PPUAS--photopeak unfolding and self-shielding program

Computer code was developed to determine radioactive emission rates of nuclear fuels. Code is basically written for two different source geometries; however, unfolding routine can be executed for other source geometries

The influences of environmental conditions on source localisation using a single vertical array and their exploitation through ground effect inversion

The performance of microphone arrays outdoors is influenced by the environmental conditions. Numerical simulations indicate that, while horizontal arrays are hardly affected, direction-of-arrival (DOA) estimation with vertical arrays becomes biased in presence of ground reflections and sound speed gradients. Turbulence leads to a huge variability in the estimates by reducing the ground effect. Ground effect can be exploited by combining classical source localization with an appropriate propagation model (ground effect inversion). Not only does this allow the source elevation and range to be determined with a single vertical array but also it allows separation of sources which can no longer be distinguished by far field localization methods. Furthermore, simulations provide detail of the achievable spatial resolution depending on frequency range, array size and localization algorithm and show a clear advantage of broadband processing. Outdoor measurements with one or two sources confirm the results of the numerical simulations

Communication Over MIMO Broadcast Channels Using Lattice-Basis Reduction

A simple scheme for communication over MIMO broadcast channels is introduced which adopts the lattice reduction technique to improve the naive channel inversion method. Lattice basis reduction helps us to reduce the average transmitted energy by modifying the region which includes the constellation points. Simulation results show that the proposed scheme performs well, and as compared to the more complex methods (such as the perturbation method) has a negligible loss. Moreover, the proposed method is extended to the case of different rates for different users. The asymptotic behavior of the symbol error rate of the proposed method and the perturbation technique, and also the outage probability for the case of fixed-rate users is analyzed. It is shown that the proposed method, based on LLL lattice reduction, achieves the optimum asymptotic slope of symbol-error-rate (called the precoding diversity). Also, the outage probability for the case of fixed sum-rate is analyzed.Comment: Submitted to IEEE Trans. on Info. Theory (Jan. 15, 2006), Revised (Jun. 12, 2007

Virtual Pitch and Pitch Shifts in Church Bells

It is well established that musical sounds comprising multiple partials with frequencies approximately in the ratio of small integers give rise to a strong sensation of pitch even if the lowest or fundamental partial is missing—the so-called virtual pitch effect. Experiments on thirty test subjects demonstrate that this virtual pitch is shifted significantly by changes in the spacing of the constituent partials. The experiments measured pitch by comparison of sounds of similar timbre and were automated so that they could be performed remotely across the Internet. Analysis of the test sounds used shows that the pitch shifts are not predicted by Terhardt’s classic model of virtual pitch. The test sounds used were modelled on the sounds of church bells, but a further experiment on seventeen test subjects showed that changes in partial amplitude only had a minor effect on the pitch shifts observed, and that a pitch shift was still observed when two of the lowest frequency partials were removed, so that the effects reported are of general interest

Acoustic propagation over periodic and quasi-periodic rough surfaces

Transport noise is an ever present concern in urban areas affecting the quality of life for millions of people. The traditional noise barrier is not always a convenient method of noise control and can divide communities. Deliberate introduction of small scale (0.3 m high or less) periodic roughness on otherwise acoustically-hard ground has been investigated as a way of reducing noise near to a surface transport corridor. The roughness alters the effective surface impedance of the ground and thereby creates a 'soft' ground effect. Moreover the effectiveness if the rough surface is not reduced significantly if there are pathways through it. However the rough ground also creates surface waves that must be absorbed for the noise reduction to be effective. An alternative way of reducing surface waves may be to alter the periodicity. The effects of altering the periodicity of circular rods placed on a hard surface in the laboratory have been investigated. Predictions of multiple scattering theory and a boundary element code have been compared with the experimental data

SCMA Codebook Design

Multicarrier CDMA is a multiple access scheme in which modulated QAM symbols are spread over OFDMA tones by using a generally complex spreading sequence. Effectively, a QAM symbol is repeated over multiple tones. Low density signature (LDS) is a version of CDMA with low density spreading sequences allowing us to take advantage of a near optimal message passing algorithm (MPA) receiver with practically feasible complexity. Sparse code multiple access (SCMA) is a multi-dimensional codebook-based non-orthogonal spreading technique. In SCMA, the procedure of bit to QAM symbol mapping and spreading are combined together and incoming bits are directly mapped to multi-dimensional codewords of SCMA codebook sets. Each layer has its dedicated codebook. Shaping gain of a multi-dimensional constellation is one of the main sources of the performance improvement in comparison to the simple repetition of QAM symbols in LDS. Meanwhile, like LDS, SCMA enjoys the low complexity reception techniques due to the sparsity of SCMA codewords. In this paper a systematic approach is proposed to design SCMA codebooks mainly based on the design principles of lattice constellations. Simulation results are presented to show the performance gain of SCMA compared to LDS and OFDMA.Comment: Accepted for IEEE VTC-fall 201

Effects of a One-Day Krav Maga Training: Early Stages of Skill Acquisition of a Krav Maga Kick and Punch

Krav Maga (KM), inspired by various forms of martial arts, is a form of self-defence training intended to teach civilians the necessary techniques required to fight against street violence. KM offers self-defence training in over 70 countries to a variety of populations. Moreover, in countries such as U.S.A and France, KM is an integral part of the military and police training. Although many forms of martial arts have been studied for decades, theres few mentions of KM in the current literature. The current study investigated the effectiveness of a 30-minute instructional session among seventeen female volunteers. The participants displayed a 42% increase in kick peak force when compared to their baseline. This change in performance is most likely associated with KM instruction and is perhaps demonstrating characteristics of learning among novice

Tracing Pathways of Resource Use in the World Economy: An Analysis of National and Sectoral Influence across the Global Water-Energy-Land System

A research and policy agenda has emerged in recent years to understand the interconnected risks natural resource systems face and their exploitation drives. The so-called Water-Energy-Food (WEF) nexus has served as a focal point for the conceptual, theoretical and empirical development of this agenda. However, boundaries for WEF nexus assessment are usually established without a foundational understanding of major interactions and risks across the water-energy-land (WEL) system. Consequently, priorities drawn from nexus studies might simply be an artefact of the partial scope of nexus assessment rather than a reflection of major risks to the WEL system and the activities which it supports. This thesis demonstrates how macro-economic methods of resource accounting can be used to broaden nexus assessment, sectorally and spatially, to identify and compare different sources of water, energy and land use, in individual countries and globally. A study of water and land use embodied in international soybean trade (Chapter 3) reveals that while single commodities can be analysed in this way, data and time constraints involved in using Material Flow Analysis (MFA) data make global assessment of water, energy and land use pathways across different production and consumption systems challenging. However, Multi-Regional Input-Output Analysis (MRIOA) is found to offer a practical approach to this end. By combining economic and environmental accounts from the Eora MRIO database, resource risk indices, and techniques for production source decomposition, this thesis examines thewater, energy and land footprints of 189 countries. Chapter 4 evaluates the scale of national water, energy and land use embodied in domestic production and international trade; Chapter 5 compares the contribution of food and non-food related sectors within this context; and, Chapter 6 reveals how these impacts are distributed across supply networks. Linking national consumption to resource origins reveals that countries are often highly exposed to over-exploited, insecure, and degraded water, energy, and land resources. These risks are found to originate from multiple sectors, including food, textiles and construction, and are primarily indirect, stemming from international trade and production up-stream national supply networks. These findings highlight the partiality of studying the WEL system within a single sector, across a limited supply chain scope, and at a sub-global scale. Policy interventions within this context need to reflect how resource pressures are transmitted through consumption and production systems between local, national, and global scales. However, further research is also needed to expose the links between inequality, ideology, overconsumption and environmental exploitation which drive decisions in relation to water, energy and land resources.Cambridge Commonwealth Trust: Vice Chancellor's Awar

Learning pathways into sustainable agriculture: the motivations and approaches of young entrant farmers

The research project Learning Pathways into Sustainable Agriculture was undertaken in the summer of 2019 in order to shed light on the experiences of a growing number of young people who choose to enter sustainable agriculture from non farming backgrounds. Transforming the UK food system requires us to look ahead and ensure that we nourish the small shoots today which will form important parts of our sustainable food system tomorrow. This means not only tackling the challenge of retaining people in farming and supporting their transition to sustainable agriculture but also, and importantly, attracting and supporting new entrants into agriculture. The report highlights both the incredible enthusiasm and energy young new entrants are bringing to the farming sector and the many challenges they face in a system which offers little support for them. To encourage the creation of more sustainable farm businesses in the UK, a crucial starting point is supporting new farmers’ learning pathways into sustainable agriculture