Littérature scientifique sur le sujet « Web service contract »
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Articles de revues sur le sujet "Web service contract"
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HOU, Ke-Jia, Xiao-Ying BAI, Hao LU, Shu-Fang LI et Li-Zhu ZHOU. « Web Service Test Data Generation Using Interface Semantic Contract ». Journal of Software 24, no 8 (16 janvier 2014) : 2020–41. http://dx.doi.org/10.3724/sp.j.1001.2013.04366.
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Monfort, Valérie, et Slimane Hammoudi. « When Parameterized Model Driven Development Supports Aspect Based SOA ». International Journal of E-Business Research 7, no 3 (juillet 2011) : 44–62. http://dx.doi.org/10.4018/jebr.2011070103.
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Service-Oriented Architectures (SOA) are widely used by companies to gain flexibility. Web services are the fitted technical solution used to support SOA by providing interoperability and loose coupling. Basic Web services are being assembled to composite Web services in order to directly support business processes. However, there is much to be done to obtain a genuine flawless Web service, and current market implementations do not provide adaptable Web service behavior depending on the service contract. This paper proposes two different approaches to increase adaptability of Web services and SOA. The first approach is based on Aspect Oriented Programming (AOP) as a new design solution for Web services. The authors have implemented an infrastructure to enrich services with aspects and to dynamically reroute messages according to changes, without redeployment. The second approach combines Model Driven Development (MDD) and Context-Awareness to promote reuse and adaptability of Web services behavior depending on the service context. Parameterized transformation techniques are proposed to bind context with business logic implemented by a service. The aim is to merge the two approaches to abstract and reduce the technical complexity of aspect based service solution.
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Mateos, Cristian, Marco Crasso, Alejandro Zunino et José Luis Ordiales Coscia. « A Stitch in Time Saves Nine : Early Improving Code-First Web Services Discoverability ». International Journal of Cooperative Information Systems 24, no 02 (juin 2015) : 1550004. http://dx.doi.org/10.1142/s0218843015500045.
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Web Services represent a number of standard technologies and methodologies that allow developers to build applications under the Service-Oriented Computing paradigm. Within these, the WSDL language is used for representing Web Service interfaces, while code-first remains the de facto standard for building such interfaces. Previous studies with contract-first Web Services have shown that avoiding a specific catalog of bad WSDL specification practices, or anti-patterns, can reward Web Service publishers as service understandability and discoverability are considerably improved. In this paper, we study a number of simple and well-known code service refactorings that early reduce anti-pattern occurrences in WSDL documents. This relationship relies upon a statistical correlation between common OO metrics taken on a service's code and the anti-pattern occurrences in the generated WSDL document. We quantify the effects of the refactorings — which directly modify OO metric values and indirectly alter anti-pattern occurrences — on service discovery. All in all, we show that by applying the studied refactorings, anti-patterns are reduced and Web Service discovery is significantly improved. For the experiments, a dataset of real-world Web Services and an academic service registry have been employed.
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TOMAZ, RICARDO FERRAZ, MEHDI BEN HMIDA et VALERIE MONFORT. « CONCRETE SOLUTIONS FOR WEB SERVICES ADAPTABILITY USING POLICIES AND ASPECTS ». International Journal of Cooperative Information Systems 15, no 03 (septembre 2006) : 415–38. http://dx.doi.org/10.1142/s0218843006001414.
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Traditional middleware is usually developed on monolithic and non-evolving entities, resulting in a lack of flexibility and interoperability. Among current architectures, Service Oriented Architectures aim to easily develop more adaptable Information Systems. Most often, Web Service is the fitted technical solution which provides the required loose coupling to achieve such architectures. However, there is still much to be done in order to obtain a genuinely flawless Web Service, and current market implementations still do not provide adaptable Web Service behavior depending on the service contract. In this paper, we present our two last years of work toward a more adaptable SOA. We proposed two approaches that consider Aspect Oriented Programming (AOP) as a new design solution for Web Services. The two approaches enable us to glue new non-functional behaviors to a Web Service without going back to modify, recompile, retest and finally redeploy it.
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HOFFNER, YIGAL, et SIMON FIELD. « TRANSFORMING AGREEMENTS INTO CONTRACTS ». International Journal of Cooperative Information Systems 14, no 02n03 (juin 2005) : 217–44. http://dx.doi.org/10.1142/s0218843005001134.
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During the life cycle of a service consumer-provider relationship, agreements are reached in a variety of areas covering technical, service, business and legal issues. Although some of these agreements may be viewed as legally binding, it is unlikely that any of them will constitute a legal contract in the full sense of the word. It is often expedient to gather these agreements and create a legal contract out of them. Automating this process of contract generation can speed up the process and reduce the cost of legal expenses. In fact, the process of automated contract generation can also be useful outside the realm of web services, when agreements are made directly among people. We propose a way of transforming such agreements into contracts in a dynamic, efficient and speedy manner, using advanced forms of matchmaking technology in a novel way. This complements the other directions in which the agreements are to be used, namely configuration, instantiation, enactment supervision and relationship termination and evaluation.
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Koll, Kristiina. « Qualification of Consumer Contracts for the Supply of Digital Services under Estonian Law ». Juridica International 30 (13 octobre 2021) : 40–48. http://dx.doi.org/10.12697/ji.2021.30.06.
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The EU Digital Content Directive provides for overarching regulation of the supply of digital content and services. In this light, the article presents analysis of how contracts for the supply of digital content or digital services can be qualified under Estonian law. More specific focus is placed on contracts for digital services such as storage in a cloud service or use of Web based software, because it is not entirely clear whether the underlying contracts should be considered some type of contract for use or, rather, some kind of contract for provision of services. The article examines the distinctive characteristics of particular types of contracts for use and for services, such as the possible object of the specific type of contract at issue and the main obligations of the parties, for purposes of determining whether they are suitable for the supply of digital content or digital services. This distinction is important for understanding of the directive’s relationship with national law and how existing rules function in conjunction with the rules of the directive. Also, it regulates only certain aspects of contract law, while the remainder of the contractual relationship is determined by national law – such as that pertaining to obligations of consumers and legal remedies available to traders. These rules may differ between contract types. The article’s analysis is based on comparison of Estonian and German law.
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Ma, Xin Qiang, Yi Huang, Dan Ning Li et You Yuan Liu. « Study on Quality of Service Based on Trusted Computing ». Applied Mechanics and Materials 556-562 (mai 2014) : 3941–44. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.3941.
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Trusted computing is a hot topic of information security technology research nowadays. It was developed based on computing and Information Systems. At the same time, business processes for e-commerce and Web service applications, suppliers and customers define a binding agreement or contract between the two parties, specifying quality of service (QoS) items such as products or services to be delivered, deadlines, quality of products, and cost of services. The management of QoS metrics directly impacts the success of organizations participating in e-commerce. In this paper, we discuss the present situation about QoS in the environment of trusted computing. It describes the factors related to each attribute, as well as possible tradeoffs and existing efforts to achieve that quality. The paper also discusses key issues in services level agreements that are used to contract the level of services quality between service providers and users.
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FARRELL, ANDREW D. H., MAREK J. SERGOT, MATHIAS SALLÉ et CLAUDIO BARTOLINI. « USING THE EVENT CALCULUS FOR TRACKING THE NORMATIVE STATE OF CONTRACTS ». International Journal of Cooperative Information Systems 14, no 02n03 (juin 2005) : 99–129. http://dx.doi.org/10.1142/s0218843005001110.
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In this work, we have been principally concerned with the representation of contracts so that their normative state may be tracked in an automated fashion over their deployment lifetime. The normative state of a contract, at a particular time, is the aggregation of instances of normative relations that hold between contract parties at that time, plus the current values of contract variables. The effects of contract events on the normative state of a contract are specified using an XML formalization of the Event Calculus, called ecXML. We use an example mail service agreement from the domain of web services to ground the discussion of our work. We give a characterization of the agreement according to the normative concepts of obligation, power and permission, and show how the ecXML representation may be used to track the state of the agreement, according to a narrative of contract events. We also give a description of a state tracking architecture, and a contract deployment tool, both of which have been implemented in the course of our work.
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Grefen, Paul, Heiko Ludwig et Samuil Angelov. « A Three-Level Framework for Process and Data Management of Complex E-Services ». International Journal of Cooperative Information Systems 12, no 04 (décembre 2003) : 487–531. http://dx.doi.org/10.1142/s0218843003000838.
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Service outsourcing is the business paradigm in which an organization has part of its business process performed by a service provider. In dynamic markets, service providers can be selected on the fly during process enactment. The cooperation between the parties is specified in a dynamically made electronic contract. This contract includes a process specification that is tailored towards service brokering and cross-organizational process enactment and, hence, has to conform to market and specification standards. Process enactment, however, relies on intra-organizational process specifications that have to comply with the infrastructure available in an organization for process and data management. In this paper, we present a three-level process and data specification framework for dynamic contract-based outsourcing of complex services. We focus on services with an externally visible control flow, as opposed to simple, black-box web services. The framework relates the two process specification levels through a third, conceptual level. This approach is inspired by the well-known ANSI-SPARC model for data management. We discuss an abstract architecture for dynamic service outsourcing based on the three-level framework. We show how the framework and architecture can be placed in the context of existing infrastructures for cross-organizational process support. As service outsourcing is used more and more for core business processes requiring reliable execution, we pay special attention to transaction management.
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Nepal, Surya, et Shiping Chen. « Dynamic Business Collaborations Through Contract Services ». International Journal of Systems and Service-Oriented Engineering 2, no 4 (octobre 2011) : 60–82. http://dx.doi.org/10.4018/ijssoe.2011100104.
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New applications have recently emerged within the domains of e-Health, e-Science, e-Research and e-Government that require the formation of dynamic collaborations between independent, autonomous business organizations for the duration of a project designed with a specific purpose. To successfully create and manage such collaborations, there is a need of a standard way to specify: (a) what resources are required, (b) who will contribute resources, (c) the type of access required to these resources, (d) agreement and obligations of the partners within the business collaboration, with the terms and conditions specified in the agreement, and (e) how to instantiate, maintain and terminate such business collaborations easily and in a well understood manner. The authors address these issues through the creation, negotiation and execution of an agreed electronic contract. First, this paper provides a framework for an electronic contract (e-Contract) by introducing a Web Service Collaborative Context Definition Language (WS-CCDL), which was developed in the context of dynamic business collaboration. Then, the authors illustrate its use with a universal (anywhere) connectivity service for a tele-Collaboration application in the context of e-Research domain. Both architectural design and implementation considerations are provided to highlight the feasibility and complicity of the technologies.
Thèses sur le sujet "Web service contract"
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Milanovic, Nikola. « Contract based web service composition ». Doctoral thesis, [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980381371.
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COMERIO, MARCO. « Web service contracts : specification, selection and composition ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2010. http://hdl.handle.net/10281/7779.
Texte intégralRésumé :
Web services promise universal interoperability and integration of
services developed by independent providers to execute business processes by discovering and composing services distributed over
the Internet. This means that a key factor to build complex and valuable processes among cooperating organizations relies on the
efficiency of discovering appropriate Web services and composing them. The increasing availability of Web services that offer
similar functionalities requires mechanisms to go beyond the pure functional discovery and composition of Web services.
A promising solution towards the automatic enactment of valuable processes consists in enhancing Web service discovery and composition with the evaluation of semantic contracts that define non-functional properties (NFPs) and applicability conditions associated with a Web service. Nevertheless, currently there is a lack of tools and algorithms that fully support this solution due to several open issues. First, existing languages do not show the expressivity necessary for Web service contract specifications. Second, there is a lack of standard languages that determines
heterogeneity in Web service contract specifications raising interoperability issues. Third, pure semantic approaches to
enhance Web service discovery allows for detailed descriptions but present performance problems due to current limitations of semantic tools when dealing with reasoning tasks. Fourth, Web service contract compatibility evaluation is not supported by existing composition tools when combining different services from different providers.
This dissertation addresses these open issues and proposes solutions in terms of models, algorithms and tools.
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Carpineti, Samuele <1978>. « Data and behavioral contracts for web services ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/368/1/CarpinetiTesi.pdf.
Texte intégralRésumé :
The recent trend in Web services is fostering a computing scenario where loosely coupled parties interact in a distributed and dynamic environment. Such interactions are sequences of xml messages and in order to assemble parties – either statically or dynamically – it is important to verify that the “contracts” of the parties are “compatible”. The Web Service Description Language (wsdl) is a standard used for describing one-way (asynchronous) and request/response (synchronous) interactions. Web Service Conversation Language extends wscl contracts by allowing the description of arbitrary, possibly cyclic sequences of exchanged messages between communicating parties. Unfortunately, neither wsdl nor wscl can effectively define a notion of compatibility, for the very simple reason that they do not provide any formal characterization of their contract languages. We define two contract languages for Web services. The first one is a data contract language and allow us to describe a Web service in terms of messages (xml documents) that can be sent or received. The second one is a behavioral contract language and allow us to give an abstract definition of the Web service conversation protocol. Both these languages are equipped with a sort of “sub-typing” relation and, therefore, they are suitable to be used for querying Web services repositories. In particular a query for a service compatible with a given contract may safely return services with “greater” contract.
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Carpineti, Samuele <1978>. « Data and behavioral contracts for web services ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/368/.
Texte intégralRésumé :
The recent trend in Web services is fostering a computing scenario where loosely coupled parties interact in a distributed and dynamic environment. Such interactions are sequences of xml messages and in order to assemble parties – either statically or dynamically – it is important to verify that the “contracts” of the parties are “compatible”. The Web Service Description Language (wsdl) is a standard used for describing one-way (asynchronous) and request/response (synchronous) interactions. Web Service Conversation Language extends wscl contracts by allowing the description of arbitrary, possibly cyclic sequences of exchanged messages between communicating parties. Unfortunately, neither wsdl nor wscl can effectively define a notion of compatibility, for the very simple reason that they do not provide any formal characterization of their contract languages. We define two contract languages for Web services. The first one is a data contract language and allow us to describe a Web service in terms of messages (xml documents) that can be sent or received. The second one is a behavioral contract language and allow us to give an abstract definition of the Web service conversation protocol. Both these languages are equipped with a sort of “sub-typing” relation and, therefore, they are suitable to be used for querying Web services repositories. In particular a query for a service compatible with a given contract may safely return services with “greater” contract.
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Caprioli, Michael J. « Contracts database part of the solution / ». [Denver, Colo.] : Regis University, 2008. http://165.236.235.140/lib/MCaprioli2008.pdf.
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LAUFER, CARLOS CESAR. « CONTRACT ORIENTED WEB SERVICES MODEL (COWS) : A SEMANTIC CONTRACT SUPPORT FOR E-BUSINESS PROCESSES ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=10017@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROO estabelecimento de um processo de negócios se faz por meio de relacionamentos entre parceiros que têm um objetivo comum. Esses relacionamentos são definidos em contratos, que podem ser explícitos ou implícitos, podem ser verbais ou escritos, e assim por diante. Quando uma pessoa busca um parceiro de negócios, ela procura um parceiro que possa completar um relacionamento definido em um contrato. Para dar suporte a esses processos na Internet (e na Web) é necessário caracterizar todos os seus aspectos, tais como: agentes, contratos, papéis, relacionamentos, interações entre os parceiros, políticas etc. Este trabalho apresenta o Contract Oriented Web Services Model (COWS) - um modelo para um ambiente apropriado para diálogos de E- Business, implementados por meio de Web Services. COWS é baseado em contratos bemdefinidos, acordados entre todas as partes envolvidas e que incorpora vários níveis de políticas. Essas políticas podem estar relacionadas a formas de pagamento, qualidade de serviço (QoS), políticas de privacidade, direitos, retorno de produtos, confiança entre parceiros, entre outros. Os contratos podem se referenciar a outros contratos e têm escopo em foros específicos, que contêm políticas globais. Um protótipo, para um ambiente Web com suporte ao COWS, foi implementado para testar os conceitos que estendem o processo de casamento de parceiros, em um processo de negócios. Todos os modelos do COWS foram especificados como ontologias, utilizando-se a linguagem Flora-2.
Business processes are established via relationships between partners with a common goal. These relationships are specified in contracts, which could be explicit or implicit, oral or written, and so on. When a person searches for a business partner, she is looking for a partner that can fulfill a relationship specified in a contract. To support such processes in the Internet (and in the Web) it is necessary to characterize all of its aspects, such as agents, contracts, roles, relationships, interactions between partners, policies, etc. This dissertation presents the Contract Oriented Web Services Model (COWS) - a model for an appropriate environment for E-Business dialogues, implemented using Web Services. COWS is based on well-defined contracts agreed upon by all concerned parties and incorporates various levels of applicable policies. These policies can be related to payment methods, quality of service (QoS), privacy policies, rights, products return, trust, etc. Contracts may refer to other contracts and are valid within forae, which have default global policies. A prototype web environment supporting COWS has been implemented to test the concepts that extend the discovery process. All COWS models have been specified as ontologies, using Flora-2.
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Wane, Gary J. « Web Services Based Agents for Supply Chain Collaborative Contract Initiation ». NSUWorks, 2003. http://nsuworks.nova.edu/gscis_etd/909.
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The goal of this research was to design a collaborative contract initiation system that protects sensitive information, and uses the ebXML service oriented architecture to provide web services, while utilizing the internal systems currently in place. The system was designed to use the Elemica trading exchange and to send CIDX Chern eStandard XML payloads across the Internet. The Elemica trading exchange was not permitted to store any sensitive data at their site, such as price, quantities or delivery dates. The contract initiation system was a combination of ebXML-based services that are executed utilizing intelligent agents. The use of software agents to implement the web services was an important component of the design. The integration with a back end ERP system at the buyer and supplier sites was specifically designed for use with SAP version 4.6. The design used the UNICEF ACT Modeling Methodology (UMM), which defines a series of steps to be followed in order to design public business processes. The public business processes were constructed to form a Business Process Specification Schema (BPSS). Once the BPSS was created the Collaboration Protocol Profiles (CPP) I Collaboration Protocol Agreements (CPA) were created. At this point the agent design took place based upon the public processes designed in the prior steps. The validation of the system relied upon: (a) The creation of test cases based on the use case scenarios; (b) syntax validation by generating XMI; (c) tracing of requirements to assure coverage; (d) a static and dynamic analysis of the model artifacts against the use cases, and (e) a walkthrough of the test cases. The development and implementation of the contract initiation system design would contribute to the elimination of the manual contract setup efforts and would significantly reduce the amount of time needed to build a trading partner relationship between a buyer and a seller. Implementation of the contract initiation process through the Elemica trading exchange can be used as a model for other trading exchanges or similar technologies.
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Almeida, Diego Benincasa Fernandes Cavalcanti de. « Characterization of changes in web services contracts based on repository mining ». Instituto Nacional de Pesquisas Espaciais (INPE), 2017. http://urlib.net/sid.inpe.br/mtc-m21b/2017/03.20.19.58.
Texte intégralRésumé :
During a software system life cycle, project modifications occur for different reasons, either for natural evolution or requirements readjustment. Regarding web services, communication contracts modifications are equally common, which induce the need for adaptation in every system node, from the service consumers to the providers. More significant those changes are, greater the efforts required for this adjustment. To help reducing the contracts changing impact over software source code, easyto-adapt systems can be designed in order to minimize the application remodeling effort. However, to make this approach possible, it is necessary to understand how those contract changes occur, analyzing the most common modification types and how often they happen. In this sense, this dissertation undertakes an evaluation of the change history of different open-source projects whose web service contracts are defined using documents in Web Service Description Language (WSDL) format. Using software repository mining with MetricMiner tool, the behavior of four modification types (addition, removal, relocation and refactoring) that occur to four XML element types (xs:element, xs:attribute, xs:complexType and xs:import) of contracts schemas was analyzed, in a universe of 139 projects whose source-codes are hosted at GitHub. As a result of this study, conclusions were that modifications of types addition and removal were more frequent than the others and take place in about 20\% of verified revisions, and that a great amount of commits the act of recording file changings to the repository and creating a new file revision are related to a small number of changings in contracts. Such results indicate that modifications tend to be spread in many revisions and that a significant amount of changes are related to inclusion or exclusion of exchanged information in contracts. Conclusions obtained serve as input to the planning of new web services and to the maintenance of existing ones, giving important knowledge about services evolution which helps reducing or even avoiding excessive adaptation effort of both clients and provides with the natural evolution of contracts.Durante o ciclo de vida de um sistema computacional, modificações no projeto ocorrem por diferentes motivos, quer sejam por necessidade de evolução ou para readequação aos requisitos. No que diz respeito a serviços web, modificações nos contratos de comunicação são igualmente comuns, o que causa a necessidade de adaptação de todos os agentes do sistema, desde os consumidores até os provedores dos serviços. Quanto mais significativas forem tais mudanças, maior será o esforço necessário para o ajuste. Para reduzir o impacto das alterações dos contratos sobre o código-fonte das aplicações, sistemas mais adaptáveis podem ser desenvolvidos de modo a minimizar o esforço de remodelagem da aplicação à nova versão do contrato. Contudo, para que tal abordagem seja possível, é necessário entender como tais mudanças em contratos ocorrem, analisando os tipos mais comuns de alterações e a frequência com que acontecem. Neste sentido, esta dissertação realiza uma avaliação do histórico de mudanças de diferentes projetos cujos contratos de serviços web são definidos por meio de documentos em formato Web Service Description Language (WSDL). Utilizando mineração de repositório com a ferramenta MetricMiner, foi analisado o comportamento de quatro tipos de modificações (adição, remoção, realocação e refatoração) que ocorrem em quatro tipos de elementos XML (xs:element, xs:attribute, xs:complexType e xs:import) dos esquemas dos contratos, num universo de 139 projetos cujos códigosfonte estão hospedados no GitHub. Como resultado deste estudo, concluiu-se que modificações dos tipos adição e remoção são bem mais frequentes que as outras e que ocorrem em cerca de 20% das revisões verificadas, além de que grande parte dos commits ato de gravar no repositório alterações em arquivos, criando novas revisões dos mesmos estão relacionados a poucas alterações dos contratos. Os resultados indicam que as modificações tendem a se espalhar por várias revisões e que parcela significante de mudanças está relacionada com inclusão ou exclusão de informações trafegadas em contratos. As conclusões obtidas servem de insumo ao planejamento de novos serviços web e de manutenção dos já existentes, fornecendo conhecimento importante sobre a evolução dos serviços que auxilia a reduzir ou mesmo evitar esforço demasiado de adaptação tanto de clientes quando de provedores quando da natural evolução dos contratos.
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Santos, Leonardo Luís dos. « Monitoramento de contratos eletrônicos baseados em características ». [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/275752.
Texte intégralRésumé :
Orientador: Maria Beatriz Felgar de ToledoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação
Made available in DSpace on 2018-08-18T09:57:32Z (GMT). No. of bitstreams: 1 Santos_LeonardoLuisdos_M.pdf: 1839851 bytes, checksum: 25ffc6acebe146f90d038cfcd48b96f4 (MD5) Previous issue date: 2011
Resumo: Muitas organizações estão atuando de forma cooperativa para atingir objetivos comuns de negócio por meio da realização de processos de negócio interorganizacionais. As empresas estão cada vez mais se concentrando nas atividades chaves de sua área de negócio e subcontratando a realização das atividades secundárias. Nesse contexto, Sistemas de Gerência de Processos de Negócio (SGPN) podem oferecer apoio automatizado à realização de processos de negócio envolvendo uma ou mais empresas. Eles são responsáveis principalmente pela definição, execução e monitoramento de processos de negócio. Os SGPNs devem oferecer a infra-estrutura tecnológica necessária para a integração dos aplicativos utilizados pelas organizações envolvidas. Organizações interessadas em parcerias de negócio na Internet precisam definir os detalhes a respeito do processo de negócio interorganizacional a ser realizado. Isso pode ser feito com o uso de contratos eletrônicos. Um contrato eletrônico é um documento eletrônico com as informações necessárias para que um processo de negócio possa ser realizado por várias organizações de forma colaborativa. No caso em que os serviços negociados são serviços Web, os contratos eletrônicos precisam conter detalhes sobre quais serviços Web podem ser invocados, como e em quais condições. Esta dissertação enfoca o monitoramento de contratos eletrônicos como um meio de verificar se as regras do contrato estão sendo seguidas. A abordagem para descrição de serviços e contratos eletrônicos usa modelos de características e conceitos de linha de produto de software. Os atributos de QoS (Quality of Service), associados aos serviços eletrônicos disponíveis, são representados por características de um modelo de características. O modelo de características elaborado serve de base para as fases de negociação, monitoramento, estabelecimento e renegociação de contrato eletrônico
Abstract: Many organizations are working cooperatively to achieve common business goals through the implementation of inter-organizational business processes. Organizations are increasingly focusing on key activities of their business area and subcontracting secondary activities. In this context Business Process Management (BPM) may provide support to the implementation of automated business processes involving one or more organizations. They are primarily responsible for defining, implementing and monitoring business processes. The BPMSs should provide the technological infrastructure necessary for the integration of applications used by the involved organizations. Organizations interested in business partnerships in the Internet need to define the details about the process of between companies business being conducted. This can be done with the use of electronic contracts. An electronic contract is an electronic document containing the information necessary for a business process can be performed by various organizations in a collaborative manner. In the case in which services are web services, electronic contracts must contain details about how Web services can be invoked, and under what conditions. This dissertation focuses on the monitoring of electronic contracts as a means to check if the rules in the contract are being obeyed. The approach for description of services, their QoS and electronic contracts uses feature modeling and concepts of software product line. The feature model for electronic contracts provides the basis for the negotiation stages, monitoring, establishment and renegotiation of the contract electronically
Mestrado
Sistemas de Informação
Mestre em Ciência da Computação
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Milanovic, Nikola [Verfasser]. « Contract based Web service composition / von Nikola Milanovic ». 2006. http://d-nb.info/980381371/34.
Texte intégralLivres sur le sujet "Web service contract"
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Thomas, Erl, dir. Web service contract design and versioning for SOA. Upper Saddle River, NJ : Prentice Hall, 2008.
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Chinhŭngwŏn, Hanʼguk Chŏngbo Sahoe, dir. Wep sŏbisŭ kyeyak, pojŭng pangan yŏnʼgu = : A research on contract and assurance method for web services. Sŏul-si : Hanʼguk Chŏngbo Sahoe Chinhŭngwŏn, 2006.
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Scruggs, Ron. Contracting for cloud services : A 6 step "How to" guide to contracting for cloud services includes a 137 element contracting checklist. Longboat Key : Government Training Inc., 2011.
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Library of Congress. Contracts & Logistics Services, dir. Physical properties of library books deacidified by Wei T'o Associates, Inc : Report to the Library of Congress Contracts & Logistics Services in response to Solicitation No. RFP90-32. Atlanta, Ga : The Institute, 1991.
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Walmsley, Priscilla, Thomas Erl, Anish Karmarkar, Hugo Haas et L. Umit Yalcinalp. Web Service Contract Design and Versioning for SOA (paperback). Pearson Higher Education & Professional Group, 2017.
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Walmsley, Priscilla, Thomas Erl, Anish Karmarkar, Hugo Haas et David Orchard. Web Service Contract Design and Versioning for SOA. Pearson Education, 2008.
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Walmsley, Priscilla, Thomas Erl, Anish Karmarkar, Hugo Haas et David Orchard. Web Service Contract Design and Versioning for SOA. Pearson Education, Limited, 2008.
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Giné, Xavier, Salma Khalid et Mansuri Ghazala. The Impact of Social Mobilization on Health Service Delivery and Health Outcomes. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198829591.003.0011.
Texte intégralRésumé :
This chapter uses a randomized community development programme in rural Pakistan to assess the impact of citizen engagement on public service delivery and maternal and child health outcomes. The programme had a strong emphasis on organizing women, who also identified health services as a development priority at baseline. At midline, we find that the mobilization effort alone had a significant impact on the performance of village-based health providers. We detect economically large improvements in pregnancy and well-baby visits by female health workers, as well as increased utilization of pre- and post-natal care by pregnant women. In contrast, the quality of supra-village health services did not improve, underscoring the importance of community enforcement and monitoring capacity for improving service delivery.
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Stapleton, Jane. Causation in the Law. Sous la direction de Helen Beebee, Christopher Hitchcock et Peter Menzies. Oxford University Press, 2010. http://dx.doi.org/10.1093/oxfordhb/9780199279739.003.0038.
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Previous accounts of ‘causation’ in the law are flawed by their failure to appreciate that causal language is used to express different information about the world. Because causal terms have been used to communicate answers to different questions, any philosophical search for a free-standing account of causation is doomed. Lawyers require precision of terminology, so they should explicitly choose just one interrogation to underlie causal usage in law. It is argued that this interrogation should be chosen to serve the wide projects of the law. In these projects the law is interested to identify when a specified factor was ‘involved’ in the existence of a particular phenomenon, where the notion of ‘involvement’ identifies a contrast between the actual world and some specified hypothetical world from which we exclude (at least) that specified factor: this contrast being that, while in the former world the phenomenon exists, in the latter it does not. (Such contrasts of necessity can be generated in three ways, all of importance to the law.)
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Drelichman, Mauricio, et Hans-Joachim Voth. Financial Folly and Spain’s Black Legend. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691151496.003.0010.
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This epilogue argues that Castile was solvent throughout Philip II's reign. A complex web of contractual obligations designed to ensure repayment governed the relationship between the king and his bankers. The same contracts allowed great flexibility for both the Crown and bankers when liquidity was tight. The risk of potential defaults was not a surprise; their likelihood was priced into the loan contracts. As a consequence, virtually every banking family turned a profit over the long term, while the king benefited from their services to run the largest empire that had yet existed. The epilogue then looks at the economic history version of Spain's Black Legend. The economic history version of the Black Legend emerged from a combination of two narratives: a rich historical tradition analyzing the decline of Spain as an economic and military power from the seventeenth century onward, combined with new institutional analysis highlighting the unconstrained power of the monarch.
Chapitres de livres sur le sujet "Web service contract"
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Díaz, Gregorio, et Luis Llana. « Contract Compliance Monitoring of Web Services ». Dans Service-Oriented and Cloud Computing, 119–33. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-40651-5_10.
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Milanovic, Nikola. « Contract-Based Web Service Composition Framework with Correctness Guarantees ». Dans Service Availability, 52–67. Berlin, Heidelberg : Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/11560333_5.
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Bíba, Jiří, Jiří Hodík, Michal Jakob et Michal Pěchouček. « Contract Observation in Web Services Environments ». Dans Service-Oriented Computing : Agents, Semantics, and Engineering, 1–11. Berlin, Heidelberg : Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-10739-9_1.
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Fantinato, Marcelo, Itana Maria de S. Gimenes et Maria Beatriz F. de Toledo. « Web Service E-Contract Establishment Using Features ». Dans Lecture Notes in Computer Science, 290–305. Berlin, Heidelberg : Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11841760_20.
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Averstegge, Michael. « Contract Based, Non-invasive, Black-Box Testing of Web Services ». Dans Service-Oriented Computing, 695–98. Berlin, Heidelberg : Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-17358-5_61.
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El Kharbili, Marwane, et Elke Pulvermueller. « Service Contract Compliance Management in Business Process Management ». Dans Emerging Web Services Technology Volume III, 105–16. Basel : Birkhäuser Basel, 2010. http://dx.doi.org/10.1007/978-3-0346-0104-7_7.
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Ling, Sea, Iman Poernomo et Heinz Schmidt. « Describing Web Service Architectures through Design-by-Contract ». Dans Computer and Information Sciences - ISCIS 2003, 1008–18. Berlin, Heidelberg : Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-540-39737-3_125.
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Zhai, Jie, Zhiqing Shao, Yi Guo et Haiteng Zhang. « Generic Contract-Regulated Web Service Composition Specification and Verification ». Dans Lecture Notes in Electrical Engineering, 137–45. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-34531-9_15.
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Comerio, Marco, Flavio De Paoli, Matteo Palmonari et Luca Panziera. « Web Service Contracts : Specification and Matchmaking ». Dans Advanced Web Services, 121–46. New York, NY : Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-7535-4_6.
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Li, Zhaoxuan, Rui Zhang et Pengchao Li. « A Secure and Efficient Smart Contract Execution Scheme ». Dans Web Services – ICWS 2020, 17–32. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-59618-7_2.
Texte intégralActes de conférences sur le sujet "Web service contract"
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Lomuscio, Alessio, Hongyang Qu et Monika Solanki. « Towards Verifying Contract Regulated Service Composition ». Dans 2008 IEEE International Conference on Web Services (ICWS). IEEE, 2008. http://dx.doi.org/10.1109/icws.2008.115.
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Wang, Chen, Shiping Chen et John Zic. « A Contract-Based Accountability Service Model ». Dans 2009 IEEE International Conference on Web Services (ICWS). IEEE, 2009. http://dx.doi.org/10.1109/icws.2009.53.
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Chen, Yonghong, Xiwei Xu et Liming Zhu. « Web Platform API Design Principles and Service Contract ». Dans 2012 19th Asia-Pacific Software Engineering Conference (APSEC). IEEE, 2012. http://dx.doi.org/10.1109/apsec.2012.24.
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Li, Junhuai, Yile Wang, Jing Zhang et Zhuobin Zhang. « A Web Service Adapter with Contract-Oriented Methodology ». Dans 2009 Eighth IEEE/ACIS International Conference on Computer and Information Science. IEEE, 2009. http://dx.doi.org/10.1109/icis.2009.42.
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Bhuiyan, J., S. Nepal et J. Zic. « Checking conformance between business processes and Web service contract in service oriented applications ». Dans Australian Software Engineering Conference (ASWEC'06). IEEE, 2006. http://dx.doi.org/10.1109/aswec.2006.20.
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Zou, Jun, Yan Wang et Mehmet A. Orgun. « A Dispute Arbitration Protocol Based on a Peer-to-Peer Service Contract Management Scheme ». Dans 2016 IEEE International Conference on Web Services (ICWS). IEEE, 2016. http://dx.doi.org/10.1109/icws.2016.15.
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Bernardo Neto, José, et Celso Hirata. « e-Business Architecture for Web Service Composition based on e-Contract Lifecycle ». Dans 17th International Conference on Enterprise Information Systems. SCITEPRESS - Science and and Technology Publications, 2015. http://dx.doi.org/10.5220/0005377902760283.
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Lau, G. K. T., D. K. W. Chiu et P. C. K. Hung. « Web-Service Based Information Integration for e-Mortgage Contract Matchmaking Decision Support : A Case Study in Hong Kong ». Dans Proceedings of the 39th Annual Hawaii International Conference on System Sciences (HICSS'06). IEEE, 2006. http://dx.doi.org/10.1109/hicss.2006.532.
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Cambronero, Emilia, Joseph C. Okika et Anders P. Ravn. « Analyzing Web Service Contracts ». Dans International Conference on Mobile Ubiquitous Computing, Systems, Services and Technologies (UBICOMM'07). IEEE, 2007. http://dx.doi.org/10.1109/ubicomm.2007.9.
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Silva, Gabriel Costa, Itana M. de Souza Gimenes, Marcelo Fantinato et Maria B. Felgar De Toledo. « Towards a Process for Negotiation of E-contracts Involving Web Services ». Dans VIII Simpósio Brasileiro de Sistemas de Informação. Sociedade Brasileira de Computação, 2012. http://dx.doi.org/10.5753/sbsi.2012.14391.
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Organizations involved in cooperative business processes have different interests and points of view. A negotiation allows them to discuss their interests and requirements in order to reach an acceptable agreement. We propose an integrated web service negotiation process that considers human interaction and the use of different protocols. It focuses on the application of feature modelling to describe the negotiated services. Our contributions include: (i) the definition of a negotiation process; (ii) the definition of a conceptual model to support the negotiation of web services; (iii) reuse of artefacts generated throughout the negotiation process; and (iv) coverage of critical elements in the negotiation of electronic contracts.
Rapports d'organisations sur le sujet "Web service contract"
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Beach, Rachel, et Vanessa van den Boogaard. Tax and Governance in the Context of Scarce Revenues : Inefficient Tax Collection and its Implications in Rural West Africa. Institute of Development Studies (IDS), février 2022. http://dx.doi.org/10.19088/ictd.2022.005.
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In recent years, domestic and international policy attention has often focused on broadening the tax base in order to include a greater share of the population in the ‘tax net’. This is based, in part, on the hope that the expansion of taxation will result in positive ‘governance dividends’ for taxpayers. However, the implications of extending the tax base in rural areas in low-income countries has been insufficiently considered. Through the case studies of Togo, Benin, and Sierra Leone, we demonstrate that extending taxation to rural areas is often highly inefficient, leading to few, if any, revenue gains when factoring in the costs of collection. Where revenues exceed the costs of collection, they often only cover local government salaries with little remaining for the provision of public goods and services. The implications of rural tax collection inefficiency are thus significant for revenue mobilisation, governance and public service delivery, accountability relationships with citizens, and taxpayer expectations of the state. Accordingly, we question the rationale for extending taxation to rural citizens in low-income countries. Instead, we argue for a reconceptualisation of the nature of the fiscal social contract, disentangling the concept of the social contract from the individual. Rather, a collective social contract places greater emphasis on the taxation of wealth and redistribution and recognises that basic rights of citizenship are not, or should not, be contingent on paying direct taxes to the government. Rather than expanding taxation, we argue for the expansion of political voice and rights to rural citizens, through a ‘services-first’ approach.
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Murguia, Juan M., Pablo Ordoñez, Leonardo Corral et Gilmar Navarrete-Chacón. Payment for Ecosystem Services in Costa Rica : Evaluation of a Country-wide Program. Inter-American Development Bank, mai 2022. http://dx.doi.org/10.18235/0004259.
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Several countries have implemented payment-for-ecosystem-services (PES) programs, buoyed by the promise of these programs as a win-win strategy that would allow both the conservation of natural resources, and the reduction of poverty for rural households and communities. Our study evaluates the effect on deforestation of Costa Rica's PES program, one of the oldest country-wide programs in the world. Costa Rica approved the 1996 Forest Law (Law No. 7575), creating a PES program that compensates landowners for forest conservation. We estimate these effects using an event study design with staggered entry into treatment. Our results show a statistically significant effect for the first year with a decrease in deforestation of 0.21 ha, but not for the following years. Given that the baseline level of deforestation in our sample is low, the magnitude of the effect is large. When compared to the pre-2016 average level of within farm deforestation, our estimated effect would imply a 100% reduction in deforestation for the first year after enrollment. Given the program pays the participants for a 5-year period, and that the effect is significant only during the first year, it may be beneficial for the program to reduce its length and implement required simplified annual contract renewals or other behavioral interventions to reduce noncompliance in subsequent years.
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Bakhtiar, M. Mehrab, Abu Sonchoy, Muhammad Meki et Simon Quinn. Virtual Migration through Online Freelancing : Evidence from Bangladesh. Digital Pathways at Oxford, août 2021. http://dx.doi.org/10.35489/bsg-dp-wp_2021/03.
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Youth unemployment is a major issue in many developing countries, particularly in locations not well connected with large urban markets. A limited number of available job opportunities in urban centres may reduce the benefit of policies that encourage rural–urban migration. In this project, we investigated the feasibility of ‘virtual migration’, by training rural youth in Bangladesh to become online freelancers, enabling them to export their labour services to a global online marketplace. We did this by setting up a ‘freelancing incubator’, which provided the necessary workspace and infrastructure – specifically, high-speed internet connectivity and computers. Close mentoring was also provided to participants to assist in navigating the competitive online marketplace. We show the exciting potential of online work for improving the incomes of poor youth in developing countries. We also highlight the constraints to this type of work: financing constraints for the high training cost, access to the necessary work infrastructure, and soft skills requirements to succeed in the market. We also shed light on some promising possibilities for innovative financial contracts and for ‘freelancing incubators’ or ‘virtual exporting companies’ to assist students in their sourcing of work and skills development.
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Kurmann, André, Étienne Lalé et Lien Ta. Measuring Small Business Dynamics and Employment with Private-Sector Real-Time Data. CIRANO, août 2022. http://dx.doi.org/10.54932/xsph3669.
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The COVID-19 pandemic has led to an explosion of research using private-sector datasets to measure business dynamics and employment in real-time. Yet questions remain about the representativeness of these datasets and how to distinguish business openings and closings from sample churn – i.e., sample entry of already operating businesses and sample exits of businesses that continue operating. This paper proposes new methods to address these issues and applies them to the case of Homebase, a real-time dataset of mostly small service-sector sector businesses that has been used extensively in the literature to study the effects of the pandemic. We match the Homebase establishment records with information on business activity from Safegraph, Google, and Facebook to assess the representativeness of the data and to estimate the probability of business closings and openings among sample exits and entries. We then exploit the high frequency / geographic detail of the data to study whether small service-sector businesses have been hit harder by the pandemic than larger firms, and the extent to which the Paycheck Protection Program (PPP) helped small businesses keep their workforce employed. We find that our real-time estimates of small business dynamics and employment during the pandemic are remarkably representative and closely fit population counterparts from administrative data that have recently become available. Distinguishing business closings and openings from sample churn is critical for these results. We also find that while employment by small businesses contracted more severely in the beginning of the pandemic than employment of larger businesses, it also recovered more strongly thereafter. In turn, our estimates suggests that the rapid rollout of PPP loans significantly mitigated the negative employment effects of the pandemic. Business closings and openings are a key driver for both results, thus underlining the importance of properly correcting for sample churn.
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Rine, Kristin, Roger Christopherson et Jason Ransom. Harlequin duck (Histrionicus histrionicus) occurrence and habitat selection in North Cascades National Park Service Complex, Washington. National Park Service, avril 2022. http://dx.doi.org/10.36967/nrr-2293127.
Texte intégralRésumé :
Harlequin ducks (Histrionicus histrionicus) are sea ducks that migrate inland each spring to nest along fast-flowing mountain streams. They are considered one of the most imperiled duck species in North America and occur in two distinct populations on the Atlantic and Pacific coasts. The Pacific coast population includes Washington State, where harlequin ducks breed in the Olympic, Cascade, and Selkirk Mountains. This species is designated as a Management Priority Species by the National Park Service within North Cascades National Park Service Complex (NOCA). This report summarizes harlequin duck surveys conducted during 15 years across a 27-year period (1990 and 2017) on major streams within NOCA, and incidental observations collected from 1968–2021. The primary objectives of these surveys were to 1) document the distribution and abundance of harlequin duck observations within NOCA boundaries, 2) describe productivity (number of broods and brood size), 3) describe breeding chronology of harlequin ducks, and 4) describe habitat characteristics of breeding streams. Sixty-eight stream surveys over 15 years resulted in observations of 623 individual harlequin ducks comprising various demographics, including single adults, pairs, and broods. In addition, we collected 184 incidental observations of harlequin ducks from visitors and staff between 1968–2021. Harlequin ducks were observed on 22 separate second- to sixth-order streams throughout NOCA across the entire 53-year span of data, both incidentally and during harlequin duck surveys by Park staff. Harlequin ducks were detected on 8 of the 13 streams that were actively surveyed. Excluding recounts, 88.7% (n = 330) of individual harlequin duck observations during surveys occurred in the Stehekin River drainage. Between all surveys and incidental observations, 135 unpaired females without broods were sighted across all NOCA waterways. Thirty-nine broods were recorded between NOCA surveys and incidental observations, with a mean brood size of 3.61 (± 1.44 SD; range = 2–10). Breeding pairs were recorded as early as April 5 and were seen on streams until June 15, a period of less than seven weeks (median: May 2), but most pairs were observed within a 3-week span, between April 26 and May 17. Single females (unpaired with a male, with (an)other female(s), or with a brood) were observed on streams between April 26 and August 25 (median: July 3), though most observations were made within a 5-week period between June 12 and July 19. Habitat data collected at adult harlequin duck observation sites indicate that the birds often used stream reaches with features that are characteristic of high-energy running water. While adults occupied all instream habitat types identified, non-braided rapids and riffles were used most frequently, followed by pools and backwaters. Larger instream substrate sizes (cobbles and boulders) were present at most observation sites. Adult harlequin ducks were more often found at locations that lacked visible drifting or lodged woody debris, but drift debris was a slightly more abundant debris type. The presence of gravel bars and at least one loafing site was common. Adult harlequin ducks were more often observed in association with vegetation that offered some cover over the channel, but not where banks were undercut. The average channel width at adult observation sites was 34.0 m (range: 6-80 m; n = 114) and 27.6 m (± 15.7 m; range: 10-60 m; n = 12) at brood observation sites. Compared to adult harlequin duck sites, broods were observed more frequently in low velocity habitat (pools, backwaters), but rarely in rapids. Cobble and boulder substrates were still the most dominant substrate type. Contrary to adult ducks, broods were observed most often observed in meandering stream channels, a morphology indicative of low gradient, low velocity stream reaches. Most broods were observed in stream reaches with gravel bars, loafing sites, and...
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Splitter, Gary, Zeev Trainin et Yacov Brenner. Lymphocyte Response to Genetically Engineered Bovine Leukemia Virus Proteins in Persistently Lymphocytic Cattle from Israel and the U.S. United States Department of Agriculture, juillet 1995. http://dx.doi.org/10.32747/1995.7570556.bard.
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The goal of this proposal was to identify proteins of BLV recognized by lymphocyte subpopulations and determine the contribution of these proteins to viral pathogenesis. Our hypothesis was that BLV pathogenesis is governed by the T-cell response and that the immune system likely plays an important role in controlling the utcome of infection. Our studies presented in ths final report demonstrate that T cell competency declines with advancing stages of infection. Dramatic differences were observed in lymphocyte proliferation to recombinant proteins encoded by BLV gag (p12, p15, and p24) and env (gp30 and gp15) genes in different disease stages. Because retroviruses are known to mutate frequently, examinatin of infected cattle from both Israel and the United States will likely detect variability in the immune response. This combined research approach provides the first opportunity to selectively address the importance of T-cell proliferation to BLV proteins and cytokines produced during different stages of BLV infection. Lack of this information regarding BLV infection has hindered understanding lympocyte regulation of BLV pathogenesis. We have developed the essential reagents necessary to determine the prominence of different lymphocyte subpopulations and cytokines produced during the different disease stages within the natural host. We found that type 1 cytokines (IL-2 and IFN-g) increased in PBMCs from animals in early disease, and decreasd in PBMCs from animals in late disease stages of BLV infection, while IL-10, increased with disease progression. Recently, a dichotomy between IL-12 and IL-10 has emerged in regards to progression of a variety of diseases. IL-12 activates type 1 cytokine production and has an antagonistic effect on type 2 cytokines. Here, using quantitative competitive PCR, we show that peripheral blood mononuclear cells from bovine leukemia virus infected animals in the alymphocytotic disease stage express increased amount of IL-12 p40 mRNA. In contrast, IL-12 p40 mRNA expression by PL animals was significantly decreased compared to normal and alymphocytotic animals. To examine the functions of these cytokines on BLV expression, BLV tax and pol mRNA expression and p24 protein production were quantified by competitive PCR, and by immunoblotting, respectively. IL-10 inhibited BLV tax and pol mRNA expression by BLV-infected PBMCs. In addition, we determined that macrophages secret soluble factor(s) that activate BLV expression, and that secretion of the soluble factor(s) could be inhibited by IL-10. In contrast, IL-2 increased BLV tax and pol mRNA, and p24 protein production. These findings suggest that macrophages have a key role in regulating BLV expression, and IL-10 produced by BLV-infected animals in late disease stages may serve to control BLV expression, while IL-2 in the early stage of disease may activate BLV expression. PGE2 is an important immune regulator produced only by macrophages, and is known to facilitate HIV replication. We hypothesized that PGE2 may regulate BLV expression. Here, we show that cyclooxygenase-2 (COX-2) mRNA expression was decreased in PBMCs treated with IL-10, while IL-2 enhanced COX-2 mRNA expression. In contrast, addition of PGE2 stimulated BLV tax and pol mRNA expression. In addition, the specific COX-2 inhibitor, NS-398, inhibited BLV expression, while addition of PGE2 increased BLV tax expression regardless of NS-398. These findings suggest that macrophage derived cyclooxygenase -2 products, such as PGE2, may regulate virus expression and disease rogression in BLV infection, and that cytokines (IL-2 and IL-10) may regulate BLV expression through PGE2 production.
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Agusti Strid, Alma, et James Ronicle. Social Impact Bonds in Latin America : IDB Lab's Pioneering Work in the Region : Lessons Learnt. Sous la direction de Christine Ternent. Inter-American Development Bank, janvier 2021. http://dx.doi.org/10.18235/0003004.
Texte intégralRésumé :
In recent years, Latin America has seen the introduction of innovative pay-for-success mechanisms to fund social programs, including Social Impact Bonds (SIBs) and Development Impact Bonds (DIBs), outcome-based contracts that incorporate the use of private financing from investors to cover the upfront capital required for a provider to set up and deliver a social service. In this context, IDB Lab established a SIB Facility in 2014 to promote the focus on outcomes in social programs and increase outcomes-based commissioning. The SIB Facility has resulted in IDB Lab providing support to developing SIBs in Colombia (first SIB launched in a middle-income country), Argentina, Chile, Mexico and Brazil. Since then, several employment SIBs have launched in Colombia and Argentina and prefeasibility studies for SIBs on other topics are currently underway in Chile. This Technical Note aims to capture the lessons learnt from developing SIBs in Latin America, focusing on the five countries where the SIB Facility played a pioneering role. The study takes a retrospective view in examining what has been done and a prospective view in considering how challenges can be overcome and how lessons learnt might be considered within the IDB Lab, both at SIB level and at ecosystem level looking at the SIB ecosystems that have started to emerge. In the study, we find that the SIBs that have launched in the study countries were well designed and that there had also been thorough consideration of the advantages and disadvantages of the model.
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van den Boogaard, Vanessa, et Fabrizio Santoro. Explaining Informal Taxation and Revenue Generation : Evidence from south-central Somalia. Institute of Development Studies, mars 2021. http://dx.doi.org/10.19088/ictd.2021.003.
Texte intégralRésumé :
Most people in low-income countries contribute substantially to the financing of local public goods through informal revenue generation (IRG). However, very little is known about how IRG works in practice. We produce novel evidence on the magnitude and regressivity of IRG and its relationship with the state in a fragile context, Somalia. We rely on original data from surveys with over 2,300 households and 117 community leaders in Gedo region, as well as on extensive qualitative research. We first show that IRG is prevalent. Over 70 per cent of households report paying at least one informal tax or fee in the previous year, representing on average 9.5 per cent of annual income. We also find that, among households that contribute, poorer ones contribute larger amounts than richer ones, with higher incidence in relation to their income. Further, in line with theory and expectations, informal payments have inequitable community-level effects, with individuals in wealthier communities making more informal payments than in poorer ones and, correspondingly, having access to a greater number of public goods. We then consider four explanations for the prevalence of IRG. First, IRG clearly fills gaps left by weak state capacity. Relatedly, we show that IRG can bolster perceptions and legitimacy of the state, indicating that sub-national governments may actually benefit from informal taxation. Second, informal taxing authorities are more effective tax collectors than the state, with informal taxing authorities having greater legitimacy and taxpayers perceiving informal payments to be fairer than those levied by the state. Third, dispelling the possibility that informal payments should be classified as user fees, taxpayers overwhelmingly expect nothing in return for their contributions. Fourth, in contrast to hypotheses that informal payments may be voluntary, taxpayers associate informal payments with punishment and informal institutions of enforcement. Our research reinforces the importance of IRG to public goods provision in weak formal institutional contexts, to everyday citizens, and to policymakers attempting to extend the influence of the federal state in south-central Somalia. Foremost, informal tax institutions need to be incorporated within analyses of taxation, service delivery, social protection, and equity. At the same time, our findings of the complementary nature of IRG and district-level governance and of the relative efficiency of revenue generation by local leaders have important implications for understanding statebuilding processes from below. Indeed, our findings suggest that governments may have little incentive to extend their taxing authority in some fragile contexts.
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Hochman, Ayala, Thomas Nash III et Pamela Padgett. Physiological and Biochemical Characterization of the Effects of Oxidant Air Pollutants, Ozone and Gas-phase Nitric Acid, on Plants and Lichens for their Use as Early Warning Biomonitors of these Air Pollutants. United States Department of Agriculture, janvier 2011. http://dx.doi.org/10.32747/2011.7697115.bard.
Texte intégralRésumé :
Introduction. Ozone and related oxidants are regarded as the most important phytotoxic air pollutant in many parts of the western world. A previously unrecognized component of smog, nitric acid, may have even greater deleterious effects on plants either by itself or by augmenting ozone injury. The effects of ozone on plants are well characterized with respect to structural and physiological changes, but very little is known about the biochemical changes in plants and lichens exposed to ozone and/or HNO3. Objectives.To compare and contrast the responses of crop plants and lichens to dry deposition of HNO3 and O3., separately, and combined in order to assess our working hypothesis that lichens respond to air pollution faster than plants. Lichens are most suitable for use as biomonitors because they offer a live-organism-based system that does not require maintenance and can be attached to any site, without the need for man-made technical support systems. Original Immediate aims To expose the tobacco (Nicotiana tabacum L.) cultivar Bel-W3 that is ozone supersensitive and the ozone sensitive red kidney bean (Phaseolusvulgaris) and the lichen Ramalinamenziesii to controlled HNO3 and O3 fumigations and combined and to follow the resulting structural, physiological and biochemical changes, with special reference to reactive oxygen species related parameters. Revised. Due to technical problems and time limitations we studied the lichen Ramalinamenziesii and two cultivar of tobacco: Bel-W3 that is ozone supersensitive and a resistant cultivar, which were exposed to HNO3 and O3 alone (not combined). Methodology. Plants and lichens were exposed in fumigation experiments to HNO3 and O3, in constantly stirred tank reactors and the resulting structural, physiological and biochemical changes were analyzed. Results. Lichens. Exposure of Ramalinamenziesiito HNO3 resulted in cell membrane damage that was evident by 14 days and continues to worsen by 28 days. Chlorophyll, photosynthesis and respiration all declined significantly in HNO3 treatments, with the toxic effects increasing with dosage. In contrast, O3 fumigations of R. menziesii showed no significant negative effects with no differences in the above response variables between high, moderate and low levels of fumigations. There was a gradual decrease in catalase activity with increased levels of HNO3. The activity of glutathione reductase dropped to 20% in thalli exposed to low HNO3 but increased with its increase. Glucose 6-phosphate dehydrogenase activity increase by 20% with low levels of the pollutants but decreased with its increase. Tobacco. After 3 weeks of exposure of the sensitive tobacco cultivar to ozone there were visible symptoms of toxicity, but no danmage was evident in the tolerant cultivar. Neither cultivar showed any visible symptoms after exposure to HNO3.In tobacco fumigated with O3, there was a significant decrease in maximum photosynthetic CO2 assimilation and stomatal conductance at high levels of the pollutant, while changes in mesophyll conductance were not significant. However, under HNO3 fumigation there was a significant increase in mesophyll conductance at low and high HNO3 levels while changes in maximum photosynthetic CO2 assimilation and stomatal conductance were not significant. We could not detect any activity of the antioxidant enzymes in the fumigated tobacco leaves. This is in spite of the fact that we were able to assay the enzymes in tobacco leaves grown in Israel. Conclusions. This project generated novel data, and potentially applicable to agriculture, on the differential response of lichens and tobacco to HNO3 and O3 pollutants. However, due to experimental problems and time limitation discussed in the body of the report, our data do not justify yet application for a full, 4-year grant. We hope that in the future we shall conduct more experiments related to our objectives, which will serve as a basis for a larger scale project to explore the possibility of using lichens and/or plants for biomonitoring of ozone and nitric acid air pollution.
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Sharon, Amir, et Maor Bar-Peled. Identification of new glycan metabolic pathways in the fungal pathogen Botrytis cinerea and their role in fungus-plant interactions. United States Department of Agriculture, 2012. http://dx.doi.org/10.32747/2012.7597916.bard.
Texte intégralRésumé :
The involvement of glycans in microbial adherence, recognition and signaling is often a critical determinant of pathogenesis. Although the major glycan components of fungal cell walls have been identified there is limited information available on its ‘minor sugar components’ and how these change during different stages of fungal development. Our aim was to define the role of Rhacontaining-glycans in the gray mold disease caused by the necrotrophic fungus B. cinerea. The research was built on the discovery of two genes, Bcdhand bcer, that are involved in formation of UDP-KDG and UDP-Rha, two UDP- sugars that may serve as donors for the synthesis of cell surface glycans. Objectives of the proposed research included: 1) To determine the function of B. cinereaBcDh and BcEr in glycan biosynthesis and in pathogenesis, 2) To determine the expression pattern of BcDH and BcERand cellular localization of their encoded proteins, 3) Characterize the structure and distribution of Rha- containing glycans, 4) Characterization of the UDP-sugar enzymes and potential of GTs involved in glycanrhamnosylation. To address these objectives we generated a series of B. cinereamutants with modifications in the bchdhand bcergenes and the phenotype and sugar metabolism in the resulting strains were characterized. Analysis of sugar metabolites showed that changes in the genes caused changes in primary and secondary sugars, including abolishment of rhamnose, however abolishment of rhamnose synthesis did not cause changes in the fungal phenotype. In contrast, we found that deletion of the second gene, bcer, leads to accumulation of the intermediate sugar – UDP- KDG, and that such mutants suffer from a range of defects including reduced virulence. Further analyses confirmed that UDP-KDG is toxic to the fungus. Studies on mode of action suggested that UDP-KDG might affect integrity of the fungal cell wall, possibly by inhibiting UDP-sugars metabolic enzymes. Our results confirm that bcdhand bcerrepresent a single pathway of rhamnose synthesis in B. cinerea, that rhamnose does not affect in vitro development or virulence of the fungus. We also concluded that UDP-KDG is toxic to B. cinereaand hence UDP-KDG or compounds that inhibit Er enzymes and lead to accumulation of UDP-KDG might have antifungal activity. This toxicity is likely the case with other fungi, this became apparent in a collaborative work with Prof. Bart Thomma of Wageningen University, NETHERLANDS . We have shown the deletion of ER mutant in Verticillium dahlia gave plants resistance to the fungal infection.