Parametric Diagram Research Articles

Interactive Tree Decomposition Tool for Reducing System Analysis Complexity

We present a graphical tool for the calculation of treewidth, a metric on the parametric structure of a system that is intimately tied to the complexity of system analysis. For many graphically describable systems, such as systems of parametric equations, as in a SysML Parametric Diagram, or Bayesian networks or even mind maps and writing term papers, analysis of the system is exponential in treewidth and linear in system size. A tool facilitating comprehensive analysis can serve to bring competitive advantage to a systems engineering workflow by reducing costly unanticipated behaviors. Furthermore, a byproduct of computing treewidth is a framework for enumerating computationally compatible distributed algorithms.In this paper, we pose this NP-complete problem from the perspective of finding satisficing solutions, exposing choices that can influence the complexity of the resulting system to the designer. A designer can contribute two important things to the structure of the system: a visual intuition about the relationships between the underlying objects and the ability to change the relationships themselves at design time to reduce analysis complexity. Having a visual tool that provides instant feedback will help designers achieve an intuitive grasp of the relationship between design decisions and system complexity. As complexity is the root of almost every systems engineering problem, and also something not easily understood, incorporating complexity analysis into a design process should improve resulting system designs.The tool uses a randomized, anytime algorithm for interactive optimization of treewidth. It presents a sequence of choices to a designer and incrementally lowers an upper bound on system treewidth over time. This algorithm is novel, as few algorithms are targeted at interactivity with a human user. We present a number of simple examples for using the tool. We show how our tool helps to decompose some example systems, including a quadrotor optimization, a sensor network optimization, a Bayesian network, and a mind map.

Bimodal Surface Ligand Engineering: The Key to Tunable Nanocomposites

Tuning the dispersion of inorganic nanoparticles within organic matrices is critical to optimizing polymer nanocomposite properties and is intrinsically difficult due to their strong enthalpic incompatibility. Conventional attempts to use polymer brushes to control nanoparticle dispersion are challenged by the need for high graft density to reduce particle core-core attractions and the need for low graft density to reduce the entropic penalty for matrix penetration into the brush. We validated a parametric phase diagram previously reported by Pryamtisyn et al. (Pryamtisyn, V.; Ganesan, V.; Panagiotopoulos, A. Z.; Liu, H.; Kumar, S. K. Modeling the Anisotropic Self-Assembly of Spherical Polymer-Grafted Nanoparticles. J. Chem. Phys.2009, 131, 221102) for predicting dispersion of monomodal-polymer-brush-modified nanoparticles in polymer matrices. The theoretical calculation successfully predicted the experimental observation that the monomodal-poly(dimethyl siloxane) (PDMS)-brush-grafted TiO(2) nanoparticles can only be well dispersed within a small molecular weight silicone matrix. We further extended the parametric phase diagram to analyze the dispersion behavior of bimodal-PDMS-brush-grafted particles, which is also in good agreement with experimental results. Utilizing a bimodal grafted polymer brush design, with densely grafted short brushes to shield particle surfaces and sparsely grafted long brushes that favor the entanglement with matrix chains, we dispersed TiO(2) nanoparticles in high molecular weight commercial silicone matrices and successfully prepared thick (about 5 mm) transparent high-refractive-index TiO(2)/silicone nanocomposites.

Optical performance monitoring using the novel parametric asynchronous eye diagram

In this paper we present a novel technique, based in what we have called Parametric Asynchronous Eye Diagram (PAED). We have used a simulation scheme, which includes a differentiator and an Artificial Neural Network to monitor simultaneously several impairments such as Chromatic Dispersion, Polarization Mode Dispersion and Optical Signal to Noise Ratio. A number of modulation formats, including NRZ, RZ and QPSK is used in the computation of results. This paper also demonstrates the effectiveness of this technique in monitoring with one single device, mixed traffic, with different bit rates and On-Off Keying (OOK) modulation formats traveling through the network.

2110 ModelicaとSysMLの統合による企画設計支援(D&Sコンテスト口頭発表)

For purpose of supporting initial early design stage, a physical modelling language named Modelica is proposed. The Modelica is used in the multi-domain simulation from the conceptual and functional design stage. On the other hand, for the purpose of designing complex systems such as like automobile or medical equipment which have large software and much behaviour, a System Modelling Language SysML is proposed in order to capture the customer requirement and reduce the behavioural and software development time. One of the weak points of Modelica is poor description ability for requirement analysis approach because of lack of representing complex combination of states actions such as like complex software. Also, SysML has some weak point that it is hard to understand for physical engineer because lack of representation ability of differential equation and algebraic equation. A parametric diagram, which is newly added when SysML is proposed from UML (Unified Modelling Language), is only able to describe such physical phenomena. This weak point of SysML can be recognized as the strong point of Modelica. Hence, this paper proposes an integrated design support system which includes SysML and Modelica via proposing integrated modelling methodology. The requirement definition is developed using component behaviour and actions in SysML, and the physical modelling is developed by physical properties on component attribute in Modelica. By this integration, the physical and software simulation can be done from early design stage.

Noise-induced enhancement of regular oscillations of a system of magnetic dipoles

The dynamics of a system consisting of two bodies or a chain of bodies possessing dipole magnetic moments and moments of inertia is studied on the basis of numerical analysis. In constructing the parametric bifurcation diagram, the conditions for oscillatory modes with high noise sensitivity are determined. Features of this dynamics of coupled magnetic moments are considered, and spectral characteristics of these modes are calculated.

Viscoplastic flow in slightly varying channels with wall slip pertaining to a magnetorheological (MR) polishing process

In this paper, the first analytical endeavor into the fluid dynamic modeling of an MR polishing process is reported. The velocity and shear stress fields of an MR fluid running through a thin slippery channel with a slightly varying height are analytically solved using a bi-viscosity constitutive model and a Navier slip model. Estimations of the mechanical power density and the total power per unit depth applied onto the channel surfaces are also presented. Analytical solutions for the Couette–Poiseuille flow behavior of a bi-viscous fluid flowing through either parallel or non-uniform channels are obtained, and the associated necessary and sufficient conditions characterizing a total of 5 types of flow are derived. The behaviors of the fluid are examined through the use of a parametric diagram of Bingham number ( Bn) and Couette number ( Co), i.e., Bn– Co or 1/ Bn–1/ Co diagram, by changing the geometric and operating conditions. Using these diagrams, variations in the rheological characteristics of the flow are investigated in great detail, with a special focus on the movement of the pseudo-core region. Finally, the mechanical power density field obtained for the flow in a converging–diverging channel is used to explain the wear mechanism in the MR polishing process. The effects of the power density field and the total power on the material removal rate (MRR) and the within-workpiece nonuniformity (WIWNU) with respect to various geometric and operating conditions are evaluated.

D106 二輪自動車に対する前輪操舵アシスト制御のモデル駆動型システム開発(OS15 機械・制御系設計と1D-CAE 1)

This paper describes a system development of front-steering assist control for motorcycles using the model-based systems engineering approach. System analysis or verification and validation process on system level are clearly positioned in the systems engineering process as models of SysML (Systems Modeling Language). Test cases can be derived from use case analysis and the parametric diagram can be used to evaluate the performance of control system. In the trade-off study, measure of effectiveness should be shared among the multidisciplinary team associated to develop the system. The simulation results are validated in the test case defined in use case analysis, including a rider driving model.

Design of static and dynamic characteristics of a piezoelectric nanomicrotransducer

We design the static and dynamic characteristics of a piezoelectric nanomicrotransducer intended for use in nanotechnology and microelectronic hardware, devise its parametric structural schematic diagram, and determine the influence of its physical and geometric parameters on its static and dynamic characteristics.

JUMP RESONANCE IN DRIVEN CHUA'S CIRCUIT

In this brief letter new results regarding the discovery of jump resonance in driven Chua's circuit are given. Moreover, a parametric diagram characterizing this phenomenon is reported.

Investigation of static and dynamic characteristics of a piezomotor for nano-and micrometric movements

Static and dynamic characteristics of a piezomotor of nano-and micrometric movements for nanotechnology and microelectronics equipment are calculated, the parametric structural diagram of the piezomotor is constructed, and the influence of physical and geometric parameters of the piezomotor on the static and dynamic characteristics is determined.

Generalized structural-parametric model of electromagnetoelastic converter for control systems of nano- and micrometric movements: V. Multidimensional scheme

On the basis of solution of the wave equation and taking into account deformations over coordinate axes, the multidimensional structural-parametric model and the parametric structural diagram of the electromagnetoelastic converter in the form of a piezodrive of nanomotions are constructed. The influence of geometric and physical parameters of the piezodrive and the external load on its static and dynamical characteristics and transfer functions is determined. The parametric structural diagrams of multicoordinate piezo converters are obtained.

Optimisation of welding parameters in pulsed MIG/MAG welding with width-controlled sine-wave current pulses. Part 2: Determination of an optimum material transfer through the arc and a control method

The paper treats synergic pulsed MIG/MAG welding with width-controlled sine-wave current pulses. Such a pulse-current waveform will be obtained if a power source is controlled by thyristors integrated in a power circuit with a constant pulse frequency. A momentary pulse current power, which is a product of a momentary value of current and voltage, can be controlled by the delay time of thyristor ignition. The paper focuses on an analysis and optimisation of the material transfer through the arc using a limiting criterion determined by an isoparametric equation. By means of the results obtained in the investigation, a parametric diagram with the optimum welding region for a chosen droplet volume transferred through the arc can be determined. The material transfer established will satisfy the criteria set to ensure a stable droplet transfer with no spatter and production of a sound weld. It turned out that the type of synergic welding device suggested for pulsed MIG7/MAG welding was suitable for the most exacting applications.

Optimisation of welding parameters in pulsed MIG/MAG welding with width-controlled sine-wave current pulses. Part 1: Determination of a general synergic equation and a normalised parametric diagram with a defined parametric welding range

The paper treats synergic pulsed MIG/MAG welding with width-controlled sine-wave current pulses. Such a current-pulse waveform will be obtained if a power source is controlled by thyristors integrated in a power circuit. In this case the pulse frequency is constant and the current-pulse power can be controlled by the delay time of the thyristor ignition. The paper focuses on a theoretical derivation of a general synergic equation of pulsed MIG/MAG welding with width-controlled sine-wave current pulses that relates a mean welding current with pulsed welding parameters. On this basis, a normalised parametric diagram with a defined parametric welding range can be defined and elaborated, which permits a further analysis of pulsed welding and optimisation of pulsed welding parameters.

4.3.3 Applying Systems Modeling Language to A Simple Hardware System

AbstractThis paper used the Systems Modeling Language (SysML) to explore its applicability and effectiveness to a simple hardware system. The system and design requirements derived from the customer requirements were modeled in the requirements hierarchy diagram. The spring load equation with all the variables and constant were defined in the parametric constraint definition diagram. Parametric constraint on a block diagram was then used to design a conical helical spring. A link between design and requirements was demonstrated in the model. State machine diagrams depicted the finite state‐transition on how a person emptied the mousetrap and how a mouse entered the trap. These diagrams were linked to verification requirements for system verification. SysML is shown to be an effective modeling language for hardware systems. The applicability of SysML to a combined hardware and software system has still to be demonstrated and proven.

MODIFIED BIFURCATION DIAGRAMS IN AN APPROACH TO ONLINE PULSE SYSTEM DYNAMICS FORECASTING

Typically, online forecasting of pulse system dynamics assumes the usage of certain kinds of relevant a priori information. A bifurcation (or a parametric) diagram is one of the most informative forms of presentation of dynamics evolution. However, the data represented in this form is usually insufficient for one-to-one identification of the present system state and dynamics evolution direction, especially when online decision-making is necessary. In this paper two additional modified bifurcation diagrams are introduced. These diagrams provide a framework for deriving an algorithm which can be used to solve, in a step-by-step manner, a complex problem that consists in dynamics monitoring, identification and forecasting.

Numerical Analysis of Axisymmetric Buckling of a Conical Shell under Radial Compression

The nonlinear boundary-value problem of the axisymmetric buckling of a simply supported conical shell (dome) under a radial compressive load applied to the supported edge is formulated for a system of six first-order ordinary differential equations for independent fields of finite displacements and rotations. Multivalued solutions are obtained using the shooting method with specified accuracy. For various values of the loading parameter, bifurcation of the solutions of the problem is studied and a parametric branching diagram is constructed. The buckling modes are obtained for three branches of the solution. Curves of the buckling modes corresponding to three isolated branches of the solution are given.

Numerical Analysis of Axisymmetric Buckling of Plates under Radial Compression

Nonlinear boundary‐value problems of axisymmetric buckling of simply supported and clamped plates under radial compression are formulated for a system of six first‐order ordinary differential equations with independent fields of finite displacements and rotations. Multivalued solutions are obtained by the shooting method with specified accuracy. Bifurcation of the solutions of the problem is studied, and a parametric bifurcation diagram is constructed for various values of the loading parameter. Curves of buckling modes are given for three branches of the solution. The numerical results agree with available theoretical data.

Transitions from spatiotemporal chaos to cluster and complete synchronization states in a shift-invariant set of coupled nonlinear oscillators.

We study the spatiotemporal dynamics of a ring of diffusely coupled single-well Duffing oscillators. The transitions from spatiotemporal chaos to cluster and complete synchronization states are particularly investigated, as well as the Hopf bifurcations to instability. It is found that the underlying mechanism of these transitions relies on the motion of the representative points corresponding to the system's nondegenerated spatial transverse Fourier modes in the parametric Strutt diagram. A scaling law is used to demonstrate that the compact interval of the scalar coupling parameter values leading to cluster synchronization broadens in a square-power-like fashion as the number of oscillators is increased. The analytical approach is confirmed by numerical simulations.

A fuzzy multiple objective decision support model for energy-economy planning

In this paper an interactive approach to deal with fuzzy multiple objective linear programming problems is presented, which is based on the analysis of the decomposition of the parametric (weight) diagram into indifference regions corresponding to basic efficient solutions. This approach is illustrated to tackle uncertainty and imprecision associated with the coefficients of an input–output energy-economy planning model, aimed at providing decision support to decision makers in the study of the interactions between the energy system and the economy on a national level.

Liquid-liquid and liquid-solid phase separation and flocculation for a charged colloidal dispersion.

We model the intercolloidal interaction by a hard-sphere Yukawa repulsion to which is added the long-range van der Waals attraction. In comparison with the Derjaguin-Landau-Verwey-Overbeek repulsion, the Yukawa repulsion explicitly incorporates the spatial correlations between colloids and small ions. As a result, the repulsive part can be expressed analytically and has a coupling strength depending on the colloidal volume fraction. By use of this two-body potential of mean force and in conjunction with a second-order thermodynamic perturbation theory, we construct the colloidal Helmholtz free energy and use it to calculate the thermodynamic quantities, pressure and chemical potential, needed in the determination of the liquid-liquid and liquid-solid phase diagrams. We examine, in an aqueous charged colloidal dispersion, the effects of the Hamaker constant and particle size on the conformation of a stable liquid-liquid phase transition calculated with respect to the liquid-solid coexistence phases. We find that there exists a threshold Hamaker constant or particle size whose value demarcates the stable liquid-liquid coexistence phases from their metastable counterparts. Applying the same technique and using the energetic criterion, we extend our calculations to study the flocculation phenomenon in aqueous charged colloids. Here, we pay due attention to determining the loci of a stability curve stipulated for a given temperature T0, and obtain the parametric phase diagram of the Hamaker constant vs the coupling strength or, at given surface potential, the particle size. By imposing T0 to be the critical temperature T(c), i.e., setting k(B)T0 (=k(B)T(c)) equal to a reasonable potential barrier, we arrive at the stability curve that marks the irreversible/reversible phase transition. The interesting result is that there occurs a minimum size for the colloidal particles below (above) which the colloidal dispersion is driven to an irreversible (reversible) phase transition.