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Moura, Henrique Gomes, Edson Costa Junior, Arcanjo Lenzi, and Vinicius Carvalho Rispoli. "On a Stochastic Regularization Technique for Ill-Conditioned Linear Systems." Open Engineering 9, no. 1 (2019): 52–60. http://dx.doi.org/10.1515/eng-2019-0008.
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AbstractKnowledge about the input–output relations of a system can be very important in many practical situations in engineering. Linear systems theory comes from applied mathematics as an efficient and simple modeling technique for input–output systems relations. Many identification problems arise from a set of linear equations, using known outputs only. It is a type of inverse problems, whenever systems inputs are sought by its output only. This work presents a regularization method, called random matrix method, which is able to reduce errors on the solution of ill-conditioned inverse problems by introducing modifications into the matrix operator that rules the problem. The main advantage of this approach is the possibility of reducing the condition number of the matrix using the probability density function that models the noise in the measurements, leading to better regularization performance. The method described was applied in the context of a force identification problem and the results were compared quantitatively and qualitatively with the classical Tikhonov regularization method. Results show the presented technique provides better results than Tikhonov method when dealing with high-level ill-conditioned inverse problems.
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Tawfiq, Kotb B., A. S. Mansour, and E. E. EL-Kholy. "Implementation of Ultra-Modified Symmetric Sequence Algorithm for Space Vector Modulation of Matrix Converter." International Journal of Applied Power Engineering (IJAPE) 7, no. 3 (2018): 264. http://dx.doi.org/10.11591/ijape.v7.i3.pp264-276.
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<span lang="EN-US">This paper proposes an ultra- modified symmetric sequence algoritm of space vector modulation of matrix converter. The ultra-modified technique improves the drawbacks of the modified one where it provides a reduction of the total harmonic distortion for both output voltage and output current. Some of the advantages of matrix converter are introduced in this paper. These advantages represented in the output frequency of matrix converter which may be greater than input frequency, controlling rms value of the output voltage and the ability to control the input displacement factor.At the end of this paper simulation and experimental results are introduced which give a presice proof to the proposed algorithms.</span>
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Tabak, Pero, and Tomislav Kljak. "Traffic Flows Model of Postal Items Based on Input-output Demands in the Public Postal Network: Case Study of Croatia." PROMET - Traffic&Transportation 21, no. 6 (2012): 395–402. http://dx.doi.org/10.7307/ptt.v21i6.256.
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This paper presents the method for developing matrix model of postal traffic flows (ordinary communication items) in public postal network according to volume and different end-to-end (E2E) processes, which can be used for selecting of relevant model for accessing the public postal network. The presented traffic matrix model can be adjusted after the measurement of real volumes and selecting the numbers of different E2E processes (according to geographical input-output request). During the simulation of the model it could be possible to detect the optimal solution for accessing the public postal network. KEY WORDS: traffic modelling, postal services, access to the public postal network
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Moati, Yahia, and Katia Kouzi. "Investigating the Performances of Direct Torque and Flux Control for Dual Stator Induction Motor with Direct and Indirect Matrix Converter." Periodica Polytechnica Electrical Engineering and Computer Science 64, no. 1 (2019): 97–105. http://dx.doi.org/10.3311/ppee.14977.
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This work investigates the performances of Direct Torque Control (DTC) of Dual Stator Induction Motor (DSIM) powered by two types of Matrix Converter (MC), namely the direct and indirect MC. To this end, the design of DTC with conventional Direct Matrix Converter (DMC) is firstly presented. Then, in order to illustrate the main feature of Indirect Matrix Converter (IMC) in terms of the output voltages and input currents waveforms, the full steps of IMC are well explained. To discuss the performance of each scheme, both techniques are simulated in the Matlab / Simulink environment for a 4.5 kW DSIM at different operating conditions. The obtained results show that the IMC provides high performance in torque and flux at different conditions and while minimization the Total Harmonic Distortion (THD) in the input current compared by the conventional DMC.
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Li, Bao Zhu. "The Measurement of Technology Innovation Spillover Effect between Sections: A Case Study of Tangshan." Applied Mechanics and Materials 590 (June 2014): 851–55. http://dx.doi.org/10.4028/www.scientific.net/amm.590.851.
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In this paper, we focused on the measurement and demonstration of technology innovation spillovers effects between sections. The forward R&D flux coefficient matrix model and backward R&D flux coefficient matrix model are established based on the input-output model, and then the beneficiary’s effects and contributor’s effects of ten leading industries within the Tangshan City are calculated. In the end, we found that the oil and natural gas industry got the highest score. The result can be used to make better suggestions for management of Tangshan regional innovation system.
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Sridhar, Srinath, and Rajeswari Sellamani. "Investigation of input variables on temperature rise while end milling Al/SiC metal matrix composite." World Journal of Engineering 17, no. 4 (2020): 599–607. http://dx.doi.org/10.1108/wje-01-2020-0031.
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Purpose The purpose of this paper is to find out the optimal level as well as the influence of end mill cutter geometrical and machining parameters while machining metal matrix composite. End milling is carried out on Al 356/SiC metal matrix composites (MMC) using high-speed steel (HSS) end mill cutter. The optimum level of input parameters such as helix angle, nose radius, rake angle, cutting speed, feed rate and depth of cut are calculated for minimum temperature rise. Design/methodology/approach L27 Taguchi orthogonal design, signal-to-noise (S/N) ratio, are applied for conducting experiments, and to find the optimal level of input parameters for minimum temperature rise, respectively. Analysis of variance (ANOVA) is used to analyze the significance of input parameters on temperature rise. Findings It is found that the optimal combination of helix angle 400, nose radius 0.8 mm, rake angle 80, cutting speed 30 m/min, feed rate 0.04 mm/rev and depth of cut 0.5 mm have generated minimum temperature rise. From ANOVA analysis, it is found that rake angle influence is more on output performance followed by cutting speed and nose radius compared with other machining and geometrical parameters. Originality/value The influence of geometrical parameters such as helix angle, nose radius and rake angle of end mill cutter on temperature rise while machining MMC has not been explored previously.
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Saad, D. "TRAINING RECURRENT NEURAL NETWORKS — THE MINIMAL TRAJECTORY ALGORITHM." International Journal of Neural Systems 03, no. 01 (1992): 83–101. http://dx.doi.org/10.1142/s0129065792000097.
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The Minimal Trajectory (MINT) algorithm for training recurrent neural networks with a stable end point is based on an algorithmic search for the systems’ representations in the neighbourhood of the minimal trajectory connecting the input-output representations. The said representations appear to be the most probable set for solving the global perceptron problem related to the common weight matrix, connecting all representations of successive time steps in a recurrent discrete neural networks. The search for a proper set of system representations is aided by representation modification rules similar to those presented in our former paper,1 aimed to support contributing hidden and non-end-point representations while supressing non-contributing ones. Similar representation modification rules were used in other training methods for feed-forward networks,2–4 based on modification of the internal representations. A feed-forward version of the MINT algorithm will be presented in another paper.5 Once a proper set of system representations is chosen, the weight matrix is then modified accordingly, via the Perceptron Learning Rule (PLR) to obtain the proper input-output relation. Computer simulations carried out for the restricted cases of parity and teacher-net problems show rapid convergence of the algorithm in comparison with other existing algorithms, together with modest memory requirements.
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Yang, Tiantan, Pingchun Wang, and Feng Li. "Centralized Resource Allocation and Target Setting Based on Data Envelopment Analysis Model." Mathematical Problems in Engineering 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/3826096.
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This paper aims to develop a data envelopment analysis (DEA) based model for allocating input resources and deciding output targets in organizations with a centralized decision-making environment, for example, banks, police stations, and supermarket chains. The central decision-maker has an interest in maximizing the total output production and at the same time minimizing the total input consumption. Traditionally, all decision-making units (DMUs) can be easily projected to the efficient frontier, which is a mathematical feasibility; however, it does not guarantee the managerial feasibility during the planning period. In this paper, we will take potential limitations of input-output changes into account by building a difficulty coefficient matrix of modifying their production in the current production possibility set so that the solution guarantees managerial feasibilities. Three objectives, namely, maximizing aggregated outputs, minimizing the consumption of input resources, and minimizing the total difficulty coefficient, are proposed and incorporated into the formation of resource allocation and target setting scheme. Building on this, we combine DEA and multiobjective programming to solve the resource allocation and target setting problem. In the end, we apply our proposed approach to a real-world problem of sixteen chain hotels to illustrate the efficacy and usefulness of the proposed approach.
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S., Rajeswari, and Sivasakthivel P.S. "Optimisation of milling parameters with multi-performance characteristic on Al/SiC metal matrix composite using grey-fuzzy logic algorithm." Multidiscipline Modeling in Materials and Structures 14, no. 2 (2018): 284–305. http://dx.doi.org/10.1108/mmms-04-2017-0027.
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Purpose The purpose of this paper is to determine the optimum level of geometrical parameters such as helix angle, nose radius, rake angle and machining parameters such as cutting speed, feed rate and depth of cut to arrive minimum surface roughness and tool wear during end milling of Al 356/SiC metal matrix composites (MMCs) using high speed steel end mill cutter. Design/methodology/approach L27 Taguchi orthogonal design with six factors and three levels is employed for conducting experiments. Analysis of variance (ANOVA) is carried out using Minitab16 software to find the influence of each input parameter on output performance measure. Grey-fuzzy logic multi optimisation algorithm is used to find the optimum level of the input parameters for minimum surface roughness and tool wear simultaneously. Findings It is found that optimal combination of helix angle 40°, nose radius 0.8 mm, rake angle 12°, cutting speed 90 m/min, feed rate 0.04 mm/rev and depth of cut 1.5 mm have generated minimum surface roughness of 0.4063 µm and tool wear of 0.0375 mm. From ANOVA analysis, it is found that cutting speed influence is more on output performance followed by helix angle and rake angle compared with other machining and geometrical parameters. Originality/value The influence of tool geometry during end milling of MMC using Grey-fuzzy logic algorithm has not been explored previously.
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Voevoda, Alexander, and Vladislav Filiushov. "Polynomial matrix decomposition for the synthesis of non-square control systems." Analysis and data processing systems, no. 1 (March 26, 2021): 21–38. http://dx.doi.org/10.17212/2782-2001-2021-1-21-38.
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The application of advanced synthesis methods is due to the increasing complexity of control objects. Relatively simple objects are represented as a single-channel system or as a combination of such systems and are calculated separately. More complex systems must be viewed as multi-input and multi-output systems. There are several approaches to this. Within the framework of this paper we will consider the synthesis of a system presented in the form of a polynomial matrix decomposition. It allows us to write a closed loop system in such a way that, by analogy with single-channel systems, it is possible to single out the "numerator" and "denominator" not only of the object and the controller, but of the entire system. For multichannel objects, they will be written in a matrix form allowing you to select the characteristic matrix whose determinant is the characteristic polynomial. In this paper, an emphasis is placed on the derivation of four variants of the polynomial matrix description (PMD) of a closed system. Such a variety of representation of a closed-loop system follows from the equivalent writing of the transfer matrix in the form of left and right PMD of an object or controller. Of the four options for recording the system, two options – left and right – for the characteristic matrix are distinguished. When they are reduced to a diagonal form, the elements on the main diagonal contain the poles of a closed system along the corresponding channel. From the example given at the end of the paper, it can be seen that it is more convenient to use the left characteristic matrix because it has a lower dimension for a non-square object (the number of input and output quantities is not equal), with the number of input actions exceeding the number of output quantities, The right characteristic matrix can also be used to synthesize such a control object, but the resulting solution is more complicated and not obvious. The situation is reversed if we consider an object with fewer inputs than outputs. In this case, the right characteristic matrix will be smaller and more suitable for synthesis. It follows from this that the procedure for synthesizing a control system for non-square objects differs depending on the number of inputs and outputs.
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KULYK, Volodymyr. "Critical infrastructure in the system of production and financial and economic relations "input-output"." Fìnansi Ukraïni 2021, no. 6 (2021): 89–108. http://dx.doi.org/10.33763/finukr2021.06.089.
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The production process in the system of economic cycle of the national economy, as well as the relevant tools for the study of production processes, is considered. The production infrastructure of the national economy is studied as an important part of critical infrastructure, reproduction processes. Production is considered in the context of the formation of added value by large groups of types of economic activity, at the institutional and regional levels, in the context of making management decisions at the macro- and microeconomic levels. The inter-industry balance sheet tools are defined as the basic one for assessing production processes and their criticality. To this end, aggregated three-sector input-output tables in producer’s prices for a number of countries have been prepared. Within their framework, the sectoral structure of the economy is considered, direct costs and full costs (Leontief matrix) are determined, indicators of criticality of the production infrastructure are determined. It is proposed to assess the criticality of production infrastructure using such parameters as the share of gross added value in output, the cost of sectors and the economy as a whole, the coefficients of impact and recall, the classification of industries into key, with direct and inverse impact, etc. Comparative studies of criticality indicators for a number of countries were carried out, in particular, direct costs and derivative indicators of criticality of the production system (Frobenius number, Frobenius vector, etc.) were determined. The proposed approaches to improving the parameters of criticality of the production infrastructure of the Ukrainian economy were worked out.
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Sellah, Mourad, Abdellah Kouzou, Mostefa Mohamed-Seghir, Mohamed Mounir Rezaoui, Ralph Kennel, and Mohamed Abdelrahem. "Improved DTC-SVM Based on Input-Output Feedback Linearization Technique Applied on DOEWIM Powered by Two Dual Indirect Matrix Converters." Energies 14, no. 18 (2021): 5625. http://dx.doi.org/10.3390/en14185625.
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This paper focuses on the application of the direct torque control based on space vector modulation (DTC-SVM), combined with the input–output feedback linearization (IOFL) technique on a three-phase dual open-end windings induction motor (DOEWIM) fed by two dual indirect matrix converters. The main aim of integrating the non-linear technique is to overcome the main drawbacks met within the application of the conventional DTC-SVM on dual-stator induction motor (DSIM), such as the torque and flux ripples reduction, the stator harmonics current minimization, and the elimination of the common-mode voltage (CMV). Furthermore, it is proved in this paper that the proposed control on DOEWIN can ensure more flexibility versus speed reverse and variation, load torque changes, and motor parameters variation. The obtained results prove the validity of the proposed control on the studied induction motor topology in ensuring the main aforementioned advantages compared to the conventional DTC-SVM control on DSIM, which presents a promising solution, especially in industrial applications in which high-power motors are required.
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Gkonis, P., D. Kaklamani, I. Venieris, et al. "On the Reduction of Transmission Complexity in MIMO-WCDMA Frequency-Selective Fading Orientations via Eigenvalue Analysis." Electronics 7, no. 10 (2018): 239. http://dx.doi.org/10.3390/electronics7100239.
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In this paper, a novel transmission strategy for Mutliple Input Multiple Output Wideband Code Division Multiple Access (MIMO-WCDMA) orientations operating in frequency-selective fading environments is investigated, in terms of overall algorithmic complexity reduction. To this end, Principal Component Analysis (PCA) is employed on the received data matrix, in order to define the significant terms that are taken into account during transmission matrix formulation. According to the presented results, feedback information of only the primary eigenvector of the corresponding covariance matrix of the received data matrix is required, in order to maintain the mean Bit Error Rate (BER) at acceptable levels. In particular, a complexity reduction of up to 10% can be achieved, when comparing BER values derived by the selection of all components of the received covariance matrix during transmission matrix formulation, and the corresponding BER when selecting half of the components. This reduction is maintained to 10%, when considering a realistic four-element antenna design; however, in this case mean BER inaccuracy is further reduced to 1%.
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Rodríguez, José-Víctor, Mats Gustafsson, José-María Molina-García-Pardo, Leandro Juan-Llácer, and Ignacio Rodríguez-Rodríguez. "Frequency-Selective Wallpaper for Indoor Interference Reduction and MIMO Capacity Improvement." Symmetry 12, no. 5 (2020): 695. http://dx.doi.org/10.3390/sym12050695.
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This paper presents the design and features of frequency-selective wallpaper—based on periodic and symmetric metallic hexagons—intended to be attached to standard walls for filtering out 5 GHz signals (e.g., IEEE 802.11a systems) without blocking other selected radio communication services (e.g., cellular mobile communication signals). It analyzes the characteristics of the radio channel—as found within standard indoor environments—with both regular walls and walls with the proposed frequency-selective wallpaper, examined using a ray-launching program for single-input single-output (SISO) and multiple-input multiple-output (MIMO) systems. This allows the harvesting of parameters, including channel capacity, power delay profile, and signal-to-interference ratio, for proper comparison between the two environments under study: with and without the presented wallpaper. The achieved results clearly show that the use of the proposed frequency-selective wallpaper in an indoor scenario reduces interference levels by an additional attenuation of up to 20 dB in comparison to an unpapered wall. Additionally, with MIMO systems, radio channel characteristics, such as capacity, are improved due to the increase in the magnitude of all singular values of the channel transfer matrix compared to the unpapered wall case, thereby leading to the existence of more relevant subchannels.
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Xie, Zhuang, Jiahua Zhu, Chongyi Fan, Xiaotao Huang, and Jian Wang. "Robust Range Ambiguous Deceptive Target Suppression Based on Covariance Matrix Reconstruction." Remote Sensing 13, no. 12 (2021): 2346. http://dx.doi.org/10.3390/rs13122346.
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When the deceptive targets are in the ambiguious range bin but are received at the same range gate with the desired target by the array, the traditional multiple-input multiple-output (MIMO) radar is not able to discriminate between them. Based on the unique range-dependent beampattern of the frequency diverse array (FDA)-MIMO radar, we propose a novel robust mainlobe deceptive target suppression method based on covariance matrix reconstruction to form nulls at the frequency points of the transmit–receive domain where deceptive targets are located. First, the proposed method collects the deceptive targets and noise information in the transmit–receive frequency domain to reconstruct the jammer-noise covariance matrix (JNCM). Then, the covariance matrix of the desired target is constructed in the desired target region, which is assumed to already be known. The transmit–receive steering vector (SV) of the desired target is estimated to be the dominant eigenvector of the desired target covariance matrix. Finally, the weighting vector of the receive beamformer is calculated by combining the reconstructed JNCM and the estimated desired target SV. By implementing the weighting vector at the receiving end, the deceptive targets can be effectively suppressed. The simulation results demonstrate that the proposed method is robust to SV mismatches and provides a signal-to-jamming-plus-noise ratio (SJNR) output that is close to the optimal.
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Gkonis, Panagiotis K., Panagiotis T. Trakadas, and Lambros E. Sarakis. "Non-Orthogonal Multiple Access in Multiuser MIMO Configurations via Code Reuse and Principal Component Analysis." Electronics 9, no. 8 (2020): 1330. http://dx.doi.org/10.3390/electronics9081330.
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The goal of the study presented in this paper is to evaluate the performance of a proposed transmission scheme in multiuser multiple-input multiple-output (MIMO) configurations, via code reuse. Hence, non-orthogonal multiple access (NOMA) is performed. To this end, a correlation matrix of the received data is constructed at the transmitter, with feedback as only the primary eigenvector of the equivalent channel matrix, which is derived after principal component analysis (PCA) at the receiver. Afterwards, users experiencing improved channel quality (i.e., diagonal terms of the correlation matrix) along with reduced multiple access interference (i.e., the inner product of transmission vectors) are the potential candidates for their assigned code to be reused. As the results indicate, considering various MIMO configurations, the proposed approach can achieve almost 33% code assignment gain (CAG), when successive interference cancellation (SIC) is employed in mobile receivers. However, even in the absence of SIC, CAG is still maintained with a tolerable average bit error rate (BER) degradation.
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Potejana, Potejanasak, and Chakthong Thongchattu. "Application of Taguchi and Response Surface Methodologies for Surface Roughness in Rotary Tool Polishing Hardness Mould Steels." Advanced Materials Research 383-390 (November 2011): 882–86. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.882.
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This research proposes a new application of 3-axis CNC milling machine for polishing the 60 HRC hardness steels. The rotary polishing tools are designed by refer to the end-mill ball nose’s design. And the diamond powder was coated in rotary polishing tools. The L12 orthogonal array of the Taguchi’s method is selected to conduct the matrix experiment to determine the optimal polishing process parameters. The result show that polishing time was a dominant parameter for the surface roughness and the next was depth of penetration. The response surface design is then used to build the relationship between the input parameters and output responses. The experimental results show that the integrated approach does indeed find the optimal parameters that result in very good output responses in the rotary polishing tools polished hardness mould steel using CNC milling machine.
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Mihaly, Vlad, Mircea Şuşcă та Petru Dobra. "Krasovskii Passivity and μ-Synthesis Controller Design for Quasi-Linear Affine Systems". Energies 14, № 17 (2021): 5571. http://dx.doi.org/10.3390/en14175571.
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This paper presents an end-to-end method to design passivity-based controllers (PBC) for a class of input-affine nonlinear systems, named quasi-linear affine. The approach is developed using Krasovskii’s method to design a Lyapunov function for studying the asymptotic stability, and a sufficient condition to construct a storage function is given, along with a supply-rate function. The linear fractional transformation interconnection between the nonlinear system and the Krasovskii PBC (K-PBC) results in a system which manages to follow the provided input trajectory. However, given that the input and output of the closed-loop system do not have the same physical significance, a path planning is mandatory. For the path planning component, we propose a robust controller designed using the μ-synthesis mixed-sensitivity loop-shaping for the linearized system around a desired equilibrium point. As a case study, we present the proposed methodology for DC-DC converters in a unified manner, giving sufficient conditions for such systems to be Krasovskii passive in terms of Linear Matrix Inequalities (LMIs), along with the possibility to compute both the K-PBC and robust controller alike.
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Aldieri, Luigi, Maria Carmela Aprile, and Concetto Paolo Vinci. "R&D Spillover Effects on the Strategic Behavior of Large International Firms during the World Financial Crisis." International Journal of Business and Management 12, no. 11 (2017): 141. http://dx.doi.org/10.5539/ijbm.v12n11p141.
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The aim of this study is to investigate the relationship between competition and innovation through the knowledge spillover effect. In particular, we investigate whether R&D competition is sensitive to economic shock. To this end, we consider a period of time related also to the 2008 financial crisis. We implement an empirical analysis of 879 worldwide R&D-intensive firms. In order to measure technological proximity, we use two approaches: one based on Jaffe industry weight matrix, relative to patents distributed across technology classes; one based on trade intensity between sectors using input–output matrix data. The empirical results show a positive effect of R&D externalities on competitive interactions before the beginning of crisis and a negative one after it. These findings are robust with respect to the procedure employed in the estimation method.
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Dai, Baolin, Jun Gong, and Cuiming Li. "Optimal Gains of Iterative Learning Control with Forgetting Factor." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 37, no. 5 (2019): 1077–84. http://dx.doi.org/10.1051/jnwpu/20193751077.
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In order to solve the optimization problems of convergence characteristics of a class of single-input single-output (SISO) discrete linear time-varying systems (LTI) with time-iteration-varying disturbances, an optimal control gain design method of PID type iterative learning control (ILC) algorithm with forgetting factor was presented. The necessary and sufficient condition for the ILC system convergence was obtained based on iterative matrix theory. The convergence of the learning algorithm was proved based on operator theory. According to optimization theory and Toeplitz matrix characteristics, the monotonic convergence condition of the system was established. The accurate solution of the optimal control gain and the relationship equation between the forgetting factor and the optimal control gains were obtained according to the optimal theory which ensures the fastest system convergence speed, thereby reaching the end of the system convergence improvement. The convergence condition is weaker than the known results. The proposed method overcomes the shortcomings of traditional optimal control gain in ILC algorithm with forgetting factor, effectively accelerates the system convergence speed, suppresses the system output track error fluctuation, and provides a better solution for LTI system with time-iteration-varying disturbances. Simulation verifies the effectiveness of the control algorithm.
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Al-Jazzar, Saleh O., and Sami Aldalahmeh. "AOA, Delay, and Complex Propagation Factor Estimation for the Monostatic MIMO Radar System." International Journal of Antennas and Propagation 2018 (November 22, 2018): 1–7. http://dx.doi.org/10.1155/2018/2054271.
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In this paper, we propose a solution to find the angle of arrival (AOA), delay, and the complex propagation factor for the monostatic multiple-input multiple-output (MIMO) radar system. In contrast to conventional iterative computationally demanding estimation schemes, we propose a closed form solution for most of the previous parameters. The solution is based on forming an approximate correlation matrix of the received signals at the MIMO radar receiver end. Then, an eigenvalue decomposition (EVD) is performed on the formed approximate correlation matrix. The AOAs of the received signals are deduced from the corresponding eigenvectors. Then, the delays are estimated from the received signal matrix properties. This is followed by forming structured matrices which will be used to find the complex propagation factors. These estimates can be used as initializations for other MIMO radar methods, such as the maximum likelihood algorithm. Simulation results show significantly low root mean square error (RMSE) for AOAs and complex propagation factors. On the other hand, our proposed method achieves zero RMSE in estimating the delays for relatively low signal-to-noise ratios (SNRs).
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Reddy, Mohan. "Signal Detection in Spatially Multiplexed MIMO Systems." International Journal for Research in Applied Science and Engineering Technology 9, no. VI (2021): 5002–5. http://dx.doi.org/10.22214/ijraset.2021.36053.
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The transmission of several signals and reception of those signals, it requires the implementation of multiple transmitters at the transmitter side and the multiple receivers at the receiver side. This type of system is called multiple input multiple output (M.I.M.O) system. The M.I.M.O systems will result in obtaining the better use of the available spectrum for transmissions of the different signals in the same spectrum and this makes the M.I.M.O systems most dependable for the wireless communications. But the presence of several signals in the same bandwidth of spatial multiplexing matrix in M.I.M.O systems makes it difficult for the signal to get detected at the receiver end. There are plenty of techniques introduced to avoid the difficulty in sensing the signal at receiver in M.I.M.O systems. In this paper we will be discussing about the signal detection technique called minimum mean square error technique (MMSE) which uses the inversion of the matrix to retrieve the signal and the iteration-based method that is an improvised technique than MMSE technique where the matrix inversion step is avoided and provides better results. The results are obtained by plotting the bit error rate versus the signal to nose ratio using MATLAB
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González-Coma, José P., Pedro Suárez-Casal, Paula M. Castro, and Luis Castedo. "FDD Channel Estimation Via Covariance Estimation in Wideband Massive MIMO Systems." Sensors 20, no. 3 (2020): 930. http://dx.doi.org/10.3390/s20030930.
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A method for channel estimation in wideband massive Multiple-Input Multiple-Output systems using hybrid digital analog architectures is developed. The proposed method is useful for Frequency-Division Duplex at either sub-6 GHz or millimeter wave frequency bands and takes into account the beam squint effect caused by the large bandwidth of the signals. To circumvent the estimation of large channel vectors, the posed algorithm relies on the slow time variation of the channel spatial covariance matrix, thus allowing for the utilization of very short training sequences. This is possibledue to the exploitation of the channel structure. After identifying the channel covariance matrix, the channel is estimated on the basis of the recovered information. To that end, we propose a novel method that relies on estimating the tap delays and the gains as sociated with each path. As a consequence, the proposed channel estimator achieves low computational complexity and significantly reduces the training overhead. Moreover, our numerical simulations show better performance results compared to the minimum mean-squared error solution.
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Jiang, Dan, and Jin He. "Text Semantic Classification of Long Discourses Based on Neural Networks with Improved Focal Loss." Computational Intelligence and Neuroscience 2021 (January 7, 2021): 1–9. http://dx.doi.org/10.1155/2021/8845362.
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Semantic classification of Chinese long discourses is an important and challenging task. Discourse text is high-dimensional and sparse. Furthermore, when the number of classes of dataset is large, the data distribution will be seriously imbalanced. In solving these problems, we propose a novel end-to-end model called CRAFL, which is based on the convolutional layer with attention mechanism, recurrent neural networks, and improved focal loss function. First, the residual network (ResNet) extracts phrase semantic representations from word embedding vectors and reduces the dimensionality of the input matrix. Then, the attention mechanism differentiates the focus on the output of ResNet, and the long short-term memory layer learns the features of the sequences. Lastly but most significantly, we apply an improved focal loss function to mitigate the problem of data class imbalance. Our model is compared with other state-of-the-art models on the long discourse dataset, and CRAFL model has proven be more efficient for this task.
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Jiang, Dan, and Jin He. "Text Semantic Classification of Long Discourses Based on Neural Networks with Improved Focal Loss." Computational Intelligence and Neuroscience 2021 (January 7, 2021): 1–9. http://dx.doi.org/10.1155/2021/8845362.
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Semantic classification of Chinese long discourses is an important and challenging task. Discourse text is high-dimensional and sparse. Furthermore, when the number of classes of dataset is large, the data distribution will be seriously imbalanced. In solving these problems, we propose a novel end-to-end model called CRAFL, which is based on the convolutional layer with attention mechanism, recurrent neural networks, and improved focal loss function. First, the residual network (ResNet) extracts phrase semantic representations from word embedding vectors and reduces the dimensionality of the input matrix. Then, the attention mechanism differentiates the focus on the output of ResNet, and the long short-term memory layer learns the features of the sequences. Lastly but most significantly, we apply an improved focal loss function to mitigate the problem of data class imbalance. Our model is compared with other state-of-the-art models on the long discourse dataset, and CRAFL model has proven be more efficient for this task.
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Kim, SungHwan, Jae-Hwan Jhong, JungJun Lee, Ja-Yong Koo, ByungYong Lee, and SungWon Han. "Node-Structured Integrative Gaussian Graphical Model Guided by Pathway Information." Computational and Mathematical Methods in Medicine 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/8520480.
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Up to date, many biological pathways related to cancer have been extensively applied thanks to outputs of burgeoning biomedical research. This leads to a new technical challenge of exploring and validating biological pathways that can characterize transcriptomic mechanisms across different disease subtypes. In pursuit of accommodating multiple studies, the joint Gaussian graphical model was previously proposed to incorporate nonzero edge effects. However, this model is inevitably dependent on post hoc analysis in order to confirm biological significance. To circumvent this drawback, we attempt not only to combine transcriptomic data but also to embed pathway information, well-ascertained biological evidence as such, into the model. To this end, we propose a novel statistical framework for fitting joint Gaussian graphical model simultaneously with informative pathways consistently expressed across multiple studies. In theory, structured nodes can be prespecified with multiple genes. The optimization rule employs the structured input-output lasso model, in order to estimate a sparse precision matrix constructed by simultaneous effects of multiple studies and structured nodes. With an application to breast cancer data sets, we found that the proposed model is superior in efficiently capturing structures of biological evidence (e.g., pathways). An R software package nsiGGM is publicly available at author’s webpage.
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Jiao, Chenlei, Zhe Wang, Bingrui Lv, Guilian Wang, and Weiliang Yue. "Design and Analysis of a Novel Flexure-Based XY Micropositioning Stage." Applied Sciences 10, no. 23 (2020): 8336. http://dx.doi.org/10.3390/app10238336.
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Flexure-based micropositioning stages with high positioning precision are really attractive. This paper reports the design and analysis processes of a two-degree-of-freedom (2-DOF) flexure-based XY micropositioning stage driven by piezoelectric actuators to improve the positioning accuracy and motion performance. First, the structure of the stage was proposed, which was based on rectangular flexure hinges and piezoelectric actuators (PZT) that were arranged symmetrically to realize XY motion. Then, analytical models describing the output stiffness in the XY directions of the stage were established using the compliance matrix method. The finite element analysis method (FEA) was used to validate the analytical models and analyze the static characteristics and the natural frequency of the stage simultaneously. Furthermore, a prototype of the micropositioning stage was fabricated for the performance tests. The output response performance of the stage without an end load was tested using different input signals. The results indicated that the stage had a single direction amplification capability, low hysteresis, and a wide positioning space. The conclusion was that the proposed stage possessed an ideal positioning property and could be well applied to the positioning system.
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Chen, Zhong Jie, Qui Ju Zhang, and Chun Jian Hua. "Study on Delta Parallel Mechanism Kinematics and Singularity Based on Inverse Solution." Applied Mechanics and Materials 43 (December 2010): 114–18. http://dx.doi.org/10.4028/www.scientific.net/amm.43.114.
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In this paper, the kinematic analysis on a 3-DOF Delta parallel mechanism was carried out and the relationship models between the end cell output motions and the master arms input parameters were established. The forward and inverse solutions to position, velocity and acceleration were deduced and then verified by simulation, the curves that gotten by calculation and simulation were smooth, and no mutations or jumps appeared. In the meantime, based on the kinematic analysis, the impact of Jacobian matrix on the manipulator singular configuration was discussed, and the maneuverability in the reachable space was obtain quantitatively, meanwhile, the value of cond(C(Jv)) was located in the acceptable range, which approached to the isotropic value, so, the theory basis for optimal design was provided. The methods and conclusions in this paper are helpful to the design and control of 3-DOF Delta parallel mechanism.
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Zhang, Yule, Guoping Hu, Hao Zhou, Mingming Zhu, and Fei Zhang. "DOA Estimation of a Novel Generalized Nested MIMO Radar with High Degrees of Freedom and Hole-Free Difference Coarray." Mathematical Problems in Engineering 2021 (January 27, 2021): 1–9. http://dx.doi.org/10.1155/2021/6622154.
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A novel generalized nested multiple-input multiple-output (MIMO) radar for direction of arrival (DOA) estimation is proposed in this paper. The proposed structure utilizes the extended two-level nested array (ENA) as transmitter and receiver and adjusts the interelement spacing of the receiver with an expanding factor. By optimizing the array element configuration, we can obtain the best number of elements of the transmitter and receiver and the attainable degrees of freedom (DOF). Compared with the existing nested MIMO radar, the proposed MIMO array configuration not only has closed-form expressions for sensors’ positions and the number of maximum DOF, but also significantly improves the array aperture. It is verified that the sum-difference coarray (SDCA) of the proposed nested MIMO radar can get higher DOF without holes. MUSIC algorithm based on Toeplitz matrix reconstruction is employed to prove the rationality and superiority of the proposed MIMO structure.
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Assal, Samy F. M. "Self-organizing approach for learning the forward kinematic multiple solutions of parallel manipulators." Robotica 30, no. 6 (2011): 951–61. http://dx.doi.org/10.1017/s0263574711001172.
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SUMMARYContrary to the inverse kinematics, the forward kinematics of parallel manipulators involves solving highly non-linear equations and provides more than one feasible end-effector pose, which are called the assembly modes, for a given set of link lengths or joint angles. Out of the multiple feasible solutions, only one solution can be achieved from a certain initial configuration. Therefore, in this paper, the Kohonen's self-organizing map (SOM) is proposed to learn and classify the multiple solution branches of the forward kinematics and then provide a unique real-time solution among the assembly modes. Each solution of the multiple feasible ones is coded using IF-THEN rules based on the values of the passive joint variables. Due to not only the classification but also the associative memory learning abilities of the SOM, the passive joint variables vector, the end-effector pose vector, and this class code are associated with the active joint variables vector constituting the input vector to the SOM in the offline learning phase. In the online testing phase, only the active joint variables vector and the class code are fed to the SOM to obtain the unique end-effector pose vector. The Jacobian matrix calculated at the SOM output layer is used for further fine tuning this output to obtain an accurate end-effector pose vector. Simulations are conducted for 3-RPR and 3-RRR planar parallel manipulators to evaluate the performance of the proposed method. The results proved high accuracy of the desired unique solution in real-time.
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Shubov, Marianna A., and Laszlo P. Kindrat. "Asymptotics of the eigenmodes and stability of an elastic structure with general feedback matrix." IMA Journal of Applied Mathematics 84, no. 5 (2019): 873–911. http://dx.doi.org/10.1093/imamat/hxz019.
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Abstract The distribution of natural frequencies of the Euler–Bernoulli beam subject to fully non-dissipative boundary conditions is investigated. The beam is clamped at the left end and equipped with a 4-parameter ($\alpha ,\beta ,k_1,k_2$) linear boundary feedback law at the right end. The $2 \times 2$ boundary feedback matrix relates the control input (a vector of velocity and its spatial derivative at the right end), to the output (a vector of shear and moment at the right end). The initial boundary value problem describing the dynamics of the beam has been reduced to the first order in time evolution equation in the state Hilbert space equipped with the energy norm. The dynamics generator has a purely discrete spectrum (the vibrational modes) denoted by $\{\nu _n\}_{n\in \mathbb {Z}^{\prime}}$. The role of the control parameters is examined and the following results have been proven: (i) when $\beta \neq 0$, the set of vibrational modes is asymptotically close to the vertical line on the complex $\nu$-plane given by the equation $\Re \nu = \alpha + (1-k_1k_2)/\beta$; (ii) when $\beta = 0$ and the parameter $K = (1-k_1 k_2)/(k_1+k_2)$ is such that $\left |K\right |\neq 1$ then the following relations are valid: $\Re (\nu _n/n) = O\left (1\right )$ and $\Im (\nu _n/n^2) = O\left (1\right )$ as $\left |n\right |\to \infty$; (iii) when $\beta =0$, $|K| = 1$, and $\alpha = 0$, then the following relations are valid: $\Re (\nu _n/n^2) = O\left (1\right )$ and $\Im (\nu _n/n) = O\left (1\right )$ as $\left |n\right |\to \infty$; (iv) when $\beta =0$, $|K| = 1$, and $\alpha>0$, then the following relations are valid: $\Re (\nu _n/\ln \left |n\right |) = O\left (1\right )$ and $\Im (\nu _n/n^2) = O\left (1\right )$ as $\left |n\right |\to \infty$.
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Fan, Peng. "Application of deep learning and cloud data platform in college teaching quality evaluation." Journal of Intelligent & Fuzzy Systems 39, no. 4 (2020): 5547–58. http://dx.doi.org/10.3233/jifs-189036.
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In this paper, the author introduces the theory of fuzzy mathematics into the evaluation of higher education. By determining the set of evaluation factors and comments, the author constructs the relevant mathematical model and processes the data, thus turning the evaluation problem into the multiplication problem of the fuzzy matrix. Deep learning is a very active branch of machine learning research in recent years. By increasing the depth and breadth of the model, i.e. increasing the number of operations from the input end to the output end and the number of channels of the model, the scale of parameters of the model is increased, so that the model has the ability to express complex functions. It is appropriate to use deep learning in teaching quality evaluation. The simulation results show that the deep learning model is very effective in dealing with data diversity and extracting complex implicit rules. It can effectively model experts’ professional knowledge and experience. Deep neural network has powerful expressive ability, and can effectively extract the deep-seated laws affecting the teaching quality. It can be used as an assistant technology for the evaluation of teaching quality in Colleges.
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Reinoso Chisaguano, Diego Javier, and Minoru Okada. "Low Complexity Submatrix Divided MMSE Sparse-SQRD Detection for MIMO-OFDM with ESPAR Antenna Receiver." VLSI Design 2013 (April 30, 2013): 1–11. http://dx.doi.org/10.1155/2013/206909.
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Multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) with an electronically steerable passive array radiator (ESPAR) antenna receiver can improve the bit error rate performance and obtains additional diversity gain without increasing the number of Radio Frequency (RF) front-end circuits. However, due to the large size of the channel matrix, the computational cost required for the detection process using Vertical-Bell Laboratories Layered Space-Time (V-BLAST) detection is too high to be implemented. Using the minimum mean square error sparse-sorted QR decomposition (MMSE sparse-SQRD) algorithm for the detection process the average computational cost can be considerably reduced but is still higher compared with a conventional MIMOOFDM system without ESPAR antenna receiver. In this paper, we propose to use a low complexity submatrix divided MMSE sparse-SQRD algorithm for the detection process of MIMOOFDM with ESPAR antenna receiver. The computational cost analysis and simulation results show that on average the proposed scheme can further reduce the computational cost and achieve a complexity comparable to the conventional MIMO-OFDM detection schemes.
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Barthels, Henrik, Christos Psarras, and Paolo Bientinesi. "Linnea." ACM Transactions on Mathematical Software 47, no. 3 (2021): 1–26. http://dx.doi.org/10.1145/3446632.
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The translation of linear algebra computations into efficient sequences of library calls is a non-trivial task that requires expertise in both linear algebra and high-performance computing. Almost all high-level languages and libraries for matrix computations (e.g., Matlab, Eigen) internally use optimized kernels such as those provided by BLAS and LAPACK; however, their translation algorithms are often too simplistic and thus lead to a suboptimal use of said kernels, resulting in significant performance losses. To combine the productivity offered by high-level languages, and the performance of low-level kernels, we are developing Linnea, a code generator for linear algebra problems. As input, Linnea takes a high-level description of a linear algebra problem; as output, it returns an efficient sequence of calls to high-performance kernels. Linnea uses a custom best-first search algorithm to find a first solution in less than a second, and increasingly better solutions when given more time. In 125 test problems, the code generated by Linnea almost always outperforms Matlab, Julia, Eigen, and Armadillo, with speedups up to and exceeding 10×.
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Rabe, H., D. Kornek, M. Stege, and I. Rolfes. "MIMO performance of a planar logarithmically periodic antenna with respect to measured channel matrices." Advances in Radio Science 6 (May 26, 2008): 55–61. http://dx.doi.org/10.5194/ars-6-55-2008.
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Abstract. The increasing interest in wireless transmission of highest data rates for multimedia applications (e.g. HDTV) demands the use of communication systems as e.g. described in the IEEE 802.11n draft specification for WLAN including spatial multiplexing or transmit diversity to achieve a constant high data rate and a small outage probability. In a wireless communications system the transmission of parallel data stream leads to multiple input/multiple output (MIMO) systems, whose key parameters heavily depend on the properties of the mobile channel. Assuming an uncorrelated channel matrix the correlation between the multiplexed data streams is caused by the coupling of the antennas, so that the radiation element becomes an even more important part of the system. Previous work in this research area (Klemp and Eul, 2006) has shown that planar log.-per four arm antennas are promising candidates for MIMO applications providing two nearly decorrelated radiators, which cover a wide frequency range including both WLAN bands at 2.4 GHz and 5.4 GHz. Up to now the MIMO performance of this antenna is mainly analyzed by simulations. In this contribution measured channel matrices in a real office environment are studied in terms of the antenna's MIMO performance such as outage probability. The obtained results recorded by using a commercial platform are compared to the simulated ones.
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Szymanski, T. H., and D. Gilbert. "Design of an IPTV Multicast System for Internet Backbone Networks." International Journal of Digital Multimedia Broadcasting 2010 (2010): 1–14. http://dx.doi.org/10.1155/2010/169140.
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The design of an IPTV multicast system for the Internet backbone network is presented and explored through extensive simulations. In the proposed system, a resource reservation algorithm such as RSVP, IntServ, or DiffServ is used to reserve resources (i.e., bandwidth and buffer space) in each router in an IP multicast tree. Each router uses an Input-Queued, Output-Queued, or Crosspoint-Queued switch architecture with unity speedup. A recently proposedRecursive Fair Stochastic Matrix Decompositionalgorithm used to compute near-perfect transmission schedules for each IP router. The IPTV traffic is shaped at the sources usingApplication-Specific Token Bucker Traffic Shapers, to limit the burstiness of incoming network traffic. The IPTV traffic is shaped at the destinations usingApplication-Specific Playback Queues, to remove residual network jitter and reconstruct the original bursty IPTV video streams at each destination. All IPTV traffic flows are regenerated at the destinations with essentially zero delay jitter and essentially-perfect QoS. The destination nodes deliver the IPTV streams to the ultimate end users using the same IPTV multicast system over a regional Metropolitan Area Network. It is shown that all IPTV traffic is delivered with essentially-perfect end-to-end QoS, with deterministic bounds on the maximum delay and jitter on each video frame. Detailed simulations of an IPTV distribution system, multicasting several hundred high-definition IPTV video streams over several essentially saturated IP backbone networks are presented.
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Zhang, Xingjun, Cuiping Jing, Feilong Tang, Scott Fowler, Huali Cui, and Xiaoshe Dong. "Joint Redundant and Random Network Coding for Robust Video Transmission over Lossy Networks." Mobile Information Systems 8, no. 3 (2012): 213–30. http://dx.doi.org/10.1155/2012/931965.
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In this paper a novel unequal packet loss protection scheme R2NC based on low-triangular global coding matrix with ladder-shaped partition is presented, which combines redundant and random network coding for robust H.264/SVC video transmission. Firstly, the error-correcting capabilities of redundant network coding make our scheme resilient to loss. Secondly, the implementation of random network coding at the intermediate nodes with multiple input links can reduce the cost of network bandwidth, thus reducing the end-to-end delay for video transmission. Thirdly, the low-triangular global coding matrix with ladder-shaped partition is maintained throughout the R2NC processes to reduce the impact of global coding matrix's rank deficiency on video transmission and provide unequal erasure protection for H.264/SVC priority layers. The redundant network coding avoids the retransmission of lost packets and improves error-correcting capabilities of lost packets. Based only on the knowledge of the packet loss rates on the output links, the source node and intermediate nodes can make decisions for redundant network coding and random network coding (i.e., how much redundancy to add at this node). However, the redundancy caused by redundant network coding makes the network load increases. In order to improve network throughput, we performed random network coding at the intermediate nodes. Our approach is grounded on the overall distortion of reconstructed video minimization by optimizing the amount of redundancy assigned to each layer. The convex optimization model is constructed under the constraint of network coding and scalable video coding. Experimental results are shown to demonstrate the significant improvement of H.264/SVC video reconstruction quality with R2NC over packet lossy networks.
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Lu, Wei, Yuxi Li, Yicai Ji, Chuanjun Tang, Bin Zhou, and Guangyou Fang. "Ultra-Wideband MIMO Array for Penetrating Lunar Regolith Structures on the Chang’e-5 Lander." Electronics 10, no. 1 (2020): 8. http://dx.doi.org/10.3390/electronics10010008.
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The Chang’e-5 lunar exploration mission of China is equipped with a Lunar Regolith Penetrating Radar (LRPR) for measuring the thickness and structures of the lunar regolith in the landing area. Since the LRPR is stationary, an ultra-wideband multiple-input multiple-output (MIMO) array is designed as a replacement for conventional mobile subsurface probing systems. The MIMO array, with 12 antenna elements and a switch matrix, operates in the frequency band from 1.0 to 4.75 GHz. In this work, the design and layout of the antenna elements were optimized with respect to the lander. To this end, the antenna elements were designed as miniaturized Vivaldi antennas with quarter elliptical slots (i.e., quarter elliptical slotted antenna, or QESA). QESAs are significantly small while being able to mitigate the impact of the lander on antenna electrical performances. QESAs also have a wide operating bandwidth, flat gain, and excellent time domain characteristics. In addition, a high-temperature resistant ultra-light radome with high transmissivity is designed to protect the external antenna array. After calibration, the MIMO array is used to detect targets embedded in volcanic ash. The detection depth reaches 2.5 m, and the detection effect is good.
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Matovic, Valentina, Jasna Trbojevic-Stankovic, Branislava Jeftic, and Lidija Matija. "Glucose concentration monitoring using near infrared spectrum of spent dialysis fluid in hemodialysis patients." Srpski arhiv za celokupno lekarstvo, no. 00 (2020): 90. http://dx.doi.org/10.2298/sarh200215090m.
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Introduction/Objective. Diabetic nephropathy leading to end-stage renal disease is a major health problem worldwide. Hemodialysis treatment is associated with glycemia variations. Diabetic patients on hemodialysis might benefit from a noninvasive online glycemia monitoring system. The aim of this study was to assess the glucose concentration from the matrix of the spent dialysate fluid using Near infrared (NIR) Spectroscopy. Methods. Blood samples and spent dialysate have been collected in the 15th minute of the hemodialysis treatment from 15 patients. The spent dialysis fluid has been characterized by a NIR spectrometer in the range of 900-1300 nm. In order to apply the artificial neural network (ANN) and train it, the MATLNFTOOL program was used. The testing and training of the ANN were executed using the NIR spectrum of the spent dialysis fluid as input, and the glucose concentration as output. Results. A significant correlation in excess of 93% between the NIR spectrum of the spent dialysate and the blood glucose concentration (3-9 mmol/l) has been found. Conclusions. NIR spectroscopy is a noninvasive and reliable method of glycemia monitoring which can be used in maintenance hemodialysis patients.
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Gong, Jinliang, Xiaoming Wang, Fengan Huang, and Yanfei Zhang. "Dynamic performances analysis of hybrid press based on dependent generalized coordinates." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 229, no. 12 (2014): 2187–94. http://dx.doi.org/10.1177/0954406214557342.
Full textAbstract:
A kind of multi-link hybrid press mechanism is brought forth. It adopts three motors as actuations to fulfill the single degree of freedom output of end effector. For hybrid press mechanism, the forward kinematics is usually complicated and its numerical solution is computation-intensive and time-consuming. Therefore, the dynamic model is difficult to build up when it needs to analyze the input function’s effect on system dynamic performances. Concept of dependent generalized coordinates is adpoted here and a kind of dynamic modeling method of multi-link hybrid mechanism is presented based on the virtual work principle. The linear and angular displacements of every component can be expressed concisely in the form of dependent generalized coordinates. They are much simpler than that of independent generalized coordinates. Accordingly, linear and angular velocities will be derived by differentiating with respect to displacements. Velocity Jacobian matrix will be simplified under dependent generalized coordinates system and the virtual work principle-based dynamic model will also be simplified accordingly. Then it needs to introduce constraint conditions and multiplier in order to acquire actuation forces. Introduction of the constraints guarantees the real kinetic characteristics of mechanism. In the end, the curves of actuation forces and spherical joints’ inner forces variations are presented using Matlab. By comparing with Adams simulation results, validity of the method has been proved.
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Kovacevic, Djordje, Mladen Stanojevic, Vladimir Marinkovic, and Miroslav Popovic. "A solution for automatic parallelization of sequential assembly code." Serbian Journal of Electrical Engineering 10, no. 1 (2013): 91–101. http://dx.doi.org/10.2298/sjee1301091k.
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Since modern multicore processors can execute existing sequential programs only on a single core, there is a strong need for automatic parallelization of program code. Relying on existing algorithms, this paper describes one new software solution tool for parallelization of sequential assembly code. The main goal of this paper is to develop the parallelizator which reads sequential assembler code and at the output provides parallelized code for MIPS processor with multiple cores. The idea is the following: the parser translates assembler input file to program objects suitable for further processing. After that the static single assignment is done. Based on the data flow graph, the parallelization algorithm separates instructions on different cores. Once sequential code is parallelized by the parallelization algorithm, registers are allocated with the algorithm for linear allocation, and the result at the end of the program is distributed assembler code on each of the cores. In the paper we evaluate the speedup of the matrix multiplication example, which was processed by the parallelizator of assembly code. The result is almost linear speedup of code execution, which increases with the number of cores. The speed up on the two cores is 1.99, while on 16 cores the speed up is 13.88.
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McPhee, M. J., B. J. Walmsley, D. G. Mayer, and V. H. Oddy. "BeefSpecs fat calculator to assist decision making to increase compliance rates with beef carcass specifications: evaluation of inputs and outputs." Animal Production Science 54, no. 12 (2014): 2011. http://dx.doi.org/10.1071/an14614.
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This study evaluated the BeefSpecs fat calculator, a decision-support system developed to assist the beef industry to increase compliance rates with carcass specifications (weight and fat specifications). A challenge to the BeefSpecs calculator and a sensitivity analysis were used to evaluate the inputs and outputs of BeefSpecs. Five industry datasets (n = 80, 97, 68, 25, and 13 for Datasets 1–5, respectively) of Bos taurus, Bos indicus, and Bos taurus × Bos indicus breeds for steers and heifers were collated to challenge BeefSpecs, and a nine-way factorial matrix (n = 57 600) of input variables was created for the sensitivity analysis. There were no significant (P > 0.05) differences in the mean bias between observed and predicted values in any of the datasets but there were significant (P < 0.01) differences in the unity of slope for Datasets 2, 3, and 5. The root-mean-square error was 1.72, 2.61, 2.87, 2.68, and 2.00 mm for Datasets 1–5. The decomposition of the mean-square error of prediction indicated that most of the error contained in the predictions of all models was of a random nature (94%, 85%, 85%, 95% for Datasets 1–4), except in Dataset 5, which had a 47% proportion of error in the slope component. All datasets indicated little bias (0.13%, 12.19%, 12.69%, 0.60%, and 0.12% for Datasets 1–5) in the model predictions. An analysis of variance with the nine-way factorial matrix on the predicted output of final P8 fat was conducted for the sensitivity analysis. A significant (P < 0.01) four-way interaction of days on feed × frame score × initial liveweight × sex was detected. Final P8 fat was sensitive to measurement error in the inputs of frame score when animals had longer feeding periods (e.g. 180 days) and to initial P8 fat when animals had lower initial liveweights (e.g. 200 kg) and higher frame scores (e.g. 7). For each unit of error in estimating frame score, BeefSpecs predicts final P8 with an error of up to 2.3 mm in heifers and up to 1.7 mm in steers. Error in the estimation of initial P8 fat of 2 mm will result in an error of up to 3 mm in the prediction of final P8 fat. The sensitivity analysis of BeefSpecs input variables (frame score and initial P8 fat) on the prediction of final P8 fat indicates that increasing the accuracy of estimating frame score and P8 fat is an issue that needs addressing.
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CHEN, YUH-WEN. "A GROUP GAME OF MULTIPLE ATTRIBUTE DECISION MAKING." Asia-Pacific Journal of Operational Research 24, no. 05 (2007): 631–45. http://dx.doi.org/10.1142/s0217595907001425.
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Multiple Attribute Decision Making (MADM) problem is a management science technique, which is popularly used to rank the priority of alternatives with respect to their competing attributes. It is popularly used in diverse fields such as engineering management, portfolio selection, transportation planning, and performance evaluation. Weights form the core of MADM: it is obvious that different weights lead to various evaluation results and decisions. Several approaches have been developed for assessing the weights of MADM problems, e.g., the eigenvector method, ELECTRE, and TOPSIS. However, an assessment approach of weights in MADM, which meets both the need of simplicity interface for practitioners and concrete theory for scholars is not easy, and balancing these two aspects is a challenging and tough task. Since the pay-off matrix in game theory could be regarded as a simple interface for data input/output, and very few scholars had ever explored the two-person zero-sum game on MADM problems. In this paper, the weights of a MADM problem are obtained by formulating it as a two-person zero-sum game with multiple decision makers. The group equilibrium solution, i.e., consensus of weights and the resolution steps for such a group MADM game has also been originally developed and validated in this study. Finally, an actual case of selecting the appropriate portfolio decision for a paper company is illustrated.
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Potejana, Potejanasak, and Chakthong Thongchattu. "Application of Taguchi and Response Surface Methodologies for Surface Roughness in Rotary Tool Polishing Hardness Mould Steels." Applied Mechanics and Materials 87 (August 2011): 82–89. http://dx.doi.org/10.4028/www.scientific.net/amm.87.82.
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This research proposes a new application of 3-axis CNC milling machine for polishing the 60 HRC hardness steels. The rotary polishing tools are designed by refer to the end-mill ball nose’s design. The diamond powder are coated in rotary polishing tools by resinoid bonding method and concentrated in 4.4 karat/cm2. The Zig-milling tool paths are used to polish the hardness steel. After polishing, the confocal laser scanning microscope is used to analyze the arithmetic mean surface roughness of the hardness steels. The L12 orthogonal array of the Taguchi’s method is selected to conduct the matrix experiment to determine the optimal polishing process parameters. The diamond grit size and cutting speed of the rotary polishing tools, feed rate and step over of the tool path, the depth of polishing process penetration, and polishing time are used to study. The combination of the optimal level for each factor of the hardness steel polishing process are used to study again in the confirmation experiment. The predicted signal to noise ratio of smaller - the better under optimal condition are calculated by using the data from the experiment. The combination of the optimal level for each factor are used to study again in the confirmation experiment and the result show that polishing time was a dominant parameter for the surface roughness and the next was depth of penetration. The response surface design is then used to build the relationship between the input parameters and output responses. The experimental results show that the integrated approach does indeed find the optimal parameters that result in very good output responses in the rotary polishing tools polished hardness mould steel using CNC milling machine. The mean surface roughness of hardness steel polishing process is improved by the diamond rotary tools with the 3-axis CNC milling machine.
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Gasteiger, Josef, and Matthias Wiegner. "MOPSMAP v1.0: a versatile tool for the modeling of aerosol optical properties." Geoscientific Model Development 11, no. 7 (2018): 2739–62. http://dx.doi.org/10.5194/gmd-11-2739-2018.
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Abstract. The spatiotemporal distribution and characterization of aerosol particles are usually determined by remote-sensing and optical in situ measurements. These measurements are indirect with respect to microphysical properties, and thus inversion techniques are required to determine the aerosol microphysics. Scattering theory provides the link between microphysical and optical properties; it is not only needed for such inversions but also for radiative budget calculations and climate modeling. However, optical modeling can be very time-consuming, in particular if nonspherical particles or complex ensembles are involved. In this paper we present the MOPSMAP package (Modeled optical properties of ensembles of aerosol particles), which is computationally fast for optical modeling even in the case of complex aerosols. The package consists of a data set of pre-calculated optical properties of single aerosol particles, a Fortran program to calculate the properties of user-defined aerosol ensembles, and a user-friendly web interface for online calculations. Spheres, spheroids, and a small set of irregular particle shapes are considered over a wide range of sizes and refractive indices. MOPSMAP provides the fundamental optical properties assuming random particle orientation, including the scattering matrix for the selected wavelengths. Moreover, the output includes tables of frequently used properties such as the single-scattering albedo, the asymmetry parameter, or the lidar ratio. To demonstrate the wide range of possible MOPSMAP applications, a selection of examples is presented, e.g., dealing with hygroscopic growth, mixtures of absorbing and non-absorbing particles, the relevance of the size equivalence in the case of nonspherical particles, and the variability in volcanic ash microphysics. The web interface is designed to be intuitive for expert and nonexpert users. To support users a large set of default settings is available, e.g., several wavelength-dependent refractive indices, climatologically representative size distributions, and a parameterization of hygroscopic growth. Calculations are possible for single wavelengths or user-defined sets (e.g., of specific remote-sensing application). For expert users more options for the microphysics are available. Plots for immediate visualization of the results are shown. The complete output can be downloaded for further applications. All input parameters and results are stored in the user's personal folder so that calculations can easily be reproduced. The web interface is provided at https://mopsmap.net (last access: 9 July 2018) and the Fortran program including the data set is freely available for offline calculations, e.g., when large numbers of different runs for sensitivity studies are to be made.
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Naser, Marwah Abdulrazzaq, Muntadher Alsabah, Basheera M. Mahmmod, Nor K. Noordin, Sadiq H. Abdulhussain, and Thar Baker. "Downlink Training Design for FDD Massive MIMO Systems in the Presence of Colored Noise." Electronics 9, no. 12 (2020): 2155. http://dx.doi.org/10.3390/electronics9122155.
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Massive multiple-input multiple-output (MaMi) systems have attracted much research attention during the last few years. This is because MaMi systems are able to achieve a remarkable improvement in data rate and thus meet the immensely ongoing traffic demands required by the future wireless networks. To date, the downlink training sequence (DTS) for the frequency division duplex (FDD) MaMi communications systems have been designed based on the idealistic assumption of white noise environments. However, it is essential and more practical to consider the colored noise environments when designing an efficient DTS for channel estimation. To this end, this paper proposes a new DTS design by exploring the joint use of spatial channel and noise covariance matrices, when the channel is not reciprocal but the coherence block length remains limited. We derive an analytical solution for the mean square error (MSE) based on the proposed training design with colored noise. In addition, this paper exploits the method of random matrix theory to provide an analytical solution for the downlink (DL) achievable sum rate of the regularized zero forcing beamforming (RZFBF) precoder. Numerical results demonstrate that using the proposed DTS design, the MSE of the channel estimate is significantly reduced compared with the conventional training designs with white noise. Furthermore, the results show that the proposed pilot design markedly improves the DL achievable SR over the conventional training designs, especially at relatively low signal-to-noise-ratio (SNR) levels. This enables FDD MaMi systems to operate under more practical scenarios of colored noise and limited coherence time environments.
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Bhatia, Ramesh, John Briscoe, R. P. S. Malik, et al. "Water in the economy of Tamil Nadu, India: more flexible water allocation policies offer a possible way out of water-induced economic stagnation and will be good for the environment and the poor." Water Policy 8, no. 1 (2006): 1–13. http://dx.doi.org/10.2166/wp.2006.0001.
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The state of Tamil Nadu, India, is in the grips of a water crisis, with demand far outstripping supply. As the economy of the state grows, this crisis is going to become ever more serious. To date the focus of state water policy has been on trying to augment supplies, from within the state (even from desalinization) and from neighboring states. In addition, the water use is regulated in a way that does not encourage the highest value uses. International experience shows that supply-side measures must be complemented by demand-side measures and that practice must move away from fixed, command-and-control allocation policies towards flexible allocation mechanisms, which facilitate the voluntary movement of water from low to high-value uses. This study addresses the question of whether such a change in allocation policies is worth doing. It addresses this question by developing optimization models for each of the 17 river basins in Tamil Nadu (including an assessment of the economic value of water in different end-uses – agriculture, domestic and industry), then using an input–output model embedded in a social accounting matrix (SAM), to assess the impact of these changes on the state economy and on different rural and urban employment groups. The results suggest that a shift to a flexible water allocation system would bring major environmental, economic and social benefits to the state. Compared with the current “fixed sectoral allocation” policy, a flexible allocation policy would, in 2020, result in 15% less overall water used; 24% less water pumped from aquifers; 20% higher state income; with all strata, rich and poor, benefiting similarly, with one important exception, that of agricultural laborers.
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Astarita, Vittorio, Demetrio Carmine Festa, and Domenico W. E. Mongelli. "EcoSmart: An Application for Smartphones for Monitoring Driving Economy." Advanced Materials Research 827 (October 2013): 360–67. http://dx.doi.org/10.4028/www.scientific.net/amr.827.360.
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nstantaneous consumption models are designed to provide an accurate description of fuel consumption by relating the instantaneous rate of consumption with the vehicle acceleration, speed and the engine dynamics. In principle, instantaneous consumption models allow users to calculate the fuel consumption for any profile of vehicle operation. Some kind of models that take into account only driving dynamics can be used to describe the variability of consumption. The procedure used by this type of models is to establish reference matrices (related to specific time intervals) that for each combination of speed and acceleration determine the rate of fuel consumption. This paper Describes the design of a mobile application for the estimation of consumption, and user behavior, that applies models of instantaneous consumption. A preliminary experimental survey has been the carried out to obtain a large data base related to the acquisition of cinematic and engine parameters to allow the development of the mobile application. The experimental acquisition of parameters was accomplished in dynamic driving, connecting the OBDII port to different models of vehicles. With this procedure, reference matrices of fuel consumption for each specific class of emission (as required by ECE 15.03 - Directive 78/665/EEC and ECE 15.04 - Directive 83/351/EEC) have been obtained. The mobile phone application, after receiving as input the vehicle specifications provided by the user, can associate the specified matrix of consumption to the cinematic parameters (instant speed and acceleration obtained by GPS measures) and by using each pair of speed and acceleration can give an estimate of consumption values. At the end of the trip the user can take view of all device information on consumption also by geo-displaying the information on a map (showing the path and the related point by point consumptions). The output of the system, that can also provide information related to the dynamic behaviour and energy management in the user guide style, have been confronted with real consumption data. The advantage of the application is to estimate fuel consumption and driving style, from just GPS data, without connecting the phone to OBDII port.
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Cheng, I., X. Xu, and L. Zhang. "Overview of receptor-based source apportionment studies for speciated atmospheric mercury." Atmospheric Chemistry and Physics 15, no. 14 (2015): 7877–95. http://dx.doi.org/10.5194/acp-15-7877-2015.
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Abstract. Receptor-based source apportionment studies of speciated atmospheric mercury are not only concerned with source contributions but also with the influence of transport, transformation, and deposition processes on speciated atmospheric mercury concentrations at receptor locations. Previous studies applied multivariate receptor models including principal components analysis and positive matrix factorization, and back trajectory receptor models including potential source contribution function, gridded frequency distributions, and concentration–back trajectory models. Combustion sources (e.g., coal combustion, biomass burning, and vehicular, industrial and waste incineration emissions), crustal/soil dust, and chemical and physical processes, such as gaseous elemental mercury (GEM) oxidation reactions, boundary layer mixing, and GEM flux from surfaces were inferred from the multivariate studies, which were predominantly conducted at receptor sites in Canada and the US. Back trajectory receptor models revealed potential impacts of large industrial areas such as the Ohio River valley in the US and throughout China, metal smelters, mercury evasion from the ocean and the Great Lakes, and free troposphere transport on receptor measurements. Input data and model parameters specific to atmospheric mercury receptor models are summarized and model strengths and weaknesses are also discussed. Multivariate models are suitable for receptor locations with intensive air monitoring because they require long-term collocated and simultaneous measurements of speciated atmospheric Hg and ancillary pollutants. The multivariate models provide more insight about the types of Hg emission sources and Hg processes that could affect speciated atmospheric Hg at a receptor location, whereas back trajectory receptor models are mainly ideal for identifying potential regional Hg source locations impacting elevated Hg concentrations. Interpretation of the multivariate model output to sources can be subjective and challenging when speciated atmospheric Hg is not correlated with ancillary pollutants and when source emissions profiles and knowledge of Hg chemistry are incomplete. The majority of back trajectory receptor models have not accounted for Hg transformation and deposition processes and could not distinguish between upwind and downwind sources effectively. Ensemble trajectories should be generated to take into account the trajectory uncertainties where possible. One area of improvement that applies to all the receptor models reviewed in this study is the greater focus on evaluating the accuracy of the models at identifying potential speciated atmospheric mercury sources, source locations, and chemical and physical processes in the atmosphere. In addition to receptor model improvements, the data quality of speciated atmospheric Hg plays an equally important part in producing accurate receptor model results.
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Shubov, Marianna A. "Spectral analysis of Euler–Bernoulli beam model with distributed damping and fully non-conservative boundary feedback matrix." Asymptotic Analysis, August 23, 2021, 1–38. http://dx.doi.org/10.3233/asy-211722.
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The distribution of natural frequencies of the Euler–Bernoulli beam resting on elastic foundation and subject to an axial force in the presence of several damping mechanisms is investigated. The damping mechanisms are: ( i ) an external or viscous damping with damping coefficient ( − a 0 ( x )), ( ii ) a damping proportional to the bending rate with the damping coefficient a 1 ( x ). The beam is clamped at the left end and equipped with a four-parameter (α, β, κ 1 , κ 2 ) linear boundary feedback law at the right end. The 2 × 2 boundary feedback matrix relates the control input (a vector of velocity and its spacial derivative at the right end) to the output (a vector of shear and moment at the right end). The initial boundary value problem describing the dynamics of the beam has been reduced to the first order in time evolution equation in the state Hilbert space of the system. The dynamics generator has a purely discrete spectrum (the vibrational modes). Explicit asymptotic formula for the eigenvalues as the number of an eigenvalue tends to infinity have been obtained. It is shown that the boundary control parameters and the distributed damping play different roles in the asymptotical formulas for the eigenvalues of the dynamics generator. Namely, the damping coefficient a 1 and the boundary controls κ 1 and κ 2 enter the leading asymptotical term explicitly, while damping coefficient a 0 appears in the lower order terms.