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Geoffrey G. Messier

Bio: Geoffrey G. Messier is an academic researcher from University of Calgary. The author has contributed to research in topics: Communication channel & Fading. The author has an hindex of 17, co-authored 85 publications receiving 1538 citations.


Papers
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Journal ArticleDOI
01 Jan 2017
TL;DR: In this paper, the authors propose two multi-trip vehicle routing problems (VRPs) specifically for drone delivery scenarios, one minimizes costs subject to a delivery time limit, while the other minimizes the overall delivery time subject to budget constraint.
Abstract: Unmanned aerial vehicles, or drones, have the potential to significantly reduce the cost and time of making last-mile deliveries and responding to emergencies. Despite this potential, little work has gone into developing vehicle routing problems (VRPs) specifically for drone delivery scenarios. Existing VRPs are insufficient for planning drone deliveries: either multiple trips to the depot are not permitted, leading to solutions with excess drones, or the effect of battery and payload weight on energy consumption is not considered, leading to costly or infeasible routes. We propose two multitrip VRPs for drone delivery that address both issues. One minimizes costs subject to a delivery time limit, while the other minimizes the overall delivery time subject to a budget constraint. We mathematically derive and experimentally validate an energy consumption model for multirotor drones, demonstrating that energy consumption varies approximately linearly with payload and battery weight. We use this approximation to derive mixed integer linear programs for our VRPs. We propose a cost function that considers our energy consumption model and drone reuse, and apply it in a simulated annealing (SA) heuristic for finding suboptimal solutions to practical scenarios. To assist drone delivery practitioners with balancing cost and delivery time, the SA heuristic is used to show that the minimum cost has an inverse exponential relationship with the delivery time limit, and the minimum overall delivery time has an inverse exponential relationship with the budget. Numerical results confirm the importance of reusing drones and optimizing battery size in drone delivery VRPs.

752 citations

Journal ArticleDOI
TL;DR: This paper develops the first optimal receiver design for diffusion-based molecular communication scenarios with and without inter-symbol interference, based on a linear and time invariant signal propagation model and an additive noise model based on Brownian motion molecular statistics.

155 citations

Journal ArticleDOI
TL;DR: This paper uses the non-decision directed maximum likelihood criterion for estimating the channel delay and derives the Cramer-Rao lower bound and evaluates the performance of the proposed synchronization algorithm by investigating its mean square error.
Abstract: Synchronization is an essential feature of any communication system. Due to the very low throughput of molecular communications systems, blind synchronization is preferred in order to reduce communications overhead. In this paper, we present the first blind synchronization algorithm for the diffusion-based molecular communication channel. Considering a diffusion-based physical channel model, we use the non-decision directed maximum likelihood criterion for estimating the channel delay. We then derive the Cramer-Rao lower bound and evaluate the performance of the proposed synchronization algorithm by investigating its mean square error.

110 citations

Patent
09 Apr 1998
TL;DR: In this paper, a method of locating a mobile phone by communicating signal strength measurements of signals received by the mobile phone to a processing unit was proposed, in which the path loss exponent and the position of mobile phone are unknowns.
Abstract: Apparatus for locating a mobile phone in a cellular phone system, in which the cellular phone system comprises plural base stations, each base station being associated with a cell, and in which the mobile phone is programmed to communicate signal strength of received signals to the base stations. Each base station, has a processing unit operably connected to the plural base stations by first communications links, the processing unit having as input the received signal strength measurements, the processing unit being programmed to operate upon the received signal strength measurements to solve a channel model equation in which the position of the mobile phone and the path loss exponent of the cell are unknowns and produce as output position location signals representing the position of the mobile phone in the cell, and a user interface operably connected to the processing unit by a second communication link for communicating signals indicative of the position of the mobile phone in the cell. Various algorithms may be used to solve the channel model equation. A method of locating a mobile phone by A) communicating signal strength measurements of signals received by the mobile phone to a processing unit; B) operating upon the signal strength measurements with the processing unit to solve a channel model equation in which the path loss exponent and the position of the mobile phone are unknowns.

90 citations

Proceedings ArticleDOI
24 Oct 2008
TL;DR: Investigation of the potential for future multiple antenna wireless local area network technologies such as 802.11n to perform indoor network-based positioning using angle of arrival (AOA) estimation shows that with the use of a specialized channel parameter estimation algorithm, quality AOA estimates for positioning might be achieved with low computational complexity.
Abstract: This paper investigates the potential for future multiple antenna wireless local area network technologies such as 802.11n to perform indoor network-based positioning using angle of arrival (AOA) estimation. A multiple-input multiple-output (MIMO) channel measurement system is used to determine the statistical accuracy of the indoor AOA estimation when performed at an 802.11n wireless access point (AP). Two different channel parameter estimation algorithms are used to perform AOA estimation; a simple maximum-likelihood (ML) scheme and the space-alternating generalized expectation-maximization (SAGE) technique. Results indicate that general channel parameter estimation algorithms, such as SAGE, are ill suited to estimate AOA for positioning purposes. However, results show that with the use of a specialized channel parameter estimation algorithm, such as the simple ML algorithm, quality AOA estimates for positioning might be achieved with low computational complexity. A positioning simulation that incorporates the AOA estimates from the simple ML algorithm achieves a positioning accuracy of 1.7 m with the help of an extended Kalman filter.

75 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

01 Jan 2016
TL;DR: The table of integrals series and products is universally compatible with any devices to read and is available in the book collection an online access to it is set as public so you can get it instantly.
Abstract: Thank you very much for downloading table of integrals series and products. Maybe you have knowledge that, people have look hundreds times for their chosen books like this table of integrals series and products, but end up in harmful downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some harmful virus inside their laptop. table of integrals series and products is available in our book collection an online access to it is set as public so you can get it instantly. Our book servers saves in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the table of integrals series and products is universally compatible with any devices to read.

4,085 citations

Patent
06 Dec 2019
TL;DR: In this paper, the authors present methods and systems relating to location-based services such as social networking, providing demographic information, tracking mobile devices, providing business information, providing an adaptable user interface, remotely effecting a change on a portable electronic device, providing a geofence, outputting locationbased information on a mobile device, varying transmissions to and from a mobiledevice, providing locationbased alerts, verifying transactions and tailoring information to the behavior of a user.
Abstract: Provided herein are methods and systems relating to location-based services such as social networking, providing demographic information, tracking mobile devices, providing business information, providing an adaptable user interface, remotely effecting a change on a portable electronic device, providing a geofence, outputting location-based information on a mobile device, varying transmissions to and from a mobile device, providing location-based alerts, verifying transactions and tailoring information to the behavior of a user.

1,653 citations

Journal ArticleDOI
TL;DR: A comprehensive survey of molecular communication (MC) through a communication engineering lens is provided in this paper, which includes different components of the MC transmitter and receiver, as well as the propagation and transport mechanisms.
Abstract: With much advancement in the field of nanotechnology, bioengineering, and synthetic biology over the past decade, microscales and nanoscales devices are becoming a reality. Yet the problem of engineering a reliable communication system between tiny devices is still an open problem. At the same time, despite the prevalence of radio communication, there are still areas where traditional electromagnetic waves find it difficult or expensive to reach. Points of interest in industry, cities, and medical applications often lie in embedded and entrenched areas, accessible only by ventricles at scales too small for conventional radio waves and microwaves, or they are located in such a way that directional high frequency systems are ineffective. Inspired by nature, one solution to these problems is molecular communication (MC), where chemical signals are used to transfer information. Although biologists have studied MC for decades, it has only been researched for roughly 10 year from a communication engineering lens. Significant number of papers have been published to date, but owing to the need for interdisciplinary work, much of the results are preliminary. In this survey, the recent advancements in the field of MC engineering are highlighted. First, the biological, chemical, and physical processes used by an MC system are discussed. This includes different components of the MC transmitter and receiver, as well as the propagation and transport mechanisms. Then, a comprehensive survey of some of the recent works on MC through a communication engineering lens is provided. The survey ends with a technology readiness analysis of MC and future research directions.

762 citations