Web Services: A Process Algebra Approach

It is now well-admitted that formal methods are helpful for many issues raised in the Web service area. In this paper we present a framework for the design and verification of WSs using process algebras and their tools. We define a two-way mapping between abstract specifications written using these calculi and executable Web services written in BPEL4WS. Several choices are available: design and correct errors in BPEL4WS, using process algebra verification tools, or design and correct in process algebra and automatically obtaining the corresponding BPEL4WS code. The approaches can be combined. Process algebra are not useful only for temporal logic verification: we remark the use of simulation/bisimulation both for verification and for the hierarchical refinement design method. It is worth noting that our approach allows the use of any process algebra depending on the needs of the user at different levels (expressiveness, existence of reasoning tools, user expertise)

Service composition in stochastic settings

With the growth of the Internet-of-Things and online Web services, more services with more capabilities are available to us. The ability to generate new, more useful services from existing ones has been the focus of much research for over a decade. The goal is, given a specification of the behavior of the target service, to build a controller, known as an orchestrator, that uses existing services to satisfy the requirements of the target service. The model of services and requirements used in most work is that of a finite state machine. This implies that the specification can either be satisfied or not, with no middle ground. This is a major drawback, since often an exact solution cannot be obtained. In this paper we study a simple stochastic model for service composition: we annotate the tar- get service with probabilities describing the likelihood of requesting each action in a state, and rewards for being able to execute actions. We show how to solve the resulting problem by solving a certain Markov Decision Process (MDP) derived from the service and requirement specifications. The solution to this MDP induces an orchestrator that coincides with the exact solution if a composition exists. Otherwise it provides an approximate solution that maximizes the expected sum of values of user requests that can be serviced. The model studied although simple shades light on composition in stochastic settings and indeed we discuss several possible extensions

Foreign direct investment and integration into global production and distribution networks : the case of Poland

Not until the end of the twentieth century, the"second globalization,"has the ratio of trade to Gross Domestic Product been comparable to that during the first globalization, which took place at the end of the nineteenth century and was interrupted by World War I. Technological progress has increased the importance of the international division of labor and of global production and distribution networks. Multinational corporatios have been a driving force behind these developments. As a transition economy, Poland provides an interesting case for study, as its sudden opening to foreign investment after a long period of isolation allows the process of integratio into global networks to be studies more clearly. Using Poland as a case study, the authors study multinational corporatios'role in integrating a host country into the increasingly international division of labor. They provide evidence that inflows of foreign direct investment are increasing Poland's participation in global production and distribution networks. They conclude that because of the large volume of foreign direct investment inflows expected in Poland in the near future, Poland's exports--driven by fragmented production production--will continue to expand at even faster rates than observed there recently.Agribusiness&Markets,Economic Theory&Research,Environmental Economics&Policies,Trade Policy,Payment Systems&Infrastructure,Economic Theory&Research,Environmental Economics&Policies,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Trade Policy,Consumption

A Framework for Dynamic Web Services Composition

Dynamic composition of web services is a promising approach and at the same time a challenging research area for the dissemination of service-oriented applications. It is widely recognised that service semantics is a key element for the dynamic composition of Web services, since it allows the unambiguous descriptions of a service's capabilities and parameters. This paper introduces a framework for performing dynamic service composition by exploiting the semantic matchmaking between service parameters (i.e., outputs and inputs) to enable their interconnection and interaction. The basic assumption of the framework is that matchmaking enables finding semantic compatibilities among independently defined service descriptions. We also developed a composition algorithm that follows a semantic graph-based approach, in which a graph represents service compositions and the nodes of this graph represent semantic connections between services. Moreover, functional and non-functional properties of services are considered, to enable the computation of relevant and most suitable service compositions for some service request. The suggested end-to-end functional level service composition framework is illustrated with a realistic application scenario from the IST SPICE project

Drawing OWL 2 ontologies with Eddy the editor

In this paper we introduce Eddy, a new open-source tool for the graphical editing of OWL~2 ontologies. Eddy is specifically designed for creating ontologies in Graphol, a completely visual ontology language that is equivalent to OWL~2. Thus, in Eddy ontologies are easily drawn as diagrams, rather than written as sets of formulas, as commonly happens in popular ontology design and engineering environments. This makes Eddy particularly suited for usage by people who are more familiar with diagramatic languages for conceptual modeling rather than with typical ontology formalisms, as is often required in non-academic and industrial contexts. Eddy provides intuitive functionalities for specifying Graphol diagrams, guarantees their syntactic correctness, and allows for exporting them in standard OWL 2 syntax. A user evaluation study we conducted shows that Eddy is perceived as an easy and intuitive tool for ontology specification

Structural adjustment in the 1980s : Kenya

Did the World Bank's policy-based lending to Kenya in the 1980s allow Kenya to undertake adjustment, or to postpone it? The answer is mixed, says the author. Success was greatest in trade liberalization (and exchange rate depreciation), and to a lesser extent in export development -- and these reforms would probably not have occurred without steady Bank lending. But one could argue that budget support through funds from the International Development Association may have helped Kenya postpone critical public sector reform -- in the civil service and social sectors and in divestiture of parastatals (including the National Cereals and Produce Board). Was aid to Kenya (including the Bank's) overgenerous? The author concludes that, based on reform behavior and performance, Kenya may deserve less aid than Ghana (Africa's best performer) but it does not exhibit the same aid dependency as other donor favorites in the region. But its public investment program did a poor job in ranking priorities, and growing reliance on grants and counterpart funds undoubtedly contributed to more consumption spending by government, particularly on the civil service and parastatals. Implementation of structural adjustments in Kenya was often lethargic and sometimes even contrary to stated policies, says the author. And despite a fairly stable political climate, commitment to the adjustment program was patchy and intermittent. Reforms ostensibly undertaken were in fact not always implemented. In principle, for example, an auction market for government paper was created, but in practice financial institutions typically undertook up most of that paper"by arrangement."And restrictions on movement of maize were removed but reimposed. Moreover, the design of the structural adjustment loans appears, in retrospect, to have been faulty. Too many conditions -- too general, and based on dated sectoral information -- were attached to each loan, in part because of political considerations. And the Bank released credit tranches when conditions were met in letter but not in spirit. The adjustment program benefited in the second half of the 1980s from lessons learned in the first half of the decade, particularly concerning trade liberalization and export development. But the design and dimensions of reform in the agricultural sector were too limited to achieve significant restructuring of the sector, and political interests effectively sabotaged the program. The second attempt at adjustment was also undermined by increasing financial laxity. The experience in Kenya underlines the difficulty of implementing structural adjustment under either financial laxity or extreme financial stringency. Note, too, that many things have changed in Kenya since this study was completed in the early 1990s.Environmental Economics&Policies,Economic Theory&Research,Economic Stabilization,Banks&Banking Reform,National Governance

Hydrological controls on nutrient exportation from old-growth evergreen rainforests and Eucalyptus nitens plantation in headwater catchments at Southern Chile

Soil cover disturbances have a direct effect on biogeochemistry, potentially enhancing nutrient loss, land degradation and associated changes in ecosystem services and livelihood support. The objective of this study was to assess how canopy affected throughfall chemistry and how hydrology affected stream nutrient load responses in two watersheds dominated by native old-growth evergreen rainforest (NF) and exotic plantation of Eucalyptus nitens (EP), located at the Coastal mountain range of southern Chile (40˚S). We measured nitrogen (NO3-N, NH4-N, Organic-N, Total-N) and total phosphorus (Total-P) at catchment discharge, and δ18O in throughfall precipitation and stream discharge in both catchments, in order to separate throughfall (or new water) contributions during storm events. It was hypothesized that all nutrients showed an increase in concentration as discharge increased (or enhanced hydrological access), in EP; but not in NF. Our results indicated that Organic-N, Total-N and Total-P concentrations were positively related to discharge. However, 3 NO− -N showed a negative correlation with catchment discharge

The macroeconomics of adjustment in sub-Saharan African countries : results and lessons

Despite the satisfactory performance of several intensely adjusting sub-Saharan African countries - and successful results in agriculture and food production - the overall results of adjustment achieved in Africa have so far been modest. Adjustment has not yet succeeded in raising the rate of growth enough to make major inroads in reducing poverty. Sub-Saharan Africa's economic recovery is still fragile. Currency depreciation and inflationary pressures have not yet been fully subdued in several countries because of persistence of underlying expansionary fiscal and monetary policies. Many sub-Saharan countries still rely exclusively on external grants and concessional financing to close their fiscal gaps. Per capita consumption remains stagnant, and private investment has not yet revived. Unemployment rates are still high, particularly in urban areas, and poverty is on the rise. When there is civil strife, adjustment, of course, has not worked. There is a general consensus that consistent and unfetted implementation of adjustment policies and attainment of macroeconomic stability do improve the outlook for growth in Africa. But the record of implementation is mixed and uneven. Adjustment is necessary even if it is bound to work slowly. But for it to work at all depends on the strong commitment by leaders of these countries to sustain reform policies in the face of adverse and harsh external circumstances and domestic political pressures. What is less clear, and thus invokes controversy, is the speed, timing, and sequencing of adjustment programs. As each reform has a different impact on the various segments of the population - creating winners and losers - mediating among these conflicting claims is highly political. There are no technocratic solutions or quick fixes to provide satisfactory solutions. No amount of external assistance can help in this process. Consensus-building, open communications, consultations, and debate - and reaching compromises - will bring about the durable results. But in practice, this path has proved difficult. It is equally clear that adjustment policies, even when they are put in place after reaching internal consensus, will not lift African countries out of poverty. The agenda of policy reforms should be considered as part of the broader long-term development strategy of each country. This strategy should aim not only at changes in policies, but also at improving investment in human resources and physical infrastructure, accelerating opportunities for private sector development, enhancing the quality of governance, strengthening institutional capacity, and - most importantly - maintaining national solidarity and social cohesion.Environmental Economics&Policies,Achieving Shared Growth,Economic Theory&Research,Inequality,Poverty Assessment