Date: 28 February 2008 from 10:00 to 11:00

Location: EM2.33

Name: Dr. Joan Marti, visiting professor at University of Wales

Title: "Multimodality image analysis applied to medical imaging".

Abstract:

Image segmentation and image correspondence are two key points in any image analysis system. Since most of Image Analysis applications are increasingly making use of several image modalities due to the amount of information they provide and the complementary nature of such modalities, it is necessary to modify some of the existing image segmentation algorithms or image correspondence algorithms in order to obtain effectiveness when applied to other image modalities, or even to generate optimised new algorithms for every specific modality. Examples of such developments will be provided using medical images from hospitals of the Health Area of Girona which have provided MRI images, digital mammographic (X-ray) images, and ecographic (US) images coming from breast cancer and prostate cancer screening programs.

Date: 15:00, Friday 15 February 2008

Location: EMG.20

Name: Dr Kit K Wong, University College London - Adastral Park Campus.

URL: http://www.adastral.ucl.ac.uk/~kitwong

Title: Multiuser MIMO-TDMA Systems with Statistical CSI

Abstract:

Future-generation wireless system aims to provide ubiquitous seamless connections between mobile terminals such as personal digital assistant (PDA), and computer servers so that users can enjoy high-quality high-speed multimedia services at anytime anywhere without wires. Fundamental physical challenges such as channel fading, however, have put strains on the radio resources that make reliable wireless communications difficult to achieve. In response to this, multiple-input multiple-output (MIMO) antenna systems have emerged as a promising means to provide diversity without bandwidth expansion and increase in transmit power.

Previous approaches tended to design wireless systems with maximal capacity by, for instance, an opportunistic transmission that adapts its rate according to the channel strength. Such designs are, nevertheless, of little relevance for providing real-time delay-sensitive traffic because it would be infeasible to postpone the transmission until the channel improves since the data may expire.

In this talk, it is proposed to model a delay-limited communication channel by a sequence of block transmissions and the delay constraint is novelly characterized by the probability that a target rate is not achieved for a given number of blocks. Under this setting, the cost of transmission in terms of power is minimized for attaining a given probabilistic delay constraint by exploiting the statistical channel state information (CSI) at the transmitter. Assuming a time-division downlink channel, our aim is to minimize the overall transmit power for achieving the users' outage constraint by jointly optimizing the power allocation and the time-sharing (i.e., the number of time slots) of the users.

Date: 30th January, 2008 at 1.00 pm

Location: Video Conference Room EM1.27

Name: Dr Thomas Blumensath; Research Fellow

Title: Greedier, Faster and a Little Bit Twisted: Algorithms for Sparse Signal Modelling

The acquisition, storage, transmission, processing and interpretation of signals often requires the assumption of signal structure. For example, Nyquist-Shannon sampling assumes signals to have a known bandwidth. In this talk, another powerful signal model is considered, the sparse signal model. These are quite general models that are, nevertheless, sufficiently constrained to allow novel solutions to many signal processing problems. The focus in this talk is on algorithmic aspects. Recently, we introduced the 'greedy' Gradient Pursuit framework, which allows sparse models to be used with relatively large datasets. In this talk, two extensions to this approach are considered. Firstly, because large is never large enough, we propose the use of an even greedier selection step. The second extension proposes the use of a Gradient Pursuit type algorithm to solve non-linear sparse models, which significantly widens the applicability of sparse signal modelling.

Date: 28 November 2007, 15.00

Venue: EM2.33

Name: Dr. A. Duci

University of Rostock, Germany

Presentation Title: A Banach like metrics on the space of compact sets

Presentation Abstract:

We present and study a family of metrics on the space of compact subsets of $\real^N$ (that we call ``shapes''). These metrics are ``geometric'', that is, they are independent of rotation and translation; and these metrics enjoy many interesting properties, as, for example, the existence of minimal geodesics. We view our space of shapes as a subset of Banach (or Hilbert) manifolds: so we can define a ``tangent manifold'' to shapes, and (in a very weak form) talk of a ``Riemannian Geometry'' of shapes. Some of the metrics that we propose are topologically equivalent to the Hausdorff metric; but at the same time, they are more ``regular'', since we can hope for a local uniqueness of minimal geodesics. We also study properties of the metrics obtained by isometrically identifying a generic metric space with a subset of a Banach space toobtain a rigidity result.their state vectors in data with false alarms and missed detections. These techniques have a wide range range of applications within electrical engineering and can be deployed on many different types of sensors.Target tracking algorithms are an essential building block of systems that perform functions such as surveillance, guidance or obstacle avoidance. Tracking algorithms take their input measurements from sensors which provide the signals such as radar, sonar or video. The measurements are taken at regular intervals and the task is to estimate the state of a target at each point in time, such as its position, velocity or other attribute. Successive estimates provide the tracks which describe the trajectory of a target. Whilst these techniques are attracting international attention within the engineering academia and in industry, they is relatively unknown within the mathematics and statistics community.

Dr Sumeetpal Singh is a Lecturer in the Engineering and Statistics departments at the University of Cambridge whose interests include developing methodologies for stochastic filtering using point processes and sequential Monte Carlo techniques.

Date: 21 November 2007, 14.00

Venue: EM2.33

Name: Dr S Singh

Signal Processing Lab, Cambridge University Engineering Department

Presentation Title:

Multiple Target Filtering with Point Processes

Presentation Abstract:

The Point Processes framework is both natural and rigorous for the multiple-object tracking problem and is increasingly playing a central role in the derivation of new target tracking algorithms. Interest in this framework is largely due to the derivation of a filter that propagates the first moment of Spatial Point Processes observed in noise by Ronald Mahler. Since then there have been several extensions to this result with accompanying numerical implementations based on Sequential Monte Carlo. This talk aims to provide an overview of this new area, its applications and current research initiatives.

Background

The point-process approach for multi-object stochastic filtering was motivated by the need to develop mathematically rigorous yet practical techniques for tracking multiple targets from sensor data. These filters have led to robust multiple-target tracking algorithms for estimating both the correct number of targets and their state vectors in data with false alarms and missed detections. These techniques have a wide range range of applications within electrical engineering and can be deployed on many different types of sensors.

Target tracking algorithms are an essential building block of systems that perform functions such as surveillance, guidance or obstacle avoidance. Tracking algorithms take their input measurements from sensors which provide the signals such as radar, sonar or video. The measurements are taken at regular intervals and the task is to estimate the state of a target at each point in time, such as its position, velocity or other attribute. Successive estimates provide the tracks which describe the trajectory of a target.

Whilst these techniques are attracting international attention within the engineering academia and in industry, they is relatively unknown within the mathematics and statistics community.

Dr Sumeetpal Singh is a Lecturer in the Engineering and Statistics departments at the University of Cambridge whose interests include developing methodologies for stochastic filtering using point processes and sequential Monte Carlo techniques.

Date: 15 November 2007, 14.15

Venue: EM2.33

Name: Dr. Savvas Kosmopoulos

Space Engineering, Italy

Presentation Title:

Microwave filters for space application

Presentation Abstract: Microwave/millimete-wave (mmWaves) filters belong to most common passive components in any microwave/mmWaves network. The number of research contributions devoted to microwave/mmWaves filters is enormous, and even a general overview of all important aspects in filter design and realization is beyond the scope of this presentation. Indeed, we will focus our attention on the use of CAD methods for the designing of selected microwave/mmWaves filters which are typically used on space communications applications (e.g., waveguide technology, cavity technology, interdigital and combline technology, E-Plane technology). Research on microwave filters spans over more than fifty years. The literature related to that topic is very rich, and therefore it is not possible to describe all important steps of this development in a few hours presentation. Therefore, only some but most important milestones in the development of theory and design approaches for microwave/mmwaves filters will be outlined. Subsequently, the projection and designing procedures, accompanied by bred-boarding measurement results, for various space-qualified filters will be presented (e.g., Interdigital and Combline Band-Pass Filters for the Meteosat Second Generation Satellite, a UHF duplexes for the METOP Satellite; a Ku-Band Waveguide-based Band- Pass Filter for VSAT applications; a S-Band Diplexer for multi-beam space qualified Antennas).

Date: Tuesday 13 November 2007, 13:55

Venue: EM3.02

Name: Dr. Ioannis Ivrissimtzis

Durham University

Presentation Title:

Point Set Denoising using Variational Bayesian Methods

Presentation Abstract: In statistical modeling, the model parameters are usually estimated by maximizing a probability measure, such as the likelihood or the posterior. In contrast, variational Bayesian methods treat the parameters of a model as probability distributions and compute optimal distributions for them. We applied a variational Bayesian technique to surface fitting for height field data. A series of uniform bicubic B-spline surfaces with increasing numbers of control points are fitted on a local neighborhood of the data, and the model with the highest evidence, is selected. As an application, the basic surface fitting algorithm is used for point denoising.

Date: Tuesday 13 November 2007, 13:15

Venue: EM3.02

Name: Prof. Seungyong Lee

Postch University, Korea

Presentation Title:

Abstract Line Drawings from 2D Images

Presentation Abstract: We present a novel scheme for automatically generating line drawings from 2D images, aiming to facilitate effective visual communication. In contrast to conventional edge detectors, our technique imitates the human line drawing process and consists of two parts: line extraction and line rendering. We propose a novel line extraction method based on likelihood-function estimation, which effectively finds the genuine shape boundaries. We consider the feature scale and the blurriness of lines with which the detail and the focus-level of lines are controlled in the rendering. We also employ stroke textures to provide a variety of illustration styles. Experimental results demonstrate that our technique generates various kinds of line drawings from 2D images enabled by the control over detail, focus, and style.

Date: Wednesday 24 October 2007, 14.15

Venue: EM2.33

Name: Prof. Janusz Bialek's

University of Edinburgh

Presentation Title:

Why has it happened again? The UCTE power supply disturbance in 2006

Presentation Abstract: The presentation will start with an overview of the UCTE blackout of 2006 with the special attention to the role of wind generation. Next a comparison will be made with the blackouts in the US and Italy of 2003. The main conclusion of the paper is that the European utilities have not really learned the lessons from the blackouts of 2003. Increased liberalisation of electricity supply industry has resulted in a significant increase in inter-area (or crossborder) trades which often are not properly accounted for when assessing system security. This is compounded by the uncertainty due to wind generation. The traditional decentralised way of operating systems by TSOs, with each TSO looking after its own control area and little information exchange, resulted in inadequate and slow response to contingencies. A new mode of coordinated operation for real-time security assessment and control is needed in order to maintain system security. This new mode of operation requires overcoming a number of organisational, psychological, legal and technical challenges but the alternative is either to risk another blackout or run the interconnected system very conservatively, maintaining large security margin at a high cost to the consumer.

Date: Wednesday 6 June 2007, 10:00

Venue: EM 2.33

Name: Prof. Adrian Bowyer,

University of Bath

Presentation Title: Next generation CDMA technology

Presentation Abstract: Look at your computer setup. Imagine if you hooked up a 3D printer.

Instead of printing on bits of paper this 3D printer makes real, robust, mechanical parts. To give you an idea of how robust these parts are think of Lego bricks and you're in the right area. You could make lots of useful stuff, but interestingly you could also make most of the parts to make another 3D printer. That would be a machine that could copy itself.

This talk will be abut RepRap - the Replicating Rapid-prototyper. This 3D printer will make components using fused-deposition Rapid Prototyping, which builds the component up in layers of plastic. This technology already exists, but the cheapest commercial machine would set you back £15,000. And it isn't even designed so that it can make itself.

So what the RepRap team are doing is to develop and to give away the designs for a much cheaper machine with the novel capability of being able to self-copy (material costs will be about £300). We are distributing the RepRap machine entirely free to everyone using open-source - so, if you have one, you can make another and give it to a friend...

Date: 3 October 2007, 14.15

Venue: EM2.33

Name: Dr. Chaoran Du

University of Edinburgh

Presentation Title:

Application of Precoding Schemes in MIMO Sonar

Presentation Abstract: Motivated by the dramatic advances offered by multiple-input multiple-output (MIMO) systems in communications, we intend to extend this concept of transmitter precoding schemes in realistic MIMO sonar systems. Unlike phased arrays whose antennas are closely located in order to provide coherent processing gain, the MIMO system uses large sensor spacings to exploit the spatial diversity gain, which can overcome the deep fading problem by taking advantage of multipaths effects. The work done so far is setting up a simple MIMO system model which can be applied to both radar and sonar scenarios.

Date: Thursday 28 June 2007, 11:00

Venue: EM 2.33

Name: Prof. Hsiao-Hua Chen,

Institute of Communications Engineering, National Sun Yat-Sen University, Taiwan.

Presentation Title: Next generation CDMA technology

Presentation Abstract: This talk will review our ongoing research activities on time-frequency
two-dimensional CDMA coding. In particular, we will propose a new CDMA code
design methodology, namely Real Environment Adapted Linearization (REAL)
approach, which can generate CDMA code sets with inherent immunity against
multipath interference and multiple access interference for both up-link and
down-link transmissions. It will also be shown that an interference-free
CDMA can only be implemented using orthogonal complementary codes (OCCs).
Several other issues on the OCC-CDMA, such as its system implementation and
performance, will also be addressed.

Hsiao-Hwa Chen (hshwchen@ieee.org) is currently a full-Professor, National Sun Yat-Sen University, Taiwan. He has been a visiting Professor to Department of Electrical Engineering, University of Kaiserslautern, Germany, in 1999, the Institute of Applied Physics, Tsukuba University, Japan, in 2000, Institute of Experimental Mathematics, University of Essen, Germany in 2002 (under DFG Fellowship), Department of Information Engineering, The Chinese University of Hong Kong, 2003, and Department of Electronics Engineering, The City University of Hong Kong, 2006.

His current research interests include wireless networking, MIMO systems, and next generation CDMA technologies for future wireless communications. He has authored or coauthored over 160 technical papers in major international journals and conferences, and three books and two book chapters in the areas of communications. He served or is serving as a TPC member, International Steering Committee member and Symposium Chair of more than 50 major international conferences, including IEEE VTC 2003 Fall, IEEE ICC 2004, IEEE Globecom 2004, IEEE ICC 2005, IEEE Globecom 2005, IEEE ICC 2006, IEEE Globecom 2006, IEEE VTC 2006 Spring, IEEE ICC 2007, etc. He served or is serving as the Editor, member of Editorial Board and Guest Editor of many international journals, including IEEE Communications Magazine, IEEE JSAC, IEEE Vehicular Technology Magazine, IEEE Wireless Communications Magazine, IEEE Trans. On Wireless Communications, Wireless Communications and Mobile Computing (WCMC) Journal, International Journal of Communication Systems, International Journal of Security and Networks, etc. He has been a Guest Professor of Zhejiang University, China, and Shanghai Jiao Tung University, China, since 2003 and 2005 respectively.

Date: Thursday 21 June 2007, 15:00

Venue: EM3.02

Name: Prof. Heung-Gyoon Ryu

Department of Electrical, Electronic and Computer Engineering, Chungbuk National University, Republic of Korea.

Presentation Title:

Adaptive Frequency Diversity OFDM Communication System in the Narrow-Band Interference Channel

Presentation Abstract: In this study, we consider the FD-OFDM (frequency diversity orthogonal frequency division multiplexing) system in the narrow-band jamming interference channel. Then, we propose an adaptive FD-OFDM to cope with the interference more adaptively. In FD-OFDM system, the information symbol of each parallel branch is multiplied by the orthogonal sequence and distributed into all sub-carriers. So, each sub-carrier transmits the orthogonally segmented information from the parallel branches in the FD-OFDM symbol duration. This FD-OFDM shows the frequency diversity characteristic. Therefore, FD-OFDM can be robust to the narrow-band jamming interference. But, the FD-OFDM also can’t suppress its performance loss in a very strong narrow-band jamming interference channel. So, in this study, adaptive FD-OFDM system is proposed to countermeasure the deficiency of the FD-OFDM system, and it is very robust to the high power narrow-band jamming interference. In this adaptive FD-OFDM, the overall system bandwidth is divided into several sub-bandwidths. Modulation level of each sub-bandwidth is adaptively controlled according to the channel environment. Therefore, it can get the high transmission throughput even in the severe channel condition. Simulation results show that this adaptive FD-OFDM is better than the FD-OFDM in the stronger narrow-band jamming interference.

Biography: Heung-Gyoon Ryu received the B.S., M.S., and Ph.D. degrees in electronic engineering from Seoul National University in 1982, 1984, and 1989, respectively. Since 1988, he has been with Chungbuk National University, Korea, where he is currently a Full Professor. He worked as Chief of RICIC (research institute of computer, information communication center) in Chungbuk National University from March 2002 to Feb 2004. His main research interests are digital communication systems, communication circuit design, spread spectrum system and communication signal processing. He has published more than 200 papers in journals and conferences. He was a winner of ‘2002 ACADEMY AWARD’ from the Korea Electromagnetic Engineering Society, Korea.