Kinds Of Time Scales Research Articles

Systematic Design Applied in Outdoor Spatiotemporal Lighting

Outdoor lighting design consists of many different objectives, depending on the area that is illuminated. In addition, besides functional lighting, extra messages may be superimposed to a lighting configuration. This adds to the complexity of the lighting design. Furthermore, temporal variations in lighting may be used as an additional tool of expressivity. All the above require some basic training and also some familiarity with expression tools. In this work, a framework is given for seamless communication through lighting, including both spatial and temporal lighting patterns. To this end, two different kinds of time scales are considered, leading to case studies for both seasonal lighting and communication through rapid spatiotemporal differentiations in it. The framework is two-fold, allowing for both diagrammatic and quasi-algebraic elaboration, leading to interesting visual results and providing the first step towards optimization. Different cases of outdoor lighting are considered as case studies, namely façade lighting and glass cases. These are used to illustrate the applicability and the added value of the current framework, that is, the systematization of the lighting procedure taking into account artistic interventions, which can be considered an extension of utilizing semantics.

Matter of Time: Ceramics and Historicity in Medieval South India

This article examines how people formed and negotiated relations to time in routine engagements with materials and places in medieval South India. Questions of history and memory, which have become central to our understanding of precolonial Indian social and political practices, are frequently considered in relation to courtly epigraphical and textual production or monumental building projects. Positing that experiences of time are formed in everyday acts of production, consumption and maintenance, this article problematises the term ‘social memory’ to propose an alternative framework for exploring temporal relations: the concept of historicity. Historicity provides a robust analytical vocabulary for discussing how historical actors inhabited their own present, how they oriented themselves towards pasts and futures, and the kinds of timescales that both framed their actions and were formed in action. Operationalising this framework, I build on an analysis of excavated ceramics from a twelfth- to thirteenth-century settlement at Maski (northern Karnataka) to foreground the diverse ways in which individuals and communities drew upon available pasts and acted with initiative within an intersubjective present world of tasks and activities.

Qualitative Theory of Differential, Difference, and Dynamic Equations

Differential, difference, and dynamic equations are used for modeling many problems arising in the engineering and natural sciences. Therefore, analysis of qualitative properties of solutions to such equations is crucial for applications. It is important to develop new theories and methods, as well as to modify and refine thewell-known techniques, for the analysis of new classes of problems. We received 11 papers for possible publication. Five papers published in this special issue address a number of challenging problems. The special issue opens with the contribution by Professor R. P. Silva who gives the characterization of the limiting behavior of solutions of elliptic equations driven by the p-Laplacian operator with Neumann boundary conditions posed in a family of thin domains. Professors Z. Luo et al. consider a class of generalized nspecies Lotka-Volterra type and Gilpin-Ayala type competition systems with multiple delays and impulses. Using Krasnoselskii fixed point theorem in a cone of Banach space, they derive some verifiable necessary and sufficient conditions for the existence of positive periodic solutions of the previously mentioned. As applications, some special cases of the previous system are examined and some earlier results are extended and improved. Professors M. Unal and Y. N. Raffoul use the fixed point theory to investigate the qualitative analysis of a nonlinear delay dynamic equation on an arbitrary time scale.They illustrate new results by applying them to various kinds of time scales. In the paper by Professor A. Reinfelds, the conjugacy of a discrete semidynamical system and its partially decoupled discrete semidynamical system in a Banach space is proved in a neighbourhood of the nontrivial invariant manifold. The contribution by Professors S. H. Da Silva et al. closes this special issue. They show normal hyperbolicity property of curves of equilibria andprove the continuity of global attractors for the flow of a class of nonlocal evolution equations with respect to some functional parameter. We hope that this collection of papers will attract interest of researchers working in related areas and will stimulate further progress in the Qualitative Theory of Differential, Difference, and Dynamic Equations.

Dynamic Simulation of a Solid Oxide Fuel Cell System for Micro Combined Heat and Power Application

In the past decade, developing solid oxide fuel cell (SOFC) systems for micro combined heat and power applications (micro-CHP, 1-10 kWe) is one of the hot spots in the world energy field. To meet the requirements for system optimization and control design of SOFC micro-CHP systems, in this paper a dynamic model of an SOFC micro-CHP system is developed, based on which dynamic simulations are also carried out. Simulation results show that the present model can reflect the behavior of the SOFC micro-CHP system quite well; the influence of one component on another is an important factor to determine system dynamic behavior; as the system comprises many components and concerns different physical and chemical processes, it has dynamic processes with several kinds of time scales; for the air preheating need, the heat-exchange area of air pre-heater is quite big, which leads to its big thermal inertia, and causes the dynamic process lasting for several ten thousands of seconds.

Two-Dimensional Software Defect Models with Test Execution History

In general, the software-testing time may be measured by two kinds of time scales: calendar time and test execution time. In this paper, we develop two-dimensional software reliability models with two-time measures and incorporate both of them to assess the software reliability with higher accuracy. Since the resulting software defect models are based on the familiar nonhomogeneous Poisson processes with two time scales, which are the natural extensions of one-dimensional software defect models, it is possible to treat the time data both simultaneously and effectively. We investigate the dependence of test-execution time as a testing effort on the software reliability assessment and validate quantitatively the software defect models with two-time scales. We also consider an optimization problem when to stop the software testing in terms of two-time measurements.

On the asymptotics of solutions of delay dynamic equations on time scales

We study the asymptotic properties of first order delay dynamic equations on time scales. Our aim is to generalize and extend some asymptotic formulae derived for delay differential and difference equations. We illustrate our results by applying them to various kinds of time scales.

Numerical Analysis of Pressure Propagation and Energy Conversion Ratio in Sodium Vapor Explosions

A computer code PROVER-II is developed for the propagation phase of a sodium vapor explosion. A new thermal fragmentation model is proposed that includes three kinds of timescales for modeling the instant fragmentation, spontaneous nucleation fragmentation, and normal boiling fragmentation. The pressure wave propagation in a sodium vapor explosion is analyzed and compared with that in a steam explosion. The energy conversion ratio of an in-vessel sodium vapor explosion is calculated by using hydrodynamic and thermal fragmentation mechanisms, and sensitivity analyses are carried out for some parameters. The initial thermal conditions for energetic fuel-coolant interactions in a sodium system are examined. Results show that the high saturation temperature of sodium results in a much lower pressure peak in a sodium vapor explosion compared to a steam explosion, and the mechanical energy release is limited by the mass of melt participating in the explosion during the core disruptive accident in liquid-metal-cooled fast breeder reactors.

Dynamic scaling theory for a tethered membrane in solution.

We present the dynamic scaling behavior for the specific viscosity and diffusion coefficient of a single membrane and membranes with nonzero concentration in solution. Starting from the membrane free energies, we derive their Langevin equations. The corresponding Kirkwood diffusion equation, describing the time evolution in configuration space, contains two kinds of time scales that are separated by the external dimension 4/(2-D) where D is the dimension of the internal space. These time scale separation behaviors depend strongly on the hydrodynamic screening effect. For a single membrane solution, we resolve the dynamic scaling exponents for the diffusion coefficient and intrinsic viscosity by the dimension reduction method. For a concentrated membrane solution, the effective excluded volume strength and draining parameter are introduced. The effective medium argument is applied to obtain a concentration dependent power law form for the specific viscosity and diffusion coefficient, whose results contribute to a fundamental understanding of membrane in solution and of hydrodynamic screening and excluded volume effects in many different solvents.

The anharmonic features of the short-time dynamics of fluids: The time evolution and mixing of instantaneous normal modes

Despite the obvious role of sharply varying repulsive forces in determining the structure of most liquids, for short periods of time, motion in liquids looks remarkably harmonic. That is, there seem to be well-defined collective, but independent, harmonic modes governing the ultrafast dynamics launched from any given liquid configuration. Because liquids are not truly harmonic, however, these modes cannot last forever. In particular, “instantaneous” modes of this sort eventually have to give way to new instantaneous modes—ones more appropriate to whatever new configuration the liquid has evolved into. In this paper we investigate just this process of mode evolution. By concentrating on solely the highest frequency modes, it is possible to formulate analytical models for both the modes and the anharmonic interactions that affect them. We can therefore begin to understand the mechanisms by which modes change in time and the kinds of time scales on which the specific anharmonic processes occur in liquids. What we find is that there are several rather distinct signatures of anharmonicity: we see first that the anharmonicity within a mode itself continually causes the mode frequency to fluctuate. More sporadically, we find that two different but nearly resonant modes will sometimes interact strongly enough with one another to cause a temporary—though not a permanent—mixing between the modes. Of course, both of these processes are, in some sense, breakdowns of instantaneous-normal-mode theory, but neither of them affects the basic identity and existence of instantaneous modes. The eventual destruction of the modes turns out to be an even less frequent event precipitated by an even stronger mixing between a mode and the motion of surrounding atoms. It is precisely this longer time scale that may mark the first point at which diffusive motion plays an essential role in liquid dynamics.