Search results for "Computer Networks and Communication"
showing 10 items of 834 documents
The effectiveness of office information systems: a social action perspective
1991
. The purpose of this paper is to show that a number of basic issues have not been adequately addressed in existing office information systems research. Prominent among these are the nature and role of offices, the goals of office information systems development, and the nature of its organizational and managerial consequences. It is proposed that office information systems should be analysed as social action systems the behaviour of which is strongly affected by socially determined forces and constraints such as the behaviour-channelling influences of authority, norms, customs, habits and precedence. Four types of social action are discussed: instrumental, strategic, communicative and disc…
Noise-tolerant efficient inductive synthesis of regular expressions from good examples
1997
We present an almost linear time method of inductive synthesis restoring simple regular expressions from one representative (good) example. In particular, we consider synthesis of expressions of star-height one, where we allow one union operation under each iteration, and synthesis of expressions without union operations from examples that may contain mistakes. In both cases we provide sufficient conditions defining precisely the class of target expressions and the notion of good examples under which the synthesis algorithm works correctly, and present the proof of correctness. In the case of expressions with unions the proof is based on novel results in the combinatorics of words. A genera…
On the chromatic number of disk graphs
1998
Colorings of disk graphs arise in the study of the frequency-assignment problem in broadcast networks. Motivated by the observations that the chromatic number of graphs modeling real networks hardly exceeds their clique number, we examine the related properties of the unit disk (UD) graphs and their different generalizations. For all these graphs including the most general class of the double disk (DD) graphs, it is shown that X(G) ≤ c.ω(G) for a constant c. Several coloring algorithms are analyzed for disk graphs, aiming to improve the bounds on X(G). We find that their worst-case performance expressed in the number of used colors is indeed reached in some instances.
Using Cloud Computing to Implement a Security Overlay Network
2012
This article proposes and analyzes a general cloud-based security overlay network that can be used as a transparent overlay network to provide services such as intrusion detection systems, antivirus and antispam software, and distributed denial-of-service prevention. The authors analyze each of these in-cloud security services in terms of resiliency, effectiveness, performance, flexibility, control, and cost.
Comparative analysis of architectures for monitoring cloud computing infrastructures
2015
The lack of control over the cloud resources is one of the main disadvantages associated to cloud computing. The design of efficient architectures for monitoring such resources can help to overcome this problem. This contribution describes a complete set of architectures for monitoring cloud computing infrastructures, and provides a taxonomy of them. The architectures are described in detail, compared among them, and analysed in terms of performance, scalability, usage of resources, and security capabilities. The architectures have been implemented in real world settings and empirically validated against a real cloud computing infrastructure based on OpenStack. More than 1000 virtual machin…
Combining social media affordances for organising collective action
2020
Swarming Models for Facilitating Collaborative Decisions
2010
The paper highlights the computational power of swarming models (i.e., stigmergic mechanisms) to build collaborative support systems for complex cognitive tasks such as facilitation of group decision processes (GDP) in e-meetings. Unlike traditional approaches that minimize the cognitive complexity by incorporating the facilitation knowledge into the system, stigmergic coordination mechanisms minimize the complexity by providing the system with emergent functionalities that are shaped by the environment itself through the possibility to structure it in terms of high-level cognitive artefacts. This is illustrated by conducting a socio-simulation experiment for an envisioned collaborative sof…
XPL the Extensible Presentation Language
2009
The last decade has witnessed a growing interest in the development of web interfaces enabling both multiple ways to access contents and, at the same time, fruition by multiple modalities of interaction (point-and-click, contents reading, voice commands, gestures, etc.). In this paper we describe a framework aimed at streamlining the design process of multi-channel, multimodal interfaces enabling full reuse of software components. This framework is called the eXtensible Presentation architecture and Language (XPL), a presentation language based on design pattern paradigm that keeps separated the presentation layer from the underlying programming logic. The language supplies a methodology to…
Mobile social networking in theory and practice
2008
Mobile social networks have gained the attention of the media, academy and mobile market. Despite of the robust tradition of network and community studies, mobile social networks are often addressed improperly. This paper presents a theoretical framework to study mobile social networking and examines the design implications of results of an exploratory study conducted with a group of 18 young adults in Finland. The findings of this study indicate that the quality of mobile applications offering social networking could be greatly increased by integrating the knowledge of two traditions that so far developed in parallel, namely the mathematical as well as social approaches to social networks.
Learning with belief levels
2008
AbstractWe study learning of predicate logics formulas from “elementary facts,” i.e. from the values of the predicates in the given model. Several models of learning are considered, but most of our attention is paid to learning with belief levels. We propose an axiom system which describes what we consider to be a human scientist's natural behavior when trying to explore these elementary facts. It is proved that no such system can be complete. However we believe that our axiom system is “practically” complete. Theorems presented in the paper in some sense confirm our hypothesis.