Principles of Neuromorphic Photonics

In an age overrun with information, the ability to process reams of data has become crucial. The demand for data will continue to grow as smart gadgets multiply and become increasingly integrated into our daily lives. Next-generation industries in artificial intelligence services and high-performance computing are so far supported by microelectronic platforms. These data-intensive enterprises rely on continual improvements in hardware. Their prospects are running up against a stark reality: conventional one-size-fits-all solutions offered by digital electronics can no longer satisfy this need, as Moore's law (exponential hardware scaling), interconnection density, and the von Neumann architecture reach their limits. With its superior speed and reconfigurability, analog photonics can provide some relief to these problems; however, complex applications of analog photonics have remained largely unexplored due to the absence of a robust photonic integration industry. Recently, the landscape for commercially-manufacturable photonic chips has been changing rapidly and now promises to achieve economies of scale previously enjoyed solely by microelectronics. The scientific community has set out to build bridges between the domains of photonic device physics and neural networks, giving rise to the field of \emph{neuromorphic photonics}. This article reviews the recent progress in integrated neuromorphic photonics. We provide an overview of neuromorphic computing, discuss the associated technology (microelectronic and photonic) platforms and compare their metric performance. We discuss photonic neural network approaches and challenges for integrated neuromorphic photonic processors while providing an in-depth description of photonic neurons and a candidate interconnection architecture. We conclude with a future outlook of neuro-inspired photonic processing.Comment: 28 pages, 19 figure

A survey of current trends in incorporating virtual reality and geographical information systems

The paper describes the results of a comprehensive literature and Internet survey on current trends in virtual Reality GIS (VRGIS). In the first part of the paper, a background of VRGIS is set, followed by the description and classification of the main research areas which focus in VRGIS research with an attempt to clarify the reasons that led the researchers to pursue a VR solution for the specific problems in their research field. Based on the observations from the current practice, the main definitions of VRGIS are discussed in the third section. Finally, future directions and possibilities for development are drawn

A Survey of Current Trends in Incorporating Virtual Reality and GIS

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GHOST: Building blocks for high performance sparse linear algebra on heterogeneous systems

While many of the architectural details of future exascale-class high performance computer systems are still a matter of intense research, there appears to be a general consensus that they will be strongly heterogeneous, featuring "standard" as well as "accelerated" resources. Today, such resources are available as multicore processors, graphics processing units (GPUs), and other accelerators such as the Intel Xeon Phi. Any software infrastructure that claims usefulness for such environments must be able to meet their inherent challenges: massive multi-level parallelism, topology, asynchronicity, and abstraction. The "General, Hybrid, and Optimized Sparse Toolkit" (GHOST) is a collection of building blocks that targets algorithms dealing with sparse matrix representations on current and future large-scale systems. It implements the "MPI+X" paradigm, has a pure C interface, and provides hybrid-parallel numerical kernels, intelligent resource management, and truly heterogeneous parallelism for multicore CPUs, Nvidia GPUs, and the Intel Xeon Phi. We describe the details of its design with respect to the challenges posed by modern heterogeneous supercomputers and recent algorithmic developments. Implementation details which are indispensable for achieving high efficiency are pointed out and their necessity is justified by performance measurements or predictions based on performance models. The library code and several applications are available as open source. We also provide instructions on how to make use of GHOST in existing software packages, together with a case study which demonstrates the applicability and performance of GHOST as a component within a larger software stack.Comment: 32 pages, 11 figure

Evidence-Based Design: Theoretical and Practical Reflections of an Emerging Approach in Office Architecture

Evidence-based design is a practice that has emerged only relatively recently, inspired by a growing popularity of evidence-based approaches in other professions such as medicine. It has received greatest attention in design for the health sector, but has received less in office architecture, although this would seem not only to be beneficial for clients, but increasingly important in a changing business environment. This paper outlines the history and origins of evidence-based practice, its influence in the health sector, as well as some of the reasons why it has been found more difficult to apply in office architecture. Based on these theoretical reflections, data and experiences from several research case studies in diverse workplace environments are presented following a three part argument: firstly we show how organisational behaviours may change as a result of an organisation moving into a new building; secondly we argue that not all effects of space on organisations are consistent. Examples of both consistent and inconsistent results are presented, giving possible reasons for differences in outcomes. Thirdly, practical implications of evidence-based design are made and difficulties for evidence-based practice, for example the problem of investment of time, are reflected on. The paper concludes that organisations may be distinguished according to both their spatial and transpatial structure (referring to a concept initially introduced by Hillier and Hanson in their study of societies). This means that evidence-based design in office architecture needs to recognise that it deals with a multiplicity of possible organisational forms, with specific clients requiring case-dependent research and evidence gathering. In this evidence-based design practice differs markedly from evidence-based medicine. Finally, we suggest a framework for systematic review inclusion criteria in the development of Evidence-Based Design as a field of practice. We argue that it is only through the development of an approach tailored to the specific nature of design practice and organisational function that research evidence can properly be brought to bear. Keywords: Architecture; Design Practice; Evidence-Based Design; Workplace; Research; Case Study.</p

Hierarchical Parallelisation of Functional Renormalisation Group Calculations -- hp-fRG

The functional renormalisation group (fRG) has evolved into a versatile tool in condensed matter theory for studying important aspects of correlated electron systems. Practical applications of the method often involve a high numerical effort, motivating the question in how far High Performance Computing (HPC) can leverage the approach. In this work we report on a multi-level parallelisation of the underlying computational machinery and show that this can speed up the code by several orders of magnitude. This in turn can extend the applicability of the method to otherwise inaccessible cases. We exploit three levels of parallelisation: Distributed computing by means of Message Passing (MPI), shared-memory computing using OpenMP, and vectorisation by means of SIMD units (single-instruction-multiple-data). Results are provided for two distinct High Performance Computing (HPC) platforms, namely the IBM-based BlueGene/Q system JUQUEEN and an Intel Sandy-Bridge-based development cluster. We discuss how certain issues and obstacles were overcome in the course of adapting the code. Most importantly, we conclude that this vast improvement can actually be accomplished by introducing only moderate changes to the code, such that this strategy may serve as a guideline for other researcher to likewise improve the efficiency of their codes

Geoweb 2.0 for Participatory Urban Design: Affordances and Critical Success Factors

In this paper, we discuss the affordances of open-source Geoweb 2.0 platforms to support the participatory design of urban projects in real-world practices.We first introduce the two open-source platforms used in our study for testing purposes. Then, based on evidence from five different field studies we identify five affordances of these platforms: conversations on alternative urban projects, citizen consultation, design empowerment, design studio learning and design research. We elaborate on these in detail and identify a key set of success factors for the facilitation of better practices in the future