Computer-aided Design Methods Research Articles

General, robust, and efficient polyhedron intersection in the Interface Reconstruction Library

Intersecting a polyhedron with a half-space or another polyhedron is required in various fields, including computer graphics, computer-aided design, and many methods used in computational physics. Often, the polyhedra involved are complicated non-convex objects, and intersecting them constitutes a significant computational cost. To address this, we present a general, geometrically robust, and efficient polyhedron intersection algorithm based on the half-edge data structure and implemented in the open-source Interface Reconstruction Library. We then employ this algorithm in a novel graph-based approach to distribute the volume of a polyhedron over a computational mesh. To demonstrate their performance, the two methods are tested on randomly generated configurations. Compared to the open-source packages VOFTools and R3D, the polyhedron intersection algorithm shows superior speed over the range of convex and non-convex polyhedra tested. The volume distribution method also proves to be discretely conservative, even for meshes containing degenerate faces.

Predicting melting point of ionic liquids using QSPR approach: Literature review and new models

Quantitative structure–property relationships (QSPRs) for predicting melting point temperature (Tm) of ionic liquids (ILs) are reviewed and the new models are proposed by using the experimental data extracted from the literature for 953 salts. The models include both regression of Tm data and classification of the ILs with respect to their state of matter (liquid/solid) at T=300 K. A variety of machine learning algorithms is applied, including: partial least squares regression, stepwise multiple linear regression, and a number of common classifiers (k-nearest neighbors, naive Bayes, linear discriminant analysis, support vector machines). An effect of the molecular descriptors set as well as the computational level used for the ions’ geometry optimization is analyzed and followed in the final model selection protocol, which comprises all the standard steps of good practice of QSRP modeling, e.g. cross-validation, external validation, and the applicability domain analysis. Furthermore, as a key novelty, the robustness of the models is checked for different combining rules, defined as the averaging functions for obtaining the descriptors of ILs from those given for individual ions. The finally selected and recommended models are discussed in detail in terms of various statistics, as well as addressed to other methods reported in the literature. An effect of the chemical family of both cation and anion on the modeling performance is highlighted. Additionally, the predictions of both Tm and state of matter of more than 35,000 virtual cation–anion combinations are given in order to present the range of potential applications of the new methods in computer-aided molecular design of new ILs displaying demanded phase behavior.

Current Status of Digital Complete Dentures Technology

Fabrication of complete dentures (CDs) utilizing computer-aided design and computer-aided manufacturing (CAD/CAM) methods has attracted a lot of attention. The purpose of this paper was to summarize current knowledge about digital CDs and the relevant technology, and to present the application of the new technology in a dental geriatrics case. Initially, some of the challenges regarding digitization of the oral mucosa as a supporting surface of the CDs’ intaglio surface are listed. Next, a brief introduction of the CAD software capabilities regarding CDs is presented. The latest CAM additive and subtractive techniques for CDs are following. Subsequently, the consecutive steps for the construction of a digital CD as part of the prosthodontic treatment of a 90-year-old ambulative female patient are presented. Finally, some considerations about the digital workflow in CD manufacturing are discussed. In conclusion, the new digital technology has clear advantages; however, implementation requires careful planning. The digital workflow is applicable and versatile.

Inverse Design of Equivalent-Graded-Index Photonic-Crystal Fiber Based on Empirical Dispersion Formula

Equivalent-graded-index photonic-crystal fiber (EGI-PCF) is a modified photonic-crystal fiber (PCF) where the cladding is not required to be periodic. A radial gradient of the equivalent refractive index distribution provides extra freedom to efficiently tailor the dispersion of EGI-PCF. However, such additional complexity makes the manual fiber design much more challenging where the time consumption becomes too much to be afforded eventually. In this paper, we for the first time propose the method of computer-aided inverse fiber design (CAFD) based on empirical dispersion formula to circumvent this hurdle. We apply the differential evolution (DE) genetic algorithm to seek for the optimized EGI-PCF design with a target of specific dispersion profile. In the dispersion oriented EGI-PCF design, the use of empirical formula instead of numerical simulation (e.g., finite-element method) is proved to greatly reduce the run-time of CAFD and simplifies the fitness function evaluation as much as possible. We adopt our method and demonstrate a design of EGI-PCF with a near-zero ultra-flattened dispersion in the whole S+C+L band, which merely costs a few seconds of a laptop to return an optimized fiber design. Thus improvement of efficiency is about three orders of magnitude faster than any previous CAFD attempts as far as we learn. In the end, we use our method to explore an EGI-PCF design with a unique dispersion profile of all-normal dispersion-decreasing along the fiber length centered around 1 μm that plays a key role for the self-similar pulse evolution in a fiber laser/amplifier.

Computer-aided design method for random patterns of apparel fabrics

Random pattern is a pure digital art done by computer design, which can be widely used in clothing fabric pattern. This article introduces the method of using Photoshop general image processing software with external filter plug-in to design and produce random patterns for apparel fabrics.

Toward co-optimization of renewable fuel blend production and combustion in ultra-high efficiency SI engines

The shift from fossil to renewable fuels presents an opportunity to tailor a fuel’s molecular structure and composition to the needs of advanced internal combustion engine concepts, while simultaneously aiming for economic and sustainable fuel production. We have recently proposed a method for computer-aided design of tailor-made fuels that integrates aspects of both product and production pathway design. The present paper sets out to sequentially combine that method with experimental investigation on a single cylinder research engine and model-based early-stage process evaluation to create, validate, and benchmark a rationally designed multi-component biofuel for highly boosted spark-ignition engines. To this end, the computer-aided design approach is applied to a network of possible fuel components and their production pathways. The resulting optimal four-component fuel EBCC (50 mol% ethanol, 21 mol% 2-butanone, 15 mol% cyclopentane, and 14 mol% cyclopentanone) is analyzed with regard to combustion performance and estimated fuel production cost. Variations of both the indicated mean effective pressure and the relative air/fuel ratio were performed on an engine equipped with a compression ratio of 14.7. EBCC achieves indicated efficiencies that are significantly higher than those of RON 102 gasoline fuel and comparable to those of pure 2-butanone, an extremely knock-resistant fuel identified in a previous round of model-based fuel design. Furthermore, a strong reduction in engine-out soot emissions is observed compared to RON 102 gasoline. Early-stage process evaluation shows EBCC to have lower estimated fuel production costs than 2-butanone. Production costs of pure ethanol, however, are estimated to be even lower, mainly due to lower plant investment costs and a synthesis pathway that does not require hydrogen. The paper concludes with a brief perspective on further integration of the proposed sequential approach with the goal of co-optimizing the production and combustion of renewable fuel blends.

Research on the Application of Computer-aided Analysis System in the Concept of Visual Aesthetics in Graphic Design

The utilization of computer-aided analysis in graphic design mainly focuses on the design and testing of works, which helps to realize the effective use of visual aesthetics in graphic design works, and can maximize its effectiveness, so it has important research value. Based on this, this paper first analyzes the method of computer-aided graphic design, and then studies the parametric, modular and visual design in computer-aided graphic design, and finally gives the computer-aided analysis process of visual aesthetics of graphic design.

Combinational design of heterogeneous lattices with hybrid region stiffness tuning for additive manufacturing

Lattices with engineered properties are significant for engineering applications in the energy, aerospace, optics and medical sectors. Current additive manufacturing (AM) combined with computer-aided design (CAD) methods are not flexible enough to create multi-substructure lattices with locally varying geometrical features and mechanical properties. For example, if the struts of one substructure correspond spatially to the void of another substructure in the hybrid region, the resulting structure is disconnected there. When the number of substructures is large, such a problem becomes inevitable and intractable. Here we propose a new AM & CAD method integrating all the processes of designing a complex lattice structure, such as subspace partitioning, substructure rotation, filling in each subspace and connection, and hybrid region stiffness tuning. This method provides a general framework for designing heterogeneous lattice structures with disorder, gradient and hybrid features. Additionally, we numerically and experimentally investigate the effectiveness of our hybrid region stiffness tuning method. Using this new method, the problem of low volume fraction or disconnection in the hybrid region in multi-substructure lattices is overcome, and the resulting structures can be generated for analysis or fabrication by any suitable AM technique.

Cover, Content, and Editorial Note from J Mol Docking Vol. 1 No. 1 June 2021

Assalamu’alaikum Wr. Wb.Alhamdulillahirabbil ‘alamin. After a long wait for almost 1 year from the first planned, finally, the new scientific journal of the Department of Pharmacy Universitas Muhammadiyah Palangkaraya can be published. This scientific journal was named the Journal of Molecular Docking (J Mol Docking), inspired by one of the most popular in silico methods in computer-aided drug design. Journal of Molecular Docking published every 6 months (2 issues/year) every June and December.This edition contains five articles consisting of writings from four countries including Indonesia, India, Bulgaria, and Egypt. The authors come from several institutions, including Bio Search Research Institution, Sekolah Tinggi Farmasi Muhammadiyah Tangerang, Sri Ramachandra Institute of Higher Education and Research, Siddha Central Research Institute – Central Council for Research in Siddha, Chhattisgarh Swami Vivekanand Technical University, Universitas Mataram, and Medical University – Sofia.Editorial boards are fully aware that there is still room for improvement in this edition, hence with all humility willing to accept constructive suggestions and feedback for improvements to the publication for the next editions. The editorial board would like to thank all editors and reviewers, and contributors of the scientific articles who have provided the repertoire in this issue. We hope that all parties, especially the contributors of the articles, could re-participate for publication in the next edition in December 2021.Wassalamu’alaikum Wr. Wb.

Comparing Player Skill, Game Variants, and Learning Rates Using Survival Analysis

Game designers can use computer-aided game design methods to quantitatively compare player skill levels, different game variants, and learning rates, for the purpose of modeling how players will likely experience a game. We use Monte-Carlo simulation, hazard functions, and survival analysis to show how difficulty will quantitatively change throughout a game level as we vary skill, game parameters, and learning rates. We give a mathematical overview of survival analysis, present empirical data analyses of our player models for each game variant, and provide theoretical probability distributions for each game. This analysis shows the quantitative reasons why balancing a game for a wide range of player skill can be difficult; our player modeling provides tools for tuning this game balance. We also analyze the score distribution of over 175 million play sessions of a popular online Flappy Bird variant to demonstrate how learning effects can impact scores, implying that learning is crucial aspect of player modeling.

Ionic liquid-based in situ product removal design exemplified for an acetone-butanol-ethanol fermentation.

Selecting an appropriate separation technique is essential for the application of in situ product removal (ISPR) technology in biological processes. In this work, a three-stage systematic design method is proposed as a guide to integrate ionic liquid (IL)-based separation techniques into ISPR. This design method combines the selection of a suitable ISPR processing scheme, the optimal design of an IL-based liquid-liquid extraction (LLE) system followed by process simulation and evaluation. As a proof of concept, results for a conventional acetone-butanol-ethanol fermentation are presented (40,000 ton/year butanol production). In this application, ILs tetradecyl(trihexyl)phosphonium tetracyanoborate ([TDPh][TCB]) and tetraoctylammonium 2-methyl-1-naphthoate ([TOA] [MNaph]) are identified as the optimal solvents from computer-aided IL design (CAILD) method and reported experimental data, respectively. The dynamic simulation results for the fermentation process show that, the productivity of IL-based in situ (fed-batch) process and in situ (batch) process is around 2.7 and 1.8fold that of base case. Additionally, the IL-based in situ (fed-batch) process and in situ (batch) process also have significant energy savings (79.6% and 77.6%) when compared to the base case.

Analysis of calculations when creating a theoretical drawing of a tug by the interpolation method

The development of a theoretical drawing by manual methods is notable for considerable laboriousness, in this regard, the use of methods that significantly reduce the development time and increase its quality is relevant. In this work, a comparative analysis of methods for obtaining ordinates of a theoretical drawing is carried out. The existing methods of computer-aided design and methods of forming a theoretical drawing are considered: classical, interpolation, affine transformation method, modular method. The process of development of the surface of the tug by the interpolation method is shown, the substantiation of its application is carried out. On the basis of the developed model, a program for calculating the ordinates of the theoretical drawing of tugboats was developed. The results of the software package operation are presented, namely, the ordinates of the theoretical drawing of the tugboat and the hull of the theoretical drawing, as well as the analysis of the calculation accuracy. The adopted approach to the development of the ship's surface can significantly reduce the time and cost of design work on the development of the ship's surface, can be used for its further automation and use as scientific, industrial and educational purposes.

Computer-Aided Design Method of Parametric Model for Landscape Planning

Computer-Aided Design and Applications is an international journal on the applications of CAD and CAM. It publishes papers in the general domain of CAD plus in emerging fields like bio-CAD, nano-CAD, soft-CAD, garment-CAD, PLM, PDM, CAD data mining, CAD and the internet, CAD education, genetic algorithms and CAD engines. The journal is aimed at all developers and users of CAD technology to ptovide CAD solutions for various stages of design and manufacturing. The journal publishes all about Computer-Aided Design and Computer-Aided technologies.

Research on Artificial Intelligence Interaction in Computer-Aided Arts and Crafts

Background. With the continuous maturity of computer software and hardware technology, the theory and method of computer-aided art design have developed rapidly. Objective. Applying artificial intelligence theory to computer-aided process art design is one of the newly developed research hotspots, and it is also the development trend of industrial design modernization. Methods. On the one hand, it can transplant the research results in the field of artificial intelligence into computer-aided art design, and on the other hand, it expands the application field of artificial intelligence, so that the two can be perfectly combined to promote common development. Results. With the development of artificial intelligence technology, computer art has gradually become a very active field, and a large number of computer art works are available every year. Conclusions. This paper briefly describes the basic concepts of computer-aided art design and artificial intelligence and discusses the application of artificial intelligence in computer-aided art design.

Improving virtual screening results with MM/GBSA and MM/PBSA rescoring.

Virtual screening (VS) based on molecular docking is one of the most useful methods in computer-aided drug design. By allowing to identify computationally putative ligands binding to the proteins of interest, VS dramatically reduces the time and expense of the development of novel therapeutics. Among the limitations of the VS approaches is the low accuracy of scoring functions implemented in docking methods for assessing binding affinity. Many such scoring functions are developed for rapid, high-throughput evaluation of binding energy of multiple conformations generated by a searching algorithm. The methods for more rigorous calculation of binding affinity calculation are generally time-consuming. Even so, in many studies more accurate methods were used for rescoring of the final poses and false-positive hits evaluation. We performed VS for three benchmark sets and used energy minimization with MM/PB(GB)SA methods (molecular mechanics energies combined with the Poisson-Boltzmann or generalized Born and surface area) to rescore binding affinities. The comparison of the area under the curve (AUC), enrichment factor (EF), and Boltzmann-enhanced discrimination of receiver operating characteristics (BEDROC) showed essential improvements in the binding energy prediction after the rescoring. Finally, we provide a program for minimization and rescoring VS results based on freely available AmberTools. The code requires just the final binding poses of the ligand as the input and can be used with any docking program.

Resourceful Fast Discrete Hartley Transform to Replace Discrete Fourier Transform with Implementation of DHT Algorithm for VLSI Architecture

Discrete Fourier Transform (DFT) is used in a range of digital signal processing applications, such as signal and image compression systems, filter banks, signal representation or harmonic analysis. The Discrete Hartley Transform (DHT) can be used to effectively replace the DFT when the input sequence is real. This paper introduces and applies the Discrete Hartley Transform (DHT) algorithm, which is well suited to the VLSI architecture. The purpose of using the DHT algorithm is to reduce the complexity of the VLSI architecture. With the introduction of VLSI architectures, 100,000 transistors can be mounted on a single chip. For manufacturers, the verification of these circuits on breadboards is not feasible. Computer-aided design methods have now come into being, but programmers also had to make connections manually at the gate level. Subsequently, Hardware Description Language (HDL) such as Verilog and VHDL came into being. With the integration of the DHT algorithm and its execution, Verilog authors have worked to reduce the complexity of the VLSI circuits in this article. With reduced complexity, the power consumption is reduced and thus the area is therefore reduced. DHT is an algorithm for the Radix-2. It is especially useful for image and signal processing. The DHT algorithm for length N=8 is introduced here.

Advances in Applying Computer-Aided Drug Design for Neurodegenerative Diseases.

Neurodegenerative diseases (NDs) including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and Huntington’s disease are incurable and affect millions of people worldwide. The development of treatments for this unmet clinical need is a major global research challenge. Computer-aided drug design (CADD) methods minimize the huge number of ligands that could be screened in biological assays, reducing the cost, time, and effort required to develop new drugs. In this review, we provide an introduction to CADD and examine the progress in applying CADD and other molecular docking studies to NDs. We provide an updated overview of potential therapeutic targets for various NDs and discuss some of the advantages and disadvantages of these tools.

Energy-efficient recovery of tetrahydrofuran and ethyl acetate by triple-column extractive distillation: entrainer design and process optimization

An energy-efficient triple-column extractive distillation process is developed for recovering tetrahydrofuran and ethyl acetate from industrial effluent. The process development follows a rigorous hierarchical design procedure that involves entrainer design, thermodynamic analysis, process design and optimization, and heat integration. The computer-aided molecular design method is firstly used to find promising entrainer candidates and the best one is determined via rigorous thermodynamic analysis. Subsequently, the direct and indirect triple-column extractive distillation processes are proposed in the conceptual design step. These two extractive distillation processes are then optimized by employing an improved genetic algorithm. Finally, heat integration is performed to further reduce the process energy consumption. The results indicate that the indirect extractive distillation process with heat integration shows the highest performance in terms of the process economics.

Design, synthesis and biological evaluation of anilide (dicarboxylic acid) shikonin esters as antitumor agents through targeting PI3K/Akt/mTOR signaling pathway

Triple-negative breast cancer (TNBC) has an unfavorable prognosis attribute to its low differentiation, rapid proliferation and high distant metastasis rate. PI3K/Akt/mTOR as an intracellular signaling pathway plays a key role in the cell proliferation, migration, invasion, metabolism and regeneration. In this work, we designed and synthesized a series of anilide (dicarboxylic acid) shikonin esters targeting PI3K/Akt/mTOR signaling pathway, and assessed their antitumor effects. Through three rounds of screening by computer-aided drug design method (CADD), we preliminarily obtained sixteen novel anilide (dicarboxylic acid) shikonin esters and identified them as excellent compounds. CCK-8 assay results demonstrated that compound M9 exhibited better antiproliferative activities against MDA-MB-231, A549 and HeLa cell lines than shikonin (SK), especially for MDA-MB-231 (M9: IC50 = 4.52 ± 0.28 μM; SK: IC50 = 7.62 ± 0.26 μM). Moreover, the antiproliferative activity of M9 was better than that of paclitaxel. Further pharmacological studies showed that M9 could induce apoptosis of MDA-MB-231 cells and arrest the cell cycle in G2/M phase. M9 also inhibited the migration of MDA-MB-231 cells by inhibiting Wnt/β-catenin signaling pathway. In addition, western blot results showed that M9 could inhibit cell proliferation and migration by down-regulating PI3K/Akt/mTOR signaling pathway. Finally, a three-dimensional quantitative structure–activity relationship (3D-QSAR) model was also constructed to provide a basis for further development of shikonin derivatives as potential antitumor drugs through structure–activity relationship analysis. To sum up, M9 could be a potential candidate for TNBC therapy.

Computer-Aided Ionic Liquid Design and Experimental Validation for Benzene–Cyclohexane Separation

For the purpose of designing ionic liquid (IL) solvents for the extractive separation of benzene/cyclohexane at 298.15 K, a computer-aided ionic liquid design (CAILD) method is developed. The UNIFAC-IL model is used to calculate the thermodynamic properties, while the group contribution (GC)-based methods are employed to estimate the physical properties and toxicity. A mixed-integer nonlinear programming (MINLP) problem is formulated, and the top five IL solvents are obtained by the BONMIN algorithm. One of the designed ILs [COC2MIM][Tf2N] (1-(2-methoxyethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) is selected to perform the liquid–liquid extraction (LLE) experiment, and the distribution ratio and selectivity at 0.1 molar concentration of benzene in the raffinate phase are 1.20 and 17.10, respectively. The comparison with other solvents shows that the designed IL not only has an excellent separation performance but also favorable physical and environmental properties. After regressing the parameters for the NRTL model, the process simulation using the designed IL is developed by Aspen Plus, and the results are compared with that of the benchmark organic solvent sulfolane. The IL-based process needs 32475.1 kg/h of solvent and 1283 kW of heat duty, while the sulfolane-based process uses 43998.5 kg/h of solvent and 6296 kW of heat duty. These results demonstrating [COC2MIM][Tf2N] is a promising alternative to conventional solvents for the extractive separation of benzene/cyclohexane.