Book Review: The Strategic Constitution: Understanding Canadian Power in the World by Irvin Studin

This is a book review of The Strategic Constitution: Understanding Canadian Power in the World by Irvin Studi

The archaeological database—New relations?

Over two decades have passed since the foundations of the relational data model were formalised (Codd 1970) and today a large number of Database Management Systems (DBMS) based on its principles are readily available. The better of these have attained a high degree of sophistication, running in a variety of environments — micros, workstations, minis and mainframes — and have achieved some standardisation through the adoption of Standard (or Structured) Query Language (SQL). As such, the user who invests much time in learning to use a DBMS and its development tools, for example INGRES, will have little problem when the present micro is dumped and a workstation appears on the desk. More importantly for archaeological information, the data, its structure, and application programs will also transfer with minimal upheaval. This is a salutary warning to those investing a great deal of resources in non-upwardly mobile micro-based DBMS and they are urged to consider employing either ORACLE or INGRES (the current flagships of the 4th generation language multi- environment relational DBMS) if they wish to ensure the longevity of their work. The reference to work rather than just to data is deliberate and the cornerstone of this paper, for information is not just data values; it is the context and meaning of those values that ultimately determine the usefulness of the data. Data structure, user interfaces, validation procedures, help systems and applications are inextricably linked with the raw data, giving it context and providing a crude but non-trivial 'knowledge base' without which data files may be useless, or even a negative resource, if misunderstood. Although high-quality relational DBMS did not come into general use as commercial products until the late 1980s, deficiencies in the relational model had already been noted in the previous decade. Important new products are likely to become generally available soon. Many of the major research areas of general DBMS have direct application in the management of archaeological data. The aim of this paper is to discuss some of the limitations and deficiencies of currently available relational DBMS, to review informally the most relevant areas of development (and one area which has yet to be developed), and to consider the implications for mainstream archaeology

Smart receiver for visible light communications: Design and Analysis

This paper presents the concept, design and analysis for a visible light communications receiver to guard against blocking and enhance mobility. Different geometrical shapes have been investigated, with two being chosen and analyzed in MATLAB for the received power and the root–mean–square(RMS) delay spread. The results show that the receiver is fully mobile within the test area and can handle data rates far greater than that offered by commercially available LEDs

Depth perception not found in human observers for static or dynamic anti-correlated random dot stereograms

One of the greatest challenges in visual neuroscience is that of linking neural activity with perceptual experience. In the case of binocular depth perception, important insights have been achieved through comparing neural responses and the perception of depth, for carefully selected stimuli. One of the most important types of stimulus that has been used here is the anti-correlated random dot stereogram (ACRDS). In these stimuli, the contrast polarity of one half of a stereoscopic image is reversed. While neurons in cortical area V1 respond reliably to the binocular disparities in ACRDS, they do not create a sensation of depth. This discrepancy has been used to argue that depth perception must rely on neural activity elsewhere in the brain. Currently, the psychophysical results on which this argument rests are not clear-cut. While it is generally assumed that ACRDS do not support the perception of depth, some studies have reported that some people, some of the time, perceive depth in some types of these stimuli. Given the importance of these results for understanding the neural correlates of stereopsis, we studied depth perception in ACRDS using a large number of observers, in order to provide an unambiguous conclusion about the extent to which these stimuli support the perception of depth. We presented observers with random dot stereograms in which correlated dots were presented in a surrounding annulus and correlated or anti-correlated dots were presented in a central circular region. While observers could reliably report the depth of the central region for correlated stimuli, we found no evidence for depth perception in static or dynamic anti-correlated stimuli. Confidence ratings for stereoscopic perception were uniformly low for anti-correlated stimuli, but showed normal variation with disparity for correlated stimuli. These results establish that the inability of observers to perceive depth in ACRDS is a robust phenomenon

Real-Time Experimental Demonstration of Multi-band CAP Modulation in a VLC System with Off-the-Shelf LEDs

We demonstrate, for the first time, m-CAP modulation using off-the-shelf LEDs in a VLC in real time experimental setup using field programmable gate arrays based in universal software radio peripherals (USRPs). We demonstrate transmission speeds up to ~30 Mb/s can be achieved, which supports high definition television streaming.Comment: 2 pages, 4 figures, IEEE INFOCOM Demonstration

Discussion of “Reclaimed Lignin-Stabilized Silty Soil: Undrained Shear Strength, Atterberg Limits, and Microstructure Characteristics” by T. Zhang, G. Cai and S. Li

The discussers read with interest the recent paper by Zhang et al. (2018), which reports on the investigation of the effects of 0–12% lignin additive on some index and shear strength properties of a silty soil material. The use of the fall-cone device to study undrained shear strength variation with moisture content is pleasing to see and shows how the approach is useful for this purpose: namely the study of undrained strength variation. We wish to make the following comments regarding some of the underlying assumptions in the paper by way of offering some other explanations and interpretations for the results obtained

Experimental SEFDM Pipelined Iterative Detection Architecture with Improved Throughput

In spectrally efficient frequency division multiplexing (SEFDM), the separation between subcarriers is reduced below the Nyquist criteria, enhancing bandwidth utilisation in comparison to orthogonal frequency division multiplexing (OFDM). This leads to self-induced inter-carrier interference (ICI) in the SEFDM signal, which requires more sophisticated detectors to retrieve the transmitted data. In previous work, iterative detectors (IDs) have been used to recover the SEFDM signal after processing a certain number of iterations, however, the sequential iterative process increases the processing time with the number of iterations, leading to throughput reduction. In this work, ID pipelining is designed and implemented in software defined radio (SDR) to reduce the overall system detection latency and improve the throughput. Thus, symbols are allocated into parallel IDs that have no waiting time as they are received. Our experimental findings show that throughput will improve linearly with the number of the paralleled ID elements, however, hardware complexity also increases linearly with the number of ID elements

Visible Light Communications: Simplified Co-Equalisation of Fast OFDM in a Multiple-Input Multiple-Output Configuration

In this paper we experimentally demonstrate, for the first time, a simplified co-equalisation for imaging multiple-input multiple-output based visible light communication systems. We show that in such systems, where all channels have similar magnitude responses, an equaliser trained on a single channel produces coefficients that may be used in the form of a look-up table to equalise the remaining channels without the need for explicit or bespoke training. The system demonstrated is based on the fast-orthogonal frequency division multiplexing based on pulse amplitude modulation scheme to improve the spectral efficiency, where a data rate of 80 Mb/s is achieved using four light-emitting diodes, each of a 4 MHz raw bandwidth. We show that the reported system performance closely matches that of the traditional and more computationally complex system in terms of bit-error rate