Economic aspects of pharmacotherapy for chronic constipation

Constipation is one of the most common digestive complaints. It is a symptom, not a disease. The subjectivity that this involves means that assessments of clinical epidemiology, socioeconomic costs and pharmacotherapy are difficult, since there is no definition of 'normal' bowel habit. Although constipation can affect all ages, the problem increases with age, and is of particular concern for those who are frail and in long term care. Cultural influences may affect the prevalence in older people. Drug therapy of constipation cannot be considered in isolation, since there are issues in the prevention of constipation and the principles of good management that also apply. Furthermore, some consideration of the pathophysiology and diagnosis is important. This is because a number of remediable causes can be identified, and the diagnostic process involves patient education, which in turn may be effective in reducing costs. It is the complaint of constipation which leads either to self-medication or to consultation with the medical profession. Both of these courses of action have a significant influence on utilisation of laxatives (cathartics), obtained both over-the-counter and by prescription. Although there are a large number of laxative preparations available, therapy has changed little in half a century. Costs may vary considerably, and with such a significant problem there is a need for comparative studies. However, study methodologies are difficult, and a significant placebo response may be found. Education and preventive measures have been shown to reduce laxative use and costs in institutions. Unfortunately, there are few comparative studies of individual laxatives and even fewer cost-effectiveness studies. Those that there are have been based in institutions, and so extrapolation to other situations may be difficult. In general, little attention is given to constipation. It is, however, an area with significant resource implications in which education and preventive measures have been shown to be beneficial. Even so, there is still a need for good comparative studies, particularly where cost effectiveness is concerned.

The Use of Audio Podcasts to Enhance the Delivery of a Computer Networks Course

Experience obtained in the support of mobile learning using podcast audio is reported. The paper outlines design, storage and distribution via a web site. An initial evaluation of the uptake of the approach in a final year computing module was undertaken. Audio objects were tailored to meet different pedagogical needs resulting in a repository of persistent glossary terms and disposable audio lectures distributed by podcasting. An aim of our approach is to document the interest from the students, and evaluate the potential of mobile learning for supplementing revision

Detecting stealthy attacks: Efficient monitoring of suspicious activities on computer networks

Stealthy attackers move patiently through computer networks - taking days, weeks or months to accomplish their objectives in order to avoid detection. As networks scale up in size and speed, monitoring for such attack attempts is increasingly a challenge. This paper presents an efficient monitoring technique for stealthy attacks. It investigates the feasibility of proposed method under number of different test cases and examines how design of the network affects the detection. A methodological way for tracing anonymous stealthy activities to their approximate sources is also presented. The Bayesian fusion along with traffic sampling is employed as a data reduction method. The proposed method has the ability to monitor stealthy activities using 10-20% size sampling rates without degrading the quality of detection.

The Non-Responsive Receiver Problem in Mobile Ad-hoc Networks

This letter exposed a serious unfairness problem with IEEE 802.11 MAC based Mobile Ad-hoc Networks (MANETs) when operating TCP connections, and identifies the three common factors that contribute to this problem. The work initiated the development of a programmable wireless framework that is subsequently used in a spin-out company (TOM), and by the Telecoms Technology Testing centre in Taiwan(Dr D Chieng).

WFI Optimised PWGPS for Wireless IP Networks

The paper describes the design and analysis of a packet scheduler intended to operate over wireless channels with spatially selective error bursts. A particularly innovative aspect in the design is the optimization of the scheduler algorithm to minimize the worst-case fairness index (WFI) for real-time IP traffic.

Efficient Path Key Establishment For Wireless Sensor Networks

Key pre-distribution schemes have been proposed as means to overcome Wireless Sensor Networks constraints such as limited communication and processing power. Two sensor nodes can establish a secure link with some probability based on the information stored in their memories though it is not always possible that two sensor nodes may set up a secure link. In this paper, we propose a new approach that elects trusted common nodes called ”Proxies” which reside on an existing secure path linking two sensor nodes. These sensor nodes are used to send the generated key which will be divided into parts (nuggets) according to the number of elected proxies. Our approach has been assessed against previously developed algorithms and the results show that our algorithm discovers proxies more quickly which are closer to both end nodes, thus producing shorter path lengths. We have also assessed the impact of our algorithm on the average time to establish a secure link when the transmitter and receiver of the sensor nodes are ”ON”. The results show the superiority of our algorithm in this regard. Overall, the proposed algorithm is well suited for Wireless Sensor Networks.

Accurate available bandwidth estimation in IEEE 802.11-based ad hoc networks

Quality of Service (QoS) support in IEEE 802.11-based ad hoc networks relies on the networks’ ability to estimate the available bandwidth on a given link. However, no mechanism has been standardized to accurately evaluate this resource. This remains one of the main issues open to research in this field. This paper proposes an available bandwidth estimation approach which achieves more accurate estimation when compared to existing research. The proposed approach differentiates the channel busy caused by transmitting or receiving from that caused by carrier sensing, and thus improves the accuracy of estimating the overlap probability of two adjacent nodes’ idle time. Simulation results testify the improvement of this approach when compared with well known bandwidth estimation methods in the literature.

Periodic FDTD analysis of a 2-D leaky-wave planar antenna based on dipole frequency selective surfaces

A periodic finite-difference time-domain (FDTD) analysis is presented and applied for the first time in the study of a two-dimensional (2-D) leaky-wave planar antenna based on dipole frequency selective surfaces (FSSs). First, the effect of certain aspects of the FDTD modeling in the modal analysis of complex waves is studied in detail. Then, the FDTD model is used for the dispersion analysis of the antenna of interest. The calculated values of the leaky-wave attenuation constants suggest that, for an antenna of this type and moderate length, a significant amount of power reaches the edges of the antenna, and thus diffraction can play an important role. To test the validity of our dispersion analysis, measured radiation patterns of a fabricated prototype are presented and compared with those predicted by a leaky-wave approach based on the periodic FDTD results.

An Antennas and Propagation Approach to Improving Physical Layer Performance in Wireless Body Area Networks

A combined antennas and propagation study has been undertaken with a view to directly improving link conditions for wireless body area networks. Using tissue-equivalent numerical and experimental phantoms representative of muscle tissue at 2.45 GHz, we show that the node to node [S-21] path gain performance of a new wearable integrated antenna (WIA) is up to 9 dB better than a conventional compact Printed-F antenna, both of which are suitable for integration with wireless node circuitry. Overall, the WIA performed extremely well with a measured radiation efficiency of 38% and an impedance bandwidth of 24%. Further benefits were also obtained using spatial diversity, with the WIA providing up to 7.7 dB of diversity gain for maximal ratio combining. The results also show that correlation was lower for a multipath environment leading to higher diversity gain. Furthermore, a diversity implementation with the new antenna gave up to 18 dB better performance in terms of mean power level and there was a significant improvement in level crossing rates and average fade durations when moving from a single-branch to a two-branch diversity system.

A programmable architecture for layered multimedia streams in IPv6 networks

A new configurable architecture is presented that offers multiple levels of video playback by accommodating variable levels of network utilization and bandwidth. By utilizing scalable MPEG-4 encoding at the network edge and using specific video delivery protocols, media streaming components are merged to fully optimize video playback for IPv6 networks, thus improving QoS. This is achieved by introducing “programmable network functionality” (PNF) which splits layered video transmission and distributes it evenly over available bandwidth, reducing packet loss and delay caused by out-of-profile DiffServ classes. An FPGA design is given which gives improved performance, e.g. link utilization, end-to-end delay, and that during congestion, improves on-time delivery of video frames by up to 80% when compared to current “static” DiffServ.

The absence of creativity in Feist and the computational process

The decision of the U.S. Supreme Court in 1991 in Feist Publications, Inc. v. Rural Tel. Service Co. affirmed originality as a constitutional requirement for copyright. Originality has a specific sense and is constituted by a minimal degree of creativity and independent creation. The not original is the more developed concept within the decision. It includes the absence of a minimal degree of creativity as a major constituent. Different levels of absence of creativity also are distinguished, from the extreme absence of creativity to insufficient creativity. There is a gestalt effect of analogy between the delineation of the not original and the concept of computability. More specific correlations can be found within the extreme absence of creativity. "[S]o mechanical" in the decision can be correlated with an automatic mechanical procedure and clauses with a historical resonance with understandings of computability as what would naturally be regarded as computable. The routine within the extreme absence of creativity can be regarded as the product of a computational process. The concern of this article is with rigorously establishing an understanding of the extreme absence of creativity, primarily through the correlations with aspects of computability. The understanding established is consistent with the other elements of the not original. It also revealed as testable under real-world conditions. The possibilities for understanding insufficient creativity, a minimal degree of creativity, and originality, from the understanding developed of the extreme absence of creativity, are indicated. 

A distributed contention-vector division multiple access (D-CVDMA) protocol for wireless networks

Traditional Time Division Multiple Access (TDMA) protocol provides deterministic periodic collision free data transmissions. However, TDMA lacks flexibility and exhibits low efficiency in dynamic environments such as wireless LANs. On the other hand contention-based MAC protocols such as the IEEE 802.11 DCF are adaptive to network dynamics but are generally inefficient in heavily loaded or large networks. To take advantage of the both types of protocols, a D-CVDMA protocol is proposed. It is based on the k-round elimination contention (k-EC) scheme, which provides fast contention resolution for Wireless LANs. D-CVDMA uses a contention mechanism to achieve TDMA-like collision-free data transmissions, which does not need to reserve time slots for forthcoming transmissions. These features make the D-CVDMA robust and adaptive to network dynamics such as node leaving and joining, changes in packet size and arrival rate, which in turn make it suitable for the delivery of hybrid traffic including multimedia and data content. Analyses and simulations demonstrate that D-CVDMA outperforms the IEEE 802.11 DCF and k-EC in terms of network throughput, delay, jitter, and fairness.