A Tool for Unbiased Comparison between Logarithmic and Floating-point Arithmetic

For applications requiring a large dynamic, real numbers may be represented either in floating-point, or in the logarithm number system (LNS). Which system is best for a given application is difficult to know in advance, because the cost and performance of LNS operators depend on the target accuracy in a highly non linear way. Therefore, a comparison of the pros and cons of both number systems in terms of cost, performance and overall accuracy is only relevant on a per-application basis. To make such a comparison possible, two concurrent libraries of parameterized arithmetic operators, targeting recent field-programmable gate arrays, are presented. They are unbiased in the sense that they strive to reflect the state-of-the-art for both number systems. These libraries are freely available at .

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Nanostructuring of Pure and Composite‐Based K6 Formulations with Low Sensitivities

The aim of this work was to desensitize keto‐RDX, respectively 2‐oxo‐1,3,5‐trinitro‐1,3,5‐triazacyclohexane (K6). For this purpose, two different methods were employed. First, nano‐K6 was produced by means of the Spray Flash Evaporation process. Particles with a median size of 74 nm were obtained. Sensitivity to friction and electrostatic discharge were reduced by downscaling particle size of K6. Second, due to their molecular analogy, the mixing of K6 and RDX was studied. For that reason, a physical nanometric mixture of K6 and RDX was produced by the same technique. In the latter case, an inter‐particular synergy between both compounds was noticed but without forming a cocrystal. The median particle size of the mixture is about 82 nm, and its sensitivity is between the ones of raw nano‐materials concerning friction and electrostatic discharge. Moreover, the mixture is less sensitive to impact (3.03 J) than nano‐K6 (<1.56 J) and nano‐RDX (threshold is 2.0 J).     

Parallel Computation for Radiative Heat Transfer Using the DOM in Combustion Applications: Direction,Frequency, Subdomain Decompositions,and Hybrid Methods

In the framework of coupled large-eddy/discrete ordinates method (LES/DOM) computations of turbulent combustion problems, various decompositions for parallel calculations of the radiative heat transfer based on the DOM are investigated. The methods analyzed are: (A) a task decomposition on the discrete directions and frequencies with two numeric strategies: Message Passing Interface (MPI) with distributed memory and OpenMP with shared memory for the direction decomposition; (B) a new algorithm for a DOM subdomain decomposition, which is proposed and tested using MPI; and (C) hybrid methods combining an OpenMP strategy for direction and MPI for tasks and subdomain decomposition. It is shown for the case of coupled simulations that the convergence and the parallel efficiency of the domain decomposition (B) are optimal. This method is limited in this work to 25 sub-domains, at which point the efficiency stagnates. Combining the directions with frequency and/or domain decompositions in a hybrid method (C) results in very good efficiency up to 1,200 processors. This hybrid strategy is also very efficient in terms of memory usage. This work shows that the best way to perform massively parallel computation for radiative heat transfer with the DOM is to combine different decomposition levels. The analysis performed in this work shows the best parallel strategy to be used in coupled simulations between radiation and LES on massively parallel architectures.     

Spatial disparities in accessibility to recreational amenities: the case of Pokémon GO

The Annals of Regional Science - In this study, we analyze spatial disparities in access to particular recreational amenities. We focus on the famous application for smart phones: Pokémon GO....     

基于有限元方法的塔机桁架结构屈曲分析

以塔式起重机的金属结构为主要研究对象,借助有限元平台,从简单杆件的分析入手获得了可行的线性屈曲与非线性屈曲分析的方法与流程,进而以此为基础从不同侧面对塔机桁架结构的屈曲问题进行了详细分析.研究结果表明：考虑载荷偏心和初始位移非线性屈曲分析的结果要比线性特征值屈曲分析的结果更符合实际状态.在塔机上计算时只考虑5％的载荷偏心就使结果比原来小了33％,而在实际情况中由于小车轨道不平、风载荷等原因引起的载荷偏心可能会更严重.     

Design support tools to sustain climate change adaptation at the local level: A review and reflection on their suitability

For mid-latitude cities, higher summer temperatures due to climate change are a cause for concern because they aggravate the urban heat island phenomenon and reduce thermal comfort inside buildings. By acquiring the appropriate knowledge and skills, architects and urban designers can become key actors in adaptation to climate change. Two workshops bringing together architects and urban designers provided evidence of deficiencies in this area. We hypothesize that a design support tool (DST) focused on the issue of adaptation of mid-latitude cities to rising summer temperatures could help improve knowledge and skills of professionals in the field. The first section presents the results taken from a review and classification of DSTs, which highlight the tools' features that are likely to reach this goal. Tools of the “hybrid” category seem most appropriate. To verify this, seven DSTs were selected and tested by fourteen students enrolled in a graduate-level architecture design studio. The second section presents the results from this test, including an analysis of the final projects, a web-based questionnaire and two focus groups. The relevance of hybrid approaches is established, but the results bring into question the capacity of a single DST to meet the individual and multiple needs of professionals.     

Types and Functions of Mitoribosome-Specific Ribosomal Proteins across Eukaryotes

Mitochondria are key organelles that combine features inherited from their bacterial endosymbiotic ancestor with traits that arose during eukaryote evolution. These energy producing organelles have retained a genome and fully functional gene expression machineries including specific ribosomes. Recent advances in cryo-electron microscopy have enabled the characterization of a fast-growing number of the low abundant membrane-bound mitochondrial ribosomes. Surprisingly, mitoribosomes were found to be extremely diverse both in terms of structure and composition. Still, all of them drastically increased their number of ribosomal proteins. Interestingly, among the more than 130 novel ribosomal proteins identified to date in mitochondria, most of them are composed of a-helices. Many of them belong to the nuclear encoded super family of helical repeat proteins. Here we review the diversity of functions and the mode of action held by the novel mitoribosome proteins and discuss why these proteins that share similar helical folds were independently recruited by mitoribosomes during evolution in independent eukaryote clades.     

PVS#: Streamlined Tacticals for PVS

The semantics of a proof language relies on the representation of the state of a proof after a logical rule has been applied. This information, which is usually meaningless from a logical point of view, is fundamental to describe the control mechanism of the proof search provided by the language. In this paper, we present a monadic datatype to represent the state information of a proof and we illustrate its use in the PVS theorem prover. We show how this representation can be used to design a new set of powerful tacticals for PVS, called PVS#, that have a simpler and clearer semantics compared to the semantics of standard PVS tacticals.     

Arterial hypertension: current large therapeutic trials

In this review, the design and objectives of ongoing clinical trials in essential hypertension are discussed along with the main results obtained from previously published therapeutic trials. In a meta-analysis of 14 of the major primary prevention trials in hypertension, the difference in diastolic blood pressure between the intervention groups and the control groups was only 5-6 mmHg. This difference was associated with significant reductions in all stroke events (42 per cent), all coronary heart disease events (14 per cent) and in cardiovascular mortality (21 per cent). In elderly hypertensive patients, available studies have shown that antihypertensive treatment reduces the incidence of non-fatal cardiovascular events without significantly modifying cardiovascular mortality. Most of these results were obtained with beta-blockers or diuretics. Despite official recommendation as first line monotherapy, none of the three new antihypertensive classes has been shown to have beneficial effects on hard primary endpoints such as cardiovascular morbidity and mortality. Several ongoing large scale randomized controlled trials vs. beta-blockers or diuretics are addressing this important issue. Moreover, other effects of antihypertensive treatment such as the 'J-curve phenomenon', the rate of change in the carotid wall thickness or the exact beneficial effects in elderly patients are being investigated in some of these studies.