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Physical Sciences and Mathematics Commons

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Full-Text Articles in Physical Sciences and Mathematics

Checkpointing And Recovery In Distributed And Database Systems, Jiang Wu Jan 2011

Checkpointing And Recovery In Distributed And Database Systems, Jiang Wu

Theses and Dissertations--Computer Science

A transaction-consistent global checkpoint of a database records a state of the database which reflects the effect of only completed transactions and not the re- sults of any partially executed transactions. This thesis establishes the necessary and sufficient conditions for a checkpoint of a data item (or the checkpoints of a set of data items) to be part of a transaction-consistent global checkpoint of the database. This result would be useful for constructing transaction-consistent global checkpoints incrementally from the checkpoints of each individual data item of a database. By applying this condition, we can start from any useful checkpoint of …


A Secure Online Payment System, Shristi Pant Jan 2011

A Secure Online Payment System, Shristi Pant

Theses and Dissertations--Computer Science

An online payment system allows a customer to make a payment to an online merchant or a service provider. Payment gateways, a channel between customers and payment processors, use various security tools to secure a customer’s payment information, usually debit or credit card information, during an online payment. However, the security provided by a payment gateway cannot completely protect a customer’s payment information when a merchant also has the ability to obtain the payment information in some form. Furthermore, not all merchants provide a secure payment environment to their customers and, despite having a standard payment policy, adhere to it. …