Component Composition in Business and System Modelling

Bespoke development of large business systems can be couched in terms of the composition of components, which are, put simply, chunks of development work. Design, mapping a specification to an implementation, can also be expressed in terms of components: a refinement comprising an abstract component, a concrete component and a mapping between them. Similarly, system extension is the composition of an existing component, the legacy system, with a new component, the extension. This paper overviews work being done on a UK EPSRC funded research project formulating and formalizing techniques for describing, composing and performing integrity checks on components. Although the paper focuses on the specification and development of information systems, the techniques are equally applicable to the modeling and re-engineering of businesses, where no computer system may be involved

Time Series Properties of the German Monthly Production Index

The production index is an important indicator for assessing the cyclical state of the economy. Unfortunately, the monthly time series is contaminated by many noisy components like seasonal variations, calendar and vacation effects. Only part of those nuisance components are explicitly considered in the seasonal adjustment procedures used by statistical agencies. In this paper, we propose a more flexible specification for the seasonal and working day effects and introduce an indicator for the summer vacations effect. We allow for time-varying parameters and show that the resulting Unobserved Components Model delivers more reliable results for the adjusted series.production index, seasonal adjustment, working day effect, business cycles, unobserved components models

Productivity Shocks and the Business Cycle: Reconciling Recent VAR Evidence

Gali (1999) used a VAR with productivity and hours worked to argue that technology shocks are negatively correlated with labor and are unimportant for the business cycle. More recently, Beaudry and Portier (2003) studied a VAR in productivity and stock prices. Remarkably, they found that the component which has a permanent impact on productivity is almost identical to that which has no immediate impact on productivity. Moreover, either of these components explains most business cycle variation. Like Gali's results, these observations are inconsistent with early RBC models, but on the other hand they contradict Gali's claim that technology shocks are unimportant for cycles. In this paper, we study trivariate VARs in productivity, hours worked, and stock prices to see how these apparently contradictory results can be reconciled. We find one VAR specification that qualitatively and quantitatively matches the findings of Gali (so that long-run technology shocks drive hours down), and a second specification that matches the main findings of Beaudry and Portier (so that long-run technology shocks increase hours, are similar to the short-run shock to stock prices, and play a major role in generating business cycles). Surprisingly, the difference between these two specifications has nothing to do with estimating in levels or in differences, or with running VARs or VECMs, or with the ordering of variables. The only difference between the two specifications lies in which productivity variable is used: labor productivity (to generate results like Gali's) or TFP (to generate results like those of Beaudry and Portier). Both the original Beaudry and Portier estimations, as well as our findings on the productivity specification, add to the evidence that Gali's findings are not robust. Apparently the cyclical role of technology shocks is only picked up when a sufficiently cyclical productivity series is used in the estimation.Technology shocks, business cycles, news shocks

Formal specifications in component-based development

Software engineering has entered a new era, the Internet and its associated technologies require a different conceptual framework for building and understanding software solutions. Users ask to develop applications more rapidly, and software engineers need to ensamble systems from preexisting parts. Components and Components-Based Development( CBD), are the approaches that provide solutions to these arising needs. Components are the way to encapsulate existing functionality, acquire third-party solutions, and build new services to support emerging business processes. Component-based development provides a design paradigm that is well suited to the new requirements, were the traditional design and build has been replaced by select and integrate. Within this approach, the specification of components plays a crucial role. If we are working on the development of components in order to construct a library for general use, we need to start from a concrete and complete specification of what we are going to construct. If we are assembling our application from pre-existing components, we need a precise specification of the behaviour of the component in order to select it from the library.Eje: Ingeniería de Software y Base de DatosRed de Universidades con Carreras en Informática (RedUNCI

Formal specifications in component-based development

Software engineering has entered a new era, the Internet and its associated technologies require a different conceptual framework for building and understanding software solutions. Users ask to develop applications more rapidly, and software engineers need to ensamble systems from preexisting parts. Components and Components-Based Development( CBD), are the approaches that provide solutions to these arising needs. Components are the way to encapsulate existing functionality, acquire third-party solutions, and build new services to support emerging business processes. Component-based development provides a design paradigm that is well suited to the new requirements, were the traditional design and build has been replaced by select and integrate. Within this approach, the specification of components plays a crucial role. If we are working on the development of components in order to construct a library for general use, we need to start from a concrete and complete specification of what we are going to construct. If we are assembling our application from pre-existing components, we need a precise specification of the behaviour of the component in order to select it from the library.Eje: Ingeniería de Software y Base de DatosRed de Universidades con Carreras en Informática (RedUNCI

A Nonlinear Model of the Business Cycle

The usual index of leading indicators has constant weights on its components and is therefore implicitly premised on the assumption that the dynamical properties of the economy remain the same over time and across phases of the business cycle. We explore the possibility that the business cycle has phases, for example, recessions, recoveries and normal growth, each with its unique dynamics. Based on this possibility we develop a nonlinear model of the business cycle that combines a number of previous approaches. We model the state of the economy as a latent variable with a threshold autoregression structure. In addition to dependence on its own lags the latent variable is also determined by observed economic and financial variables. In turn these variables are modeled as following a nonlinear vector autoregression with regimes defined by the latent business cycle variable. A Markov Chain Monte Carlo algorithm is developed to estimate the model. Special attention is paid to specification of prior distributions given the large dimension of the model. We also investigate using the business cycle chronology of the NBER to aid in the classification of the latent variable. The two main empirical objectives of the model are to provide more accurate predictions of economic variables particularly at turning points and to describe how the dynamics differ across business cycle phasesnonlinear, business cycle, Bayesian

Hybrid business process modeling for the optimization of outcome data

Context: Declarative business processes are commonly used to describe permitted and prohibited actions in a business process. However, most current proposals of declarative languages fail in three aspects: (1) they tend to be oriented only towards the execution order of the activities; (2) the optimization is oriented only towards the minimization of the execution time or the resources used in the business process; and (3) there is an absence of capacity of execution of declarative models in commercial Business Process Management Systems. Objective: This contribution aims at taking into account these three aspects, by means of: (1) the formalization of a hybrid model oriented towards obtaining the outcome data optimization by combining a data-oriented declarative specification and a control-flow-oriented imperative specification; and (2) the automatic creation from this hybrid model to an imperative model that is executable in a standard Business Process Management System. Method: An approach, based on the definition of a hybrid business process, which uses a constraint programming paradigm, is presented. This approach enables the optimized outcome data to be obtained at runtime for the various instances. Results: A language capable of defining a hybrid model is provided, and applied to a case study. Likewise, the automatic creation of an executable constraint satisfaction problem is addressed, whose resolution allows us to attain the optimized outcome data. A brief computational study is also shown. Conclusion: A hybrid business process is defined for the specification of the relationships between declarative data and control-flow imperative components of a business process. In addition, the way in which this hybrid model automatically creates an entirely imperative model at design time is also defined. The resulting imperative model, executable in any commercial Business Process Management System, can obtain, at execution time, the optimized outcome data of the process.Ministerio de Ciencia y Tecnología TIN2009-1371

Technology and the Demand for Skill:An Analysis of Within and Between Firm Differences

We estimate the effects of technology investments on the demand for skilled workers using longitudinally integrated employer-employee data from the U.S. Census Bureau's Longitudinal Employer-Household Dynamics Program infrastructure files spanning two Economic Censuses (1992 and 1997). We estimate the distribution of human capital and its observable and unobservable components within each business for each year from 1992 to 1997. We measure technology using variables from the Annual Survey of Manufactures and the Business Expenditures Survey (services, wholesale and retail trade), both administered during the 1992 Economic Census. Static and partial adjustment models are fit. There is a strong positive empirical relationship between advanced technology and skill in a cross-sectional analysis of businesses in both sectors. The more comprehensive measures of skill reveal that advanced technology interacts with each component of skill quite differently: firms that use advanced technology are more likely to use high-ability workers, but less likely to use high-experience workers. These results hold even when we control for unobservable heterogeneity by means of a selection correction and by using a partial adjustment specification.

NETQOS policy management architecture for flexible QOS provisioning in Future Internet

This paper is focussed on the NETQOS architecture for automated QoS policy provisioning, which can be used in Future Internet scenarios by the different actors (i.e. network operators, service providers, and users) for flexible QoS configuration over combinations of mobile, fixed, sensor and broadcast networks. The NETQOS policy management architecture opens the possibility to specify QoS policies on a "business" level using ontology descriptions and policy management interfaces, which are specific to the actors. The business level policy specifications are translated by the NETQOS system into intermediate and operational QoS policies for automated QoS configuration at the managed heterogeneous network and transport entities. NETQOS allows QoS policy specification and dependency analysis considering Service Level Agreements (SLAs) between the actors, as well as automated policy provisioning and adaptation. The interaction of the NETQOS components is based on a common po licy repository. The particular focus of the paper is aimed to discuss ontology and actor oriented QoS policy specification and configuration for heterogeneous networks, as well as NETQOS QoS policy management interfaces at business level and automated translation of business QoS policies to intermediate and operational policy level