Recent Submissions

  • Modeling emergent patterns of dynamic desert ecosystems

    Stewart, J.; Parsons, A. J.; Wainwright, J.; Okin, G. S.; Bestelmeyer, B. T.; Fredrickson, E. L.; Schlesinger, W. H.; University of Sheffield (Ecological Society of America, 2014-08-01)
    In many desert ecosystems, vegetation is both patchy and dynamic: vegetated areas are interspersed with patches of bare ground, and both the positioning and the species composition of the vegetated areas exhibit change through time. These characteristics lead to the emergence of multi-scale patterns in vegetation that arise from complex relationships between plants, soils, and transport processes. Previous attempts to probe the causes of spatial complexity and predict responses of desert ecosystems tend to be limited in their focus: models of dynamics have been developed with no consideration of the inherent patchiness in the vegetation, or else models have been developed to generate patterns with no consideration of the dynamics. Here we develop a general modelling framework for the analysis of ecosystem change in deserts that is rooted in the concept of connectivity and is derived from a detailed process-based understanding. We explicitly consider spatial interactions among multiple vegetation types and multiple resources, and our model is formulated to predict responses to a variety of endogenous and exogenous disturbances. The model is implemented in the deserts of the American Southwest both to test hypotheses of the causes of the invasion of woody shrubs, and to test its ability to reproduce observed spatial differences in response to drought in the 20th century. The model’s performance leads us to argue that vertical and lateral connectivity are key emergent properties of the ecosystem, which both control its behavior and provide indicators of its state. If this argument is shown to be compatible with field observations, the model presented here will provide a more certain approach toward preventing further degradation of semiarid grasslands.
  • Cascaded multimodal biometric recognition framework

    Albesher, Badr; Kurugollu, Fatih; Bouridane, Ahmed; Baig, Asim; Queen's University, Belfast (IET, 2013-08-15)
    A practically viable multi-biometric recognition system should not only be stable, robust and accurate but should also adhere to real-time processing speed and memory constraints. This study proposes a cascaded classifier-based framework for use in biometric recognition systems. The proposed framework utilises a set of weak classifiers to reduce the enrolled users’ dataset to a small list of candidate users. This list is then used by a strong classifier set as the final stage of the cascade to formulate the decision. At each stage, the candidate list is generated by a Mahalanobis distance-based match score quality measure. One of the key features of the authors framework is that each classifier in the ensemble can be designed to use a different modality thus providing the advantages of a truly multimodal biometric recognition system. In addition, it is one of the first truly multimodal cascaded classifier-based approaches for biometric recognition. The performance of the proposed system is evaluated both for single and multimodalities to demonstrate the effectiveness of the approach.
  • Privacy region protection for H.264/AVC with enhanced scrambling effect and a low bitrate overhead

    Wang, Yongsheng; O׳Neill, Máire; Kurugollu, Fatih; O׳Sullivan, Elizabeth; Queen's University, Belfast (Elsevier, 2015-05-12)
    While video surveillance systems have become ubiquitous in our daily lives, they have introduced concerns over privacy invasion. Recent research to address these privacy issues includes a focus on privacy region protection, whereby existing video scrambling techniques are applied to specific regions of interest (ROI) in a video while the background is left unchanged. Most previous work in this area has only focussed on encrypting the sign bits of nonzero coefficients in the privacy region, which produces a relatively weak scrambling effect. In this paper, to enhance the scrambling effect for privacy protection, it is proposed to encrypt the intra prediction modes (IPM) in addition to the sign bits of nonzero coefficients (SNC) within the privacy region. A major issue with utilising encryption of IPM is that drift error is introduced outside the region of interest. Therefore, a re-encoding method, which is integrated with the encryption of IPM, is also proposed to remove drift error. Compared with a previous technique that uses encryption of IPM, the proposed re-encoding method offers savings in the bitrate overhead while completely removing the drift error. Experimental results and analysis based on H.264/AVC were carried out to verify the effectiveness of the proposed methods. In addition, a spiral binary mask mechanism is proposed that can reduce the bitrate overhead incurred by flagging the position of the privacy region. A definition of the syntax structure for the spiral binary mask is given. As a result of the proposed techniques, the privacy regions in a video sequence can be effectively protected by the enhanced scrambling effect with no drift error and a lower bitrate overhead.
  • Theoretical investigation into balancing high-speed flexible shafts, by the use of a novel compensating balancing sleeve

    Knowles, Grahame; Kirk, Antony; Stewart, Jill; Bickerton, Ron; Bingham, Chris; University of Lincoln (IMechE, 2013-12-31)
    Traditional techniques for balancing long, flexible, high-speed rotating shafts are inadequate over a full range of shaft speeds. This problem is compounded by limitations within the manufacturing process, which have resulted in increasing problems with lateral vibrations and hence increased the failure rates of bearings in practical applications. There is a need to develop a novel strategy for balancing these coupling shafts that is low cost, robust under typically long-term operating conditions and amenable to on-site remediation. This paper proposes a new method of balancing long, flexible couplings by means of a pair of balancing sleeve arms that are integrally attached to each end of the coupling shaft. Balance corrections are applied to the free ends of the arms in order to apply a corrective centrifugal force to the coupling shaft in order to limit shaft-end reaction forces and to impart a corrective bending moment to the drive shaft that limits shaft deflection. The aim of this paper is to demonstrate the potential of this method, via the mathematical analysis of a plain, simply supported tube with uniform eccentricity and to show that any drive shaft, even with irregular geometry and/or imbalance, can be converted to an equivalent encastre case. This allows for the theoretical possibility of eliminating the first simply supported critical speed, thereby reducing the need for very large lateral critical speed margins, as this requirement constrains design flexibility. Although the analysis is performed on a sub 15 MW gas turbine, it is anticipated that this mechanism would be beneficial on any shaft system with high-flexibility/shaft deflection.
  • Blind image watermark detection algorithm based on discrete shearlet transform using statistical decision theory

    Ahmaderaghi, Baharak; Kurugollu, Fatih; Rincon, Jesus Martinez Del; Bouridane, Ahmed; Queen's University, Belfast (IEEE, 2018-01-15)
    Blind watermarking targets the challenging recovery of the watermark when the host is not available during the detection stage.This paper proposes Discrete Shearlet Transform (DST) as a new embedding domain for blind image watermarking. Our novel DST blind watermark detection system uses a non-additive scheme based on the statistical decision theory. It first computes the Probability Density Function (PDF) of the DST coefficients modelled as a Laplacian distribution. The resulting likelihood ratio is compared with a decision threshold calculated using Neyman-Pearson criterion to minimise the missed detection subject to a fixed false alarm probability. Our method is evaluated in terms of imperceptibility, robustness and payload against different attacks (Gaussian noise, Blurring, Cropping, Compression and Rotation) using 30 standard grayscale images covering different characteristics (smooth, more complex with a lot of edges and high detail textured regions). The proposed method shows greater windowing flexibility with more sensitive to directional and anisotropic features when compared against Discrete Wavelet and Contourlets.
  • Kinetic modelling of synaptic functions in the alpha rhythm neural mass model

    Basabdatta, Sen Bhattacharya; Coyle, Damien H; Maguire, Liam P; Stewart, Jill; University of Lincoln (Springer-Verlag Berlin Heidelberg, 2012)
    In this work, we introduce the kinetic framework for modelling synaptic transmission in an existing neural mass model of the thalamocortical circuitry to study Electroencephalogram (EEG) slowing within the alpha frequency band (8–13 Hz), a hallmark of Alzheimer’s disease (AD). Ligand-gated excitatory and inhibitory synapses mediated by AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) and GABAA (gamma-amino-butyric acid) receptors respectively are modelled. Our results show that the concentration of the GABA neurotransmitter acts as a bifurcation parameter, causing the model to switch from a limit cycle mode to a steady state. Further, the retino-geniculate pathway connectivity plays a significant role in modulating the power within the alpha band, thus conforming to research proposing ocular biomarkers in AD. Overall, kinetic modelling of synaptic transmission in neural mass models has enabled a more detailed investigation into the neural correlates underlying abnormal EEG in AD.
  • Validation of electrokinetic stabilisation of M5 Junction 7

    Alder, David; Lamont-Black, J; Hamza, Omar; Jackson, C; Jones, C; University of Derby; Electrokinetic; Jacobs; Newcastle University (ICE, 2019-01-07)
    Electrokinetic method has been increasingly applied to repair infrastructure earthwork involving landslip. The work presented in this paper attempts to improve the current understanding of this innovative technique by verifying the effectiveness of Electrokinetic treatment using in-situ and laboratory testing in addition to monitoring data obtained from the first full scale project implementing this technique, which has been carried out recently for a defected embankment slope on M5- Junction 7 in the UK. The paper outlines the design and implementation aspects of the project and discusses the findings of the post construction verification.
  • Optimizing wide-area sound reproduction using a single subwoofer with dynamic signal decorrelation

    Hill, Adam J.; Moore, J.B.; University of Derby (Audio Engineering Society, 2019-03-10)
    A central goal in small room sound reproduction is achieving consistent sound energy distribution across a wide listening area. This is especially difficult at low-frequencies where room-modes result in highly position-dependent listening experiences. While numerous techniques for multiple-degree-of-freedom systems exist and have proven to be highly effective, this work focuses on achieving position-independent low-frequency listening experiences with a single subwoofer. The negative effects due to room-modes and comb-filtering are mitigated by applying a time-varying decorrelation method known as dynamic diffuse signal processing. Results indicate that spatial variance in magnitude response can be significantly reduced, although there is a sharp trade-off between the algorithm’s effectiveness and the resulting perceptual coloration of the audio signal.
  • Frontal view gait recognition with fusion of depth features from a time of flight camera

    Afendi Tengku Mohd; Kurugollu, Fatih; Crookes, Danny; Bouridane, Ahmed; Farid, Mohsen; Queen's University, Belfast; University of Derby; Northumbria University (IEEE, 2018-09-17)
    Frontal view gait recognition for people identification has been carried out using single RGB, stereo RGB, Kinect 1.0 and Doppler radar. However, existing methods based on these camera technologies suffer from several problems. Therefore, we propose a four-part method for frontal view gait recognition based on fusion of multiple features acquired from a Time of Flight (ToF) camera. We have developed a gait data set captured by a ToF camera. The data set includes two sessions recorded seven months apart, with 46 and 33 subjects respectively, each with six walks with five covariates. The four-part method includes: a new human silhouette extraction algorithm that reduces the multiple reflection problem experienced by ToF cameras; a frame selection method based on a new gait cycle detection algorithm; four new gait image representations; and a novel fusion classifier. Rigorous experiments are carried out to compare the proposed method with state-of-the-art methods. The results show distinct improvements over recognition rates for all covariates. The proposed method outperforms all major existing approaches for all covariates and results in 66.1% and 81.0% Rank 1 and Rank 5 recognition rates respectively in overall covariates, compared with a best state-of-the-art method performance of 35.7% and 57.7%.
  • Educational advantage and employability of UK university graduates

    Pigden, Louise; Moore, Garford; University of Derby (Emerald, 2019-02-20)
    In the UK, the majority of university students specialise and study just one subject at bachelor degree level, commonly known in the UK as a single honours degree. However, nearly all British universities will permit students if they wish to study two or even three subjects, so-called joint or combined honours degrees, internationally known as a double major. The purpose of this paper is to explore whether educational advantage, measured by the “Participation of Local Areas” (POLAR) classification, correlated with rates of graduate destinations for joint and single honours graduates. This study focused particularly on Russell Group and Post-92 Universities. The authors analysed the complete data set provided from the Higher Education Statistics Agency Destination of Leavers from the Higher Education survey, and combined this with data from the POLAR4 quintiles, which aggregate geographical regions across the UK based on the proportion of its young people that participate in higher education. The data were analysed to establish whether there was a difference in the highly skilled graduate employability of the joint honours students, focusing particularly on Russell Group and Post-92 Universities, in order to build on previous published work. Single honours and joint honours graduates from higher participation POLAR4 quintiles were more likely to be in a highly skilled destination. However at both the Russell Group and the Post-92 universities, respectively, there was no trend towards a smaller highly skilled destinations gap between the honours types for the higher quintiles. For the highest POLAR4 quintile, the proportion of joint honours graduates was substantially higher at the Russell Group than at Post-92 universities. Furthermore, in any quintile, there were proportionately more joint honours graduates from the Russell Group, compared with single honours graduates, and increasingly so the higher the quintile. This study focused on joint honours degrees in the UK where the two or three principal subjects fall into different Joint Academic Coding System (JACS) subject areas, i.e. the two or three subjects are necessarily diverse rather than academically cognate. This excluded the class of joint honours degrees where the principal subjects lie within the same JACS subject area, i.e. they may be closer academically, although still taught by different academic teams. However, the overall proportion of joint honours graduates identified using the classification was in line with the UCAS (2017) data on national rates of combined studies acceptances. All Russell Group graduates, irrespective of their POLAR4 quintile, were far more likely to be in a highly skilled destination than single or joint honours graduates of Post-92 universities. Even the lowest quintile graduates of the Russell Group had greater rates of highly skilled destination than the highest quintile from Post-92 universities, for both single and joint honours graduates. This demonstrated the positive impact that graduating from the Russell Group confers on both single and joint honours graduates. This study could not explain the much smaller gap in the highly skilled destinations between single honours and joint honours graduates found in the Russell Group, compared with the Post-92. Why do a higher proportion of joint honours graduates hail form the upper POLAR4 quintiles, the Russell Group joint honours graduates were more disproportionately from the upper POLAR4 quintiles and the joint honours upper POLAR4 quintiles represented such a larger proportion of the Russell Group overall undergraduate population? Other student characteristics such as tariff on entry, subjects studied, gender, age and ethnicity might all contribute to this finding. This study demonstrated that, averaged across all universities in the UK, there was a trend for both single honours and joint honours graduates from higher participation POLAR4 quintiles to be more likely to be in a highly skilled destination, i.e. the more educationally advantaged, were more likely to be in a highly skilled destination, as a proportion of the total from each honours type. This accorded with HESA (2018b) data, but expanded those findings to include direct consideration of joint honours graduates.
  • A shape grammar approach to climatically adaptable facade systems with real time performance evaluation.

    TUNG NGUYEN, BORIS CERANIC, CHRISTOPHER CALLAGHAN; University of Derby (WIT Press, 2019-01-01)
    New computational techniques have been introduced to assist the design of adaptable building facades and to help quantify relationships between the building envelope and the environment. Designers increasingly use generative design approach for form-generation of building envelopes, and the organisation of components over a predefined form. In this research an original shape grammar approach for façade systems generation is proposed, with a rule-based method for the creation and exploration of complex shape composites based upon a set of simple initial shapes and predefined rules of composition. This is in order to explore a form finding of set of different building façade configurations before merging generated data into a simulated process of real-time daylighting and heat gains performance evaluation. The developed models adapt via responding to the data-regulation protocols responsible for sensing and processing building performance data in real time. The research reports on the prototype system development and testing, allowing continuous evaluation of multiple solutions and presenting opportunity for further improvement via multi-objective optimisation, which would be very difficult to do, if not impossible, with conventional design methods
  • Assessing Domain Specificity in the Measurement of Mathematics Calculation Anxiety

    Hunt, Thomas E.; Bagdasar, Ovidiu; Sheffield, David; Schofield, Malcolm B.; University of Derby (Hindawi, 2019-02-03)
    An online, cross-sectional approach was taken, including an opportunity sample of 160 undergraduate students from a university in the Midlands, UK. Exploratory factor analysis indicated a parsimonious, four-factor solution: abstract maths anxiety, statistics probability anxiety, statistics calculation anxiety, and numerical calculation anxiety. The results support previous evidence for the existence of a separate “numerical anxiety” or “arithmetic computation” anxiety component of maths anxiety and also support the existence of anxiety that is specific to more abstract maths. This is the first study to consider the multidimensionality of maths anxiety at the level of the calculation type. The 26-item Maths Calculation Anxiety Scale appears to be a useful measurement tool in the context of maths calculation specifically.
  • On some results concerning the polygonal polynomials.

    Andrica, Dorin; Bagdasar, Ovidiu; Babeș-Bolyai University; University of Derby (Technical University of Cluj-Napoca., 2019-02-13)
    In this paper we define the $n$th polygonal polynomial $P_n(z) = (z-1)(z^2-1)\cdots(z^n-1)$ and we investigate recurrence relations and exact integral formulae for the coefficients of $P_n(z)$ and for those of the Mahonian polynomials $Q_n(z)=(z+1)(z^2+z+1)\cdots(z^{n-1}+\cdots+z+1)$. We also explore numerical properties of these coefficients, unraveling new meanings for old sequences and generating novel entries to the Online Encyclopedia of Integer Sequences (OEIS). Some open questions are also formulated.
  • Innovative approach to sustainable material sourcing and its impact on building performance

    Rajpurohit J.S., Ceranic B., Latham D.; University of Derby (WIT Press, 2019-01-29)
    In this paper, a novel use of building materials and their impact on the building performance and its climatic adaptability is explored, based on a complex case study of a unique low energy sustainable building project. In particular, an innovative use of sycamore and its suitability as a structural and constructional timber has been investigated and reported, given that the current codes of practice deem that is not appropriate for structural applications due to its durability. A research method of in-situ longitudinal study has been adopted, concentrating on the monitoring and assessment of its structural performance and conditions in which it might deteriorate. On the component level, the research reports on the methods and standards of sycamore grading and classification, service classes, resistance to decay, impact of the moisture movement and results of its laboratory and in situ testing. On the system level, the climatic adaptability of the building as a whole has been analysed via dynamic performance simulation and compared to the in-situ measurements. This was important in order to develop a holistic building performance monitoring strategy, but in particular, to understand the impact of building microclimate on the sycamore frame and hempcrete components of the external load-bearing wall. So far research has concluded that sycamore can be used as structural and constructional material in building design, but due attention has to be paid to construction detailing and provision of a breathable, low humidity environment with an effective resistance to decay and insect attack. This includes measures that ensure a low equilibrium moisture content conditions, effective ventilation provision and appropriate service class uses. It is important to state however, given the single site locality of sycamore sourcing, that results can only be interpreted in the context of the given case study, i.e. they cannot be extrapolated to broader geographical extents.
  • Multi-objective evolutionary—fuzzy augmented flight control for an F16 aircraft

    Stewart, P; Gladwin, D; Parr, M; Stewart, J; University of Sheffield (2009-11-05)
    In this article, the multi-objective design of a fuzzy logic augmented flight controller for a high performance fighter jet (the Lockheed-Martin F16) is described. A fuzzy logic controller is designed and its membership functions tuned by genetic algorithms in order to design a roll, pitch, and yaw flight controller with enhanced manoeuverability which still retains safety critical operation when combined with a standard inner-loop stabilizing controller. The controller is assessed in terms of pilot effort and thus reduction of pilot fatigue. The controller is incorporated into a six degree of freedom motion base real-time flight simulator, and flight tested by a qualified pilot instructor.
  • Behavioural Digital Forensics Model: Embedding Behavioural Evidence Analysis into the Investigation of Digital Crimes

    Al Mutawa, Noora; Bryce, Joanne; Franqueira, Virginia N. L.; Marrington, Andrew; Read, Janet C.; University of Derby (Elsevier, 2019-03)
    The state-of-the-art and practice show an increased recognition, but limited adoption, of Behavioural Evidence Analysis (BEA) within the Digital Forensics (DF) investigation process. Yet, there is currently no BEA-driven process model and guidelines for DF investigators to follow in order to take advantage of such an approach. This paper proposes the Behavioural Digital Forensics Model to fill this gap. It takes a multidisciplinary approach which incorporates BEA into in-lab investigation of seized devices related to interpersonal cases (i.e., digital crimes involving human interactions between offender(s) and victim(s)). The model was designed based on the application of traditional BEA phases to 35 real cases, and evaluated using 5 real digital crime cases - all from Dubai Police archive. This paper, however, provides details of only one case from this evaluation pool. Compared to the outcome of these cases using a traditional DF investigation process, the new model showed a number of benefits. It allowed a more effective focusing of the investigation, and provided logical directions for identifying the location of further relevant evidence. It also enabled a better understanding and interpretation of victim/offender behaviours (e.g., probable offenders' motivations and modus operandi), which facilitated a more in depth understanding of the dynamics of the specific crime. Finally, in some cases, it enabled the identification of suspect's collaborators, something which was not identified via the traditional investigative process.
  • Comparison of two novel MRAS based strategies for identifying parameters in permanent magnet synchronous motors.

    Liu, Kan; Zhang, Qiao; Zhu, Zi-Qiang; Zhang, Jing; Shen, An-Wen; Stewart, Paul; University of Lincoln UK (Springer., 2010-11-11)
    Two Model Reference Adaptive System (MRAS) estimators are developed for identifying the parameters of permanent magnet synchronous motors (PMSM) based on Lyapunov stability theorem and Popov stability criterion, respectively. The proposed estimators only need online detection of currents, voltages and rotor rotation speed, and are effective in the estimation of stator resistance, inductance and rotor flux-linkage simultaneously. Their performances are compared and verified through simulations and experiments. It shows that the two estimators are simple and have good robustness against parameter variation and are accurate in parameter tracking. However, the estimator based on Popov stability criterion, which can overcome the parameter variation in a practical system, is superior in terms of response speed and convergence speed since there are both proportional and integral units in the estimator in contrast to only one integral unit in the estimator based on Lyapunov stability theorem. In addition, there is no need of the expert experience which is required in designing a Lyapunov function
  • Improved decision support for engine-in-the-loop experimental design optimization.

    Gladwin, D; Stewart, P; Stewart, J; Chen, R; Winward, E; University of Sheffield; University of Lincoln.; Loughborough university (Sage., 2009-09-25)
    Experimental optimization with hardware in the loop is a common procedure in engineering and has been the subject of intense development, particularly when it is applied to relatively complex combinatorial systems that are not completely understood, or where accurate modelling is not possible owing to the dimensions of the search space. A common source of difficulty arises because of the level of noise associated with experimental measurements, a combination of limited instrument precision, and extraneous factors. When a series of experiments is conducted to search for a combination of input parameters that results in a minimum or maximum response, under the imposition of noise, the underlying shape of the function being optimized can become very difficult to discern or even lost. A common methodology to support experimental search for optimal or suboptimal values is to use one of the many gradient descent methods. However, even sophisticated and proven methodologies, such as simulated annealing, can be significantly challenged in the presence of noise, since approximating the gradient at any point becomes highly unreliable. Often, experiments are accepted as a result of random noise which should be rejected, and vice versa. This is also true for other sampling techniques, including tabu and evolutionary algorithms. After the general introduction, this paper is divided into two main sections (sections 2 and 3), which are followed by the conclusion. Section 2 introduces a decision support methodology based upon response surfaces, which supplements experimental management based on a variable neighbourhood search and is shown to be highly effective in directing experiments in the presence of a significant signal-to-noise ratio and complex combinatorial functions. The methodology is developed on a three-dimensional surface with multiple local minima, a large basin of attraction, and a high signal-to-noise ratio. In section 2, the methodology is applied to an automotive combinatorial search in the laboratory, on a real-time engine-in-the-loop application. In this application, it is desired to find the maximum power output of an experimental single-cylinder spark ignition engine operating under a quasi-constant-volume operating regime. Under this regime, the piston is slowed at top dead centre to achieve combustion in close to constant volume conditions. As part of the further development of the engine to incorporate a linear generator to investigate free-piston operation, it is necessary to perform a series of experiments with combinatorial parameters. The objective is to identify the maximum power point in the least number of experiments in order to minimize costs. This test programme provides peak power data in order to achieve optimal electrical machine design. The decision support methodology is combined with standard optimization and search methods — namely gradient descent and simulated annealing— in order to study the reductions possible in experimental iterations. It is shown that the decision support methodology significantly reduces the number of experiments necessary to find the maximum power solution and thus offers a potentially significant cost saving to hardware-in-the-loop experimentation.
  • Mathematical model of a constructional coanda effect nozzle.

    Trancossi, Michele; Stewart, Jill; Subhash, M; Angeli, Diego; Sheffield Hallam University (Physics Society of Iran., 2016)
    This paper analyses the ACHEON Coanda effect nozzle for aircraft propulsion, based on the dynamic equilibrium of two jet streams. The ACHEON concept, and, in particular, the HOMER nozzle, which is its main component, are presented, together with the literature milestones from which the idea originally stems. A subsystem analysis inspired by the principles of Constructal Theory is presented for the current architecture. A mathematical model of a 2D case of the system is developed, focusing on the combined effect of the mixing of the two streams and the Coanda adhesion over a convex surface. A validation of the model is also reported, based on 2D CFD analyses, under the hypothesis of incompressible flow. Results highlight that, in spite of its relative simplicity, the model produces accurate results.
  • Constructal design of an entropic wall With circulating water inside.

    Trancossi, Michele; Stewart, Jill; Dumas, Antonio; Madonia, Mauro; Marques, Jose Pascoa; Sheffield Hallam University (ASME, 2016-04-26)
    An entropic wall with circulating water inside could be a solution for acclimatizing a new building with high-energy efficiency and high levels of internal comfort. If circulating water is thermally stabilized by exchanging in the ground such has it happens in geothermal plants, a thermal shield could be realized keeping walls in comfort conditions and minimizing energy needs for further temperature regulations. This paper presents optimization guidelines of such a wall with the objective of maximizing the performances of the wall for reaching optimal internal wellness conditions. Optimization has been realized by a constructal law based method, which has been personalized by a step-by-step process and has been named constructal design for efficiency (CDE). The optimization of the system has been produced at different levels. It starts from a preliminary analysis at system levels, which allow defining the best objectives that could be reached. After this preliminary process, the system has been divided into modules, and the critical ones which have higher influence on the performances of the system have been evaluated. This analysis has been coupled also with an industrial analysis with the goal of defining an effective layout, which could be also manufactured with acceptable costs. The result has produced a final solution with a very good compromise between energetic performances and minimization of costs at industrial level. The results open interesting perspectives for the constructal law to become the core of an effective methodology of an industrial design which can couple perfectly with the modular approach which is currently the major part of industrial companies.

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