This paper proposes a lightweight, fast and efficient method for the detection of jamming attacks, interference, and other anomalies in electronic shelf label (ESL) systems and wireless sensor networks (WSNs) with periodic data transmission. The proposed method is based on the thresholding technique, which is applied to selected parameters of traffic and allows discrimination of random failures from anomalies and intrusions. It does not require the installation of additional hardware and does not create extra communication costs; its computational requirements are negligible, since it is based on statistical methods. Herein recommendations are provided for choosing a thresholds type. Extensive simulations, made by Castalia simulator for WSNs, show that the proposed method has superior accuracy compared to existing algorithms.

This paper proposes a reliable data aggregation scheduling that uses caching and re-transmission based on track topology. In the proposed scheme, a node detects packet losses by overhearing messages that includes error indications of the child nodes, from its neighbor nodes. If packet losses are detected, as a backup parent, the node retransmits the lost packet. A retransmission strategy is added into the adaptive timeout scheduling scheme, which adaptively configures both the timeout and the collection period according to the potential level of an event occurrence. The retransmission steps cause an additional delay and power consumption of the sensor nodes, but dramatically increase the data accuracy of the aggregation results. An extensive simulation under various workloads shows that the proposed scheme outperforms other schemes in terms of data accuracy and energy consumption.

A parallel file system is normally used to support excessive file requests from parallel applications in a cluster system, whereas prefetching is useful for improving the file system performance. This paper proposes dynamic file prefetching scheme based on file access patterns, named table-comparison prefetching policy, that is particularly suitable for parallel scientific applications and multimedia web services in a VIA-based parallel file system. VIA relieves the communication overhead of traditional communication protocols, such as TCP/IP. The proposed policy introduces a table-comparison method to predict data for prefetching. In addition, it includes an algorithm to determine whether and when prefetching is performed using the current available I/O bandwidth. Experimental results confirmed that the use of the proposed prefetching policy in a VIA-based parallel file system produced a higher file system performance for various file access patterns.

Wireless sensor networks are subject to node and link failures for a variety of reasons. This paper proposes a k-disjoint-path routing algorithm that varies the number of disjoint paths (k) in order to meet a target-delivery ratio of critical events and to reduce energy consumption. The proposed algorithm sends packets to the base station through a single path without the occurrence of critical events, however, it sends packets to the base station through k disjoint paths (k>1) under the occurrence of critical events, where k is computed from a well-defined fault model. The proposed algorithm detects the occurrence of critical events by monitoring collected data patterns. The simulation results reveal that the proposed algorithm is more resilient to random node failure and patterned failure than other routing algorithms, and it also decreases energy consumption much more than the multi-path and path-repair algorithms.

This paper proposes a novel routing algorithm that constructs position-based k-disjoint paths to realize greater resiliency to patterned failure. The proposed algorithm constructs k-disjoint paths that are spatially distributed by using the hop-count based positioning system. Simulation results reveal that the proposed algorithm is more resilient to patterned failure than other routing algorithms, while it has low power consumption and small delay.

In this paper, we propose a novel in-network aggregation scheduling scheme for forest fire monitoring in a wireless sensor network. This adaptively configures both the timeout and the collecting period according to the potential level of a fire occurrence. At normal times, the proposed scheme decreases a timeout that is a wait time for packets sent from child nodes and makes the collecting period longer. That reduces the dissipated energy of the sensor node. Conversely, the proposed scheme increases the timeout and makes the collecting period shorter during fire occurrences in order to achieve more accurate data aggregation and early fire detection.

Recently, the need for multimedia devices, such as mobile phones, digital TV, PMP, digital camcorders, digital cameras has increased. These devices provide various services for multimedia file manipulation, allowing multimedia contents playback, multimedia file editing, etc. Additionally, digital TV provides a recorded multimedia file copy to a portable USB disk. However, Linux Ext3 file system, as employed by these devices, has a lot of drawbacks, as it required a considerable amount of time and disk I/Os to store large-size edited multimedia files, and it is hard to access for typical PC users. Therefore, in this paper a design and implementation of an amortized Ext3 with FWAE (Fast Writing-After-Editing) for WinXP-based multimedia applications is described. The FWAE is a fast and efficient multimedia file editing/storing technique for the Ext3 that exploits inode block pointer re-setting and shared data blocks by simply modifying metadata information. Individual experiments in this research show that the amortized Ext3 with FWAE for WinXP not only dramatically improves written performance of the Ext3 by 16 times on average with various types of edited multimedia files but also notably reduces the amount of consumed disk space through data block sharing. Also, it provides ease and comfort to use for typical PC users unfamiliar with Linux OS.