Search

The rapid rate of change in the computing and engineering domains has our educational institutions on high alert. The authors explore how best to prepare graduates for a world in which cyber-physical systems are increasingly ubiquitous. [ABSTRACT FROM PUBLISHER]

The article focuses on opportunities and obligations for physical computing systems. Seamlessly integrating computing with the physical world via sensors and actuators, physical computing systems promise to give society an improved living standard, greater security, and unparalleled convenience and efficiency. To better understand physical computing's advantages, this article gives emphasis on three application areas. These include assisted living, emergency response systems for natural or man-made disasters, and protecting critical infrastructures at the national level.

This paper describes a multistep technique that can be applied to improve system structure and to improve performance when necessary. The technique begins with the analysis of system structure via the structured design guidelines of coupling and cohesion. Next, manual system structure improvement transformations am applied. The effect of the transformations on execution time is then determined. Finally, vertical migration is used on the restructured system to improve its performance. Using the results of this paper, system programmers can identify specific cases where both good system structure and good performance are attainable, and others where tradeoffs must be made. The technique is most applicable during the maintenance phase of the software life cycle. [ABSTRACT FROM AUTHOR]

The demand for real-time data services is increasing in many applications including e-commerce, agile manufacturing, and telecommunications network management. In these applications, it is desirable to execute transactions within their deadlines, i.e., before the real-world status changes, using fresh (temporally consistent) data. However, meeting these fundamental requirements is challenging due to dynamic workloads and data access patterns in these applications. Further, transaction timeliness and data freshness requirements may conflict. In this paper, we define average/transient deadline miss ratio and new data freshness metrics to let a database administrator specify the desired quality of real-time data services for a specific application. We also present a novel QoS management architecture for real-time databases to support the desired QoS even in the presence of unpredictable workloads and access patterns. To prevent overload and support the desired QoS, the presented architecture applies feedback control, admission control, and flexible freshness management schemes. A simulation study shows that our QoS-aware approach can achieve a near zero miss ratio and perfect freshness, meeting basic requirements for real-time transaction processing. In contrast, baseline approaches fail to support the desired miss ratio and/or freshness in the presence of unpredictable workloads and data access patterns. [ABSTRACT FROM AUTHOR]

This paper, presents a modified priority based probe algorithm for deadlock detection and resolution in distributed database systems. The original priority based probe algorithm was presented by Sinha and Natarajan based on work by Chandy, Misra, and Haas. Various examples are used to show that the original priority based algorithm either fails to detect deadlocks or reports deadlocks which do not exist in many situations. A modified algorithm which eliminates these problems is proposed. This algorithm has been tested through simulation and appears to be error free. Finally, the performance of the modified algorithm is briefly discussed. [ABSTRACT FROM AUTHOR]

Presents a correction to a publishing error in the paper "A Modified Priority Based Probe Algorithm for Distributed Deadlock Detection and Resolution," by Alok N. Choudhary et al.