NACU: A Non-Linear Arithmetic Unit for Neural Networks

Reconfigurable architectures targeting neural networks are an attractive option. They allow multiple neural networks of different types to be hosted on the same hardware, in parallel or sequence. Reconfigurability also grants the ability to morph into different micro-architectures to meet varying power-performance constraints. In this context, the need for a reconfigurable non-linear computational unit has not been widely researched. In this work, we present a formal and comprehensive method to select the optimal fixed-point representation to achieve the highest accuracy against the floating-point implementation benchmark. We also present a novel design of an optimised reconfigurable arithmetic unit for calculating non-linear functions. The unit can be dynamically configured to calculate the sigmoid, hyperbolic tangent, and exponential function using the same underlying hardware. We compare our work with the state-of-the-art and show that our unit can calculate all three functions without loss of accuracy

OROGRAPHIC EFFECT ON HEAVY RAINFALL IN CHALKIDIKI PENINSULA (GREECE) INDUCED BY A MEDITERRANEAN COLD FRONT: A CASE STUDY ON 7 to 8 OF OCTOBER 2000

Abstract. The exceptional heavy rainfall, in Chalkidiki peninsula-Greece, of 240 mm in a very short time period of 6 hours (380 mm in 24 hours) is analyzed. This area geographically located in the NW shores of the Aegean Sea, commonly has not the experience of frequent heavy rainfall events, and consequently the natural hydrographic network was not able to restrain this strong rainfall shock. Thus the result of the impact of this phenomenon was floods and damages in the properties of the residents with a very significant cost of hundredths thousands of Euros. This heavy rain phenomenon has been analyzed studying the role of the topography, the role of the nearby warm sea and the prevailing meteorological conditions resulting from the passage of the cold frond. This front was moving almost from south to north passing at first above the warm Aegean Sea surface, where it was supplied with huge amounts of water vapors, giving a total precipitable water value up to 32,0 mm. Then the very humid air forced uplifting, due to the intense relief of the mountainous peninsula, resulting to this torrential rainfall. All the relevant meteorological data and information about atmospheric instability, instability indexes and precipitable water available arising to from five upper air stations and the synoptic charts of surface, 850, 700, 500 and 300 hPa were analyzed in order to describe in details this heavy rain phenomenon

Terrorist incidents and tourism demand: Evidence from Greece

© 2017 Elsevier Ltd The purpose of this paper is to examine the impact of terrorism on tourism demand in Greece using monthly data from 1977 to 2012. We investigate whether this relationship is bidirectional and whether it exhibits long run persistence. Thus, we employ a large dataset of terrorist incidents and perform cointegration and long-run causality tests, correcting our data for cyclical seasonality and applying PCA to construct a terrorism proxy according to the severity of the incident. Our findings concur that terrorism has a significant negative impact on tourist arrivals to Greece and that causality is noted from terrorism to tourism only. The results suggest that authorities should establish firm measures against terrorism and that further actions should be taken to promote tourism, safety and security, as a response to terrorist incidents. Our study is, to the best our knowledge, the first to approach terrorism using a three-factor proxy with qualitative features

Anthelminthic Veterinary Medicines Interactions with the Soil Microbiota

Anthelminthics (AHs) are used to control gastrointestinal nematodes (GINs) in productive animals. They are rapidly excreted by animals, ending up in soil through direct deposition of animal dung or application of animal excreta as manures. Most environmental research on AHs has focused on their toxicity to aquatic organisms and soil fauna while their interactions with the soil microbiota, a key component of a functioning soil ecosystem, have been overlooked. In this article, we summarize current knowledge on the interactions of Ahs with the soil (micro) biota, we highlight recent evidence for the toxicity of AHs on soil microorganisms and discuss those results in the frame of the current environmental risk assessment (ERA) of veterinary medicines

Optimizing Self-Organizing Maps for Bacterial Genome Identification on Parallel Ultra-Low-Power Platforms

Pathogenic bacteria significantly threaten human health, highlighting the need for precise and efficient methods for swiftly identifying bacterial species. This paper addresses the challenges associated with performing genomics computations for pathogen identification on embedded systems with limited computational power. We propose an optimized implementation of Self-Organizing Maps (SOMs) targeting a parallel ultra-lowpower platform based on the RISC-V instruction set architecture. We propose two mapping methods for implementing the SOM algorithm on a parallel cluster, coupled with software techniques to improve the throughput. Orthogonally to parallelization, we investigate the impact of smaller-than-32-bit floating-point formats (smallFloats) on energy savings, precision, and performance. Our experimental results show that all smallFloat formats exhibit a 100% classification accuracy. The parallel variants achieve a speed-up of 1.98×, 3.79×, and 6.83× on 2, 4, and 8 cores, respectively. Comparing our design with a 16-bit fixed-point implementation on a coarse grain reconfigurable architecture (CGRA), the FP8 implementation achieves, on average, 1.42× energy efficiency, 1.51× speedup, and a 50% reduction in memory footprint compared to CGRA. Furthermore, FP8 vectorization increases the average speed-up by 2.5×

Methodology for Structured Data-Path Implementation in VLSI Physical Design: A Case Study

State-of-the-art modern microprocessor and domain-specific accelerator designs are dominated by data-paths composed of regular structures, also known as bit-slices. Random logic placement and routing techniques may not result in an optimal layout for these data-path-dominated designs. As a result, implementation tools such as Cadence’s Innovus include a Structured Data-Path (SDP) feature that allows data-path placement to be completely customized by constraining the placement engine. A relative placement file is used to provide these constraints to the tool. However, the tool neither extracts nor automatically places the regular data-path structures. In other words, the relative placement file is not automatically generated. In this paper, we propose a semi-automated method for extracting bit-slices from the Innovus SDP flow. It has been demonstrated that the proposed method results in 17% less density or use for a pixel buffer design. At the same time, the other performance metrics are unchanged when compared to the traditional place and route flow.publishedVersio

Terrorist incidents and tourism demand: evidence from Greece

The purpose of this paper is to examine the impact of terrorism on tourism demand in Greece using monthly data from 1977 to 2012. We investigate whether this relationship is bidirectional and whether it exhibits long run persistence. Thus, we employ a large dataset of terrorist incidents and perform cointegration and long-run causality tests, correcting our data for cyclical seasonality and applying PCA to construct a terrorism proxy according to the severity of the incident. Our findings concur that terrorism has a significant negative impact on tourist arrivals to Greece and that causality is noted from terrorism to tourism only. The results suggest that authorities should establish firm measures against terrorism and that further actions should be taken to promote tourism, safety and security, as a response to terrorist incidents. Our study is, to the best our knowledge, the first to approach terrorism using a three-factor proxy with qualitative features