16 research outputs found
A Survey on Modulation Techniques in Molecular Communication via Diffusion
This survey paper focuses on modulation aspects of molecular communication,
an emerging field focused on building biologically-inspired systems that embed
data within chemical signals. The primary challenges in designing these systems
are how to encode and modulate information onto chemical signals, and how to
design a receiver that can detect and decode the information from the corrupted
chemical signal observed at the destination. In this paper, we focus on
modulation design for molecular communication via diffusion systems. In these
systems, chemical signals are transported using diffusion, possibly assisted by
flow, from the transmitter to the receiver. This tutorial presents recent
advancements in modulation and demodulation schemes for molecular communication
via diffusion. We compare five different modulation types: concentration-based,
type-based, timing-based, spatial, and higher-order modulation techniques. The
end-to-end system designs for each modulation scheme are presented. In
addition, the key metrics used in the literature to evaluate the performance of
these techniques are also presented. Finally, we provide a numerical bit error
rate comparison of prominent modulation techniques using analytical models. We
close the tutorial with a discussion of key open issues and future research
directions for design of molecular communication via diffusion systems.Comment: Preprint of the accepted manuscript for publication in IEEE Surveys
and Tutorial
Macro-Scale Molecular Communications
The use of electromagnetic (EM) waves to transmit information has allowed our society to collaborate and share information on a scale that was unimaginable just a few decades ago. But as with any technology, there are areas where EM-based communications do not function well. For example, underwater and underground communications where EM waves experience high attenuation. This limitation has generated interest in an alternative mode of information transmission, molecular communications. In this thesis, after giving a survey of micro- and macro-scale molecular communications, the two most important aspects of molecular communications are identified: macroscale molecular communications and the experimental analysis of molecular communications. Molecular communication has been dominated so far by interest in the nano-scale, where the application focus is on drug-delivery and DNA communications, etc. Studies in the macro-scale are relatively rare compared to nano- and micro-scale research. This thesis looks closely at macro-scale molecular communication and attempts to improve our understanding of this novel communication paradigm. To achieve this, a mathematical model was developed, based on the advective-diffusion equation (ADE). The model was compared with experimental results, and showed a strong correlation. In addition, a model was developed to simulate molecular communication in both 1D and 3D environments. To generate the modulated chemicals and transmit them in the environment, an inhouse- built odour generator was used, and to detect the chemicals in the environment a mass spectrometer (MS) with a quadrupole mass analyser (QMA) was employed. Mass spectrometers have the ability to distinguish multiple chemicals in the environment concurrently, making them ideal detectors for use in molecular communications. Based on the experimental setup, various aspects of the communication paradigm are investigated in the three main sections. The first section focuses on the fundamental parameters that govern the propagation of molecules in a flow. The second section delves into the communication properties of this new form of information transfer. The final section studies aspects of simultaneous multiple-chemical transmission. Based on this multiple-chemical transmission, modulation methods are developed that exploit this new approach for use in molecular communications
An evaluation of the IPCC IS92 emission scenarios
Scenarios of greenhouse emissions play an important role in the analysis of potential climate change. From a scientific standpoint, they provide a departure point for analyzing the potential occurrence and impacts of climate change; from a policy perspective they provide information about the consequences of action or inaction to reduce gas emissions. This report presents an evaluation of the six IS92 Scenarios. Other published scenarios are also taken into account, but only by way of comparison with the IS92 Scenarios. It is emphasized that this evaluation deals mostly with non-intervention scenarios, that is, scenarios that do not assume any climate policies to reduce greenhouse gas emissions (although they may assume emission controls for other environmental reasons). This applies to five of the six IS92 scenarios that we call non-intervention scenarios. Policy scenarios are only briefly discussed in the evaluation. Because of limited time available for this evaluation, it focuses exclusively on CO2, CH4, N2O, and S emission scenarios from energy and land-use activities. Other sources of greenhouse gases and sinks are not discussed. Despite the somewhat limited focus of the evaluation, it is believed that a wider scope would not have led to significantly different conclusions
Abstracts of manuscripts submitted in 1990 for publication
This volume contans the abstracts of manuscripts submitted for publication during calendar year 1990 by the staff and students
of the Woods Hole Oceanographic Institution. We identify the journal of those manuscripts which are in press or have been
published. The volume is intended to be informative, but not a bibliography.
The abstracts are listed by title in the Table of Contents and are grouped into one of our five deparments, Marine Policy
Center, Coastal Research Center, or the student category. An author index is presented in the back to facilitate locating specific papers
NASA/ASEE Summer Faculty Fellowship Program
This document is a collection of technical reports on research conducted by the participants in the 1993 NASA/ASEE Summer Faculty Fellowship Program at KSC. The basic common objectives of the Program are: to further the professional knowledge of qualified engineering and science faculty members; to stimulate an exchange of ideas between participants and NASA; to enrich and refresh the research and teaching activities of participants' institutions; and to contribute to the research objectives of the NASA centers. 1993 topics include wide band fiber optic communications, a prototype expert/information system for examining environmental risks of KSC activities, alternatives to premise wiring using ATM and microcellular technologies, rack insertion end effector (RIEE) automation, FTIR quantification of industrial hydraulic fluids in perchloroethylene, switch configuration for migration to optical fiber network, and more
Recommended from our members
CONCEPTUAL DESIGN REPORT
Brookhaven National Laboratory has prepared a conceptual design for a world class user facility for scientific research using synchrotron radiation. This facility, called the ''National Synchrotron Light Source II'' (NSLS-II), will provide ultra high brightness and flux and exceptional beam stability. It will also provide advanced insertion devices, optics, detectors, and robotics, and a suite of scientific instruments designed to maximize the scientific output of the facility. Together these will enable the study of material properties and functions with a spatial resolution of {approx}1 nm, an energy resolution of {approx}0.1 meV, and the ultra high sensitivity required to perform spectroscopy on a single atom. The overall objective of the NSLS-II project is to deliver a research facility to advance fundamental science and have the capability to characterize and understand physical properties at the nanoscale, the processes by which nanomaterials can be manipulated and assembled into more complex hierarchical structures, and the new phenomena resulting from such assemblages. It will also be a user facility made available to researchers engaged in a broad spectrum of disciplines from universities, industries, and other laboratories
Fire performance of residential shipping containers designed with a shaft wall system
seven story building made of shipping containers is planned to be built in Barcelona, Spain. This study
mainly aimed to evaluate the fire performance of one of these residential shipping containers whose walls
and ceiling will have a shaft wall system installed.
The default assembly consisted of three fire resistant gypsum boards for vertical panels and a mineral wool
layer within the framing system. This work aimed to assess if system variants (e.g. less gypsum boards, no
mineral wool layer) could still be adequate considering fire resistance purposes.
To determine if steel temperatures would attain a predetermined temperature of 300-350ÂşC (a temperature
value above which mechanical properties of steel start to change significantly) the temperature evolution
within the shaft wall system and the corrugated steel profile of the container was analysed under different
fire conditions.
Diamonds simulator (v. 2020; Buildsoft) was used to perform the heat transfer analysis from the inside
surface of the container (where the fire source was present) and within the shaft wall and the corrugated
profile. To do so gas temperatures near the walls and the ceiling were required, so these temperatures were
obtained from two sources: (1) The standard fire curve ISO834; (2) CFD simulations performed using the
Fire Dynamics Simulator (FDS). Post-flashover fire scenarios were modelled in FDS taking into account
the type of fuel present in residential buildings according to international standards.
The results obtained indicate that temperatures lower than 350ÂşC were attained on the ribbed steel sheet
under all the tested heat exposure conditions. When changing the assembly by removing the mineral wool
layer, fire resistance was found to still be adequate. Therefore, under the tested conditions, the structural
response of the containers would comply with fire protection standards, even in the case where insulation
was reduced.Postprint (published version