Identifying preferred solutions for multi-objective aerodynamic design optimization

 Aerodynamic designers rely on high-fidelity numerical models to approximate, within reasonable accuracy, the flow around complex aerodynamic shapes. The ability to improve the flow field behaviour through shape modifications has led to the use of optimization techniques. A significant challenge to the application of evolutionary algorithms for aerodynamic shape optimization is the often excessive number of expensive computational fluid dynamic evaluations required to identify optimal designs. The computational effort is intensified when considering multiple competing objectives, where a host of trade-off designs are possible. This research focuses on the development of control measures to improve efficiency and incorporate the domain knowledge and experience of the designer to facilitate the optimization process. A multi-objective particle swarm optimization framework is developed, which incorporates designer preferences to provide further guidance in the search. A reference point is projected on the objective landscape to guide the swarm towards solutions of interest. This point reflects the preferred compromise and is used to focus all computing effort on exploiting a preferred region of the Pareto front. Data mining tools are introduced to statistically extract information from the design space and confirm the relative influence of both variables and objectives to the preferred interests of the designer. The framework is assisted by the construction of time-adaptive Kriging models, for the management of high-fidelity problems restricted by a computational budget. A screening criterion to locally update the Kriging models in promising areas of the design space is developed, which ensures the swarm does not deviate from the preferred search trajectory. The successful integration of these design tools is facilitated through the specification of the reference point, which can ideally be based on an existing or target design. The over-arching goal of the developmental effort is to reduce the often prohibitive cost of multi-objective design to the level of practical affordability in aerospace problems. The superiority of the proposed framework over more conventional search methods is conclusively demonstrated via a series of experiments and aerodynamic design problems

Clinical essentialising: a qualitative study of doctors’ medical and moral practice

While certain substantial moral dilemmas in health care have been given much attention, like abortion, euthanasia or gene testing, doctors rarely reflect on the moral implications of their daily clinical work. Yet, with its aim to help patients and relieve suffering, medicine is replete with moral decisions. In this qualitative study we analyse how doctors handle the moral aspects of everyday clinical practice. About one hundred consultations were observed, and interviews conducted with fifteen clinical doctors from different practices. It turned out that the doctors’ approach to clinical cases followed a rather strict pattern across specialities, which implied transforming patients’ diverse concerns into specific medical questions through a process of ‘essentialising’: Doctors broke the patient’s story down, concretised the patient’s complaints and categorised the symptoms into a medical sense. Patients’ existential meanings were removed, and the focus placed on the patients’ functioning. By essentialising, doctors were able to handle a complex and ambiguous reality, and establish a medically relevant problem. However, the process involved a moral as well as a practical simplification. Overlooking existential meanings and focusing on purely functional aspects of patients was an integral part of clinical practice and not an individual flaw. The study thus questions the value of addressing doctors’ conscious moral evaluations. Yet doctors should be aware that their daily clinical work systematically emphasises beneficence at the expense of others—that might be more important to the patient

Dying on the Streets: Homeless Persons’ Concerns and Desires about End of Life Care

BACKGROUND: There is little understanding about the experiences and preferences at the end of life (EOL) for people from unique cultural and socioeconomic backgrounds. Homeless individuals are extreme examples of these overlooked populations; they have the greatest risk of death, encounter barriers to health care, and lack the resources and relationships assumed necessary for appropriate EOL care. Exploring their desires and concerns will provide insight for the care of this vulnerable and disenfranchised population, as well as others who are underserved. OBJECTIVE: Explore the concerns and desires for EOL care among homeless persons. DESIGN: Qualitative study utilizing focus groups. PARTICIPANTS: Fifty-three homeless persons recruited from agencies providing homeless services. MEASUREMENTS: In-depth interviews, which were audiotaped and transcribed. RESULTS: We present 3 domains encompassing 11 themes arising from our investigation, some of which are previously unreported. Homeless persons worried about dying and EOL care; had frequent encounters with death; voiced many unique fears, such as dying anonymously and undiscovered; favored EOL documentation, such as advance directives; and demonstrated ambivalence towards contacting family. They also spoke of barriers to EOL care and shared interventions to improve dying among the very poor and estranged. CONCLUSIONS: Homeless persons have significant personal experience and feelings about death, dying, and EOL care, much of which is different from those previously described in the EOL literature about other populations. These findings have implications not only for homeless persons, but for others who are poor and disenfranchised

Older adults' beliefs about physician-estimated life expectancy: a cross-sectional survey

BACKGROUND: Estimates of life expectancy assist physicians and patients in medical decision-making. The time-delayed benefits for many medical treatments make an older adult's life expectancy estimate particularly important for physicians. The purpose of this study is to assess older adults' beliefs about physician-estimated life expectancy. METHODS: We performed a mixed qualitative-quantitative cross-sectional study in which 116 healthy adults aged 70+ were recruited from two local retirement communities. We interviewed them regarding their beliefs about physician-estimated life expectancy in the context of a larger study on cancer screening beliefs. Semi-structured interviews of 80 minutes average duration were performed in private locations convenient to participants. Demographic characteristics as well as cancer screening beliefs and beliefs about life expectancy were measured. Two independent researchers reviewed the open-ended responses and recorded the most common themes. The research team resolved disagreements by consensus. RESULTS: This article reports the life-expectancy results portion of the larger study. The study group (n = 116) was comprised of healthy, well-educated older adults, with almost a third over 85 years old, and none meeting criteria for dementia. Sixty-four percent (n = 73) felt that their physicians could not correctly estimate their life expectancy. Sixty-six percent (n = 75) wanted their physicians to talk with them about their life expectancy. The themes that emerged from our study indicate that discussions of life expectancy could help older adults plan for the future, maintain open communication with their physicians, and provide them knowledge about their medical conditions. CONCLUSION: The majority of the healthy older adults in this study were open to discussions about life expectancy in the context of discussing cancer screening tests, despite awareness that their physicians' estimates could be inaccurate. Since about a third of participants perceived these discussions as not useful or even harmful, physicians should first ascertain patients' preferences before discussing their life expectancies

What is different about living alone with cancer in older age? A qualitative study of experiences and preferences for care

Background: Increasing numbers of older patients with advanced cancer live alone but there is little research on how well health services meet their needs. The aim of this study was to compare the experiences and future preferences for care between two groups of older people with cancer in their last year of life; those who live alone, and those who live with co-resident carers. Methods: In-depth qualitative interviews were conducted with 32 people aged between 70 and 95 years who were living with cancer. They were recruited from general practices and hospice day care, when the responsible health professional answered no to the question, of whether they would be surprised if the patient died within twelve months. Twenty participants lived alone. Interviews were recorded and transcribed and the data analysed using a Framework approach, focussing on the differences and commonalities between the two groups. Results: Many experiences were common to all participants, but had broader consequences for people who lived alone. Five themes are presented from the data: a perception that it is a disadvantage to live alone as a patient, the importance of relational continuity with health professionals, informal appraisal of care, place of care and future plans. People who lived alone perceived emotional and practical barriers to accessing care, and many shared an anxiety that they would have to move into a care home. Participants were concerned with remaining life, and all who lived alone had made plans for death but not for dying. Uncertainty of timescales and a desire to wait until they knew that death was imminent were some of the reasons given for not planning for future care needs. Conclusions: Older people who live alone with cancer have emotional and practical concerns that are overlooked by their professional carers. Discussion and planning for the future, along with continuity in primary care may hold the key to enhancing end-of-life care for this group of patients

Physical, social, psychological and existential trajectories of loss and adaptation towards the end of life for older people living with frailty: a serial interview study

Abstract Background The experiences of people with cancer and organ disease have been described across different dimensions of need as they approach death. Such information is lacking for frail older people approaching death, but could highlight how a palliative approach might be relevant for this population. Methods Cognitively intact, community dwelling adults considered to be moderately or severely frail were recruited from a medical day hospital. Those recruited nominated an informal carer and case-linked professional. Qualitative in-depth serial interviews with older people and their informal carers were conducted over an 18 month period, and single interviews with case-linked healthcare professionals. Interviews were recorded, transcribed and narrative analytical techniques were used to compile case studies. Results Thirty-four participants (13 patients, 13 informal carers and 8 healthcare professionals) completed 40 individual, 14 joint and 8 professional interviews. Five patients died during the study. The analysis highlighted a dynamic balance between losses and adaptations. Three typical patterns of multi-dimensional change emerged. 1) Maintenance of psychological and existential well-being with a gradual social decline mirroring the physical deterioration. 2) a gradual reduction in both psychological and existential well-being. 3) a marked downturn in social, psychological and existential well-being before death. Frail older people sustained their well-being through maintaining a sense-of-self, garnering support from carers and community structures, and focusing on living from day to day. Their well-being lessened when they lost their sense-of-self, feeling alienated from the world, and confused over the cause of their circumstances. Death remained distant and ‘undiagnosed’. Social and community frameworks were essential for supporting their well-being. Conclusions Multidimensional end-of-life trajectories for frail older people differed from those with other conditions. Alleviating psychological, social and existential distress should be a priority of care as frail older people reach the end of life. The current palliative care model is problematic for this group. Care should address future concerns and not necessarily involve a focus on death or place of death

Preference-based multiobjective particle swarm optimization for airfoil design

A significant challenge to the application of evolutionary multiobjective optimization (EMO) for transonic airfoil design is the often excessive number of computational fluid dynamic (CFD) simulations required to ensure convergence. In this study, a multiobjective particle swarm optimization (MOPSO) framework is introduced, which incorporates designer preferences to provide further guidance in the search. A reference point is projected onto the Pareto landscape by the designer to guide the swarm towards solutions of interest. The framework is applied to a typical transonic airfoil design scenario for robust aerodynamic performance. Timeadaptive Kriging models are constructed based on a high-fidelity Reynolds-averaged Navier- Stokes (RANS) solver to assess the performance of the solutions. The successful integration of these design tools is facilitated through the reference point, which ensures that the swarm does not deviate from the preferred search trajectory. A comprehensive discussion on the proposed optimization framework is provided, highlighting its viability for the intended design application

Analisi e modellazione del trasporto pedonale in aree urbana

Comunicazione all'interno del seminario "Metodi e tecnologie dell'ingegneria dei trasport

Designing airfoils using a reference point based evolutionary many-objective particle swarm optimization algorithm

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