Analysis of visitors’ mobility patterns through random walk in the Louvre Museum

This paper proposes a random walk model to analyze visitors' mobility patterns in a large museum. Visitors' available time makes their visiting styles different, resulting in dissimilarity in the order and number of visited places and in path sequence length. We analyze all this by comparing a simulation model and observed data, which provide us the strength of the visitors' mobility patterns. The obtained results indicate that shorter stay-type visitors exhibit stronger patterns than those with the longer stay-type, confirming that the former are more selective than the latter in terms of their visitation type.Comment: 16 pages, 5 figures, 4 table

Design of MW-Class Coaxial Gyrotron Cavities With Mode-Converting Corrugation Operating at the Second Cyclotron Harmonic

This article presents investigations on the design of coaxial gyrotron cavities with mode-converting corrugations, operating at the second harmonic of the electron cyclotron frequency with output power of the order of megawatts. The suppression of the competing modes interacting at the fundamental cyclotron frequency is achieved by the combination of a corrugated coaxial insert and mode-converting corrugation on the outer wall. The outer corrugation couples the key competing modes to lower order modes with reduced quality factor. The design steps, which form a generally applicable design procedure, are described in detail. As an illustrative example, the proposed procedure is used for the design of a cavity for a fusion-relevant, second-harmonic MW-class gyrotron, operating at 170 GHz with the TE 37,1837,18 mode. From the simulations, it is found that for the proposed design, this mode is excited with an output power of around/ ∼ 1.5 MW. Two additional paths for cavity optimization toward even higher output power are also presented

High-Frequency MW-class Coaxial Gyrotron Cavities Operating at the Second Cyclotron Harmonic

Second-harmonic operation of gyrotron oscillators offers the possibility to generate millimeter and submillimeter radiation at half the value of the magnetic field required for operation at the fundamental cyclotron frequency (first harmonic). However, being inherently weaker than the interaction at the first harmonic, high-power second-harmonic continuous-wave (CW) operation employing high-order modes faces strong mode competition from the first-harmonic competing modes. It is shown that coaxial cavities with a corrugated insert allow to drastically enhance the mode selectivity at the second harmonic and suppress the first-harmonic competitors in MW-class gyrotrons. Detailed design considerations for coaxial cavities are presented and specific cavity designs for various candidate operating modes are given. We demonstrate numerically, with multimode interaction simulations, stable second-harmonic CW generation of 2 MW output power at 170 GHz and 0.7 MW at 280 GHz, using high-order modes with eigenvalues > 100. The presented results show the possibility to design second-harmonic gyrotrons with cost-effective magnet systems and achieve MW-class CW operation at frequencies above 250 GHz

Design Strategies for Second Harmonic Gyrotrons in Nuclear Fusion Applications

Gyrotrons are high-power microwave sources that play an important role in the heating of plasmas for magnetically confined thermonuclear fusion applications. This paper presents a comprehensive study of two potential strategies for operating high-power megawatt-class fusion gyrotrons at the second harmonic of the electron cyclotron frequency which requires only half of the gyrotron cavity magnetic field. The first approach focuses on a coaxial cavity design that effectively suppresses fundamental competing modes, making it a robust solution for second harmonic operation. The second strategy discusses the injection of an external locking signal. Therefore, a quasi-optical mode converter was designed and tested capable of handling both, co- and counter-rotating modes

Experience-Driven Design of Ambiences for Future Pop Up Workspaces

Knowledge work is in transformation and new means for supporting workers’ wellbeing and productivity are needed. Pop Up workspaces are temporary and often social working environments where people can modify their environment to suit their current work mode. The aim of the present research was to explore the opportunities of future Pop Up workspaces, and specifically their technology-mediated ambiences that can provide meaningful experiences for the workers. We employed the Experience-Driven Design (EDD) approach to gain insights of the desired experiences in Pop Up workspaces. We first conducted three participatory group sessions to ideate experience types for Pop Up workspaces. We then run a multidisciplinary concepting workshop in which we designed concepts for technology-mediated ambiences. Five experience categories for worker mindsets were identified, namely Liberty, Fellowship, Determination, Retreat and Recovery. We present ambience concepts that utilise the mindsets and related target experiences, and how they can be supported by ambient technologies.acceptedVersionPeer reviewe

Athens by Sound

Architecture is not only that which is built. Architecture is made up of different aspects, both material and immaterial. The atmosphere, the sounds, the smells, the possibility of interaction between human bodies: these all constitute characteristics of space, characteristics that are assuming an increasing importance within architectural research worldwide. Within this field of thought about “Architecture Beyond Building”, we focus on one particular non-material spatial phenomenon that lies ‘beyond the built’: sound. We have created, thus, an interactive sonic map of Athens, which presents, in an unexpected way, fragments of the atmosphere of the city. What would a non-visual map look like? What would it feel like if you wandered within a forest of headphones, playing sounds from different places in Athens? How would it feel if you found yourself in a ‘map’ that only appeared when you walked in it? What would it be like if the map only appeared when you invited one more person to be with you? The Greek pavilion addresses these questions through an atmospheric interactive ‘game’, presenting fragments of sounds and visual sequences of Athens. The visitor recreates the space around him through his own presence and movement. The map appears only where he walks, and/or when he invites one more person to sit next to him. The bodies of the visitors react with one another and with the space itself, creating a dynamic, changing field. This walk in the pavilion takes you “out there”, through invisible Athens. The pavilion brings forth the aspects of architecture that are ‘beyond the material’: the ‘beyond the built’, the almost unreachable, elusive aspects of space, such as sound, non-visual senses, atmosphere. It challenges, thus, the limits of architecture, the limits of what can be mapped and re-located and what cannot. An edited collection by A. Karandinou, C. Achtypi, S. Giamarelos, including texts by: Ιntothepill, Katie Lloyd Thomas, Martin Parker, Panayiotis Tournikiotis, Mark Wigley, Dorian Wiszniewski, Leslie Kavanaugh, Stephen Cairns, Jonathan Hill, Vassilis Ganiatsas, Anastasios Kotsiopoulos, Constance Classen, Stavros Stavrides, Ole Bouman, William Mitchell, Richard Coyne, Neil Spiller, Kas Oosterhuis, Nora Schueler, Zissis Kotionis, Stelarc, Andreas Angelidakis, Aristide Antonas, Slavoj Žižek, Nikolaos Laskaris, Argyris Rokas, Andreas Kourkoulas, John Peponis, Yorgos Ioannou, Yorgos Tzirtzilakis, Konstantinos Vita, Dionyssis Kapsalis, United Visual Artists, Platon Rivellis, and Dimitris Filippidis. Contributors to the Greek National Participation to the 11th International Architecture Exhibition La Biennale di Venezia "Out there. Architecture beyond building" (2008) Organised by: Hellenic Ministry of Culture [yppo.gr] General Directorate of Modern Culture Directorate of Visual Arts Department for the Promotion of Contemporary Art Curators: Anastasia Karandinou Christina Achtypi Stylianos Giamarelos Video works by Intothepill net [intothepill.net] Artists: Yiannis Grigoriadis Yiannis Isidorou Lina Theodorou Sound Recording / Sound Design Dimitris Miyakis [movement.gr] Vangelis Lympouridis Exhibition Graphics / Catalogue Design Company [company-london.com] Design and Implementation of interactive environment 2monochannels [2monochannels.com] Audiovisual and interactive systems design / acoustic design / construction supervision Iraklis Lampropoulos Giorgos Lampropoulos Software programming Vassilis Boukis Electronic subsystem design Michail Kritsotakis Electrical Design Giorgos Satolias Interconnection of interactive elements Vangelis Lympouridis [inter-axions.com] Dimitris Miyakis Light design L+DG lighting architects [lightingdg.com] Thomas Gravanis Christina Frangeti Construction Gavrilos Michalis [gavrilos.gr] Digital printing Polichromo [polichromo.com] Translations Rachel Howard Nikos Masourides Catalogue photographs Intothepill – Internet video platform Catalogue published by futura publications Marketing communication Chryssa Vrouzi Communication associate Katerina Stamidi Photographer Cathy Cunliffe [cathycunliffeΑΤgmail.com] For their financial and material support for the Greek participation at the 11th International Exhibition of Architecture, La Biennale di Venezia, we express our deepest thanks to the sponsors: Alexander S. Onassis Public Benefit Foundation [onassis.gr] Akzonobel [akzonobel.com] Carteco - Architectural Materials & Design [carteco.gr] L+DG Lighting Architects [lightingdg.com] Plaisio [plaisio.gr] Polichromo Advertising Applications [polichromo.com] iGuzzini illuminazione [iguzzini.com] Diathlasis Architectural Lighting [diathlasis.gr

Conceptual design of a modular EC system for EU-Demo

The DEMO reactor studies within EUROfusion aim to develop a fusion power plant concept. The large Tokamak device needs an auxiliary heating power which, at the present stage, is provided by the Electron Cyclotron (EC) Heating system with up to 130 MW foreseen to reach different regions of plasma for heating, suppression of instabilities and possibly supporting ramp-up and ramp-down phases. The present conceptual design of the system is based on 2-MW coaxial-cavity gyrotron sources in development at IHM-KIT, a transmission line using both circular corrugated waveguides and a quasi-optical evacuated multi-beam transmission line, and mirror antennas located in the Equatorial port. In order to have a modular system, the sources are grouped in “clusters”, which power is combined in the quasi-optical transmission line, up to the Tokamak Building, where they are split and routed as single waveguides. In the launcher, they are combined together again on the launching mirrors, to save space for the apertures in the Breeding Blanket. The present EC system has a certain flexibility to adapt to changing design guidelines, as the foreseen transition to a lower DEMO aspect ratio. The system and the development status of each subsystem will be presented