882 research outputs found
Development and Assessment of Resource Management Solutions for Throughput Enhancement in a RIS-aided Mobile Network
No full textReconfigurable Intelligent Surfaces (RIS) are envisioned to become a pivotal transformative technology within the realm of 6G mobile networks. In this study, we introduce three heuristic algorithms designed to optimize radio resource management, ultimately enhancing throughput within a RIS-enhanced mobile network. Our findings demonstrate that the algorithm which holistically optimizes user scheduling, RIS-UE association, cell precoding matrices, and RIS configuration matrices outperforms alternative strategies.Moreover, our investigation delves into uncovering the most effective applications of RIS. This involves a thorough performance comparison of the algorithms across diverse scenarios, encompassing varying RIS deployment configurations (position and orientation), number of users in a network, and number of RIS elements. Additionally, we model the influence of blocker loss—characterized by blocker presence probability and strength—on throughput performance.In the wake of our study, it becomes evident that RIS exhibits the most promising potential in scenarios involving MU-MIMO configurations, whether within single-cell or multi-cell layouts, and for both indoor and outdoor user settings. However, for SU-MIMO cases, RIS-induced throughput enhancement manifests exclusively in single-cell layouts, and particularly benefits outdoor users in environments marked by substantial blocker strength.Electrical Engineering | Wireless Communication and Sensin
Collaborative Reverse Engineering Design Experiment Using PLM Solutions
No full textThe current climate of economic competition forces businesses to adapt to the expectations of their customers. To achieve this, in spite of the increasing complexity of mechanical systems, it becomes necessary, amongst other things, to reduce design time. Faced with new challenges, practices in design training must evolve to allow students to be mindful of these evolutions as well as to be able to manage projects in these new work environments. After presenting a state of the art of collaborative tools used in product design, our paper presents an experiment focusing on the reverse engineering of a complex mechanical product. This experiment was carried out between two centers of the Arts et Métiers ParisTech School of Engineering, located in Paris and Angers.Weanalyze the results obtained in this experiment and propose a collaborative environment that is well suited to our needs for design education, based on ‘‘Product Lifecycle Managament’’ (PLM) concepts. Finally, we present some modifications in collaborative design courses for our students, and we implement network modifications in order to significantly improve the ease of use of the design environment
Maritime Communications in RIS System for Inland Navigation
No full textThe article presents the VHF communications system architecture for inland navigation within the area of operation of the RIS-PL Centre. The author has described the communication system modules used in the RIS on the Lower Oder stretch and presented the relevant equipment specification. The present condition of the system has been described, taking into consideration the location of its components, both in the field and in the environment, of key importance for VHF communication. The feasibility of implementation of GMDSS subsystems for integrated navigational data transmission in maritime and inland navigation at the RIS-PL Centre has been discussed
VisuaLayered: Combined Visual Analysis of MA-XRF and RIS Data
No full textIn this work, we present VisuaLayered, the implementation of a combined analysis workflow for pigment identification. VisuaLayered is an integrated, interactive system that focuses on the combined visual analysis of Macro X-Ray Fluorescence (MA-XRF) and Reflectance Imaging Spectroscopy (RIS) data.Analysing paintings for pigment identification is relevant for many applications in the cultural heritage domain, such as conservation and restoration.Domain experts use non-invasive scanning techniques as an initial step in their analysis. Two such techniques are MA-XRF and RIS. They provide hyperspectral data on the elemental and molecular composition of pigments, respectively. Domain experts analyse these two complementary data modalities in order to determine the pigments present in the different paint layers of a painting. However, due to the size and high-dimensionality of these datasets, experts have problems with efficiently analysing the data. In general, they examine the two data modalities separately in the analysis workflow and use their knowledge to unify all the information without additional software support, as there is no integrated system that is designed specifically for the combined analysis of MA-XRF and RIS data.We worked in collaboration with domain experts from the Rijksmuseum, Amsterdam in order to design and implement VisuaLayered based on current domain practices. We use t-SNE for projecting the high-dimensional data into a two dimensional space, which the user can interactively explore in combination with other linked views in order to find connections between the two data modalities. With our system, experts can explore the spatial distribution and the correlation between pixels that have similar molecular and/or elemental compositions. Additionally, for the RIS data, we support endmember identification and analysis based on the pigments' spectral profiles. We tested the efficiency of our system with respect to the designed workflow in a case study evaluation with our collaborator. They successfully used VisuaLayered for the analysis of one painting and found the views combining the two data modalities very useful for better understanding the relation between them. Moreover, they were able to identify new pigments, that they missed when using existing software.Computer Science | Software Technolog
Visual Analysis of RIS Data for Endmember Selection
No full textReflectance Imaging Spectroscopy (RIS) is a hyperspectral imaging technique used for investigating the molecular composition of materials. It can help identify pigments used in a painting, which are relevant information for art conservation and history. For every scanned pixel, a reflectance spectrum is obtained and domain experts look for pure representative spectra, called endmembers, which could indicate the presence of particular pigments. However, the identification of endmembers can be a lengthy process, which requires domain experts to manually select pixels and visually inspect multiple spectra in order to find accurate endmembers that belong to the historical context of an investigated painting. We propose an integrated interactive visual-analysis workflow, that combines dimensionality reduction and linked visualizations to identify and inspect endmembers. Here, we present initial results, obtained in collaboration with domain experts.Team Matthias AlfeldComputer Graphics and Visualisatio
Electronic Reporting of Ships in the RIS System
No full textThis article presents the principles of data transmission and processing in a module of duplex transmission of messages as required by ship reporting in the RIS (River Information Services) system. Technical specification of messages intended for ship commanders is analyzed. Data standards in harmonized River Information Services on inland waterways are presented. Furthermore, the analysis covers message structures, encrypting in XML format for electronic reporting by ships. Finally, the author evaluates the advantages of introducing the RIS system for the safety of inland vessel traffic and the effect of the system on environmental protection
Countercyclical currency risk premia
No full textWe describe a novel currency investment strategy, the ‘dollar carry trade,’ which delivers large excess returns, uncorrelated with the returns on well-known carry trade strategies. Using a no-arbitrage model of exchange rates we show that these excess returns compensate U.S. investors for taking on aggregate risk by shorting the dollar in bad times, when the U.S. price of risk is high. The countercyclical variation in risk premia leads to strong return predictability: the average forward discount and U.S. industrial production growth rates forecast up to 25% of the dollar return variation at the one-year horizon. The estimated model implies that the variation in the exposure of U.S. investors to worldwide risk is the key driver of predictability. Keywords: Exchange rates; Forecasting; Ris
Impact of multiple RIS on channel characteristics: An experimental validation in Ka band
No full textInternational audienceIn this work, we present the results of an experi-mental validation of the use of multiple Reconfigurable Intel-ligent Surfaces (RISs) in indoor scenarios. The setup employs a Transmitting and a Reflecting RIS in the Ka band with more than 400 elements each. Two different 1-bit Unit Cell (UC) based on PIN -diode technologies have been designed to realize the RISs. The Transmitting RIS (T-RIS) is used on the Base Station (BS) side to perform steering towards the User Equipment (UE), or the Reflecting RIS (R-RIS) acting as extender. The channel responses are analysed over a wide band (25–35 GHz) to investigate the impact of the phase distribution over RISs, as well as the antenna employed on the BS or UE side. Finally, the Multi Path Components (MPCs) in different Line of Sight and Obstructed Line of Sight, are estimated by means of space-alternating generalized expectation-maximization (SAGE) wideband algorithm, and analysed to highlight the use of RISs
A database and analysis of bridges clogged by floating debris during the 2021 floods
No full textGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Hydraulic Structures and Flood Ris
Discussion of "transverse Nonuniformity of Air-Water Flow and Lateral Wall Effects in Quasi-Two-Dimensional Hydraulic Jump"
No full textGreen Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Hydraulic Structures and Flood Ris
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