Rituparna Chaki

Bio: Rituparna Chaki is an academic researcher from University of Calcutta. The author has contributed to research in topics: Routing protocol & Wireless sensor network. The author has an hindex of 16, co-authored 131 publications receiving 1514 citations. Previous affiliations of Rituparna Chaki include Calcutta Institute of Engineering and Management & Information Technology University.

CMS: Checkpoint-Based Multi-versioning System for Software Transactional Memory

Abstract: In this paper, we propose a novel checkpoint-based multi-versioning concurrency control system (CMS) for software transactional memory (STM). A checkpoint is defined to refer a set of versions. CMS maintains a list of live read-only transactions for every checkpoint. An appropriate object versioning technique decides on how many older versions are to be kept or to be removed. Moreover, the proposed method does not require any global synchronization point, such as centralized logical clock for versioning. Due to its efficient garbage-collecting mechanism, CMS is suitable for both read and write-dominated workload. We formally prove that CMS complies useless-prefix garbage collection (UP-GC). On the basis of number of memory accesses for searching consistent version, CMS performs better in comparison with conventional multi-version permissive STM.

Requirement-oriented risk management for incremental software development

Abstract: In incremental software development (ISD) functionalities are delivered incrementally and requirements keep on evolving across iterations. The requirements evolution involves the addition of new dependencies and conflicts among functional and non-functional requirements along with changes in priorities and dependency weights. This, in turn, demands refactoring the order of development of system components to minimize the impact of these changes. Neglecting the non-functional constraints in the software development process exposes it to risks that may accumulate across several iterations. In this research work, we propose a risk management framework for ISD processes that provides an estimate of risk exposure for the project when functional features are frozen while ignoring the associations with non-functional requirements. Our framework proposes suitable risk reduction strategies that work in tandem with the risk assessment module. We also provide a tool interface for our risk management framework.

Checkpoint based multi-version concurrency control mechanism for remote healthcare system

Abstract: This paper addresses the synchronization aspect for multiple concurrent threads in a Remote Healthcare System (RHS) under development. Resources like data files are shared by multiple stakeholders and users including doctors, trained paramedic staff, patient party or even Government agencies collecting statistical and demographic data. In the system under trial, medical kiosks are setup at distant places where patients visit and their complaints are recorded by trained caregivers. Later, doctor accesses such data from the system, makes a diagnosis and suggests prescriptions accordingly. In such a set-up, it is quite often that more than one users access the same shared resource simultaneously. In conventional lock-based process synchronization, such concurrent processes are blocked by the process holding a lock over the files. The major contribution of this paper is to use checkpoint-based multi-versioning Software Transactional Memory for our application domain to achieve non-blocking process synchronization. With help of multi-versioning technique the proposed method is also able to reduce number of expensive remote validations as well as transactional aborts. Experimental verification finds that proposed method yields higher throughput in comparison to clairvoyant type multi-version concurrency control mechanism.

CARO: A Conflict-Aware Requirement Ordering Tool for DevOps

Abstract: Requirement prioritization is an inherently important step in the DevOps framework. Unfortunately, the prioritization process often disregards the non-functional requirements and the possible conflicts among them. This implies that unresolved dependencies and conflicts would be identified at integration time only, which may lead to major refactoring issues. We introduce CARO a new tool that generates an ordering among the requirements based on conflicts and dependencies among the requirements. The tool provides a quantitative risk evaluation framework along with risk mitigation strategies based on conflicts and dependencies among the requirements.

PORs: Proofs of Retrievability for Large Files

Abstract: In this paper, we define and explore proofs of retrievability (PORs). A POR scheme enables an archive or back-up service (prover) to produce a concise proof that a user (verifier) can retrieve a target file F, that is, that the archive retains and reliably transmits file data sufficient for the user to recover F in its entirety.A POR may be viewed as a kind of cryptographic proof of knowledge (POK), but one specially designed to handle a large file (or bitstring) F. We explore POR protocols here in which the communication costs, number of memory accesses for the prover, and storage requirements of the user (verifier) are small parameters essentially independent of the length of F. In addition to proposing new, practical POR constructions, we explore implementation considerations and optimizations that bear on previously explored, related schemes.In a POR, unlike a POK, neither the prover nor the verifier need actually have knowledge of F. PORs give rise to a new and unusual security definition whose formulation is another contribution of our work.We view PORs as an important tool for semi-trusted online archives. Existing cryptographic techniques help users ensure the privacy and integrity of files they retrieve. It is also natural, however, for users to want to verify that archives do not delete or modify files prior to retrieval. The goal of a POR is to accomplish these checks without users having to download the files themselves. A POR can also provide quality-of-service guarantees, i.e., show that a file is retrievable within a certain time bound.