Experimenting with computing

AbstractWe distinguish two kinds of experimental activity: post-theory and exploratory. Post-theory experiment enjoys computer support that is well-aligned to the classical theory of computation. Exploratory experiment, in contrast, arguably demands a broader conception of computing. Empirical Modelling (EM) is proposed as a more appropriate conceptual framework in which to provide computational support for exploratory experiment. In the process, it promises to provide integrated computational support for both exploratory and post-theory experiment. We first sketch the motivation for EM and illustrate its potential for supporting experimentation, then briefly highlight the semantic challenge it poses and the philosophical implications

Some Notes on the Past and Future of Lisp-Stat

Lisp-Stat was originally developed as a framework for experimenting with dynamic graphics in statistics. To support this use, it evolved into a platform for more general statistical computing. The choice of the Lisp language as the basis of the system was in part coincidence and in part a very deliberate decision. This paper describes the background behind the choice of Lisp, as well as the advantages and disadvantages of this choice. The paper then discusses some lessons that can be drawn from experience with Lisp-Stat and with the R language to guide future development of Lisp-Stat, R, and similar systems.

Oceanographic and underwater acoustics research : conducted during the period 1 November 1960 - 30 April 1961

Digital computing techniques have been used in special computing applications in underwater acoustics at WHOI for many years, but recently we have commenced intensive application of digital data handling and computing facilities to a variety of computing, data storage, and data handling problems. Progress in these applications is described under Acoustic Instrumentation below. Some bathymetric studies carried out recently under another contract have shown that even very narrow-beam, single-beam echo sounders simply cannot provide reliable depth sounding information where the topography is complex. In this work we have been experimenting with the inverted echo sounder, discussed below, originally developed to measure depth of the sound velocimeter. The inverted echo sounder is lowered to a position within a few feet of the bottom. The total acoustic travel time from surface to bottom may be read as the sum of the travel times from the instrument to the bottom and surface . True depth is then computed in the usual way with appropriate s cnmd velocity data. In its present form the inverted echo sounder is suitable for mapping ~mall areas~ a few square miles, provided there is a suitable means of positioning the instrument. We have experimented with radio-acoustic navigation, and intend to experiment with vertical triangulation from the suspending ship as well. Steady demands for new, modified, and improved instrumentation have been responded to in echo sounding, seismic profiling, and spectrum analysis, as detailed below.Undersea Warfare Branch Office of Naval Research Under Contracts Nonr-1367(00)NR261-102 and Nonr-2129(00)NR261-10

Cloud Security Issues

The emergence of cloud computing is a recent development, insights into critical aspects of security can be gleaned from reported experiences of early adopters and also from researchers analyzing and experimenting with available cloud provider platforms and associated technologies. The sections below highlight privacy and security-related issues that are believed to have long-term significance for public cloud computing and, in many cases, for other cloud computing service models. Because cloud computing has grown out of an amalgamation of technologies, including service oriented architecture, virtualization, Web 2.0, and utility computing, many of the privacy and security issues involved can be viewed as known problems cast in a new setting. The importance of their combined effect in this setting, however, should not be discounted. Public cloud computing does represent a thought-provoking paradigm shift from conventional norms to an open deperimeterized organizational infrastructure—at the extreme, displacing applications from one organization’s infrastructure to the infrastructure of another organization, where the applications of potential adversaries may also operate. Keywords: cloud security, IaaS, Privac

A Simulation of Demand-Driven Dataflow: Translation from Lucid into MDC Language

Message Driven Computation (MDC) is a model of computation with which they have been experimenting at the Illinois Institute of Technology. The authors aim to prove the viability of MDC in practice for the expression of parallel algorithms and the implementation of functional and dataflow programming languages. In the paper they discuss their implementation of the Lucid programming language in MDC. The discussion presents a subset of Lucid which illustrates the principles of Lucid, Message Driven Computing, and the translation into and the interpretation of dataflow graphs