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Abhishek Srivastava

Publications and source records attributed to Abhishek Srivastava.

41 records · Page 3Linked to original sources

A Dynamic Web Service Registry Framework for Mobile Environments

Advancements in technology have transformed mobile devices from being mere communication widgets to versatile computing devices. Proliferation of these hand held devices has made them a common means to access and process digital information. Most web based applications are today available in a form that can conveniently be accessed over mobile devices. However, webservices (applications meant for consumption by other applications rather than humans) are not as commonly provided and consumed over mobile devices. Facilitating this and in effect realizing a service-oriented system over mobile devices has the potential to further enhance the potential of mobile devices. One of the major challenges in this integration is the lack of an efficient service registry system that caters to issues associated with the dynamic and volatile mobile environments. Existing service registry technologies designed for traditional systems fall short of accommodating such issues. In this paper, we propose a novel approach to manage service registry systems provided 'solely' over mobile devices, and thus realising an SOA without the need for high-end computing systems. The approach manages a dynamic service registry system in the form of light weight and distributed registries. We assess the feasibility of our approach by engineering and deploying a working prototype of the proposed registry system over actual mobile devices. A comparative study of the proposed approach and the traditional UDDI (Universal Description, Discovery, and Integration) registry is also included. The evaluation of our framework has shown propitious results in terms of battery cost, scalability, hindrance with native applications.

cs.DC↗

A Novel Approach to Implement Message Level Security in RESTful Web Services

The world is rapidly adopting RESTful web services for most of its tasks. The once popular SOAP-based web services are fast losing ground owing to this. RESTful web services are light weight services without strict message formats. RESTful web services, unlike SOAP, are capable of message transfer in any format be it XML, JSON, plain text. However, in spite of these positives, ensuring message level security in REST is a challenge. Security in RESTful web services is still largely dependent upon transport layer security. There has been some work recently towards message level security in such environments wherein the transfer of message level security metadata is done through utilising new HTTP headers. We feel, however, that any method that compromises the generality of the HTTP protocol should be avoided. In this paper, therefore, we propose two new ways of encryption that promise to ensure message level security in RESTful web services without the need for special HTTP headers. This approach works seamlessly on most famous content-types of RESTful web services: XML, JSON, HTML, plain-text and various ASCII printable content types. Further, the proposed approach removes the need for content negotiation in cases where the content comprises XML, JSON, HTML, plain-text, and ASCII printable content types and also removes the need for XML or JSON canonicalization.

cs.NI↗

A Dynamic Service Description for Mobile Environments

With the increasing processing capability of mobile platforms and advancements in Internet of Things, modern mobile devices have shown a favorable prospect for on-the-go service provisioning. However, there is much to be done to realize this. A detailed, dynamic, and lightweight service description is an important requirement for automatic and efficient discovery, selection, and subsequent provisioning of services over mobile devices. Traditional approaches for service description are usually not directly adaptable to mobile environments owing to the latter's dynamic and distinct nature. In this paper, we propose a dynamic, lightweight, extensible, and detailed service description especially designed for mobile environments, considering crucial aspects such as isolated data source, collaborator partners, and hardware aspects along with the functional, non-functional, business, and contextual aspects. The description has been partitioned along these lines and various parts of the description are distributed between service registries and the mobile service providers. An up-to-date and light weight description has been achieved by this, without compromising on the overall consistency of the description. A prototype of the proposed system has been implemented with the intent of validating the feasibility of the approach. Further, the proposed approach is suitable for a heterogeneous environment comprising both wired and wireless systems.

cs.SE↗

SDO/AIA Observations of a Partially Erupting Prominence

We report an observation of a partially erupting prominence and associated dynamical plasma processes based on observations recorded by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The prominence first goes through a slow rise (SR) phase followed by a fast rise (FR). The slow rise phase started after a couple of small brightenings seen toward the footpoints. At the turning point from SR to FR, the prominence had already become kinked. The prominence shows strong brightening at the central kink location during the start of FR. We interpret this as internal magnetic reconnection occurring at a vertical current sheet forming between the two legs of the erupting prominence (flux-rope). The brightening at the central kink location is seen in all the EUV channels of AIA. The contributions of differential emission at higher temperatures are larger compared to that for typical coronal temperatures supporting a reconnection scenario at the central kink location. The plasma above the brightening location gets ejected as a hot plasmoid-like structure embedded in a CME, and those below drain down in the form of blobs moving towards the Sun's surface. The unique time resolution of the AIA has allowed all of these eruptive aspects, including SR-to-FR, kinking, central current sheet formation, plasmoid-like eruption, and filament "splitting", to be observed in a single event, providing strong and comprehensive evidence in favour of the model of partially erupting flux ropes.

astro-ph.SR↗

Motif Analysis in the Amazon Product Co-Purchasing Network

Online stores like Amazon and Ebay are growing by the day. Fewer people go to departmental stores as opposed to the convenience of purchasing from stores online. These stores may employ a number of techniques to advertise and recommend the appropriate product to the appropriate buyer profile. This article evaluates various 3-node and 4-node motifs occurring in such networks. Community structures are evaluated too.These results may provide interesting insights into user behavior and a better understanding of marketing techniques.

cs.SI↗