A database management capability for Ada

The data requirements of mission critical defense systems have been increasing dramatically. Command and control, intelligence, logistics, and even weapons systems are being required to integrate, process, and share ever increasing volumes of information. To meet this need, systems are now being specified that incorporate data base management subsystems for handling storage and retrieval of information. It is expected that a large number of the next generation of mission critical systems will contain embedded data base management systems. Since the use of Ada has been mandated for most of these systems, it is important to address the issues of providing data base management capabilities that can be closely coupled with Ada. A comprehensive distributed data base management project has been investigated. The key deliverables of this project are three closely related prototype systems implemented in Ada. These three systems are discussed

Performance related issues in distributed database systems

The key elements of research performed during the year long effort of this project are: Investigate the effects of heterogeneity in distributed real time systems; Study the requirements to TRAC towards building a heterogeneous database system; Study the effects of performance modeling on distributed database performance; and Experiment with an ORACLE based heterogeneous system

AN IFC-BASED FRAMEWORK FOR OPTIMIZING LEVEL OF PREFABRICATION IN INDUSTRIALIZED BUILDING SYSTEMS

Ph.DDOCTOR OF PHILOSOPH

Strategies to prevent Type 2 Diabetes in the postnatal period, in women with history of Gestational Diabetes Exploring different research methodologies based on dietary and pharmacological interventions

Aim and objectives The aim of this thesis is to investigate methods to prevent the progression to type 2 diabetes in the immediate postnatal period, in women diagnosed with gestational diabetes mellitus (GDM). The objectives of this thesis are to explore the views of pregnant women diagnosed with gestational diabetes and healthcare professionals, with regards to the use of an app in the postnatal period which will provide information about diet for type 2 diabetes prevention. The development of a protocol for a single-arm feasibility study on a Mediterranean-style diet for the prevention of type 2 diabetes in the postnatal period. To pilot the trial design and study processes and assess the feasibility of a large-scale trial on the effectiveness of a Mediterranean-style diet in postnatal period for type 2 diabetes prevention. To examine the acceptability of a Mediterranean-style diet for type 2 diabetes prevention in women taking part in a feasibility study and explore the opinions of women and healthcare professionals on trial processes. To develop a protocol for a pilot trial on metformin for the prevention of type 2 diabetes in the postnatal period. Pilot the trial design and study processes and assess the feasibility of a large-scale trial on the effectiveness of metformin in postnatal period for type 2 diabetes prevention. Methods The methods employed in this thesis include a cross-sectional survey, a single arm mixed method feasibility study with qualitative evaluation (which included the use of an app) and a mixed method randomised controlled double blind feasibility study with the use of metformin or placebo. Results Survey The survey demonstrated that app usage is part of everyday life, with 84% (85/101) of pregnant GDM women and 82% (71/87) of healthcare professionals using apps daily. All pregnant women who participated in this survey had a device by which they could access apps (100%, 101/101) and 95% (179/188) of the participants had a smartphone. The participants agreed that an app which provides dietary information in the postnatal period for diabetes prevention would be welcomed by postnatal women with GDM history. Single arm feasibility study on a Mediterranean-style diet for the prevention of T2D in the postnatal period (MERIT) A total of 69% (83/121) of eligible multi-ethnic women agreed to participate and 67% (56/83) of those initially recruited commenced the intervention. The last visit (12 months postnatally) was completed by 73.2% (41/56) of participants. A higher number of participants completed visit 2 (which is at 6 months postnatally) 80.4% (45/56), but this visit was completed remotely due to COVID-19 pandemic lockdown restrictions, whereas visit 3 was completed face-to-face. Participants had high engagement with the coach, both face-to-face and via phone-calls or text messages. Adherence based on the ESTEEM diet questionnaire was high at the end of the study. There was a trend of reduction of total dysglycaemia, and the participants weight was also reduced by 1.3kg, from visit 1 (6 to 13 weeks) to visit 3 (12 months postnatally). Clinical effectiveness discussion is exploratory due to the small sample size. The intervention and trial processes were acceptable to women and healthcare professionals, adherence was high when women had a supportive environment, provided by their family and the health coach. The group chat function was not successful in this study. Randomised double-blind placebo-controlled pilot trial on metformin for the prevention of T2D in the postnatal period (OMAhA) A total of 57.9% (175/302) of eligible multi-ethnic women agreed to take part in the study, out of those 82.3% (144/175) were randomised to receive metformin or placebo. The attendance rates for visits 2 (6 months) and 3 (12 months) were similar, with 54.6% (71/130) and 55.7 (64/115) attending each visit respectively. Due to the COVID-19 pandemic visit 3 was completed over the phone for 21.7% (39/115) of the participants which led to limited blood samples collection. Total dysglycaemia reduction was evident in the metformin group (18.3%) compared to the placebo group (24.7%) but this discussion is exploratory, and the study is not powered to measure effectiveness. The metformin group maintained their weight throughout the study, whereas the placebo group gained 400g. Adherence was 54.1% (participants who took at least 75% of the recommended dosage). The study was acceptable to both women and healthcare professionals, but the element of peer-support should be included in future studies. Conclusion It is feasible and acceptable to recruit women in the postnatal period in studies that are focused on diabetes prevention and introduce dietary or pharmacological interventions. The MERIT protocol will have to be revised to address how follow-up rates can be improved. The OMAhA protocol will also be revised to target improvement in adherence and follow-up rates. The COVID-19 pandemic lockdown restrictions and staffing issues have impacted data collection of both studies. More research is needed in this population with larger sample sizes to be able to prove efficacy. The strongest motivator that affects adherence and retention is the woman’s perception of her own risk of developing diabetes. Future studies should include the element of peer support and an education session about the risk of Type 2 Diabetes in postnatal period

Asymptotically optimal declustering schemes for 2-dim range queries

AbstractDeclustering techniques have been widely adopted in parallel storage systems (e.g. disk arrays) to speed up bulk retrieval of multidimensional data. A declustering scheme distributes data items among multiple disks, thus enabling parallel data access and reducing query response time. We measure the performance of any declustering scheme as its worst case additive deviation from the ideal scheme. The goal thus is to design declustering schemes with as small an additive error as possible. We describe a number of declustering schemes with additive error O(logM) for 2-dimensional range queries, where M is the number of disks. These are the first results giving O(logM) upper bound for all values of M. Our second result is a lower bound on the additive error. It is known that except for a few stringent cases, additive error of any 2-dimensional declustering scheme is at least one. We strengthen this lower bound to Ω((logM)(d−1/2)) for d-dimensional schemes and to Ω(logM) for 2-dimensional schemes, thus proving that the 2-dimensional schemes described in this paper are (asymptotically) optimal. These results are obtained by establishing a connection to geometric discrepancy. We also present simulation results to evaluate the performance of these schemes in practice

Multisite adaptive computation offloading for mobile cloud applications

The sheer amount of mobile devices and their fast adaptability have contributed to the proliferation of modern advanced mobile applications. These applications have characteristics such as latency-critical and demand high availability. Also, these kinds of applications often require intensive computation resources and excessive energy consumption for processing, a mobile device has limited computation and energy capacity because of the physical size constraints. The heterogeneous mobile cloud environment consists of different computing resources such as remote cloud servers in faraway data centres, cloudlets whose goal is to bring the cloud closer to the users, and nearby mobile devices that can be utilised to offload mobile tasks. Heterogeneity in mobile devices and the different sites include software, hardware, and technology variations. Resource-constrained mobile devices can leverage the shared resource environment to offload their intensive tasks to conserve battery life and improve the overall application performance. However, with such a loosely coupled and mobile device dominating network, new challenges and problems such as how to seamlessly leverage mobile devices with all the offloading sites, how to simplify deploying runtime environment for serving offloading requests from mobile devices, how to identify which parts of the mobile application to offload and how to decide whether to offload them and how to select the most optimal candidate offloading site among others. To overcome the aforementioned challenges, this research work contributes the design and implementation of MAMoC, a loosely coupled end-to-end mobile computation offloading framework. Mobile applications can be adapted to the client library of the framework while the server components are deployed to the offloading sites for serving offloading requests. The evaluation of the offloading decision engine demonstrates the viability of the proposed solution for managing seamless and transparent offloading in distributed and dynamic mobile cloud environments. All the implemented components of this work are publicly available at the following URL: https://github.com/mamoc-repo

The Anatomy of Design: Foundations, Models and Applications

Brazier, F.M.T. [Promotor]Treur, J. [Promotor

Dynamic Assembly for System Adaptability, Dependability, and Assurance

(DASASA) ProjectAuthor-contributed print ite