Improving Urban Traffic Mobility via a Versatile Quantum Annealing Model

The growth of cities and the resulting increase in vehicular traffic poses significant challenges to the environment and citizens' Quality of Life. To address these challenges, a new algorithm has been proposed that leverages the Quantum Annealing paradigm and D-Wave's machines to optimize the control of traffic lights in cities. The algorithm considers traffic information collected from a wide urban road network to define activation patterns that holistically reduce congestion. An in-depth analysis of the model's behaviour has been conducted by varying its main parameters. Robustness tests have been performed on different traffic scenarios, and a thorough discussion on how to configure D-Wave's quantum annealers for optimal performance is presented. Comparative tests show that the proposed model outperforms traditional control techniques in several traffic conditions, effectively containing critical congestion situations, reducing their presence, and preventing their formation. The results obtained put in evidence the state-of-the-art of these quantum machines, their actual capabilities in addressing the problem, and opportunities for future applications

Beyond von Neumann architectures: exploring algorithmic opportunities via Octantis

Today, one of the problems the scientific community is called upon to tackle is the well-known von Neumann bottleneck , which concerns the limitation in the bandwidth between the CPU and memory in a digital electronic system. Among the various solutions under study, the concept of Logic-in-Memory (LiM) has been proposed: a memory device that embeds simple computational elements between the different cells to define a distributed processing system. The present work introduces an extended version of Octantis, a novel open-source software useful for exploring LiM architectures. To achieve this goal, the internal structure of Octantis takes inspiration from the one of standard High-Level Synthesis tools, distinguishing itself from them for the target topology addressed. It analyses user-defined standard-C algorithms and determines which LiM architecture would be best suited to implement it. At its output, the tool provides a VHDL description of the synthesised circuit along with a custom test-bench. The earlier version of Octantis efficiently synthesised rather simple user-defined C algorithms. The version discussed here has been improved by extending the allowed complexity of input C-codes, like addressing nested loops and non-trivial data dependencies, and introducing hardware-specific optimisations to meet resource constraints. Several case studies have been considered to validate the newly implemented techniques and to analyse the capabilities of the tool in implementing data-intensive algorithms. The results demonstrate that Octantis can produce architectures that comply with the LiM topology while significantly reducing the exploration space to meet specific hardware requirements, such as memory dimensions and maximum logic integration. This methodology provides initial insights into potential LiM units that can be adopted in customised designs, making it a valuable tool in researching alternative electronic devices

Virtual Network Function Embedding with Quantum Annealing

In recent years, the growing number of devices connected to the internet led network operators to continuously expand their own infrastructures. In order to simplify this scaling process, the research community is currently investigating the opportunity to move the complexity from a hardware to a software domain, through the introduction of a new paradigm, called Network Functions Virtualisation (NFV). It considers standard hardware platforms where many virtual instances are allocated to implement specific network services. However, despite the theoretical benefits, the mapping of the different virtual instances to the available physical resources represents a complex problem, difficult to be solved classically. The present work proposes a Quadratic Unconstrained Binary Optimisation (QUBO) formulation of this embedding process, exploring the implementation possibilities on D-Wave’s Quantum Annealers. Many test cases, with realistic constraints, have been considered to validate and characterise the potential of the model, and the promising results achieved are discussed throughout the document. The technical discussion is enriched with comparisons of the results obtained through heuristic algorithms, highlighting the strengths and the limitations in the resolution of the QUBO formulation proposed on current quantum machines

Octantis: An Exploration Tool for Beyond von Neumann architectures

Nowadays, the modern electronic systems are facing an important limitation in terms of performance, known as von Neumann bottleneck. It affects the communications between two crucial elements, the CPU and the memory, which suffer from a saturation in bandwidth. Many solutions are currently under investigation and among them the concept of Logic-in-Memory (LiM) has been introduced: a memory enriched in its array of computational elements which enable the implementation of a flexible distributed processing system. The current work introduces Octantis, a High-Level Synthesizer useful for the exploration of LiM architectures. The proposed software analyzes an input algorithm described in standard C language and identifies which LiM architecture would implement it better. At its output, the synthesized solution is provided together with a test-bench, to properly characterize it, in terms of performance, spatial occupation and power consumption. Many algorithms have been successfully synthesized by Octantis and some of the results achieved will be discussed along the document

Preface of the 31st Italian Symposium on Advanced Database Systems

This volume contains the proceedings of the 31st Italian Symposium on Advanced Database Systems (SEBD - Sistemi Evoluti per Basi di Dati), held in Galzinagno Terme (Padua, Italy) from 2 to 5 July 2023.</p

Preface of the 31st Italian Symposium on Advanced Database Systems

This volume contains the proceedings of the 31st Italian Symposium on Advanced Database Systems (SEBD - Sistemi Evoluti per Basi di Dati), held in Galzinagno Terme (Padua, Italy) from 2 to 5 July 2023.</p

Test and Modeling of the Hydraulic Performance of High-Efficiency Cooling Configurations for Gyrotron Resonance Cavities

The design and manufacturing of different full-size mock-ups of the resonance cavity of gyrotrons, relevant for fusion applications, were performed according to two different cooling strategies. The first one relies on mini-channels, which are very promising in the direction of increasing the heat transfer in the heavily loaded cavity, but which could face an excessively large pressure drop, while the second one adopts the solution of Raschig rings, already successfully used in European operating gyrotrons. The mock-ups, manufactured with conventional techniques, were hydraulically characterized at the Thales premises, using water at room temperature. The measured pressure drop data were used to validate the corresponding numerical computational fluid dynamics (CFD) models, developed with the commercial software STAR-CCM+ (Siemens PLM Software, Plano TX, U.S.A.) and resulting in excellent agreement with the test results. When the validated models were used to compare the two optimized cooling configurations, it resulted that, for the same water flow, the mini-channel strategy gave a pressure drop was two-fold greater than that of the Raschig rings strategy, allowing a maximum flow rate of 1 &times; 10&minus;3 m3/s to meet a maximum allowable pressure drop of 0.5 MPa

Características da glândula mamária de ovinos relacionadas à infecção pelo vírus Maedi-Visna no Rio Grande do Sul

04