Inhomogeneous metallic phase upon disordering a two dimensional Mott insulator

We find that isoelectronic disorder destroys the spectral gap in a Mott-Hubbard insulator in 2D leading, most unexpectedly, to a new metallic phase. This phase is spatially inhomogeneous with metallic behavior coexisting with antiferromagnetic long range order. Even though the Mott gap in the pure system is much larger than antiferromagnetic exchange, the spectral gap is destroyed locally in regions where the disorder potential is high enough to overcome the inter-electron repulsion thereby generating puddles where charge fluctuations are enhanced. With increasing disorder, these puddles expand and concomitantly the states at the Fermi energy get extended leading to a metallic phase. We discuss the implications of our results for experiments.Comment: (4 pages, 5 figures

Remote detection of boundary-layer transition by an optical system

This instrument development program was funded because of the urgent need to measure boundary-layer transition in wind tunnels. In the course of this development program, a prototype was designed, built, and tested. Recent transonic experiments in the Boeing Model Transonic Wind Tunnel show that the interferometer results correlate very well with sublimating chemical tests

The Modern State After Kant A Materialist Approach

This article proposes an encounter between Kant’s political doctrine and Marx’s materialist method. The primary aim of this materialist critique of Kant is to discern the structure that determines the specific mode of functioning of the modern state. The article starts with Kant’s conception of freedom and law and relates these concepts to his theory of history. In the first and second sections, Kant’s political doctrine is subject to a critical reversal that more closely engages with Marx’s critical materialist approach. The article then concludes upon a new, topological approach to the ternary structure involving the intersection of three “rings”—capitalist circulation, the state in its legal effective reality, and measured labor forces in production

The Modern State After Kant A Materialist Approach

This article proposes an encounter between Kant’s political doctrine and Marx’s materialist method. The primary aim of this materialist critique of Kant is to discern the structure that determines the specific mode of functioning of the modern state. The article starts with Kant’s conception of freedom and law and relates these concepts to his theory of history. In the first and second sections, Kant’s political doctrine is subject to a critical reversal that more closely engages with Marx’s critical materialist approach. The article then concludes upon a new, topological approach to the ternary structure involving the intersection of three “rings”—capitalist circulation, the state in its legal effective reality, and measured labor forces in production

Radio resource allocation for overlay D2D-based vehicular communications in future wireless networks

Mobilfunknetze der nächsten Generation ermöglichen einen weitverbreiteten Einsatz von Device-to-Device Kommunikation, der direkten Kommunikation zwischen zellularen Endgeräten. Für viele Anwendungsfälle zur direkten Kommunikation zwischen Endgeräten sind eine deterministische Latenz und die hohe Zuverlässigkeit von zentraler Bedeutung. Dienste zur direkten Kommunikation (D2D) für in der Nähe befindliche Endgeräte sind vielversprechend die hohen Anforderungen an Latenz und Zuverlässigkeit für zukünftige vertikale Anwendungen zu erfüllen. Eine der herausragenden vertikalen Anwendungen ist die Fahrzeugkommunikation, bei der die Fahrzeuge sicherheitskritische Meldungen direkt über D2D-Kommunikation austauschen, die dadurch zur Reduktion von Verkehrsunfällen und gleichzeitig von Todesfällen im Straßenverkehrt beiträgt. Neue Techniken zur effizienteren Zuweisung von Funkressourcen in der D2D-Kommunikation haben in letzter Zeit in Industrie und Wissenschaft große Aufmerksamkeit erlangt. Zusätzlich zur Allokation von Ressourcen, wird die Energieeffizienz zunehmend wichtiger, die normalerweise im Zusammenhang mit der Ressourcenallokation behandelt wird. Diese Dissertation untersucht verschiedener Ansätze der Funkressourcenzuweisung und Energieeffizienztechniken in der LTE und NR V2X Kommunikation. Im Folgenden beschreiben wir kurz die Kernideen der Dissertation. Meist zeichnen sich D2D-Anwendungen durch ein relativ geringes Datenvolumen aus, die über Funkressourcen übertragen werden. In LTE können diese Funkressourcen aufgrund der groben Granularität für die Ressourcenzuweisung nicht effizient genutzt werden. Insbesondere beim semi-persistenten Scheduling, bei dem eine Funkressource über einen längeren Zeitraum im Overlay D2D festgelegt wird, sind die Funkressourcen für solche Anwendungen nicht ausgelastet. Um dieses Problem zu lösen, wird eine hierarchische Form für das Management der Funkressourcen, ein sogenanntes Subgranting-Schema, vorgeschlagen. Dabei kann ein nahegelegener zellularer Nutzer, der sogenannte begünstigte Nutzer, ungenutzten Funkressourcen, die durch Subgranting-Signalisierung angezeigt werden, wiederzuverwenden. Das vorgeschlagene Schema wird bewertet und mit "shortening TTI", einen Schema mit reduzierten Sendezeitintervallen, in Bezug auf den Zellendurchsatz verglichen. Als nächster Schritt wird untersucht, wie der begünstigten Benutzer ausgewählt werden kann und als Maximierungsproblem des Zellendurchsatzes im Uplink unter Berücksichtigung von Zuverlässigkeits- und Latenzanforderungen dargestellt. Dafür wird ein heuristischer zentralisierter, d.h. dedizierter Sub-Granting-Radio-Ressource DSGRR-Algorithmus vorgeschlagen. Die Simulationsergebnisse und die Analyse ergeben in einem Szenario mit stationären Nutzern eine Erhöhung des Zelldurchsatzes bei dem Einsatz des vorgeschlagenen DSGRR-Algorithmus im Vergleich zu einer zufälligen Auswahl von Nutzern. Zusätzlich wird das Problem der Auswahl des begünstigten Nutzers in einem dynamischen Szenario untersucht, in dem sich alle Nutzer bewegen. Wir bewerten den durch das Sub-Granting durch die Mobilität entstandenen Signalisierungs-Overhead im DSGRR. Anschließend wird ein verteilter Heuristik-Algorithmus (OSGRR) vorgeschlagen und sowohl mit den Ergebnissen des DSGRR-Algorithmus als auch mit den Ergebnissen ohne Sub-Granting verglichen. Die Simulationsergebnisse zeigen einen verbesserten Zellendurchsatz für den OSGRR im Vergleich zu den anderen Algorithmen. Außerdem ist zu beobachten, dass der durch den OSGRR entstehende Overhead geringer ist als der durch den DSGRR, während der erreichte Zellendurchsatz nahe am maximal erreichbaren Uplink-Zellendurchsatz liegt. Zusätzlich wird die Ressourcenallokation im Zusammenhang mit der Energieeffizienz bei autonomer Ressourcenauswahl in New Radio (NR) Mode 2 untersucht. Die autonome Auswahl der Ressourcen wird als Verhältnis von Summenrate und Energieverbrauch formuliert. Das Ziel ist den Stromverbrauch der akkubetriebenen Endgeräte unter Berücksichtigung der geforderten Zuverlässigkeit und Latenz zu minimieren. Der heuristische Algorithmus "Density of Traffic-based Resource Allocation (DeTRA)" wird als Lösung vorgeschlagen. Bei dem vorgeschlagenen Algorithmus wird der Ressourcenpool in Abhängigkeit von der Verkehrsdichte pro Verkehrsart aufgeteilt. Die zufällige Auswahl erfolgt zwingend auf dem dedizierten Ressourcenpool beim Eintreffen aperiodischer Daten. Die Simulationsergebnisse zeigen, dass der vorgeschlagene Algorithmus die gleichen Ergebnisse für die Paketempfangsrate (PRR) erreicht, wie der sensing-basierte Algorithmus. Zusätzlich wird der Stromverbrauch des Endgeräts reduziert und damit die Energieeffizienz durch die Anwendung des DeTRA-Algorithmus verbessert. In dieser Arbeit werden Techniken zur Allokation von Funkressourcen in der LTE-basierten D2D-Kommunikation erforscht und eingesetzt, mit dem Ziel Funkressourcen effizienter zu nutzen. Darüber hinaus ist der in dieser Arbeit vorgestellte Ansatz eine Basis für zukünftige Untersuchungen, wie akkubasierte Endgeräte mit minimalem Stromverbrauch in der NR-V2X-Kommunikation Funkressourcen optimal auswählen können.Next-generation cellular networks are envisioned to enable widely Device-to-Device (D2D) communication. For many applications in the D2D domain, deterministic communication latency and high reliability are of exceptionally high importance. The proximity service provided by D2D communication is a promising feature that can fulfil the reliability and latency requirements of emerging vertical applications. One of the prominent vertical applications is vehicular communication, in which the vehicles disseminate safety messages directly through D2D communication, resulting in the fatality rate reduction due to a possible collision. Radio resource allocation techniques in D2D communication have recently gained much attention in industry and academia, through which valuable radio resources are allocated more efficiently. In addition to the resource allocation techniques, energy sustainability is highly important and is usually considered in conjunction with the resource allocation approach. This dissertation is dedicated to studying different avenues of the radio resource allocation and energy efficiency techniques in Long Term Evolution (LTE) and New Radio (NR) Vehicle-to-Everythings (V2X) communications. In the following, we briefly describe the core ideas in this study. Mostly, the D2D applications are characterized by relatively small traffic payload size, and in LTE, due to coarse granularity of the subframe, the radio resources can not be utilized efficiently. Particularly, in the case of semi-persistent scheduling when a radio resource is scheduled for a longer time in the overlay D2D, the radio resources are underutilized for such applications. To address this problem, a hierarchical radio resource management scheme, i.e., a sub-granting scheme, is proposed by which nearby cellular users, i.e., beneficiary users, are allowed to reuse the unused radio resource indicated by sub-granting signaling. The proposed scheme is evaluated and compared with shortening Transmission Time Interval (TTI) schemes in terms of cell throughput. Then, the beneficiary user selection problem is investigated and is cast as a maximization problem of uplink cell throughput subject to reliability and latency requirements. A heuristic centralized, i.e., dedicated sub-granting radio resource Dedicated Sub-Granting Radio Resource (DSGRR) algorithm is proposed to address the original beneficiary user selection problem. The simulation results and analysis show the superiority of the proposed DSGRR algorithm over the random beneficiary user selection algorithm in terms of the cell throughput in a scenario with stationary users. Further, the beneficiary user selection problem is investigated in a scenario where all users are moving in a dynamic environment. We evaluate the sub-granting signaling overhead due to mobility in the DSGRR, and then a distributed heuristics algorithm, i.e., Open Sub-Granting Radio Resource (OSGRR), is proposed and compared with the DSGRR algorithm and no sub-granting case. Simulation results show improved cell throughput for the OSGRR compared with other algorithms. Besides, it is observed that the overhead incurred by the OSGRR is less than the DSGRR while the achieved cell throughput is yet close to the maximum achievable uplink cell throughput. Also, joint resource allocation and energy efficiency in autonomous resource selection in NR, i.e. Mode 2, is examined. The autonomous resource selection is formulated as a ratio of sum-rate and energy consumption. The objective is to minimize the energy efficiency of the power-saving users subject to reliability and latency requirements. A heuristic algorithm, density of traffic-based resource allocation (DeTRA), is proposed to solve the problem. The proposed algorithm splits the resource pool based on the traffic density per traffic type. The random selection is then mandated to be performed on the dedicated resource pool upon arrival of the aperiodic traffic is triggered. The simulation results show that the proposed algorithm achieves the same packet reception ratio (PRR) value as the sensing-based algorithm. In addition, per-user power consumption is reduced, and consequently, the energy efficiency is improved by applying the DeTRA algorithm. The research in this study leverages radio resource allocation techniques in LTE based D2D communications to be utilized radio resources more efficiently. In addition, the conducted research paves a way to study further how the power-saving users would optimally select the radio resources with minimum energy consumption in NR V2X communications

Egocentric Vision-based Future Vehicle Localization for Intelligent Driving Assistance Systems

Predicting the future location of vehicles is essential for safety-critical applications such as advanced driver assistance systems (ADAS) and autonomous driving. This paper introduces a novel approach to simultaneously predict both the location and scale of target vehicles in the first-person (egocentric) view of an ego-vehicle. We present a multi-stream recurrent neural network (RNN) encoder-decoder model that separately captures both object location and scale and pixel-level observations for future vehicle localization. We show that incorporating dense optical flow improves prediction results significantly since it captures information about motion as well as appearance change. We also find that explicitly modeling future motion of the ego-vehicle improves the prediction accuracy, which could be especially beneficial in intelligent and automated vehicles that have motion planning capability. To evaluate the performance of our approach, we present a new dataset of first-person videos collected from a variety of scenarios at road intersections, which are particularly challenging moments for prediction because vehicle trajectories are diverse and dynamic.Comment: To appear on ICRA 201

Evolution of the galaxy luminosity function in progenitors of fossil groups

Using the semi-analytic models based on the Millennium simulation, we trace back the evolution of the luminosity function of galaxies residing in progenitors of groups classified by the magnitude gap at redshift zero. We determine the luminosity function of galaxies within $0.25R_{200}, 0.5R_{200}$, and $R_{200}$ for galaxy groups/clusters. The bright end of the galaxy luminosity function of fossil groups shows a significant evolution with redshift, with changes in $M^*$ by $\sim$ 1-2 mag between $z\sim0.5$ and $z=0$ (for the central $0.5R_{200}$), suggesting that the formation of the most luminous galaxy in a fossil group has had a significant impact on the $M^{*}$ galaxies e.g. it is formed as a result of multiple mergers of the $M^{*}$ galaxies within the last $\sim5$ Gyr. In contrast, the slope of the faint end, $\alpha$, of the luminosity function shows no considerable redshift evolution and the number of dwarf galaxies in the fossil groups exhibits no evolution, unlike in non-fossil groups where it grows by $\sim25-42\%$ towards low redshifts. In agreement with previous studies, we also show that fossil groups accumulate most of their halo mass earlier than non-fossil groups. Selecting the fossils at a redshift of 1 and tracing them to a redshift 0, we show that $80\%$ of the fossil groups ($10^{13} M_{\odot} h^{-1}<M_{200}<10^{14} M_{\odot} h^{-1}$) will lose their large magnitude gaps. However, about $40\%$ of fossil clusters ($M_{200}>10^{14} M_{\odot} h^{-1}$) will retain their large gaps.Comment: Accepted for publication in A&A. 13 pages, 15 figure

Open sub-granting radio resources in overlay D2D-based V2V communications

Capacity, reliability, and latency are seen as key requirements of new emerging applications, namely vehicle-to-everything (V2X) and machine-type communication in future cellular networks. D2D communication is envisaged to be the enabler to accomplish the requirements for the applications as mentioned earlier. Due to the scarcity of radio resources, a hierarchical radio resource allocation, namely the sub-granting scheme, has been considered for the overlay D2D communication. In this paper, we investigate the assignment of underutilized radio resources from D2D communication to device-to-infrastructure communication, which are moving in a dynamic environment. The sub-granting assignment problem is cast as a maximization problem of the uplink cell throughput. Firstly, we evaluate the sub-granting signaling overhead due to mobility in a centralized sub-granting resource algorithm, dedicated sub-granting radio resource (DSGRR), and then a distributed heuristics algorithm, open sub-granting radio resource (OSGRR), is proposed and compared with the DSGRR algorithm and no sub-granting case. Simulation results show improved cell throughput for the OSGRR compared with other algorithms. Besides, it is observed that the overhead incurred by the OSGRR is less than the DSGRR while the achieved cell throughput is yet close to the maximum achievable uplink cell throughput