Learn More
We evaluate the performance of voice transmission over a single-AP WLAN analytically and via simulation. Given the parameters of the medium access control protocol and different voice codecs, the voice capacity of the WLAN, in terms of the maximum number of voice connections that can be supported by the WLAN with satisfactory user-perceived quality, is(More)
With the popularity of the IEEE 802.11 standards, many analytical saturation throughput studies for the distributed coordination function (DCF) have been reported. In this paper, we outline a number of issues and criticalities raised by previously proposed models. In particular, a careful look at backoff counter decrement rules allows us to conclude that,(More)
Botnets become widespread in wired and wireless networks, whereas the relevant research is still in the initial stage. In this paper, a survey of botnets is provided. We first discuss fundamental concepts of botnets, including formation and exploitation, lifecycle, and two major kinds of topologies. Several related attacks, detection, tracing, and(More)
Radio frequency identification (RFID) systems can identify an object or a person using wireless transmission. An RFID system consists of RFID tags (also called transponders) and readers (also called interrogators). Readers broadcast queries to tags in their wireless transmission ranges for information contained in tags, and tags reply with required(More)
This study developed a method for analysis of nineteen quinolone and fluoroquinolone antibiotics (FQs) in sludge samples, and investigated the occurrence and fate of the FQs in a municipal sewage treatment plant (STP) with anaerobic, anoxic, and aerobic treatment processes. Eleven compounds, including pipemidic acid, fleroxacin, ofloxacin, norfloxacin,(More)
People enjoy the convenience of on-line services, but online environments may bring many risks. In this paper, we discuss how to prevent users’ passwords from being stolen by adversaries. We propose a virtual password concept involving a small amount of human computing to secure users’ passwords in on-line environments. We adopt user-determined randomized(More)
BACKGROUND AND PURPOSE Adipocyte fatty acid-binding protein (A-FABP) is up-regulated in regenerated endothelial cells and modulates inflammatory responses in macrophages. Endothelial dysfunction accompanying regeneration is accelerated by hyperlipidaemia. Here, we investigate the contribution of A-FABP to the pathogenesis of endothelial dysfunction in the(More)
In wireless sensor networks, some sensor nodes are put in sleep mode while other sensor nodes are in active mode for sensing and communication tasks in order to reduce energy consumption and extend network lifetime. This approach is a special case (k 1⁄4 2) of a randomized scheduling algorithm, in which k subsets of sensors work alternatively. In this(More)
Voice over Internet Protocol (VoIP) is one of the fastest growing Internet applications. It is a viable alternative to the traditional telephony systems due to its high resource utilization and cost efficiency. Meanwhile, Wireless Local Area Networks (WLANs) have become a ubiquitous networking technology that has been deployed around the world. Driven by(More)