Knowledge based improvement:simulation and artificial intelligence for identifying and improving human decision-making in an operations systems

The performance of most operations systems is significantly affected by the interaction of human decision-makers. A methodology, based on the use of visual interactive simulation (VIS) and artificial intelligence (AI), is described that aims to identify and improve human decision-making in operations systems. The methodology, known as 'knowledge-based improvement' (KBI), elicits knowledge from a decision-maker via a VIS and then uses AI methods to represent decision-making. By linking the VIS and AI representation, it is possible to predict the performance of the operations system under different decision-making strategies and to search for improved strategies. The KBI methodology is applied to the decision-making surrounding unplanned maintenance operations at a Ford Motor Company engine assembly plant.

Brady et al.'s (2005) service evaluation models: A replication and extension in China

The research described in this study replicates and extends the Brady et al., [Brady, M. K., Knight, G. A., Cronin Jr. J. Toma, G., Hult, M. and Keillor, B. D. (2005), emoving the Contextual Lens: A Multinational, Mult-setting Comparison of Service Evaluation Models, Journal of Retailing, 81(3), pp. 215-230] study suggestion that future research in service evaluations should focus on emerging service economies such as China. The intent of the research was to examine the suitability of the models suggested by Brady and colleagues in the Chinese market. The replication somewhat successfully duplicated their finding as to the superiority of the comprehensive service evaluation model. Additionally, we also sought to examine as to whether the service evaluation model is gender invariant. Our findings indicate that there are significant differences between gender. These findings are discussed relative to the limitations associated with the study.

Forecasting exchange rates with linear and nonlinear models

In this paper the exchange rate forecasting performance of neural network models are evaluated against random walk and a range of time series models. There are no guidelines available that can be used to choose the parameters of neural network models and therefore the parameters are chosen according to what the researcher considers to be the best. Such an approach, however, implies that the risk of making bad decisions is extremely high which could explain why in many studies neural network models do not consistently perform better than their time series counterparts. In this paper through extensive experimentation the level of subjectivity in building neural network models is considerably reduced and therefore giving them a better chance of performing well. Our results show that in general neural network models perform better than traditionally used time series models in forecasting exchange rates.

A study of the effect of harmonics in the system on the performance of residual current-operated circuit-breakers and electromechanical overcurrent relays

Residual current-operated circuit-breakers (RCCBs) have proved useful devices for the protection of both human beings against ventricular fibrillation and installations against fire. Although they work well with sinusoidal waveforms, there is little published information on their characteristics. Due to shunt connected non-linear devices, not the least of which is the use of power electronic equipment, the supply is distorted. Consequently, RCCBs as well as other protection relays are subject to non-sinusoidal current waveforms. Recent studies showed that RCCBs are greatly affected by harmonics, however the reasons for this are not clear. A literature search has also shown that there are inconsistencies in the analysis of the effect of harmonics on protection relays. In this work, the way RCCBs operate is examined, then a model is built with the aim of assessing the effect of non-sinusoidal current on RCCBs. Tests are then carried out on a number of RCCBs and these, when compared with the results from the model showed good correlation. In addition, the model also enables us to explain the RCCBs characteristics for pure sinusoidal current. In the model developed, various parameters are evaluated but special attention is paid to the instantaneous value of the current and the tripping mechanism movement. A similar assessment method is then used to assess the effect of harmonics on two types of protection relay, the electromechanical instantaneous relay and time overcurrent relay. A model is built for each of them which is then simulated on the computer. Tests results compare well with the simulation results, and thus the model developed can be used to explain the relays behaviour in a harmonics environment. The author's models, analysis and tests show that RCCBs and protection relays are affected by harmonics in a way determined by the waveform and the relay constants. The method developed provides a useful tool and the basic methodology to analyse the behaviour of RCCBs and protection relays in a harmonics environment. These results have many implications, especially the way RCCBs and relays should be tested if harmonics are taken into account.

Optimization of chemical plant simulation using double collocation

A method has been constructed for the solution of a wide range of chemical plant simulation models including differential equations and optimization. Double orthogonal collocation on finite elements is applied to convert the model into an NLP problem that is solved either by the VF 13AD package based on successive quadratic programming, or by the GRG2 package, based on the generalized reduced gradient method. This approach is termed simultaneous optimization and solution strategy. The objective functional can contain integral terms. The state and control variables can have time delays. Equalities and inequalities containing state and control variables can be included into the model as well as algebraic equations and inequalities. The maximum number of independent variables is 2. Problems containing 3 independent variables can be transformed into problems having 2 independent variables using finite differencing. The maximum number of NLP variables and constraints is 1500. The method is also suitable for solving ordinary and partial differential equations. The state functions are approximated by a linear combination of Lagrange interpolation polynomials. The control function can either be approximated by a linear combination of Lagrange interpolation polynomials or by a piecewise constant function over finite elements. The number of internal collocation points can vary by finite elements. The residual error is evaluated at arbitrarily chosen equidistant grid-points, thus enabling the user to check the accuracy of the solution between collocation points, where the solution is exact. The solution functions can be tabulated. There is an option to use control vector parameterization to solve optimization problems containing initial value ordinary differential equations. When there are many differential equations or the upper integration limit should be selected optimally then this approach should be used. The portability of the package has been addressed converting the package from V AX FORTRAN 77 into IBM PC FORTRAN 77 and into SUN SPARC 2000 FORTRAN 77. Computer runs have shown that the method can reproduce optimization problems published in the literature. The GRG2 and the VF I 3AD packages, integrated into the optimization package, proved to be robust and reliable. The package contains an executive module, a module performing control vector parameterization and 2 nonlinear problem solver modules, GRG2 and VF I 3AD. There is a stand-alone module that converts the differential-algebraic optimization problem into a nonlinear programming problem.

Tense, aspect and modality in first and second language

Time after time… and aspect and mood. Over the last twenty five years, the study of time, aspect and - to a lesser extent - mood acquisition has enjoyed increasing popularity and a constant widening of its scope. In such a teeming field, what can be the contribution of this book? We believe that it is unique in several respects. First, this volume encompasses studies from different theoretical frameworks: functionalism vs generativism or function-based vs form-based approaches. It also brings together various sub-fields (first and second language acquisition, child and adult acquisition, bilingualism) that tend to evolve in parallel rather than learn from each other. A further originality is that it focuses on a wide range of typologically different languages, and features less studied languages such as Korean and Bulgarian. Finally, the book gathers some well-established scholars, young researchers, and even research students, in a rich inter-generational exchange, that ensures the survival but also the renewal and the refreshment of the discipline. The book at a glance The first part of the volume is devoted to the study of child language acquisition in monolingual, impaired and bilingual acquisition, while the second part focuses on adult learners. In this section, we will provide an overview of each chapter. The first study by Aviya Hacohen explores the acquisition of compositional telicity in Hebrew L1. Her psycholinguistic approach contributes valuable data to refine theoretical accounts. Through an innovating methodology, she gathers information from adults and children on the influence of definiteness, number, and the mass vs countable distinction on the constitution of a telic interpretation of the verb phrase. She notices that the notion of definiteness is mastered by children as young as 10, while the mass/count distinction does not appear before 10;7. However, this does not entail an adult-like use of telicity. She therefore concludes that beyond definiteness and noun type, pragmatics may play an important role in the derivation of Hebrew compositional telicity. For the second chapter we move from a Semitic language to a Slavic one. Milena Kuehnast focuses on the acquisition of negative imperatives in Bulgarian, a form that presents the specificity of being grammatical only with the imperfective form of the verb. The study examines how 40 Bulgarian children distributed in two age-groups (15 between 2;11-3;11, and 25 between 4;00 and 5;00) develop with respect to the acquisition of imperfective viewpoints, and the use of imperfective morphology. It shows an evolution in the recourse to expression of force in the use of negative imperatives, as well as the influence of morphological complexity on the successful production of forms. With Yi-An Lin’s study, we concentrate both on another type of informant and of framework. Indeed, he studies the production of children suffering from Specific Language Impairment (SLI), a developmental language disorder the causes of which exclude cognitive impairment, psycho-emotional disturbance, and motor-articulatory disorders. Using the Leonard corpus in CLAN, Lin aims to test two competing accounts of SLI (the Agreement and Tense Omission Model [ATOM] and his own Phonetic Form Deficit Model [PFDM]) that conflicts on the role attributed to spellout in the impairment. Spellout is the point at which the Computational System for Human Language (CHL) passes over the most recently derived part of the derivation to the interface components, Phonetic Form (PF) and Logical Form (LF). ATOM claims that SLI sufferers have a deficit in their syntactic representation while PFDM suggests that the problem only occurs at the spellout level. After studying the corpus from the point of view of tense / agreement marking, case marking, argument-movement and auxiliary inversion, Lin finds further support for his model. Olga Gupol, Susan Rohstein and Sharon Armon-Lotem’s chapter offers a welcome bridge between child language acquisition and multilingualism. Their study explores the influence of intensive exposure to L2 Hebrew on the development of L1 Russian tense and aspect morphology through an elicited narrative. Their informants are 40 Russian-Hebrew sequential bilingual children distributed in two age groups 4;0 – 4;11 and 7;0 - 8;0. They come to the conclusion that bilingual children anchor their narratives in perfective like monolinguals. However, while aware of grammatical aspect, bilinguals lack the full form-function mapping and tend to overgeneralize the imperfective on the principles of simplicity (as imperfective are the least morphologically marked forms), universality (as it covers more functions) and interference. Rafael Salaberry opens the second section on foreign language learners. In his contribution, he reflects on the difficulty L2 learners of Spanish encounter when it comes to distinguishing between iterativity (conveyed with the use of the preterite) and habituality (expressed through the imperfect). He examines in turn the theoretical views that see, on the one hand, habituality as part of grammatical knowledge and iterativity as pragmatic knowledge, and on the other hand both habituality and iterativity as grammatical knowledge. He comes to the conclusion that the use of preterite as a default past tense marker may explain the impoverished system of aspectual distinctions, not only at beginners but also at advanced levels, which may indicate that the system is differentially represented among L1 and L2 speakers. Acquiring the vast array of functions conveyed by a form is therefore no mean feat, as confirmed by the next study. Based on the prototype theory, Kathleen Bardovi-Harlig’s chapter focuses on the development of the progressive in L2 English. It opens with an overview of the functions of the progressive in English. Then, a review of acquisition research on the progressive in English and other languages is provided. The bulk of the chapter reports on a longitudinal study of 16 learners of L2 English and shows how their use of the progressive expands from the prototypical uses of process and continuousness to the less prototypical uses of repetition and future. The study concludes that the progressive spreads in interlanguage in accordance with prototype accounts. However, it suggests additional stages, not predicted by the Aspect Hypothesis, in the development from activities and accomplishments at least for the meaning of repeatedness. A similar theoretical framework is adopted in the following chapter, but it deals with a lesser studied language. Hyun-Jin Kim revisits the claims of the Aspect Hypothesis in relation to the acquisition of L2 Korean by two L1 English learners. Inspired by studies on L2 Japanese, she focuses on the emergence and spread of the past / perfective marker ¬–ess- and the progressive – ko iss- in the interlanguage of her informants throughout their third and fourth semesters of study. The data collected through six sessions of conversational interviews and picture description tasks seem to support the Aspect Hypothesis. Indeed learners show a strong association between past tense and accomplishments / achievements at the start and a gradual extension to other types; a limited use of past / perfective marker with states and an affinity of progressive with activities / accomplishments and later achievements. In addition, - ko iss– moves from progressive to resultative in the specific category of Korean verbs meaning wear / carry. While the previous contributions focus on function, Evgeniya Sergeeva and Jean-Pierre Chevrot’s is interested in form. The authors explore the acquisition of verbal morphology in L2 French by 30 instructed native speakers of Russian distributed in a low and high levels. They use an elicitation task for verbs with different models of stem alternation and study how token frequency and base forms influence stem selection. The analysis shows that frequency affects correct production, especially among learners with high proficiency. As for substitution errors, it appears that forms with a simple structure are systematically more frequent than the target form they replace. When a complex form serves as a substitute, it is more frequent only when it is replacing another complex form. As regards the use of base forms, the 3rd person singular of the present – and to some extent the infinitive – play this role in the corpus. The authors therefore conclude that the processing of surface forms can be influenced positively or negatively by the frequency of the target forms and of other competing stems, and by the proximity of the target stem to a base form. Finally, Martin Howard’s contribution takes up the challenge of focusing on the poorer relation of the TAM system. On the basis of L2 French data obtained through sociolinguistic interviews, he studies the expression of futurity, conditional and subjunctive in three groups of university learners with classroom teaching only (two or three years of university teaching) or with a mixture of classroom teaching and naturalistic exposure (2 years at University + 1 year abroad). An analysis of relative frequencies leads him to suggest a continuum of use going from futurate present to conditional with past hypothetic conditional clauses in si, which needs to be confirmed by further studies. Acknowledgements The present volume was inspired by the conference Acquisition of Tense – Aspect – Mood in First and Second Language held on 9th and 10th February 2008 at Aston University (Birmingham, UK) where over 40 delegates from four continents and over a dozen countries met for lively and enjoyable discussions. This collection of papers was double peer-reviewed by an international scientific committee made of Kathleen Bardovi-Harlig (Indiana University), Christine Bozier (Lund Universitet), Alex Housen (Vrije Universiteit Brussel), Martin Howard (University College Cork), Florence Myles (Newcastle University), Urszula Paprocka (Catholic University of Lublin), †Clive Perdue (Université Paris 8), Michel Pierrard (Vrije Universiteit Brussel), Rafael Salaberry (University of Texas at Austin), Suzanne Schlyter (Lund Universitet), Richard Towell (Salford University), and Daniel Véronique (Université d’Aix-en-Provence). We are very much indebted to that scientific committee for their insightful input at each step of the project. We are also thankful for the financial support of the Association for French Language Studies through its workshop grant, and to the Aston Modern Languages Research Foundation for funding the proofreading of the manuscript.

Wealth effects of mergers and acquisitions for US firms: using alternative pricing models

This empirical study employs a different methodology to examine the change in wealth associated with mergers and acquisitions (M&As) for US firms. Specifically, we employ the standard CAPM, the Fama-French three-factor model and the Carhart four-factor models within the OLS and GJR-GARCH estimation methods to test the behaviour of the cumulative abnormal returns (CARs). Whilst the standard CAPM captures the variability of stock returns with the overall market, the Fama-French factors capture the risk factors that are important to investors. Additionally, augmenting the Fama-French three-factor model with the Carhart momentum factor to generate the four-factor captures additional pricing elements that may affect stock returns. Traditionally, estimates of abnormal returns (ARs) in M&As situations rely on the standard OLS estimation method. However, the standard OLS will provide inefficient estimates of the ARs if the data contain ARCH and asymmetric effects. To minimise this problem of estimation efficiency we re-estimated the ARs using GJR-GARCH estimation method. We find that there is variation in the results both as regards the choice models and estimation methods. Besides these variations in the estimated models and the choice of estimation methods, we also tested whether the ARs are affected by the degree of liquidity of the stocks and the size of the firm. We document significant positive post-announcement cumulative ARs (CARs) for target firm shareholders under both the OLS and GJR-GARCH methods across all three methodologies. However, post-event CARs for acquiring firm shareholders were insignificant for both sets of estimation methods under the three methodologies. The GJR-GARCH method seems to generate larger CARs than those of the OLS method. Using both market capitalization and trading volume as a measure of liquidity and the size of the firm, we observed strong return continuations in the medium firms relative to small and large firms for target shareholders. We consistently observed market efficiency in small and large firm. This implies that target firms for small and large firms overreact to new information resulting in a more efficient market. For acquirer firms, our measure of liquidity captures strong return continuations for small firms under the OLS estimates for both CAPM and Fama-French three-factor models, whilst under the GJR-GARCH estimates only for Carhart model. Post-announcement bootstrapping simulated CARs confirmed our earlier results.

Humans:the missing link in manufacturing simulation?

Computer based discrete event simulation (DES) is one of the most commonly used aids for the design of automotive manufacturing systems. However, DES tools represent machines in extensive detail, while only representing workers as simple resources. This presents a problem when modelling systems with a highly manual work content, such as an assembly line. This paper describes research at Cranfield University, in collaboration with the Ford Motor Company, founded on the assumption that human variation is the cause of a large percentage of the disparity between simulation predictions and real world performance. The research aims to improve the accuracy and reliability of simulation prediction by including models of human factors.

Brady et al.'s (2005) service evaluation models: A replication and extension in China

The research described in this study replicates and extends the Brady et al., [Brady, M. K., Knight, G. A., Cronin Jr. J. Toma, G., Hult, M. and Keillor, B. D. (2005), emoving the Contextual Lens: A Multinational, Mult-setting Comparison of Service Evaluation Models, Journal of Retailing, 81(3), pp. 215-230] study suggestion that future research in service evaluations should focus on emerging service economies such as China. The intent of the research was to examine the suitability of the models suggested by Brady and colleagues in the Chinese market. The replication somewhat successfully duplicated their finding as to the superiority of the comprehensive service evaluation model. Additionally, we also sought to examine as to whether the service evaluation model is gender invariant. Our findings indicate that there are significant differences between gender. These findings are discussed relative to the limitations associated with the study.

New career models in UK professional service firms:from up-or-out to up-and-going-nowhere?

In this paper, we empirically examine how professional service firms are adapting their promotion and career models to new market and institutional pressures, without losing the benefits of the traditional up-or-out tournament. Based on an in-depth qualitative study of 10 large UK based law firms we find that most of these firms do not have a formal up-or-out policy but that the up-or-out rule operates in practice. We also find that most firms have introduced alternative roles and a novel career policy that offers a holistic learning and development deal to associates without any expectation that unsuccessful candidates for promotion to partner should quit the firm. While this policy and the new roles formally contradict the principle of up-or-out by creating permanent non-partner positions, in practice they coexist. We conclude that the motivational power of the up-or-out tournament remains intact, notwithstanding the changes to the internal labour market structure of these professional service firms.

Selection of simulation tools for improving supply chain performance

Simulation is an effective method for improving supply chain performance. However, there is limited advice available to assist practitioners in selecting the most appropriate method for a given problem. Much of the advice that does exist relies on custom and practice rather than a rigorous conceptual or empirical analysis. An analysis of the different modelling techniques applied in the supply chain domain was conducted, and the three main approaches to simulation used were identified; these are System Dynamics (SD), Discrete Event Simulation (DES) and Agent Based Modelling (ABM). This research has examined these approaches in two stages. Firstly, a first principles analysis was carried out in order to challenge the received wisdom about their strengths and weaknesses and a series of propositions were developed from this initial analysis. The second stage was to use the case study approach to test these propositions and to provide further empirical evidence to support their comparison. The contributions of this research are both in terms of knowledge and practice. In terms of knowledge, this research is the first holistic cross paradigm comparison of the three main approaches in the supply chain domain. Case studies have involved building ‘back to back’ models of the same supply chain problem using SD and a discrete approach (either DES or ABM). This has led to contributions concerning the limitations of applying SD to operational problem types. SD has also been found to have risks when applied to strategic and policy problems. Discrete methods have been found to have potential for exploring strategic problem types. It has been found that discrete simulation methods can model material and information feedback successfully. Further insights have been gained into the relationship between modelling purpose and modelling approach. In terms of practice, the findings have been summarised in the form of a framework linking modelling purpose, problem characteristics and simulation approach.

Development of a risk-oriented strategic sourcing (ROSS) framework for the construction and electronics manufacturing industries

Strategic sourcing has increased in importance in recent years, and now plays an important role in companies’ planning. The current volatility in supply markets means companies face multiple challenges involving lock-in situations, supplier bankruptcies or supply security issues. In addition, their exposure can increase due to natural disasters, as witnessed recently in the form of bird flu, volcanic ash and tsunamis. Therefore, the primary focus of this study is risk management in the context of strategic sourcing. The study presents a literature review on sourcing based on the 15 years from 1998–2012, and considers 131 academic articles. The literature describes strategic sourcing as a strategic, holistic process in managing supplier relationships, with a long-term focus on adding value to the company and realising competitive advantage. Few studies discovered the real risk impact and status of risk management in strategic sourcing, and evaluation across countries and industries was limited, with the construction sector particularly under-researched. This methodology is founded on a qualitative study of twenty cases across Ger-many and the United Kingdom from the construction sector and electronics manufacturing industries. While considering risk management in the context of strategic sourcing, the thesis takes into account six dimensions that cover trends in strategic sourcing, theoretical and practical sourcing models, risk management, supply and demand management, critical success factors and the strategic supplier evaluation. The study contributes in several ways. First, recent trends are traced and future needs identified across the research dimensions of countries, industries and companies. Second, it evaluates critical success factors in contemporary strategic sourcing. Third, it explores the application of theoretical and practical sourcing models in terms of effectiveness and sustainability. Fourth, based on the case study findings, a risk-oriented strategic sourcing framework and a model for strategic sourcing are developed. These are based on the validation of contemporary requirements and a critical evaluation of the existing situation. It contemplates the empirical findings and leads to a structured process to manage risk in strategic sourcing. The risk-oriented framework considers areas such as trends, corporate and sourcing strategy, critical success factors, strategic supplier selection criteria, risk assessment, reporting, strategy alignment and reporting. The proposed model highlights the essential dimensions in strategic sourcing and guides us to a new definition of strategic sourcing supported by this empirical study.

Hypoxia-inducible factor (HIF) network:insights from mathematical models

Oxygen is a crucial molecule for cellular function. When oxygen demand exceeds supply, the oxygen sensing pathway centred on the hypoxia inducible factor (HIF) is switched on and promotes adaptation to hypoxia by up-regulating genes involved in angiogenesis, erythropoiesis and glycolysis. The regulation of HIF is tightly modulated through intricate regulatory mechanisms. Notably, its protein stability is controlled by the oxygen sensing prolyl hydroxylase domain (PHD) enzymes and its transcriptional activity is controlled by the asparaginyl hydroxylase FIH (factor inhibiting HIF-1).To probe the complexity of hypoxia-induced HIF signalling, efforts in mathematical modelling of the pathway have been underway for around a decade. In this paper, we review the existing mathematical models developed to describe and explain specific behaviours of the HIF pathway and how they have contributed new insights into our understanding of the network. Topics for modelling included the switch-like response to decreased oxygen gradient, the role of micro environmental factors, the regulation by FIH and the temporal dynamics of the HIF response. We will also discuss the technical aspects, extent and limitations of these models. Recently, HIF pathway has been implicated in other disease contexts such as hypoxic inflammation and cancer through crosstalking with pathways like NF?B and mTOR. We will examine how future mathematical modelling and simulation of interlinked networks can aid in understanding HIF behaviour in complex pathophysiological situations. Ultimately this would allow the identification of new pharmacological targets in different disease settings.

Culture and the psychological impacts of natural disasters: Implications for disaster management and disaster mental health

In recent decades, natural disasters have caused extensive losses and damages to human psychological wellbeing, economy, and society. It has been argued that cultural factors such as social values, traditions, and attachment to a location influence communities facing and responding to natural disasters. However, the issue of culture in disaster mental health seems to have received limited attention in policy and practice. This review highlights the importance of cultural background in the assessment of vulnerability to the psychological impacts of disasters, disaster preparedness, and provision of disaster mental health services. In particular, this paper suggests the importance of cultural competence in the planning and delivery of effective disaster mental health services. In order to address the varying circumstances of people with different cultural backgrounds, disaster mental health services must be developed in a culturally sensitive manner. Development of culturally competent disaster mental health services requires significant changes in policy making, administration, and direct service provision

Leaders' sensemaking under crises:emerging cognitive consensus over time within management teams

When facing a crisis, leaders' sensemaking can take a considerable amount of time due to the need to develop consensus in how to deal with it so that vision formation and sensegiving can take place. However, research into emerging cognitive consensus when leaders deal with a crisis over time is lacking. This is limiting a detailed understanding of how organizations respond to crises. The findings, based on a longitudinal analysis of cognitive maps within three management teams at a single organization, highlight considerable individual differences in cognitive content when starting to make sense of a crisis. Evidence for an emerging viable prescriptive mental model for the future was found, but not so much in the management as a whole. Instead, the findings highlight increasing cognitive consensus based on similarities in objectives and cause-effect beliefs within well-defined management teams over time.