Showing papers by "City University London published in 2000"

A probabilistic model of information retrieval: development and comparative experiments

Abstract: The paper combines a comprehensive account of the probabilistic model of retrieval with new systematic experiments on TREC Programme material. It presents the model from its foundations through its logical development to cover more aspects of retrieval data and a wider range of system functions. Each step in the argument is matched by comparative retrieval tests, to provide a single coherent account of a major line of research. The experiments demonstrate, for a large test collection, that the probabilistic model is eAective and robust, and that it responds appropriately, with major improvements in performance, to key features of retrieval situations. Part 1 covers the foundations and the model development for document collection and relevance data, along with the test apparatus. Part 2 covers the further development and elaboration of the model, with extensive testing, and briefly considers other environment conditions and tasks, model training, concluding with comparisons with other approaches and an overall assessment. Data and results tables for both parts are given in Part 1. Key results are summarised in Part 2. 7 2000 Elsevier Science Ltd. All rights reserved.

Prevalence and natural history of primary speech and language delay: findings from a systematic review of the literature.

Abstract: The prevalence and the natural history of primary speech and language delays were two of four domains covered in a systematic review of the literature related to screening for speech and language delay carried out for the NHS in the UK. The structure and process of the full literature review is introduced and criteria for inclusion in the two domains are specified. The resulting data set gave 16 prevalence estimates generated from 21 publications and 12 natural history studies generated from 18 publications. Results are summarized for six subdivisions of primary speech and language delays: (1) speech and/or language, (2) language only, (3) speech only, (4) expression with comprehension, (5) expression only and (6) comprehension only. Combination of the data suggests that both concurrent and predictive case definition can be problematic. Prediction improves if language is taken independently of speech and if expressive and receptive language are taken together. The results are discussed in terms of the need to develop a model of prevalence based on risk of subsequent difficulties.

Stock Prices and Exchange Rate Dynamics

Abstract: We study the long-run and short-run dynamics between stock prices and exchange rates and the channels through which exogenous shocks impact on these markets. We apply the analysis to a group of Pacific Basin countries and examine whether foreign exchange controls and the Asian financial crisis of mid 1997 affected the links between the markets. The evidence shows that the US stock market acts as a conduit through which the foreign exchange market and the local stock markets are linked. It also provides support for a close relationship between financial and economic integration. Finally, the evidence shows that the financial crisis had a temporary effect on the long-run comovement between the various markets.

Financial Dependence and International Trade

Abstract: Does financial development translate into a comparative advantage in industries that use more external finance? The author uses industry-level data on firms' dependence on external finance for 36 industries and 56 countries to examine this question. It is shown that countries with better-developed financial systems have higher export shares and trade balances in industries that use more external finance. These results are robust to the use of alternative measures of external dependence and financial development and are not due to reverse causality or simultaneity bias.

A fuzzy dissolved gas analysis method for the diagnosis of multiple incipient faults in a transformer

Abstract: Dissolved gas analysis (DGA) of transformer oil has been one of the most useful techniques to detect the incipient faults. Various methods, such as the IEC codes, have been developed to interpret DGA results directly obtained from a chromatographer. Although these methods are widely used in the world, they sometimes fail to diagnose, especially when more than one fault exists in a transformer. This paper presents a fuzzy logic technique which can diagnose multiple faults in a transformer and quantitatively indicates the likelihood/severity of each fault. Insulation deterioration at each fault location can then be monitored closely according to its trend, which is important for a transformer in critical situation. Tests using this technique on a number of transformers have given promising results.

What is it to be a model

Abstract: There are various ways in which data for economic evaluations may be obtained, including via clinical trials and via economic modelling. There are a number of advantages and disadvantages associated with each method, though generally clinical trials have been preferred to economic models, largely because they are believed to give a better indication of cost-effectiveness given their reliance on real, albeit clinical trial, data. This brief article discusses this view setting out the main arguments for and against this stance. The general conclusion reached being that while clinical trial data are used in most, if not all, economic evaluations modelling will inevitably also be required.

Inconsistency Management in Software Engineering: Survey and Open Research Issues

Abstract: The development of complex software systems is a complex and lengthy activity that involves the participation and collaboration of many stakeholders (e.g. customers, users, analysts, designers, and developers). This results in many partial models of the developing system. These models can be inconsistent with each other since they describe the system from different perspectives and reflects the views of the stakeholders involved in their construction. Inconsistent software models can have negative and positive effects in the software development life-cycle. On the negative side, inconsistencies can delay and increase the cost of system development; do not guarantee some properties of the system, such as safety and reliability; and generate difficulties on system maintenance. On the positive side, inconsistencies can facilitate identification of some aspects of the system that need further analysis, assist with the specification of alternatives for the development of the system, and support elicitation of information about it. The software engineering community has proposed many techniques and methods to support the management of inconsistencies in various software models. In this paper, we present a survey of these techniques and methods. The survey is organized according to a conceptual framework which views inconsistency management as a process composed of six activities. These activities are the detection of overlaps, detection of inconsistencies, diagnosis of inconsistencies, handling of inconsistencies, tracking of inconsistencies, and specification and application of a management policy for inconsistencies. This paper also presents the main contributions of the research work that has been conducted to support each of the above activities and identifies the issues which are still open to further research.

Episodic memory and remembering in adults with Asperger syndrome.

Abstract: A group of adults with Asperger syndrome and an IQ-matched control group were compared in remember versus know recognition memory. Word frequency was also manipulated. Both groups showed superior recognition for low-frequency compared with high-frequency words, and in both groups this word frequency effect occurred in remembering, not in knowing. Nor did overall recognition differ between the two groups. However, recognition in the Asperger group was associated with less remembering, and more knowing, than in the control group. Since remembering reflects autonoetic consciousness, which is the hallmark of an episodic memory system, these results show that episodic memory is moderately impaired in individuals with Asperger syndrome even when overall recognition performance is not.

Financial Structure and Economic Development: Firm, Industry, and Country Evidence

Abstract: A country's level of financial development and the legal environment in which financial intermediaries and markets operate critically influence economic development. In countries whose financial sectors are more fully developed and whose legal systems protect the rights of outside investors, economies grow faster, industries dependent on external finance expand more quickly, new firms are created more easily, firms have more access to external financing, and firms grow faster. Beck, Demirguc-Kunt, Levine, and Maksimovic explore the relationship between financial structure - the degree to which a financial system is market- or bank-based - and economic development. They use three methodologies: · The cross-country approach uses cross-country data to assess whether economies grow faster with market- or bank-based systems. · The industry approach uses a country-industry panel to assess whether industries that depend heavily on external financing grow faster in market- or bank-based financial systems and whether financial structure influences the rate at which new firms are created. · The firm-level approach uses firm-level data across a broad selection of countries to test whether firms are more likely to grow beyond the rate predicted by internal resources and short-term borrowings in market- or bank-based financial systems. The cross-country regressions, the industry panel estimations, and the firm-level analyses provide remarkably consistent conclusions: · Financial structure is not an analytically useful way to distinguish financial systems. · Financial structure does not help us understand economic growth, industrial performance, or firm expansion. · The results are inconsistent with both market-based and bank-based views. In other words, economies do not grow faster, industries dependent on external financing do not expand faster, new firms are not created more easily, firms' access to external finance is not greater, and firms do not grow faster in either market- or bank-based financial systems. The authors find overwhelming evidence that the overall level of financial development and the legal environment in which financial intermediaries and markets operate critically influence economic development. This paper is a product of Finance, Development Research Group. The study was funded by the Bank's Research Support Budget under the research project Financial Structures and Economic Development (RPO 682-41). The authors may be contacted at tbeck@worldbank.org or ademirguckunt@worldbank.org.

Multidimensional Geographic Information Science

Abstract: Geographic Information Systems mainly tend to be two dimensional, thus limiting the applications. As GIS are being developed, researchers and practioners are finding new ways of making GIS three dimensional, even four dimensional in some instances, increasing their usability. This book focuses on the way in which GIS could be made `multidimensional' based on the modelling limitations of current 2D GIS. It suggests extending GIS to incorporate the third and fourth dimensions, as well as time (spatio-temporal GIS), using a variety of programming techniques and discusses current examples of multidimensional GIS.

Predicting uptake of a routine cervical smear test: A comparison of the health belief model and the theory of planned behaviour

Abstract: This paper reports on a study carried out to identify predictors of uptake of cervical screening among 142 women (59% response rate) in inner London Two social cognition models were used: The Health Belief Model (HBM; Becker, 1974) and the Theory of Planned Behaviour (TPB; Ajzen, 1991) and in addition anticipated affect following non-attendance for screening was assessed The TPB emerged as by far the superior model for predicting screening intentions, explaining 51% of the variance in comparison with only 4% explained by the HBM variables However, neither model was able to predict a significant amount of variance in uptake of screening three months later Possible reasons for the poor prediction of this type of behaviour are discussed

Factors related to stress and coping among Chinese nurses in Hong Kong.

Abstract: Few empirical studies have investigated the issues linked to Hong Kong nurses work-related health. The present study investigated factors related to stress and coping among Chinese nurses in Hong Kong. The researchers employed a cross-sectional survey and made within-group comparisons of nurses' stress and coping. Using stratified random sampling the researchers selected nurses from the mailing list of a local professional organization. One hundred and sixty-eight (33.6%) nurses responded. Nurses reported lower stress levels than other workers assessed with the same measure. Paediatric nurses reported the highest stress levels. Nurses at the lower grades reported higher stress levels than nurses at the higher grades. Single nurses had marginally higher stress scores than married nurses and females had slightly higher stress scores than males. However, none of these results were statistically significant. The respondents' major sources of stress were related to nursing issues like too much work, interpersonal relationships, and dealing with hospital administration. The respondents coped with their stresses by seeking support from friends and colleagues, using different cognitive strategies and through leisure activities. There was a statistically significant link between the respondents' stress and sickness levels. The results raise issues about the nature of nurses' working experiences.

Empirical studies of end-user information searching

Abstract: An empirical investigation of information retrieval (IR) using the MEDLINE1 database was carried out to study user behaviour, performance and to investigate the reasons for suboptimal searches The experimental subjects were drawn from two groups of final year medical students who differed in their knowledge of the search system (ie, novice and expert users) The subjects carried out four search tasks and their recall and precision performance was recorded Data was captured on the search strategies used, duration, and logs of submitted queries Differences were found between the groups for the performance measure of recall in only one of the four experimental tasks Overall performance was poor Analysis of strategies, timing data, and query logs showed that there were many different causes for search failure or success Poor searchers either gave up too quickly, employed few search terms, used only simple queries, or used the wrong search terms Good searchers persisted longer, used a larger, richer set of terms, constructed more complex queries, and were more diligent in evaluating the retrieved results However, individual performances were not correlated with all of these factors Poor performers frequently exhibited several factors of good searcher behaviour and failed for just one reason Overall end-user searching behaviour is complex and it seems that just one factor can cause poor performance, whereas good performance can result from suboptimal strategies that compensate for some difficulties The implications of the results for the design of IR interfaces are discussed

A multinational comparison of aphasia management practices.

Abstract: The effect of restructuring of healthcare on the quality, quantity, and nature of aphasia management is largely unknown. The current study is the first to examine access, diagnostic, treatment, and discharge patterns of patients with aphasia in Australia, Canada, the UK, the US private sector (US-Private), and the US Veterans Health Administration in the Department of Veterans Affairs (US-VA). The authors developed a 37-item survey to be completed by clinicians working with aphasic patients. The survey focused on eight areas: access to care, evaluation procedures, group treatment, number and duration of treatment sessions, limitations of the number of sessions, termination of treatment, follow-up practices, and resumption of treatment. 394 surveys were distributed and 175 were returned completed (44% return rate). Respondents represented a range of ages, work experiences, and work settings. There was considerable consistency among respondents from our five healthcare systems. Results suggest that patients may be routinely denied treatment in direct contradiction to the research literature. Just as we carefully monitor the progress of patients receiving our treatment, we are obliged to monitor the effects of managed care on our patients, fellow clinicians, and our profession.

Public Relations, Business News and the Reproduction of Corporate Elite Power

Abstract: This article discusses the rise of corporate public relations in Britain and offers an alternative explanation of how it has benefited the corporate sector. Most assessments of corporate PR tend to support traditional radical media accounts of strong corporate influence over media production and public opinion. All either argue or assume that PR is an effective form of ‘mind control’ with which to influence ‘the masses’. Against this account, this article instead argues that corporate PR has been more frequently used to gain a competitive advantage over rivals and has been primarily targeted at other corporate elites. This corporate elite focus has worked to further exclude non-corporate elites from participation in the production of financial and business news. As a result, a more general corporate advantage has been gained as much by exclusion as persuasion of the general public. After a brief discussion of the evidence and debates, these conclusions are illustrated with a case study of the Granada take...

The feasibility of universal screening for primary speech and language delay: findings from a systematic review of the literature

Abstract: This paper reports on a systematic review of the literature commissioned to examine the feasibility of universal screening for speech and language delay. The results, based on an examination of productivity figures, including positive predictive ability and likelihood ratio, indicate that a number of screening tests are adequate. Sensitivity was generally lower than specificity, and study quality was inversely related to both sensitivity and likelihood ratio, suggesting that it is easier to identify accurately children who do not have language and speech problems than those who do. The review concluded that there is insufficient evidence to warrant the introduction of universal screening at this stage. This paper discusses the type of data that would be needed to address this issue further and recommendations are made for alternative approaches to early identification.

Family dysfunction and bulimic psychopathology: the mediating role of shame.

Abstract: Objective Although disturbed family function has some association with bulimic psychopathology, the psychological mechanisms that account for that link are not clear. This study explores the hypothesis that shame acts as a mediator in that relationship, whereas shame-proneness is a moderator variable. Method The participants were 139 nonclinical women. Each completed measures of perceived family function, shame-proneness, internalized shame, and bulimic psychopathology. Regression analyses were used to test for the mediating and moderating effects of shame. Results The findings were compatible with a model where shame-proneness acts as a moderator and internalized shame is a perfect mediator in the link between paternal overprotection and bulimic attitudes. Conclusions The experience of shame appears to be a critical element in understanding the relationship between perceived family dysfunction and bulimic psychopathology. Where individuals perceive their families as problematic, it may be clinically valuable to focus on shame as a psychological consequence of that experience. © 2000 John Wiley & Sons, Inc. Int J Eat Disord 28: 84–89, 2000.

Suicide and self-harm in inpatient psychiatric units: a national survey of observation policies

Abstract: There is little empirical literature on observation as a psychiatric nursing procedure to prevent patients from harming themselves or others. National guidelines for this practice do not exist, with a consequence that local policies might be variable in content and quality. This paper reports a national survey of observation policies and usage based upon a stratified random sample of 27 psychiatric inpatient service providers in England and Wales. Extreme variation in terminology and practice was encountered. The terminological confusion is likely to reduce nurses' clarity about their responsibilities and increase risks to patients. Further variation exists from place to place as to whether, and to what extent, student nurses and family members should be entrusted with the responsibility to observe patients. More than one in 10 services of the sample still have no written observation policy, and four in 10 have no clinical recording system of the procedure in place. Nurses commonly amend the procedure and terminology on an ad hoc basis. The results of this survey confirm that the Department of Health should set national standards for the policies and procedures for patient observation and that as an interim step practice guidance should be issued to all nurses (and other mental health workers) involved in this procedure.

Soothing pain-elicited distress in Chinese neonates.

Abstract: Objective. To test the effect of nonnutri- tive sucking (NNS), music therapy (MT), and combined NNS and MT (NNS 1 MT), versus no intervention, on heart rate, transcutaneous oxygen (TcPaO2) levels, and pain behavior of neonates in intensive care units having blood taken by a heel-stick procedure. Methodology. A within-subjects, counter-balancing, repeated-measures design conducted in a government- funded hospital in Hong Kong, comparing TcPaO2 levels, heart rate, and pain behavior outcomes in 27 neonates. Results. Repeated-measures multivariate analysis of variance revealed statistically significant differences in outcomes across all interventions (Wilk's l 5 .142; F (3,27) 5 31.82; h2 5 .47). One-way analysis of variance revealed that the 3 comfort interventions significantly reduced neonates' heart rate (Wilk's l 5 .647; F (2,27) 5 18.93; h2 5 .35), improved their TcPaO2 levels (Wilk's l 5 .481; F (2,27) 5 37.42; h2 5 .51), and reduced their pain behavior (Wilk's l 5 .312; F (2,27) 5 76.42; h2 5 .68). Posthoc scheffe tests revealed that NNS 1 MT had the strongest effect on neonates' TcPaO2 levels and pain be- havior; MT alone had the strongest effect on neonates' heart rate. Conclusions. Health professionals using NNS 1 MT when doing heel-sticks can improve the TcPaO2 levels of neonates and reduce their pain. Using MT alone can improve the heart rate of neonates. Pediatrics 2000;105(4). URL: http://www.pediatrics.org/cgi/content/full/105/4/ e49; psychological interventions, neonates, pain.

Concept analysis: chronic fatigue.

Abstract: This concept analysis attempts to clarify and analyse the concept 'chronic fatigue' and does so by utilizing the framework outlined by Walker and Avant (1995). The aim is to use this work to underpin future research into the care of patients suffering from chronic obstructive pulmonary disease (COPD). The literature revealed no universal definition of fatigue and a confusion exists between fatigue and chronic fatigue. Three concept analyses are considered to assist clarification. Everyday meanings are sought as well as meanings revealed in poetry. A continuum from tired to exhausted is identified and definitions offered. Defining attributes are decided upon which will be used as an operational definition in later research. Constructed cases are created; antecedents and consequences are devised from the literature; scales, tests and descriptions of general appearance which appear within the literature are considered as empirical referents. However, whilst assisting with the understanding of the concept and future research, the complexity of this subject is still evident.

The Bosman Ruling and the Emergence of a Single Market in Soccer talent.

Abstract: This paper discusses the effect of the ruling by the European Court of Justice in the Bosman case which delivered freedom of contract to professional soccer players. The result is examined in the context of modern investment theory where contracts between club and player are considered as options to renegotiate the contract or to sell the player to another party. The effects of the ruling are reconsidered in this light and the reaction of the soccer world to these effects are discussed.

Numerical Investigation of a Stability Theorem Arisingfrom the 2-Dimensional Analysis of an Iterative Optimal ControlAlgorithm

Abstract: Because many optimal control problems require solution using iterative procedures they fall naturally in the realm of 2-D systems where the two dimensions are response time horizon and iteration index, respectively. The paper uses this observation to employ 2-D systems theory, in the form of unit memory repetitive process techniques, to analyse local stability and convergence behaviour of a continuous optimal control algorithm based on dynamic system optimisation and parameter estimation. Existing work is extended to incorporate unmatched terminal constraints. Necessary and sufficient conditions for stability are obtained whose evaluation require the solution of a difficult eigenvalue problem. The paper shows how solutions can be achieved using numerical and graphical facilities of MATLAB.

Harmonics load signature recognition by wavelets transforms

Abstract: Power quality has become an important concern both to the utilities and their customers. End user equipment is often more sensitive to disturbances that exist both on the supplying power system and within the customer facilities. Power quality embraces problems caused by harmonics, over or under-voltages, or supply discontinuities. Harmonics are caused by all sorts of nonlinear loads. In order to fully understand the problems caused by harmonics pollution, an effective means of identifying sources of power harmonics is important. The authors used fuzzy numbers for harmonics signature recognition. In this paper, the authors have made use of new developments in wavelets so that each type of current waveform polluted with power harmonics can well be represented by a normalised energy vector consisting of five elements. Furthermore, a mixture of harmonics load can also be represented by a corresponding vector. This paper describes the mathematics and algorithms for arriving at the vectors, forming a strong foundation for real-time harmonics signature recognition, in particular useful to the re-structuring of the whole electric power industry.

Internalising and externalising children's behaviour problems in Britain and the US: relationships to family resources

Abstract: A large sample of British children (n=994) of varying ages (7–18 years) and a large sample of American children (n=886) of varying ages (7–16 years) were rated by their mothers using respectively the Rutter Child Scale A and the Behaviour Problems Index both of which cover a variety of behavioural problems. Factor analysis of the behavioural scales distinguished externalising and internalising dimensions of behaviour in both countries. We examined whether children's experiences of family change, cognitive ability and family adversity including economic deprivation were associated with differences in the prevalence of the behavioural dimensions. Mean cognitive scores decreased significantly with increasing level of externalising behavioural problems in British and American children but showed no significant relationship to levels of internalising behaviour problems in either sample. Among American children internalising and externalising behavioural problems were related to experience of non-intact family structures and measures of family adversity. Externalising behavioural problems were related to measures of family adversity among British boys and girls but were only related to experience of non-intact family structures in the sample of British girls. Among British girls, internalising behavioural problems were also related to non-intact family structures. The associations between non-intact family structures and behavioural problems were independent of measures of economic deprivation in both samples of children. This study documents some of the background factors which affect children's behavioural and cognitive outcomes. Unlike children's family structure economic deprivation can be influenced through policy intervention, and the analysis supports the view that relieving economic deprivation would help improve children's behavioural outcomes. Copyright © 2000 John Wiley & Sons, Ltd.

Software engineering: community and culture

Abstract: Ideas and techniques from the social sciences can improve the theory and practice of the software engineering discipline. To illustrate the contributions this cross-pollination has made, the authors focus on the nature of paradigms and software quality management systems. Their studies underscore the importance of community in how new technical ideas become accepted, how despite software engineers too often prefer polemic to evidence, and the primacy given to the local guru that transcends formal organizational structures.

Hedging in the Freight Futures Market

Abstract: Time-varying hedge ratios have been found successful in reducing spot market risk in different commodity and financial futures markets. This article extends the empirical evidence by investigating the same question for a futures market based on services, the Baltic International Freight Futures Exchange (BIFFEX) market. BIFFEX contracts are cash settled against the Baltic Freight Index (BFI), a weighted average dry-cargo freight rate index, compiled from actual freight rates on 11 shipping routes which are dissimilar in terms of vessel sizes and transported commodities. GARCH and augmented GARCH models are introduced to investigate the hedging effectiveness of the futures contract across the different shipping routes. Time-varying hedge ratios outperform alternative specifications in reducing market risk, in four shipping routes, but they fail to reduce the riskiness of the spot position, to the extent found for other markets in the literature. This is explained by the fact that freight futures contracts are employed as a cross-hedge against the fluctuations of the individual shipping routes that constitute the underlying index. There is large basis risk, and the rate fluctuations on these routes may not be accurately tracked by the futures prices. A recent change in the contract’s underlying index appears to have substantially increased hedging effectiveness, but not trading activity as yet.