Showing papers by "Brunel University London published in 2002"

An Improved Adaptive Background Mixture Model for Real-time Tracking with Shadow Detection

Abstract: Real-time segmentation of moving regions in image sequences is a fundamental step in many vision systems including automated visual surveillance, human-machine interface, and very low-bandwidth telecommunications A typical method is background subtraction Many background models have been introduced to deal with different problems One of the successful solutions to these problems is to use a multi-colour background model per pixel proposed by Grimson et al [1, 2,3] However, the method suffers from slow learning at the beginning, especially in busy environments In addition, it can not distinguish between moving shadows and moving objects This paper presents a method which improves this adaptive background mixture model By reinvestigating the update equations, we utilise different equations at different phases This allows our system learn faster and more accurately as well as adapts effectively to changing environment A shadow detection scheme is also introduced in this paper It is based on a computational colour space that makes use of our background model A comparison has been made between the two algorithms The results show the speed of learning and the accuracy of the model using our update algorithm over the Grimson et al’s tracker When incorporate with the shadow detection, our method results in far better segmentation than The Thirteenth Conference on Uncertainty in Artificial Intelligence that of Grimson et al

Semisolid metal processing

Abstract: Semisolid metal (SSM) processingis a relatively new technology for metal forming. Different from the conventional metal forming technologies which use either solid metals (solid state processing) or liquid metals (casting) as starting materials, SSM processing deals with semisolid slurries, in which non-dendritic solid particles are dispersed in a liquid matrix. Semisolid metal slurries exhibit distinctive rheological characteristics: the steady state behaviour is pseudoplastic (or shear thinning), while the transient state behaviour is thixotropic. All the currently available technologies for SSM processing have been developed based on those unique rheological properties, which in turn originate from their non-dendritic microstructures. Year 2001 marks the 30th anniversary of the concept of SSM processing. Today, SSM processing has established itself as a scientifically sound and commercially viable technology for production of metallic components with high integrity, improved mechanical properti...

The BABAR detector

Abstract: BABAR, the detector for the SLAC PEP-II asymmetric e+e- B Factory operating at the upsilon 4S resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagentic showers from electrons and photons are detected in an array of CsI crystals located just inside the solenoidal coil of a superconducting magnet. Muons and neutral hadrons are identified by arrays of resistive plate chambers inserted into gaps in the steel flux return of the magnet. Charged hadrons are identified by dE/dx measurements in the tracking detectors and in a ring-imaging Cherenkov detector surrounding the drift chamber. The trigger, data acquisition and data-monitoring systems, VME- and network-based, are controlled by custom-designed online software. Details of the layout and performance of the detector components and their associated electronics and software are presented.

The key to success in innovation part i: the art of interessement

Abstract: We all know of innovations which either made their creators a fortune or which led to their downfall. It is easy to retrospectively explain success as a stroke of genius or failure as a blatant mistake. Easy in retrospect…but what about innovation in the making? How does the innovator navigate the pitfalls which threaten him?

Altered Sexual Maturation and Gamete Production in Wild Roach (Rutilus rutilus) Living in Rivers That Receive Treated Sewage Effluents

Abstract: Disruption in gonadal development of wild roach living in U.K. rivers receiving large volumes of treated sewage effluent is manifest in a variety of ways, ranging from malformation of the germ cells and/or reproductive ducts to altered gamete production. Intersex fish were also found to have an altered endocrine status and an elevated concentration of plasma vitellogenin. Gonadal growth was inhibited only in severely intersex fish, whereas progression of spermatogenesis was delayed in a large proportion of all intersex and exposed male fish. In contrast to the effects observed in the intersex and exposed male fish, the maturation of ovaries in female fish inhabiting effluent-contaminated rivers appeared to be less obviously affected, although a higher incidence of oocyte atresia was found in the effluent-exposed fish compared with the reference fish. A positive correlation was found between the proportion of female tissue in the gonads of intersex fish and their plasma vitellogenin concentration, suggesting that vitellogenin can be an indicator for the level of gonadal disruption in intersex roach. The estradiol-17β concentration in intersex fish was intermediate between the concentration found in males and females, and the plasma testosterone was between 2- and 3-fold higher in intersex fish compared with male fish. These data suggest a link between altered endocrine status in intersex and female fish and gonadal disruption. Spermiation was also affected in roach living in effluent-impacted rivers: a lower proportion of fish were found releasing sperm, and in those intersex fish that were spermiating, a reduced milt volume and a reduced sperm density were found. All intersex fish had malformations of the reproductive duct(s), and in severely affected fish, the ducts were occluded, thus preventing release of gametes. In view of the widespread occurrence of intersexuality in wild fish populations in rivers throughout the United Kingdom, assessment of the reproductive capabilities of these intersex roach is clearly needed to understand the impact of this phenomenon on roach fertility.

Wild Intersex Roach (Rutilus rutilus) Have Reduced Fertility

Abstract: Endocrine-disrupting chemicals, known to be present in the environment, have great potential for interfering with reproductive health in wildlife and humans. There is, however, little direct evidence that endocrine disruption has adversely affected fertility in any organism. In freshwater and estuarine fish species, for example, although a widespread incidence of intersex has been reported, it is not yet known if intersexuality influences reproductive success. The purpose of this study was, therefore, to determine gamete quality in wild intersex roach (Rutilus rutilus) by assessing sperm characteristics, fertilization success, and ability to produce viable offspring. The results clearly demonstrate that gamete production is reduced in intersex roach. A significantly lower proportion of moderately or severely feminized fish (17.4% and 33.3%, respectively) were able to release milt compared with normal male fish from contaminated rivers (in which 97.6% of the males were able to release milt), reference male fish (97.7%), or less severely feminized intersex fish (experiment 1: 85.8%, experiment 2: 97%). Intersex fish that did produce milt produced up to 50% less (in terms of volume per gram of testis weight) than did histologically normal male fish. Moreover, sperm motility (percentage of motile sperm and curvilinear velocity) and the ability of sperm to successfully fertilize eggs and produce viable offspring were all reduced in intersex fish compared with normal male fish. Male gamete quality (assessed using sperm motility, sperm density, and fertilization success) was negatively correlated with the degree of feminization in intersex fish (r = -0.603; P < 0.001) and was markedly reduced in severely feminized intersex fish by as much as 50% in terms of motility and 75% in terms of fertilization success when compared with either less severely feminized intersex fish or unaffected male fish. This is the first evidence documenting a relationship between the morphological effects (e.g., intersex) of endocrine disruption and the reproductive capabilities of any wild vertebrate. The results suggest that mixtures of endocrine-disrupting substances discharged into the aquatic environment could pose a threat to male reproductive health.

Cultural differences in the online behavior of consumers

Abstract: Understanding how different cultures use the Net---as well as perceive the same Web sites---can translate to truly global e-commerce.

Condition monitoring techniques for electrical equipment-a literature survey

Abstract: Increasing interest has been seen in condition monitoring (CM) techniques for electrical equipment, mainly including transformer, generator, and induction motor in power plants, because CM has the potential to reduce operating costs, enhance the reliability of operation, and improve power supply and service to customers. Literature is accumulated on developing intelligent CM systems with advanced practicability, sensitivity, reliability, and automation. A literature survey is felt necessary with an aim to reflect the state-of-the-art development in this important area. After introducing the concepts and functions of CM, this paper describes the popular monitoring methods for and research status of CM on transformers, generators, and induction motors, respectively. The paper also points out the potential benefits through the utilization of advanced signal processing and artificial intelligence techniques in developing novel CM schemes.

Stem Cells, Tissue Cultures and the Production of Biovalue:

Abstract: This article examines some of the social and philosophical implications of stem cell technologies. Stem cell technologies promise to transform the way that healthy tissues for transplant are sourced and circulated; from a social economy in which citizens donate whole organs to others, to one in which embryos are a major source of therapeutic tissues. This article considers the transformations in concepts of health, bodily relationships and social indebtedness that such a shift might entail. Using the concept of biovalue, this article describes the ways embryos are biologically engineered to act as tissue sources, and considers the relationship between biovalue, health and capital value. It discusses the effects stem cell technologies may have on concepts of the healthy body, particularly on the temporality of ageing, and on understandings of the human more generally.

Malleable attentional resources theory: A new explanation for the effects of mental underload on performance

Abstract: This paper proposes a new theory to account for the effects of underload on performance. Malleable attentional resources theory posits that attentional capacity can change size in response to changes in task demands. As such, the performance decrements associated with mental underload can be explained by a lack of appropriate attentional resources. These proposals were explored in a driving simulator experiment. Vehicle automation was manipulated at 4 levels, and mental workload was assessed with a secondary task. Eye movements were also recorded to determine whether attentional capacity varied with mental workload. The results showed a clear decrease in mental workload associated with some levels of automation. Most striking, though, were the results derived from the eye movement recordings, which demonstrated that attentional capacity varies directly with level of mental workload. These data fully supported the predictions of the new theory. Malleable attentional resources theory suggests that future vehicle designers should employ their technology in driver support systems rather than in automation to replace the driver. The implications of this theory are discussed with regard to capacity models of attention as well as to the design of future vehicle systems.

Cognitive styles and hypermedia navigation: development of a learning model

Abstract: There has been an increased growth in the use of hypermedia to deliver learning and teaching material. However, much remains to be learned about how different learners perceive such systems. Therefore, it is essential to build robust learning models to illustrate how hypermedia features are experienced by different learners. Research into individual differences suggests cognitive styles have a significant effect on student learning in hypermedia systems. In particular, Witkin's Field Dependence has been extensively examined in previous studies. This article reviews the published findings from empirical studies of hypermedia learning. Specifically, the review classifies the research into five themes: nonlinear learning, learner control, navigation in hyperspace, matching and mismatching, and learning effectiveness. A learning model, developed from an analysis of findings of the previous studies, is presented. Finally, implications for the design of hypermedia learning systems are discussed.

User Involvement in Research and Evaluation: Liberation or Regulation?

Abstract: This article explores the progressive and regressive potential of ‘user involvement’ in research and evaluation, with particular reference to social policy. There is growing political and research interest in user involvement. This article critically explores key different approaches to user involvement in research and relates them to consumerist and democratic models of involvement in policy and practice, management and development. The article highlights the need to approach user involvement in research critically and systematically, taking account of the diversity of approaches that have developed and to take forward user involvement in research in equal association with service user organisations and movements.

Developing a frame of reference for ex-ante IT/IS investment evaluation

Abstract: Investment appraisal techniques are an integral part of many traditional capital budgeting processes. However, the adoption of Information Systems (IS) and the development of resulting infr...

The key to success in innovation part ii: the art of choosing good spokespersons

Abstract: “Solve the technical problems first”, we often hear, “then we’ll deal with the market”. The real history of innovations does not generally follow this simple schema; it is made of adaptations, series of trial and error and countless negotiations between numerous social actors. A genuine combat from which conquerors who know how to choose good representatives emerge.

`Natural' and `contrived' data: a sustainable distinction?:

Abstract: One of the most consistent and (for some) troubling findings of mainstream social scientific research, is that the context in which a research project takes place has a significant effect on the behaviour of respondents and the overall quality of the data (Banyard and Hunt, 2000; Schuman and Presser, 1996). Researchers working within both positivist and interpretative paradigms, for example, worry that their data collection techniques are not wholly neutral or objective instruments, and that there are numerous potential sources of ‘bias’ (Hammersley and Gomm, 1997) which may lead to invalid and erroneous results (‘researcher effects’, ‘reactivity’, ‘context effects’, ‘observer effects’, and so on). Because they represent a source of error, these effects are treated as problems which must be overcome by improving the research instrument or by taking ‘proper methodological precautions’ (p. 11). Books on interview methodology, for example, often advise researchers to minimize the ‘intrusive’ effects of a variety of interactional and contextual features. Some frequently recommended ‘techniques’ include taking time to build up a rapport with respondents, allowing for acclimatization periods (such that the researcher and his or her tools can ‘blend’ with the setting), dressing in a way that is not intimidating, learning about techniques to broach sensitive topics, being non-directive, and so on (see Judd et al., 1991). Thus, the primary aim is to eliminate extraneous, researchinduced ‘contaminants’ and uncover some more ‘pristine’ reality. One of the distinguishing features of discursive and conversation analytic (CA) approaches, by contrast, is their emphasis on the action orientation of talk, and the local, or ‘endogenous’ production of context (Potter and Wetherell, 1987; Schegloff, 1997a; Hutchby and Wooffitt, 1998). Since these approaches treat respondents, not as passive containers of knowledge, but as active participants within the research process who construct, rather than report on reality, ‘bias’ is regarded as both unavoidable and pervasive. Research contexts are thoroughly social, interactional occasions, and it is for this reason that, as Holstein D E B AT E 511

Do multidisciplinary integrated care pathways improve interprofessional collaboration

Abstract: This paper reports on the evaluation stage of an action research project on interprofessional collaboration in discharge planning Findings from interviews with health care professionals working in the acute sector had revealed concerns about discharge planning and multidisciplinary teamwork In the United Kingdom the National Health Service (NHS) Plan has reinforced the need for an integrated approach to health care Effective health care integration requires effective communication, teamwork and the commitment to deliver integrated care Integrated documentation is a key strategy for enhancing interprofessional collaboration and reducing the isolation of professionals, and has been successfully implemented in a range of health care settings Presented with the concerns about the collaborative process in discharge planning, an action research strategy was chosen to bring about change in an orthopaedic ward in one London teaching hospital This paper will evaluate the implementation of an integrated care pathway with fractured neck of femurs in one London teaching hospital Care pathways facilitate the management of defined patient groups using interdisciplinary plans of care The emphasis will be on understanding whether integrated care pathways enhance and develop interprofessional collaboration and enable effective information access and flow across the professions and the organization The criteria for evaluation, forming the hypotheses of the study, were that interprofessional nonverbal and verbal communication would be enhanced and that interprofesisonal collaboration would increase Methods of evaluation used were: (i) stakeholder interviews, (ii) interprofessional audit and (iii) analysis of the variances from the integrated care pathway The evaluation revealed that although integrated care pathways led to improved outcomes for the health care trust there was little evidence to suggest that interprofessional relationships and communication were enhanced Furthermore, key factors in discharge delays appeared to be organizational rather than professional

Effective Communication in Requirements Elicitation: A Comparison of Methodologies

Abstract: The elicitation or communication of user requirements comprises an early and critical but highly error-prone stage in system development. Socially oriented methodologies provide more support for user involvement in design than the rigidity of more traditional methods, facilitating the degree of user---designer communication and the `capture' of requirements. A more emergent and collaborative view of requirements elicitation and communication is required to encompass the user, contextual and organisational factors. From this accompanying literature in communication issues in requirements elicitation, a four-dimensional framework is outlined and used to appraise comparatively four different methodologies seeking to promote a closer working relationship between users and designers. The facilitation of communication between users and designers is subject to discussion of the ways in which communicative activities can be `optimised' for successful requirements gathering, by making recommendations based on the four dimensions to provide fruitful considerations for system designers.

Effects of decision aids for menorrhagia on treatment choices, health outcomes, and costs: a randomized controlled trial.

Abstract: ContextDecision aids can increase patient involvement in treatment decision making. However, questions remain regarding their effects and cost implications.ObjectiveTo evaluate the effects of information, with and without a structured preference elicitation interview, on treatment choices, health outcomes, and costs.Design, Setting, and ParticipantsA randomized controlled trial with 2 years of follow-up. Between October 1996 and February 1998, 894 women with uncomplicated menorrhagia were recruited from 6 hospitals in southwest England. Women were randomized to the control group, information alone group (information), or information plus interview group (interview).InterventionsWomen in both intervention groups were sent an information pack (a booklet and complementary videotape) 6 weeks before their specialist consultation. Immediately before their consultation, women in the interview group underwent structured interview, to clarify and elicit their preferences.Main Outcome MeasuresSelf-reported health status was the main outcome; secondary outcomes included treatments received and costs. Cost analyses adopted a UK health service (payer) perspective, and were based on patient-reported resource use data and are reported in 1999-2000 US dollars.ResultsThe interventions had no consistent effect on health status. Hysterectomy rates were lower for women in the interview group (38%) (adjusted odds ratio [OR], 0.60; 95% confidence interval [CI], 0.38-0.96) than in the control group (48%) and women who received the information alone (48%) (adjusted OR, 0.52; 95% CI, 0.33-0.82). The interview group had lower mean costs ($1566) than the control group ($2751) (mean difference, $1184; 95% CI, $684-$2110) and the information group $2026 (mean difference, $461; 95% CI, $236-$696).ConclusionsNeither intervention had an effect on health status. Providing women with information alone did not affect treatment choices; however, the addition of an interview to clarify values and elicit preferences had a significant effect on women's management and resulted in reduced costs.

Towards an integrated approach to knowledge management: hard, soft and abstract issues

Abstract: Companies are often unaware of the potential value of corporate information and extent of data held in their systems. It is increasingly argued that analysis of such data and information can be transformed into knowledge that in turn can be used to gain business benefits such as a competitive advantage, minimization of costs, improved quality, responsiveness, or improved service to customers. This paper investigates the benefits of a systematic and interdisciplinary approach to research in knowledge management, particularly in investigating technical (hard), organizational (soft), as well as philosophical (abstract) aspects of the concept. It describes in detail the framework used in research undertaken by the Centre for Knowledge and Business Process Management at Brunel University. We argue that this framework is useful to researchers and practitioners alike as it contributes to a systematic and more effective knowledge management approach.

Performance and analysis of a 4-stroke multi-cylinder gasoline engine with CAI combustion

Abstract: Copyright © 2002 SAE International. This paper is posted on this site with permission from SAE International. Further use of this paper is not permitted without permission from SAE

The Role of Intermediaries in Electronic Marketplaces: Developing a Contingency Model

Abstract: . Early research in electronic markets seemed to suggest that e- commerce transactions would result in decreased costs for buyers and sellers alike, and would therefore ultimately lead to the elimination of intermediaries from electronic value chains. However, a careful analysis of the structure and functions of electronic marketplaces reveals a different picture. Intermediaries provide many value-adding functions that cannot be easily substituted or ‘internalized’ through direct supplier–buyer dealings, and hence mediating parties may continue to play a significant role in the e-commerce world. In this paper we provide an analysis of the potential roles of intermediaries in electronic markets and we articulate a number of hypotheses for the future of intermediation in such markets. Three main scenarios are discussed: the disintermediation scenario, in which market dynamics will favour direct buyer–seller transactions; the reintermediation scenario, in which traditional intermediaries will be forced to differentiate themselves and re-emerge in the electronic marketplace; and the cybermediation scenario, in which wholly new markets for intermediaries will be created. The analysis suggests that the likelihood of each scenario dominating a given market is primarily dependent on the exact functions that intermediaries play in each case. A detailed discussion of such functions is presented in the paper, together with an analysis of likely outcomes in the form of a contingency model for intermediation in electronic markets.

Changes in estrogenic and androgenic activities at different stages of treatment in wastewater treatment works

Abstract: Estrogenic and androgenic activities of wastewater were determined during treatment in five wastewater treatment works (WWTWs) in the Untied Kingdom. With one exception, both estrogenic and androgenic activities decreased markedly as wastewater progressed through the plants; removal rates were generally 70% or higher, sometimes reaching 100%. Most of the reduction in activity occurred during secondary (biological) treatment. In both influents and effluents, estrogenic and androgenic activities were appreciably lower in samples collected in August, when the amount of rain had been substantial, compared with samples collected in April and May. Most final effluents contained very low (or nondetectable) estrogenic activity (undetectable to 13 ng/L of estradiol equivalents) and androgenic activity (undetectable to 143 ng/L of dihydrotestosterone [DHT] equivalents), although one (from a WWTW that had only primary treatment) contained relatively high activities (40 ng/L of estradiol equivalents; 4,033 ng/L of DHT equivalents). The type of treatment available at the various WWTWs also affected the activity of the final effluent. The biological significance of these results will depend upon which chemicals contribute to the estrogenic and androgenic activities, because of widely different potencies of different estrogenic chemicals, and on the degree of dilution of the effluents in their receiving waters.

Power flow control approach to power systems with embedded FACTS devices

Abstract: This paper focuses on developing an approach to steady-state power flow control of flexible AC transmission systems (FACTS) device-equipped power systems. Based on a power-injection model of FACTS devices and an optimal power flow model, a novel versatile power flow control approach is formulated, which is capable of implementing power flow control incorporating any FACTS device flexibly. Different from existing FACTS device control approaches, the active and (or) reactive power injections are taken as independent control variables. Therefore, using this method, Jacobian matrix need not be changed, although various FACTS devices possess different physical models and different control parameters. Furthermore, it enables the integration of FACTS devices into the existing power system analysis and control programs efficiently. Physical limits of the FACTS devices are also considered in the model. Numerical results on a reduced practical system and a 1500-bus practical system with various FACTS devices are presented to illustrate the vigorousness of the proposed approach.

Attention and automation: New perspectives on mental underload and performance

Abstract: There is considerable evidence in the ergonomics literature that automation can significantly reduce operator mental workload. Furthermore, reducing mental workload is not necessarily a good thing, particularly in cases where the level is already manageable. This raises the issue of mental underload, which can be at least as detrimental to performance as overload. However, although it is widely recognized that mental underload is detrimental to performance, there are very few attempts to explain why this may be the case. It is argued in this paper that, until the need for a human operator is completely eliminated, automation has psychological implications relevant in both theoretical and applied domains. The present paper reviews theories of attention, as well as the literature on mental workload and automation, to synthesize a new explanation for the effects of mental underload on performance. Malleable attentional resources theory proposes that attentional capacity shrinks to accommodate reductions in m...

Towards new forms of knowledge communication: the adaptive dimension of a web-based learning environment

Abstract: Adaptive Educational Hypermedia Systems aim to increase the functionality of hypermedia by making it personalised to individual learners. The adaptive dimension of these systems mainly supports knowledge communication between the system and the learner by adapting the content or the appearance of hypermedia to the knowledge level, goals and other characteristics of each learner. The main objectives are to protect learners from cognitive overload and disorientation by supporting them to find the most relevant content and path in the hyperspace. In the approach presented in this paper, learners’ knowledge level and individual traits are used as valuable information to represent learners’ current state and personalise the educational system accordingly, in order to facilitate learners to achieve their personal learning goals and objectives. Learners’ knowledge level is approached through a qualitative model of the level of performance that learners exhibit with respect to the concepts they study and is used to adapt the lesson contents and the navigation support. Learners’ individual traits and especially their learning style represent the way learners perceive and process information, and are exploited to adapt the presentation of the educational material of a lesson. The proposed approach has been implemented through various adaptation technologies and incorporated into a prototype hypermedia system. Finally, a pilot study has been conducted to investigate system’s educational effectiveness. # 2002 Elsevier Science Ltd. All rights reserved.