1,212 research outputs found
Monetary Policy Announcements and Market Interest Rates in Pakistan: An Event Study Approach.
The objective of this paper is to analyse the impact of
monetary policy (MP) announcements on market interest rates at different
nine maturities (1/Week, 2/Week, 1/Month, 3/Months, 6/Months, 9/Months,
1/Year, 2/Years and 3/Years) in Pakistan. The Event window of 11 days
and an estimation window of 250 days have been used for analysis. The
study did not find significant evidence of ARCH effect in market
interest rates at (1/Year, 2/Years and 3/Years) maturities. However,
there is evidence of significant abnormal returns which shows a positive
impact of monetary policy announcements on market interest rates at
different nine maturities. Keywords: Monetary Policy, Market Interest
Rates, Normal Rates, Abnormal Rates, GARCH, ARIM
Momentum Effect: Empirical Evidence from Karachi Stock Exchange
Capital market efficiency and the prediction of future stock
prices are the most thought-provoking and ferociously debated areas in
finance. The followers of traditional financial theory strongly believe
that the markets are efficient in pricing the financial instruments.
This view became popular after Fama’s work on the Efficient Market
Hypothesis. But before 1990s, wide-ranging financial literature
documented that stock prices, to some extent, are predictable. Many
psychologists, economist and the journalists are of the view that
general tendency of individuals is to overreact to the information. De
Bondt and Thaler (1985) studies this view of experimental psychology
that whether such behaviour matters at the market level or not. They
found out that stock prices will overreact to information, and suggested
that contrarian strategies buy the past losers and sell the past
winners, earn abnormal returns. They extended the holding period from 3
to 5 years and provide the evidence of long term returns reversal.
Jegadeesh (1990) and Lehmann (1990) supported the evidence of return
reversal in short term, i.e. from one week to one month. They suggested
that the contrarian strategies having holding period of one week to one
month earned the significant abnormal return. Lo and Mac Kinalay (1990)
objected on the ground that a major portion of this abnormal return,
reported by Jegadeesh (1990) and Lehmann (1990), is due to the delayed
reaction of stock prices to common factors rather than to overreaction.
Some other researchers pointed out some other reasons of this abnormal
stock returns i.e. short-term pressure on stock prices and absence of
liquidity in the market rather than overreaction
Housing the urban poor in Bangladesh : a study of housing conditions, policies and organisations
The rapid urbanisation process in developing countries has heightened the crisis of employment, shelter provision and urban services. The increased number of urban population and lack of institutional capacity is causing urban poverty, which has two-way cause-effect relationship with inadequate housing and service provision. In Bangladesh almost 30% of the urban population is living in slums and squatters. To address the housing issues of the urban poor, different programmes and policies have been designed and implemented internationally based on different macro-economic development approaches. The main development approaches are Modernisation, Keynesian, Basic Needs, Neo-liberal and Collaborative, which have been translated in different housing approaches like Conventional Housing, Public and Self-help Housing, Aided Self-help Housing, Enabling Mechanism and Community-led Housing. Thus the development approaches reframes the housing policies of a country and restructures the housing provision through different organisational arrangements to change the housing conditions of the urban poor. This study therefore examine the impact of development approaches for housing the urban poor in Bangladesh by analysing the housing conditions, policies and organisations drawing on the international theories, policies and practices. In analysing the recent context, the emphasis has been given on the impact of neo-liberalism as it is the current pre-dominant development approach in Bangladesh.
By reviewing theories, policies and practices, this research first addresses the question whether there is any interrelation between housing and urban poverty, which can be capitalised for poverty alleviation. This research also explores – how ideas on pro-poor housing have evolved over time and whether these have produced varied results under different development approaches. It also investigates the roles of different actors under different organisational arrangements of housing provision influenced by the recent development approaches. The research then applies the concepts drawn from the international perspective to build an understanding of the Bangladesh context. Thus the research is mostly qualitative in nature and the international perspective is based on a review of the literature. To understand the Bangladesh context, in the macro level policy analysis, grey materials (unpublished policy documents) and key informant interview were the main methods of data collection. To understand the housing conditions of the urban poor, at the macro level secondary information has been used, and in the micro level - information has been collected from two case study settlements. For the
descriptive statistics - census data of case study settlements has been collected in partnership with the Urban Partnership for Poverty Reduction Programme team. Sixty household interviews and four focus group discussions were performed to acquire qualitative information on the housing process of the urban poor including the role of different actors for service provision in those settlements.
The research found that theoretically there is an interrelation between housing and urban poverty, as housing acts as an asset for ensuring livelihood opportunities for the urban poor. The empirical evidence of Bangladesh also shows that there is a symbiotic relationship between housing and livelihood opportunity of the urban poor. The threat of eviction and lack of service provision affect this livelihood opportunity. Internationally to address the housing issues of the urban poor several attempts have been made based on different development approaches. In Bangladesh these practices were introduced under the pressure of external agencies rather than any endogenous attempt and failed to cater for the urban poor. Though different approaches exist internationally, in Bangladesh, neo-liberalism is the pre-dominant approach for articulating public policies. Most of the public policies thus refer to the market enabling approach for housing the urban poor. Internationally, the organisational arrangement of decentralisation has been seen as a pro-poor arrangement under the market enabling approach. In Bangladesh this arrangement failed to deliver housing and services for the urban poor. The co-existence of the 'participatory enabling approach‘ and 'market enabling approach‘ in Bangladesh is another major finding of this research. The 'participatory enabling approach‘ has been exercised through a few externally aided programmes and projects and the existing organisational arrangement is not conducive to this approach, which this research refers to as a policy failure. Moreover, this research identifies that 'market enabling approach‘ under the neo-liberal development approach failed to improve the housing conditions of the urban poor, failed to articulate pro-poor policy frameworks which affected the organisational arrangements and modes of housing provision for the urban poor. However, understanding the capability of informal networked actions of the urban poor, this research also advocates a 'participatory enabling approach‘ and a pro-poor housing policy in Bangladesh
New Topologies and Advanced Control of Power Electronic Converters for Renewable Energy based Microgrids
Solar energy-based microgrids are increasingly promising due to their many features, such as being environmentally friendly and having low operating costs. Power electronic converters, filters, and transformers are the key components to integrate the solar photovoltaic (PV) systems with the microgrids. The power electronic converters play an important role to reduce the size of the filter circuit and eliminate the use of the bulky and heavy traditional power frequency step-up transformer. These power converters also play a vital role to integrate the energy storage systems such as batteries and the superconducting magnetic energy storage (SMES) unit in a solar PV power-based microgrid. However, the performance of these power converters depends upon the switching technique and the power converter configuration. The switching techniques can improve the power quality, i.e. lower total harmonic distortion at the converter output waveform, reduce the converter power loss, and can effectively utilize the dc bus voltage, which helps to improve the power conversion efficiency of the power electronic converter. The power converter configuration can reduce the size of the power converter and make the power conversion system more efficient. In addition to the advanced switching technique, a supervisory control can also be integrated with these power converters to ensure the optimal power flow within the microgrid.
First, this thesis reviews different existing power converter topologies with their switching techniques and control strategies for the grid integration of solar PV systems. To eliminate the use of the bulky and heavy line frequency step-up transformer to integrate solar PV systems to medium voltage grids, the high frequency magnetic linkbased medium voltage power converter topologies are discussed and compared based on their performance parameters. Moreover, switching and conduction losses are calculated to compare the performance of the switching techniques for the magnetic-linked power converter topologies.
In this thesis, a new pulse width modulation technique has been proposed to integrate the SMES system with the solar PV system-based microgrid. The pulse width modulation technique is designed to provide reactive power into the network in an effective way. The modulation technique ensures lower total harmonic distortion (THD), lower switching loss, and better utilization of dc-bus voltage. The simulation and experimental results show the effectiveness of the proposed pulse width modulation technique.
In this thesis, an improved version of the previously proposed switching technique has been designed for a transformer-less PV inverter. The improved switching technique can ensure effective active power flow into the network. A new switching scheme has been proposed for reactive power control to avoid unnecessary switching faced by the traditional switching technique in a transformer-less PV inverter. The proposed switching technique is based on the peak point value of the grid current and ensures lower switching loss compared to other switching techniques.
In this thesis, a new magnetic-linked multilevel inverter has been designed to overcome the issues faced by the two-level inverters and traditional multilevel inverters. The proposed multilevel inverter utilizes the same number of electronic switches but fewer capacitors compared to the traditional multilevel inverters. The proposed multilevel inverter solves the capacitor voltage balancing and utilizes 25% more of the dc bus voltage compared to the traditional multilevel inverter, which reduces the power rating of the dc power source components and also extends the input voltage operating range of the inverter.
An improved version magnetic-linked multilevel inverter is proposed in this thesis with a model predictive control technique. This multilevel inverter reduces both the number of switches and capacitors compared to the traditional multilevel inverter. This multilevel inverter also solves the capacitor voltage balancing issue and utilizes 50% more of the dc bus voltage compared to the traditional multilevel inverter.
Finally, an energy management system has been designed for the developed power converter and control to achieve energy resiliency and minimum operating cost of the microgrid. The model predictive control-based energy management system utilizes the predicted load data, PV insolation data from web service, electricity price data, and battery state of charge data to select the battery charging and discharging pattern over the day. This model predictive control-based supervisory control with the advanced power electronic converter and control makes the PV energy-based microgrid more efficient and reliable
Channel Impulse Response-based Distributed Physical Layer Authentication
In this preliminary work, we study the problem of {\it distributed}
authentication in wireless networks. Specifically, we consider a system where
multiple Bob (sensor) nodes listen to a channel and report their {\it
correlated} measurements to a Fusion Center (FC) which makes the ultimate
authentication decision. For the feature-based authentication at the FC,
channel impulse response has been utilized as the device fingerprint.
Additionally, the {\it correlated} measurements by the Bob nodes allow us to
invoke Compressed sensing to significantly reduce the reporting overhead to the
FC. Numerical results show that: i) the detection performance of the FC is
superior to that of a single Bob-node, ii) compressed sensing leads to at least
overhead reduction on the reporting channel at the expense of a small
( dB) SNR margin to achieve the same detection performance.Comment: 6 pages, 5 figures, accepted for presentation at IEEE VTC 2017 Sprin
Blockchain-based access control management for Decentralized Online Social Networks
Online Social Networks (OSNs) represent today a big communication channel where users spend a lot of time to share personal data. Unfortunately, the big popularity of OSNs can be compared with their big privacy issues. Indeed, several recent scandals have demonstrated their vulnerability. Decentralized Online Social Networks (DOSNs) have been proposed as an alternative solution to the current centralized OSNs. DOSNs do not have a service provider that acts as central authority and users have more control over their information. Several DOSNs have been proposed during the last years. However, the decentralization of the social services requires efficient distributed solutions for protecting the privacy of users. During the last years the blockchain technology has been applied to Social Networks in order to overcome the privacy issues and to offer a real solution to the privacy issues in a decentralized system. However, in these platforms the blockchain is usually used as a storage, and content is public. In this paper, we propose a manageable and auditable access control framework for DOSNs using blockchain technology for the definition of privacy policies. The resource owner uses the public key of the subject to define auditable access control policies using Access Control List (ACL), while the private key associated with the subject's Ethereum account is used to decrypt the private data once access permission is validated on the blockchain. We provide an evaluation of our approach by exploiting the Rinkeby Ethereum testnet to deploy the smart contracts. Experimental results clearly show that our proposed ACL-based access control outperforms the Attribute-based access control (ABAC) in terms of gas cost. Indeed, a simple ABAC evaluation function requires 280,000 gas, instead our scheme requires 61,648 gas to evaluate ACL rules
Care of terminally-ill patients: an opinion survey among critical care healthcare providers in the Middle East
Background: Modern medicine has allowed physicians to support the dying terminally-ill patient with artificial means. However, a common dilemma faced by physicians in general, and intensivist in particular is when to limit or withdraw aggressive intervention.Objective: To study the effect of training background and seniority on Do-not to resuscitate (DNR) decisions in the Middle East.Methods: Anonymous questionnaire sent to members of the Pan Arab Society of Critical Care.Results: The response rate was 46.2%. Most of the responders were Muslim (86%) and consultants (70.9%). Majority of the responders were trained in western countries. Religion played a major role in 59.3% for making the DNR decision. DNR was considered equivalent to comfort care by 39.5%. In a futile case scenario, Do Not Escalate Therapy was preferred (54.7%). The likelihood of a patient, once labeled DNR, being clinically neglected was a concern among 46.5%. Admission of DNR patients to the ICU was acceptable for 47.7%. Almost one-half of the responders (46.5%) wanted physicians to have the ultimate authority in the DNR decision. Training background was a significant factor affecting the interpretation of the term no code DNR (P< 0.008).Conclusion: Training background and level of seniority in critical care provider does not impact opinion on most of end of life issues related to care of terminally-ill patients. However, DNR is considered equivalent to comfort care among majority of Middle Eastern trained physicians.Keywords: Do-not resuscitate, Islam, care of terminally-ill, opinion, trainingAfrican Health Sciences 2013; 13(4): 893 - 89
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