The control of sea lice in Atlantic salmon by selective breeding

Sea lice threaten the welfare of farmed Atlantic salmon and the sustainability of fish farming across the world. Chemical treatments are the major method of control but drug resistance means that alternatives are urgently needed. Selective breeding can be a cheap and effective alternative. Here, we combine experimental trials and diagnostics to provide a practical protocol for quantifying resistance to sea lice. We then combined quantitative genetics with epidemiological modelling to make the first prediction of the response to selection, quantified in terms of reduced need for chemical treatments. We infected over 1400 young fish with Lepeophtheirus salmonis, the most important species in the Northern Hemisphere. Mechanisms of resistance were expressed early in infection. Consequently, the number of lice per fish and the ranking of families were very similar at 7 and 17 days post infection, providing a stable window for assessing susceptibility to infection. The heritability of lice numbers within this time window was moderately high at 0.3, confirming that selective breeding is viable. We combined an epidemiological model of sea lice infection and control on a salmon farm with genetic variation in susceptibility among individuals. We simulated 10 generations of selective breeding and examined the frequency of treatments needed to control infection. Our model predicted that substantially fewer chemical treatments are needed to control lice outbreaks in selected populations and chemical treatment could be unnecessary after 10 generations of selection. Selective breeding for sea lice resistance should reduce the impact of sea lice on fish health and thus substantially improve the sustainability of Atlantic salmon production.     

Application of neural networks and machine learning in networkdesign

Communication network design is becoming increasingly complex, involving making networks more usable, affordable, and reliable. To help with this, we have proposed an expert network designer (END) for configuring, modeling, simulating, and evaluating large structured computer networks, employing artificial intelligence, knowledge representation, and network simulation tools. We present a neural network/knowledge acquisition machine-learning approach to improve the END's efficiency in solving the network design problem and to extend its scope to acquire new networking technologies, learn new network design techniques, and update the specifications of existing technologies     

FlowMate: scalable on-line flow clustering

We design and implement an efficient on-line approach, FlowMate, for clustering flows (connections) emanating from a busy server, according to shared bottlenecks. Clusters can be periodically input to load balancing, congestion coordination, aggregation, admission control, or pricing modules. FlowMate uses in-band (passive) end-to-end delay measurements to infer shared bottlenecks. Delay information is piggybacked on feedback from the receivers, or, if impossible, TCP or application round-trip time estimates are used. We simulate FlowMate and examine the effects of network load, traffic burstiness, network buffer sizes, and packet drop policies on clustering correctness, evaluated via a novel accuracy metric. We find that coordinated congestion management techniques are more fair when integrated with FlowMate. We also implement FlowMate in the Linux kernel v2.4.17 and evaluate its performance on the Emulab testbed, using both synthetic and tcplib-generated traffic. Our results demonstrate that clustering of medium to long-lived flows is accurate, even with bursty background traffic. Finally, we validate our results on the Internet Planetlab testbed.     

On the determination of boundaries to manipulator workspaces

The accumulation of two independent, broadly applicable formulations for determining the boundary to manipulator workspaces, presented elsewhere, are compared in this paper. Insights gained from one method are used to explain behavior exhibited in the other. Results are also compared and validated. A numerical formulation based on continuation methods is used to map curves that are on the boundary of a manipulator workspace. Analytical criteria based on row rank deficiency criteria of the manipulator's analytical Jacobian are used to map a family of one-dimensional solution curves on the boundary. The other formulation, based on a similar rank-deficiency criteria, yields analytic boundaries parametrized in terms of surface patches on the boundary. Results concerning the applicability of the numerical method to open- and closed-loop systems are compared with those limited to the open-loop for the analytical method. Conclusions regarding the behavior of the manipulator on geometric entities characterized by singular curves, higher-order bifurcation points, and surfaces inside the workspace are drawn. Applicability of both methods and their limitations are also addressed.     

Evaluation of a proper controller performance for maximum-power point tracking of a stand-alone PV system

In this paper the implementation of a suggested stand-alone PV system, for maximum-power point tracking (MPPT), is carried out. Also, this paper presents a comparative study, through experimental work, between the conventional PI controller and the fuzzy logic controller (FLC) under different atmospheric conditions. The implemented system with both the PI controller and the FLC gives a good maximum-power operation of the PV array, but the tracking capability for different optimum operating points is better and faster for the case of using the FLC compared to the case of using the PI controller.     

Multi-User MIMO Mobile CDMA Uplink System Employing Turbo Coding and Joint Detection Through a Multipath Rayleigh Fading Channel

In this paper, a generalized multiple-input multiple-output (MIMO) antenna system that can be fitted to the uplink of a wireless communication system is considered for the general case of multi-user. At the transmitter, the information bits are Turbo coded, then interleaved and passed through a serial-to-parallel converter. The channel is assumed bad urban suffering from multipath Rayleigh fading resulting in inter-symbol and multiple access interferences (ISI and MAI). At the front-end of the receiver, a number of receiving antennas are used followed by a joint multi-user estimator based on the Minimum Mean Square Error Block Linear Equalizer (MMSE-BLE).Computer simulations demonstrate a significant performance improvement in both single user and multi-user cases.This paper depends in parts on that presented at the 11th European Wireless Conference, Cyprus, Nicosia, pp. 187–192, April 2005. Yasmine A. Fahmy was born in Guiza, Egypt, on June 4, 1976. She received the B.Sc., M.Sc. and Ph.D. degrees in Communication and Electronics engineering from Cairo University, Egypt on 1999, 2001 and 2005 respectively. She is presently an assistant professor at Cairo University, Egypt. Her current field of interest is wireless communication and channel estimation. Hebat-Allah M. Mourad received her B.Sc., M. Sc. and Ph.D. degrees in electrical communication engineering from Cairo University, Egypt, in 1983, 1987 and 1994 respectively. Since 1983, she has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently associate professor there. Her research interests include optical fiber communications, mobile and satellite communications. Emad K. Al-Hussaini received his B.Sc degree in Electrical Communication Engineering from Ain-Shams University, Cairo, Egypt, in 1964 and his M.Sc and Ph.D. degrees from Cairo University, Giza, Egypt, in 1974 and 1977, respectively. From 1964 to 1970, he was with the General Egyptian Aeroorganization. Since 1970, he has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently professor there. He was a research fellow at Imperial College, London, UK, and at the Moore School of Electrical Engineering, University of Pennsylvania, Philadelphia, PA, USA, in the academic years 1976/1977 and 1981/1982, respectively. In 1990, he received the Egyptian national encouragement award for outstanding engineering research. He has written several papers for technical international journals and conferences. His research interests include signal processing, fading channel communication, modulation, and cellular mobile radio systems. Dr Al-Hussaini is a senior member of IEEE. He is listed in Marquis Whos Who in the World and in the IBC (International Biographical Center, Cambridge) for outstanding people of the 20th century.     

The sinuous antenna-A dual polarized feed for reflector-based searching systems

The sinuous antennas have a numerous applications in military and civil systems such as direction finding systems and reflector feeds due to their superior broadband characteristics and simultaneous polarization capability. In this paper, design, construction and measurements of planar sinuous antennas are investigated for 1–5 GHz frequency range. Feeding sections of this antenna are realized by using microstrip tapered baluns. We have determined the microstrip tapered balun dimensions using Ansoft HFSS-simulation program. The performances of the manufactured antenna are measured using HP vector network analyzer. Polarization patterns and return loss characteristics of the designed antenna that have been measured in anechoic chamber, are presented.     

Varying Electron Cyclotron Resonance Heating on the Levitated Dipole Experiment

Plasmas in the Levitated Dipole Experiment (LDX) are formed and sustained currently via two electron cyclotron resonance heating (ECRH) sources: 2.5 kW at 2.45 GHz and 2.5 kW at 6.4 GHz. An important topic being investigated is how varying the ECRH affects the confinement and stability of the plasma. We report the results of using different operational combinations of our RF sources, such as varying the power composition, changing the power levels, and sequencing of the onset time.     

Performance and buffering requirements of Internet protocols overATM ABR and UBR services

ATM networks are quickly being adopted as backbones over various parts of the Internet. This article studies the dynamics and performance of the TCP/IP protocol over the ABR and UBR services of ATM networks. Specifically the buffering requirements in the ATM switches as well as the ATM edge devices. It is shown that with a good switch algorithm, ABR pushes congestion to the edges of the ATM network while UBR leaves it inside the ATM portion. As a result, the switch ABR buffer requirement for zero-packet-loss high-throughput TCP transmission is a sublinear function of the number of TCP connections