Repetitive Calculations Research Articles

Simultaneous diagnosis and retrofit of heat exchanger network via individual process stream mapping

Medium and large scale industries typically consume large amounts of energy, and are under pressure to increase energy efficiency and reduce energy wastages. Conventional insight-based heat exchanger network (HEN) retrofit methods typically combine graphical visualisation and algebraic tools to manage different retrofit stages. These stages often involve repetitive calculations of approach temperature, enthalpy balance and heat transfer area to assess the HEN feasibility and cost-effectiveness. This paper extends the individual stream temperature versus enthalpy plot (STEP) methodology that was introduced for HEN synthesis, to HEN retrofit. The STEP retrofit method proposed in this work enables users to simultaneously diagnose and retrofit existing HEN by using only the STEP diagram that maintains the characteristics of individual process streams. Users can graphically perform individual stream mapping without having to calculate stream enthalpies or to check for minimum temperature approach (ΔTmin) violation during retrofit. Application of the new STEP retrofit method on an industrial case study demonstrates its advantages in terms of user interactiveness, simplicity of use, flexibility to customise the methodology to achieve retrofit goals of plant owners, and the least amount of efforts needed to achieve comparable results as those of established retrofit methods.

Estimating electromechanical oscillation modes from synchrophasor measurements in bulk power grids using FSSI

Multi-order stochastic subspace identification (MOSSI) has been extensively used to estimate the electromechanical oscillation modes from probing, ambient and ringdown data. It has been validated with good performances, while the computational burden is still a major obstacle. This study develops a fast iterative MOSSI (FSSI) approach for computational enhancement of MOSSI in mode estimation. In the proposed approach, an initial cluster of eigenvalues is formulated through FSSI with repetitive calculations (RCs), and electromechanical oscillation mode separation (EOMS) is utilised to discriminate the electromechanical modes. The RCs within the FSSI is calculated through changing the model order successively over the defined range given by a mean of singular values based order determination strategy. Additionally, the proposed approach is highly reliable against prevalent measurement noises owing to RCs and the EOMS. The performance of the proposed method is evaluated in Kundur's two-area test system by comparing with MOSSI, Prony and autoregressive moving average exogenous. Its applicability for both the ringdown and ambient data is also demonstrated with the phasor measurement units field-measurement data from the China Southern Power Grid. The results confirmed the accuracy, robustness and efficiency of the proposed approach for oscillation mode estimation.

Establishment of magnetic resonance imaging 3D reconstruction technology of orbital soft tissue and its preliminary application in patients with thyroid-associated ophthalmopathy.

Effective management of thyroid-associated ophthalmopathy (TAO) requires precise identification of the disease activity period as it is responsive to immunosuppressive treatment. Quantitative evaluations of orbital soft tissue are useful for analysing disease stages. We aimed to establish a method for orbital soft tissue volume calculation based on magnetic resonance imaging (MRI) data using 3D reconstruction technology. Furthermore, we validated the accuracy and precision of this method and investigated volume differences between patients with TAO and healthy individuals. Using Mimics software for 3D reconstruction based on orbital MRI data, we quantitatively measured orbital fat volume (FV) and extraocular muscle volume (MV) using a manual phantom, and in patients with TAO and healthy volunteers (n=10 each). The phantom was made using a combination of butter and chicken muscle and 2 observers measured its volume. Volume calculations were compared to a previously established standard volume. One observer measured a typical TAO case 10 times to calculate intra-observer variability while 3 observers independently measured 10 patients with TAO each to calculate interobserver variability. Orbital soft tissue volumes between 10 patients with TAO and 10 healthy individuals were compared. The precision of calculations for the phantom between the 2 observers varied from -4.60% to -2.78% for FV and between -4.13% to 0.71% for MV. Mean differences among repetitive calculations were lower than 4%, except during measurement of MV, which was 5.84%. The intraclass correlation coefficient varied from 0.976 to 0.996. FV was 15.53±3.06mL in patients with TAO and 11.32±1.68mL(P=.001)in healthy individuals, while MV was 3.19±0.82mL in patients with TAO and 2.45±0.57mL(P=.030)in healthy individuals. This method of calculating orbital soft tissue volumes based on MRI data and 3D reconstruction is both reliable and accurate as it yielded significant differences in tissue volume between patients with TAO and healthy individuals.

A Versatile Software for Construction of the Master Sintering Curve

Several models have been developed over the last years to study the microstructure development of ceramic and metal powders during sintering. Among the most utilized methodology one may find the Arrhenius and the so-called Master Sintering Curve (MSC). Both models involve manipulation of a large number of data, and repetitive and time-consuming calculations. In this work, was developed a versatile and friendly-user software for a PC-type computer encompassing both methodologies. The software is flexible allowing for kinetic data evaluation such as the activation energy for sintering and sintering maps. Details of the software along with its application to investigate the sintering process of 10 mol% gadolinia-doped ceria are described.

Progressive Line Processing of Kernel RX Anomaly Detection Algorithm for Hyperspectral Imagery.

The Kernel-RX detector (KRXD) has attracted widespread interest in hyperspectral image processing with the utilization of nonlinear information. However, the kernelization of hyperspectral data leads to poor execution efficiency in KRXD. This paper presents an approach to the progressive line processing of KRXD (PLP-KRXD) that can perform KRXD line by line (the main data acquisition pattern). Parallel causal sliding windows are defined to ensure the causality of PLP-KRXD. Then, with the employment of the Woodbury matrix identity and the matrix inversion lemma, PLP-KRXD has the capacity to recursively update the kernel matrices, thereby avoiding a great many repetitive calculations of complex matrices, and greatly reducing the algorithm’s complexity. To substantiate the usefulness and effectiveness of PLP-KRXD, three groups of hyperspectral datasets are used to conduct experiments.

Partial atomic multipoles for internally consistent microelectrostatic calculations

An extension of the extant microelectrostatic methodologies, based on the concept of distributed generalized polarizability matrix derived from the Coupled Perturbed Hartree-Fock (CPHF) equations, is proposed for self-consistent calculation of charge carrier and charge-transfer (CT) state electrostatic energies in molecular solids, including the doped, defected and disordered ones. The CPHF equations are solved only once and the generalized molecular polarizability they yield enables low cost iterations that mutually adjust the molecular electronic distributions and the local electric field in which the molecules are immersed. The approach offers a precise picture of molecular charge densities, accounting for atomic partial multipoles up to order 2, which allows one to reproduce the recently reported large charge-quadrupole contributions to CT state energies in low-symmetry local environments. It is particularly well suited for repetitive calculations for large clusters (up to 300,000 atoms), and may potentially be useful for describing electrostatic solvent effects. © 2017 Wiley Periodicals, Inc.

Kajian Awal Penyusunan Algoritma Perhitungan Luas Tanah dan Faktor Koreksi dengan Metode Poligon Terbuka dan Tertutup

Data for land squares area and land volumes are strongly needed for private company neither is the government. Nowadays, the calculations of land squares are done manually, which need long and repetitive calculations. It is unfortunately risky for the researches. On the other side, none of the standard methods is used to calculate the volume of land burying. One of the alternatives when we intend to minimize the error of the calculation and measurement process is to integrate the step of calculation and measurement processes themselves. The underlined means to practice the automation on the recitation of several measurement output, and then the calculation of land squares, contour drawing, and land volumes can automatically be done. On the calculation of area squares, contour drawing, and land volumes, data of the measurements are put into calculation algorithm and are expected to be directly used in calculating the land squares, contour drawing, and land volumes, also automatically make the correction on the errors in order to minimize them. In this research, no hardware development is being developed. The author intended only to compose a calculation of algorithm to calculate land squares. Keywords: Land Squares, Algorithm, Integrate

Structural reliability simulation for the latching mechanism in MEMS-based Safety and Arming device

Based on the deterministic performance analysis of latching mechanism in MEMS (micro-electro-mechanical system)-based Safety and Arming device (S&A device), probabilistic algorithms and Kriging approximation method coupling with finite element simulation are used to quantify the effect of input uncertainties on the response metrics of the mechanism. It firstly uses performance function to represent the failure of the latching mechanism mathematically, and then constructs the corresponding reliability model according to structural reliability theory. In order to relieve the burden of further reliability and sensitivity calculations, Kriging interpolation technique is adopted to approximate the performance function and hence simplify the reliability model. Samples of input variables and the corresponding response, which all together serve as the inputs of Kriging approximation, are gotten through finite element simulations based on the design of experiments. An efficient CAE software integration method is proposed to facilitate the repetitive FE-based calculations of those samples. Finally, FORM (First Order Second Moment Method) is utilized to get the reliability index and its sensitivities with respect to the input random variables and their parameters, which can not only be employed for reliability assessment of the latching mechanism, but also can help to identify key factors for additional structural improvements.

A statistical model of the wave field in a bounded domain

Numerical simulations of plasma heating with radiofrequency waves often require repetitive calculations of wave fields as the plasma evolves. To enable effective simulations, bench marked formulas of the power deposition have been developed. Here, a statistical model applicable to waves with short wavelengths is presented, which gives the expected amplitude of the wave field as a superposition of four wave fields with weight coefficients depending on the single pass damping, as. The weight coefficient for the wave field coherent with that calculated in the absence of reflection agrees with the coefficient for strong single pass damping of an earlier developed heuristic model, for which the weight coefficients were obtained empirically using a full wave code to calculate the wave field and power deposition. Antennas launching electromagnetic waves into bounded domains are often designed to produce localised wave fields and power depositions in the limit of strong single pass damping. The reflection of the waves changes the coupling that partly destroys the localisation of the wave field, which explains the apparent paradox arising from the earlier developed heuristic formula that only a fraction as2(2−as) and not as of the power is absorbed with a profile corresponding to the power deposition for the first pass of the rays. A method to account for the change in the coupling spectrum caused by reflection for modelling the wave field with ray tracing in bounded media is proposed, which should be applicable to wave propagation in non-uniform media in more general geometries.

Real-Time Anomaly Detection Based on a Fast Recursive Kernel RX Algorithm

Abstract: Real-time anomaly detection has received wide attention in remote sensing image processing because many moving targets must be detected on a timely basis. A widely-used anomaly detection algorithm is the Reed-Xiaoli (RX) algorithm that was proposed by Reed and Yu. The kernel RX algorithm proposed by Kwon and Nasrabadi is a nonlinear version of the RX algorithm and outperforms the RX algorithm in terms of detection accuracy. However, the kernel RX algorithm is computationally more expensive. This paper presents a novel real-time anomaly detection framework based on the kernel RX algorithm. In the kernel RX detector, the inverse covariance matrix and the estimated mean of the background data in the kernel space are non-causal and computationally inefficient. In this work, a local causal sliding array window is used to ensure the causality of the detection system. Using the matrix inversion lemma and the Woodbury matrix identity, both the inverse covariance matrix and estimated mean can be recursively derived without extensive repetitive calculations, and, therefore, the real-time kernel RX detector can be implemented and processed pixel-by-pixel in real time. To substantiate its effectiveness and utility in real-time anomaly detection, real hyperspectral data sets are utilized for experiments.

Comparison of Rigorous Design Procedure with Approximate Design Procedure for Variable Sampling Plans Indexed by Quality Loss

Traditional acceptance sampling plans have focused on the proportion of nonconforming items as an attribute criterion for quality. In today’s modern quality management under high quality production environments, the reduction of the deviation from a target value in a quality characteristic has become the most important purpose. In consequence, various inspection plans for the purpose of reducing the deviation from the target value in the quality characteristic have been investigated. In this case, a concept of the quality loss evaluated by the deviation from the target value has been accepted as the variable evaluation criterion of quality. Further, some quality measures based on the quality loss have been devised; e.g. the process loss and the process capability index. Then, as one of inspection plans based on the quality loss, the rigorous design procedure for the variable sampling plan having desired operating characteristics (VS-OC plan) indexed by the quality loss has been proposed by Yen and Chang in 2009. By the way, since the estimator of the quality loss obeys the non-central chi-square distribution, the rigorous design procedure for the VS-OC plan indexed by the quality loss is complicated. In particular, the rigorous design procedure for the VS-OC plan requires a large number of the repetitive and complicated numerical calculation about the non-central chi-square distribution. On the other hand, an approximate design procedure for the VS-OC plan has been proposed before the proposal of the above rigorous design procedure. The approximate design procedure for the VS-OC plan has been constructed by combining Patnaik approximation relating the non-central chi-square distribution to the central chi-square distribution and Wilson-Hilferty approximation relating the central chi-square distribution to the standard normal distribution. Then, the approximate design procedure has been devised as a convenient procedure without complicated and repetitive numerical calculations. In this study, through some comparisons between the rigorous and approximate design procedures, the applicability of the approximate design procedure has been confirmed.

Isogeometric analysis-based reduced order modelling for incompressible linear viscous flows in parametrized shapes

In this work we provide a combination of isogeometric analysis with reduced order modelling techniques, based on proper orthogonal decomposition, to guarantee computational reduction for the numerical model, and with free-form deformation, for versatile geometrical parametrization. We apply it to computational fluid dynamics problems considering a Stokes flow model. The proposed reduced order model combines efficient shape deformation and accurate and stable velocity and pressure approximation for incompressible viscous flows, computed with a reduced order method. Efficient offline–online computational decomposition is guaranteed in view of repetitive calculations for parametric design and optimization problems. Numerical test cases show the efficiency and accuracy of the proposed reduced order model.

A Reduced-Boron OPR1000 Core Based on the BigT Burnable Absorber

Reducing critical boron concentration in a commercial pressurized water reactor core offers many advantages in view of safety and economics. This paper presents a preliminary investigation of a reduced-boron pressurized water reactor core to achieve a clearly negative moderator temperature coefficient at hot zero power using the newly-proposed “Burnable absorber-Integrated Guide Thimble” (BigT) absorbers. The reference core is based on a commercial OPR1000 equilibrium configuration. The reduced-boron ORP1000 configuration was determined by simply replacing commercial gadolinia-based burnable absorbers with the optimized BigT-loaded design. The equilibrium cores in this study were directly searched via repetitive Monte Carlo depletion calculations until convergence. The results demonstrate that, with the same fuel management scheme as in the reference core, application of the BigT absorbers can effectively reduce the critical boron concentration at the beginning of cycle by about 65 ppm. More crucially, the analyses indicate promising potential of the reduced-boron OPR1000 core with the BigT absorbers, as its moderator temperature coefficient at the beginning of cycle is clearly more negative and all other vital neutronic parameters are within practical safety limits. All simulations were completed using the Monte Carlo Serpent code with the ENDF/B-VII.0 library.

Upscaling with the dynamic two-layer classification concept (D2C): TreeMig-2L, an efficient implementation of the forest-landscape model TreeMig

Abstract. Models used to investigate impacts of climatic changes on spatio-temporal vegetation dynamics need to balance required accuracy with computational feasibility. To enhance the computational efficiency of these models, upscaling methods are required that maintain key fine-scale processes influencing vegetation dynamics. In this paper, an adjustable method – the dynamic two-layer classification concept (D2C) – for the upscaling of time- and space-discrete models is presented. D2C aims to separate potentially repetitive calculations from those specific to single grid cells. The underlying idea is to extract processes that do not require information about a grid cell's neighbourhood to a reduced-size non-spatial layer, which is dynamically coupled to the original two-dimensional layer. The size of the non-spatial layer is thereby adaptive and depends on dynamic classifications according to pre-specified similarity criteria. I present how D2C can be used in a model implementation on the example of TreeMig-2L, a new, efficient version of the intermediate-complexity forest-landscape model TreeMig. To discuss the trade-off between computational expenses and accuracy, as well as the applicability of D2C, I compare different model stages of TreeMig-2L via simulations of two different application scenarios. This comparison of different model stages demonstrates that applying D2C can strongly reduce computational expenses of processes calculated on the new non-spatial layer. D2C is thus a valuable upscaling method for models and applications in which processes requiring information about the neighbourhood constitute the minor share of the overall computational expenses.

Stochastic subspace identification‐based approach for tracking inter‐area oscillatory modes in bulk power system utilising synchrophasor measurements

Stochastic subspace identification (SSI) methods have been widely employed for oscillatory mode identification on probing and ambient data and are reported to have good performances. This work proposes a novel SSI-based approach for identifying dominant oscillatory mode from measurement data and extends the application of SSI to ringdown condition. The proposed approach first constructs an initial cluster of eigenvalues from SSI with repetitive calculations and then utilises a novel hierarchical clustering method to extract the dominant modes from the initial cluster. The repetitive calculations within the SSI are performed through varying the model order over a range defined by a novel initial order determination process. By doing so the challenge of model order determination for SSI-based methods is resolved. Moreover, benefiting from the repetitive calculations and the clustering process, the proposed approach is highly immune to prevalent noises in the measurements. Finally, the proposed approach is applied and validated on the field-measurement data from the phasor measurement units of China Southern Power Grid (CSG) through comparisons with Prony, ARMAX, and Monte Carlo methods. Test results demonstrate that the proposed approach performs with high accuracy, robustness, and efficiency in CSG.

Chapter 2 - A self-assessment, and a tutorial in Excel

<p>QUESTIONS ASKED</p><ul><li>Am I aware of the basics of scientific writing required to write an informative report?</li><li>Do I remember the basics of mathematics?</li><li>How do I use statistics to plan and analyze my field or experimental data?</li><li>How to lose the fear of using a spreadsheet?</li><li>How to do basic repetitive calculations?</li><li>How to present figures and reports in scientific style?</li><li>How to efficiently select and summarize sub-groups of data?</li></ul>

Chapter 3. Excel basics

<p><span style="background: white; color: black; line-height: 107%; font-family: 'Verdana',sans-serif; font-size: 11pt; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;" lang="EN-US">This introductory chapter of CONΣERV IT deals with the following preparatory skills:</span></p><p>- How to lose the fear of using a spreadsheet?<br />- How to do basic repetitive calculations?<br />- How to present figures and reports in scientific style?<br />- How to efficiently select and summarize sub-groups of data?</p><p><span style="background: white; color: black; line-height: 107%; font-family: 'Verdana',sans-serif; font-size: 11pt; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;" lang="EN-US"><br /></span></p><p><span style="background: white; color: black; line-height: 107%; font-family: 'Verdana',sans-serif; font-size: 11pt; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;" lang="EN-US"><a href="/index.php/SapEdu/article/downloadSuppFile/3513/137" target="_blank">Excel basics</a><br /></span></p>

Agile structural analysis for fabrication-aware shape editing

This paper presents an agile simulation-aided shape editing system for personal fabrication applications. The finite element structural analysis and geometric design are seamlessly integrated within our system to provide users interactive structure analysis feedback during mesh editing. Observing the fact that most editing operations are actually local, a domain decomposition framework is employed to provide unified interface for shape editing, FEM system updating and shape optimization. We parameterize entries of the stiffness matrix as polynomial-like functions of geometry editing parameters thus the underlying FEM system can be rapidly synchronized once edits are made. A local update scheme is devised to re-use the untouched parts of the FEM system thus a lot repetitive calculations are avoided. Our system can also perform shape optimizations to reduce high stresses in model while preserving the appearance of the model as much as possible. Experiments show our system provides users a smooth editing experience and accurate feedback.

Спектрально-аналитический метод распознавания неточных повторов в символьных последовательностях

Proposed are theoretical basis and algorithmic implementation of spectral-analytical method of recognition of repeats in character sequences. The theoretical justification is based on the theorem on equivalent representation of the character sequence by the vector of continuous characteristic functions. Comparison of fragments of characteristic functions is performed in the standard metric in Euclidean space of expansion coefficients of the Fourier series of orthogonal polynomials. An essential feature of this approach is the ability to evaluate repeats at different scales. Another important feature is the possibility of efficient parallelization of data. In the development of algorithms we preferred scheme of computing with a minimal amount of references to memory, implying repetitive calculations and evaluations on demand. In this paradigm, proposed is an algorithm for calculating the coefficients of expansions in the orthogonal polynomials through the use of recurrence relations. It is shown that the algorithm for calculating the coefficients of expansions in the orthogonal polynomials can be effectively vectorized by computing with a fixed vector length. Parallelization and vectorization implemented using the OpenMP standard and extension Cilk Plus of language C/C++. The developed method effectively scales, depending on the parameters of the problem and the number of processor cores on systems with shared memory.

АВТОМАТИЗОВАНИЙ СИНТЕЗ НЕСИМЕТРИЧНИХ ТРИФАЗНИХ ОБМОТОК

The article presents the results of the software of the automated synthesis of two-and three-phase windings with a reduced level of asymmetry. The necessity of using such a weakly asymmetric windings periodically arises on the enterprises specializing in the repair of electrical machines, so the task of such symmetrize windings design is relevant. Algorithm of synthesis of these multi-phase windings is based on balancing - achieving of practical symmetry on harmonics symmetry that ensures the correct application of the method of symmetrical components to perform a detailed harmonic analysis of the winding MDS. Implementation of this algorithm in manual mode requires multiple graphic design of vector diagrams and performing of repetitive routine calculations, therefore characterized by higher labor input. The proposed software is characterized by a user-friendly interface. Both automated and manual input of initial data, as well as their operational adjustment are provided. Visualization module of vector diagrams eliminates the need of manual graphic design, on the order reduces the time required in the process of balancing using the method of successive approximations and provides almost complete symmetry by working harmonica. On the second stage the compliance of detailed harmonic analysis and printing of the obtained results or saving in files are provided so you can use them for subsequent determination of operational properties of electric machines, in which such winding are used. Effectiveness of the developed software is illustrated by the example of symmetrize three-phase winding synthesis with demonstration of performance technology of each stage of design and comparing of its electromagnetic properties before and after balancing.