Multi-version Speculative Concurrency Control with Delayed Commit

This paper presents an algorithm which extends the relatively new notion of speculative concurrency control by delaying the commitment of transactions, thus allowing other conflicting transactions to continue execution and commit rather than restart. This algorithm propagates uncommitted data to other outstanding transactions thus allowing more speculative schedules to be considered. The algorithm is shown always to find a serializable schedule, and to avoid cascading aborts. Like speculative concurrency control, it considers strictly more schedules than traditional concurrency control algorithms. Further work is needed to determine which of these speculative methods performs better on actual transaction loads.

The Sensor Network Workbench: Towards Functional Specification, Verification and Deployment of Constrained Distributed Systems

As the commoditization of sensing, actuation and communication hardware increases, so does the potential for dynamically tasked sense and respond networked systems (i.e., Sensor Networks or SNs) to replace existing disjoint and inflexible special-purpose deployments (closed-circuit security video, anti-theft sensors, etc.). While various solutions have emerged to many individual SN-centric challenges (e.g., power management, communication protocols, role assignment), perhaps the largest remaining obstacle to widespread SN deployment is that those who wish to deploy, utilize, and maintain a programmable Sensor Network lack the programming and systems expertise to do so. The contributions of this thesis centers on the design, development and deployment of the SN Workbench (snBench). snBench embodies an accessible, modular programming platform coupled with a flexible and extensible run-time system that, together, support the entire life-cycle of distributed sensory services. As it is impossible to find a one-size-fits-all programming interface, this work advocates the use of tiered layers of abstraction that enable a variety of high-level, domain specific languages to be compiled to a common (thin-waist) tasking language; this common tasking language is statically verified and can be subsequently re-translated, if needed, for execution on a wide variety of hardware platforms. snBench provides: (1) a common sensory tasking language (Instruction Set Architecture) powerful enough to express complex SN services, yet simple enough to be executed by highly constrained resources with soft, real-time constraints, (2) a prototype high-level language (and corresponding compiler) to illustrate the utility of the common tasking language and the tiered programming approach in this domain, (3) an execution environment and a run-time support infrastructure that abstract a collection of heterogeneous resources into a single virtual Sensor Network, tasked via this common tasking language, and (4) novel formal methods (i.e., static analysis techniques) that verify safety properties and infer implicit resource constraints to facilitate resource allocation for new services. This thesis presents these components in detail, as well as two specific case-studies: the use of snBench to integrate physical and wireless network security, and the use of snBench as the foundation for semester-long student projects in a graduate-level Software Engineering course.

Towards Formalizing Java's Weak References

Weak references provide the programmer with limited control over the process of memory management. By using them, a programmer can make decisions based on previous actions that are taken by the garbage collector. Although this is often helpful, the outcome of a program using weak references is less predictable due to the nondeterminism they introduce in program evaluation. It is therefore desirable to have a framework of formal tools to reason about weak references and programs that use them. We present several calculi that formalize various aspects of weak references, inspired by their implementation in Java. We provide a calculus to model multiple levels of non-strong references, where a different garbage collection policy is applied to each level. We consider different collection policies such as eager collection and lazy collection. Similar to the way they are implemented in Java, we give the semantics of eager collection to weak references and the semantics of lazy collection to soft references. Moreover, we condition garbage collection on the availability of time and space resources. While time constraints are used in order to restrict garbage collection, space constraints are used in order to trigger it. Finalizers are a problematic feature in Java, especially when they interact with weak references. We provide a calculus to model finalizer evaluation. Since finalizers have little meaning in a language without side-effect, we introduce a limited form of side effect into the calculus. We discuss determinism and the separate notion of uniqueness of (evaluation) outcome. We show that in our calculus, finalizer evaluation does not affect uniqueness of outcome.

Hospital clinicians information behaviour and attitudes towards the 'Clinical Informationist': an Irish survey

Background: Hospital clinicians are increasingly expected to practice evidence-based medicine (EBM) in order to minimize medical errors and ensure quality patient care, but experience obstacles to information-seeking. The introduction of a Clinical Informationist (CI) is explored as a possible solution. Aims:  This paper investigates the self-perceived information needs, behaviour and skill levels of clinicians in two Irish public hospitals. It also explores clinicians perceptions and attitudes to the introduction of a CI into their clinical teams. Methods: A questionnaire survey approach was utilised for this study, with 22 clinicians in two hospitals. Data analysis was conducted using descriptive statistics. Results: Analysis showed that clinicians experience diverse information needs for patient care, and that barriers such as time constraints and insufficient access to resources hinder their information-seeking. Findings also showed that clinicians struggle to fit information-seeking into their working day, regularly seeking to answer patient-related queries outside of working hours. Attitudes towards the concept of a CI were predominantly positive. Conclusion: This paper highlights the factors that characterise and limit hospital clinicians information-seeking, and suggests the CI as a potentially useful addition to the clinical team, to help them to resolve their information needs for patient care.

Repairing wireless sensor network connectivity in damaged environments

A wireless sensor network can become partitioned due to node failure, requiring the deployment of additional relay nodes in order to restore network connectivity. This introduces an optimisation problem involving a tradeoff between the number of additional nodes that are required and the costs of moving through the sensor field for the purpose of node placement. This tradeoff is application-dependent, influenced for example by the relative urgency of network restoration. In addition, minimising the number of relay nodes might lead to long routing paths to the sink, which may cause problems of data latency. This data latency is extremely important in wireless sensor network applications such as battlefield surveillance, intrusion detection, disaster rescue, highway traffic coordination, etc. where they must not violate the real-time constraints. Therefore, we also consider the problem of deploying multiple sinks in order to improve the network performance. Previous research has only parts of this problem in isolation, and has not properly considered the problems of moving through a constrained environment or discovering changes to that environment during the repair or network quality after the restoration. In this thesis, we firstly consider a base problem in which we assume the exploration tasks have already been completed, and so our aim is to optimise our use of resources in the static fully observed problem. In the real world, we would not know the radio and physical environments after damage, and this creates a dynamic problem where damage must be discovered. Therefore, we extend to the dynamic problem in which the network repair problem considers both exploration and restoration. We then add a hop-count constraint for network quality in which the desired locations can talk to a sink within a hop count limit after the network is restored. For each new problem of the network repair, we have proposed different solutions (heuristics and/or complete algorithms) which prioritise different objectives. We evaluate our solutions based on simulation, assessing the quality of solutions (node cost, movement cost, computation time, and total restoration time) by varying the problem types and the capability of the agent that makes the repair. We show that the relative importance of the objectives influences the choice of algorithm, and different speeds of movement for the repairing agent have a significant impact on performance, and must be taken into account when selecting the algorithm. In particular, the node-based approaches are the best in the node cost, and the path-based approaches are the best in the mobility cost. For the total restoration time, the node-based approaches are the best with a fast moving agent while the path-based approaches are the best with a slow moving agent. For a medium speed moving agent, the total restoration time of the node-based approaches and that of the path-based approaches are almost balanced.

Performance metrics of an optical spectral imaging system for intra-operative assessment of breast tumor margins.

As many as 20-70% of patients undergoing breast conserving surgery require repeat surgeries due to a close or positive surgical margin diagnosed post-operatively [1]. Currently there are no widely accepted tools for intra-operative margin assessment which is a significant unmet clinical need. Our group has developed a first-generation optical visible spectral imaging platform to image the molecular composition of breast tumor margins and has tested it clinically in 48 patients in a previously published study [2]. The goal of this paper is to report on the performance metrics of the system and compare it to clinical criteria for intra-operative tumor margin assessment. The system was found to have an average signal to noise ratio (SNR) >100 and <15% error in the extraction of optical properties indicating that there is sufficient SNR to leverage the differences in optical properties between negative and close/positive margins. The probe had a sensing depth of 0.5-2.2 mm over the wavelength range of 450-600 nm which is consistent with the pathologic criterion for clear margins of 0-2 mm. There was <1% cross-talk between adjacent channels of the multi-channel probe which shows that multiple sites can be measured simultaneously with negligible cross-talk between adjacent sites. Lastly, the system and measurement procedure were found to be reproducible when evaluated with repeated measures, with a low coefficient of variation (<0.11). The only aspect of the system not optimized for intra-operative use was the imaging time. The manuscript includes a discussion of how the speed of the system can be improved to work within the time constraints of an intra-operative setting.

The contribution of qualitative research in designing a complex intervention for secondary prevention of coronary heart disease in two different healthcare systems

Background: Developing complex interventions for testing in randomised controlled trials is of increasing importance in healthcare planning. There is a need for careful design of interventions for secondary prevention of coronary heart disease (CHD). It has been suggested that integrating qualitative research in the development of a complex intervention may contribute to optimising its design but there is limited evidence of this in practice. This study aims to examine the contribution of qualitative research in developing a complex intervention to improve the provision and uptake of secondary prevention of CHD within primary care in two different healthcare systems.

Methods: In four general practices, one rural and one urban, in Northern Ireland and the Republic of Ireland, patients with CHD were purposively selected. Four focus groups with patients (N = 23) and four with staff (N = 29) informed the development of the intervention by exploring how it could be tailored and integrated with current secondary prevention activities for CHD in the two healthcare settings. Following an exploratory trial the acceptability and feasibility of the intervention were discussed in four focus groups (17 patients) and 10 interviews (staff). The data were analysed using thematic analysis.

Results: Integrating qualitative research into the development of the intervention provided depth of information about the varying impact, between the two healthcare systems, of different funding and administrative arrangements, on their provision of secondary prevention and identified similar barriers of time constraints, training needs and poor patient motivation. The findings also highlighted the importance to patients of stress management, the need for which had been underestimated by the researchers. The qualitative evaluation provided depth of detail not found in evaluation questionnaires. It highlighted how the intervention needed to be more practical by minimising administration, integrating role plays into behaviour change training, providing more practical information about stress management and removing self-monitoring of lifestyle change.

Conclusion: Qualitative research is integral to developing the design detail of a complex intervention and tailoring its components to address individuals' needs in different healthcare systems. The findings highlight how qualitative research may be a valuable component of the preparation for complex interventions and their evaluation.

The journey to concordance for patients with hypertension: a qualitative study in primary care

Objective: We aimed to explore, using qualitative methods, the perspectives of patients with hypertension on issues relating to concordance in prescribing.

Method: This study took place in NHS general practices in Northern Ireland. A purposeful sample of patients who had been prescribed anti-hypertensive medication for at least one year were invited to participate in focus groups or semi-structured interviews; data were analysed using constant comparison.

Main outcome measures: The perspectives of patients with hypertension on issues relating to concordance in prescribing.

Results: Twenty-five individuals participated in five focus groups; two participated in semi-structured interviews. Participants felt they could make valuable contributions to consultations regarding their management. They were prepared to negotiate with GPs regarding their medication, but most deferred to their doctor’s advice, perceiving doctors’ attitudes and time constraints as barriers to their greater involvement in concordant decision-making. They had concerns about taking anti-hypertensive drugs, were aware of lifestyle influences on hypertension and reported using personal strategies to facilitate adherence and reduce the need to take medication.

Conclusions: Participants indicated a willingness to be?involved in concordance in prescribing anti- hypertensive medication but needed health professionals to address their concerns and confusion about the nature of hypertension. These findings suggest that there is a need for doctors and other healthcare professionals with responsibility for prescribing to develop skills specifically to explore the beliefs and views underlying an individual’s medication use. Such skills may need to be developed through specific training programmes at both undergraduate and postgraduate level.

Nurses' perceptions of and satisfaction with the medication administration system in long-term-care homes

The purpose of this study was to explore nurses' perceptions of and level of satisfaction with the medication administration system in long-term care (LTC). The cross-sectional survey design included both quantitative and open-ended questions. Data were collected from licensed registered nurses (RNs) and registered practical nurses (RPNs) at 9 LTC residences in southwestern Ontario, Canada. Using independent sample f tests, the researchers found that RNs were significantly less satisfied than RPNs with their medication administration system, particularly with respect to safety issues. RNs identified a number of related barriers, including time constraints, poor packaging, insufficient drug information, prescription changes, lack of staff competency, and unwieldy medication carts. Implications for practice and policy are discussed, including recommendations for improving medication administration practices and for addressing the workload demands of LTC nurses. © McGill University School of Nursing.

New challenges faced by carers during their child's hospital admission under segregation

Introduction
This paper presents the results of a qualitative study of CF family carers at the Belfast Paediatric CF Centre. The aim of this study was to describe the carer experience of their child’s admission to hospital under segregated care arrangements, and to highlight the meaning of segregation and cross infection from the carer perspective.

Method
Carers of children with CF who were admitted for two week IV antibiotic treatment during the study period were eligible to participate in this qualitative study. A consecutive series of eligible carers were approached in order of admission and within the time constraints of KR who was present two days each week. Recruitment of carers ended when no new themes emerged. Ten carers, 9 mothers and 1 couple, were interviewed about their experiences (mean age of child: 11.8 years; range: 1-17 years). Interpretative Phenomenological Analysis (IPA) was used to analyse and interpret the interview data.

Results and discussion
Balancing demands and dilemmas was the main contextual theme or experience of being a carer of a child with CF, and particularly so during admission to hospital. Many decisions were required every day that resulted in ‘double binds’ comprising uncertainty and stress. Three secondary themes captured the essence of carers’ experiences specifically related to segregation: managing risk and uncertainty; the burden of admission; and getting through each day. These themes will be described with examples illustrating the challenges faced by carers during their child’s hospitalisation, and the impact of segregation upon carers.

Perceptions of the Nurse Practitioner Role in Facilitating the Implementation of an Onsite Pain Management Team in Long Term Care

Background: One strategy to improve pain management in long term care (LTC) is to optimize the emerging role of the nurse practitioner (NP) in LTC. The purpose of this sub study was to learn about the NP role in implementing an onsite, interdisciplinary Pain Team in the LTC home setting.

Methods: We used a case study design that included two NPs who worked at separate LTC homes. Each of the NPs completed a weekly questionnaire of pain-related activities that they engaged in over a one-year implementation period; and a diary, using critical reflection, about their experiences and strategies used to implement the Pain Team. Descriptive statistics and thematic content analysis were used to analyze the case study data.

Findings: NPs tended to be most engaged in pain assessment and collaborated more with licensed nurses and personal support workers; less with pharmacists. NPs were more involved in organizational level activities, such as participating in committee work or assisting with the development of policies and procedures about pain. NPs created palliative care and pain service protocols; engaged in policy development, in-servicing, quality assurance and advocacy; and encouraged best practices. NPs were challenged with time constraints for pain management and balancing other role priorities and felt that increased scope of practice for them was needed.

Conclusions: The results of this study highlight how NPs implemented a Pain Team in LTC which may be helpful to others interested in implementing a similar strategy to reduce residents’ pain.

Effect of feed space allowance and period of access to food on dairy cow performance

Two experiments were conducted to examine the ‘long-term’ effect of feed space allowance and period of access to feed on dairy cow performance. In Experiment 1, three horizontal feed space allowances (20, 40 and 60 cm cow−1) were examined over a 127-d period (14 cows per treatment). In Experiment 2, 48 dairy cows were used in a continuous design (10-week duration) 2 × 2 factorial design experiment comprising two horizontal feed space allowances (15 and 40 cm cow−1), and two periods of access to feed (unrestricted and restricted). With the former, uneaten feed was removed at 08·00 h, while feeding took place at 09·00 h. With the latter, uneaten feed was removed at 06·00 h, while feeding was delayed until 12·00 h. Mean total dry-matter (DM) intakes were 19·0, 18·7 and 19·3 kg cow−1 d−1 with the 20, 40 and 60 cm cow−1 treatments in Experiment 1, and 18·1 and 18·2 kg cow−1 d−1 with the ‘restricted feeding time’ treatments, and 17·8 and 18·1 kg d−1 with the ‘unrestricted feeding time’ treatments (15 and 40 cm respectively) in Experiment 2. None of milk yield, milk composition, or end-of-study live weight or condition score were significantly affected by treatment in either experiment (P > 0·05), while fat + protein yield was reduced with the 15-cm treatment in Experiment 2 (P < 0·05). When access to feed was restricted by space or time constraints, cows modified their time budgets and increased their rates of intake.

Best Practice for Providing Social Care and Support to People Living with Concurrent Sight Loss and Dementia: Professional Perspectives

Purpose-Approximately 100,000 people in the UK aged 75 and over have concurrent dementia and sight loss, but current understanding of their experiences, needs and preferences is limited. The purpose of this paper is to report on a research project that explored the provision of social care and support for older people with both conditions. Design/methodology/approach-The project was a collaboration between the universities of York, Worcester, Bournemouth and Cambridge, supported by the Thomas Pocklington Trust and the Housing and Dementia Research Consortium. Data for this paper were drawn from focus groups held in 2013 involving 47 professionals across the dementia, sight loss and housing sectors. Findings-Thematic analysis identified five main barriers to providing high-quality, cost-effective social care and support: time constraints; financial limitations; insufficient professional knowledge; a lack of joint working; and inconsistency of services. The requirements of dementia and sight loss often conflict, which can limit the usefulness of equipment, aids and adaptations. Support and information needs to address individual needs and preferences. Research limitations/implications-Unless professionals consider dementia and sight loss together, they are unlikely to think about the impact of both conditions and the potential of their own services to provide effective support for individuals and their informal carers. Failing to consider both conditions together can also limit the availability and accessibility of social care and support services. This paper is based on input from a small sample of self-selecting professionals across three geographical regions of England. More research is needed in this area. Practical implications-There are growing numbers of people living with concurrent dementia and sight loss, many of whom wish to remain living in their own homes. There is limited awareness of the experiences and needs of this group and limited provision of appropriate services aids/adaptations. A range of measures should be implemented in order to support independence and well-being for people living with both conditions and their family carers. These include increased awareness, improved assessment, more training and greater joint working. Social implications-People living with dementia or sight loss are at high risk of social isolation, increasingly so for those with both conditions. Services that take an inclusive approach to both conditions can provide crucial opportunities for social interaction. Extra care housing has the potential to provide a supportive, community-based environment that can help residents to maintain social contact. Originality/value-This paper adds much-needed evidence to the limited existing literature, and reflects the views of diverse professionals across housing, health and social care

Using a whole person approach to support people with cancer: a longitudinal, mixed methods service evaluation

Introduction: Improved models of care are needed to meet all the support needs of people with cancer, which encompass psychological, emotional, physical, spiritual, sexual, occupational, social and existential needs. The aim of this paper is to (1) evaluate short and long-term impacts of using a whole person approach to support people with cancer on the Living Well with the Impact of Cancer Course (LWC); (2) use these data to inform strategic decisions about future service provision at Penny Brohn UK. Methods: Longitudinal mixed-methods service evaluation (n=135). Data collected included health related quality of life (HRQoL) (FACIT-SpEx); Concerns (types and severity - MYCaW); lifestyle behaviour (bespoke questionnaire) and participants’ experiences over 12 months post course. Results: Statistically and clinically significant improvements from baseline - 12 months in severity of MYCaW Concerns (n=64; p<0.000) and mean total HRQoL (n=66; p<0.000). The majority of MYCaW concerns were ‘psychological and emotional’ and about participants’ wellbeing. Spiritual, emotional and functional wellbeing contributed most to HRQoL improvements at 12 months. Barriers to maintaining healthy lifestyle changes included lack of support from family and friends, time constraints, and returning to work. 3-6 months post-course was identified as the time when more support was most likely to be needed. Conclusions: Using a whole person approach for the LWC enabled the needs of participants to be met, and statistically and clinically significant improvements in HRQoL and MYCaW Concerns were reported. Qualitative data analysis explored how experiencing whole person support enabled participants to make and sustain healthy lifestyle changes associated with improved survivorship. Barriers experienced to making health behaviour change were also identified. These data then informed wider and more person-centred clinical provision to increase the maintenance of positive long-term behaviour changes. Comparison of whole person approaches to cancer treatment and support and standard care are now urgently needed.