238,134 research outputs found
Context-aware Peer-to-Peer and Cooperative Positioning
Peer-to-peer and cooperative positioning represent one of the major evolutions for mass-market positioning, bringing together capabilities of Satellite Navigation and Communication Systems. It is well known that smartphones already provide user position leveraging both GNSS and information collected through the communication network (e.g., Assisted-GNSS). However, exploiting the exchange of information among close users can attain further benefits. In this paper, we deal with such an approach and show that sharing information on the environmental conditions that characterize the reception of satellite signals can be effectively exploited to improve the accuracy and availability of user positioning. This approach extends the positioning service to indoor environments and, in general, to any scenario where full visibility of the satellite constellation cannot be grante
Successful Approaches for the Use of Unmanned Aerial Systems by Surface Transportation Agencies
The past decade has seen ever-increasing attention and resources dedicated to the application and operation of unmanned aircraft systems (UASs). Beginning with issuance of special airworthiness certificates in the experimental category for unmanned aircraft in 2007, up to the Federal Aviation Administration’s (FAA’s) Modernization and Reform Act of 2012 and creation of Title 14 Code of Federal Regulations (CFR) §107 and §101, the complexity and breadth of applications for UAS technology have flourished.
Recognizing the interest and potential benefits to the surface transportation community the National Cooperative Highway Research Program (NCHRP) commissioned Scan 17-01 to accelerate beneficial innovation by facilitating information sharing and technology exchange among the states and other transportation agencies. Results from a desk scan, amplifying questions, and a peer exchange workshop produced conclusions and recommendations in seven topic areas for transportation agencies to consider when getting started using a UAS
Decentralized Control of Cooperative Systems: Categorization and Complexity Analysis
Decentralized control of cooperative systems captures the operation of a
group of decision makers that share a single global objective. The difficulty
in solving optimally such problems arises when the agents lack full
observability of the global state of the system when they operate. The general
problem has been shown to be NEXP-complete. In this paper, we identify classes
of decentralized control problems whose complexity ranges between NEXP and P.
In particular, we study problems characterized by independent transitions,
independent observations, and goal-oriented objective functions. Two algorithms
are shown to solve optimally useful classes of goal-oriented decentralized
processes in polynomial time. This paper also studies information sharing among
the decision-makers, which can improve their performance. We distinguish
between three ways in which agents can exchange information: indirect
communication, direct communication and sharing state features that are not
controlled by the agents. Our analysis shows that for every class of problems
we consider, introducing direct or indirect communication does not change the
worst-case complexity. The results provide a better understanding of the
complexity of decentralized control problems that arise in practice and
facilitate the development of planning algorithms for these problems
Signalling Design in Sensor-Assisted mmWave Communications for Cooperative Driving
Millimeter-Wave (mmWave) Vehicle-To-Vehicle (V2V) communications are a key enabler for connected and automated vehicles, as they support the low-latency exchange of control signals and high-resolution imaging data for maneuvering coordination.
The employment of mmWave V2V communications calls for Beam Alignment and Tracking (BAT) procedures to ensure that the antenna beams are properly steered during motion. The conventional beam sweeping approach is known to be unsuited for the high vehicular mobility and its large overhead reduces transmission efficiency. A promising solution to reduce BAT signalling foresees the integration of V2V communication systems with on-board vehicle sensors. We focus on a cooperative sensor-assisted architecture for mmWave V2V communications in line of sight, where vehicles exchange the estimate of antenna position and its uncertainty to compute the optimal beam direction and dimension.
We analyze and compare different signalling strategies for sharing the information on antenna estimate, evaluating the tradeoff between signalling overhead and performance loss for different position and uncertainty encoding strategies. Main attention is given to differential quantization on both the antenna position and uncertainty. Analyses over realistic urban mobility trajectories suggest that differential approaches introduce a negligible performance loss while significantly reducing the BAT signalling communication overhead
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Small and Medium sized Enterprises’ Collaborative Buyer-Supplier Relationships: Boundary Spanning Individual Perspectives
Boundary-spanning individuals (BSIs) play a critical role in supply chain management, especially in small and medium sized enterprises (SMEs) where interactions with buyers and suppliers can depend heavily on just a few individuals. This study, utilizing data from Korean manufacturing-sector SMEs, explores whether cooperative social value orientations of SMEs’ BSIs influence the effects of collaborative buyer-supplier initiatives. The results suggested that the performance implication of decision-sharing initiative increases when BSIs have a high level of cooperative social value orientation. However, it also negatively moderates the relationship between risk/benefit sharing (involving financial losses or gains) and performance suggesting possible negative side-effects. However, we found that such orientation also negatively moderates the relationship between risk/benefit sharing (involving direct financial losses or gains) and relationship performance suggesting possible negative side-effects
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