Dissertations / Theses on the topic 'Cumulative case study'

Master of Science
Department of Statistics
Perla E. Reyes Cuellar
Data with ordinal responses may be encountered in many research fields, such as social, medical, agriculture or financial sciences. In this paper, we present a case study on cumulative logit models with low frequency and mixed effects and discuss some strengths and limitations of the current methodology. Two plant pathologists requested our statistical advice to fit a cumulative logit mixed model seeking for the effect of six commercial products on the control of a seed and seedling disease in soybeans in vitro. In their attempt to estimate the model parameters using a generalized linear mixed model approach with PROC GLIMMIX, the model failed to converge. Three alternative approaches to solve the problem were examined: 1) stratifying the data searching for the random effect; 2) assuming the random effect would be small and reducing the model to a fixed model; and 3) combining the original categories of the response variable to a lower number of categories. In addition, we conducted a power analysis to evaluate the required sample size to detect treatment differences. The results of all the proposed solutions were similar. Collapsing categories for a cumulative/proportional odds model has little effect on estimation. The sample size used in the case study is enough to detect a large shift of frequencies between categories, but not for moderated changes. Moreover, we do not have enough information to estimate a random effect. Even when it is present, the results regarding the fixed factors: pathogen, evaluation day, and treatment effects are the same as the obtained by the fixed model alternatives. All six products had a significant effect in slowing the effect of the pathogen, but the effects vary between pathogen species and assessment timing or date.

Most of the significant changes on the environment have resulted from individually minor but collectively significant human actions and decisions. This kind of consequences has been defined Cumulative Effects (CE) and their systematic consideration can be attributed to the scientific basis and institutional context of Environmental Assessment (EA) theory and practice. However, although Strategic Environmental Assessment (SEA) has been largely recognised as one of the most appropriate procedure to support spatial and land use plans in managing CE; the advancement in integrating the assessment of CE into SEA practice has been often stated slow to evolve, suggesting a gap between SEA theory and practice in treating cumulative effects and confirming that further investigation on this subject is required. This research aimed to propose and apply a methodological approach to improve the consideration of CE in SEA of spatial plans, by focusing on the Italian spatial planning system and urban regions. It was developed according to the main findings and shortcomings emerging from the academic literature and the exploration of SEA practice through: an international expert survey; a systematic review of SEA documents; and a couple of real-life SEA case studies following during the research period. Among the most important were: the lack of scoping of relevant resources (or Valued Ecosystem Component); the scarce exploration of future decisions and consequences; and the requirement of a more evidence-based assessment of CE. The methodological approach was then developed for SEA of regional spatial plans, consisting of four main tasks: the selection of significant valued resources; the identification of other relevant decisions (projects, plans and policies) which together with the spatial plan could contribute to CE; the generation of land use scenarios; and the prediction of CE through indicators. Then, the methodological approach was tested in a case study selected within the peri-urban region of Milan, representing one of the most urbanised and industrialised part of Italy, with significant urban pressures on existing protected areas and remaining rural patches. Firstly, the regional green infrastructure was selected as the most important regional valued resource (or VEC); then, three important ‘future policies’ were identified (i.e. highway transportation corridor, protected areas conservation plans, and rural policies). Subsequently, a set of future land use scenarios were developed and made spatially explicit, starting from a couple of regional land use maps. Then, the regional cumulative effects on the selected valued resource (e.g. habitat fragmentation, surface runoff, etc.) were assessed against a range of future conditions through a core set of indicators, mainly quantitative and spatially explicit, simulating relevant environmental processes, such as hydrological cycle, local surface temperature, ecological connectivity. They were all selected and computed starting from land cover data, allowing the combined effects to be quantified and land use scenarios to be compared. The results mainly showed that the method provided an applicable means to, firstly, transfer policies and decisions into maps, and then, predict their combined effects on selected VEC. Moreover, it can be straightforwardly included in SEA of regional spatial plans in order to support a more evidence-based CE analysis, by adding spatial thinking to decision-makers and improving the understanding and the perception of the cumulative consequences of their “minor†decisions under uncertain future policy contexts.

Most of the significant changes on the environment have resulted from individually minor but collectively significant human actions and decisions. This kind of consequences has been defined Cumulative Effects (CE) and their systematic consideration can be attributed to the scientific basis and institutional context of Environmental Assessment (EA) theory and practice. However, although Strategic Environmental Assessment (SEA) has been largely recognised as one of the most appropriate procedure to support spatial and land use plans in managing CE; the advancement in integrating the assessment of CE into SEA practice has been often stated slow to evolve, suggesting a gap between SEA theory and practice in treating cumulative effects and confirming that further investigation on this subject is required. This research aimed to propose and apply a methodological approach to improve the consideration of CE in SEA of spatial plans, by focusing on the Italian spatial planning system and urban regions. It was developed according to the main findings and shortcomings emerging from the academic literature and the exploration of SEA practice through: an international expert survey; a systematic review of SEA documents; and a couple of real-life SEA case studies following during the research period. Among the most important were: the lack of scoping of relevant resources (or Valued Ecosystem Component); the scarce exploration of future decisions and consequences; and the requirement of a more evidence-based assessment of CE. The methodological approach was then developed for SEA of regional spatial plans, consisting of four main tasks: the selection of significant valued resources; the identification of other relevant decisions (projects, plans and policies) which together with the spatial plan could contribute to CE; the generation of land use scenarios; and the prediction of CE through indicators. Then, the methodological approach was tested in a case study selected within the peri-urban region of Milan, representing one of the most urbanised and industrialised part of Italy, with significant urban pressures on existing protected areas and remaining rural patches. Firstly, the regional green infrastructure was selected as the most important regional valued resource (or VEC); then, three important ‘future policies’ were identified (i.e. highway transportation corridor, protected areas conservation plans, and rural policies). Subsequently, a set of future land use scenarios were developed and made spatially explicit, starting from a couple of regional land use maps. Then, the regional cumulative effects on the selected valued resource (e.g. habitat fragmentation, surface runoff, etc.) were assessed against a range of future conditions through a core set of indicators, mainly quantitative and spatially explicit, simulating relevant environmental processes, such as hydrological cycle, local surface temperature, ecological connectivity. They were all selected and computed starting from land cover data, allowing the combined effects to be quantified and land use scenarios to be compared. The results mainly showed that the method provided an applicable means to, firstly, transfer policies and decisions into maps, and then, predict their combined effects on selected VEC. Moreover, it can be straightforwardly included in SEA of regional spatial plans in order to support a more evidence-based CE analysis, by adding spatial thinking to decision-makers and improving the understanding and the perception of the cumulative consequences of their “minor” decisions under uncertain future policy contexts.

The main objective of this Bachelor’s thesis is to investigate and deliver the results of environmental impacts of two different designs of crane truck frames. The aim is to investigate if additional new design of crane truck frames, with less energy and transportation during manufacturing of the crane truck, can improve energy efficiency of crane trucks throughout their lifecycle. Case study object for this report is Vemservice in Vemdalen, Sweden. As basis for the report the The Life Cycle Analysis ISO 14040 and ISO 14044 are used in this report in order to evaluate and compare the environmental impacts related to the lifecycle of new and old designs of 92 tonmeter crane truck frames from cradle to grave. The data was mainly collected and calculated by using the SimaPro software 8.0.5 which is based on the Ecoinvent 3 database. This study mainly analyzes environmental impacts such as GWP (Global Warming Potential), CED (Cumulative Energy Demand) and ReCiPe environmental impacts. The results showed that although new design frame has less transportation and energy demand during the manufacturing phase of the crane truck, the overall life cycle of the new design crane truck frame has higher environmental impacts than the existing old design of the crane truck frame. This is due to that the new design frame is 213kg heavier than the old design frame, which the crane truck is carrying during its using period. This study also investigated whether the new design frame, with stronger steel (Ecoupgraded steel) and a reduction of 15% of the total weight of frame, has a lower environmental impact in the life cycle of the EcoUpgraded steel frame compared to the current new design and old design frames life cycle.

2018-06-29

Les initiatives féministes s’organisent pour générer des transformations sociales, maillant différents espaces de cause féministes. Ces initiatives s’apparentent à des processus de commoning multi-acteurs. Nous proposons de développer une approche symbiotique pour analyser ces phénomènes, inspirée de la symbiose industrielle et de l'économie symbiotique. L'étude repose sur quatre cas d'initiatives féministes, analysés qualitativement de manière cumulative pour développer une modélisation de la symbiose féministe. Cette modélisation constitue une théorisation de la symbiose féministe, s’appuyant sur des composants, des mécanismes et des propriétés. Cela permet de définir la symbiose féministe comme une modalité de commoning inter-organisationnel fondée sur une diversité d’acteurs entretenant des relations mutuellement avantageuses au profit d’un commun féministe sur lequel ils s’accordent et qui présente des bénéficiaires (in)direct•e•s
Feminist initiatives are organizing to generate social transformations, weaving together various feminist cause spaces. These initiatives resemble multi-actor commoning processes. We propose to develop a symbiotic approach to analyze these phenomena, inspired by industrial symbiosis and symbiotic economics. The study is based on four cases of feminist initiatives and is analyzed qualitatively in a cumulative manner to develop a modeling of feminist symbiosis. This modeling constitutes a theorization of feminist symbiosis, relying on components, mechanisms, and properties. This allows us to define feminist symbiosis as a modality of inter-organizational commoning based on a diversity of actors engaging in mutually beneficial relationships for the benefit of a feminist common that they agree upon, which has (in)direct beneficiaries

The information service sector e.g. utilities, telecommunications and banking has grown rapidly in recent years and is a significant contributor to the Gross Domestic Product (GDP) of the world’s leading economies. Though, the information service sector has grown significantly, there have been relatively few attempts by researchers to explore this sector. The lack of research in this sector has motivated my PhD research that aims to explore the pre-established relationships between dependability, quality and customer satisfaction (RQ1) within the context of information service sector. Literature looking at the interrelationship between the dependability and quality (RQ2a), and their further impact on customer satisfaction (RQ2b) is also limited. With the understanding that Business to Business (B2B) and Business to Customer (B2C) businesses are different, exploring these relationships in these two different types of information firms will further add to existing literature. This thesis also attempts to investigate the relative significance of dependability and quality in both B2B and B2C information service firms (RQ3a and RQ3b). To address these issues, this PhD research follows a theory testing approach and uses multiple case studies to address the research questions. In total five cases from different B2B and B2C information service firms are being investigated. To explore the causality, the time series data set of over 24 to 60 months time and the ‘Path Analysis’ method has been used. For the generalization of the findings, Cumulative Meta Analysis method has been applied. The findings of this thesis indicate that dependability significantly affects customer satisfaction and an interrelationship exists between dependability and quality that further impacts customer satisfaction. The findings from B2C cases challenges the traditional priority afforded to relational aspect of quality by showing that dependability is the key driver of customer satisfaction. However, B2B cases findings shows that both dependability and quality are key drivers of customer satisfaction. Therefore, the findings of this thesis add considerably to literature in B2B and B2C information services context.

Researchers in various business disciplines use the event study methodology to assess the market value of firms through capital market reaction to news in the public media about the firm's activities. Capital market reaction is assessed based on cumulative abnormal return (sum of abnormal returns over the event window). In this study, the event study methodology is used to assess the impact that two important information technology activities, Internet security breach and ecommerce initiative, have on the market value of firms. While prior research on the relationship between these business activities and cumulative abnormal return involved the use of regression analysis, in this study, we use decision tree induction and regression.For the Internet security breach study, we use negative cumulative abnormal return as a surrogate for damage to the breached firm. In contrast to what has been reported in the research literature, our results suggest that the relationship between cumulative abnormal return and the independent variables for both the Internet security breach and ecommerce initiative studies is complex, often involving conditional interactions between the independent variables. We report that the incomplete contract theory is unable to effectively explain the relationship between cumulative abnormal return and the organizational variables. Other ecommerce theories provide support to the findings from our analysis. We show that both attack and firm characteristics are determinants of damage to breached firms.Our results revealed that the use of decision tree induction presents additional insight to that provided by regression models. We illustrate that there is value in using data mining techniques to study the market value of e-commerce initiative and Internet security breach and that this approach has applicability in other domains and that Decision Tree can enhance the event study methodology.We demonstrate that Decision Tree induction can be used for both theory building and theory testing. We specifically employ Decision Tree induction to test and enhance ecommerce theories and develop a theoretical model for cumulative abnormal return and ecommerce. We also present theoretical models for Internet security breach and damage to the breached firm. These models can be used by decision makers in Internet security and ecommerce investments strategic formulations and implementations.

ABSTRACT Purpose: The purpose of this study was to examine the relationship between self-reported sedentary time (ST) and the cumulative risk of preserved ejection fraction heart failure (HFpEF) and reduced ejection fraction heart failure (HFrEF) using a diverse cohort of U.S. adults 45-84 years of age. Methods: Using data from the Multi-Ethnic Study of Atherosclerosis (MESA), we identified 6,814 subjects (52.9% female). All were free of baseline cardiovascular disease. Cox regression was used to calculate the hazard ratios (HR) associated with baseline ST and risk of overall heart failure (HF), HFpEF, and HFrEF. Weekly self-reported ST was dichotomized based on the 75th percentile (1,890 min/wk). Results: During an average of 11.2 years of follow-up there were 178 first incident HF diagnoses; 74 HFpEF, 69 HFrEF and 35 with unknown EF. Baseline ST >1,890 min/wk was significantly associated with an increased risk of HFpEF (HR [95% CI]; 1.87 [1.13 – 3.09], p= 0.01), but not HFrEF (HR [95% CI]; 1.30 [0.78 – 2.15], p= 0.32). The relationship with HFpEF remained significant in separate fully adjusted models including either waist circumference (HR [95% CI]; 2.16 [1.23 – 3.78], p < 0.01) or body mass index (HR [95% CI]; 2.17 [1.24 – 3.80], p < 0.01). Additionally, every 60 minute increase in weekly ST was associated with a significant 3% increased risk of HFpEF (HR [95% CI]; 1.03 [1.01 – 1.05], p < 0.01). Conclusions: Sedentary time > 1,890 min/wk (~4.5 h/d) is a significant independent predictor of HFpEF, but not HFrEF.

The cumulative impact of multiple stressors on the environment over time and space has been acknowledged as a key process in the ongoing loss of habitat and biodiversity and as a driver of landscape change. Regulatory approaches that address environmental impacts only at the level of the individual project footprint may facilitate significant environmental impacts through the cumulative effects of those projects. Such approaches are unlikely to ensure that current and future development of natural resources is sustainable. The catchment spatial scale and the regulatory processes that govern three key activities within it - farm dams, forest practices and water abstraction - form the basis for an examination of cumulative effects in Tasmania. International and Commonwealth regulatory approaches to cumulative effects, key concepts and methodologies are examined through a literature review. The potential cumulative impact of farm dams, forest practices and water abstraction on the natural flow regime, freshwater ecological processes and biota is established through the relevant literature. A case study of the Great Forester — Brid catchment in north east Tasmania is used to determine the potential for these impacts to occur in Tasmanian catchments. The results of this study show that there are measurable cumulative impacts on the natural flow regime, connectivity and special natural values within the catchment. Relevant legislation, policies and processes are examined to establish an understanding of how cumulative effects are addressed in Tasmania for these activities. Cumulative impacts of these activities are not adequately addressed in the current legislative and policy environment in Tasmania. An explicit legislative requirement for cumulative effects needs to be considered. In addition a pro-active, regional framework to manage and assess cumulative effects, incorporating integrated catchment management, is a fundamental requirement for the sustainable use of natural resources in Tasmania.

The construction and operation of hydroelectric projects consist of multiple activities in a single watershed, which can generate significant impacts on the surrounding biophysical environment and on the health and well-being of local communities. The impacts of those activities may be insignificant individually, yet together may have an important cumulative effect. The impacts of hydroelectric development on human health and well-being have been widely documented. Current practices of cumulative effects assessment (CEA), however, as conducted under project-based environmental assessment (EA), often fail to address the deeper issues of human health and social well-being. This thesis was developed to examine how health effects, including cumulative health effects, are considered within regulatory EA practices in the hydroelectric sector in Manitoba. This was achieved by reviewing the EAs of three recent hydroelectric projects –Wuskwatim Generating Station, Bipole III Transmission Project, and Keeyask Hydroelectric Generating Station – located in the Nelson River watershed in northern Manitoba. Results indicate that the consideration of human health issues in EA has gradually improved over time; however, the assessment of health impacts was invariably limited to physical health components and often lacked due consideration of broader social health issues. The inadequacy of the practice of health impact assessment (HIA) was also evident by the lack of health-related indicators and the poor consistency in the use of indicators across projects and over time for measuring and predicting changes in the health conditions of the communities due to project development. An in-depth analysis regarding the assessment of cumulative health effects was carried out in the CEA of the most recent hydroelectric development – the Keeyask project. The findings show that cumulative health effects were not adequately considered in each of the basic components of CEA – scoping, retrospective analysis, prospective analysis, and management measures. Improving the consideration of health in EA requires paying more attention to broader range of health determinants, including both biophysical and social determinants and their interconnectedness in EA. Moreover, there is a need to improve greater consistency in the use of health indicators across projects and over time. It can be assisted by developing standardized terms of reference (ToR) for project proponents to ensure the consideration and monitoring of those indicators used for development projects built within the same geographic region and affecting the same communities and environments. Approaching cumulative health effects in a more regional and strategic framework of CEA, beyond the scale of individual projects, is likely to provide the best mechanism to understand and monitor the cumulative impacts of project development on the health and well-being of the affected communities.

Protecting and managing Canadian water resources in the face of growing cumulative effects and non-point source pollution from development (industrial, agricultural, and urban), depends on defensible, scientifically founded, watershed assessments. The objectives of this research were to broadly characterize the spatial and temporal patterns in water quality (total phosphorus and total nitrogen concentration, export and yield) across a land use disturbance gradient (forest, agriculture, urban) to elucidate pressures on water quality from specific landscape regions within the three headwater sub-basins of the Oldman River basin. While the water quality in the Oldman basin, remains fairly pristine, important spatial differences in nutrient production were evident between the upstream (predominantly forested) and the downstream (mixed agricultural/forested) reaches within the sub-basins. Using the pressure state response model as a framework to link landscapes to observed water quality, it was also found that phosphorus contamination may be an issue in the headwaters.
Water and Land Resources

碩士
國立臺北大學
都市計劃研究所
92
[ABSTRACT] Taiwan has become a developed country through the past hundreds of years and had made what we call ‘economical miracle’. However, there are more environment problems growing while life on this island is getting more plentiful. People would easily ignore the limitation of the environmental resources during the progress of developing; therefore, under the long-term unrestricted over-exploitation, the influence to the environment grows. Once the amount of the influencing factors is over the threshold of the environmental carrying capacity, it would cause some serious problems to the nature. In the past decades, the authority concerns did the environmental management regarding the Environmental Impact Assessment (EIA), but it only focuses on individual projects, not on the interactive Cumulative Environmental Effects or on examining the possible relationship between them, for example, the affection to the tolerance of the environment. In this case, the truly important issues can not be projected, and the effect of environmental manipulation or management can not be elaborated. This study aims at the cumulative environmental effects from the man-mad e substantial development to the local environment, focusing on the development of Taoyuan Prefecture, trying to probe the possible cumulative effects under the expansion of the time-space domain with a dynamic view, in order to survey its development policy and related projects under the management of EIA and also clarify the existence and importance of cumulative effects. Main parts of the thesis are clarifying basic thoughts, discussing the relationships and analysis, and exemplifying real examples. The results of this study show the following five points. First, the logic the cumulative effects are rather reticulate and complicated, but not a unidirectional and simple research method and environmental managing system could control and clarify. Second, the local environmental effects emphasize on the cumulative effects of all the related individual cases within the region. An individual development would not sufficiently represent the effects to the whole environment. Third, the possible status of the local cumulative environment effects in the exploitation of the land is not only an EIA concerning the cumulative effects but also with a function of controlling and managing the quality of regional environment. Fourth, local cumulative environmental effects are directly related to the long-term environmental change depending on the individual development of each region. Fifth, the environmental management of the case in this study is very different from the contention of cumulative environmental effects. Obviously, the present development permission system lacks of respecting the cumulative environmental effects.

Contexte. Les études cas-témoins sont très fréquemment utilisées par les épidémiologistes pour évaluer l’impact de certaines expositions sur une maladie particulière. Ces expositions peuvent être représentées par plusieurs variables dépendant du temps, et de nouvelles méthodes sont nécessaires pour estimer de manière précise leurs effets. En effet, la régression logistique qui est la méthode conventionnelle pour analyser les données cas-témoins ne tient pas directement compte des changements de valeurs des covariables au cours du temps. Par opposition, les méthodes d’analyse des données de survie telles que le modèle de Cox à risques instantanés proportionnels peuvent directement incorporer des covariables dépendant du temps représentant les histoires individuelles d’exposition. Cependant, cela nécessite de manipuler les ensembles de sujets à risque avec précaution à cause du sur-échantillonnage des cas, en comparaison avec les témoins, dans les études cas-témoins. Comme montré dans une étude de simulation précédente, la définition optimale des ensembles de sujets à risque pour l’analyse des données cas-témoins reste encore à être élucidée, et à être étudiée dans le cas des variables dépendant du temps. Objectif: L’objectif général est de proposer et d’étudier de nouvelles versions du modèle de Cox pour estimer l’impact d’expositions variant dans le temps dans les études cas-témoins, et de les appliquer à des données réelles cas-témoins sur le cancer du poumon et le tabac. Méthodes. J’ai identifié de nouvelles définitions d’ensemble de sujets à risque, potentiellement optimales (le Weighted Cox model and le Simple weighted Cox model), dans lesquelles différentes pondérations ont été affectées aux cas et aux témoins, afin de refléter les proportions de cas et de non cas dans la population source. Les propriétés des estimateurs des effets d’exposition ont été étudiées par simulation. Différents aspects d’exposition ont été générés (intensité, durée, valeur cumulée d’exposition). Les données cas-témoins générées ont été ensuite analysées avec différentes versions du modèle de Cox, incluant les définitions anciennes et nouvelles des ensembles de sujets à risque, ainsi qu’avec la régression logistique conventionnelle, à des fins de comparaison. Les différents modèles de régression ont ensuite été appliqués sur des données réelles cas-témoins sur le cancer du poumon. Les estimations des effets de différentes variables de tabac, obtenues avec les différentes méthodes, ont été comparées entre elles, et comparées aux résultats des simulations. Résultats. Les résultats des simulations montrent que les estimations des nouveaux modèles de Cox pondérés proposés, surtout celles du Weighted Cox model, sont bien moins biaisées que les estimations des modèles de Cox existants qui incluent ou excluent simplement les futurs cas de chaque ensemble de sujets à risque. De plus, les estimations du Weighted Cox model étaient légèrement, mais systématiquement, moins biaisées que celles de la régression logistique. L’application aux données réelles montre de plus grandes différences entre les estimations de la régression logistique et des modèles de Cox pondérés, pour quelques variables de tabac dépendant du temps. Conclusions. Les résultats suggèrent que le nouveau modèle de Cox pondéré propose pourrait être une alternative intéressante au modèle de régression logistique, pour estimer les effets d’expositions dépendant du temps dans les études cas-témoins
Background: Case-control studies are very often used by epidemiologists to assess the impact of specific exposure(s) on a particular disease. These exposures may be represented by several time-dependent covariates and new methods are needed to accurately estimate their effects. Indeed, conventional logistic regression, which is the standard method to analyze case-control data, does not directly account for changes in covariate values over time. By contrast, survival analytic methods such as the Cox proportional hazards model can directly incorporate time-dependent covariates representing the individual entire exposure histories. However, it requires some careful manipulation of risk sets because of the over-sampling of cases, compared to controls, in case-control studies. As shown in a preliminary simulation study, the optimal definition of risk sets for the analysis of case-control data remains unclear and has to be investigated in the case of time-dependent variables. Objective: The overall objective is to propose and to investigate new versions of the Cox model for assessing the impact of time-dependent exposures in case-control studies, and to apply them to a real case-control dataset on lung cancer and smoking. Methods: I identified some potential new risk sets definitions (the weighted Cox model and the simple weighted Cox model), in which different weights were given to cases and controls, in order to reflect the proportions of cases and non cases in the source population. The properties of the estimates of the exposure effects that result from these new risk sets definitions were investigated through a simulation study. Various aspects of exposure were generated (intensity, duration, cumulative exposure value). The simulated case-control data were then analysed using different versions of Cox’s models corresponding to existing and new definitions of risk sets, as well as with standard logistic regression, for comparison purpose. The different regression models were then applied to real case-control data on lung cancer. The estimates of the effects of different smoking variables, obtained with the different methods, were compared to each other, as well as to simulation results. Results: The simulation results show that the estimates from the new proposed weighted Cox models, especially those from the weighted Cox model, are much less biased than the estimates from the existing Cox models that simply include or exclude future cases. In addition, the weighted Cox model was slightly, but systematically, less biased than logistic regression. The real life application shows some greater discrepancies between the estimates of the proposed Cox models and logistic regression, for some smoking time-dependent covariates. Conclusions: The results suggest that the new proposed weighted Cox models could be an interesting alternative to logistic regression for estimating the effects of time-dependent exposures in case-control studies.

碩士
國立雲林科技大學
資訊管理系碩士班
92
To face and to participate in the global competition of the 21st century, enterprise must have luxury human resources and information technology. Nowadays, most industries are finding the ways to discover their potential through the information technology. Hence, discover the enterprise potential has been the goal for every industry. Today, the Enterprise Information Portal (EIP) plays an important role on the usage of the information and knowledge. According to the strategy target established by enterprise or department and information technology designs the exclusive EIP. This system is involved not only integration of inner enterprise resource, but also chain values of customers, employee and collaborative companies. The aim of this study explores intellectual capital process model, balanced score card (BSC) and the EIP information strategy, to help the enterprise accumulate intelligence capital in order to increase the enterprise value. Therefore, the EIP establishment of this research is based on each strategy of all departments, Key Success Factors (KSF) and Key Performance Indicators (KPI) made by managers, etc. Through the operation, we will invite the participant of each parties to join questionnaire in order to know how the information strategy may benefit the enterprise intelligence capital (IC). Resultly, although enterprises have EIP, but we still must adjust the system function and reevaluate lead-indicators and fall-behind-indicators gradually in order to gain the strategy target step by step. This also shows up the importance of comprehensive analysis and evaluation in KPI. The benefit on three perspectives of IC is construction capital, relationship capital and human capitals on order.