Abhishek Srivastava

Seemandhar Jain, Prarthi Jain, Abhishek Srivastava

Anomaly detection is critical in various fields, including intrusion detection, health monitoring, fault diagnosis, and sensor network event detection. The isolation forest (or iForest) approach is a well-known technique for detecting anomalies. It is, however, ineffective when dealing with dynamic streaming data, which is becoming increasingly prevalent in a wide variety of application areas these days. In this work, we extend our previous work by proposed an efficient iForest based approach for anomaly detection using cube sampling that is effective on streaming data. Cube sampling is used in the initial stage to choose nearly balanced samples, significantly reducing storage requirements while preserving efficiency. Following that, the streaming nature of data is addressed by a sliding window technique that generates consecutive chunks of data for systematic processing. The novelty of this paper is in applying Cube sampling in iForest and calculating inclusion probability. The proposed approach is equally successful at detecting anomalies as existing state-of-the-art approaches, requiring significantly less storage and time complexity. We undertake empirical evaluations of the proposed approach using standard datasets and demonstrate that it outperforms traditional approaches in terms of Area Under the ROC Curve (AUC-ROC) and can handle high-dimensional streaming data.

Gyan Prakash Tiwary, Abhishek Srivastava

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.

Rohit Verma, Abhishek Srivastava

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.