Achieving Starvation-Freedom with Greater Concurrency in Multi-Version Object-based Transactional Memory Systems

To utilize the multi-core processors properly concurrent programming is needed. Concurrency control is the main challenge while designing a correct and efficient concurrent program. Software Transactional Memory Systems (STMs) provides ease of multithreading to the programmer without worrying about concurrency issues such as deadlock, livelock, priority inversion, etc. Most of the STMs works on read-write operations known as RWSTMs. Some STMs work at high-level operations and ensure greater concurrency than RWSTMs. Such STMs are known as Object-Based STMs (OSTMs). The transactions of OSTMs can return commit or abort. Aborted OSTMs transactions retry. But in the current setting of OSTMs, transactions may starve. So, we proposed a Starvation-Free OSTM (SF-OSTM) which ensures starvation-freedom in object based STM systems while satisfying the correctness criteria as co-opacity. Databases, RWSTMs and OSTMs say that maintaining multiple versions corresponding to each key of transaction reduces the number of aborts and improves the throughput. So, to achieve greater concurrency, we proposed Starvation-Free Multi-Version OSTM (SF-MVOSTM) which ensures starvation-freedom while storing multiple versions corresponding to each key and satisfies the correctness criteria such as local opacity. To show the performance benefits, We implemented three variants of SF-MVOSTM (SF-MVOSTM, SF-MVOSTM-GC and SF-KOSTM) and compared it with state-of-the-art STMs.Comment: 68 pages, 24 figures. arXiv admin note: text overlap with arXiv:1709.0103

A generic persistence model for CLP systems (and two useful implementations)

This paper describes a model of persistence in (C)LP languages and two different and practically very useful ways to implement this model in current systems. The fundamental idea is that persistence is a characteristic of certain dynamic predicates (Le., those which encapsulate state). The main effect of declaring a predicate persistent is that the dynamic changes made to such predicates persist from one execution to the next one. After proposing a syntax for declaring persistent predicates, a simple, file-based implementation of the concept is presented and some examples shown. An additional implementation is presented which stores persistent predicates in an external datábase. The abstraction of the concept of persistence from its implementation allows developing applications which can store their persistent predicates alternatively in files or databases with only a few simple changes to a declaration stating the location and modality used for persistent storage. The paper presents the model, the implementation approach in both the cases of using files and relational databases, a number of optimizations of the process (using information obtained from static global analysis and goal clustering), and performance results from an implementation of these ideas

Administrative Profiles Unit and Multi-Sessions Management Scheme for IPBrick Private Cloud

IPBrick solution for the Private Cloud has some limitations which can be challenged in future by its competitors in the market. The administrative access to the web interface of an IPBrick server is restricted to one user who manages everything by using a given set of features and services. The existing solution also does not support Multi-Sessions Management due to which multiple update operations can't be applied on the database simultaneously and if it is attempted then it can have adverse affects on the consistency of data stored in the Database. The aim of this thesis is to develop features like Administrative Profiles and Multi-Sessions Management for the betterment of IPBrick Solution

FLORIDA\u27S DOWNTOWNS: THE KEY TO SMART GROWTH, URBAN REVITALIZATION, AND GREEN SPACE PRESERVATION

This article reviews Florida\u27s growth management system, which has spurred suburban development, and its negative impact on Florida\u27s cities. As Florida\u27s governor and legislature have turned their focus to this issue, this article evaluates policy recommendations to limit Florida\u27s suburban sprawl and invigorate its urban centers

An Optimistic Mandatory Access Control Model for Distributed Collaborative Editors

Distributed Collaborative Editors (DCE) provide computer support for modifying simultaneously shared documents, such as articles, wiki pages and programming source code, by dispersed users. Controlling access in such systems is still a challenging problem, as they need dynamic access changes and low latency access to shared documents. In this paper, we propose a Mandatory Access Control (MAC) based on replicating the shared document and its authorization policy at the local memory of each user. To deal with latency and dynamic access changes, we use an optimistic access control technique where enforcement of authorizations is retroactive. We show that naive coordination between updates of both copies can create security hole on the shared document by permitting illegal modification, or rejecting legal modification. Finally, we present a novel framework for managing authorizations in collaborative editing work which may be deployed easily on P2P networks