Simplification Methodology Research Articles

Chroma Intra Prediction With Lightweight Attention-Based Neural Networks

Neural networks can be successfully used for cross-component prediction in video coding. In particular, attention-based architectures are suitable for chroma intra prediction using luma information because of their capability to model relations between different channels. However, the complexity of such methods is still very high and should be further reduced, especially for decoding. In this paper, a cost-effective attention-based neural network is designed for chroma intra prediction. Moreover, with the goal of further improving coding performance, a novel approach is introduced to utilize more boundary information effectively. In addition to improving prediction, a simplification methodology is also proposed to reduce inference complexity by simplifying convolutions. The proposed schemes are integrated into H.266/Versatile Video Coding (VVC) pipeline, and only one additional binary block-level syntax flag is introduced to indicate whether a given block makes use of the proposed method. Experimental results demonstrate that the proposed scheme achieves up to -0.46%/-2.29%/-2.17% BD-rate reduction on Y/Cb/Cr components, respectively, compared with H.266/VVC anchor. Reductions in the encoding and decoding complexity of up to 22% and 61%, respectively, are achieved by the proposed scheme with respect to the previous attention-based chroma intra prediction method while maintaining coding performance.

The application of cycle merging and an extension of a fatigue spectrum simplification methodology from unidirectional to woven composite materials

This work details the application of cycle merging on a fatigue spectrum applied to a unidirectional specimen. The specimen design has previously been the subject of a ground up approach to simplify a loading spectrum using truncation. The extension of this methodology to a woven specimen is also detailed with truncation demonstrating its ability to remove low damaging cycles, achieving a reduction of up to 74%. The combined application of truncation and cycle merging to achieve a 95% load spectrum reduction is also presented, with reduced spectra demonstrating similar experimental scatter in fatigue tests to the original uncompressed load spectrum.

Toward Simplified Physics-Based Memristor Modeling of Valence Change Mechanism Devices

Memristors are promising nanoelectronic devices for the implementation of future AI-driven sensor-processor electronic systems, which are essential for the ongoing digitalization of our world. Accurate and computationally cost-effective models for the manufactured memristors are essential for the design of such systems, especially for the simulation of large circuits. In this brief we address the simplification of the JART memristor model, a generic physics-based model of Valence Change Mechanism (VCM) memristors which accurately describes the dynamic behavior of fabricated memristor devices. Furthermore, the proposed model and simplification methodology have the potential to capture the dynamics of a wide range of memristor devices. Importantly, the implicit description of the current through the memristor is replaced by an explicit mathematical relationship. The proper reproduction of memristor dynamics, verified by applying the system-theoretic Dynamic Route Map (DRM) graphical analysis tool, applicable to first-order systems, can be observed through the proposed simplified model and enables the time-efficient simulation of large arrays of VCM devices.

Integration of design and NMPC-based control for chemical processes under uncertainty: An MPCC-based framework

The use of nonlinear model predictive control (NMPC) for the integration of design and control remains as an open area of research. When NMPC is incorporated into the framework for design and control, this results into a bilevel problem formulation. The search of a solution for a bilevel problem is often carried out with the implementation of systematic iterative methodologies. In this work, we implement the classical KKT transformation strategy to transform the original bilevel problem for simultaneous design and NMPC-based control into a single-level dynamic optimization problem. This single-level formulation is referred to as a mathematical program with complementarity constraints (MPCC). Violations to constraint qualifications (CQs) are avoided through the implementation of several reformulation techniques. This facilitates the convergence of the MPCC for optimal design and control. The use of an MPCC-based formulation allows to fully incorporate the NMPC’s necessary conditions for optimality into the design problem as a set of algebraic constraints. Accordingly, the MPCC is solved as a conventional NLP, i.e., we avoid the use of decomposition or simplification methodologies for the solution of the bilevel problem. This guarantees optimality in the solution for integrated design and NMPC-based control. This strategy was implemented in three case studies involving small, medium-scale, and highly nonlinear systems to demonstrate the application of MPCCs for design and NMPC-based control under process disturbances and uncertainty.

Optimization of low carbon fuels operation on a CI engine under a simplified driving cycle for transportation de-fossilization

The study of internal combustion engines, and their associated energy conversion processes, is currently focused on targeting the reduction of pollutant emissions while maintaining or improving efficiency and fuel consumption. The research of alternative fuels, in particular low carbon fuels (LCF), seems to be a promising strategy for solving this problem. However, the characterization of a fuel with properties different than those of diesel requires numerous tests and resources to prove the viability of the substitution for another alternative. In Europe, for a vehicle to be homologated the World harmonized Light vehicles Test Cycle (WLTC) must be complied with. This cycle requires transient tests, that performed with a fuel for which an engine calibration is not yet existent would be difficult and could hinder the evaluation of the potential of a given fuel. This study proposes a cycle simplification methodology that seeks to reduce the driving cycle to a discrete set of stationary conditions, for which each operational calibration can be optimized. The optimization methodology is based on statistical analysis and modelling, and is presented to select the most desirable operating condition that can be reached using an LCF. For each testing point optimization NOx, soot, brake efficiency and fuel consumption are used as targets. Finally, the calibrated operating conditions are applied within the simplified cycle to assess the homologation potential of the studied fuel, as well as the equivalent CO2 emissions under the criteria of a well-to-wheel analysis (WTW).

Experimental evaluation of a mooring system simplification methodology for reducing mooring lines in a VLFS model testing at a moderate water depth

The scale model experiment for typical offshore floating structures with increasingly excessive mooring lines is usually complex and difficult to set up, which often results in low reliability of the experimental results. In the previous paper, Liang et al. (2019) proposed a mooring system simplification methodology for the scale model experiment based on the equivalent of the vessel/mooring coupled dynamics for vessel with original and simplified mooring systems and demonstrated its effectiveness by numerical studies In this paper, the feasibility of the mooring system simplification methodology is further evaluated by a model test for a very large floating structure’s (VLFS’s) mooring system comprising 20 mooring chains. A 10 chains simplified mooring system is obtained with the correlation coefficients of coupled vessel/mooring dynamics larger than 0.9. Thereafter, the equivalence of the original and simplified mooring systems is validated by performing the decay test, white noise test, regular and irregular wave tests. The coincidence of the model test results, including natural period, damping coefficient, response amplitude operator (RAO), motion power spectral density and motion time series of the VLFS model, confirms the equivalence of the simplified mooring system with the original mooring system and indicates that the mooring system simplification methodology is effective in designing the simplified mooring system to replace the original mooring system in a scale model experiment.

Static and Dynamic Partitions of Inequalities: A Unified Methodology for Supervisor Simplification

In the context of automated manufacturing systems, supervisor simplification is drawing increasing attention. As a special class of state specifications, generalized mutual exclusion constraints (GMECs) are a typical kind of supervisory control of Petri nets. In this note, we first propose static and dynamic partitions to reduce the size of supervisor by partitioning inequalities, i.e., GMECs, into redundant and necessary ones. The former considers the specifications themselves and exhibits higher efficiency; while the latter takes into account both specifications and reachable markings and achieves more economical supervisors. In an incremental manner, we develop Type I supervisor simplification method which has a compromised efficiency and complexity. In an integrated manner, we propose Type II supervisor simplification method that further improves efficiency and eases computational complexity. All techniques proposed in this note can be realized in an algebraic manner. Examples are presented for the sake of illustration as well as demonstration.

Simplification of mooring line number for model testing based on equivalent of vessel/mooring coupled dynamics

To decrease the complexity of experimental setup that often results in low reliability of the experimental results for typical offshore floating structures with increasingly excessive mooring lines, a mooring line number simplification methodology is proposed based on equivalent of the vessel/mooring coupled dynamics for vessel with original and simplified mooring systems. The Non-dominated Sorting Genetic Algorithms-II (NSGA-II) is adopted to achieve the static restoring forces equivalent, where the line length, axial stiffness and submerged mass of the simplified mooring system are obtained. The line diameter is then determined based on dynamic restoring forces equivalent when the mooring system is exerted by forced oscillations. Using correlation coefficients, the vessel/mooring coupled dynamics of vessel with original and simplified mooring systems are compared to determine the optimal simplified mooring system. The feasibility of the proposed methodology is demonstrated by an application for a VLFS’s mooring system comprising 20 mooring lines. Two simplified mooring systems are obtained with the correlation coefficients of coupled vessel/mooring dynamics lager than 0.97. It can be concluded that the proposed method can be used as a useful tool to guide mooring line number simplification for model testing.

Critical Response of Nonlinear Base-Isolated Building Considering Soil-Structure Interaction Under Double Impulse as Substitute for Near-Fault Ground Motion

The critical nonlinear response considering soil-structure interaction is investigated for a base-isolated building under a double impulse as a substitute for near-fault earthquake ground motions. The complicated model of the nonlinear base-isolated building considering soil-structure interaction is first modeled as a two-degree-of-freedom (2DOF) system (SDOF superstructure and base-isolation story) on a swaying-rocking spring-dashpot system. Then the 2DOF system on a swaying-rocking spring-dashpot system is transformed into an SDOF system on a swaying-rocking spring-dashpot system by neglecting the mass on the base-isolation story. Finally the SDOF system on a swaying-rocking spring-dashpot system is further transformed into an SDOF system by neglecting the mass and moment of inertia of the base mat. Since an explicit expression had been derived in the previous paper on the maximum elastic-plastic response of an SDOF damped bilinear hysteretic structure subjected to the ‘critical double impulse input’ causing the maximum response for variable interval of impulses with the input level kept constant, this expression is applied to the finally transformed SDOF system. The transformation of structural viscous damping in different elements is another new aspect in this paper. The reliability and accuracy of the proposed simplification methodology are investigated by comparing with the results by the time-history response analysis under the critical double impulse and the one-cycle sine wave as a representative of the main part of the near-fault earthquake ground motion.

An Analysis of Reconstruction Algorithms Applied to 3D Building Modeling

Objectives: The process of reconstructing a city cannot be fully automated. More human intervention is required to achieve high quality mass modeling. Our objectives are to provide a guide for the 3D graphic designers and 3D modelers in developing 3D building models. Methods: We present an up-to-date survey of the reconstruction algorithms which are further classified as point cloud based reconstruction methods and structure-aware shape reconstruction methods. We introduce various existing 3D reconstruction techniques and have compared those techniques based on shape simplification, surface completion and shape modeling methodologies. Findings: We have identified the pipeline process and technical issues encountered in each phase of the reconstruction process from a given image layout. As stated, the inverse procedural reconstruction approaches are best oriented towards the reconstruction of buildings from a given input 2D image. Also, there is a lack of systems that are capable of generating procedural rules from user interaction. Improvements: We propose a new 3D reconstruction methodology and novel framework that combines component based structure capturing and rule based modeling techniques that would best be suitable for 3D building modeling, resembling the real world buildings in future systems.

Supervisor Simplification in FMSs: Comparative Studies and New Results Using Petri Nets

Modern complex systems require intensive application of sophisticated supervisors. Structural simplification techniques are one of the fundamental researches in the context of flexible manufacturing systems (FMSs). They can reduce implementation cost, mitigate fabrication complexity, and improve reliability. Several typical methods have been developed along this direction. In order to thoroughly explore their effectiveness and performance, we not only conduct a comparison investigation but also develop some new theoretical results. Several analytical results and performance measures are proposed for their qualitative and quantitative comparison. Our approach can assist researchers and practitioners to better comprehend the inherent mechanisms and relative merits of these simplification methodologies as well as their applicability in FMSs. This paper is motivated by FMSs’ control; however, it is also applicable to other systems with discrete event controllers.

Symbolic factorization methodology for multistage amplifier transfer functions

SummaryIn this paper, we discuss a symbolic simplification methodology to derive approximated factorized forms of the transfer function of multistage amplifiers in the complex frequency domain. The developed approach is useful for hand calculation and is also suitable to be implemented in symbolic computer‐aided design tools. Although the proposed methodology is mainly intended for the analysis and design of operational transconductance amplifiers, it can straightforwardly be applied to the small‐signal analysis of any analog linear circuit. Design examples are provided to verify the effectiveness of the proposed approach implemented through a Matlab function. Copyright © 2015 John Wiley & Sons, Ltd.

Heating and Cooling Loads in High Performance Construction Systems- Will Climate Change Alter Design Decisions?

Climate change and its consequences are of great concern. Buildings can be affected by climate change in different ways, such as changes in energy needs and thermal comfort. However, the challenge is to quantify and assess the uncertainties involved in future climate data as well as the relevant adoption strategies. The aim of this paper is to demonstrate potential energy consumption changes in high performance building construction systems in a changing climate. In this paper, current and future weather data of three time slices of 2020, 2050 and 2080 were used to simulate the performance of a simple building in Manchester and London using DesignBuilder software which employs Energy Plus as its calculation engine. Five of the most commonly used and high performance construction systems were examined in terms of energy consumption in this model and results are given. In general, this paper provides a useful methodology for simplification in design decision-making for current and future UK housing. It is observed that future climate scenarios do not have major effects in qualitative comparisons of construction systems.

SimpliFly: A Methodology for Simplification and Thematic Enhancement of Trajectories.

Movement data sets collected using today's advanced tracking devices consist of complex trajectories in terms of length, shape, and number of recorded positions. Multiple additional attributes characterizing the movement and its environment are often also included making the level of complexity even higher. Simplification of trajectories can improve the visibility of relevant information by reducing less relevant details while maintaining important movement patterns. We propose a systematic stepwise methodology for simplifying and thematically enhancing trajectories in order to support their visual analysis. The methodology is applied iteratively and is composed of: (a) a simplification step applied to reduce the morphological complexity of the trajectories, (b) a thematic enhancement step which aims at accentuating patterns of movement, and (c) the representation and interactive exploration of the results in order to make interpretations of the findings and further refinement to the simplification and enhancement process. We illustrate our methodology through an analysis example of two different types of tracks, aircraft and pedestrian movement.

An evolutionary-based methodology for symbolic simplification of analog circuits using genetic algorithm and simulated annealing

In this paper, an evolutionary-based multi-objective criterion is introduced for simplified symbolic small-signal analysis of analog circuits containing MOSFETs. After circuit analysis via modified nodal analysis technique, the derived exact symbolic transfer function of the circuit behavior is automatically simplified. In contrast to traditional simplification criteria, the main objective of our criterion is to control the final simplification error rate. The proposed simplification methodology can be performed by such optimization algorithms as local-search algorithms, heuristic algorithms, swarm intelligence algorithms, etc. In this paper, a hybrid algorithm based on genetic algorithm and simulated annealing is applied to validate the proposed methodology. It is remarkable that all steps including netlist text processing, symbolic analysis, post-processing, simplification, and numerical analysis are consecutively derived in an m-file MATLAB program. The proposed methodology was successfully tested on three analog circuits, and the numerical results were compared with HSPICE.

Towards energy performance evaluation in early stage building design: A simplification methodology for commercial building models

The paper analyses the benefits of the application of energy analysis in the early-stage building design, in particular for large commercial buildings. The research highlights the barriers that prevent this early integration and finally proposes the development of a methodology tailored around the optimization of energy efficiency during early-stage design. In general, the research aims to identify (a) the accuracy obtainable through progressive simplifications of the building model, (b) the most significant building parameters with respect to the model result accuracy and (c) the maximum number of simplifications able to ensure the respect of time requirements dictated by early-stage building design and to maintain an acceptable level of correctness. Here, as detailed example of simplification process, a case study of a large multi-storey office building is modelled starting with a previous detailed simulation performed through EnergyPlus and Openstudio software. The detailed model is then analyzed and progressively simplified. At each progressive simplification step, a comparison with the detailed results is given in terms of building energy needs and power curves of the system. The analysis is performed based on three different system hypotheses: a single-zone system and a variable air volume system with and without humidity control. The quantitative differences between detailed and simplified model are analyzed to determine the quality of the results of the simplified model.

Prediction of residual stresses in a dissimilar metal welded pipe with considering cladding, buttering and post weld heat treatment

Dissimilar metal weld joints are widely used in the nuclear power plants to connect the ferritic steel components and the austenitic steel piping systems. Because the manufacturing processes are considerably complicated, it is difficult to accurately predict residual stresses in dissimilar metal weld joints by numerical simulation technology. In this study, a simplification methodology has been developed to compute residual stresses in a dissimilar metal pipe joint with considering cladding, buttering, post weld heat treatment (heat treatment after cladding and buttering) and multi-pass welding using a united fashion. The computational procedure based on thermal elastic plastic finite element method is used to simulate the thermo-mechanical behaviors. With using this computational procedure, the variations of stress status at each manufacturing stage are investigated and the influences of cladding, buttering and post weld heat treatment on the final residual stresses after welding are also clarified. In addition, the simulation results are compared with the measured data and the usefulness of present method is verified.

Application of a vortex tracking method to the piston-like behaviour in a semi-entrained vertical gap

Near resonance the piston mode amplitude in semi-entrained volumes of fluid such as in moonpools or in between a ship and a terminal may become large relative to the level of excitation. Linear theory is known to over-predict the fluid response in these types of systems significantly, suffering from the lack of damping whose only manifestation is radiated waves. In reality, however, viscous effects may act as damping and nonlinear effects associated with the free surface conditions may cause transfer of energy between the different modes. In the present work, which is within the framework of potential theory, a fully nonlinear numerical wavetank based on Green’s 2nd identity coupled with an inviscid vortex tracking method is applied to the moonpool problem. The paper presents a methodology for perpetual simplification of the free shear layer as the system undergoes near sinusoidal motion in order to reach steady state. This is practically impossible without such simplifications due to the otherwise exceedingly complex wake structures evolving only after the first one or two periods. Also the in- and out-flow of the boundary layers are modelled. The results are compared to experiments. In the investigated cases models of rectangular shape with sharp corners provide well-defined separation points, and such sharp corners are in practice introduced e.g. by bilge keels. It is found that: (1) The damping effect associated with the nonlinear free surface conditions are of minor importance, (2) the effect of the in- and out-flow of the boundary layer is negligible to all practical purposes, whereas (3) the flow separation explains the major part of the discrepancy between the measured response and that estimated by linear theory.

Design and synthesis of diketopiperazine and acyclic analogs related to the caprazamycins and liposidomycins as potential antibacterial agents

A systematic simplification methodology of a class of 6′- N-alkyl-5′- O-aminoribosyl-glycyluridine antibiotics was shown to produce potential antibacterial agents having a novel mechanism of action. Diketopiperazines and acyclic analogs of the caprazamycins (CPZs) and liposidomycins (LPMs) were efficiently synthesized, and their antibacterial activity was evaluated. The diketopiperazine analog 11a and the acyclic analogs 12a and 16a having a palmitoyl group as a lipophilic side chain exhibited moderate antibacterial activities with MICs of 12.5–50 μg/mL. This approach could provide ready access to a range of analogs for the development of potential antibacterial agents.

Symbolic analysis of large analog integrated circuits: the numerical reference generation problem

Symbolic analysis potentialities for gaining circuit insight and for efficient repetitive evaluations have been limited by the exponential increase of formula complexity with the circuit size. This drawback has begun to be solved by the introduction of simplification before and during generation techniques. An appropriate error control in both involves the generation of a numerical reference, which implies the calculation of network functions in the complex frequency variable. The polynomial interpolation method, traditionally used for this task, is analyzed in detail, its limitations for large circuit analysis are pointed out, and an adaptive scaling mechanism is proposed to meet the efficiency and accuracy requirements imposed by the new simplification methodologies.