Well-Posedness, Conditioning and Regularization of Minimization, Inclusion and Fixed-Point Problems

AMS subject classification: 65K10, 49M07, 90C25, 90C48.

CVaR minimization by the SRA algorithm

Using the risk measure CV aR in �nancial analysis has become more and more popular recently. In this paper we apply CV aR for portfolio optimization. The problem is formulated as a two-stage stochastic programming model, and the SRA algorithm, a recently developed heuristic algorithm, is applied for minimizing CV aR.

CVaR számítás SRA algoritmussal (CVaR minimization by the SRA algorithm)

A CV aR kockázati mérték egyre nagyobb jelentőségre tesz szert portfóliók kockázatának megítélésekor. A portfolió egészére a CVaR kockázati mérték minimalizálását meg lehet fogalmazni kétlépcsős sztochasztikus feladatként. Az SRA algoritmus egy mostanában kifejlesztett megoldó algoritmus sztochasztikus programozási feladatok optimalizálására. Ebben a cikkben az SRA algoritmussal oldottam meg CV aR kockázati mérték minimalizálást. ___________ The risk measure CVaR is becoming more and more popular in recent years. In this paper we use CVaR for portfolio optimization. We formulate the problem as a two-stage stochastic programming model. We apply the SRA algorithm, which is a recently developed heuristic algorithm, to minimizing CVaR.

Makespan minimization in a job shop with a batch processing machine

A job shop with one batch processing and several discrete machines is analyzed. Given a set of jobs, their process routes, processing requirements, and size, the objective is to schedule the jobs such that the makespan is minimized. The batch processing machine can process a batch of jobs as long as the machine capacity is not violated. The batch processing time is equal to the longest processing job in the batch. The problem under study can be represented as Jm:batch:Cmax. If no batches were formed, the scheduling problem under study reduces to the classical job shop scheduling problem (i.e. Jm:: Cmax), which is known to be NP-hard. This research extends the scheduling literature by combining Jm::Cmax with batch processing. The primary contributions are the mathematical formulation, a new network representation and several solution approaches. The problem under study is observed widely in metal working and other industries, but received limited or no attention due to its complexity. A novel network representation of the problem using disjunctive and conjunctive arcs, and a mathematical formulation are proposed to minimize the makespan. Besides that, several algorithms, like batch forming heuristics, dispatching rules, Modified Shifting Bottleneck, Tabu Search (TS) and Simulated Annealing (SA), were developed and implemented. An experimental study was conducted to evaluate the proposed heuristics, and the results were compared to those from a commercial solver (i.e., CPLEX). TS and SA, with the combination of MWKR-FF as the initial solution, gave the best solutions among all the heuristics proposed. Their results were close to CPLEX; and for some larger instances, with total operations greater than 225, they were competitive in terms of solution quality and runtime. For some larger problem instances, CPLEX was unable to report a feasible solution even after running for several hours. Between SA and the experimental study indicated that SA produced a better average Cmax for all instances. The solution approaches proposed will benefit practitioners to schedule a job shop (with both discrete and batch processing machines) more efficiently. The proposed solution approaches are easier to implement and requires short run times to solve large problem instances.

Cooperative routing for collision minimization in wireless sensor networks

Cooperative communication has gained much interest due to its ability to exploit the broadcasting nature of the wireless medium to mitigate multipath fading. There has been considerable amount of research on how cooperative transmission can improve the performance of the network by focusing on the physical layer issues. During the past few years, the researchers have started to take into consideration cooperative transmission in routing and there has been a growing interest in designing and evaluating cooperative routing protocols. Most of the existing cooperative routing algorithms are designed to reduce the energy consumption; however, packet collision minimization using cooperative routing has not been addressed yet. This dissertation presents an optimization framework to minimize collision probability using cooperative routing in wireless sensor networks. More specifically, we develop a mathematical model and formulate the problem as a large-scale Mixed Integer Non-Linear Programming problem. We also propose a solution based on the branch and bound algorithm augmented with reducing the search space (branch and bound space reduction). The proposed strategy builds up the optimal routes from each source to the sink node by providing the best set of hops in each route, the best set of relays, and the optimal power allocation for the cooperative transmission links. To reduce the computational complexity, we propose two near optimal cooperative routing algorithms. In the first near optimal algorithm, we solve the problem by decoupling the optimal power allocation scheme from optimal route selection. Therefore, the problem is formulated by an Integer Non-Linear Programming, which is solved using a branch and bound space reduced method. In the second near optimal algorithm, the cooperative routing problem is solved by decoupling the transmission power and the relay node se- lection from the route selection. After solving the routing problems, the power allocation is applied in the selected route. Simulation results show the algorithms can significantly reduce the collision probability compared with existing cooperative routing schemes.

Student, Teacher, and Administrator Perspectives on Harm: Implications for Implementing Safe and Caring School Initiatives

This article reports on a study that examines student, teacher and administrator perspectives on harm and how their schools address harm. It presents an overview of these perspectives within and across 3 different school environments. In doing so, the study contributes to a better understanding of the often ineffective implementation of safe and caring school initiatives. By drawing on restorative justice and relational theory, the findings illustrate how a focus on well-being and relationship is critical for meeting the needs of those harmed and those causing harm. Such a focus requires interaction rooted in social engagement rather than social control (Morrison 2012) and challenges current recommendations for combining the strengths of several current approaches for a more effective outcome (Osher et al. 2010).

When expectancies harm comprehension : Encoding flexibility in impression formation

Peer reviewed

When expectancies harm comprehension : Encoding flexibility in impression formation

Peer reviewed

Minimization of radiation exposure due to computed tomography in inflammatory bowel disease

Patient awareness and concern regarding the potential health risks from ionizing radiation have peaked recently (Coakley et al., 2011) following widespread press and media coverage of the projected cancer risks from the increasing use of computed tomography (CT) (Berrington et al., 2007). The typical young and educated patient with inflammatory bowel disease (IBD) may in particular be conscious of his/her exposure to ionising radiation as a result of diagnostic imaging. Cumulative effective doses (CEDs) in patients with IBD have been reported as being high and are rising, primarily due to the more widespread and repeated use of CT (Desmond et al., 2008). Radiologists, technologists, and referring physicians have a responsibility to firstly counsel their patients accurately regarding the actual risks of ionizing radiation exposure; secondly to limit the use of those imaging modalities which involve ionising radiation to clinical situations where they are likely to change management; thirdly to ensure that a diagnostic quality imaging examination is acquired with lowest possible radiation exposure. In this paper, we synopsize available evidence related to radiation exposure and risk and we report advances in low-dose CT technology and examine the role for alternative imaging modalities such as ultrasonography or magnetic resonance imaging which avoid radiation exposure.

Self-cutting and prospective repetition of self-harm: studies of emergency department presentations in Ireland

Background Self-harm places an individual at increased risk of future self-harm and suicide, and indicates distress and maladaptive coping. Those who present to hospital with self-cutting form a significant minority of self-harm patients who are at increased risk of prospective repetition of self-harm and suicide compared with those presenting with intentional overdose. In addition to increased risk, there is emerging evidence of demographic, psychological, clinical, and social differences between those presenting with self-cutting and those presenting with overdose. Aim and Key Objectives The aim of the current doctoral work was to examine in detail the association between presenting with self-cutting and risk of prospective repetition. The objectives were: to identify evidence-based risk factors for repetition of self-harm among those presenting to emergency departments with self-harm; to compare demographic and presentation characteristics and prospective repetition across presentations of self-cutting only, self-cutting plus intentional overdose, and intentional overdose only; to compare prospective repetition and other characteristics within self-cutting presentations based on the type of treatment received; to compare self-cutting and intentional overdose patients on psychological risk and protective factors for repetition; and to examine the lived experience of engaging in repeated overdose and self-cutting. Methods The current doctoral work used a mixed-methods approach and is comprised of one systematic review and four empirical studies. The empirical studies were two registry-based prospective studies of Irish hospital presentations of self-harm, one prospective structured interview study, and one qualitative study using Interpretative Phenomenological Analysis. Results The systematic review identified several consistent and emerging risk factors for repetition of self-harm, compared to which self-cutting had a medium-sized effect. The registry studies demonstrated that the involvement of self-cutting, particularly less medically severe selfcutting, confers an increased risk of 1-month and 12-month repetition among Irish index selfharm presentations. The structured psychological study detected higher hopelessness and lower non-reactivity to inner experience among those presenting with self-cutting, and higher depression among those who repeated self-harm. Repeaters had lower baseline levels of protective psychological factors than non-repeaters and continued to have higher depression and hopelessness at follow-up. Finally, the qualitative study indicated that self-harm is a purposeful action taken in response to an overwhelming situation and is evaluated afterwards in terms of personal and social effects. Chosen method of self-harm seemed to be influenced by the desired outcome of the self-harm act, capability, accessibility and previous experience. Conclusion Despite limitations in terms of recruitment rates, the work presented in this thesis is innovative in examining the issue of the association between self-cutting and repetition from multiple perspectives. No one factor can reliably predict all repetition but self-cutting represents one consistent and easily detected risk factor for repetition. Those who present with self-cutting exhibit significant differences on demographic, clinical, and psychological variables compared with those presenting with intentional overdose, and seem to exhibit a more vulnerable profile. However, those who present with self-cutting do not form a discrete or homogenous group, and self-harm methods and levels of suicidal intent are liable to fluctuate over time.

Factors associated with self-cutting as a method of self-harm: findings from the Irish National Registry of Deliberate Self-Harm

Background: Research suggests that patients presenting to hospital with self-cutting differ from those with intentional overdose in demographic and clinical characteristics. However, large-scale national studies comparing self-cutting patients with those using other self-harm methods are lacking. We aimed to compare hospital-treated self-cutting and intentional overdose, to examine the role of gender in moderating these differences, and examine the characteristics and outcomes of those patients presenting with combined self-cutting and overdose. Methods: Between 2003 and 2010, the Irish National Registry of Deliberate Self-Harm recorded 42,585 self-harm presentations to Irish hospital emergency departments meeting the study inclusion criteria. Data were obtained on demographic and clinical characteristics by independent data registration officers. Results: Compared with overdose only, involvement of self-cutting (with or without overdose) was significantly more common in males than females, with an overrepresentation of males aged <35 years. Independent of gender, involvement of self-cutting (with or without overdose) was significantly associated with younger age, city residence, repetition within 30 days and repetition within a year (females only). Factors associated with self-cutting as the sole method were no fixed abode/living in an institution, presenting outside 9 a.m. to 5 p.m., not consuming alcohol and repetition between 31 days and 1 year (males only). Conclusion: The demographic and clinical differences between self-harm patients underline the presence of different subgroups with implications for service provision and prevention of repeated self-harm. Given the relationship between self-cutting and subsequent repetition, service providers need to ensure that adequate follow-up arrangements and supports are in place for the patient.

Suicide and deliberate self harm in older Irish adults

Background: Hospital-treated deliberate self harm and suicide among older adults have rarely been examined at a national level. Methods: The Irish Central Statistics Office provided suicide and undetermined death data for 1980-2006. The National Registry of Deliberate Self Harm collected data relating to deliberate self harm presentations made in 2006-2008 to all 40 Irish hospital emergency departments. Results: Rates of female suicide among older adults (over 55 years) were relatively stable in Ireland during 1980-2006 whereas male rates increased in the 1980s and decreased in more recent decades. Respectively, the annual male and female suicide and undetermined death rate was 22.1 and 7.6 per 100,000 in 1997-2006. Male and female deliberate self harm was 3.0 and 11.0 times higher at 67.4 and 83.4 per 100,000, respectively. Deliberate self harm and suicide decreased in incidence with increasing age. Deliberate self harm generally involved drug overdose (male: 72%; female 85%) or self-cutting (male: 15%; female 9%). The most common methods of suicide were hanging (41%) and drowning (29%) for men and drowning (39%) and drug overdose (24%) for women. City and urban district populations had the highest rates of hospital-treated self harm. The highest suicide rates were in urban districts. Conclusions: Older Irish adults have high rates of hospital-treated deliberate self harm but below average rates of suicide. Drowning was relatively common as a method of suicide. Restricting availability of specific medications may reduce both forms of suicidal behavior.

Group problem-solving skills training for self-harm: randomised controlled trial

Background: Rates of self-harm are high and have recently increased. This trend and the repetitive nature of self-harm pose a significant challenge to mental health services. Aims: To determine the efficacy of a structured group problem-solving skills training (PST) programme as an intervention approach for self-harm in addition to treatment as usual (TAU) as offered by mental health services. Method: A total of 433 participants (aged 18-64 years) were randomly assigned to TAU plus PST or TAU alone. Assessments were carried out at baseline and at 6-week and 6-month follow-up and repeated hospital-treated self-harm was ascertained at 12-month follow-up. Results: The treatment groups did not differ in rates of repeated self-harm at 6-week, 6-month and 12-month follow-up. Both treatment groups showed significant improvements in psychological and social functioning at follow-up. Only one measure (needing and receiving practical help from those closest to them) showed a positive treatment effect at 6-week (P = 0.004) and 6-month (P = 0.01) follow-up. Repetition was not associated with waiting time in the PST group. Conclusions: This brief intervention for self-harm is no more effective than treatment as usual. Further work is required to establish whether a modified, more intensive programme delivered sooner after the index episode would be effective.

Alcohol consumption and related harm among university students in Ireland

Aim: Alcohol consumption is a leading cause of global suffering. The harms caused by alcohol to the individual, their peers and the society in which they live provokes public health concern. Elevated levels of consumption and consequences have been noted in those aged 18-29 years. University students represent a unique subsection of society within this age group. University authorities have attempted to tackle this issue throughout the past decade. However, the issue persists. Thus, the aim of this study is to contribute to the evidence base for policy and practice in relation to alcohol harm reduction among third-level students in Ireland. Methods: A mixed methods approach was employed. A systematic review of the prevalence of hazardous alcohol consumption among university students in Ireland and the United Kingdom from 2002 to 2014 was conducted. In addition, a narrative synthesis of studies of drinking types evidenced among youths in western societies was undertaken. A cross-sectional study focused on university students’ health and lifestyle behaviours with particular reference to alcohol consumption was undertaken using previously validated instruments. Undergraduate students registered to one university in Ireland were recruited using two separate modes; classroom and online. Studies investigated the impact of mode of data collection, the prevalence of hazardous alcohol consumption and resultant adverse consequences for mental health and wellbeing. In addition a study using a Q-methodology approach was undertaken to gain a deeper understanding of the cultural factors influencing current patterns of alcohol consumption. Data were analysed using IBM SPPS statistics 20, Stata 12, MPLUS and PQ Method. Results: The literature review focusing on students’ alcohol consumption found that there has been both an increase in hazardous alcohol consumption among university students and a convergence of male and female drinking patterns throughout the past decade. Updating this research, the thesis found that two-thirds of university students consume alcohol at a hazardous level, detailing the range of adverse consequences reported by university students in Ireland. Finally, the heterogeneous nature of this drinking was described in a narrative synthesis exposing six types of consumption. The succeeding chapters develop this review further by describing three typologies of consumption, two quantitative and one quali-quantilogical. The quantitative typology describes three types of drinking for men (realistic hedonist, responsible conformer and guarded drinker) and four types for women (realistic hedonist, peer-influenced, responsible conformer and guarded drinker). The quali-quantilogical approach describes four types of consumption. These are defined as the ‘guarded drinker’, the ‘calculated hedonist’, the ‘peer-influenced drinker’ and the ‘inevitable binger’. Discussion: The findings of this thesis highlight the scale of the issue and provide up-to-date estimates of alcohol consumption among university students in Ireland. Hazardous alcohol consumption is associated with a range of harms to self and harms to others in proximity to the alcohol consumer. The classification of drinkers into types signal the necessity for university management, health promotion practitioners and public health policy makers to tackle this issue using a multi-faceted approach.

Researching suicide, attempted suicide and near-lethal self-harm by offenders in community settings: Challenges for future research

Suicide is a serious international health problem and is more likely to occur in vulnerable populations such as offenders. There is an abundance of research into suicides of prisoners, but few studies have been carried out on suicides of offenders serving community sentences. This article identifies and evaluates the limited research that is available. Recommendations for future research are made, including how in-depth interviews can provide important information about near lethal incidents from the service users’ perspective, and how international comparisons could be helpful in understanding this problem further.