Fully Parallel Hyperparameter Search: Reshaped Space-Filling

Space-filling designs such as scrambled-Hammersley, Latin Hypercube Sampling and Jittered Sampling have been proposed for fully parallel hyperparameter search, and were shown to be more effective than random or grid search. In this paper, we show that these designs only improve over random search by a constant factor. In contrast, we introduce a new approach based on reshaping the search distribution, which leads to substantial gains over random search, both theoretically and empirically. We propose two flavors of reshaping. First, when the distribution of the optimum is some known $P_0$, we propose Recentering, which uses as search distribution a modified version of $P_0$ tightened closer to the center of the domain, in a dimension-dependent and budget-dependent manner. Second, we show that in a wide range of experiments with $P_0$ unknown, using a proposed Cauchy transformation, which simultaneously has a heavier tail (for unbounded hyperparameters) and is closer to the boundaries (for bounded hyperparameters), leads to improved performances. Besides artificial experiments and simple real world tests on clustering or Salmon mappings, we check our proposed methods on expensive artificial intelligence tasks such as attend/infer/repeat, video next frame segmentation forecasting and progressive generative adversarial networks

Development of Wireless Techniques in Data and Power Transmission - Application for Particle Physics Detectors

Wireless techniques have developed extremely fast over the last decade and using them for data and power transmission in particle physics detectors is not science- fiction any more. During the last years several research groups have independently thought of making it a reality. Wireless techniques became a mature field for research and new developments might have impact on future particle physics experiments. The Instrumentation Frontier was set up as a part of the SnowMass 2013 Community Summer Study [1] to examine the instrumentation R&D for the particle physics research over the coming decades: {\guillemotleft} To succeed we need to make technical and scientific innovation a priority in the field {\guillemotright}. Wireless data transmission was identified as one of the innovations that could revolutionize the transmission of data out of the detector. Power delivery was another challenge mentioned in the same report. We propose a collaboration to identify the specific needs of different projects that might benefit from wireless techniques. The objective is to provide a common platform for research and development in order to optimize effectiveness and cost, with the aim of designing and testing wireless demonstrators for large instrumentation systems

The vertical distribution of Cs-137 in Bavarian forest soils.

Persistently high activity concentrations of radioactive Cs-137 (T (1/2) = 30.17 a) in various animals and fruits originating from Bavarian forest ecosystems suggest that the contamination of soils in these ecosystems is still critical even decades after the severe inputs following the Chernobyl nuclear accident. Aware of the fact, that such inputs are a global threat that can re-emerge at any time, a new monitoring network was established in cooperation with the Bavarian State Ministry of the Environment and Public Health, to enhance the value of long-term radioprotection strategies in forests. Based on the investigation of 48 forest sites throughout the entire state territory, the project delivers a total of 889 gamma spectrometric records and demonstrates the current Cs-137 contamination situation of Bavarian forest soils, providing a valuable update on the residual contamination levels and thus a comprehensive inventory for any future radioprotection management. First results of this project are presented hereby. The total Cs-137 areal activity densities in Bavarian forest soils currently vary between 640 and 61,166 Bq m(-)A(2), with the peak areal activity density of each profile being located in the uppermost, humus rich mineral A-horizon in 68 % of all cases. Moreover, the results detect a positive correlation of humus thickness and relative areal Cs-137 activity density in humus horizons (RA(2)A = 0.50), validating previous findings on that topic by means of a very comprehensive data set across 2.56 Mio ha forest stands by showing that humus bodies > 7.5 cm still contain at least 50 % of the total areal topsoil activity density

A D-band high-gain antenna module combining an in-package active feed and a flat discrete lens

International audienceThis paper presents the design and experimental characterization of a high-gain D-band antenna module for highcapacity short-range links. The system comprises an active feed and a flat discrete lens. The active feed integrates a 45-nm CMOS two-channel transmitter, a diplexer and a four-element patch array on a low-cost laminate. This antenna-in-package excites a 48×48 planar lens which is designed using 16 different unit-cells and is optimized to collimate a broadside beam. The module operates over an 11.6% fractional bandwidth, between 139.4 GHz and 156.6 GHz, and delivers a peak effective isotropic power of 17 dBm

Channel bonding transceivers for efficient 100 Gb/s and beyond wireless and plastic wave guide communications

International audienceHigh-data rate communications in the range of 100 Gbps require handling larger RF bandwidths in frequency bands beyond 100 GHz. The architecture of the transceiver should be reconsidered compared with classical approaches in order to optimize the power consumption. Channel bonding architectures combine relatively low baseband bandwidth inputs with power combining and up-conversion stages in order to obtain a large bandwidth at RF. In this paper, some implementations of energy efficient transceivers using this operating principle at D-band (around 140 GHz) will be presented. Wireless communications and plastic waveguide links are demonstrated with data rates of several tens of Gbps and energy consumption in the order of a few tens of pJ/bit

Fully Parallel Hyperparameter Search: Reshaped Space-Filling

International audienceSpace-filling designs such as Low Discrepancy Sequence (LDS), Latin Hypercube Sampling (LHS) and Jittered Sampling (JS) were proposed for fully parallel hyperparameter search, and were shown to be more effective than random and grid search. We prove that LHS and JS outperform random search only by a constant factor. Consequently, we introduce a new sampling approach based on the reshaping of the search distribution, and we show both theoretically and numerically that it leads to significant gains over random search. Two methods are proposed for the reshaping: Recentering (when the distribution of the optimum is known), and Cauchy transformation (when the distribution of the optimum is unknown). The proposed methods are first validated on artificial experiments and simple real-world tests on clustering and Salmon mappings. Then we demonstrate that they bring performance improvement in a wide range of expensive artificial intelligence tasks, namely attend/infer/repeat, video next frame segmentation forecasting and progressive generative adversarial networks

6G: The next frontier: From holographic messaging to artificial intelligence using subterahertz and visible light communication

With its ability to provide a single platform enabling a variety of services, such as enhanced mobile broadband communications, virtual reality, automated driving, and the Internet of Things, 5G represents a breakthrough in the design of communication networks. Nevertheless, considering the increasing requests for new services and predicting the development of new technologies within a decade, it is already possible to envision the need to move beyond 5G and design a new architecture incorporating innovative technologies to satisfy new needs at both the individual and societal levels. The goal of this article is to motivate researchers to move to a sixth generation (6G) of mobile communication networks, starting from a gap analysis of 5G and predicting a new synthesis of near-future services like holographic communications, high-precision manufacturing, a pervasive introduction of artificial intelligence (AI), and the integration of new technologies, such as subterahertz or visible light communication (VLC), in a truly 3D coverage scenario. Such a framework will incorporate terrestrial and aerial radio access points to bring cloud functionalities where and when needed on demand

Silicon interposer with integrated antenna array for millimeter-wave short-range communications

International audienceA 60 GHz cavity-backed antenna array integrated on high-resistivity silicon is demonstrated. The antenna design makes use of Through-Silicon-Vias (TSV), silicon micromachining, and wafer-to-wafer bonding to meet the bandwidth and radiation gain requirements for short-range multi-Gbps communications. The fabrication process is presented. Simulated and experimental results show that the antenna element covers easily the 57–66 GHz standard band with good impedance matching and more than 5 dBi of gain. Several fixed-beam four-element antenna arrays demonstrate the capabilities for beam-steering across a range up to ±60°