34 research outputs found
Nonlinear fibre design for broadband phase sensitive amplification
No full textWe present a soft glass fibre design for high nonlinearity and broadband, low dis-persion and simulate its performance as a phase sensitive amplifier for high bit rate signals at 1 T b/s. We use a degenerate, two pump four wave mixing scheme and show that with a fibre length of less than 1 m we are able to achieve 14 dB discrimination between the amplified and deamplified signal quadratures with 1 W pump power.H. Tilanka Munasinghe, Shahraam Afshar V., David J. Richardson, and Tanya M. Monrohttp://www.iqec-cleopr2011.com/http://www.opticsinfobase.org/abstract.cfm?uri=CLEOPR-2011-C70
Fabrication and properties of lead-germanate glasses for high nonlinearity fibre applications
No full textPaper Tu.3.A.5We report on the fabrication of novel germanate glasses and fibres. We have characterised the glasses in terms of their thermal properties, Raman spectra and refractive indices (both linear and nonlinear) and present them as viable alternatives to tellurite glasses for soft glass optical fiber applications.H. Tilanka Munasinghe, Anja Winterstein-Beckmann, Christian Schiele, Lothar Wondraczek, Danilo Manzani, Shahraam Afshar V., Tanya M. Monro, and Heike Ebendorff-Heidepriemhttp://www.ecoc2013.org
Design and simulation of fuzzy inference based multiple PID controllers for 6-dof unmanned underwatter vehicle
No full textUnmanned underwater vehicles are currently being utilised for scientific, commercial and
military underwater applications. These vehicles require autonomous guidance and control
systems in order to perform underwater tasks. Modelling, simulation and control ofthese
vehicles are still major active areas ofresearch and development.
This thesis explores the design of a control system for a 6-Dof unmanned underwater
vehicle. The thesis consists oftwo phases; the first involves the design ofthree single
decoupled PID controllers for surge, yaw and depth. Then it is shown that it is not possible to
cover the entire range of operations of UUV using only single controller by simulation using
MATLAB SIMULINK. The second phase is concerned with the design ofmultiple PID
controllers covering the entire range of UUV operation, as well as the fuzzy inference based
supervisor design to switch between the different controllers as the operations conditions
vary.
The design ofthe PID controllers are based on MATLAB PID tuning algorithms which is a
robust response time tuning algorithms that allows for faster design process with robust gain
values. It is shown that these new tuning methods as well as graphical tuning interface
overcome the adhoc and time consuming process offinding the PID gains. Further it is
shown that fuzzy gain scheduling using fuzzy inference mechanism is a valid method for
controlling a UUV with nonlinear dynamics.
It can be concluded that new tools such as MATLAB tuning algorithms and Fuzzy toolbox
allows for fast and accurate design of controllers for highly complex systems as well as the
viability offuzzy inference multiple controllers as a method for UUV control with desired
response characteristics. Finally the author recommends an actual vehicle implementation
and testing as future work to be carried out
Ecology and Socialism to Ecosocialism: Roots and Branches
No full textSustainable development discourse attempts to manage trade-offs between the triad of the social (poverty and equity), ecological (natural resources), and economic (growth) (Munasinghe 1993). In contrast, ecosocialism discourse sets up a dialogue between social equity and ecological sustainability. In The Return of Nature, leading Marxist scholar on environmental politics John Bellamy Foster traces the deep intellectual roots that have shaped the ecosocialism project. In elegantly outlining the challenge, the author captures an interesting discursive turn, which is that
A Study of the emerging interest in waterfront developments with the concept of geomentality: with special reference to Colombo
No full textThe Urban waterfront have become increasingly important at different levels and in
diverse aspects. It plays a significant role for the developments of an urban area
which gives many values to the people such as flood management, ecological and
environmental balance and control of urban heat. When consider the world context,
demand for waterfront developments is very high due to the various reasons. This
situation influences to change the natural setting of waterfront characteristics to manmade
characteristics.
Even though demand for waterfront land is increasing, no adequate guidance and
prerequisite demand mechanism are established. Many projects have been launched
spending enormous resources to recover the damage of waterfront environment by
relocating and renovating of existing buildup environment from time to time
Nevertheless, their results were failed to prevent that waterfront environment. The
reason for that lack of proper planning approach and lack of knowledge base for
awareness contributed to the waterfront developments.
Although, economic and environmental forces have been studied in the waterfront
developments, the socio-cultural and psychological forces behind the development
demand for waterfronts are not adequately studied. Therefore, there is a gap in
knowledge in understanding of the influence of the socio-cultural forces.
The broad objective of this study is to investigate the forces that promote the
increasing demand for waterfronts for developments in Sri Lanka. In order to
develop a knowledge base for awareness regarding the emerging demand as an
outcome of the broader socio-economic transformation.
Bolgoda lake waterfront area in Kesbewa Municipal Council limits was selected for
this study. Interview based survey was conducted in 2015, during which key
attributes caused to increase demand for waterfronts were examined. Size of the
randomly selected sample is 50 and data were analyzed using cluster analysis
technique, content analysis method and MS Excel. Study was carried out with
reference to the concept of Geomentality.
Public perceptions regarding to the demand for waterfronts and key attributes
associated with the characteristics of Geomentality were investigated. Accordingly,
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this study was revealed that there is strong combination between demand attributes
and Geomentaity.
In the psychological analysis, the concept of Geomentality explains as a
systematically organized part of environmental perception. According to the analysis,
majority of the demand attributes related to the attitude based responses were mostly
reflected Geomentality characteristics such as Relaxing, Cool environment, Quite and
Calmness and also these attributes are prior to the demand. Although the
Geomentality is the causative factor behind the increasing demand for waterfronts,
some other factors which are not reflected Geomentality characteristics are also
effected for the demand.
Further Geomentality of the respondents was checked by author using some
variables. According to the results of the variables analyzed using by MS Excel, it
was indicated that value of Geomentality based variables is greater than the value of
the non-Geomentality based variables. Further it was revealed that the majority of the
identified Geomentality attributes were reflected by the high income social group.
Finally, it can be concluded that the water is most important planning element which
is comfort of human in physical and psychological. In addition, it brings existing
environment in a number of features in term of aesthetic and functional.
Examining these views, present study can help to obtain a better understanding to
bridge the gaps between the professional and general public as well as provide the
means, by which to develop a knowledge base for awareness
Energy issues in the developing world
No full textIn 1986 and 1987 the lower oil prices called into question many of the fundamental assumptions that were the stock in trade of energy experts during the previous ten years. This document is a collection of papers representing responses to concerns prepared by current and former World Bank staff. Although these papers raise a variety of different concerns, a common theme that runs throughout the paper is the need to continue the pursuit of efficiency goals in the energy sector. The developing world still needs large amounts of capital to meet its ever-expanding energy requirements. These capital requirements will be a significant part of most countries'total investment plan. Given the problems of debt and public revenues, the report concludes that the pursuit of efficiency is just as important under lower fuel prices as it is under rising fuel prices.Power&Energy Conversion,Urban Environment,Environmental Economics&Policies,Energy Demand,Energy and Environment
Linking development, trade, and debt strategies in highly indebted countries
No full textThis paper analyzes the determinants of the choice by debtor countries of a jointly optimal trade and debt strategy after the occurrence of some negative shocks. Choosing between export promotion and import substitution is a matter of determining whether it is more profitable to increase the credit ceiling to borrow more, or to reduce the credit ceiling below inherited debt so there is less to repay. Following the introduction, section 2 of the paper sets up a simple two period trade model. Section 3 analyzes the joint optimal debt and investment strategies, while section 4 discusses extensions. Section 5 reviews the welfare concerns and section 5 provides a conclusion.Economic Theory&Research,Environmental Economics&Policies,Strategic Debt Management,Banks&Banking Reform,Financial Intermediation
Complex tangential flows and compactness of the ∂-Neumann operator
No full textWe provide geometric conditions on the set of boundary points of infinite type of a smooth bounded pseudoconvex domain in Cn implying that the ∂-Neumann operator is compact. These conditions are formulated in terms of certain short time flows in suitable complex tangential directions. It is noteworthy that compactness is not established via the known potential the-oretic sufficient conditions. Our results generalize to Cn the C2 results of the second author
Perceived factors for the effectiveness of online learning for licensed commercial banks in Sri Lanka
No full textThe main focus of this research is to measure the effectiveness of online training in banking industry. The study includes any kind of training program which comes under the computer based training, and it examines the effectiveness of these training
programs with respect to their current involvement in the bank. The study also includes a discussion on how these trainings contribute to employee satisfaction. The
findings are based on responses from questionnaires distributed among banking staff
of selected banks in printed form and by email. The information gathered is subjected to a statistical analysis to derive conclusions.
This research is based on the timely requirement of the industry, factors extracted from previous research work, and expert views. The major factors looked at in this study are, background of the employee related to the bank and its training, type of materials offered in a computer based training, the kind of subjects selected to be offered in computer based training, perception of participated employees, provided infrastructure facilities, and banks contribution to the training programs.
This paper focuses on a selected sample of licensed commercial banks in Sri Lanka to identify the current level of usage of online learning mode and the effectiveness of
online mode of learning for their staff training. It aims to also discuss how this mode can contribute to employee satisfaction in different banks.
As per the findings from this research work, the author claims that the effectiveness of online mode of learning considerably depends on training materials, participants contribution, subject area and ICT infrastructure used in a training program. Also, there is a significant level of employee satisfaction gained by offering online learning
mode of training programs in a bank
Setting the RECORD straight: developing a guideline for the REporting of studies Conducted using Observational Routinely collected Data.
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