Nowadays, there is an increasing use of sampling methods in network and spatial populations. Although the most common link-tracing designs such as adaptive cluster sampling and snowball sampling have advantages over conventional sampling designs such as simple random sampling and cluster sampling, these designs still present many drawbacks. Adaptive web sampling is a new link-tracing design tha...

In the present paper, the Zelt algorithm has been extended for ray tracing through an anisotropic model. In anisotropic media, the direction of the propagated energy generally differs from that of the plane-wave propagation. This makes velocity values to be varied in different directions. Therefore, velocity modeling in such media is completely different from that in an isotropic media. The vel...

Software customers want both sufficient product quality and agile response to requirements changes. Formal software requirements tracing helps to systematically determine the impact of changes and to keep track of development artifacts that need to be re-tested when requirements change. However, full tracing of all requirements on the most detailed level can be very expensive and time consuming...

Streamline methods for subsurface-flow simulation have received renewed attention as fast alternatives to traditional finite volume or finite element methods. Key aspects of streamline simulation are the accurate tracing of streamlines and the computation of travel time along individual streamlines. In this paper, we propose a new streamline tracing framework that enables the extension of strea...

One of the more bothersome aspects of developing a parallel program is that of monitoring the behavior of the program for debugging and performance tuning. Often there is no intrinsic support for examining program state and dynamics in a parallel programming system, let alone a useful interface for analyzing or visualizing that information. This paper discusses an enhanced tracing facility and ...

In networks, nodes may preferentially contact other nodes with similar (assortatively mixed) or dissimilar (disassortatively mixed) numbers of contacts. Different patterns of contact support different epidemic dynamics, potentially affecting the efficacy of control measures such as contact tracing, which aims to identify and isolate nodes with infectious contacts. We used stochastic simulations...

Traditional tracing mechanisms were usually developed for use in a single-computer environment. Moreover, they are bound to a speci c programming language. Today's highly distributed and heterogeneous computing environments require new tracing methodologies. The paper addresses this problem by reviewing ways how the middleware might and should support tracing. In particular, CORBA meta-objects ...

This paper describes a parallel processing scheme for bidirectional ray tracing which improves the reality of the image drastically. It is organized from two stages, i.e. light ray tracing and viewing ray tracing. In light ray tracing, pairs of a light source and an element of objects are distributed to each processor dynamically. In viewing ray tracing, we use a screen subdivision al­ gorithm....