Springer Professional. Back to the search result list. This situation particularly occurs for transactional services. However, the absence of a rigorous definition of these BPEL constructors makes it difficult to correctly define the transactional behaviour of a BPEL process. The definitions of such constructs are usually given by their informal descriptions available in the standards.
Our contribution proposes an approach to formally define the semantics of these operators. Thus, this paper presents a new Event-B semantics for formal modelling of Web service compositions that covers the scope, the fault and the compensation handlers introduced by the BPEL language specification. The proposed approach is illustrated by a case study. The term service is today defined and used in a multitude of ways, which are often ambiguous and contradictory. The absence of a commonly agreed-upon definition of the term makes it difficult to distinguish, describe and classify services.
In order to address these issues, this chapter proposes a model of services that helps in analysing the concept. The model encompasses three perspectives: service as a means for cocreation of value, service as a means for abstraction and service as a means for distributing rights. The model does not suggest a definition of the term service but shows how the service concept can be analysed using a number of related concepts, like service resource, service process and service offering.
We present SecureMDD, a development method for secure service applications that integrates a model-driven approach with formal specification techniques using abstract state machines ASMs , refinement to code and verification with the interactive theorem prover KIV.
Web-based vs. Desktop Software: Which Is Better?
A larger case study is used to highlight various aspects of the method with a focus on services and their formal verification. In our former work, we have showed that cloud computing still requires lots of fundamental research. Among many other existing problems in cloud computing, we identified the lack of client orientation and lack of formal foundations as serious deficiencies.
In this chapter, we give a summary on our research and discuss the architectures as well as the formal models of some software solutions with which we are going to address a part of these two problems in cloud computing. The solution we propose is a novel and uniform client-cloud interaction approach by which cloud service owners, who may be different from the cloud providers, are able to fully control the usage of their services in the case of each user subscription.
In this context, any cloud service can be invoked by distinct devices; therefore, the content must be adapted to various channels and end devices, in particular with respect to needs arising from mobile clients. An extension of the client-cloud interaction model enables client-to-client interaction CTCI in an almost direct way, so that the involvement of cloud services is transparent to the users.
In this chapter, we propose a formalization of this solution that incorporates the major advantages of abstract state machines ASMs and ambient calculus by specifying the algorithms of executable components agents in terms of ASMs and by describing their communication topology, locality, and mobility in the terms of ambient calculus.
Services as an emerging paradigm in modern information technology IT infrastructures underwent the first hype for service-oriented computing caused by Web services and the second hype by IT market pressures on large corporations e. SAP , leading to standardisations incorporating logical-level specifications leaving much of the low-level details unaccounted for.
The conception of a service needs a conceptual reflection. However, the service notation lacks a conceptual model.
This gap is caused by the variety of aspects that must be reflected, such as the handling of the services as a collection of offerings, a proper annotation facility beyond ontologies, a tool to describe the service concept and the specification of the added value of a business user. Those requirements must be handled at the same time. This has been considered as an excellent tool for connecting different environments and also establishing connections between wide varieties of computers.
Q 8 Enlist few advantages of web services? Ans: We have already discussed web services, its architecture, components. Now, let us see some its advantages. It is used for publishing and finding web services over the web as it acts like a directory. Some of the features of UDDI are explained below.
BEEP is determined as building new protocols for the variety of applications such as instant messaging, network management, file transfer etc. It has some built-in features like. Q 12 Enlist few tools used to test web services? Q 13 Do we require any special application to access web service?
The top 5 software architecture patterns: How to make the right choice
Ans: The only requirement for accessing web services from any application is that it must support XML-based request and response. There is no need or say the requirement of installing any application for accessing web services. REST is defined as the stateless client-server architectural style for developing application accessed over the web.
In this architectural style, data and functionality are served as resources and is accessed by URI Uniform Resource Identifiers. Ans: Resource is said to be a fundamental concept having a type and relationship with other resources. Ans: Purpose of URI is to locate resources on the server that are hosting web services. Q 22 Enlist advantages and disadvantages of statelessness?
- How to choose the right software architecture: The top 5 patterns!
- A Look at School Crime Safety (Safety and Risk in Society).
- Web Services.
Some of the best practices include the following. Ans: Simple Object Access Protocol SOAP is defined as the XML based protocol which is known for designing and developing web services as well as enabling communication between applications developed on different platforms with different programming languages over the internet. It is both platform and language independent. These are explained as follows.
In this case, all the HTTP ports except those which bypass firewall are locked. In some cases, a technical issue of mixing specification of message transport with message structure is also observed. Ans: We have seen the basic work of a SOAP envelope element in the previous answer, now let us see some of its characteristics. Here application components provide services to the other components using communication protocol over the network.
This communication involves data exchanging or some coordination activity between services. Q 33 What are the primary security issues of web service? Ans: To ensure reliable transactions and secure confidential information, web services requires very high level of security which can be only achieved through Entrust Secure Transaction Platform. Security issues for web services are broadly divided into three sections as described below.
Weitere vorgeschlagene Titel
Whenever messages or say XML requests are sent by the client along with the service path to the server, they must be encrypted. Thus, maintaining the confidentiality of the communication is a must. There are several options that can be considered for this purpose.
Q 34 What do you know about foundation security services? Q 35 What is Entrust Identification Service? Ans: Entrust Identification Service is categorized under Entrust Secure Transaction Platform which provides essential security capabilities to ensure secure transactions. This usually allows companies to fully control the identities that are trusted to perform web service transactions.
Q 36 What is Entrust Entitlements Service? Ans: Entrust Entitlement service is those whose task is to verify the services that are attempting to access the web services. It basically ensures security in business operations as well as some authentication services. Ans: As the name suggests, Entrust Privacy Service perform encryption of the data so that only concerned parties are able to access the data. It basically deals with two factors. It is a simple XML document which comes under the Service Description layer of Web Service Protocol Stock and describes the technical details or locates the user interface to web service.