63 research outputs found

    Application of selection hyper-heuristics to the simultaneous optimisation of turbines and cabling within an offshore windfarm

    Get PDF
    Global warming has focused attention on how the world produces the energy required to power the planet. It has driven a major need to move away from using fossil fuels for energy production toward cleaner and more sustainable methods of producing renewable energy. The development of offshore windfarms, which harness the power of the wind, is seen as a viable approach to creating renewable energy but they can be difficult to design efficiently. The complexity of their design can benefit significantly from the use of computational optimisation. The windfarm optimisation problem typically consists of two smaller optimisation problems: turbine placement and cable routing, which are generally solved separately. This paper aims to utilise selection hyper-heuristics to optimise both turbine placement and cable routing simultaneously within one optimisation problem. This paper identifies and confirms the feasibility of using selection hyper-heuristics within windfarm optimisation to consider both cabling and turbine positioning within the same single optimisation problem. Key results could not identify a conclusive advantage to combining this into one optimisation problem as opposed to considering both as two sequential optimisation problems.</p

    Inguinal hernia surgery in the Netherlands: are patients treated according to the guidelines?

    Get PDF
    Purpose In 2003, a dedicated Dutch committee developed vidence-based guidelines for the treatment of nguinal hernia (IH) in children and adults. The aim of this tudy was to describe trends in hernia care before and after he publication of the guidelines on IH surgery in the etherlands. ethods Originally, a retrospective baseline analysis of H surgery in 90 Dutch hospitals was performed among atients treated for IH in 2001. The results of this baseline nalysis were compared with a recently performed second nalysis of patients treated for IH in 2005. esults In children\\4 years of age, the study showed a ignificant decrease of contralateral explorations. In adults, he study showed that significantly more patients were reated with a mesh-based repair in 2005 (95.9 vs. 78.8%, <0.01eover, there was an increase of patients ith bilateral hernia treated with an endoscopic technique 41.5 vs. 22.3%, P<0.01) and more patients were treated n day surgery (53.5 vs. 38.6%, P<0.01). Lastly, a decline n operations performed for recurrent IH in adults was bserved (10.9 vs. 13.3%, P<0.01). onclusion This study showed that most patients with IH n the Netherlands were treated according to the main ecommendations of the Dutch evidence-based guidelines

    A cost-effectiveness analysis of a preventive exercise program for patients with advanced head and neck cancer treated with concomitant chemo-radiotherapy

    Get PDF
    In recent years, concomitant chemo-radiotherapy (CCRT) has become an indispensable organ preserving treatment modality for advanced head and neck cancer, improving local control and overall survival in several anatomical sites [1]. Unfortunately, CCRT can have a detrimental effect on many functions of the upper respiratory and digestive system. Sequellae such as pain, oedema, xerostomia and fibrosis negatively affect mouth opening (trismus), chewing, swallowing and speech [1]. Several studies investigating long-term effects of CCRT have concluded that swallowing and nutritional dysfunction tend to be persistent and can be severe [2-4]. Not surprisingly, therefore, CCRT can have a negative effect on patients‟ quality of life (QoL) [2]. Moreover, even before onset of treatment patients may already present with pain, impaired swallowing, trismus, aspiration, dietary restrictions and tube dependency, and loss of body weight, because the tumour may disrupt the normal anatomy and thus interfere with normal function [1]. Many studies refer to the importance of rehabilitation after, and even during treatment, in order to support and improve those functions [2]. However, as yet, few studies have investigated the effects of (preventive) rehabilitation exercises on the predictable and inevitable swallowing and mouth opening problems for this patient group. In addition, little is known about the costs and benefits of such exercise programs for head and neck cancer. As the clinical effectiveness is established [4], it is now relevant to embark on cost-effectiveness as a contribution to decision making on coverage. The aim of this study was to analyze the incremental cost-effectiveness for a preventive exercise program (PREP) versus usual care (UC) for patients with advanced head and neck cancer treated at the Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital (NKI-AVL)
    corecore