Supporting multiple isolation levels in replicated environments

Replication is used by databases to implement reliability and provide scalability. However, achieving transparent replication is not an easy task. A replicated database is transparent if it can seamlessly replace a standard stand-alone database without requiring any changes to the components of the system. Database replication transparency can be achieved if: (a) replication protocols remain hidden for all other components of the system; and (b) the functionality of a stand-alone database is provided. The ability to simultaneously execute transactions under different isolation levels is a functionality offered by all stand-alone databases but not by their replicated counterparts. Allowing different isolation levels may improve overall system performance. For example, the TPC-C benchmark specification tolerates execution of some transactions at weaker isolation levels in order to increase throughput of committed transactions. In this paper, we show how replication protocols can be extended to enable transactions to be executed under different isolation levels. © 2012 Elsevier B.V. All rights reserved.This work has been supported by the Spanish Ministerio de Ciencia e Innovation (MICINN) and the European Regional Development Fund (ERDF/FEDER) under research grants TIN2009-14460-C03-01 and TIN2010-17193. The translation of this paper was funded by the Universitat Politecnica de Valencia, Spain.Bernabe Gisbert, JM.; Muñoz Escoí, FD. (2012). Supporting multiple isolation levels in replicated environments. Data and Knowledge Engineering. 79-80:1-16. doi:10.1016/j.datak.2012.05.001S11679-8

Multilevel adaptive security system

Recent trends show increased demand for content-rich media such as images, videos and text in ad-hoc communication. Since such content often tends to be private, sensitive, or paid for, there exists a requirement for securing such information over resource constrained ad hoc networks. In this work, traditional data security mechanisms, existing ad hoc secure routing protocols and multilevel security are first reviewed. Then a new system, called the Multilevel Adaptive Security System, which incorporates the multilevel security concept at both the application layer and the network layer, is proposed to provide adaptive security services for data and routing processes. MLASS is composed of two subsystems: Content-Based Multi-level Data Security (CB-MLDS) for content-rich data protection and Multi-Level On-demand Secure Mobile Ad hoc Routing (MOSAR) for secure route selection. The structure of each sub-system is explained in detail; experiments for each sub-system were conducted and the performance was analyzed. It is shown that MLASS is a practical security solution that is flexible enough to adapt to a range of security requirements and applies appropriate level of security services to data and its distribution over ad hoc networks. MLASS provides a balance between security, performance and resource

Blockchain and Property Technology

Blockchain technology has emerged as a revolutionary force in the real estate sector, promis ing transformative changes in how properties are bought, sold, and managed. This study delves into the integration of blockchain in real estate, emphasizing the development and testing of a practical proof-of-concept application. The research, undertaken during an internship at DevScope, critically examines the potential of blockchain to enhance trans parency, security, and efficiency in managing exclusivity contracts. The research starts with a comprehensive review of blockchain literature, exploring its diverse applications within the real estate industry. It delves into the intricacies of challenges faced and opportunities presented during the implementation of blockchain technology in this context. Through rigorous analysis, the study assesses the profound impact of blockchain on the real estate landscape, elucidating the multifaceted benefits and challenges inherent in deploying blockchain-based solutions. Furthermore, this research not only contributes valuable insights to the ongoing discourse surrounding blockchain in real estate but also presents practical implications. The findings are poised to inform strategic decisions, providing DevScope with a nuanced perspective on integrating blockchain technology into their products. Specifically, this study evaluates the feasibility of incorporating a blockchain-based solution into MaxWork, one of DevScope’s products, thereby paving the way for innovative advancements within the realm of Multiple Listing Service solutions.A tecnologia Blockchain emergiu como uma força revolucionária no setor imobiliário, prom etendo mudanças na forma como as propriedades são transacionadas e geridas. Este estudo explora a integração da blockchain no setor imobiliário, a partir do desenvolvimento de uma aplicação de prova de conceito. A pesquisa, realizada durante um estágio na DevScope, examina o potencial da Blockchain para melhorar a transparência, segurança e eficiência nas transações imobiliárias. A pesquisa inicia-se com uma revisão da literatura sobre Blockchain e Distributed Ledger Technology (DLT), explorando as diversas aplicações dentro da indústria imobiliária. O estudo avalia o impacto da blockchain no cenário imobiliário, elucidando os benefícios e desafios inerentes à implementação de soluções baseadas em Blockchain. Além disso, esta pesquisa não só contribui com insights valiosos para o contínuo debate sobre Blockchain no setor imobiliário, como também apresenta implicações práticas. As descobertas deste estudo proporcionam à DevScope uma perspectiva detalhada sobre a integração da tecnologia Blockchain. Especificamente, este estudo avalia a viabilidade de incorporar uma solução baseada em Blockchain no MaxWork, um dos principais produtos da DevScope, abrindo caminho para avanços inovadores no âmbito dos Multiple Listing Services (MLS)

Flexible Transaction Dependencies in Database Systems

Numerous extended transaction models have been proposed in the literature to overcome the limitations of the traditional transaction model for advanced applications characterized by their long durations, cooperation between activities and access to multiple databases (like CAD/CAM and office automation). However, most of these extended models have been proposed with specific applications in mind and almost always fail to support applications with slightly different requirements.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44828/1/10619_2004_Article_270346.pd

The implementation and use of Ada on distributed systems with high reliability requirements

The general inadequacy of Ada for programming systems that must survive processor loss was shown. A solution to the problem was proposed in which there are no syntatic changes to Ada. The approach was evaluated using a full-scale, realistic application. The application used was the Advanced Transport Operating System (ATOPS), an experimental computer control system developed for a modified Boeing 737 aircraft. The ATOPS system is a full authority, real-time avionics system providing a large variety of advanced features. Methods of building fault tolerance into concurrent systems were explored. A set of criteria by which the proposed method will be judged was examined. Extensive interaction with personnel from Computer Sciences Corporation and NASA Langley occurred to determine the requirements of the ATOPS software. Backward error recovery in concurrent systems was assessed

Special Libraries, Winter 1986

Volume 77, Issue 1https://scholarworks.sjsu.edu/sla_sl_1986/1000/thumbnail.jp

Information Outlook, September 2005

Volume 9, Issue 9https://scholarworks.sjsu.edu/sla_io_2005/1008/thumbnail.jp

Communication Architecture For Distributed Interactive Simulation (CADIS): Military Standard (draft)

Report establishes the requirements for the communication architecture to be used in a distributed interactive simulation, including the standards and the recommended practices for implementing the communication architecture and the rationales behind them

The implementation and use of Ada on distributed systems with high reliability requirements

A preliminary analysis of the Ada implementation of the Advanced Transport Operating System (ATOPS), an experimental computer control system developed at NASA Langley for a modified Boeing 737 aircraft, is presented. The criteria that was determined for the evaluation of this approach is described. A preliminary version of the requirements for the ATOPS is contained. This requirements specification is not a formal document, but rather a description of certain aspects of the ATOPS system at a level of detail that best suits the needs of the research. The survey of backward error recovery techniques is also presented