Zeitschriftenartikel: „Optimisation de codes parallèles“

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Dai, Jingke, Xiao Chen, Fenggan Zhang und Kai Kang. „Optimisation design of systematic fountain codes on fading channels“. IET Communications 13, Nr. 20 (19.12.2019): 3369–76. http://dx.doi.org/10.1049/iet-com.2019.0426.

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Li, S. F., J. Chen und L. Q. Zhang. „Optimisation of complete complementary codes in MIMO radar system“. Electronics Letters 46, Nr. 16 (2010): 1157. http://dx.doi.org/10.1049/el.2010.1394.

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Orr, John, Ana Bras und Tim Ibell. „Effectiveness of design codes for life cycle energy optimisation“. Energy and Buildings 140 (April 2017): 61–67. http://dx.doi.org/10.1016/j.enbuild.2017.01.085.

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4

Bird, Robert F., Patrick Gillies, Michael R. Bareford, Andy Herdman und Stephen Jarvis. „Performance Optimisation of Inertial Confinement Fusion Codes using Mini-applications“. International Journal of High Performance Computing Applications 32, Nr. 4 (02.11.2016): 570–81. http://dx.doi.org/10.1177/1094342016670225.

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Despite the recent successes of nuclear energy researchers, the scientific community still remains some distance from being able to create controlled, self-sustaining fusion reactions. Inertial Confinement Fusion (ICF) techniques represent one possible option to surpass this barrier, with scientific simulation playing a leading role in guiding and supporting their development. The simulation of such techniques allows for safe and efficient investigation of laser design and pulse shaping, as well as providing insight into the reaction as a whole. The research presented here focuses on the simulation code EPOCH, a fully relativistic particle-in-cell plasma physics code concerned with faithfully recreating laser-plasma interactions at scale. A significant challenge in developing large codes like EPOCH is maintaining effective scientific delivery on successive generations of high-performance computing architecture. To support this process, we adopt the use of mini-applications – small code proxies that encapsulate important computational properties of their larger parent counterparts. Through the development of a mini-application for EPOCH (called miniEPOCH), we investigate a variety of the performance features exhibited in EPOCH, expose opportunities for optimisation and increased scientific capability, and offer our conclusions to guide future changes to similar ICF codes.

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He, Ruichun, Changxi Ma, Cunrui Ma, Wei Zhang und Qiang Xiao. „Optimisation algorithm for logistics distribution route based on Prufer codes“. International Journal of Wireless and Mobile Computing 9, Nr. 2 (2015): 205. http://dx.doi.org/10.1504/ijwmc.2015.072573.

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Yang, Jin, Zhaokun Qiu, Weidong Jiang und Xiang Li. „Poly‐phase codes optimisation for multi‐input–multi‐output radars“. IET Signal Processing 7, Nr. 2 (April 2013): 93–100. http://dx.doi.org/10.1049/iet-spr.2012.0195.

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Weng, Tien-hsiung, und Barbara Chapman. „Towards optimisation of openMP codes for synchronisation and data reuse“. International Journal of High Performance Computing and Networking 1, Nr. 1/2/3 (2004): 43. http://dx.doi.org/10.1504/ijhpcn.2004.007564.

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Träff, Erik A., Anton Rydahl, Sven Karlsson, Ole Sigmund und Niels Aage. „Simple and efficient GPU accelerated topology optimisation: Codes and applications“. Computer Methods in Applied Mechanics and Engineering 410 (Mai 2023): 116043. http://dx.doi.org/10.1016/j.cma.2023.116043.

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Srijuntongsiri, Gun, und Stanislav S. Makhanov. „Optimisation of five-axis machining G-codes in the angular space“. International Journal of Production Research 53, Nr. 11 (09.10.2014): 3207–27. http://dx.doi.org/10.1080/00207543.2014.965421.

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Deng, Dachun, Dazhuan Xu und Shengkai Xu. „Optimisation design of systematic LT codes over AWGN multiple access channel“. IET Communications 12, Nr. 11 (17.07.2018): 1351–58. http://dx.doi.org/10.1049/iet-com.2017.1063.

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Mirrezaei, S. M. „Towards systematic Luby transform codes: optimisation design over binary erasure channel“. Electronics Letters 56, Nr. 11 (Mai 2020): 550–53. http://dx.doi.org/10.1049/el.2019.4258.

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Volkel, Benedikt, Matteo Concas, Sandro Wenzel und Andreas Morsch. „A parameter optimisation toolchain for Monte Carlo detector simulation“. EPJ Web of Conferences 295 (2024): 03003. http://dx.doi.org/10.1051/epjconf/202429503003.

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Monte Carlo detector transport codes are one of the backbones in high-energy physics computing. They simulate the transport of a large variety of different particle types through complex detector geometries based on different physics models. Those simulations are usually configurable through a large set of parameters allowing for some tuning on the client side. Often, tuning the physics accuracy on the one hand and optimising the resource needs on the other hand are competing requirements. In this area, we are presenting a toolchain to tune Monte Carlo transport codes which is capable of automatically optimising large sets of parameters based on user-defined metrics. The toolchain consists of two central components. Firstly, the MCReplayEngine which is a quasi-Monte-Carlo transport engine able to fast replay pre-recorded MC steps. This engine for instance allows one to study the impact of parameter variations on quantities such as hits without the need to perform new full simulations. Secondly, it consists of an automatic and generic parameter optimisation framework called O2Tuner. The toolchain’s application in concrete use-cases will be presented. Its first application in ALICE led to a reduction of CPU time of Monte Carlo detector transport by 30%. In addition, further possible scenarios will be discussed.

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Farrelly, Terry, David K. Tuckett und Thomas M. Stace. „Local tensor-network codes“. New Journal of Physics 24, Nr. 4 (01.04.2022): 043015. http://dx.doi.org/10.1088/1367-2630/ac5e87.

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Abstract Tensor-network codes enable the construction of large stabilizer codes out of tensors describing smaller stabilizer codes. An application of tensor-network codes was an efficient and exact decoder for holographic codes. Here, we show how to write some topological codes, including the surface code and colour code, as simple tensor-network codes. We also show how to calculate distances of stabilizer codes by contracting a tensor network. The algorithm actually gives more information, including a histogram of all logical coset weights. We prove that this method is efficient in the case of stabilizer codes encoded via local log-depth circuits in one dimension and holographic codes. Using our tensor-network distance calculator, we find a modification of the rotated surface code that has the same distance but fewer minimum-weight logical operators by ‘doping’ the tensor network, i.e., we break the homogeneity of the tensor network by locally replacing tensors. For this example, this corresponds to an improvement in successful error correction of almost 2% against depolarizing noise (in the perfect-measurement setting), but comes at the cost of introducing three higher-weight stabilizers. Our general construction lets us pick a network geometry (e.g., a Euclidean lattice in the case of the surface code), and, using only a small set of seed codes (constituent tensors), build extensive codes with the potential for optimisation.

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Zehua, Yu, Li Jun, Zhang Yuhong und Liao Guisheng. „Mainlobe interference suppression via transmit phase codes optimisation in MIMO radar systems“. Electronics Letters 53, Nr. 21 (Oktober 2017): 1427–29. http://dx.doi.org/10.1049/el.2017.2787.

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Jayasooriya, Sachini, Mahyar Shirvanimoghaddam, Lawrence Ong und Sarah J. Johnson. „Joint optimisation technique for multi-edge type low-density parity-check codes“. IET Communications 11, Nr. 1 (05.01.2017): 61–68. http://dx.doi.org/10.1049/iet-com.2016.0287.

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Razali, Samirah, Kamaruddin Mamat und Nor Shahniza Kamal Bashah. „Multiple error correction towards optimisation of energy in sensor network“. Indonesian Journal of Electrical Engineering and Computer Science 13, Nr. 3 (01.03.2019): 1208. http://dx.doi.org/10.11591/ijeecs.v13.i3.pp1208-1220.

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<span>Hybrid ARQ (HARQ) is among the optimum error controls implemented in Wireless Sensor Network as it reduces the overhead from retransmission and error correcting codes. The advancement in WSN includes the usage of high number of nodes and the increase in traffic with large data transmitted among the nodes had concerned the need for a new approach in error control algorithm. This paper proposed the multiple error correction based on HARQ process to aid the changes in channel with proper error correction assignment towards optimising the performances of WSN in terms of bit error rates, remaining energy, and latency for different types of congestion and channel conditions. In this study, we have developed the channel adaptation algorithm that can adapt to sudden changes and demonstrated the optimal error correcting codes as well as adjustment on the transmit power for the given channel condition and congestion presented. From the result analysed, the optimisation between the remaining energy and Bit Error rates happened on the basis of adapting to these different channel condition and congestion to minimize redundancies appended. From the result obtained, we concluded that by using multiple error correction algorithm with the aid of adjustment on the transmit power, the remaining energy can be optimised together with Bit Error rates and the excessive redundancies can be reduced</span>

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Mas Magre, Isidre, Rogeli Grima Torres, José María Cela Espín und Julio Gutierrez Moreno. „The NOMAD mini-apps: A suite of kernels from ab initio electronic structure codes enabling co-design in high-performance computing“. Open Research Europe 4 (19.02.2024): 35. http://dx.doi.org/10.12688/openreseurope.16920.1.

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This article introduces a suite of mini-applications (mini-apps) designed to optimise computational kernels in ab initio electronic structure codes. The suite is developed from flagship applications participating in the NOMAD Center of Excellence, such as the ELPA eigensolver library and the GW implementations of the exciting, Abinit, and FHI-aims codes. The mini-apps were identified by targeting functions that significantly contribute to the total execution time in the parent applications. This strategic selection allows for concentrated optimisation efforts. The suite is designed for easy deployment on various High-Performance Computing (HPC) systems, supported by an integrated CMake build system for straightforward compilation and execution. The aim is to harness the capabilities of emerging (post)exascale systems, which necessitate concurrent hardware and software development — a concept known as co-design. The mini-app suite serves as a tool for profiling and benchmarking, providing insights that can guide both software optimisation and hardware design. Ultimately, these developments will enable more accurate and efficient simulations of novel materials, leveraging the full potential of exascale computing in material science research.

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Ait Ouchaoui, A., M. Nassraoui und B. Radi. „Numerical investigation of the effect of topology optimisation methods parameters in the topology quality, the strength, and the computational cost“. Archives of Materials Science and Engineering 123, Nr. 2 (01.10.2023): 55–71. http://dx.doi.org/10.5604/01.3001.0054.2492.

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The literature abounds with many distinct topology optimisation methods, many of which share common parameter configurations. This study demonstrates that alternative parameter configurations may produce better results than common parameters. Additionally, we try to answer two fundamental questions: identifying the most effective topology optimisation method and determining the optimal parameter selection within this optimisation method. In order to respond to these questions, we conducted a comparative and objective analysis of topology optimisation methods.This paper evaluates four prominent topology optimisation methodologies, SIMP, RAMP, BESO, and LSM, based on three essential criteria: structural strength, topology quality, and computational cost. We conducted an in-depth examination of 12,500 topology optimisation results spanning a broad range of critical parameter values. These outcomes were generated using MATLAB codes. In the meantime, we comprehensively compared our findings with the existing literature on this subject.As predicted, our chosen parameters had a substantial effect on the topology quality, structural strength, and computational cost of the topology optimisation outcomes. Across the 12,500 results, many parameter combinations appeared to produce favourable results compared to conventional parameters commonly found in the existing literature.This study focuses exclusively on four specific topology optimisation methods; however, its findings may be extrapolated to apply to other methodologies. Additionally, while it extensively examines the effects of parameters on topology quality, strength, and computational cost, it does not encompass an exploration of these parameters' impacts on other performance criteria.Novel parameter configurations for topology optimisation have been identified, yielding enhanced outcomes in terms of topology quality, structural strength, and computational efficiency.

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Ryazanov, V. V. „Optimisation of multiclass supervised classification based on using output codes with error-correcting“. Pattern Recognition and Image Analysis 26, Nr. 2 (April 2016): 262–65. http://dx.doi.org/10.1134/s1054661816020176.

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Chen, X., und F. C. M. Lau. „Optimisation of low-density parity-check codes with deterministic unequal error protection properties“. IET Communications 5, Nr. 11 (22.07.2011): 1560–65. http://dx.doi.org/10.1049/iet-com.2010.0677.

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21

Dütsch, Nicolas. „Code optimisation for lossless compression of binary memoryless sources based on FEC codes“. European Transactions on Telecommunications 17, Nr. 2 (2006): 219–29. http://dx.doi.org/10.1002/ett.1103.

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Valetov, Eremey. „Beamline design and optimisation for high intensity muon beams at PSI“. Journal of Physics: Conference Series 2420, Nr. 1 (01.01.2023): 012053. http://dx.doi.org/10.1088/1742-6596/2420/1/012053.

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Abstract The High Intensity Muon Beams (HIMB) project at the Paul Scherrer Institute (PSI) will provide muon intensities of the order of 1010 muons/s for particle physics and material science experiments, two orders of magnitude higher than the state of the art, which is currently available also at PSI. In particle transport simulations for the HIMB, we use G4beamline with measured + cross-sections and with variance reduction. We also use the codes COSY INFINITY, TRANSPORT, and TURTLE for some studies. We perform asynchronous Bayesian optimisation of the beamlines on a computing cluster using G4beamline and the optimisation package DeepHyper. We performed numerous studies for the design of the HIMB, and we produced various results, including the muon transmission, beam phase space, polarisation, and momentum spectrum.

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ONEL, Alexandru-Iulian, Oana-Iuliana POPESCU, Ana-Maria NECULAESCU, Tudorel-Petronel AFILIPOAE und Teodor-Viorel CHELARU. „Liquid rocket engine performance assessment in the context of small launcher optimisation“. INCAS BULLETIN 11, Nr. 3 (09.09.2019): 135–45. http://dx.doi.org/10.13111/2066-8201.2019.11.3.12.

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The paper presents a fast mathematical model that can be used to quickly asses the propulsive characteristics of liquid propelled rocket engines. The main propulsive parameters are computed using combustion surfaces obtained after a nonlinear data fitting analysis. This approach is much more time efficient than using standard codes which rely on frequent calls of the Fuel Combustion Charts and interpolating their data. The tool developed based on the proposed mathematical model can be used separately or it can be integrated in a multidisciplinary optimisation algorithm for a preliminary microlauncher design.

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Whitworth, Alex H., und Konstantinos Daniel Tsavdaridis. „Genetic Algorithm for Embodied Energy Optimisation of Steel-Concrete Composite Beams“. Sustainability 12, Nr. 8 (13.04.2020): 3102. http://dx.doi.org/10.3390/su12083102.

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The optimisation of structural performance is acknowledged as a means of obtaining sustainable structural designs. A minimisation of embodied energy of construction materials is a key component in the delivery of sustainable future designs. This study attempts to understand the relationship between embodied energy and structural form of composite floor plates for tall buildings, and how this form can be optimised to minimise embodied energy. As a search method based upon the principles of genetics and natural selection, genetic algorithms (GA) have previously been used as novel means of optimising composite beams and composite frames for cost and weight objective functions. Parametric design models have also been presented as optimisation tools to optimise steel floor plates for both cost and embodied carbon. In this study, a Matlab algorithm is presented incorporating MathWorks global optimisation toolbox GA and utilising Eurocode 4 design processes to optimise a composite beam for five separate objective functions: maximise span length; minimise beam cross-section; minimise slab depth; minimise weight; minimise deflected shape for each of the objective functions. Candidate designs are to be assessed for embodied energy to determine individual relationships. This study shows that it is possible to reduce the embodied energy of steel–concrete composite beams by genetic algorithm optimisation whilst remaining compliant to given design codes.

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Xu, Guangping, Qunfang Mao, Huan Li und Shengli Li. „Towards optimisation of replicated erasure codes for efficient cooperative repair in cloud storage systems“. International Journal of Computational Science and Engineering 16, Nr. 2 (2018): 108. http://dx.doi.org/10.1504/ijcse.2018.090444.

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Li, Shengli, Huan Li, Qunfang Mao und Guangping Xu. „Towards optimisation of replicated erasure codes for efficient cooperative repair in cloud storage systems“. International Journal of Computational Science and Engineering 16, Nr. 2 (2018): 108. http://dx.doi.org/10.1504/ijcse.2018.10011519.

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Mowatt, G. A., D. J. Loader und C. H. Arbuthnot. „The use and potential use of reliability engineering for offshore structures“. Aeronautical Journal 92, Nr. 911 (Januar 1988): 9. http://dx.doi.org/10.1017/s0001924000021783.

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This paper presents a review of the current status and potential future use of reliability methods in the design, fabrication and operation of offshore oil production platforms. An overview of the traditional design process is presented and key areas where reliability methods have contributed to the development of codes of practice are described. Future applications in the design stage include the optimisation of framing configurations and the treatment of uncertainties in basic design parameters.

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Franco Caballero, Pablo Daniel, und Francisco José García Aguilera. „Evaluation for QR codes in environmental museums“. Global Journal of Information Technology: Emerging Technologies 9, Nr. 2 (31.10.2019): 29–32. http://dx.doi.org/10.18844/gjit.v9i2.4268.

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The continued use of digital devices, such as smartphones and tablets, has substantially changed the way we communicate and acquire knowledge. Museums are a key element in our society and a source of culture. Updating the method of transmission of museum culture is needed, so technologies related to the Internet have been integrated into the exposed elements. One of the most widespread methods among innovation trends in museums is the use of Quick Response (QR) codes for the transmission of additional information to the exposed elements. The case of the Alborania Museum, being a museum of environmental education, has live animals in veterinary treatment, so the information on the available animals is constantly changing. Establishing posters would have an environmental impact that is against the museum's ethics, so QRs are the best way to present dynamic content with low environmental impact. This article proposes an evaluation of an educational innovation project in the Alborania Museum of Malaga through the Contribution Analysis, in order to verify the value of QR codes as an improvement in the transmission of environmental education. The results show a very good acceptance and usability in this museistic context. The conclusions of this study are relevant to the optimisation of environmental museum information. Keywords: QR code, museum, evaluation, contribution analysis, ICT, environmental education.

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Kapageridis, I., A. Apostolikas, S. Pappas und I. Zevgolis. „Use of mine planning software for the evaluation of resources and reserves of a sedimentary nickel deposit“. Bulletin of the Geological Society of Greece 47, Nr. 4 (05.09.2013): 1980. http://dx.doi.org/10.12681/bgsg.11021.

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The use of mine planning software in the evaluation of deposits and estimation of mineral resources and reserves has become widespread and is considered a prerequisite for the reporting of reserves according to international reporting standards and codes. The main principles of operation and application of these codes are transparency of reported material, the relevance of reported information (materiality) and the competence of people involved in producing the reports. The application of specialised mine planning software described in this paper currently takes place at operational mines of sedimentary nickel deposits in Central Evia, Greece. It involves all stages of processing of exploration data including entry, analysis, processing and modelling of data, geostatistical estimation of quantities and qualities of mineral resources and mineral reserves, and the design, optimisation and scheduling of mining operations.

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Gonzalez, L. F., D. S. Lee, K. Srinivas und K. C. Wong. „Single and multi–objective UAV aerofoil optimisation via hierarchical asynchronous parallel evolutionary algorithm“. Aeronautical Journal 110, Nr. 1112 (Oktober 2006): 659–72. http://dx.doi.org/10.1017/s0001924000001524.

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Abstract Unmanned aerial vehicle (UAV) design tends to focus on sensors, payload and navigation systems, as these are the most expensive components. One area that is often overlooked in UAV design is airframe and aerodynamic shape optimisation. As for manned aircraft, optimisation is important in order to extend the operational envelope and efficiency of these vehicles. A traditional approach to optimisation is to use gradient-based techniques. These techniques are effective when applied to specific problems and within a specified range. These methods are efficient for finding optimal global solutions if the objective functions and constraints are differentiable. If a broader application of the optimiser is desired, or when the complexity of the problem arises because it is multi-modal, involves approximation, is non-differentiable, or involves multiple objectives and physics, as it is often the case in aerodynamic optimisation, more robust and alternative numerical tools are required. Emerging techniques such as evolutionary algorithms (EAs) have been shown to be robust as they require no derivatives or gradients of the objective function, have the capability of finding globally optimum solutions among many local optima, are easily executed in parallel, and can be adapted to arbitrary solver codes without major modifications. In this paper, the formulation and application of a evolutionary technique for aerofoil shape optimisation is described. Initially, the paper presents an introduction to the features of the method and a short discussion on multi-objective optimisation. The method is first illustrated on its application to mathematical test cases. Then it is applied to representative test cases related to aerofoil design. Results indicate the ability of the method for finding optimal solutions and capturing Pareto optimal fronts.

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Matuszewski, Leszek. „Ring thruster — a preliminary optimisation study“. Polish Maritime Research 16, Nr. 1 (01.01.2009): 43–46. http://dx.doi.org/10.2478/v10012-008-0009-5.

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Ring thruster — a preliminary optimisation study The ring thruster is a new type of propeller, for which there is no experimental data to verify analytical design calculations. A significant feature of the ring thruster is the absence of a shaft. Propeller blades are mounted to the ring rotating inside the housing, which has the shape of a nozzle. For this reason the ring thruster is closest, with respect to both the construction and principle of operation, to the Kort nozzle propeller. The absence of a shaft and no gap between the blades and the nozzle make it impossible to fully relay on results obtained from Kort nozzle propeller examination. What is more, the already existing computer codes developed for designing Kort nozzle propellers cannot be directly used for designing ring thrusters either. That is why for this purpose a new code determining hydrodynamic characteristics based on the theory of the vortex lifting surface will be used. When using the above method, some differences between calculated and experimentally recorded results are expected to be observed. To a significant extent, the level of the torque taken by the thruster will be affected by drag of the rotating ring to which the blades are fixed. Examining a propeller equipped with a rotating ring has revealed that the expected torque increment may reach as much as a few per cent, at the comparable level of axial force (thrust). At the present stage of ring propeller investigations there is no data available on how to shape the ring propeller blades. Possible comparison calculations, done using the existing computer code, will allow, the most, the shape of the blades to be determined for preliminary tests in the cavitation tunnel and on a self-propelled model. And only the results obtained in these tests will provide opportunities for verification of preliminary design calculations. It should be stressed, however, that developing design procedures for this type of propellers will require additional optimisation calculations, with further experimental verification. And this should be the subject of separate investigations.

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Singal, Tanmay, Che Chiang, Eugene Hsu, Eunsang Kim, Hsi-Sheng Goan und Min-Hsiu Hsieh. „Counting stabiliser codes for arbitrary dimension“. Quantum 7 (06.07.2023): 1048. http://dx.doi.org/10.22331/q-2023-07-06-1048.

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In this work, we compute the number of [[n,k]]d stabilizer codes made up of d-dimensional qudits, for arbitrary positive integers d. In a seminal work by Gross \cite{Gross2006} the number of [[n,k]]d stabilizer codes was computed for the case when d is a prime (or the power of a prime, i.e., d=pm, but when the qudits are Galois-qudits). The proof in \cite{Gross2006} is inapplicable to the non-prime case. For our proof, we introduce a group structure to [[n,k]]d codes, and use this in conjunction with the Chinese remainder theorem to count the number of [[n,k]]d codes. Our work overlaps with \cite{Gross2006} when d is a prime and in this case our results match exactly, but the results differ for the more generic case. Despite that, the overall order of magnitude of the number of stabilizer codes scales agnostic of whether the dimension is prime or non-prime. This is surprising since the method employed to count the number of stabilizer states (or more generally stabilizer codes) depends on whether d is prime or not. The cardinality of stabilizer states, which was so far known only for the prime-dimensional case (and the Galois qudit prime-power dimensional case) plays an important role as a quantifier in many topics in quantum computing. Salient among these are the resource theory of magic, design theory, de Finetti theorem for stabilizer states, the study and optimisation of the classical simulability of Clifford circuits, the study of quantum contextuality of small-dimensional systems and the study of Wigner-functions. Our work makes available this quantifier for the generic case, and thus is an important step needed to place results for quantum computing with non-prime dimensional quantum systems on the same pedestal as prime-dimensional systems.

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Wang, Q., J. Chen, G. Fu, D. Duan und H. Zhao. „A methodology for optimisation design and analysis of stratosphere airship“. Aeronautical Journal 113, Nr. 1146 (August 2009): 533–40. http://dx.doi.org/10.1017/s0001924000003183.

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Abstract This paper presents a methodology for studying the feasibility of stratosphere airship for high altitude long endurance missions and arriving at the baseline specifications of conventional configuration of stratosphere airship, given the performance and operational requirements. Based on this methodology, the AODAP platform (Airship Optimisation Design and Analysis Platform) was developed. Some innovative concepts used in AODAP that are different from previous methods and codes are presented. The shape optimisation of airship was introduced into the design process, and several optimum objectives can be selected including minimum drag, minimum weight and composite objective based on MDO (Multidisciplinary Design Optimisation). The methodology was validated for other design concepts previously developed for similar missions and also was compared to a low altitude vehicle. The baseline specifications of stratosphere airships designed for various shapes using this methodology are presented. The results of sensitivity analyses for a specified airship are discussed, and the sensitivity of airship length with some critical parameters including area density of envelope fabric, area density of solar cell, efficiency of solar cell and efficiency of fuel cell for the specified shape is also provided.

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Misev, Cyril, und Nicholas J. Hills. „Steepest descent optimisation of Runge–Kutta coefficients for second order implicit finite volume CFD codes“. Journal of Computational Physics 354 (Februar 2018): 576–92. http://dx.doi.org/10.1016/j.jcp.2017.09.008.

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Kunakote, Tawatchai, und Sujin Bureerat. „Surrogate-Assisted Multiobjective Evolutionary Algorithms for Structural Shape and Sizing Optimisation“. Mathematical Problems in Engineering 2013 (2013): 1–13. http://dx.doi.org/10.1155/2013/695172.

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The work in this paper proposes the hybridisation of the well-established strength Pareto evolutionary algorithm (SPEA2) and some commonly used surrogate models. The surrogate models are introduced to an evolutionary optimisation process to enhance the performance of the optimiser when solving design problems with expensive function evaluation. Several surrogate models including quadratic function, radial basis function, neural network, and Kriging models are employed in combination with SPEA2 using real codes. The various hybrid optimisation strategies are implemented on eight simultaneous shape and sizing design problems of structures taking into account of structural weight, lateral bucking, natural frequency, and stress. Structural analysis is carried out by using a finite element procedure. The optimum results obtained are compared and discussed. The performance assessment is based on the hypervolume indicator. The performance of the surrogate models for estimating design constraints is investigated. It has been found that, by using a quadratic function surrogate model, the optimiser searching performance is greatly improved.

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Xing, Y. „Burst pressure design of the cargo tank used in a novel large subsea freight-glider“. IOP Conference Series: Materials Science and Engineering 1201, Nr. 1 (01.11.2021): 012014. http://dx.doi.org/10.1088/1757-899x/1201/1/012014.

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Abstract This paper presents the burst pressure design of the cargo tank used in the University of Stavanger (UiS) Subsea Freight-Glider (USFG). The USFG is an innovative large underwater cargo glider drone that is 50 m long and has a DWT of 1500 ton. It uses variable-buoyancy propulsion instead of traditional propellers for movement. This is an extremely efficient propulsion method and allows the USFG to achieve an average energy consumption of less than 10 kW. Structural weight is a premium as the USFG is required to be neutrally buoyant in water. Therefore, the design of the cargo tank which is the largest component in the USFG needs to be optimal for minimal structural weight. One approach used in design optimisation is to utilise design codes and/or methods that are more precise and therefore allow for lower safety margins. This approach will be investigated in this paper for the burst pressure design of the cargo tank. The different parts of ASME BPVC codes will be compared. The sensitivity of the codes to changes in design parameters is also investigated. Lastly, some comments on the use of reliability methods to further optimise the design are also presented.

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Szkutnik-Rogoż, Joanna, Jarosław Ziółkowski, Jerzy Małachowski und Mateusz Oszczypała. „Mathematical Programming and Solution Approaches for Transportation Optimisation in Supply Network“. Energies 14, Nr. 21 (26.10.2021): 7010. http://dx.doi.org/10.3390/en14217010.

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The problem of transport is a special type of mathematical programming designed to search for the optimal distribution network, taking into account the set of suppliers and the set of recipients. This article proposes an innovative approach to solving the transportation problem and devises source codes in GNU Octave (version 3.4.3) to avoid the necessity of carrying out enormous calculations in traditional methods and to minimize transportation costs, fuel consumption, and CO2 emission. The paper presents a numerical example of a solution to the transportation problem using: the northwest corner, the least cost in the matrix, the row minimum, and Vogel’s Approximation Methods (VAM). The joint use of mathematical programming and optimization was applicable to real conditions. The transport was carried out with medium load trucks. Both suppliers and recipients of materials were located geographically within the territory of the Republic of Poland. The presented model was supported by a numerical example with interpretation and visualization of the obtained results. The implementation of the proposed solution enables the user to develop an optimal transport plan for individually defined criteria.

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Hong, Shaohua, Qiwang Chen und Lin Wang. „Performance analysis and optimisation for edge connection of JSCC system based on double protograph LDPC codes“. IET Communications 12, Nr. 2 (30.01.2018): 214–19. http://dx.doi.org/10.1049/iet-com.2017.0787.

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Toropov, A. A., und E. Benfenati. „QSAR modelling of aldehyde toxicity by means of optimisation of correlation weights of nearest neighbouring codes“. Journal of Molecular Structure: THEOCHEM 676, Nr. 1-3 (Mai 2004): 165–69. http://dx.doi.org/10.1016/j.theochem.2004.01.023.

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De Domenico, Dario, und Iman Hajirasouliha. „Multi-level performance-based design optimisation of steel frames with nonlinear viscous dampers“. Bulletin of Earthquake Engineering 19, Nr. 12 (21.06.2021): 5015–49. http://dx.doi.org/10.1007/s10518-021-01152-7.

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AbstractThis paper presents a practical multi-level performance-based optimisation method of nonlinear viscous dampers (NVDs) for seismic retrofit of existing substandard steel frames. A Maxwell model is adopted to simulate the behaviour of the combined damper-supporting brace system, with a fractional power-law force–velocity relationship for the NVDs, while a distributed-plasticity fibre-based section approach is used to model the beam-column members thus incorporating the nonlinearity of the parent steel frame in the design process. The optimum height-wise distribution of the damping coefficients of NVDs satisfying given performance requirements is identified via a uniform damage distribution (UDD) design philosophy. The efficiency of the proposed multi-level performance-based design optimisation is illustrated through nonlinear time-history analysis of 3-, 7- and 12-storey steel frames under both artificial and natural spectrum-compatible earthquakes. Sensitivity analysis is performed to investigate the effects of initial height-wise damping distribution, convergence factor and uncertainty in design ground-motion prediction on the optimisation strategy. The efficiency of the final optimum design solution is also investigated by using drift-based, velocity-based, and energy-based UDD approaches to identify the most efficient performance index parameter for optimisation purposes. It is found that regardless of the selected performance parameter, the optimum damping distribution identified by the proposed methodology leads to frames exhibiting lower maximum inter-storey drift, local damage (maximum plastic rotation) and global damage index compared to an equal-cost uniform damping distribution. However, using drift-based UDD approach generally results in a better seismic performance. It is shown that the proposed UDD optimisation method can be efficiently used to satisfy multiple performance objectives at different intensity levels of the earthquake excitation, in line with performance-based design recommendations of current seismic codes. The proposed method is easy to implement for practical design purposes and represents a simple yet efficient tool for optimum seismic retrofit of steel frames with NVDs.

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Zhang, Mu, Zulin Wang, Zhe Liu, Qin Huang und Shuai Yuan. „Density optimisation of generator matrices of quasi-cyclic low-density parity-check codes and their rank analysis“. IET Communications 8, Nr. 14 (25.09.2014): 2547–55. http://dx.doi.org/10.1049/iet-com.2014.0178.

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Bulut Cebecioglu, Berna. „RaptorQ codes aided secure data delivery strategy for vehicular networks“. at - Automatisierungstechnik 70, Nr. 2 (01.02.2022): 154–63. http://dx.doi.org/10.1515/auto-2020-0146.

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Abstract This paper deals with security issues in the presence of an eavesdropper for a vehicular scenario. The proposed secure data delivery scheme implements Fountain Codes, namely RaptorQ (RQ) codes, at the application layer (AL) to increase communication security against eavesdroppers’ attacks. For RQ coded transmission scheme, the receiver has to collect a sufficient number of coded packets to reconstruct the original source data. Secure delivery can be achieved if the legitimate user obtains enough RQ coded packets before the eavesdropper does. To satisfy this condition, it is proposed to use a road side unit (RSU) cooperation method when the eavesdropper has better channel conditions than the legitimate user to scatter the coded packets from multiple RSUs. The aim is to reduce the probability that the eavesdropper receives the sufficient number of coded packets and recover the source data before the legitimate user. An optimisation framework which jointly selects the RQ code rate at the AL and Modulation and Coding Scheme (MCS) at the physical (PHY) layer to ensure the secure data transmission by allowing the user to decode the file with a certain probability of decoding success while minimising the intercept probability at the eavesdropper is presented. To evaluate the proposed system, a realistic end-to-end system level simulator is developed. Simulation results show that the proposed scheme can provide secure and efficient data transmission over vehicular networks by significantly reducing the intercept probability at the eavesdropper.

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Oke, Sunday, Stephen Chidera Nwafor und Chris Abiodun Ayanladun. „Optimisation of Casting Geometries for A356 Alloy Composites Reinforced with Organic Materials using Box-Behnken Design Methodology“. Journal of Applied Science & Process Engineering 7, Nr. 2 (30.10.2020): 524–53. http://dx.doi.org/10.33736/jaspe.2389.2020.

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In an earlier article, the central composite design was applied to the determination of geometrical features of casts in a two-phase transformation process to produce the wheel covers of automobiles whereby the A356 alloy is reinforced with organic substances for composite property enhancement. This article reexamines the assumptions in that circumstance to revise and expand the optimisation through the response surface methodology to a new method, Box-Behnken design (BBD), to facilitate a comprehensive treatment of the sand casting product parameters. Casting geometrical optimisation can be modelled to involve lengths, breadths, widths, heights, densities of casts and weight loss, varied at three discrete levels. The parameters are translated into codes (–1,0,1) with specified actual, minimum and maximum values. The framework, validated by published literature data, indicates its feasibility in a real-life circumstance. This article assessed the effects of the casting geometry parameters on the responses. Besides, it examined the accuracy of the parameters to predict in the regression models deployed. It was concluded that the BBD and the regression models are adequate and predict correctly. The BBD can be applied by composite developers to improve casting dimensional accuracy and economics.

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Lecordix, J. L., J. M. Gippet und J. L. Duparcq. „Design of an advanced nacelle for a very high bypass ratio engine“. Aeronautical Journal 96, Nr. 960 (Dezember 1992): 387–94. http://dx.doi.org/10.1017/s0001924000025082.

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AbstractThe next challenge for future engines is to increase the bypass ratio in order to improve the propulsive efficiency. These very high bypass ratio engines improve the fuel consumption but create new technical challenges. These challenges include the fact that larger engines require bigger nacelles, hence the external drag and weight increase; furthermore the installation of these engines on civil aircraft is more challenging. Therefore important work has been carried out to optimise the design of these new nacelles and their installation on the airframe.The present work is based on a new engine, with a very high bypass ratio. For this engine Snecma has designed an advanced nacelle with a low diameter-low length fan cowl and a core cowl mounted thrust reverser. A very short secondary flow nozzle is required to improve accessibility to the core engine and its accessories. The fan cowl length is dramatically reduced.Different solutions were investigated to design the inlet and the fan cowl. Based on 2D potential inverse codes and 3D Euler codes, CFD calculations were made to optimise the aerodynamic lines for cruise conditions while keeping good off-design performance. A highly challenging exhaust nozzle was designed to maintain good efficiency with very tough geometric constraints. For this Snecma used 2D Navier-Stokes CFD codes. New reverse systems were studied for this type of nacelle, for example core cowl mounted thrust reversers. The optimisation of these highly 3D geometries was performed using 2D and 3D Navier-Stokes calculations.

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Tegola, Antonio La, Luciano Ombres und Corrado Pecora. „Minimum Weight Design of Reticular Space Structures: A Computer Aided System“. International Journal of Space Structures 9, Nr. 4 (Dezember 1994): 179–89. http://dx.doi.org/10.1177/026635119400900401.

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In this work, by the definition of a computer aided system, we describe an optimisation procedure of reticular space structures based on the search of the minimum volume of the bars. The design system is based on classical methods of solution of minimum problems, the Feasible Regulation Method and the Optimality Criteria Method, adapted to this problem of defining again the stability and convergence parameters. The research of the optimal solution is carried out with reference to popular commercial sections (tubes) taking into account dimensional constrains imposed by the industrial production and design codes. The results of some numerical examples show the versatility and the efficiency of the design system with regard to reticular structures of any shape and dimension.

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Buliński, P., J. Smołka, S. Golak, R. Przyłucki, L. Blacha, R. Białecki, M. Palacz und G. Siwiec. „Effect Of Turbulence Modelling In Numerical Analysis Of Melting Process In An Induction Furnace“. Archives of Metallurgy and Materials 60, Nr. 3 (01.09.2015): 1575–80. http://dx.doi.org/10.1515/amm-2015-0275.

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AbstractIn this paper, the velocity field and turbulence effects that occur inside a crucible of a typical induction furnace were investigated. In the first part of this work, a free surface shape of the liquid metal was measured in a ceramic crucible. Then a numerical model of aluminium melting process was developed. It took into account coupling of electromagnetic and thermofluid fields that was performed using commercial codes. In the next step, the sensitivity analysis of turbulence modelling in the liquid domain was performed. The obtained numerical results were compared with the measurement data. The performed analysis can be treated as a preliminary approach for more complex mathematical modelling for the melting process optimisation in crucible induction furnaces of different types.

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Weatherburn, Christopher J. „Data quality in primary care, Scotland“. Scottish Medical Journal 66, Nr. 2 (21.02.2021): 66–72. http://dx.doi.org/10.1177/0036933021995965.

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Background and aims This project explores primary care data quality (DQ) across Scotland. Methods and results A survey was sent to primary care staff in winter 2019. National data regarding Quality and Outcomes Framework (QOF) performance indicators and the GP software system used was obtained, analysed with T-tests and Chi-squared tests. Overall QOF performance with non-financial incentives from 918 practices was 77%. There was no significant difference with overall QOF performance against GP system ( p = 0.46) or if the practice had a coder ( p = 0.06). From the survey, search systems that make it hard to search for particular codes was the most important barrier to DQ; 61% of respondents ( n = 491) felt there was particular information GPs should code, 16% of respondents stated that hospital discharge letters generally include corresponding codes and 9% for outpatient correspondence; 43% stated their practice had undertaken steps to improve DQ, training was the most common initiative, followed by workflow optimisation, dedicated coder(s), audit, guidelines and using code lists; 80% ( n = 475) of respondents had received training in using their GP system, an average of eight years ago. Conclusion Obtaining improved GP systems, training, agreeing what GPs should code and improving transfer of data should be explored.

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Smith, Paul N., Dave Hanlon, Geoff Dobson, Richard Hiles, Tim Fry, Magda Stefanowska, Simon Richards und Christophe Murphy. „ANSWERS® TOOLS FOR UNCERTAINTY QUANTIFICATION AND VALIDATION“. EPJ Web of Conferences 247 (2021): 15015. http://dx.doi.org/10.1051/epjconf/202124715015.

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ANSWERS® is developing a set of uncertainty quantification (UQ) tools for use with its major physics codes: WIMS/PANTHER (reactor physics), MONK (criticality and reactor physics) and MCBEND (shielding and dosimetry). The Visual Workshop integrated development environment allows the user to construct and edit code inputs, launch calculations, post-process results and produce graphs, and recently uncertainty quantification and optimisation tools have been added. Prior uncertainties due to uncertainties in nuclear data or manufacturing tolerances can be estimated using the sampling method or using the sensitivity options in the physics codes combined with appropriate covariance matrices. To aid the user in the choice of appropriate validation experiments, the MONK categorisation scheme and/or a similarity index can be used. An interactive viewer has been developed which allows the user to search through, and browse details of, over 2,000 MONK validation experiments that have been analysed from the ICSBEP and IRPhE validation sets. A Bayesian updating approach is used to assimilate the measured data with the calculated results. It is shown how this process can be used to reduce bias in calculated results and reduce the calculated uncertainty on those results. This process is illustrated by application to a PWR fuel assembly.

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Nguyen, Khuong Le, Thanh Tu Do, Giang Huu Nguyen und Afaq Ahmad. „Low-Code Application and Practical Implications of Common Machine Learning Models for Predicting Punching Shear Strength of Concrete Reinforced Slabs“. Advances in Civil Engineering 2023 (01.11.2023): 1–20. http://dx.doi.org/10.1155/2023/8853122.

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This paper investigates the effectiveness of machine learning (ML) models available in MATLAB Regression Learner app and MATLAB App Designer, both low-code applications, for accurately predicting punching shear strength (PSS) in reinforced concrete (RC) slabs. A database of 379 RC slab samples without transverse reinforcement was compiled from renowned publications. RandomSearch and Bayesian optimisation were employed for tuning hyperparameters. The performance of these models was compared with six empirical models, which included three current design codes, three equations from other researchers, and 227 finite-element simulations conducted by the authors. The ML models and finite-element method (FEM) demonstrated superior performance compared with the literature and practical codes. Furthermore, the results emphasised the exceptional performance of the Gaussian process regression (GPR) with optimised hyperparameters, exhibiting the best performance in validation, training, and testing datasets with R2 values of 0.95, 0.99, and 0.98, respectively. A user-friendly standalone application was developed, providing real-time predictions of the PSS using the two best-developed ML models, GPR and support vector machine (SVM), as well as six empirical models from the literature. This tool offers users flexibility in choosing the most appropriate model for their specific needs, delivering reliable, and accurate results for estimating the PSS of RC slabs.

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Milani, Simone, Giancarlo Calvagno, Riccardo Bernardini und Pamela Zontone. „Cross-Layer joint optimisation of FEC channel codes and Multiple Description Coding for video delivery over IEEE 802.11e links“. International Journal of Internet Protocol Technology 4, Nr. 1 (2009): 32. http://dx.doi.org/10.1504/ijipt.2009.024168.

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