Sensor scheduling in electronic support using Markov chains

In electronic support, receivers must maintain surveillance over the very wide portion of the electromagnetic spectrum in which threat emitters operate. A common approach is to use a receiver with a relatively narrow bandwidth that sweeps its centre frequency over the threat bandwidth to search for emitters. The sequence and timing of changes in the centre frequency constitute a search strategy. The search can be expedited, if there is intelligence about the operational parameters of the emitters that are likely to be found. However, it can happen that the intelligence is deficient, untrustworthy or absent. In this case, what is the best search strategy to use? A random search strategy based on a continuous-time Markov chain (CTMC) is proposed. When the search is conducted for emitters with a periodic scan, it is shown that there is an optimal configuration for the CTMC. It is optimal in the sense that the expected time to intercept an emitter approaches linearity most quickly with respect to the emitter's scan period. A fast and smooth approach to linearity is important, as other strategies can exhibit considerable and abrupt variations in the intercept time as a function of scan period. In theory and numerical examples, the optimum CTMC strategy is compared with other strategies to demonstrate its superior properties.

Information systems maturity in e-business organizations

E-Business Information Systems (eBIS) are Information Systems (IS) that support organizations to realize their e-Business strategy resulting in various benefits. Therefore those systems strongly focus on fulfilment of the e-business requirements. In order to realise the expected benefits, organizations need to turn to their eBIS and measure the maturity of those systems. In doing so, they need to identify the status of those systems with regards to their suitability to support the e-Business strategy, while also identifying required IS improvements. In our research we aim to develop a maturity model, particularly dedicated to the area of e-Business Information Systems, which can be used easily and objectively to measure of the current maturity of any Information System that supports e-Business. This research-in-progress paper presents initial results of our research.

Developing a meta model for the Bunge-Wand-Weber ontological constructs

At the core of the analysis task in the development process is information systems requirements modelling, Modelling of requirements has been occurring for many years and the techniques used have progressed from flowcharting through data flow diagrams and entity-relationship diagrams to object-oriented schemas today. Unfortunately, researchers have been able to give little theoretical guidance only to practitioners on which techniques to use and when. In an attempt to address this situation, Wand and Weber have developed a series of models based on the ontological theory of Mario Bunge-the Bunge-Wand-Weber (BWW) models. Two particular criticisms of the models have persisted however-the understandability of the constructs in the BWW models and the difficulty in applying the models to a modelling technique. This paper addresses these issues by presenting a meta model of the BWW constructs using a meta language that is familiar to many IS professionals, more specific than plain English text, but easier to understand than the set-theoretic language of the original BWW models. Such a meta model also facilitates the application of the BWW theory to other modelling techniques that have similar meta models defined. Moreover, this approach supports the identification of patterns of constructs that might be common across meta models for modelling techniques. Such findings are useful in extending and refining the BWW theory. (C) 2002 Elsevier Science Ltd. All rights reserved.

Ontological evaluation of enterprise systems interoperability using ebXML

Enterprise systems interoperability (ESI) is an important topic for business currently. This situation is evidenced, at least in part, by the number and extent of potential candidate protocols for such process interoperation, viz., ebXML, BPML, BPEL, and WSCI. Wide-ranging support for each of these candidate standards already exists. However, despite broad acceptance, a sound theoretical evaluation of these approaches has not yet been provided. We use the Bunge-Wand-Weber (BWW) models, in particular, the representation model, to provide the basis for such a theoretical evaluation. We, and other researchers, have shown the usefulness of the representation model for analyzing, evaluating, and engineering techniques in the areas of traditional and structured systems analysis, object-oriented modeling, and process modeling. In this work, we address the question, what are the potential semantic weaknesses of using ebXML alone for process interoperation between enterprise systems? We find that users will lack important implementation information because of representational deficiencies; due to ontological redundancy, the complexity of the specification is unnecessarily increased; and, users of the specification will have to bring in extra-model knowledge to understand constructs in the specification due to instances of ontological excess.

An overview of the MPEG-7 description definition language (DDL)

This paper presents an overview of the MPEG-7 Description Definition Language (DDL). The DDL provides the syntactic rules for creating, combining, extending and refining MPEG-7 Descriptors (Ds) and Description Schemes (DSs), In the interests of interoperability, the W3C's XML Schema language, with the addition of certain MPEG-7-specific extensions, has been chosen as the DDL. This paper describes the background to this decision and using examples, provides an overview of the core XML, schema features used within MPEG-7 and the extensions made in order to satisfy the MPEG-7 DDL requirements.

Using a cartographic modeling language to manipulate spectral satellite imagery

Land related information about the Earth's surface is commonIJ found in two forms: (1) map infornlation and (2) satellite image da ta. Satellite imagery provides a good visual picture of what is on the ground but complex image processing is required to interpret features in an image scene. Increasingly, methods are being sought to integrate the knowledge embodied in mop information into the interpretation task, or, alternatively, to bypass interpretation and perform biophysical modeling directly on derived data sources. A cartographic modeling language, as a generic map analysis package, is suggested as a means to integrate geographical knowledge and imagery in a process-oriented view of the Earth. Specialized cartographic models may be developed by users, which incorporate mapping information in performing land classification. In addition, a cartographic modeling language may be enhanced with operators suited to processing remotely sensed imagery. We demonstrate the usefulness of a cartographic modeling language for pre-processing satellite imagery, and define two nerv cartographic operators that evaluate image neighborhoods as post-processing operations to interpret thematic map values. The language and operators are demonstrated with an example image classification task.

Hypercapitalism: Language, new media and social perceptions of value

Using examples from contempoary policy and business discourses, and exemplary historical texts dealing with the notion of value, I put forward an argument as to why a critical scholarship that draws on media history, language analysis, philosophy and political economy is necessary to understand the dynamics of what is being called 'the global knowledge economy'. I argue that the social changes associated with new modes of value determination are closely associated with new media form.

A funny thing happened on the way to the forum: Electronic discussion and foreign language learning

Amongst the opportunities for cross-cultural contact created by the burgeoning use of the Internet are those provided by electronic discussion lists. This study looks at what happens when language students venture out of the classroom (virtual or otherwise) to participate in on-line discussion groups with native speakers. Responses to messages and commentary by moderators and other participants on the (in) appropriateness of contributions allow us to determine what constitutes successful participation and to make suggestions regarding effective teaching strategies for this medium. A case study examines the threads started by four anglophone students of French when they post messages to a forum on the Web site of the French newspaper Le Monde. Investigation of these examples points to the ways in which electronic discussion inflects and is inflected by cultural and generic expectations. We suggest that successful participation on Internet fora depends on awareness of such cultural and generic mores and an ability to work within and/or with them. Teachers therefore need to find ways in which students can be sensitized to such issues so that their participation in such electronic discussion is no longer seen as linguistic training, but as engagement with a cultural practice.

Evaluating the role of speech-language pathology with patients with communication disability in the acute hospital setting using the ICF

The practice of speech-language pathology in the acute care hospital setting has changed dramatically over the last 20 years. Speech-language pathologists now routinely assess and manage patients with dysphagia as well as patients with acquired communication disorders. In practice, clinicians have tended to direct their limited resources toward the assessment and management of patients with dysphagia before addressing the needs of patients with acquired communication disorders. This practice has resulted in a decline in speech-language pathology services for patients with communication disorders and has led some clinicians to question the role of the speech-language pathologist in the acute care hospital setting. This article continues this discussion by evaluating the role of the speech-language pathologist in the acute care hospital setting within the context of the World Health Organization's (WHO) International Classification of Functioning, Disability and Health (ICF; WHO, 2001). It argues that by adopting the ICF, speech-language pathologists have a sound rationale for broadening their role to identify the communication needs of all hospital inpatients who experience communication difficulties in the acute care hospital setting.

Diversification and extensible networks: The strategies of Chinese businesses in Australia

The paper reports on a study of 28 ethnic Chinese businesses in Brisbane, Adelaide, and Perth, carried out in 2000 and 2001. It focuses on their strategies of vertical, horizontal, and unrelated diversification often combining different activities, products, and markets at the same time. It demonstrates how these practices are socially embedded in their preference for using personal networks. Non-related diversification, in particular, promotes and is facilitated by using weak ties that serve as bridges, leading into new networks (Granovetter, 1973). This can create links to Chinese of different national and dialect origins and to those of other ethnicities. It is suggested that open networks and diversification mutually interact to support each other and may have evolved in tandem from earlier, more closed and niche bound business cultures and practices.

Speaking for others: The pros and cons of group advocates using collective language

We examined how rhetorical style affects evaluations of group advocates, and how these evaluations are moderated by group identification. University students were given a letter to the editor defending student welfare. The argument was either constructed using personal language ('I believe') or collective language ('we believe'). Furthermore, the letter was either attributed to an official advocate (president of the student union) or an unofficial advocate (a rank-and-file member of the student body). Consistent with the social identity perspective, participants who showed strong identification as a university student thought that the group would feel better represented by official advocates using collective rather than personal language. Low identifiers, however, did not rate the rhetorical styles differently on representativeness. Furthermore, low identifiers (but not high identifiers) rated official advocates as more likable and more effective when they used personal rather than collective language. The discussion focuses on the conflict low identifiers might feel between (a) needing to homogenize with other group members in order to maximize the influence and political effectiveness of their message at the collective level, and (b) protecting themselves against categorization threat.