Browsing by Author "Premaratne, U"

Now showing 1 - 10 of 10

item: Article-Abstract
Characterization of Event Based Sampling Encoders for Industrial Internet of Things using Input-Output Mutual Information
(2020-09-28) Premaratne, U; Warnakulasooriya, S; Nandana, R
The emergence of Industry 4.0 has resulted in a rapid increase in the demand for bandwidth due to the proliferation of Industrial Internet of Things (IIoT). Increased utilization of the network also gives rise to undesirable consequences such as high latency and increased likelihood of data loss through packet drops. Encoding inputs using event based sampling is a potential solution for decreasing network traffic generated when continuous input variables are sampled. The problem addressed by this paper is the fact that currently there is no effective method for comparing different encoders. The resulting contribution is the use of mutual information to compare the input and encoded output in terms of accuracy for the currently most efficient encoders that use either Memory Based Event Triggering (MBET) or Deadband Error Modulation (DEM). This allows a practitioner to select a suitable encoder for a given input specification.
item: Conference-Abstract
A Critical investigation of the possible compliance standards of academic and research ethics under the right to Information Act of Sri Lanka
Premaratne, U
Research ethics, Right to Information Act, Freedom of information
item: Article-Full-text
Event triggered adaptive differential modulation: A new method for traffic reduction in networked control systems
(IEEE, 2013) Premaratne, U; Halgamuge, SK; Mareels, IMY
Congestion in a networked control system (NCS) has many undesirable effects that can make a control system unstable if severe enough. These include delays and packet drops. Therefore, reducing network traffic, including traffic generated by the NCS itself is a necessity. In event based control (EBC) a control signal is generated when a specific event is triggered such as the control error exceeding a predetermined threshold. When the rate of change of a variable is bounded, event triggering reduces the effective frequency in which control signals have to be generated when compared to a system with periodic sampling. This paper proposes a new method of event triggering called event triggered adaptive differential modulation (ETADM) that combines the bandwidth reduction strategies of event triggering and human speech coding techniques. The proposed method can be applied to nonlinear systems with a stabilizing feedback. In addition, it can be shown to be robust to packet drops. Stability for this method can be analyzed in terms of input to state stability (ISS) for a given bound of the signal reconstruction error.
item: Article-Full-text
Extremum seeking control with sporadic packet transmission for networked control systems
(IEE, 2020) Premaratne, U; Halgamuge, S; Tan, Y; Mareels, IMY
Extremum seeking control (ESC) is a data-driven optimization technique that can steer a dynamic plant toward an extremum of an unknown but measurable input to steady-state output. In the context of networked control systems, a new implementation method for ESC inspired by the well-known Luus-Jaakola algorithm is proposed. The main motivation is to minimize the communication burden associated with the search phase of ESC. In the proposed method, the controller only requires a notification of a change registered at the sensor, rather than the full information available at the sensor. This event-based approach leads to sporadic packet transmission. In addition, the proposed method is able to directly account for constraints while seeking the desired extremum. The constraints may be of the inequality or equality type. The algorithm's behavior is illustrated on a networked water pump control system.
item: Conference-Full-text
Limit cycle like asymptotic dynamics in feedback loops with memory based event triggering
(IEEE, 2016-04) Premaratne, U; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
Memory Based Event Triggering (MBET) is a pragmatic approach to reduce the effective sampling rate of a control system. In MBET, periodically sampled state variables and control inputs are encoded such that data transmission takes place only when they change by a value that exceeds a predetermined threshold. This results in a significant reduction of network traffic in Networked Control Systems (NCS). Should MBET encoding result in an asymptotic cyclic behavior (limit cycle like behavior), it would result in a lower bound in the required bandwidth. In this paper, the necessary conditions for the formation of such a cycle are investigated. It is demonstrated analytically as well as through empirical simulations that the main requirement for the occurrence of asymptotic dynamic cycles is a diffeomorphism between a scalar control input and a unique equilibrium point to which the system will converge to for a constant control input.
item: Conference-Full-text
Potential of ambient radio frequency energy harvesting from an industrial dielectric heater
(Institute of Electrical and Electronics Engineers, Inc., 2018-09) Dasanayake, DMHT; Anuruddha, G; Premaratne, U; Samarasinghe, R; Abeygunawardana, S
Dielectric heaters are mainly used in industry for various applications. Due to generation of near field energy from stray electromagnetic fields, these machines were selected for analysis as a source for RF energy harvesting. In this research, the energy harvester was designed using a ferrite core loop antenna, rectifying and smoothing circuit and an ultra-low power management system in order to provide energy to a temperature and humidity sensor node. This application was tested within the footwear manufacturing industry due to availability of dielectric heaters (RF Welding Machine) and temperature and humidity are continuously measured during the production process.
item: Conference-Abstract
Robust texture based biomass estimation of small fronded floating aquatic plants using j-values
Wimalaratne, S; Premaratne, U
This paper proposes a new method of estimation of the wet biomass of three floating aquatic plants, Spirodela polyrhiza, Lemna minor and Azolla pinnata. The method uses a homogeneity measure known as the J-value to detect the texture of the fronds of the plants from the uniform water surface. The proposed method is called J-value thresholding (JVT) and is highly accurate compared to the alternative green layer extraction (GLE). The average accuracy under normal illumination for the proposed method is 91.59% for Spirodela polyrhiza, 80.11% for Lemna minor and 77.4% for Azolla pinnata. Furthermore, it is robust to different illumination levels with the Pearson correlation coefficient of the estimates of different illumination levels being above 95%. When used to obtain the growth rate of each plant specie through linear regression, the result from the proposed method is highly consistent with the ground truth of the image.
item: Article-Full-text
A sum of bernoulli sources approximation for packet switched network traffic in backbone links
(IEE, 2020) Premaratne, U; Premarathne, US
In this letter an intuitive measurement based approximation for packet switched network traffic in backbone links is presented. It consists of a sum of independent non-identical Bernoulli sources. The resulting sum has a Poisson binomial distribution which can be approximated to a skewed Gaussian distribution at the asymptote. It can be further approximated to a binomial distribution for predicting congestion by estimating the number of users of the network. The results are verified using samples of traffic data from 42 academic and research institutions.
item: Article-Full-text
Traffic Reduction in Packet Switched Networked Control Systems Using Deadband Error Modulation
(IEEE, 2017) Premaratne, U; Halgamuge, SK; Mareels, IMY
This paper introduces a novel traffic reduction method for Networked Control Systems (NCS) called Deadband Error Modulation (DEM). The deadband modifies the periodic dynamics of Delta Modulation (DM) based techniques such as our previously proposed Event Triggered Adaptive Differential Modulation (ETADM). Like ETADM it can be used for encoding individual scalar elements of a vector (i.e., the state vector or control input). It is also robust to bounded packet drops.
item: Conference-Full-text
Unified protection for the informed decision in business transactions by legal test
Premaratne, U
Consumers and companies alike require to make countless informed decisions in the context of commercial activities. Going beyond the trivial purchase of a substandard good or service, the informed decision is a choice made after a comprehensive evaluation of the reasonably predicted possible outcomes of each potential option. A typical example would be a consumer without expert knowledge in energy, investing in a solar power system. Under such circumstances the consumer has to be aware if there will be a benefit compared to the no action alternative which requires both information provided by the manufacturer and possible reliance on expert opinion. Venture capitalists and hedging fund managers face similar circumstances where they need to invest based upon informed decisions of the subject as well as the risks. This paper investigates the available legal remedies in both local and foreign jurisdictions for consumers and companies when deprived of an informed decision due to restriction of information, deception or perfidy. Based on this, a judicial test is formulated to allow a generalized protection of the informed decision in business transactions.