676 research outputs found
Donadoni E., Baccarelli M., De Carli M., 2018, “Piazza Vittorio Emanuele II a Salò e la ricomposizione del suo centro storico” in Urbanistica Informazioni, n° 278 s.i, atti della XI Giornata Studi INU “interruzioni, intersezioni, condivisioni, sovrapposizioni. Nuove prospettive per il territorio”, ISSN 0392-5005
No full textConditionally Optimal Minimum-Delay Scheduling for Bursty Traffic Over Fading Channels
No full textNext-generation wireless networks for personal communication services should be designed to transfer delay-sensitive bursty-traffic flows over energy-limited buffer-equipped faded connections. In this application scenario, a still-open question concerns the closed-form design of scheduling policies minimizing the average transfer delay under constraints on both average and peak energies. Since, in this paper, both queue and link states may assume finite, countable infinite, or even uncountable infinite values, we cannot resort to dynamic programming to solve the aforementioned minimization problem. The key point of the (somewhat) novel approach that we follow consists of the minimization (on a per-step basis) of the queue length averaged over the fading statistics and conditioned on the queue occupancy at the previous step when two energy constraints are considered. The first one is on the allowed peak energy, and the second one is on the available average energy conditioned on the current queue occupancy. The resulting optimal scheduler operates cross layer, meaning that it allocates step-by-step energy on the basis of both current queue and link states. We prove that, under the considered energy constraints, the scheduler retains two optimality properties. First, its stability region is the maximal admissible one. Second, the scheduler also minimizes the unconditional average queue length. The numerical tests that have been carried out corroborate these optimality properties and give insight about scheduler performance under heavy-tailed distributed input traffic, such as that generated by variable-bit-rate (VBR) media encoders
Trasfo_mace. Ipotesi di trasformazione e riuso per l'ex Macello di Milano
No full textIl volume presenta gli esiti dell’attività progettuale del Laboratorio di Progettazione Architettonica e Urbana coordinato da Marco Lucchini e Marco Baccarelli, attivo presso il Corso di Laurea Magistrale (PSPA Interni) della Scuola AUIC del Politecnico di Milano che ha affrontato, nell’anno accademico 2017/18, il tema della riqualificazione dell’Ex Macello di Milano. Si tratta di progetti di trasformazione sviluppati dalla scala urbana a quella architettonica assumendo come tema il progetto della casa. Inoltre, sono presentate due tesi di Laurea Magistrale che, con approcci diversi, hanno affrontato anch’esse la riqualificazione dell’ex Macello.
L’attività di progettazione, sviluppata nel quadro della didattica, è stata l’occasione per una più ampia riflessione sui temi della progettazione urbana nelle aree dismesse, delle relazioni tra casa e città come strumento di trasformazione del tessuto urbano e del riuso, come alternativa alla demolizione delle preesistenze.
Ogni pratica progettuale, compresa quella didattica, ha necessità di un supporto teorico in base al quale il progetto esercita un ruolo critico. Di conseguenza la presentazione dei progetti è anticipata da alcuni saggi scritti da Marco Baccarelli, Isabella Inti, Beatrice Benatti, E. Zobbi, M. Zangrande finalizzati a porre quelle istanze che possono far nascere una dialettica tra pensiero e azione progettuale
Energy-Efficient Adaptive Resource Management for Real-Time Vehicular Cloud Services
No full textProviding real-time cloud services to Vehicular Clients (VCs) must cope with delay and delay-jitter issues. Fog computing is an emerging paradigm that aims at distributing small-size self-powered data centers (e.g., Fog nodes) between remote Clouds and VCs, in order to deliver data-dissemination real-time services to the connected VCs. Motivated by these considerations, in this paper, we propose and test an energy-efficient adaptive resource scheduler for Networked Fog Centers (NetFCs). They operate at the edge of the vehicular network and are connected to the served VCs through Infrastructure-to-Vehicular (I2V) TCP/IP-based single-hop mobile links. The goal is to exploit the locally measured states of the TCP/IP connections, in order to maximize the overall communication-plus-computing energy efficiency, while meeting the application-induced hard QoS requirements on the minimum transmission rates, maximum delays and delay-jitters. The resulting energy-efficient scheduler jointly performs: (i) admission control of the input traffic to be processed by the NetFCs; (ii) minimum-energy dispatching of the admitted traffic; (iii) adaptive reconfiguration and consolidation of the Virtual Machines (VMs) hosted by the NetFCs; and, (iv) adaptive control of the traffic injected into the TCP/IP mobile connections. The salient features of the proposed scheduler are that: (i) it is adaptive and admits distributed and scalable implementation; and, (ii) it is capable to provide hard QoS guarantees, in terms of minimum/maximum instantaneous rates of the traffic delivered to the vehicular clients, instantaneous rate-jitters and total processing delays. Actual performance of the proposed scheduler in the presence of: (i) client mobility; (ii) wireless fading; and, (iii) reconfiguration and consolidation costs of the underlying NetFCs, is numerically tested and compared against the corresponding ones of some state-of-the-art schedulers, under both synthetically generated and measured real-world workload traces
Optimal MIMO UWB-IR Transceiver for Nakagami-fading Poisson-Arrivals
No full textIn this contribution, we develop a (novel) family of Multiple-Input Multiple-Output (MIMO) UWB Impulse-Radio (UWB-IR) transceivers for Orthogonal PPM-modulated (OPPM) coded transmissions over (baseband) multipath-faded MIMO channels. To by-pass expensive channel-estimation procedures, the MIMO channel path-gains are assumed to he fully unknown at the receiver. Thus, according to the UWB-IR. statistical channel-models currently reported in the literature for both indoor/ outdoor application scenarios, we develop and analyze three versions of the resulting noncoherent transceiver, that are optimal for Nakagami, Gaussian, and Log-normal distributed channel-gains, respectively. As dictated by the Saleh-Valenzuela (SV) UWB model, the resulting noncoherent Maximum-Likelihood (ML) Decoder explicitly accounts for the Poisson-distribution of the path-arrivals. Hence, after analytically evaluating the performance of the proposed noncoherent transceiver via suitable versions of the Union-Chernoff bound, we prove that the family of Space-Time OPPM (STOPPM) recently presented in the Literature is able to attain full-diversity in the considered multipath-affected application scenario. To corroborate the carried out performance analysis, we report several numerical results supporting both the medium/ long coverage ranges attained by the proposed STOPPM-coded noncoherent transceiver, and its performance robusta against the degrading effects induced by Inter-Pulse-Interference (IPI), spatially-correlated multipath fading and mistiming. © 2008 Academy Publisher
Multi-Antenna Noncoherent ML Synchronization for UWB-IR Faded Channels
No full textThis contribution focuses on the maximum likelihood (ML) noncoherent synchronization of multi-antenna transceivers working in faded environments and employing ultra-wideband impulse radio (UWB-IR) transmit technology. In particular, the Cramer-Rao bound (CRB) is derived for the general case of multiple input multiple output (MIMO) UWB-IR systems and used to compare the ultimate performance of three basic transmit schemes, thereinafter referred to as single input multiple output (SIMO), MIMO equal signaling (MIMO-ES), and MIMO orthogonal signaling (MIMO-OS) ones. Thus, the noncoherent ML synchronizer is developed for the better performing transmit scheme (i.e., the SIMO one) and its performance is evaluated under both signal acquisition and tracking operating conditions. The performance gain in the synchronization of UWB-IR signals arising by the utilization of the multi-antenna technology is also evaluated. © 2006 KICS
A new family of optimized Orthogonal Space-Time Codes for PPM-based MIMO Systems with Imperfect channel estimates
No full textIn this contribution, we develop a single Multiple-Input Multiple Output (MIMO) transceiver for Orthogonal PPM (OPPM) data transmitted over (baseband) faded MIMO channels with a priori unknown path-gains. The signaling-scheme we adopt allows to equip the Maximum-Likelihood receiver with reliable estimates of the (possibly time-varying) MIMO channel, without reducing the conveyed information throughput. Hence, after evaluating the performance of the proposed transceiver via a suitable version of the Union-Chernoff Bound, we introduce a novel family of unitary orthogonal Space-Times Block Codes (e.g., the Space-Time OPPM codes), that are able to attain both maximum diversity and coding gains. Afterwards, we present closed-form formulas for evaluating the SNR loss induced by mistiming effects possibly impairing the received signals. Lastly, we report several numerical results supporting both the medium/long coverage ranges attained by the proposed transceiver in outdoor applications and its performance robustness against correlated channel fading, mistiming effects and degradation induced by dense-multipath fading. © 2007 Springer Science+Business Media, LLC
Excitation of a periodic microstrip line through a nonperiodic vertical current
No full textFinalista nella competizione "EuMC Young Engineer Prize
Parallel hardware implementation of RADAR electronics equipment for a LASER inspection system
No full textAn amplitude modulated laser radar has been developed by the Italian Agency for New Technologies, Energy and the Environment for periodic in-vessel inspection in large fusion machines (International Thermonuclear Experimental Reactor). The system is able to obtain a complete three-dimensional mapping of the in-vessel surface. A first digital signal processing system was developed to modulate the laser beam and to detect both the amplitude of the backscattered light and the phase difference between it and the modulation signal. This system is based on commercial digital receiver and parallel digital signal processing boards on a VME bus. It reaches a speed of 100 K measures/s, showing good accuracy and stability. Starting from this, a further development has been done to increase the speed up to 2.328 M measures/s. Reaching the submicrosecond speed was necessary to implement the mathematical algorithm in a highly parallel hardware architecture using a field programmable gate array (FPGA). Based on the good results of the previously developed system, it was decided to maintain the same acquisition front-end though using the last release of analog-to-digital converters, to increase the operating frequency from 80 up to 200 MHz. The software algorithm previously used was completely redesigned and optimized to be used in the FPGA hardware architecture
- …
