driven by the increasing needs for information sharing and office automation, and by the increasing accessibility to largescale, fast, and powerful computer resources. A problem of current OCR technology is that texts produced by the state-of-the-art OCR software contain an unacceptable frequency of errors. This prevents the OCR technology from being efficiently used for vast-volume information transfer or daily office operation applications. To correct these errors in a conventional way requires a significant amount of costly human-machine interaction. In this article, we identify and classify the types and distributions of optical recognition errors. We propose a novel postprocessing strategy, based on machine learning techniques, to correct errors resulted from unrecognized or misrecognized characters during the recognition process. By applying this strategy, the accuracy of recognition can be significantly improved, and the human interaction required can be dramatically reduced. Experimental results indicate that, in a typical environment, about 46% of total errors can be corrected automatically (i.e., without human interference), with an accuracy of 91%.
1558238
Spam-Resilient Web Rankings via Influence Throttling
Web search is one of the most critical applications for managing the massive amount of distributed Web content. Due to the overwhelming reliance on Web search, there is a rise in efforts to manipulate (or spam) Web search engines. In this paper, we develop a spam-resilient ranking model that promotes a source-based view of the Web. One of the most salient features of our spam-resilient ranking algorithm is the concept of influence throttling. We show how to utilize influence throttling to counter Web spam that aims at manipulating link-based ranking systems, especially PageRank-like systems. Through formal analysis and experimental evaluation, we show the effectiveness and robustness of our spam-resilient ranking model in comparison with existing Web algorithms such as PageRank.
13182282
InfoFilter: Supporting quality of service for fresh information delivery
With the explosive growth of the Internet and World Wide Web comes a dramatic increase in the number of users that compete for the shared resources of distributed system environments. Most implementations of application servers and distributed search software do not distinguish among requests to different web pages. This has the implication that the behavior of application servers is quite unpredictable. Applications that require timely delivery of fresh information consequently suffer the most in such competitive environments. This paper presents a model of quality of service (QoS) and the design of a QoS-enabled information delivery system that implements such a QoS model. The goal of this development is two-fold. On one hand, we want to enable users or applications to specify the desired quality of service requirements for their requests so that application-aware QoS adaptation is supported throughout the Web query and search processing. On the other hand, we want to enable an application server to customize how it should respond to external requests by setting priorities among query requests and allocating server resources using adaptive QoS control mechanisms. We introduce the Infopipe approach as the systems support architecture and underlying technology for building a QoS-enabled distributed system for fresh information delivery.