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

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

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

Semi-classical noise investigation for sub-40nm metal-oxide-semiconductor field-effect transistors

Device white noise levels in short channel Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) dictate the performance and reliability of high-frequency circuits ranging from high-speed microprocessors to Low-Noise Amplifiers (LNAs) and microwave circuits. Recent experimental noise measurements with very short devices demonstrate the existence of suppressed shot noise, contrary to the predictions of classical channel thermal noise models. In this work we show that, as the dimensions continue to shrink, shot noise has to be considered when the channel resistance becomes comparable to the barrier resistance at the source-channel junction. By adopting a semi-classical approach and taking retrospectively into account transport, short-channel and quantum effects, we investigate the partitioning between shot and thermal noise, and formulate a predictive model that describes the noise characteristics of modern devices

Laparoscopic cholecystectomy in adults with sickle cell disease

Background: Chronic hemolysis predisposes adults with sickle cell disease (SCD) to the formation of bilirubinate cholelithiasis. Methods: To study the impact of laparoscopic cholecystectomy (LC) on this groups, we reviewed our records of all patients with SCD and cholelithiasis treated electively from 1991 to 1999. During that period, 13 consecutive patients with SCD underwent elective LC for symptomatic cholelithiasis. Nine patients (69.2%) were managed with a preoperative transfusion regimen to achieve a hemoglobin value of greater than or equal to 10 g/dl, independent of hemoglobin S percentage. Five patients who presented with jaundice were referred for preoperative endoscopic retrograde cholangiopancreatography (ERCP), which identified choledocholithiasis in two of them. Three other patients underwent intraoperative cholangiography, which revealed common bile duct stones in one patient. Results: One patient developed pyrexia for 2 days. There were no vaso-occlusive crises or deaths. The mean hospital stay was 3.3 days. Conclusions: LC has proven to be a safe and efficacious method for the treatment of symptomatic cholelithiasis in this high-risk population. Hematologists are now more willing to refer early, well-prepared patients with SCD and uncomplicated gallbladder disease for elective LC

Haptic interaction in VR-based paracentesis simulation for dexterity enhancement and assessment

In this paper, we describe the development of an interactive virtual reality (VR) system that aims to realistically simulate specific paracentesis clinical procedures (particularly the procedure involved in the catheterization of the subclavian vein). A simplified elasto-static finite-element model is used for the physically based simulation of the deformable tissues, particularly skin deflection during needle insertion. The VR-based simulation is being coupled with a haptic feedback device to provide to the user realistic feeling of the interaction forces applied during the simulated paracentesis procedure. The system described is developed in the frames of a research project aiming to develop a larger-scale virtual environment simulator of emergency room (ER) scenarios and protocols for clinical skill training and assessment. © 2004, CARS and Elsevier B.V. All rights reserved

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

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