We present a new protocol for maintaining replicated data that can provide both high data availability and low response time. In the protocol, the nodes are organized in a logical grid. Existing protocols are designed primarily to achieve high availability by updating a large fraction of the copies which provides some (although not signiicant) load sharing. In the new protocol, transaction proc...

When modeling fault-tolerant systems, state-based methods yield much more realistic results in comparison to traditional combinatorial methods. To avoid the difficult manual design of large state-based models, we advocate an approach, by which a high-level input model is used from which a semantically equivalent low-level model is automatically generated. This approach was implemented in the to...

Renal oxygen tension is substantially lower in the medulla than in the cortex and is reduced in hypertensive rats, a model of oxidative stress. Expression of NADPH oxidase, the primary source for superoxide anion (O(2)(-)*) in the kidney, is elevated in hypertension. Because molecular oxygen (O(2)) is required for O(2)(-)* formation, we tested the hypothesis that renal NADPH oxidase activity is...

Inventory models in which the demand rate depends on the inventory level are based on the common real-life observation that greater product availability tends to stimulate more sales. Previous models incorporating inventory-level dependent demand rate assume that the holding cost is constant for the entire inventory cycle. This paper considers the inventory policy for an item with a stock-level...

Several studies on photovoltaic systems focused on how it operates and energy required in operating it. Little attention is paid on its configurations, modeling of mean time to system failure, availability, cost benefit and comparisons of parallel and series–parallel designs. In this research work, four system configurations were studied. Configuration I consists of two sub-components arranged ...