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A robust and efficient algorithm for vapor-liquid-equilibrium/liquid-liquid-equilibrium (VLE/LLE) phase boundary tracking

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CHEMICAL ENGINEERING SCIENCE 2023年 266卷

作者： Chen, Zhuo Xu, Lingfei Zhou, Ying Li, Ruixue Li, Huazhou Univ Alberta Fac Engn Sch Min & Petro Engn Edmonton AB T6G 1H9 Canada Chengdu Univ Technol Coll Energy Chengdu 610059 Peoples R China Chengdu Univ Technol State Key Lab Oil & Gas Reservoir Geol & Exploita Chengdu 610059 Peoples R China Univ Alberta Petro Engn Edmonton AB Canada

A novel phase-boundary tracking method is proposed to precisely capture the vapor-liquid/liquid-asphaltene and vapor-liquid/liquid-liquid two-phase boundaries in pressure-temperature and pressure-composition phase diagrams. The two-phase boundary determined by the proposed phase -boundary tracking method intersects the three-phase boundary at the apex of the three-phase region, which indicates the continuation of the three-phase region. The calculated two-phase boundaries also agree well with those documented in the *** 2022 Elsevier Ltd. All rights reserved.

关键词： Vapor -liquid equilibria Liquid -liquid equilibria Phase diagram Phase boundary Equation of state algorithm development

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A novel four-phase equilibrium calculation algorithm for water/ hydrocarbon systems containing gas hydrates

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CHEMICAL ENGINEERING SCIENCE 2023年 267卷

作者： Chen, Xin Li, Huazhou Univ Alberta Fac Engn Sch Min & Petr Engn Edmonton AB T6G 1H9 Canada Hainan Univ State Lab Marine Resource Utilizat South China Sea Haikou 570228 Peoples R China

In this study, we developed an algorithm for vapor-liquid-aqueous-hydrate four-phase equilibrium cal-culations. The algorithm was formulated in a stage-wise manner: a stability test was first conducted, fol-lowed by flash calculations if instability was determined. In addition to using the van der Waals- Platteeuw model for predicting the presence of a hydrate phase, we proposed a novel criterion for deter-mining the onset of hydrate dissociation. Sample calculations were conducted for several fluids. We suc-cessfully plotted the pressure-temperature and pressure-composition phase diagrams of these fluids by conducting point-to-point equilibrium calculations with the newly developed four-phase equilibrium calculation algorithm.(c) 2022 Elsevier Ltd. All rights reserved.

关键词： Multiphase equilibrium calculation Gas hydrates Phase diagram algorithm development

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Proton radiography in three dimensions: A proof of principle of a new technique

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MEDICAL PHYSICS 2013年第10期40卷 101917-101917页

作者： Raytchev, Milen Seco, Joao Harvard Univ Sch Med Dept Radiat Oncol Boston MA 02114 USA Massachusetts Gen Hosp Boston MA 02114 USA

Purpose: Monte Carlo simulations were used to investigate a range of phantom configurations to establish enabling three-dimensional proton radiographic techniques. Methods: A large parameter space of stacked phantom geometries composed of tissue inhomogeneity materials such as lung, bone, and cartilage inserted within water background were simulated using a purposefully modified version of TOPAS, an application running on top of the GEANT4 Monte Carlo code. The phantoms were grouped in two classes, one with the inhomogeneity inserted only half-way in the lateral direction and another with complete inhomogeneity insertion. The former class was used to calculate the track count and the energy fluence of the protons as they exit the phantoms either having traversed the inhomogeneity or not. The latter class was used to calculate one yield value accounting for loss of protons due to physical processes only and another yield value accounting for deliberately discarded protons due to large scattering angles. A graphical fingerprinting method was developed to determine the inhomogeneity thickness and location within the phantom based on track count and energy fluence information. Two additional yield values extended this method to the general case which also determines the inhomogeneity material and the phantom thickness. Results: The graphical fingerprinting method was manually validated for two, and automatically tested for all, tissue materials using an exhaustive set of inhomogeneity geometries for 16 cm thick phantoms. Unique recognition of test phantom configurations was achieved in the large majority of cases. The method in the general case was further tested using an exhaustive set of inhomogeneity and phantom tissues and geometries where the phantom thicknesses ranged between 8 and 24 cm. Unique recognition of the test phantom configurations was achieved only for part of the phantom parameter space. The correlations between the remaining false positive recognition

关键词： 3D proton radiography proton radiography algorithm development 3D computed radiography Monte Carlo

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New benchmark for image segmentation evaluation

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JOURNAL OF ELECTRONIC IMAGING 2007年第3期16卷 033011.1-033011.16页

作者： Ge, Feng Wang, Song Liu, Tiecheng Virginia Tech Dept Elect & Comp Engn Blacksburg VA 24061 USA Univ S Carolina Dept Comp Sci & Engn Columbia SC 29208 USA

Image segmentation and its performance evaluation are very difficult but important problems in computer vision. A major challenge in segmentation evaluation comes from the fundamental conflict between generality and objectivity: For general-purpose segmentation, the ground truth and segmentation accuracy may not be well defined, while embedding the evaluation in a specific application, the evaluation results may not be extensible to other applications. We present a new benchmark to evaluate five different image segmentation methods according to their capability to separate a perceptually salient structure from the background with a relatively small number of segments. This way, we not only find a large variety of images that satisfy the requirement of good generality, but also construct ground-truth segmentations to achieve good objectivity. We also present a special strategy to address two important issues underlying this benchmark: (1) most image-segmentation methods are not developed to directly extract a single salient structure;(2) many real images have multiple salient structures. We apply this benchmark to evaluate and compare the performance of several state-of-the-art image segmentation methods, including the normalized-cut method, the watershed method, the efficient graph-based method, the mean-shift method, and the ratio-cut method. (c) 2007 SPIE and IS&T.

关键词： Image segmentation Databases Image processing algorithms and systems Gaussian filters algorithm development Computer vision technology Machine vision MATLAB Medical imaging Video surveillance

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An algorithmic approach for optimising biometric systems using liveness and coercion detection

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COMPUTERS & SECURITY 2020年 94卷 101831-101831页

作者： Matthew, Peter Canning, Susan Edge Hill Univ Dept Comp Sci Ormskirk Lancs England

This paper looks at the possibility of creating an algorithm that will combine liveness and coercion modalities, along with organisational factors such as workforce composition. The hypothesis is that the algorithm can produce a value that can further be used to compare different setups of biometric security for self-optimisation by taking in the context of technique compatibility and user requirements. To this end, the algorithm focuses on four main aspects: time, participants, anomalous user-bases, and device redundancy inside a typical organisation. An experimental methodology has been used, focusing on the development of the algorithm, its associated effects, and how different parameters can be reliably estimated. After testing, the algorithm is proved to work as it creates an appropriate value, called the security value, which can be used to discover the best combinations of modalities for fusion development or practical installation for a given situation. There are some issues with this primarily due to data provision, the requirements for more data to parse through the algorithm, and finally, the need for a suitable interface, otherwise it may be too complex for efficient usage in a traditional security environment. There are potential implications within a general security application such as liveness and coercion multimodal fusion and autonomous system development and pervasive environments, allowing dynamic security systems to be developed. However, the main focus of this algorithm is to highlight the fusion of liveness and coercion detection and how they can be best applied to specific security scenarios. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Biometric security Liveness Coercion algorithm development Fusion Personalisation

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Re-inspiring the genetic algorithm with multi-level selection theory: multi-level selection genetic algorithm

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BIOINSPIRATION & BIOMIMETICS 2018年第5期13卷 056007-056007页

作者： Sobey, A. J. Grudniewski, P. A. Univ Southampton Fluid Struct Interact Univ Rd Southampton SO17 1BJ Hants England

Genetic algorithms are integral to a range of applications. They utilise Darwin's theory of evolution to find optimal solutions in large complex spaces such as engineering, to visualise the design space, artificial intelligence, for pattern classification, and financial modelling, improving predictions. Since the original genetic algorithm was developed, new theories have been proposed which are believed to be integral to the evolution of biological systems. However, genetic algorithm development has focused on mathematical or computational methods as the basis for improvements to the mechanisms, moving it away from its original evolutionary inspiration. There is a possibility that the new evolutionary mechanisms are vital to explain how biological systems developed but they are not being incorporated into the genetic algorithm;it is proposed that their inclusion may provide improved performance or interesting feedback to evolutionary theory. Multi-level selection is one example of an evolutionary theory that has not been successfully implemented into the genetic algorithm and these mechanisms are explored in this paper. The resulting multi-level selection genetic algorithm (MLSGA) is unique in that it has different reproduction mechanisms at each level and splits the fitness function between these mechanisms. There are two variants of this theory and these are compared with each other alongside a unified approach. This paper documents the behaviour of the two variants, which show a difference in behaviour especially in terms of the diversity of the population found between each generation. The multi-level selection 1 variant moves rapidly towards the optimal front but with a low diversity amongst its children. The multi-level selection 2 variant shows a slightly slower evolution speed but with a greater diversity of children. The unified selection exhibits a mixed behaviour between the original variants. The different performance of these variants can be utilised t

关键词： multi-level selection multi-objective optimisation single objective optimisation evolutionary theory algorithm development

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Seamless retrievals of chlorophyll-a from Sentinel-2 (MSI) and Sentinel-3 (OLCI) in inland and coastal waters: A machine-learning approach

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REMOTE SENSING OF ENVIRONMENT 2020年第0期240卷 111604-000页

作者： Pahlevan, Nima Smith, Brandon Schalles, John Binding, Caren Cao, Zhigang Ma, Ronghua Alikas, Krista Kangro, Kersti Gurlin, Daniela Nguyen Ha Matsushita, Bunkei Moses, Wesley Greb, Steven Lehmann, Moritz K. Ondrusek, Michael Oppelt, Natascha Stumpf, Richard NASA Goddard Space Flight Ctr Greenbelt MD 20771 USA SSAI Lanham MD USA Creighton Univ Dept Biol Omaha NE 68178 USA Environm & Climate Change Canada Burlington ON Canada Nanjing Inst Geog & Limnol Nanjing Peoples R China Univ Tartu Tartu Estonia Wisconsin Dept Nat Resources Madison WI USA Vietnam Natl Univ VNU Univ Sci Hanoi Vietnam Univ Tsukuba Ibaraki Japan Naval Res Lab Washington DC 20375 USA Univ Wisconsin Space Sci & Engn Madison WI USA Xerra Earth Observat Inst Hamilton New Zealand Univ Waikato Hamilton New Zealand NOAA Ctr Satellite Applicat & Res College Pk MD USA Univ Kiel Dept Geog Kiel Germany NOAA Natl Ctr Coastal Sci Studies Silver Spring MD USA

Consistent, cross-mission retrievals of near-surface concentration of chlorophyll-a (Chla) in various aquatic ecosystems with broad ranges of trophic levels have long been a complex undertaking. Here, we introduce a machine-learning model, the Mixture Density Network (MDN), that largely outperforms existing algorithms when applied across different bio-optical regimes in inland and coastal waters. The model is trained and validated using a sizeable database of co-located Chla measurements (n = 2943) and in situ hyperspectral radiometric data resampled to simulate the Multispectral Instrument (MSI) and the Ocean and Land Color Imager (OLCI) onboard Sentinel-2A/B and Sentinel-3A/B, respectively. Our performance evaluations of the model, via two-thirds of the in situ dataset with Chla ranging from 0.2 to 1209 mg/m(3) and a mean Chla of 21.7 mg/m(3), suggest significant improvements in Chla retrievals. For both MSI and OLCI, the mean absolute logarithmic error (MAE) and logarithmic bias (Bias) across the entire range reduced by 40-60%, whereas the root mean squared logarithmic error (RMSLE) and the median absolute percentage error (MAPE) improved two-to-three times over those from the state-of-the-art algorithms. Using independent Chla matchups (n < 800) for Sentinel-2A/B and -3A, we show that the MDN model provides most accurate products from recorded images processed via three different atmospheric correction processors, namely the SeaWiFS Data Analysis System (SeaDAS), POLYMER, and ACOLITE, though the model is found to be sensitive to uncertainties in remote-sensing reflectance products. This manuscript serves as a preliminary study on a machine-learning algorithm with potential utility in seamless construction of Chla data records in inland and coastal waters, i.e., harmonized, comparable products via a single algorithm for MSI and OLCI data processing. The model performance is anticipated to enhance by improving the global representativeness of the training data as

关键词： Chlorophyll-a Sentinel missions Water quality Inland and coastal waters Earth observation Machine learning algorithm development

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A novel high speed multi-objective evolutionary optimisation algorithm ⁎

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IFAC-PapersOnLine 2020年第2期53卷 6756-6761页

作者： Viviane De Buck Ihab Hashem Jan Van Impe BioTeC+ Chemical and Biochemical Process Technology and Control Department of Chemical Engineering KU Leuven Belgium

Multi-objective optimisation problems (MOOPs) consider multiple objectives simultaneously. Solving these problems does not render one unique solution but instead a set of equally optimal solutions, i.e., the Pareto front. The goal of solving a MOOP is to accurately and efficiently approximate the Pareto front. The use of evolutionary optimisation algorithms is widespread in this discipline. During each iteration, parent solutions are combined and mutated to create new offspring solutions. Both populations are subsequently combined and sorted. Only the N fittest solutions of the combined set are selected as the parent solutions for the subsequent iteration. The fitness of a solution is defined by its convergence to the Pareto front and its contribution to the overall solution diversity. Widely used evolutionary algorithms, like NSGA-II (Deb et al., 2002), use non-dominated sorting to assess the convergence of solutions and the concept of crowding distance to ensure a high solution diversity. Both concepts, however, require that all N solutions of the population are compared with all other ( N — 1) solutions for both aspects, and this for all M objectives. This results in a computational complexity of O(MN 2 ). In this contribution, a novel evolutionary algorithm is presented, boasting a significantly lower computational complexity of O(N log (N)). This is achieved by subdividing the feasible space into angular sections. Solutions are scored based on their distance from the current Utopia point and the overall crowdedness of their respective section. Sorting the population based on the attributed scores allows the selection of the N fittest solutions, without having to mutually compare them.

关键词： Evolutionary optimisation algorithms algorithm development

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First lunar-light mapping of nighttime dust season oceanic aerosol optical depth over North Atlantic from space

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REMOTE SENSING OF ENVIRONMENT 2024年 312卷

作者： Zhou, Meng Wang, Jun Chen, Xi Wang, Yi Colarco, Peter R. Levy, Robert C. Miller, Steven D. Univ Iowa Interdisciplinary Grad Program Geoinformat Iowa City IA 52242 USA Univ Iowa Ctr Global & Reg Environm Res Iowa City IA 52242 USA Univ Iowa Iowa Technol Inst Iowa City IA 52242 USA Univ Maryland Baltimore Cty Goddard Earth Sci Technol & Res GESTAR 2 Baltimore MD 21228 USA Univ Iowa Dept Chem & Biochem Engn Iowa City IA 52242 USA China Univ Geosci Sch Geog & Informat Engn Hubei Key Lab Reg Ecol & Environm Change Wuhan 430074 Peoples R China NASA Atmospher Chem & Dynam Lab Goddard Space Flight Ctr Greenbelt MD 20771 USA NASA Climate & Radiat Lab Goddard Space Flight Ctr Greenbelt MD 20771 USA Colorado State Univ Cooperat Inst Res Atmosphere Ft Collins CO 80523 USA

This paper presents the Nighttime Ocean Aerosol Optical Depth (AOD) Retrieval algorithm (NOARA), an innovative method for deriving the oceanic AOD from the reflected moonlight observation of Day-Night Band (DNB) aboard the Visible Infrared Imaging Radiometer Suite (VIIRS) over ocean surfaces. Building upon the recent development of nighttime AOD retrievals for rural/wild areas over land, the NOARA introduces several advancements tailored for oceanic application: (a) the new dust and sea salt optical property models based on the AERONET observation;(b) the Cox-Munk bidirectional reflectance distribution function (BRDF) model that better represents the ocean surface reflectance;(c) the new internal cloud and dust masking schemes for the ocean areas. Case studies show that the nighttime AODs are in good consistency with multiple AOD measurements such as from AERONET and CALIOP. The algorithm fills the observational gap for a comprehensive understanding of the diurnal cycle of the dust transport over the ocean and has the potential to provide vital information to better constrain the chemical transport model.

关键词： Nighttime aerosol optical depth Visible band AOD Oceanic AOD Sahara dust plume Dust transport algorithm development VIIRS DNB Reflected moonlight Passive remote sensing over ocean

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Study of automatic optical inspection for golf logo quality

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JOURNAL OF ELECTRONIC IMAGING 2007年第3期16卷 033016.1-033016.12页

作者： Lin, Ku Chin Kun Shan Univ Dept Engn Mech Yun Kung City Tainan County Taiwan

Currently, inspection of the quality of a golf logo requires much time and manpower. There is a demanding need to reduce the escape rate. We present a preliminary but innovative study on development of an automatic optical inspection (AOI) system for golf logo quality This study includes the development of algorithms for logo matching, logo degradation measure, and logo alignment Logo contour features and spatial layout are implemented in the developed matching algorithm. The feasibility of the algorithm is assured regardless of the large variation in logo orientation. The proposed degradation measure is based on local window masking and coding. It is capable of detecting logo contours with small extrusion or intrusion defects. A positioning mechanism is specifically designated for automatic logo alignment. Good logo alignment is achieved through a proposed sequential control of ball orientation to enhance the discriminating power of the proposed degradation measure. Experiments conducted support the applicability of this study. A given example shows that the escape rate vanishes, but the false-alarm rate is 1.23%. A good balance between the escape rate and the false-alarm rate is achieved based on experiences or more experiments. For practical implementation, parallel computing is suggested to reduce the overall processing time. (c) 2007 SPIE and IS&T.

关键词： Inspection Optical inspection algorithm development Tolerancing Binary data Chemical elements Distortion Image segmentation Motion controllers Image retrieval

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