28 research outputs found

    A stochastic local search algorithm with adaptive acceptance for high-school timetabling

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    Automating high school timetabling is a challenging task. This problem is a well known hard computational problem which has been of interest to practitioners as well as researchers. High schools need to timetable their regular activities once per year, or even more frequently. The exact solvers might fail to find a solution for a given instance of the problem. A selection hyper-heuristic can be defined as an easy-to-implement, easy-to-maintain and effective 'heuristic to choose heuristics' to solve such computationally hard problems. This paper describes the approach of the team hyper-heuristic search strategies and timetabling (HySST) to high school timetabling which competed in all three rounds of the third international timetabling competition. HySST generated the best new solutions for three given instances in Round 1 and gained the second place in Rounds 2 and 3. It achieved this by using a fairly standard stochastic search method but significantly enhanced by a selection hyper-heuristic with an adaptive acceptance mechanism. © 2014 Springer Science+Business Media New York

    Deep sea tests of a prototype of the KM3NeT digital optical module

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    The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deepwaters of the Mediterranean Sea. This digital optical module has a novel design with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has been integrated in the ANTARES detector for in-situ testing and validation. This paper reports on the first months of data taking and rate measurements. The analysis results highlight the capabilities of the new module design in terms of background suppression and signal recognition. The directionality of the optical module enables the recognition of multiple Cherenkov photons from the same (40)Kdecay and the localisation of bioluminescent activity in the neighbourhood. The single unit can cleanly identify atmospheric muons and provide sensitivity to the muon arrival directions

    The effect of interactive multimedia on preoperative knowledge and postoperative recovery of patients undergoing laparoscopic cholecystectomy

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    Objectives: Aim of this study is the evaluation of the impact of a multimedia CD (MCD) on preoperative anxiety and postoperative recovery of patients undergoing elective laparoscopic cholecystectomy (LC). Methods: Sixty consecutive candidates for elective LC were randomly assigned to four groups. Group A included 15 patients preoperatively informed regarding LC through the MCD presented by Registered Nurse (RN). Patients in group B (n = 15) were informed through a leaflet. Patients in group C (n = 15) were informed verbally from a RN. Finally, the control Group D included 15 patients informed conventionally by the attending surgeon and anesthesiologist, as every other patient included in groups A, B, and C. Preoperative assessment of knowledge about LC was performed after each informative session through a questionnaire. Evaluation of preoperative anxiety was conducted using APAIS scale. Postoperative pain and nausea scores were measured using an NRS scale, 16 hours after the patient had returned to the ward. Results: Statistical processing of the results (single linear regression) showed that patients in groups A, B, and C achieved a higher knowledge score, less preoperative anxiety score and less postoperative pain and nausea, compared to Group D. In multiple regression analysis, group A had a higher knowledge score compared to the four groups (p < 0.001 r2 = 0.41). Conclusion: Informative sessions using MCD is an effective means of improving patient's preoperative knowledge, especially in day-surgery cases, like LC. © 2007 Schattauer GmbH

    Necessity of the Periodical Ultrasound Assessment of the Peripheral Venous System in Intensive Care Unit Patients

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    The utility of periodic sonographic assessment and monitoring for early diagnosis of deep vein thrombosis (DVT) in patients hospitalized in intensive care units (ICUs) was investigated. Of 314 patients hospitalized in an ICU over a 24-mo period, 248 were examined. The first examination of the patients was carried out within the first 48 h of ICU admission, and weekly examination followed until discharge. Peripheral veins were examined according to the general principles of the ultrasound study using the compression test in B-mode imaging (image to gray scale). The criterion for the absence or presence of a clot within the lumen was the presence or absence of full compressibility of the venous lumen, respectively. Intermittent compression was applied to multiple cross sections along the entire extent of the limbs. Three patients (1.2%) were diagnosed with sub-clinical DVT. The diagnoses were made on the third (sapheno-femoral junction), fourth (right internal jugular) and fifth (left gastrocnemius) weeks of hospitalization, respectively, although patients received full anticoagulation prophylaxis. DVT in a general-population ICU patient on anticoagulation prophylaxis did not seem to occur very frequently, and hence, regular ultrasound monitoring is not recommended. However, it may have value after the third week or in a selected population of ICU patients with very severe and/or multiple predisposing factors or who are not undergoing anticoagulant treatment because of contraindications. © 2018 Elsevier Lt
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