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Iresha Atthanayake

Bio: Iresha Atthanayake is an academic researcher from University of Warwick. The author has contributed to research in topics: Particle image velocimetry & Jet (fluid). The author has an hindex of 3, co-authored 6 publications receiving 25 citations. Previous affiliations of Iresha Atthanayake include Open University & Open University of Sri Lanka.

Papers
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Proceedings ArticleDOI
05 Sep 2018
TL;DR: Test the information rate in both relatively laminar and turbulent conditions by tracking the information molecules using particle image velocimetry (PIV), and demonstrates experimentally that the variety of obstacles tested do not impact data rate and may in some cases enhance it.
Abstract: A key potential advantage of molecular communications is the ability of molecules to propagate in complex propagation channels. Here, we experimentally test the information rate in both relatively laminar and turbulent conditions by tracking the information molecules using particle image velocimetry (PIV). A number of obstacle types are placed in the channel and we observe that they do not generally lower the information rate, but may actually improve it in some cases. This is explained by the formation of self-sustaining coherent vortex signal structures with a higher signal-to-noise ratio (SNR), which are caused by obstacles. The initial results demonstrate experimentally that the variety of obstacles tested do not impact data rate and may in some cases enhance it.

25 citations

Proceedings ArticleDOI
07 Jun 2020
TL;DR: This experimental paper believes its results can be the basis for long range underwater vertical communication between a deep sea vehicle and a surface buoy, establishing a covert and reliable delay-tolerant data link.
Abstract: Underwater communication is vital for a variety of defence and scientific purposes. Current optical and sonar based carriers can deliver high capacity data rates, but their range and reliability is hampered by heavy propagation loss. A vertical Molecular Communication via Buoyancy (MCvB) channel is experimentally investigated here, where the dominant propagation force is buoyancy. Sequential puffs representing modulated symbols are injected and after the initial loss of momentum, the signal is driven by buoyancy forces which apply to both upwards and downwards channels. Coupled with the complex interaction of turbulent and viscous diffusion, we experimentally demonstrate that sequential symbols exhibit a Gaussian velocity spatial distribution. Our experimental results use Particle Image Velocimetry (PIV) to trace molecular clusters and infer statistical characteristics of their velocity profile. We believe our experimental paper's results can be the basis for long range underwater vertical communication between a deep sea vehicle and a surface buoy, establishing a covert and reliable delay-tolerant data link. The statistical distribution found in this paper is akin to the antenna pattern and the knowledge can be used to improve physical security.

9 citations

Journal ArticleDOI
TL;DR: This method and data paper sets out the macro-scale experimental techniques to acquire fluid dynamic knowledge to inform molecular communication performance and design and two powerful fluid dynamical measurement methodologies that can be applied beneficially in the context of molecular signal tracking and detection techniques.
Abstract: This method and data paper sets out the macro-scale experimental techniques to acquire fluid dynamic knowledge to inform molecular communication performance and design. Fluid dynamic experiments capture latent features that allow the receiver to detect coherent signal structures and infer transmitted parameters for optimal decoding. This paper reviews two powerful fluid dynamical measurement methodologies that can be applied beneficially in the context of molecular signal tracking and detection techniques. The two methods reviewed are Particle Image Velocimetry (PIV) and Planar Laser-Induced Fluorescence (PLIF). Step-by-step procedures for these techniques are outlined as well as comparative evaluation in terms of performance accuracy and practical complexity is offered. The relevant data is available on IEEE DataPort to help in better understanding of these methods.

5 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used particle image velocimetry measurements to investigate the dynamics of turbulent jets in a rotating fluid and found that the frequency of the cycle increases linearly with the background rotation rate.
Abstract: Results of comprehensive particle image velocimetry measurements investigating the dynamics of turbulent jets in a rotating fluid are presented. It is observed that background system rotation induces a time-periodic formation–breakdown cycle of the jets. The flow dynamics associated with this process is studied in detail. It is found that the frequency of the cycle increases linearly with the background rotation rate. The data show that the onset of the breakdown phase and of the reformation phase of the cycle can be characterized in terms of a local Rossby number employing an internal velocity and a length scale of the jet. The critical values for this local Rossby number, for onset of breakdown and reformation, scale linearly with a global Rossby number based on the flow conditions at the source. The analysis of the experimental data suggests centrifugal instability as the potential origin of the formation–breakdown cycle.

4 citations

Journal ArticleDOI
TL;DR: In this article, the performance of a Pelton turbine is analyzed with respect to their blade friction. But, the main focus of the paper is to analyze the impact of blade friction on turbine performance.
Abstract: Water turbines have been used in electricity generation for well over a century. Hydroelectricity now supplies 19% of world electricity. Many hydro power plants are operated with Pelton turbines, which is an impulse turbine. The main reasons for using impulse turbines are that they are very simple and relatively cheap. As the stream flow varies, water flow to the turbine can be easily controlled by changing the number of nozzles or by using adjustable nozzles. Scientific investigation and design of turbines saw rapid advancement during last century. Most of the research that had been done on turbines were focused on improving the performance with particular reference to turbine components such as shaft seals, speed increasers and bearings. There is not much information available on effects of blade friction on the performance of turbine. The main focus in this paper is to analyze the performance of Pelton turbine particularly with respect to their blade friction.

Cited by
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Journal ArticleDOI
20 Jun 2019
TL;DR: This paper provides a tutorial review on mathematical channel modeling for diffusive MC systems and provides the channel models for time-varying MC systems with moving transmitters and receivers, which are relevant for advanced applications such as smart drug delivery with mobile nanomachines.
Abstract: Molecular communication (MC) is a new communication engineering paradigm where molecules are employed as information carriers. MC systems are expected to enable new revolutionary applications, such as sensing of target substances in biotechnology, smart drug delivery in medicine, and monitoring of oil pipelines or chemical reactors in industrial settings. As for any other kind of communication, simple yet sufficiently accurate channel models are needed for the design, analysis, and efficient operation of MC systems. In this paper, we provide a tutorial review on mathematical channel modeling for diffusive MC systems. The considered end-to-end MC channel models incorporate the effects of the release mechanism, the MC environment, and the reception mechanism on the observed information molecules. Thereby, the various existing models for the different components of an MC system are presented under a common framework and the underlying biological, chemical, and physical phenomena are discussed. Deterministic models characterizing the expected number of molecules observed at the receiver and statistical models characterizing the actual number of observed molecules are developed. In addition, we provide the channel models for time-varying MC systems with moving transmitters and receivers, which are relevant for advanced applications such as smart drug delivery with mobile nanomachines. For complex scenarios, where simple MC channel models cannot be obtained from first principles, we investigate the simulation- and experiment-driven channel models. Finally, we provide a detailed discussion of potential challenges, open research problems, and future directions in channel modeling for diffusive MC systems.

251 citations

Book
01 Jan 2012
TL;DR: In this article, the basic principle of Pulse Doppler Principle and velocity uncertainty and resolution was used to limit the position and velocity uncertainties and resolution of ultrasonic doppler frequency.
Abstract: From the Content: Ultrasonic for fluid flow- Fundamentals of ultrasonic wave- Acoustic and ultrasonic wave- Fundamentals of propagation- Ultrasonic Doppler method- Basics- Basic Principle- Pulse Doppler Principle- Velocity Limitation and constraint- Position and velocity uncertainty and resolution- Detection of Doppler frequency- Quadrature-phase Demodulation- Practice Backup-Measurement volume- Selection of basic frequency- Seeding- Conditioning of reflector- Fluid flow & measurement- Basic Fluid Mechanics- Basic equations- Standard velocity field and system performanc

25 citations

Journal ArticleDOI
TL;DR: A general formulation for binary modulation schemes that employ two types of signaling molecules and several modulation schemes as special cases is presented and an algorithm for efficient computation of the CR is developed and validated via particle-based simulation.
Abstract: This paper focuses on molecular communication (MC) systems using two types of signaling molecules which may participate in a reversible bimolecular reaction in the channel. The motivation for studying these MC systems is that they can realize the concept of constructive and destructive signal superposition, which leads to favorable properties, such as inter-symbol interference (ISI) reduction and avoiding environmental contamination due to continuous release of signaling molecules into the channel. This paper first presents a general formulation for binary modulation schemes that employ two types of signaling molecules and proposes several modulation schemes as special cases. Moreover, two types of receivers are considered: 1) a receiver that is able to observe both types of signaling molecules (2TM) and 2) a simpler receiver that can observe only one type of signaling molecules (1TM). For both of these receivers, the maximum likelihood (ML) detector for general binary modulation is derived under the assumption that the detector has perfect knowledge of the ISI-causing sequence. The performance of this genie-aided ML detector yields an upper bound on the performance of any practical detector. In addition, two suboptimal detectors of different complexity are proposed, namely, an ML-based detector that employs an estimate of the ISI-causing sequence and a detector that neglects the effect of ISI. The proposed detectors, except for the detector that neglects ISI for the 2TM receiver, require knowledge of the channel response (CR) of the considered MC system. Moreover, the CR is needed for performance evaluation of all proposed detectors. However, deriving the CR of MC systems with reactive signaling molecules is challenging since the underlying partial differential equations that describe the reaction–diffusion mechanism are coupled and non-linear. Therefore, we develop an algorithm for efficient computation of the CR and validate its accuracy via particle-based simulation. Simulation results obtained using this CR computation algorithm confirm the effectiveness of the proposed modulation and detection schemes. Moreover, these results show that MC systems with reactive signaling have superior performance relative to those with non-reactive signaling due to the reduction of ISI enabled by the chemical reactions.

25 citations

Journal ArticleDOI
TL;DR: An end-to-end theoretical model is proposed for this macro-scale flow-based MC platform with fluidic medium in a semi-cylindrical channel with laminar flow condition and it is validated by experiments as well as simulation results using COMSOL software platform.
Abstract: The macro-scale molecular communication (MC) recently received considerable attention because of its potential applications. Since most of the experimental research in MC focuses on the micro-scale cases, it is necessary to study and implement experiments to investigate the concept’s feasibility as well as to validate the models and parameters. In this paper, a macro-scale flow-based MC platform with fluidic medium is developed, in a semi-cylindrical channel with laminar flow condition. The transmission medium we consider is water in the plexi pipe, a transmitter releases Hydrochloric acid molecules into this pipe and a chemical sensor is used as the receiver. We propose an LTI model for the pH-meter and obtain its parameters based on the experimental results. Next, we design the appropriate encoding-decoding schemes and implement the optimum receiver for the validated model and obtained parameters. To increase the rate, an ISI mitigating method is implemented with adaptive thresholds. In particular, an end-to-end theoretical model is proposed for this system which is confirmed by experiments as well as simulation results using COMSOL software platform. We validate our proposed model and derive related parameters both with the experimental results as well as the simulation results. The performance of the system is analyzed in terms of the bit error probability and the communication rate.

23 citations

Posted Content
TL;DR: In this paper, a general formulation for binary modulation schemes that employ two types of signaling molecules was presented, and two suboptimal detectors of different complexity were proposed, namely an ML-based detector that employs an estimate of the ISI-causing sequence and a detector that neglects the effect of ISI.
Abstract: This paper focuses on molecular communication (MC) systems using two types of signaling molecules which may participate in a reversible bimolecular reaction in the channel. The motivation for studying these MC systems is that they can realize the concept of constructive and destructive signal superposition, which leads to favorable properties such as inter-symbol interference (ISI) reduction and avoiding environmental contamination due to continuous release of signaling molecules into the channel. This work first presents a general formulation for binary modulation schemes that employ two types of signaling molecules and proposes several modulation schemes as special cases. Moreover, two types of receivers are considered: a receiver that is able to observe both types of signaling molecules (2TM), and a simpler receiver that can observe only one type of signaling molecules (1TM). For both of these receivers, the maximum likelihood (ML) detector for general binary modulation is derived under the assumption that the detector has perfect knowledge of the ISI-causing sequence. In addition, two suboptimal detectors of different complexity are proposed, namely an ML-based detector that employs an estimate of the ISI-causing sequence and a detector that neglects the effect of ISI. The proposed detectors, except for the detector that neglects ISI for the 2TM receiver, require knowledge of the channel response (CR) of the considered MC system. Moreover, the CR is needed for performance evaluation of all proposed detectors. However, deriving the CR of MC systems with reactive signaling molecules is challenging since the underlying partial differential equations that describe the reaction-diffusion mechanism are coupled and non-linear. Therefore, we develop an algorithm for efficient computation of the CR and validate its accuracy via particle-based simulation.

22 citations