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  • Conference paper
    Mougenot C, Bouchard C, Aoussat A, 2007,

    A study of designers' cognitive activity in design informational phase

    In the purpose of developping better design-support tools and improving design education, design cognition studies describe designers' mental strategies for solving design problems. So far, the first steps toward a description of designers' strategies have shown that analogies are widely used in the ideas generation phases of design process. But the very early stages of design, in the transition from brief reception to idea generation, still remain uncompletely understood and described; our study aims at exploring the way designers handle visual information beforing reaching the Eureka moment. Experiments were carried out with four professional designers from car-design European companies. The participants were invited to browse two media, printed magazines and Internet, in order to retrieve 'inspirational' images and to associate lexical descriptions to the selected images. Then in a later task, the participants had to illustrate an assigned design brief with pictures they found through online picture-search engines. The main findings deal with designers' creativity and designers' kansei: (1) In the early phases of design, the activity of browsing information sources is a combination of a generic process, shared by all designers, and individual strategies involving the designer's subjectivity. (2) New media, such as the Internet, surely impact the information phase of the early stages of design projects. Designers modify their creative strategies to adapt to the media capabilities.
  • Conference paper
    Kariniotakis G, Pinson P, Marti I, Lozano S, Giebel Get al., 2007,

    POW'WOW virtual laboratory for wind power forecasting - ViLab.

    , Pages: 963-965

    As development and operational use of forecasting solutions take more and more importance in the wind energy sector, the consortium of the European Coordination Action 'Prediction of Wakes, Waves and Offshore Wind' (Pow'Wow) has taken the initiative of setting up a Virtual Laboratory (ViLab). The related objectives are to stimulate research efforts in this field, to tighten the collaboration between forecasters and forecast users, as well as to follow and communicate the state of the art in short term prediction of wind generation. The present note clarifies the benefits for the participants to the ViLab. Also, it describes the methodology employed and some practical issues related to eg. data and confidentiality.
  • Conference paper
    Sridhar P, Nanayakkara T, Madni AM, Jamshidi Met al., 2007,

    Dynamic power management of an embedded sensor network based on actor-critic reinforcement based learning

    , Pages: 76-81

    Wireless sensor networks (WSNs) have gained tremendous popularity in recent years due to the wide range of applications envisioned - ranging from aerospace and defense to industrial and commercial. Although limited by communication and energy constraints, the low cost, small sensor nodes lend themselves to be deployed in large numbers to form a network with high spatial distribution. The overall effectiveness of the sensor network depends on how well the mutually contradicting objectives of conserving the limited on-board battery power and keeping the sensors awake for stimuli, are managed. In this paper, we have proposed an actor-critic based reinforcement learning mechanism that can be practically implemented on an embedded sensor with limited memory and processing power. Specifically, the contribution of this paper is the development of the value function (or critic/reinforcement function) that is implemented on each sensor node which aids in dynamic power scheduling based on different situations. The effectiveness of the proposed method has been demonstrated with real world experiments. © 2007 IEEE.
  • Conference paper
    Pinson P, Christensen LEA, Madsen H, Sørensen PE, Donovan MH, Jensen LEet al., 2007,

    Fluctuations of offshore wind generation - Statistical modeling

    , Pages: 151-161

    The magnitude of power fluctuations at large offshore wind farms has a significant impact on the control and management strategies of their power output. If focusing on the minute scale, one observes successive periods with smaller and larger power fluctuations. It seems that different regimes yield different behaviours of the wind power output. This paper concentrates on the statistical modelling of offshore power fluctuations, with particular emphasis on regime-switching models. More precisely, Self-Exciting Threshold AutoRegressive (SE- TAR), Smooth Transition AutoRegressive (STAR) and Markov- Switching AutoRegressive (MSAR) models are considered. The particularities of these models are presented, as well as methods for the estimation of their parameters. Simulation results are given for the case of the Horns Rev and Nysted offshore wind farms in Denmark, for time-series of power production averaged at a 1, 5, and 10-minute rate. The exercise consists in one-step ahead forecasting of these time-series with the various regime-switching models. It is shown that the MSAR model, for which the succession of regimes is represented by a hidden Markov chain, significantly outperforms the other models, for which the rules for the regime-switching are explicitly formulated.
  • Conference paper
    Nielsen HA, Pinson P, Christiansen LE, Nielsen TS, Madsen H, Badger J, Giebel G, Ravn HFet al., 2007,

    Improvement and automation of tools for short term wind power forecasting

    , Pages: 539-548

    We present the results from an on-going project financed by the Danish PSO-fund where a number of subjects relevant for further automation and improvement of short term wind power forecasts methods are studied. The technological basis of the project is adaptive forecast methods as the methods forming the basis of WPPT(Wind Power Prediction Tool) - a well proven system for wind power forecasting. In the project we investigate (i) initialization of the self-calibrating models, (ii) automatic selection of tuning parameters, (iii) robust estimation, and (iv) combination of several meteorological forecasts. In the paper we present why these aspects are considered important for further development of forecast systems. Following this we present the investigations performed and outline the solutions which follow from these investigations.
  • Conference paper
    Giebel G, Badger J, Landberg L, Nielsen HA, Nielsen TS, Madsen H, Pinson P, Sattler K, Feddersen H, Vedel Het al., 2007,

    Ensemble predictions: Understanding uncertainties

    , Pages: 838-849

    Short-term Prediction of wind power is used operationally by utilities with high wind power penetration for scheduling, trading or maintenance planning. The uncertainty of the forecast so far was produced from an analysis of historical errors as a situation-independent average value. Now, new meteorological tools are available to take the different predictability of the meteorological situation into account: Ensembles. The idea is that an ensemble of multiple forecasts, based on different initial conditions / numerical models / model runs, should give a measure of the forecast uncertainty. If the different members go on different tracks, they open up alternative scenarios for future weather. We have developed methods for (i) transforming the meteorological ensemble forecast into a wind power ensemble, and (ii) ensuring that the probabilistic properties of the derived forecasted wind power probability quantiles are correct. Also other ensemble types have been investigated. This paper summarises the findings of a Danish three year project, carried out by Ris0, DTU and DMI in conjunction with the major Danish utilities.
  • Journal article
    Long CA, Miche NDD, Childs PRN, 2007,

    Flow measurements inside a heated multiple rotating cavity with axial throughflow

    , International Journal of Heat and Fluid Flow, Vol: 28, Pages: 1391-1404

    This paper discusses experimental results from a multiple cavity test rig representative of a high pressure compressor internal air system. Measurements of the axial, tangential and radial velocity components are presented. These were made using a two component, laser doppler anemometry (LDA) system for a range of non-dimensional parameters representative of engine conditions (Re up to 4 × 106 and Rez up to 1.8 × 105). Tests were carried out for two different sizes of annular gap between the (non-rotating) drive shaft and the disc bores. The axial and radial velocities inside the cavities are virtually zero. The size of the annular gap between disc bore and shaft has a significant effect on the radial distribution of tangential velocity. For the narrow annular gap (dh/b = 0.092), there is an increase of non-dimensional tangential velocity V/Ωr with radial location from V/Ωr < 1 at the lower radii to solid body rotation V/Ωr = 1 further into the cavity. For the wider annular gap (dh/b = 0.164), there is a decrease from V/Ωr > 1 at the lower radii to solid body rotation further into the cavity. An analysis of the frequency spectrum obtained from the tangential velocity measurements is consistent with a flow structure in the r– plane consisting of pairs of contra rotating vortices.
  • Conference paper
    Long CA, Miche NDD, Childs PRN, 2007,

    Flow measurements inside a heated multiple rotating cavity with axial throughflow

    , 5th Conference on Turbulence, Heat and Mass Transfer, Publisher: ELSEVIER SCIENCE INC, Pages: 1391-1404, ISSN: 0142-727X
  • Conference paper
    Long CA, Childs PRN, 2007,

    Shroud heat transfer measurements inside a heated multiple rotating cavity with axial throughflow

    , 5th Conference on Turbulence, Heat and Mass Transfer, Publisher: ELSEVIER SCIENCE INC, Pages: 1405-1417, ISSN: 0142-727X
  • Journal article
    Long CA, Childs PRN, 2007,

    Shroud heat transfer measurements inside a heated multiple rotating cavity with axial throughflow

    , International Journal of Heat and Fluid Flow, Vol: 28, Pages: 1405-1517

    Experimental measurements of heat transfer are made from the inner peripheral surface of a rotating test rig designed to be similar to a gas turbine high pressure compressor internal air system. The test rig comprises a number of annular discs sealed at their periphery by a shroud. An axial throughflow of cooling air enters the test rig and flows through the annular section between the disc bores and a central shaft. Tests were carried out for the following range of rotational speeds and axial throughflow rates: 540 < NR < 10,800 rev/min and (corresponding to the range of rotational and axial Reynolds numbers 4 × 105 < Re < 7.7 × 106 and 3.3 × 104 < Rez < 2.2 × 105). The shroud Nusselt numbers are found to depend on the shroud Grashof number. They are relatively insensitive to changes in axial Reynolds number and two geometrically similar cavities give similar values of Nusselt number. The heat transfer from the shroud is governed by the mechanism of free convection. It is recommended that a modified form of a correlation for Rayleigh–Bénard convection in a gravitational force field be used, with appropriate modification, to predict shroud heat transfer.
  • Journal article
    Shorten R, Wirth F, Mason O, Wulff K, King Cet al., 2007,

    Stability criteria for switched and hybrid systems

    , SIAM REVIEW, Vol: 49, Pages: 545-592, ISSN: 0036-1445
  • Conference paper
    Dai Y, Li N, 2007,

    BIW concept design in virtual testing lab applying computation grid network

    , SC '07: International Conference for High Performance Computing, Networking, Storage and Analysis, Publisher: ACM, Pages: 192-197
  • Conference paper
    Yi D, Li N, 2007,

    BIW Concept Design in Virtual Testing Lab Applying Computation Grid Network

    , 3rd China HPC Workshop, Publisher: ACM, Pages: 192-197
  • Journal article
    Carroll NL, Markauskaite L, Calvo RA, 2007,

    E-portfolios for developing transferable skills in a freshman engineering course

    , IEEE TRANSACTIONS ON EDUCATION, Vol: 50, Pages: 360-366, ISSN: 0018-9359
  • Journal article
    Sorensen P, Cutululis NA, Vigueras-Rodriguez A, Madsen H, Pinson P, Jensen LE, Hjerrild J, Donovan Met al., 2007,

    Modelling of power fluctuations from large offshore wind farms

    , WIND ENERGY, Vol: 11, Pages: 29-43, ISSN: 1095-4244
  • Journal article
    Li Y-T, Leith D, Shorten RN, 2007,

    Experimental evaluation of TCP protocols for high-speed networks

    , IEEE-ACM TRANSACTIONS ON NETWORKING, Vol: 15, Pages: 1109-1122, ISSN: 1063-6692
  • Journal article
    Pinson P, Chevallier C, Kariniotakis GN, 2007,

    Trading wind generation from short-term Probabilistic forecasts of wind power

    , IEEE TRANSACTIONS ON POWER SYSTEMS, Vol: 22, Pages: 1148-1156, ISSN: 0885-8950
  • Journal article
    Shorten RN, Leith DJ, 2007,

    On queue provisioning, network efficiency and the transmission control protocol

    , IEEE-ACM TRANSACTIONS ON NETWORKING, Vol: 15, Pages: 866-877, ISSN: 1063-6692
  • Book chapter
    Porat T, Liss R, Tractinsky N, 2007,

    E-Stores Design: The Influence of E-Store Design and Product Type on Consumers’ Emotions and Attitudes

    , Lecture Notes in Computer Science (LNCS)
  • Conference paper
    Hamilton T, Morris R, Childs PRN, 2007,

    Learning from higher arts education in designing constructivist learning spaces: a case study of inQbate: the centre of excellence in teaching and learning in

    , Cambridge, 3rd ELIA Teachers' Academy, Publisher: Burlington Press, Pages: 105-108

    The aims of ‘InQbate: The Centre of Excellence in Teaching and Learning in Creativity’ aretwofold: to increase the creativity of our teaching, and to improve our teaching of creativity [Childset al, 2006]. This case study outlines how we have addressed these twin goals by drawing on theexperience of the creative disciplines in order to design physical learning spaces that supportcreation-, construction-, performance-, installation- and exhibition-based activities within a socialconstructivist pedagogical model. We hope that this will act as a bridge for increased dialogueand collaboration between Higher Arts Education and non-Arts subjects.
  • Conference paper
    Peng Z, New P, Long CA, Childs PRNet al., 2007,

    An experimental investigation of a high radius pre-swirl cooling system

    , 8th International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows, Pages: 511-518

    An experimental investigation into pre-swirl effectiveness and receiver hole discharge coefficient characteristics for a high radiusinjection pre-swirl cooling systems was carried out on an engine representative experimental rig with a 450 mm diameter rotor. Thereceiver holes and pre-swirl nozzles were located at a radius of 181 mm and 180 mm respectively. The experimental work was conductedat 5000-12000 rpm, 4 bar absolute pressure and 1.132 kg/s air supply. The maximum air supply temperature was 190ºC. Pressureand temperature distributions in the pre-swirl system were examined with an emphasis on the velocity effectiveness of thepre-swirl system as a whole and on the discharge coefficients of the rotating 'receiver holes' in the rotor. The results showed that thevelocity effectiveness increased with increasing swirl ratio resulting in reduced blade cooling flow temperature. Increasing the sealflow rate reduced the effectiveness. For the coefficient of discharge, it increased with increase in swirl ratio for most speeds. Thecoefficient of discharge also decreased with an increase in inner seal flow rate.
  • Journal article
    Kellett CM, Middleton RH, Shorten RN, 2007,

    On AIMD congestion control in multiple bottleneck networks

    , IEEE COMMUNICATIONS LETTERS, Vol: 11, Pages: 631-633, ISSN: 1089-7798
  • Journal article
    Peng Z, New P, Long CA, Childs PRNet al., 2007,

    Operating characteristics of a high radius pre-swirl cooling system

    , Hangkong Dongli Xuebao Journal of Aerospace Power, Vol: 22, Pages: 849-858, ISSN: 1000-8055

    An experimental investigation into pre-swirl effectiveness and receiver hole discharge coefficient characteristics for a high radius injection pre-swirl cooling systems was carried out on a physically representative experimental rig with a 450 mm diameter rotor. The receiver holes and pre-swirl nozzle were located at a radius of 181 mm and 180 mm respectively. The experimental work was mainly conducted at 5000-12000 r/min, 4 bar absolute pressure and 1.132 kg/s air supply. The maximum air supply temperature was 190°C. Pressure and temperature distributions in the pre-swirl system were examined with an emphasis on the velocity effectiveness of the pre-swirl system as a whole and on the discharge coefficients of the rotating 'receiver holes' in the rotor. The results showed that the velocity effectiveness increased with increasing swirl ratio resulting in reduced blade cooling flow temperature. Different seal flow configurations caused very different effectiveness at different speeds, but outflow through the inner and outer seals always gave the highest effectiveness compared other configurations. Increasing the seal flow rate reduced the effectiveness. For the coefficient of discharge, except for the low speed range, it increased with increase in swirl ratio for most speeds.
  • Journal article
    Pinson P, Nielsen HA, Moller JK, Madsen H, Kariniotakis GNet al., 2007,

    Non-parametric probabilistic forecasts of wind power: Required properties and evaluation

    , WIND ENERGY, Vol: 10, Pages: 497-516, ISSN: 1095-4244
  • Journal article
    Zhang J, Calvo R, Shephard R, Jin Cet al., 2007,

    Surveillance cattle diseases using embedded application systems

    , Wseas Transactions on Information Science and Applications, Vol: 4, Pages: 1069-1074, ISSN: 1790-0832

    Veterinary disease surveillance systems are rapidly expanding and developing. A key factor for success of a surveillance system is the ease of data capture. Real-time collection of observations of diseased cattle is difficult because observations occur in the field. This paper presents a mobile embedded application system for reporting cattle disease observations to a veterinary surveillance system in real-time. The mobile system includes an artificial intelligence system and supports data extraction via a user-friendly interface. This allows users to investigate and report cattle disease in the field and is designed to deliver benefits to producers, government surveillance systems and to the cattle industry.
  • Journal article
    Cardin MA, Wang JX, Lobaugh NJ, Guimont I, Plewes DBet al., 2007,

    A quantitative evaluation of human coordination interfaces for computer assisted surgery

    , COMPUTER AIDED SURGERY, Vol: 12, Pages: 71-81, ISSN: 1092-9088
  • Conference paper
    Boyle D, Newe T, 2007,

    A Survey of Authentication Mechanisms: Authentication for Ad-Hoc Wireless Sensor Networks

    , Sensors Applications Symposium SAS '07
  • Journal article
    Shorten RN, Kellett CM, Leith DJ, 2007,

    On the dynamics of TCP's higher moments

    , IEEE COMMUNICATIONS LETTERS, Vol: 11, Pages: 210-212, ISSN: 1089-7798
  • Conference paper
    Childs PRN, Hamilton T, Morris RD, Johnston Get al., 2007,

    Centre for technology enabled creativity

    , the 8th International Conference on Engineering and Product Design Education, Publisher: The Design Society, Pages: 367-372

    The Higher Education Funding Council for England (HEFCE), has recently awarded over £4 million (ca. 6 million Euro) to the University of Sussex and the University of Brighton to set up the Centre of Excellence in Teaching and Learning (CETL) in Creativity. The principal activities are the effective use of technology in the creative process with a particular focus, reflecting the collaboration between the two Universities involved, on engineering and design. This paper describes the pedagogic rationale behind this initiative and provides details of its implementation.
  • Conference paper
    Young JF, Picinali L, Moraitis D, 2007,

    A practice-based approach to using acoustics and technology in musicianship training

    , Pages: 61-64

    Digital audio tools can be used to facilitate many aspects of traditional note-based music making, but one of the challenges they present is also found in their potential to open up new opportunities for the shaping and deconstruction of sound in ways that are difficult to assimilate with traditional Western notation-based models of musical materials. Development of an understanding of the musical use of these new materials may require an expanded view of the nature of musicianship. This paper presents reflections on an attempt to address this by teaching musicianship via principles of acoustics and psychoacoustics in the context of a music technology undergraduate degree.

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