Volume rendering is a very active research field in Computer Graphics because of its wide range of applications in various sciences, from medicine to flow mechanics. In this report, we survey a state-of-the-art on time-varying volume rendering. We state several basic concepts and then we establish several criteria to classify the studied works: IVR versus DVR, 4D versus 3D+time, compression tec...

Service systems abound with queues, but the most natural direct models are often timevarying queues, which require nonstandard analysis methods beyond stochastic textbooks. This paper surveys the literature on time-varying queues. Most of the literature concerns manyserver queues, which arise in large-scale service systems, such as in customer contact centers and hospital emergency departments,...

This work extends computational learning theory to situations in which concepts vary over time, e.g., system identification of a time-varying plant. We have extended formal definitions of concepts and learning to provide a framework in which an algorithm can track a concept as it evolves over time. Given this framework and focusing on memory-based algorithms, we have derived some PAC-style samp...

Time-varying gravitomagnetic fields are considered within the linear postNewtonian approach to general relativity. A simple model is developed in which the gravitomagnetic field of a localized mass-energy current varies linearly with time. The implications of this temporal variation of the source for the precession of test gyroscopes and the motion of null rays are briefly discussed. PACS numbe...

The development of the hardware systems has incurred various types of delays such as processing and transmission delays. Such delay may be due to the effect of tolerances of electronic components which were used while developing the system. Such time delay parameters must be implemented in the transfer function of the system so as to identify the correct cause of dynamic behavior of the system ...

in this paper, in order to optimize the portfolio consisting of selected industrial stocks of petroleum products, automobiles and parts, electrical industry and extraction of minerals from tehran stock exchange member, first, time – varying conditional covariance matrix has been estimated based on the following multivariate garch models: diagonal-vech (1,1), ccc (1,1) and diagonal -bekk (1,1). ...

Time-varying risk premia (TVRP) is one of the four sources of stock return autocorrelation. TVRP arises in a securities market equilibriumwhen the equilibrium expected returns of the available investments vary over time; in particular, the presence of TVRP does not indicate pricing inefficiency. This paper provides equilibrium upper bounds on TVRP, as a function of the return period, the time h...

N models typically suggest that prices rise in periods of high demand and cost. However, in many markets, prices fall when demand or costs rise. This inconsistency occurs because the normative models assume that competitive intensity does not change with demand and cost conditions over time. We therefore introduce the notion of time-varying competition by suggesting that it is important not onl...

Many kinds of objects and events in our world have a strongly time-dependent quality. However, most theories about concepts and categories either are insensitive to variation over time or treat it as a nuisance factor that produces irrational order effects during learning. In this article, we present two category learning experiments in which we explored peoples' ability to learn categories who...

Stochastic networks are a plausible representation of the relational information among entities in dynamic systems such as living cells or social communities. While there is a rich literature in estimating a static or temporally invariant network from observation data, little has been done toward estimating time-varying networks from time series of entity attributes. In this paper we present tw...