Heriot-Watt University
ROS: The Research Output Service. Heriot-Watt University EdinburghNot a member yet
4689 research outputs found
Sort by
Random graphs and stochastic networks : limits and approximations
Get PDFThis thesis is divided into four distinct chapters.
In Chapter 1 we give a brief history of the study of random graphs and stochastic networks, as well as a description of the results of the remaining chapters and an introduction
to some common notation we will use.
Chapter 2 is focused on finding how the expected numbers of certain structures grow
asymptotically in a scale-free Chung-Lu random graph. In such a graph nodes are independently assigned weights according to a distribution with tail probability h
1−α
l(h),
where α > 2 and l(h) is a slowly-varying function, and each pair of nodes is connected
by an edge with probability proportional to the product of their two weights.
After introducing the model in Section 2.1 this chapter is further subdivided into three
parts: in Section 2.2 we study the growth of the number of cliques (complete sub-graphs)
in the graph, in Section 2.3 we study how these asymptotics change when conditioning
on the presence of a "mutual friend" (a node of known weight connected to every other
node in the structure) and in Section 2.4 we present a general optimisation method for
finding these growth rates for any finite sub-graph.
Chapter 3 addresses results regarding the number of individuals in the n
th generation
of a branching random walk which exist to the right of a given increasing threshold. In
particular we find sharp asymptotics for the expectation and variance of this number when
the offspring distribution of the branching random walk is constant and the displacement
distribution belongs to a certain wide class of heavy-tailed distributions.
Finally, in Chapter 4 we explore the maximum throughput for the ALOHA system,
a type of random access protocol, when modified to include a process of "retries" for
transmissions and a decentralised algorithm to estimate the number of terminals wishing
to transmit
Time-lapse seismic monitoring of dynamic rock property changes due to an explosive event at depth
Get PDFAfter the second world war and the cold war, nuclear weapon disarmament and the
prohibition of nuclear tests has become a significant global security issue. The United
Nations established the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) in 1996 to develop verification regimes to
monitor nuclear weapon testing. Characterising seismic events as underground nuclear explosions is a challenging task. The On-Site Inspection (OSI), carried out by a
trained Inspection Team at the suspected nuclear test location, is the most invasive
verification method under the Comprehensive Test-Ban Treaty (CTBT). The team
verifies the suspicious event using a suite of scientific techniques such as visual observation, radio-nuclide (RN) measurement techniques, geophysical methods including
seismic monitoring, etc., to link post-explosion phenomena to potential sources. The
main challenges in seismic monitoring involve accurately locating the test location
and separating underground variations in seismic properties due to the explosion
from naturally occurring variations. Moreover, the OSI verification operations occur several days/months after the explosion, which would lead to possible variation
in the detectability of nuclear-explosion related anomalies due to their decay over
time. This study explores the potential of implementing seismic time-lapse monitoring techniques to locate underground explosion zone by detecting the explosion
related seismic property variation. This project’s scope is drawn within the framework of the CTBTO treaty to develop a monitoring technique that can be acquired,
processed, and interpreted within the 130 days post-explosion On-Site Inspection
period.
An underground nuclear explosion (UNE) produces characteristic static and dynamic signatures due to the sudden release of intense pressure and thermal energy.
Geological deformations, such as a cavity, rubble chimney, rock compaction, and
fracturing, collectively known as the ‘cavity system’, are the characteristic static
signatures associated with UNE. The P-wave velocity of the cavity system is 50 –
80 % lower than the initial background velocity. Certain dynamic signatures, such as groundwater mounding, are observable for a prolonged period, even for several
decades, due to the redistribution of residual stress, temperature, and saturation.
These dynamic phenomena are most prominent near the source origin, while their
spatial and temporal behaviour depends on the explosive yield strength, detonation
depth, and geology of the test site.
This study was carried out in four stages. The first stage investigates the characteristic phenomena associated with the UNE and their impact on the emplacement
rock’s seismic property. The dynamic phenomena of groundwater mound (GWM)
has a very high dissipation rate during the first 100 days following the explosion.
The numerical modelling study carried out for isotropic alluvium rock medium shows
that the GWM dissipation can cause about 40 % velocity change, which can be detected by time-lapse seismic. The target for active seismic survey in OSI is a cavity
(low velocity zone) created by UNE and associated GWM dynamic phenomena. In
the second stage of the research, a seismic processing workflow for detecting subsurface cavities is presented, and a frequent time-lapse seismic monitoring strategy
is proposed. The rate of dissipation of GWM; which is geology, yield strength and
rock permeability dependent; is at its peak during the initial days after UNE and
gradually drops. Conducting a frequent time-lapse seismic monitoring during the
period of high dissipation rate would increase the chance of detecting the time-lapse
change associated with GWM. Due to the time constraint, conventional time-lapse
seismic processing would not be suitable for the OSI activity. Therefore, machine
learning-based multi-vintage cross-equalisation and 4D detection workflow are presented in the third stage of the research. The near-real-time 4D detection workflow
using machine learning can be implemented during the OSI to identify the potential
source location or ground zero. In the final stage of the research, optimal survey
parameters and technologies to be considered for implementing a time-lapse seismic
survey during the OSI are discussed .Engineering and Physical Sciences Research Council (EPSRC) fundin
Developing a sustainable real estate framework for Bahrain
Get PDFSustainable development has become a widely studied and adopted concept within multiple
disciplines. However, achieving sustainable development remains debatable due to the
different sectoral natures. Sustainability is viewed within three spheres: the economy (profit),
society (people), and the environment (planet), considering sustainability impacts all three
dimensions. The three elements must be balanced to achieve sustainable development,
considering multiple challenges and obstacles related to fragmented regulatory structures,
financial budgets, public awareness, and government capacity. A solution towards successful
sustainable development implementations includes the development of unified multisectoral
and multilevel frameworks that act as scaffolding for developing sectors and market
regulation as they are vital in creating enabling or limiting environmental achieving
sustainable outcomes.
This study is designed to answer how a sustainable real estate framework can achieve a
sustainable real estate sector and contribute towards sustainable development. The study
demonstrates specific gaps in practical, sustainable real estate practice, such as a fragmented
regulatory structure supplemented by weak communication, coordination, and opportunities
for collaboration between governmental stakeholders and the private sector. The aim is to
develop a framework to promote sustainability practices within the industry and contribute
to achieving sustainable development goals in 2030. Firstly, the research gained an
understanding of the current Bahrain real estate regulatory framework in contrast to the UN’s
Sustainable Real Estate Framework guideline. This process allowed missing elements to be
identified as internal and external gaps within the existing framework. Secondly, interview
questions were developed to collect findings to verify observations via interviews with
stakeholders within Bahrain. The combination of these findings is channelled into developing
the framework to effectively improve practices within the real estate sector towards
achievable sustainable practices. Lastly, a qualitative validation process was applied to the
framework to assess functionality and effectiveness to achieve the expected outcome. The
framework bridges gaps highlighted throughout the research and contributes towards
practical, sustainable development applications in sustainable real estate
An investigation into psychosocial and educational predictors of entrepreneurial intentions of graduates - A study of the Centre of Entrepreneurial Development (CED) from Karachi (Pakistan)
Get PDFPeople join Entrepreneurship Education Programmes (EEPs) for several reasons which may include
gaining a certificate, learning new ideas or concepts, and/or starting their own business. One of the
main aims of EEPs is to prepare students for entrepreneurship. The aim of the current project is to
investigate entrepreneurial intentions in conjunction with the teaching methods deployed by the EEP
called Certificate in Entrepreneurship (CIE) Programme in the Centre of Entrepreneurial
Development (CED) Karachi. The project uses the well-established Theory of Planned Behaviour
(TPB, Ajzen, 1985) as a theoretical framework, and looks into the extended TPB factors that might
predict entrepreneurial intentions. We included psychosocial factors such as attitudes towards
becoming an entrepreneur, social norms, perceived behavioural control about becoming an
entrepreneur, and perceived effectiveness of the teaching methods adopted by the EEP, i.e., as case
studies, anecdotes, lectures, industry visits, seminars and networking events. To address the overall
aim of the study, we used a qualitative and quantitative approach, adopting the Francis et al. (2004)
procedure for the development of a TPB instrument. The First Stage of the project included
interviews (N=11) followed by open-ended questionnaires (N=12) with graduates of the CIE
program which allowed us to gather qualitative data concerning teaching methods and individuals’
motivations for starting their own business. The results of thematic analysis on the qualitative data
were then used, in the Second Stage, to develop an extended TPB instrument which included
measures for attitudes towards becoming an entrepreneur, social norms, perceived behavioural
control about becoming an entrepreneur, and attitudes towards teaching methods and entrepreneurial
intentions. The quantitative data (N=247) gathered from the extended TPB survey was used to
perform several regressions in order to determine the best predictors for entrepreneurial intentions.
Our findings suggest that using guest speakers, local cases and networking sessions are the most
impactful in influencing entrepreneurial intention of the CIE participants. Our results also showed
that, with the exception of subjective norms, attitudes towards becoming an entrepreneur and
perceived behavioural control mediate the relationship between these teaching methods and
entrepreneurial intentions. Theoretical and practical implications include extended TPB model
validation with teaching methods, mediating roles of attitude and perceived behavioural control,
cultural influence on subjective norms, a TPB instrument and practical recommendation for EEPs
that share similar socio-cultural context as CIE around the world
Quantification of margins and uncertainty (QMU) approach to reservoir management decision making under uncertainty
No full textAbstract and full text unavailable. Restricted access until 31.12.2026
Risk management practices among SMEs in Nigeria : contribution to business success
Get PDFEmpirical research on how SMEs manage risk in practice is very scant. However, given
the strategic contribution of SMEs to economic development and their susceptibility to
risks, a more active risk management (RM) practice is increasingly seen as critical to their
success and survival. Hence, this study explored how SMEs in Nigeria perceive and
practice risk management and the extent to which SME owners and managers attribute
their business success to RM practices.
The research adopted an exploratory, qualitative multiple-case study method, using 11
Lagos SMEs as case studies. Data collection was through semi-structured interviews with
23 owners and managers across the SMEs. These SMEs were purposively selected from
five sectors, namely: Education, Manufacturing, Wholesale/Retail Trade, Human Health
and Social Work, Accommodation and Food Services sectors, and have been operating
successfully between seven and 29 years. The interviews were augmented by document
analysis. Data collected were analysed through thematic and cross-case synthesis to
identify themes and patterns that emerged across all the SMEs.
Findings suggest that the SMEs are aware of the risk facing their business and recognise
the importance of actively engaging in RM. The research established that the SMEs carry
out RM activities without necessarily acknowledging them as such or utilising complex
RM tools and techniques. Strategies commonly used by the SMEs in mitigating risks
were identified as Monitoring and Supervision, Awareness Creation, Planning,
Stakeholder Management, Supplier Management, Partnership and Collaboration,
Insurance, Networking, Enforcement and Agreement. Most of the SMEs attributed their
existence, growth and expansion, waste/loss reduction and ease of access to bank loans
to their RM activities. The research also identified the motivating factors for the SMEs
to enhance their current RM procedures.
The research contributed to existing theory and knowledge on RM in SMEs from
Nigeria's perspective, with a focus on Lagos State. Another contribution is in the
suggested approaches through which the SMEs can improve awareness, understanding
and attitude to risk among all their managers and employees. Further, contributions were
made in the recommendations to policymakers and financial institutions on how to
support SME growth and development through RM considerations
An assessment of the assisted seismic history matching workflow, practical innovations and solutions
Get PDFIn hydrocarbon reservoir monitoring, assisted seismic history matching (ASHM) remains
a large and intractable problem. Despite advances in optimisation algorithms, quantification of uncertainty, data quality, data processing, computational resources and general
subsurface knowledge, practical implementations of assisted/automated seismic history
matching (ASHM) remain boutique and inflexible. Consideration of recent research on
ASHM problems highlights a single-minded focus on algorithmic solutions, that ignore
the broader perspective of ASHM as a multidisciplinary framework for improving subsurface models. This thesis expands the consideration of ASHM beyond the optimisation,
to propose a novel three-phase approach. ASHM is posed as a larger workflow that includes acquiring, evaluating and establishing an ASHM model (Phase 1), history matching
(Phase 2) and model evaluation and improvement (Phase 3). By taking a big picture perspective with respect to ASHM, additional value and patterns to workflows emerge that
will improve the adoption of ASHM within the subsurface industry, by offering pragmatic
and targeted guidance to development, evaluation and improvement around subsurface
models via ASHM
Amine bis(phenolate) complexes for the catalytic ring-opening polymerisation of rac-lactide
Get PDFThe catalytic ring-opening polymerisation of cyclic esters to form degradable
polymers is an intensely studied area of chemistry, however, many of the highly active
complexes synthesised for this purpose are sensitive to moisture. Therefore, the
development of more robust catalysts would be desirable. Unfortunately, methods of
stabilising the metal centres often results in a decrease of activity, therefore innovative
approaches to balance the activity with stability are required. One potential method to
stabilise the catalysts is the utilisation of reversible bridging interactions between the
metal centres, which can inhibit further reactions when the catalyst is not in use. In this
thesis, the formation of bridging interactions between the metal centres using carboxylic
acid functionalised amine bis(phenolate) ligands will be investigated. A modified
reaction pathway enabling the formation of previously unattainable enantiomerically pure
ethyl ester functionalised amine bis(phenol)s was developed, due to poor yields with
existing literature routes. These new proligands were then complexed to titanium forming
five novel aggregates bridged by carboxylate and oxo-bridges, where the nucleation was
found to vary with the steric bulk on the pendant arm. When coordinated to zirconium
seven novel complexes with various binding modes were formed and the coordination
arrangement explored through single crystal X-ray diffraction studies. It was found that
the coordination mode varied depending on various factors including the steric bulk on
the metal precursor, the length of the pendant arm of the ligand and the reaction
conditions. The majority of the complexes were found to be stable to air and moisture
for several months, supporting the initial hypothesis. When investigated for their activity
catalysing the ring opening polymerisation (ROP) of rac-lactide, the complexes were
found to have moderate activities and excellent control over the polydispersity (Ð < 1.30).
Coordinating the proligands to aluminium resulted in the formation of four monometallic
species. While this meant the complexes were less stable, the complexes were found to
be highly active in the ROP of rac-lactide producing polymers of > 25,000 Da in length
in six hours and produced isotactic PLA (Pi = 0.61). The original hypothesis that the
application of carboxylate groups to bridge between the metal centres could produce
stable complexes was correct, however, work remains to improve the activity of these
complexes, as shown by the Al complexes
Exploring the drivers of voluntary credit risk disclosure in Western European banks
Get PDFPurpose – This thesis contributes to the research of voluntary credit risk disclosure
drivers for financial companies. Credit risk is one of the most important banking risks,
and information on credit risk is crucial for assessing a bank’s risk level. Nonetheless,
research on incentives for voluntary credit risk disclosure (VCRD) is underdeveloped.
The author adds to the body of knowledge by providing empirical evidence concerning
drivers for bank’s voluntary credit risk disclosure.
Design/methodology/approach – The thesis investigates a sample of 93 Western
European banks that are observed from 2015 to 2018. The extent of VCRD is measured
by a custom disclosure index that is based on frontrunning a mandatory disclosure
guideline. Hypotheses on VCRD are defined based on a multi-theoretical framework that
employs agency, signalling, legitimacy and stakeholder theories. The link between these
drivers and VCRD is empirically tested by using a hybrid panel data model.
Findings – Bank size, credit risk level, listing status, being considered significant by the
European Central Bank and board independence are positively associated with voluntary
credit risk disclosure. Legitimacy concerns, banking supervision monitoring and
management signalling play a material role to influence VCRD decisions.
Research limitations/implications – Generalisation of the findings might be impacted
based on the geographic focus of the study and its short period of observation. The index
creation is depending on the ability of the EBA guideline to capture relevant credit risk
disclosures. Bank scoring inevitably incorporates a degree of subjectivity.
Practical implications – The thesis provides insights for banking regulators and
supervisors on how banks can be incentivised to increase VCRD and suggests
improvements for future credit risk disclosure policies and regulations.
Originality/value – The thesis investigates a set of VCRD drivers that have previously
not been tested, innovatively employing a new disclosure index and a quantitative
framework based on a hybrid panel model.
Keywords: Voluntary credit risk disclosure, banks, Western Europe, disclosure index,
hybrid model, agency theory, signalling theory, legitimacy theory, stakeholder theor
Female accountants in China : an alternative feminist discourse on the changing professional and gender identities
Get PDFWomen’s experiences in the accounting profession have attracted substantial attention in
the accounting literature. Most research in the gender and accounting fields is set in
Western contexts, therefore the relationship between women and accounting in non-Western contexts requires further exploration. This study is set in China to understand
how different generations of Chinese women accountants construct their professional and
gender identities. Theoretically, this study is framed by feminist poststructuralism to
identify dominant discourses on women and accounting in China and to further reveal
their discursive power on Chinese women accountants’ identity construction. Data is
collected by in-depth semi-structured interviews with 31 Chinese women accountants
from various backgrounds and generations.
This study identifies two dominant discourses on accounting professionals in China:
‘accountants are serious and cautious’ and ‘women are more suitable than men to work
as accountants’. The dominant discourses on the accounting profession have encouraged
generations of Chinese women to enter the accounting profession. Although Chinese
women accountants do not need to mimic men’s behaviour and outfits like their Western
counterparts, they are expected to perform in line with the traditional Confucian female
virtues. This suggests that the accounting profession in China has favoured women
because accounting roles and functions in China have been similar to traditional Chinese
women’s roles and functions in the family. However, the female-dominated accounting
profession in China does not provide women with the privilege or prestige enjoyed by
men in the male-dominated accounting profession in Western contexts. Gendered
discourses on women have still created gendered barriers in the workplace and
disadvantaged Chinese women accountants from progressing their careers to a higher
level.
This study further explores Chinese women accountants’ unique understanding of
professionalism. Chinese women accountants recognise having integrity, being
responsible and ethical as the most important factors for professional accountants.
Additionally, they are aware that the emotional and personal ties and strong obligations
involved in networking in China might threaten their integrity as professional accountants.
As a result, they often prioritise professional knowledge over networking.
Furthermore, this study finds that accounting professionals in China face a similar transformation as their Western counterparts – from the traditional accountant to the
hybrid business professional who is competent in management, consultancy and IT. As a
result, the distance between bookkeeping and accounting has increased in China. The
traditional career path for Chinese accountants (accounting clerk – accountant –
accounting supervisor – manager – chief accountant/partner) has been destabilised, which
has created increasing identity insecurity and more gendered barriers in the workplace for
Chinese women accountants. Nevertheless, many Chinese women accountants have
proactively taken this transformation as an opportunity to reconstruct their professional
identities and overcome gendered discourses.
This study contributes to the existing gender and accounting literature by revealing
generational differences between Chinese women accountants in their gender and
professional identities. This study finds that older generations tend to ignore or adopt
gendered barriers to gain acceptability in the workplace whereas younger generations of
Chinese women accountants often choose to resist them in the workplace. Older
generations tend to construct their identity as the ‘hard-worker’ while the younger
accountants prefer a balance between life and work and are not afraid of refusing to work
overtime. Women accountants from older generations tend to follow the informal
seniority and hierarchy rules in the workplace in order to progress in their career whereas
younger generations often play as the ‘rule-breakers’ because they understand seniority
rules as ‘redundant, formalistic and bureaucratic’ adding no additional value to the
accounting workplace. Additionally, this study shows conflicts in the workplace between
different generations of women accountants but also reveals women accountants’
sisterhood in overcoming gendered barriers together in the workplace.
Overall, this study works as an alternative discourse on accounting and women and sheds
light on the unique professionalisation process of accounting in a post-socialist Chinese
context. Future research should explore the dynamic relations between women and
accounting in different contexts and investigate what role accounting plays in supporting
or challenging cultural and social norms which produce gendered professional identity
and gender divisions in the workplace
Access Repository Dashboard
Do you manage ROS: The Research Output Service. Heriot-Watt University Edinburgh ? Access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard!