Drug policy-making in Sri Lanka 1984-2008: people, politics and power

Policy analysis has not been a part of mainstream Sri Lankan research or academic tradition, and hence there exists a lack of research on policy studies in Sri Lanka. Given also a paucity of research on illicit drug use and contemporary drug policy, this research study generated and analysed a body of evidence about the response to drug misuse and its related policies in Sri Lanka between 1984 and 2008. As the subject of drug policy can be viewed through a variety of perspectives, this thesis adopted a multi-disciplinary approach. It drew on ideas, theories, concepts and research from a variety of social science disciplines such as sociology, political science, international relations, public administration and social policy and included an historical approach to understanding policy development. The study provides an informed narrative describing the rationale for the development of Sri Lanka’s drug policies, their course and outcome and the roles of the various actors, institutions, organisations and interest groups already established, or which came into existence to respond to drug misuse. This shows how, and why, particular policies are shaped and influenced by the actors, institutions and organisations, and by particular discourses. The conceptual foundations for this study were epistemic community theory, stakeholder analysis and policy transfer theory; and the thesis will seek to explain policy in changing contexts. Semi-structured key informant interviews and documentary analysis were the main research methods employed. The analysis revealed that external influences, stakeholder dynamics, consensus in policy approaches, and moral frameworks have combined to sustain a criminal justice model to the management of drug problems and to ward off attempts to introduce a system with a stronger focus on treatment and public health. This study demonstrates that the interests of stakeholders and their relative power significantly influenced the legitimisation of consensual knowledge diffused by epistemic communities which underpinned policy outcomes

On the Feasibility of Fine-Grained TLS Security Configurations in Web Browsers Based on the Requested Domain Name

Most modern web browsers today sacrifice optimal TLS security for backward compatibility. They apply coarse-grained TLS configurations that support (by default) legacy versions of the protocol that have known design weaknesses, and weak ciphersuites that provide fewer security guarantees (e.g. non Forward Secrecy), and silently fall back to them if the server selects to. This introduces various risks including downgrade attacks such as the POODLE attack [15] that exploits the browsers silent fallback mechanism to downgrade the protocol version in order to exploit the legacy version flaws. To achieve a better balance between security and backward compatibility, we propose a mechanism for fine-grained TLS configurations in web browsers based on the sensitivity of the domain name in the HTTPS request using a whitelisting technique. That is, the browser enforces optimal TLS configurations for connections going to sensitive domains while enforcing default configurations for the rest of the connections. We demonstrate the feasibility of our proposal by implementing a proof-of-concept as a Firefox browser extension. We envision this mechanism as a built-in security feature in web browsers, e.g. a button similar to the \quotes{Bookmark} button in Firefox browsers and as a standardised HTTP header, to augment browsers security

Vector Broadcast Channels: Optimality of Threshold Feedback Policies

Beamforming techniques utilizing only partial channel state information (CSI) has gained popularity over other communication strategies requiring perfect CSI thanks to their lower feedback requirements. The amount of feedback in beamforming based communication systems can be further reduced through selective feedback techniques in which only the users with channels good enough are allowed to feed back by means of a decentralized feedback policy. In this paper, we prove that thresholding at the receiver is the rate-wise optimal decentralized feedback policy for feedback limited systems with prescribed feedback constraints. This result is highly adaptable due to its distribution independent nature, provides an analytical justification for the use of threshold feedback policies in practical systems, and reinforces previous work analyzing threshold feedback policies as a selective feedback technique without proving its optimality. It is robust to selfish unilateral deviations. Finally, it reduces the search for rate-wise optimal feedback policies subject to feedback constraints from function spaces to a finite dimensional Euclidean space.Comment: Submitted to IEEE International Symposium on Information Theory, St. Petersburg, Russia, Aug 201

Transmission Rank Selection for Opportunistic Beamforming with Quality of Service Constraints

In this paper, we consider a multi-cell multi-user MISO broadcast channel. The system operates according to the opportunistic beamforming framework in a multi-cell environment with variable number of transmit beams (may alternatively be referred as the transmission rank) at each base station. The maximum number of co-scheduled users in a cell is equal to its transmission rank, thus increasing it will have the effect of increasing the multiplexing gain. However, this will simultaneously increase the amount of interference in the network, which will decrease the rate of communication. This paper focuses on optimally setting the transmission rank at each base station such that a set of Quality of Service (QoS) constraints, that will ensure a guaranteed minimum rate per beam at each base station, is not violated. Expressions representing the achievable region of transmission ranks are obtained considering different network settings. The achievable transmission rank region consists of all achievable transmission rank tuples that satisfy the QoS constraints. Numerical results are also presented to provide further insights on the feasibility problem.Comment: To appear in IEEE ICC 2014, Sydney, Australi

Outage Capacity of Opportunistic Beamforming with Random User Locations

This paper studies the outage capacity of a network consisting of a multitude of heterogenous mobile users, and operating according to the classical opportunistic beamforming framework. The base station is located at the center of the cell, which is modeled as a disk of finite radius. The random user locations are modeled using a homogenous spatial Poisson point process. The received signals are impaired by both fading and location dependent path loss. For this system, we first derive an expression for the beam outage probability. This expression holds for all path loss models that satisfy some mild conditions. Then, we focus on two specific path loss models (i.e., an unbounded model and a more realistic bounded one) to illustrate the applications of our results. In the large system limit where the cell radius tends to infinity, the beam outage capacity and its scaling behavior are derived for the selected specific path loss models. It is shown that the beam outage capacity scales logarithmically for the unbounded model. On the other hand, this scaling behavior becomes double logarithmic for the bounded model. Intuitive explanations are provided as to why we observe different scaling behavior for different path loss models. Numerical evaluations are performed to give further insights, and to illustrate the applicability of the outage capacity results even to a cell having a small finite radius.Comment: To appear in Globecom 2013, Atlanta, US

The Distribution of ESBL-Producing Enterobacteriaceae: Leicestershire UK Compared to Worldwide

open access articl

Vector Broadcast Channels: Optimal Threshold Selection Problem

Threshold feedback policies are well known and provably rate-wise optimal selective feedback techniques for communication systems requiring partial channel state information (CSI). However, optimal selection of thresholds at mobile users to maximize information theoretic data rates subject to feedback constraints is an open problem. In this paper, we focus on the optimal threshold selection problem, and provide a solution for this problem for finite feedback systems. Rather surprisingly, we show that using the same threshold values at all mobile users is not always a rate-wise optimal feedback strategy, even for a system with identical users experiencing statistically the same channel conditions. By utilizing the theory of majorization, we identify an underlying Schur-concave structure in the rate function and obtain sufficient conditions for a homogenous threshold feedback policy to be optimal. Our results hold for most fading channel models, and we illustrate an application of our results to familiar Rayleigh fading channels.Comment: Submitted to IEEE International Symposium on Information Theory, St. Petersburg, Russia, Aug 201

Preliminary Analysis of the Anti-biofilm Efficacy of Manuka Honey on Extended Spectrum Β-lactamase Producing Escherichia Coli Tem-3 and Klebsiella Pneumoniae Shv18, Associated with Urinary Tract Infections

open access articleUrinary Tract Infections (UTIs) are one of the most common infections in the UK and many other parts of the world. The prevalence of the Extended Spectrum β-Lactamases (ESBLs) producing UTIs, combined with their ability to form a bio film, has significantly risen and is limiting therapeutic options. This study investigated the anti-bio film activity of Manuka honey on two ESBL producing pathogens, Escherichia coli TEM-3 and Klebsiella pneumonia SHV18, commonly found in UTIs. The ESBL production was confirmed by the double disk synergy method used to confirm the ESBL production. The antibacterial activity of Manuka honey was determined using the agar well diffusion method. The Minimum Inhibitory Concentration (MIC) was established using serially diluted honey ranging from 50% to 1.56%. The effect of Manuka honey on the pathogen bio films was analysed using the Tissue Culture Plate method, with an established MIC and under 24h incubation with the honey. The results indicated that K. pneumonia SHV18 is a stronger bio film producer than E. coli TEM 3. 50% (w/v) MIC Manuka honey appears to fully prevent the plank tonic growth of both strains. A significant reduction of 81% of the E. coli TEM3 (p < 0.001) and 52% of the K. pneumonia SHV18 (p = 0.001) bio film biomass was observed. The E. coli bio films were found to be more sensitive to the 50% (w/v) honey dilution than those produced by K. pneumonia. The study indicated the anti-bio film potency of Manuka honey and its potential to become an alternative treatment for the ESBL producing pathogens associated with UTIs

Flood prone risk and amenity values: a spatial hedonic analysis

This study examines the impact of flood hazard zone location on residential property values. The study utilises data from over 2,000 private residential property sales occurred during 2006 in North Shore City, New Zealand. A spatial autoregressive hedonic model is developed to provide efficient estimates of the marginal effect of flood prone risks on property values. Our results suggest that a property located within a flood hazard zone sells for 4.3% less than an equivalent property located outside the flood hazard zone. Given the median house price, estimated discount associated with flood risks is approximately NZ$22,000.Flood hazard, Spatial hedonic, Amenity value, Land Economics/Use, Q15, Q51,