Browsing by Author "Towriss, John"

Now showing 1 - 9 of 9
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    The development of an integrated routing and carbon dioxide emissions model for goods vehicles
    (Cranfield University, 2007-11) Palmer, Andrew; Towriss, John
    The issues of global warming and climate change are a worldwide concern and the UK government has committed itself to major reductions in CO2 emissions, the most significant of the six greenhouse gases. Road transport currently accounts for about 22% of total UK emissions of CO2, and has been steadily rising. Therefore, initiatives are required to try and reduce the gas emissions in this sector. The aim of this research has been to develop a computer based vehicle routing model that calculates the overall amount of CO2 emitted from road journeys, as well as time and distance. The model has been used to examine a number of delivery strategies to assess how CO2 emissions vary. The aim has not been to produce new mathematical theories, but to produce an innovative basis for routing which will provide new information and knowledge about how CO2 emissions vary for different minimisation and congestion criteria. The approach used in this research brings together elements from transportation planning and environmental modelling combined with logistics based vehicle routing techniques. The model uses a digitised road network containing predicted traffic volumes, to which speed flow formulae are applied so that a good representation of speed can be generated on each of the roads. This means that the model is uniquely able to address the issue of congestion in the context of freight vehicle routing. It uses driving cycle data to apply variability to the generated speeds to reflect acceleration and deceleration so that fuel consumption, and therefore CO2, can be estimated. Integrated within the model are vehicle routing heuristics to enable routes to be produced which minimise the specified criterion of time, distance or CO2. The results produced by the model show that there is a potential to reduce CO2 emissions by about 5%. However, when other transport externalities are considered overall benefits are dependent on road traffic volumes.
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    The economic appraisal of transport projects: the incorporation of disabled access
    (Cranfield University, 2007-08) Maynard, Alice; Towriss, John
    The importance for disabled people of accessible transport is now widely recognised, as is the reality that this also benefits many non-disabled people. Many previous commentaries offer a qualitative perspective, but quantitative evidence, particularly of benefits to the population as a whole, has been lacking. This research, underpinned by the Social Model of disability, established that the absence of such evidence creates a barrier to the inclusion of disabled people in mainstream transport. Further, it demonstrates that there is a way to remove this barrier: by applying stated preference techniques, the benefits of providing access to transport systems can be robustly monetised and successfully incorporated into the economic appraisal of transport projects. A multiple-case study of tram systems investigated how practitioners currently incorporate disabled access into project appraisals. Analysis showed that isomorphic forces identified by new institutional theory have led to similarity in practice, with the effect that ways of incorporating the costs of disabled access are well established, but ways of incorporating the benefits remain unclear. Resulting benefit:cost ratios, often apparently unfavourable, may be misleading. A systematic literature review catalogued methods for valuing non-market goods, and from these identified methods transferable to disabled access. Stated preference, a method of monetisation common in the transport environment, emerged as an appropriate method, with discrete choice modelling a suitable technique. A discrete choice experiment enabled calculation of monetary values for platform-to-platform access at stations. Using a cross-section of the population and addressing socioeconomic factors such as age, disability, and attitudes to disabled people, willingness-to-pay figures were derived for access methods suited to disabled people‘s needs. Finally, these willingness-to-pay figures were incorporated into two appraisals. The amended benefit:cost ratios more accurately represent the value of access provision, and the figures incidentally enable the relative values of different access options to be distinguished.
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    The effectiveness of police driver training on attitudes, beliefs and skills
    (Cranfield University, 1994-03) Evans, D. S.; Towriss, John
    The research undertook an analysis of the effectiveness of police driver training in the development of appropriate driver attitudes and skills in terms of the objectives of the training. The research focused upon the Standard/Response course of the Essex Police. Trainees attitudes and skill, levels were measured at the beginning and after each phase of training. An assessment of the stability and longevity of attitudes and skill levels was made 3-10 months after the training. In addition, the influence of police driving instructors and police recruitment policy on the development of attitudes was made. From the research, an evaluation has also been made of the effectiveness of different methods of researching and measuring an individual's attitude towards a particular behaviour, having used direct, semi-direct, and indirect methods of attitude measurement.
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    Monetary valuation of the environmental impacts of road transport : a stated preference approach
    (Cranfield University, 1998-09) Nelson, P. S.; Cordey-Hayes, M.; Towriss, John
    The impact of road transport and road transport infrastructure on the environment is an important public issue in the United Kingdom today. Economists have suggested that the present Trunk Road appraisal process undervalues the environmental impact of road schemes because environmental impacts are not included in the monetary cost-benefit process, i.e. they are externalised. Furthermore, critics state that the present evaluation process is complicated by the number and type of qualitative and quantitative measures of environmental impact, this leads to confusion and non-standardisation in the decision-making process. In answer to these criticisms it has been suggested that monetary values of environmental impacts should be incorporated into the Trunk Road appraisal process, i.e. placing environmental benefits or losses into the cost-benefit framework and hence simplifying the decision-making process. This research identified the present methods of monetary valuation, and showed that these have insufficient institutional or public acceptability to be used for the purpose of monetary valuation in this case. This research therefore examined a new methodology for placing values on environmental impacts. i.e. Stated Preference (SP) techniques. SP determines implicit valuations by asking people to trade-off between a number of different choice situations. SP techniques are widely used throughout the transport industry for placing monetary values on factors such as journey time and ride quality. The research was successful in gaining statistically significant monetary values for Road Safety and Air Quality and respondents were able to understand the SP experiments and to trade logically between choice scenarios. However, the research identified that particular care is required when measuring and representing environmental attributes and attribute levels to respondents, as these impact on the valuations gained. Further research is also required to define the reasons for significant variation within the response data. The reasons for this variation need to be investigated further so that significant valuations can be obtained that relate to the whole population.
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    A multiple perspective approach towards the assessment and development of expert systems in manufacturing. Volume 1
    (1991-02) Holden, Peter D.; Cordey-Hayes, M.; Towriss, John
    Current approaches to technology innovation often fail because they are conceived and assessed from a single perspective or dimension. Thus, current considerations in expert systems development are characterised by a strong focus upon the technology and technical issues without a prior process of wider appraisal and technology assessment. A central theme of this study is that the business, organisational and human factors, which determine how effectively the technology will be used in practice, must be an integral part of the assessment process. The thesis describes a ‘multiple perspective approach’ to technology assessment applied to expert systems innovation in a large manufacturing organisation. This research therefore embraces detailed technical, organisational and individual perspectives of expert systems assessment and development and describes how each perspective adds new concepts, methods and tools. In practice, this has meant modelling activities and information flows in a two-site manufacturing organisation, the identification of a variety of potential areas for expert systems development, the narrowing down and selection of particular areas according to technical, organisational, business and personal criteria, and the eventual design, development, ‘operationalisation’ and evaluation of a single application. This study is placed in a wider context by complementary analyses of other manufacturing users and suppliers of expert systems. The work aims to contribute towards an understanding of expert systems innovation and to improved methodologies for technology assessment and technology transfer.
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    A resource-based view on the management of virtual web organisations
    (Cranfield University, 2001-06) Franke , Ulrich J.; Towriss, John
    For about two decades academics and practitioners have been dealing with the emerging organisational paradigm of Virtual Organisations. From a inter-organisational perspective virtual organisations are temporary configurations of independent and dispersed companies facilitated by modern information and communication technologies. One particular form of these inter-organisational virtual organisations is the virtual web organisation. The organisational concept of virtual web organisations' encompasses three interrelated organisational elements, namely the virtual web platform, virtual web management and virtual corporations. The virtual web platform is a stable company network of pre-qualified independent partner firms that have generally agreed to co-operate in virtual corporations. The virtual web platform establishes a cooperative environment and prepares the conditions for the formation and operation of dynamic virtual corporations. The management of virtual web organisations facilitates the co-operative management of the virtual web platfom and facilitates the formation and operation of virtual corporations. Based on a literature review of virtual web organisations the researcher identified a need for a better understanding of how virtual web organisations are managed. Thus, this research work aims to investigate virtual web management organisations in order to reach a better understanding that contributes to academic knowledge in the field of inter-organisational virtual organisations as well as to assist practitioners with the management of virtual web organisations. From an interpretative philosophical standpoint the researcher developed a research design that addresses the need for more knowledge about virtual web management organisations. In order to view virtual web management organisations from the inside the researcher made use of resource-based theory and developed a resource-based analytical framework. A qualitative approach was adopted and five interview-based case studies were conducted as well as one participant observation case study. Based on individual within-case analysis the researcher conducted a number of cross-case analyses. Then, the research findings were compared with and discussed in the light of existing literature and knowledge in order to improve the validity of research findings of this research work. The research findings are summarised and presented in form of a resource-based framework of virtual web management organisations. The final resource-based framework of virtual web management organisations presents all sub-competencies commonly employed by virtual web management organisations in order to perform the task of initiating and maintaining virtual web platforms, and the formation of dynamic virtual corporations. Moreover, the resource-based framework of virtual web management organisations describes the content of each sub-competence; it explains the reason and purpose of the identified common sub-competencies; it describes the temporary employment and the interrelation between them; and it provides an overview of resources and capabilities underpinning each sub-competence separately.
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    Stated preference techniques and consumer choice behaviour
    (Cranfield University, 2002-10) Abley, Jennifer; Towriss, John
    This PhD thesis examines the way in which individuals make choices during stated preference experiments (commonly referred subsets of which are called stated choice methods, conjoint analysis and trade-off analysis). Stated preference experiments ask respondents to rank, rate or choose between different product/service options, which are made up of a number of attribute mixes. The responses made by individuals within these experiments allow researchers to estimate consumer preferences. This thesis traces the historical background of stated preference experiments, from the field of utility theory and experimental economics. An understanding of this historical background explains the reliance by practitioners on the assumption that respondents make rational choices during the stated preference experiment (where all the information presented to them within the experiment is traded off in order to come to an overall preference). In light of considerable research evidence within the field of psychology that consumers do not do not conform to this economic concept of rational choice, and recent criticisms within recent stated preference literature, this thesis identifies the choice strategies employed by respondents during three stated preference experiments, where attributes were represented in different ways. Choice based stated preference experiments designed as the context for this research, measure consumers preferences for a newly developed fuel-efficient vehicle, with attributes currently unavailable in the marketplace. The experiments were presented to respondents as a series of choices between the newly developed vehicle and another currently available in the marketplace, described in terms of a number of attributes. The experiments were implemented using `think-aloud' protocol to allow the identification of respondent's choice strategies. The research successfully identifies the choice strategies employed by respondents during the stated preference experiments, and in support of recent criticisms within stated preference literature, finds significant deviations from the economic concept of rational choice. Furthermore, significant differences between the choice strategies employed by respondents are identified between the experiments where the appearance of the vehicles is represented in different ways. Using response data that is simulated to mirror the respondent choice strategies identified in each of the three stated preference experiments, the research tests the implications of these choice strategies on the estimation of consumer utility models. The research identifies significant differences between the parameter estimates derived from responses simulated assuming different choice strategy profiles. The research also identifies significant improvements in the estimated parameter values when the identified choice strategies are used in the analysis of the response data, rather than using the assumption of rational choice as an approximation. This suggests that stated prelcrence practitioners might improve model estimation by identifying the choice strategies used by respondents to inform the analysis of stated preference response data.
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    A taxonomy of highly interdependent, supply chain relationships: The use of cluster analysis
    (Mcb, 2007-01-01T00:00:00Z) Humphries, Andrew; Towriss, John; Wilding, Richard D.
    Cluster analysis provides a statistical method whereby unknown groupings of similar attributes can be identified from a mass of data and is well-known within marketing and a wide range of other disciplines. This paper seeks to describe the use of cluster analysis in an unusual setting to classify a large sample of dyadic, highly interdependent, supply chain relationships based upon the quality of their interactions. This paper aims to show how careful attention to the detail of research design and the use of combined methods leads to results that both are useful to managers and make a contribution to knowledge.
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    Understanding service management: a systematic literature review of services characteristics and classifications
    (2003-08-29) Edelman, Adrian; Towriss, John
    This dissertation presents a systematic review of the literature about the distinctive characteristics of services, often studied in terms of the similarities and differences when compared to goods, and about the classifications that scholars have developed to improve the understanding and management of services. Both topics have characterized the service management literature since its emergence. Academics have extensively used four attributes to argue that services are uniquely different from goods, as well as for arguing that the differences are not meaningful: inseparability of production and consumption, heterogeneity, intangibility, and perishability. Arguments according to different functional and theoretical perspectives and different levels of analysis are reviewed. Ultimately, it is argued that a goods/services dichotomy is irrelevant, and that research should focus on the distinctive features of a generic product/service. Management scholars have always used classifications to foster the understanding organizations at both academic and managerial levels. Most of the typologies regarding the management of services, either from a marketing or an operations management perspective, are descriptive, and only a few attempt to prescribe design and management. Classifications make use of theoretical rationales with different degrees of robustness, and utilize a large variety of dimensions to type organizations. The development of both topics has been eminently conceptual; empirical research supporting the major tenets is scarce. The systematic character of the review means that an explicit effort is made to provide transparency and traceability to the researcher's decisions and criteria. A review methodology relatively new to management research is used, and it proves to be highly valuable. The fit between the research project characteristics and the operationalization of the systematic review principles is pointed out as a contribution to the development of this methodology for management research.