908 resultados para Semantic Web Services


Relevância:

80.00% 80.00%

Publicador:

Resumo:

The introduction of Web services into grids helped to address their two main obstacles to be embraced by business and industry, heterogeneity and useability. However, many problems are still open, e.g., grid reconfiguration, reliability and computing optimization. We argue here that a mechanism that could help solving these problems is Web Service migration, a part of automatic and transparent brokerage. Web service migration presents a number of new requirements not addressed in traditional process migration, being the outcome of Web services specific configuration of hosts and application servers, and availability of Web services / resources state. In this paper we report on our study into the development of a Web service migration facility focused on providing migration of services in a Service Oriented Grid environment. We present a novel approach to Web service migration, embodied in a System Management Broker, which is transparent, interoperable and flexible. We take the requirements of Web services into consideration when discovering suitable destination hosts and match services to suitable grid resources which are able to fulfil the needs of the service. We discuss a number of experiments conducted with different types of grid and Web service applications to highlight the feasibility and effectiveness of our migration facility and demonstrate how our facility significantly improves Service Oriented Grids.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

One of the characteristics of the current Web services is that many clients request the same or similar service from a group of replicated servers, e.g. music or movie downloading in peer-to-peer networks. Most of the time, servers are heterogeneous ones in terms of service rate. Much of research has been done in the homogeneous environment. However, there is has been little done on the heterogeneous scenario. It is important and urgent that we have models for heterogeneous server groups for the current Internet applications design and analysis. In this paper, we deploy an approximation method to transform heterogeneous systems into a group of homogeneous system. As a result, the previous results of homogeneous studies can be applied in heterogeneous cases. In order to test the approximation ratio of the proposed model to real applications, we conducted simulations to obtain the degree of similarity. We use two common strategies: random selection algorithm and Firs-Come-First-Serve (FCFS) algorithm to test the approximation ratio of the proposed model. The simulations indicate that the approximation model works well.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Over the last couple of months a large number of distributed denial of service (DDoS) attacks have occurred across the world, especially targeting those who provide Web services. IP traceback, a counter measure against DDoS, is the ability to trace IP packets back to the true source/s of the attack. In this paper, an IP traceback scheme using a machine learning technique called intelligent decision prototype (IDP), is proposed. IDP can be used on both probabilistic packet marking (PPM) and deterministic packet marking (DPM) traceback schemes to identify DDoS attacks. This will greatly reduce the packets that are marked and in effect make the system more efficient and effective at tracing the source of an attack compared with other methods. IDP can be applied to many security systems such as data mining, forensic analysis, intrusion detection systems (IDS) and DDoS defense systems.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

A common architecture in today's development of distributed systems is the service-oriented architecture (SOA) implemented using Web services. Until recently, it was difficult to build a SOA based grid/distributed system using Web services due to the inability to learn the state of services. The state of a Web service could only be accessed through specialized clients and/or services. Should the specialized client or service fail, the state can't be accessed. This paper shows the innovative resources via Web instances (RVWI) framework. RVWI grants to web services the ability to show the state of dynamic resources in their WSDL. This was achieved via software components called connectors which watch for any changes in a resource and updates the web service. The significance of this report is the support for resources which can change state between requests and the innovation is the improvement of state updates between the service and discovery services.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Devices, standards and software develop rapidly, but still often independently of each other. This creates problems in terms of content suitability on various devices. Also, in mobile environment, user and system-level applications must execute subject to a variety of resource constraints. In order to deal with these constraints, content adaptation is required. In this chapter, we justify the need of distributed cross media content adaptation and the potential of utilizing Web Services as the adaptation providers. We introduce request-driven context to complement constraint-driven and utility-driven approaches. We describe the request context mapping and propose a novel path’s determination scheme for determining the optimal service proxies to facilitate the adaptation tasks. To better illustrate the disjoint portions in content passing between service proxies, two communication models were associated. Then, within Web Services, we explain the related protocols and socket connection between adaptation’s services. We conclude with discussion regarding the strengths of the proposed architecture.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Distributed denial of service (DDoS) attack is a continuous critical threat to the Internet. Derived from the low layers, new application-layer-based DDoS attacks utilizing legitimate HTTP requests to overwhelm victim resources are more undetectable. The case may be more serious when suchattacks mimic or occur during the flash crowd event of a popular Website. In this paper, we present the design and implementation of CALD, an architectural extension to protect Web servers against various DDoS attacks that masquerade as flash crowds. CALD provides real-time detection using mess tests but is different from other systems that use resembling methods. First, CALD uses a front-end sensor to monitor thetraffic that may contain various DDoS attacks or flash crowds. Intense pulse in the traffic means possible existence of anomalies because this is the basic property of DDoS attacks and flash crowds. Once abnormal traffic is identified, the sensor sends ATTENTION signal to activate the attack detection module. Second, CALD dynamically records the average frequency of each source IP and check the total mess extent. Theoretically, the mess extent of DDoS attacks is larger than the one of flash crowds. Thus, with some parameters from the attack detection module, the filter is capable of letting the legitimate requests through but the attack traffic stopped. Third, CALD may divide the security modules away from the Web servers. As a result, it keeps maximum performance on the kernel web services, regardless of the harassment from DDoS. In the experiments, the records from www.sina.com and www.taobao.com have proved the value of CALD.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Clouds refer to computational resources (in particular, clusters) that are accessible as scalable, on demand, pay-as- you-go services provided in the Internet. However, clouds are in their infancy and lack a high level abstraction. Specifically, there is no effective discovery and selection service for clusters and offer little to no ease of use for clients. Here we show a technology that exposes clusters as Web services in the form of a Cluster as a Service for publishing via WSDL, discovering, selecting and using clusters.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The general idea of cloud computing is offering computational resources as scalable, on demand services accessible over the internet. However, this new realisation of on demand computing is hindered by the amount of user involvement. Currently, high level abstractions in cloud computing only exist in the form of services. In particular, there is no effective means to publish, discover and finally use required services in clouds. In response, we propose a user level abstraction on top of already available cloud abstraction layers, present its concept using the resources via web services (RVWS) framework and demonstrate its feasibility by simplifying the exposure and use of clusters, a commonly used resource in cloud computing.

Relevância:

80.00% 80.00%

Publicador:

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The emergence of cloud computing has caused a significant change in how IT infrastructures are provided to research and business organizations. Instead of paying for expensive hardware and incur excessive maintenance costs, it is now possible to rent the IT infrastructure of other organizations for a minimal fee. While the existence of cloud computing is new. The elements used to create clouds have been around for some time. Cloud computing systems have been made possible through the use of large-scale clusters, service-oriented architecture (SOA), Web services, and virtualization. While the idea of offering resources via Web services is commonplace in cloud computing, little attention has been paid to the clients themselves specifically, human operators. Despite that clouds host a variety of resources which in turn are accessible to a variety of clients, support for human users is minimal.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

This special issue mainly focuses on the timely topic of “Data and Security in Web Service”. More specially, from the perspective of service construction, the future Web service should address issues such as how to construct an intelligent service which can effectively perceive the individual behavior, identify and satisfy individual requirements. On the other hand, from the perspective of service utilization, in the dynamic environment, Web services should address issues such as how to utilizing security-related techniques. In this JNW special issue, we select and edit 6 most relevant papers with higher reviewer scores from 16 submissions, which give effective discussion about Web service management methodologies from different perspective.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Integrating online social networks (OSN) with e-commerce is a part of Enterprise 2.0 and social media and is of significance for development of e-commerce and online social networking services. However, how to integrate online social networks including Facebook with e-commerce is still a big issue for companies. Case based reasoning (CBR) has a number of successful applications in e-commerce and web services. This article examines how to integrate OSN with e-commerce, how to integrate CBR with e-commerce and how to integrate CBR with OSN. This article also proposes a CBR architecture for integrating online social networks with e-commerce using CBR as an intelligent intermediary. One of the research findings indicates that the principle of CBR is a useful marketing strategy for integrating e-commerce and OSN. The approach proposed in this research will facilitate the development of e-commerce, Enterprise 3.0 and online social networking services.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Research has shown that data security has always been an important aspect of quality of service for data service providers; but cloud computing poses new and challenging security threats. The most common security concerns for users of cloud storage are data confidentiality, integrity and availability. Microsoft has considered these concerns and responded with the Azure virtual private storage based on Searchable Encryption. Amazon has also responded to these security issues with its Amazon Web Services. In this paper, we investigate and compare in depth the features of Microsoft Azure and Amazon Web Services deemed to provide security with a particular focus on confidentiality, integrity and availability of data.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Stroke is a common neurological condition which is becoming increasingly common as the population ages. This entails healthcare monitoring systems suitable for home use, with remote access for medical professionals and emergency responders. The mobile phone is becoming the easy access tool for self-evaluation of health, but it is hindered by inherent problems including computational power and storage capacity. This research proposes a novel cloud based architecture of a biomedical system for a wearable motion kinematic analysis system which mitigates the above mentioned deficiencies of mobile devices. The system contains three subsystems: 1. Bio Kin WMS for measuring the acceleration and rotation of movement 2. Bio Kin Mobi for Mobile phone based data gathering and visualization 3. Bio Kin Cloud for data intensive computations and storage. The system is implemented as a web system and an android based mobile application. The web system communicates with the mobile application using an encrypted data structure containing sensor data and identifiable headings. The raw data, according to identifiable headings, is stored in the Amazon Relational Database Service which is automatically backed up daily. The system was deployed and tested in Amazon Web Services.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

In 2007, I asked for a show of hands of people who ‘might consider online dating as a way of finding a partner’. Not a single hand went up and the lecture theatre was stony silent. The same question, some five years later resulted in a significant show of hands and a buzz of chatter. Something had changed and perceptions around online dating had shifted. Nielsen Research last year found most Australians (51 per cent) had either tried online dating or would consider doing so. RSVP and eHarmony claim to have 2 million members and more than 4 million people have apparently joined RSVP since it was launched 17 years ago. Online dating is experiencing significant growth in Asia as well, with the number of new web services (some, like ‘Muslima’, are tightly focused) growing exponentially. Online dating is a global phenomenon. This paper will use current media studies research literature and data from conversations with university students in Australia and Indonesia to explore how the changing world of online dating is helping/hindering young people as they shape and develop identity, represent themselves in the virtual world and ultimately, how they find love on line.