Crew scheduling of light rail transit in Hong Kong: From modeling to implementation

This work concerns the problem of crew scheduling for the Hong Kong Light Rail Transit (LRT), which together with Heavy Rail Transit, makes up the two divisions of Kowloon-Canton Railway Corporation. As of early 1996, LRT operates eight routes, two train depots and 57 stations on its operational network. It is rapidly expanding on routes, capacities and territorial coverage, hence pressing needs for timely constructions of crew schedules whenever passenger demand variations necessitate modifications in train timetables, typically every 3-4 months. Computer-assisted manual solutions from old software can take up to 1 month of painstaking work. Our project aims at automating this complex schedule construction, adopting a novel optimization modeling approach amenable for decomposition into separate solution stages by network and heuristics algorithms. The entire crew schedule can be constructed iteratively in less than half an hour on a PC. The implementation runs as a decision support tool, with contributions of an overwhelming reduction in human effort in crew schedule construction and a feasible and better (higher productivity rate) schedule, with possible further manual improvements that can be made. © 1998 Elsevier Science Ltd. All rights reserved.link_to_subscribed_fulltex

Cost-effectiveness analysis of a fixed-dose combination of indacaterol and glycopyrronium as maintenance treatment for COPD

Ming-Cheng Chan,1,* Elise Chia-Hui Tan,2 Ming-Chin Yang3,* 1Section of Chest Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan, Republic of China; 2National Research Institute of Chinese Medicine, Ministry of Health and Welfare, Taipei, Taiwan, Republic of China; 3Institute of Health Policy and Management, National Taiwan University, Taipei, Taiwan, Republic of China *These authors contributed equally to this work Objective: The aim of this study was to evaluate the cost-effectiveness of the long-acting beta-2 agonist (LABA)/long-acting muscarinic antagonist (LAMA) dual bronchodilator indacaterol/glycopyrronium (IND/GLY) as a maintenance treatment for COPD patients from the perspective of health care payer in Taiwan. Patients and methods: We adopted a patient-level simulation model, which included a cohort of COPD patients aged ≥40 years. The intervention used in the study was the treatment using IND/GLY, and comparators were tiotropium or salmeterol/fluticasone combination (SFC). Data related to the efficacy of drugs, incidence of exacerbation, and utility were obtained from clinical studies. Direct costs were estimated from claims data based on the severity of COPD. The cycle length was 6 months (to match forced expiratory volume in 1 second [FEV1] data), and the time horizons included 1, 3, 5, 10 years, and lifetime. Deterministic and probabilistic sensitivity analyses were conducted to test the robustness of the model results. Costs were expressed in US dollars with a discount rate of 3.0%. Results: Compared to tiotropium and SFC, the incremental cost-effectiveness ratios (ICERs) per quality-adjusted life year (QALY) gained of patients treated with IND/GLY were US$5,987 and US$14,990, respectively. One-way sensitivity analysis revealed that the improvement in FEV1 provided by IND/GLY, the distribution of patients with regard to the severity of COPD, and acute exacerbation rate ratio were the key drivers behind cost-effectiveness. Adopting a willingness to pay of US$60,000 per QALY gained as the threshold, there was a 98.7% probability that IND/GLY was cost-effective compared to tiotropium. Similarly, there was a 99.9% probability that IND/GLY was cost-effective compared to SFC. Conclusion: As a maintenance treatment for COPD, we consider the dual bronchodilator IND/GLY as a cost-effective strategy when compared to either tiotropium or SFC. Keywords: COPD, LABA/LAMA dual bronchodilator, indacaterol/glycopyrronium, maintenance therapy, cost-effectiveness, ICS/LABA combinatio

Optimization-based automatic parameter tuning for stereo vision

Paper We_2-T5.4Stereo vision is an important 3D sensing technique for producing dense point clouds required for robotic navigation and manipulation. It can provide excellent depth resolution at high frame rates and is potentially smaller, cheaper and consumes less power than systems using active sensor devices, due to its use of standard imaging components like cameras. However, stereo vision system can generate high quality point clouds only when its parameters are appropriately tuned. To tune these parameters manually is not only tedious but also challenging, due to the large number of parameters and their non-linear effect on the depth map quality. In this paper, we present an optimization-based method to automatically tune the stereo parameters. In particular, we first adjust the disparity range to ensure the entire scene can be covered in the resultant depth map, and then use non-linear optimization to refine other parameters for the optimal depth map quality. Our tuning process is efficient and can update adaptively according to changing environment. Experiments on the teleoperation tasks using the Atlas robot validate our approach, and demonstrate the improvement it brings for the teleoperation effectiveness. © IEEE Robotics & Automation Society

Functionalized alkynylplatinum(II) polypyridyl complexes for use as sensitizers in dye-sensitized solar cells

A series of platinum(II) alkynyl-based sensitizers has been synthesized and found to show light-to-electricity conversion properties. These dyes were developed as sensitizers for the application in nanocrystalline TiO 2 dye-sensitized solar cells (DSSCs). Their photophysical and electrochemical properties were studied. The excited-state property was probed using nanosecond transient absorption spectroscopy, which showed the formation of a charge-separated state that arises from the intramolecular photoinduced charge transfer from the platinum(II) alkynylbithienylbenzothiadiazole moiety (donor) to the polypyridyl ligand (acceptor). A lifetime of 3.4 μs was observed for the charge-separated state. A dye-sensitized solar cell based on one of the complexes showed a short-circuit photocurrent of 7.12 mAcm -2, an open circuit voltage of 780 mV, and a fill factor of 0.65, thus giving an overall power conversion efficiency of 3.6%. Electric company: A series of platinum(II) alkynyl-based sensitizers has been synthesized and found to show light-to-electricity conversion properties (see graphic). A dye-sensitized solar cell based on one of the complexes shows a fill factor of 0.65 and a power-conversion efficiency of 3.6%. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.link_to_subscribed_fulltex

Oxidative damage in ischemic stroke revealed using multiple biomarkers

Background and Purpose-We investigated changes in oxidative damage after ischemic stroke using multiple biomarkers. Methods-Serial blood and urine samples of ischemic stroke subjects and age-matched control subjects were assayed for F2-isoprostanes, hydroxyeicosatetraenoic acid products, F4-neuroprostanes, 24-hydroxycholesterol, allantoin, and urate. Results-Sixty-six stroke subjects (mean age, 65 years; median National Institutes of Health Stroke Scale 17) and 132 control subjects were recruited. A bimodal pattern of change was observed in plasma and urinary F2-isoprostanes and plasma 24-hydroxycholesterol. The rise in plasma hydroxyeicosatetraenoic acid products, F4-neuroprostanes, and allantoin was highest 6 to 12 hours after stroke onset, whereas plasma urate was significantly lower than controls on Days 1 to 3. After adjusting for age and baseline National Institutes of Health Stroke Scale, baseline plasma esterified hydroxyeicosatetraenoic acid products (OR, 1.01; 95% CI, 1.01 to 1.02), plasma urate (1.01; 1.00 to 1.01), and plasma free F4-neuroprostanes (2.73; 1.76 to 3.93) were associated with 90-day good functional recovery (modified Rankin Scale ≤1). Conclusions-Multiple markers of oxidative damage are increased immediately after stroke and remain elevated for several days. Recognition of these temporal changes may help design better antioxidant treatment trials for acute ischemic stroke. © 2011 American Heart Association, Inc.link_to_subscribed_fulltex