1,721,115 research outputs found
Incentive compatibility in kidney exchange problems
No full textThe problem of kidney exchanges shares common features with the classical problem of exchange of indivisible goods studied in the mechanism design literature, while presenting additional constraints on the size of feasible exchanges. The solution of a kidney exchange problem can be summarized in a mapping from the relevant underlying characteristics of the players (patients and their donors) to the set of matchings. The goal is to select only matchings maximizing a chosen welfare function. Since the final outcome heavily depends on the private information in possess of the players, a basic requirement in order to reach efficiency is the truthful revelation of this information. We show that for the kidney exchange problem, a class of (in principle) efficient mechanisms does not enjoy the incentive compatibility property and therefore is subject to possible manipulations made by the players in order to profit of the misrepresentation of their private information. © 2008 Springer Science+Business Media, LLC
Flow Assignment and Processing on a Distributed Edge Computing Platform
No full textThe evolution of telecommunication networks toward the fifth generation of mobile services (5G), along with the increasing presence of cloud-native applications, and the development of Cloud and Mobile Edge Computing (MEC) paradigms, have opened up new opportunities for the monitoring and management of logistics and transportation. We address the case of distributed streaming platforms with multiple message brokers to develop an optimization model for the real-time assignment and load balancing of event streaming generated data traffic among Edge Computing facilities. The performance indicator function to be optimised is derived by adopting queuing models with different granularity (packet- and flow-level) that are suitably combined. A specific use case concerning a logistics application is considered and numerical results are provided to show the effectiveness of the optimisation procedure, also in comparison to a “static” assignment proportional to the processing speed of the brokers
IoT and UAV Integration in 5G Hybrid Terrestrial-Satellite Networks
No full textThe Fifth Generation of Mobile Communications (5G) will lead to the growth of use cases demanding higher capacity and a enhanced data rate, a lower latency, and a more flexible and scalable network able to offer better user Quality of Experience (QoE). The Internet of Things (IoT) is one of these use cases. It has been spreading in the recent past few years, and it covers a wider range of possible application scenarios, such as smart city, smart factory, and smart agriculture, among many others. However, the limitations of the terrestrial network hinder the deployment of IoT devices and services. Besides, the existence of a plethora of different solutions (short vs. long range, commercialized vs. standardized, etc.), each of them based on different communication protocols and, in some cases, on different access infrastructures, makes the integration among them and with the upcoming 5G infrastructure more difficult. This paper discusses the huge set of IoT solutions available or still under standardization that will need to be integrated in the 5G framework. UAVs and satellites will be proposed as possible solutions to ease this integration, overcoming the limitations of the terrestrial infrastructure, such as the limited covered areas and the densification of the number of IoT devices per square kilometer
The Role of Satellite in 5G and Beyond
No full textThe first global standard for Satellite Communications (SatCom) was published in April 2022 within 3GPP Release 17. It specifies the features enabling 4G/5G systems to support a satellite component. More than technical specifications, it also enables the integration of the satellite industry in the 3GPP ecosystem, involving organizations at a worldwide level to ensure a global market. Already the decision has been made to define, as part of 3GPP Release 18, some enhancing features to improve the performances and/or to provide new capabilities. Discussions on the contents of Release 19 for the satellite enabling features have started in the service requirement working group of 3GPP. In this framework, it is timely to undertake a study on the technologies for SatCom as part of Beyond 5G (B5G), i.e., 5G-Advanced and 6G. In fact, while Release 17 Non-Terrestrial Network (NTN) provides a solid ground for future satellite networks integrated into the 5G system, a significant innovation breakthrough in technologies, techniques, and architectures is needed to prepare for the next generation. In this chapter, we: (1) detail the 3GPP NTN ecosystem in terms of architectures and challenges; (2) discuss the services and applications; and (3) identify the research challenges to be addressed towards B5G
Energy-aware Routing Algorithm for DTN-Nanosatellite Networks
No full textSatellite constellations are envisioned as meaningful transport networks to forward data throughout the world. Low Earth Orbit (LEO) satellites are the most appealing for this purpose due to their low altitude which allows guaranteeing certain performance, especially in terms of delivery time. Mega-constellation of small LEO satellites (micro- and nano-satellites) are planned to be employed to cover the entire Earth's surface. However, these satellites have several constraints which affect the data forwarding process and have to be taken into account. Energy is one of these constrained resources. Energy storage and recharge are limited by the reduced battery capacity and solar panel surface area, while telecommunication hardware energy consumption is considerable especially in case of high traffic volumes. In this paper, we propose a novel energy-aware routing algorithm based on the Contact Graph Routing (CGR) called E-CGR. E-CGR exploits static and known a priori information about contacts (begin times, end times, and overall contact volumes) to compute complete routing paths from source to destination which are then validated and confirmed from the energy viewpoint
The nucleolus is well-posed
No full textAbstractThe lexicographic order is not representable by a real-valued function, contrary to many other orders or preorders. So, standard tools and results for well-posed minimum problems cannot be used. We prove that under suitable hypotheses it is however possible to guarantee the well-posedness of a lexicographic minimum over a compact or convex set. This result allows us to prove that some game theoretical solution concepts, based on lexicographic order are well-posed: in particular, this is true for the nucleolus
Characterizing properties of approximate solutions for optimization problems
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