A Latent Variable Approach to Multivariate Quantitative Trait Loci

A novel approach based on latent variable modelling is presented for the analysis of multivariate quantitative and qualitative trait loci. The approach is general in the sense that it enables the joint analysis of many kinds of quantitative and qualitative traits (including count data and censored traits) in a single modelling framework. In the framework, the observations are modelled as functions of latent variables, which are then affected by quantitative trait loci. Separating the analysis in this way means that measurement errors in the phenotypic observations can be included easily in the model, providing robust inferences. The performance of the method is illustrated using two real multivariate datasets, from barley and Scots pine

Analysing Process Models Quantitatively

Over the years, there has been much interest in modelling processes. Processes include those associated with the development of software and those business processes that make use of software systems. Recent research in Systems Engineering for Business Process Change highlights the importance of modelling business processes in order to evolve and maintain the legacy systems that support those processes. Business processes are typically described with static (diagrammatic) models. This paper illustrates how quantitative techniques can facilitate analysis of such models. This is illustrated with reference to the process modelling notation Role Activity Diagrams (RADs). An example process, taken from an investigation of the bidding process of a large telecommunications systems supplier, is used to show how a quantitative approach can be used to highlight features in RADs that are useful to the process modeller. We show how simple measures reveal high levels of role coupling and discrepancies between different perspectives. Since the models are non-trivial — there are 101 roles and almost 300 activities — we argue that quantitative analysis can be a useful adjunct for the modeller

Modelling, reduction and analysis of Markov automata (extended version)

Markov automata (MA) constitute an expressive continuous-time compositional modelling formalism. They appear as semantic backbones for engineering frameworks including dynamic fault trees, Generalised Stochastic Petri Nets, and AADL. Their expressive power has thus far precluded them from effective analysis by probabilistic (and statistical) model checkers, stochastic game solvers, or analysis tools for Petri net-like formalisms. This paper presents the foundations and underlying algorithms for efficient MA modelling, reduction using static analysis, and most importantly, quantitative analysis. We also discuss implementation pragmatics of supporting tools and present several case studies demonstrating feasibility and usability of MA in practice

Azormod dynamic general equilibrium model for Azores

The main objective of this paper is to present a multi-sectoral, multi-regional dynamic modelling platform of the Azores economy integrated within the European and global context. The platform will have the highest capabilities of analysis and forecasting in Azores for problems related to structural sectoral and regional issues, agriculture, labour markets, public finance, trade, EU funds, regional development, environment, and energy. The modelling platform is intended to act as an analytical and quantitative support for policy-making.info:eu-repo/semantics/publishedVersio

The integrated use of enterprise and system dynamics modelling techniques in support of business decisions

Enterprise modelling techniques support business process re-engineering by capturing existing processes and based on perceived outputs, support the design of future process models capable of meeting enterprise requirements. System dynamics modelling tools on the other hand are used extensively for policy analysis and modelling aspects of dynamics which impact on businesses. In this paper, the use of enterprise and system dynamics modelling techniques has been integrated to facilitate qualitative and quantitative reasoning about the structures and behaviours of processes and resource systems used by a Manufacturing Enterprise during the production of composite bearings. The case study testing reported has led to the specification of a new modelling methodology for analysing and managing dynamics and complexities in production systems. This methodology is based on a systematic transformation process, which synergises the use of a selection of public domain enterprise modelling, causal loop and continuous simulationmodelling techniques. The success of the modelling process defined relies on the creation of useful CIMOSA process models which are then converted to causal loops. The causal loop models are then structured and translated to equivalent dynamic simulation models using the proprietary continuous simulation modelling tool iThink

EVALUATION OF THE 2006/7 AGRICULTURAL INPUT SUBSIDY PROGRAMME, MALAWI. FINAL REPORT

This report evaluates the 2006/7 Malawi Government Agricultural Input Subsidy Programme (AISP). The main objective of the evaluation is to assess the impact and implementation of the AISP in order to provide lessons for future interventions in growth and social protection. The evaluation combined qualitative and quantitative methods of data collection and analysis. Quantitative data were collected through a national survey in 2007 of 2,491 households who were previously interviewed in the 2004/05 Integrated Household Survey, a survey of retail shops selling inputs in six districts and data on stocks and sales from manufacturers, large-scale importers and dealers of fertilizers and seeds. The quantitative data was triangulated by qualitative data from focus group discussions with smallholder farmers in 12 districts, and key informant interviews with government staff, input distributors and beneficiary and non-beneficiary households. The analysis is based on descriptive statistics, econometric modelling and livelihood and rural economy modelling. An Interim Report in March 2007 provides fuller details of the implementation of the programme.Agribusiness, Agricultural and Food Policy, Community/Rural/Urban Development, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Productivity Analysis,

QUANTIFYING THE HETEROGENEITY OF ABATEMENT COSTS UNDER CLIMATIC AND ENVIRONMENTAL REGULATION CHANGES: AN INTEGRATED MODELLING APPROACH

We present here preliminary results of an integrated modelling approach combining a crop model (STICS) and an economic model (AROPAj) of European agricultural supply. This modelling framework is designed to perform quantitative analysis, regarding climate change impacts on agriculture and more generally the interactions between soils, land use, agriculture and climate integrating physical and economical elements (data, process, models). It explicitly integrates an agricultural diversity dimension with regards to economic set of choices and soil climate spatial variability. First results are given in term of quantitative analysis combining optimal land allocation (economic optimality) and “dose-response” functions related to a large set of crops in Europe, at the farm group level, covering part of the European Union (EU15). They indicate that accounting for economical and spatial variability may impact both regional aggregated scales results.Crop Production/Industries, Environmental Economics and Policy, International Relations/Trade, Land Economics/Use, Resource /Energy Economics and Policy,

BS-ISO helical gear fatigue life estimation and wear quantitative features analysis

Original article can be found at: http://www3.interscience.wiley.com/ Copyright Blackwell Publishing. DOI: 10.1111/j.1475-1305.2008.00457.xLack of representative theoretical models for gear wear causes difficulties in their useful lifetime prediction. Critical operating parameters, such as loading and lubrication, affect the wear process in a very complex manner and lead the theoretical modelling to an imperfect zone of assumptions. Complexities in gear wear mathematical modelling allow the researchers to use approximations for useful lifetime calculations. On the basis of modelling approximations and assumptions, organizations, such as American Gear Manufacturers' Association (AGMA) and British Standards (BS), provide gear useful lifetime formulations. In these formulations, the useful lifetime values are estimated by means of experimentation that is controlled with known gear operating conditions and physical dimensions. However, for useful lifetime estimation and validation, these standards have not considered any experimental approach that represents the actual gear wear. In this paper, an effort is made to validate the competency of standard's gear useful lifetime formulation. For this purpose, an approach that is able to provide an idea about actual gear wear is used. During the effort, BS-ISO 6336-2 standard formulation is used for helical gear useful lifetime estimation under linear pitting fatigue conditions. The used formulation is validated by using wear quantitative feature analysis that is able to provide actual gear wear quantitative trends. The obtained wear quantitative trends fairly validate the lifetime estimation of BS-ISO 6336-2 standard.Peer reviewe

Characterization of production in different branches of production in different branches spanish industrial activity, by means of time series analysis.

This work presents a quantitative study of the evolution of spanish industrial activity, measured by the indices of industrial production, by means of Time Series analysis. Univariate ARIMA models with intervention analysis for all the series of these indices have been constructed. The use of Univariate Time Series models to characterise economic phenomena is justified and the type of characterisation made for each industrial branch is described. The procedures for automatic modelling of series are presented. Then the characteristics of the Spanish industrial branches are shown. These results are collected in a diskette for use of researchers.ARIMA model; Intervention analysis; Univariate model; Industrial production; automatic modelling;