Cost-sensitive rainfall thresholds for shallow landslides

The risk management of rainfall-induced landslides requires reliable rainfall thresholds to issue early warning alerts. The practical application of these thresholds often leads to misclassifications, either false negative or false positive, which induce costs for the society. Since missed-alarm (false negative) and false-alarm (false positive) cost may be significantly different, it is necessary to find an optimal threshold that accounts for and minimises such costs, tuning the false-alarm and missed-alarm rates. In this paper, we propose a new methodology to develop cost-sensitive rainfall thresholds, and we also analyse several factors that produce uncertainty, such as the accuracy of rainfall intensity values at landslide location, the time of occurrence, the minimum rainfall amount to define the non-triggering event, and the variability of cost scenarios. Starting from a detailed mapping of landslides that occurred during five large-scale rainfall events in the Italian Central Alps, we first developed rainfall threshold curves with a ROC-based approach by using both rain gauge and bias-adjusted weather radar data. Then, based on a reference cost scenario in which we quantified several cost items for both missed alarms and false alarms, we developed cost-sensitive rainfall threshold curves by using cost-curve approach (Drummond and Holte 2000). Finally, we studied the sensitivity of cost items. The study confirms how important is the information regarding rainfall intensity at the landslide site for the development of rainfall thresholds. Although the use of bias-corrected radar strongly improves these values, a large uncertainty related to the exact time of landslide occurrence still remains, negatively affecting the analysis. Accounting for the different missed-alarm and false-alarm misclassification costs is important because different combinations of these costs make an increase or decrease of the rainfall thresholds convenient. In our reference cost scenario, the most convenient threshold is lower than ROC-based thresholds because it seeks to minimise the number of missed alarms, whereas the missed-alarm costs are almost seven times greater than false-alarm costs. However, for different cost scenarios, threshold may vary significantly, as much as half an order of magnitude.

Tuning of a shunted electromagnetic vibration absorber based on the maximisation of the electrical power dissipated

This paper investigates a local tuning approach for a shunted electromagnetic vibration absorber, which is based on the maximisation of the electrical power dissipated by the coil and shunt components. The study considers a simplified problem with a single-degree-of-freedom mechanical hosting system, which is excited by a white noise stochastic force. The hosting system is equipped with a coil-magnet seismic transducer, which is connected to a resistive-inductive shunt. The study examines the effectiveness of the shunted electromagnetic vibration absorber with respect to the following cost functions. Firstly, the reference cost function, which is based on the minimisation of the time-averaged kinetic energy of the hosting system. Secondly, the local cost functions, which are based on: the maximisation of the time-averaged vibration power absorbed by the shunted electromagnetic vibration absorber; the maximisation of the time-averaged mechanical power dissipated by the electromagnetic transducer and the maximisation of the time-averaged electrical power dissipated by the coil and the shunt. The study shows that, provided the transducer is lightly damped, the local cost function based on the maximisation of the electrical power dissipated by the coil and the shunt gives the same optimal tuning parameters than the reference cost function. Therefore, provided the electromagnetic transducer is properly designed, the shunt can be suitably tuned by maximising the time-averaged electrical power dissipated by the coil and shunt. This is a rather appealing practical solution since it can be implemented locally without the need of measuring the response of the hosting system and also it can be implemented in the shunt circuit without the need of extra sensors.

Investigation of the economic impact of surgical site infection development in cardiovascular surgeries on the prospective payment system in Japan

The purpose of this study was to evaluate the economic burden of surgical site infections (SSIs) that are included in the category of clean operation in the field of cardiovascular surgery. In total, 2,583 patients who underwent cardiac surgeries at Juntendo University Hospital in Japan between April 2008 and March 2018 were investigated. Among them, 9 SSI cases were individually matched to non-SSI cases based on a combination of age group (in 5-year increments), gender, timing of hospitalization (in 2-year intervals), National Healthcare Safety Network (NHSN) Risk Index, main disease category, and length of stay (LOS) prior to surgery (with the difference of ≤2 days). SSI and non-SSI cases were compared in terms of median LOS and piecework reference cost (PRC). The median LOS was 30 days for SSI cases and 19 days for non-SSI cases (p

Apply Information System of Maritime Energy for Improving Performance in Taiwan’s Coast Guard

<p><em>Taiwan is not a member of the International Maritime Organization country, and the domestic business is also a multi-horse carriage. There is no integration and a single government department is responsible. Therefore, it is relatively difficult to check the relevant statistical inquiries, and the definition objects are also different. The information must be subject to the announcement of the International Maritime Organization. However, the data may be subject to statistical errors due to the construction of errors and omissions. The motivation of this paper is to roughly guess Coast Guard’s information system and maritime energy to discuss how to improve the work performance. Materials use and cost estimates are resolved for both developmental and implementation activities. In addition, enhanced services costs are resolved to with total and average costs of standard EAP services. These findings provide point of reference cost estimates for other EAPs that may be considering offering enhanced services.</em></p>

FASTmC: a suite of predictive models for non-reference-based estimations of DNA methylation

We describe a suite of predictive models, coined FASTmC, for non-reference, cost-effective exploration and comparative analysis of context-specific DNA methylation levels. Accurate estimations of true DNA methylation levels can be obtained from as few as several thousand short-reads generated from whole genome bisulfite sequencing. These models make high-resolution time course or developmental, and large diversity studies practical regardless of species, genome size and availability of a reference genome.

Minimisation des surcoûts dans un contexte hors délai : cas des projets de construction dans les pays en développement

Cost overruns are frequent in the construction industry. They become greater the more the construction project is delayed. In developing countries, this situation is recurring and constitutes a significant financial problem. In a time-overrun context, our objective is to find a method that can enable us to reduce the delay while minimizing the subsequent cost overruns. We thus developed a mathematical model named CCOMTOC (construction cost optimisation model in time-overrun context). The model was tested and results reveal that the reduction of cost overruns is effective. We showed that in a time-overrun context, according to the importance of delay penalties, we obtain two distinct situations. On the basis of the reference cost calculated for a maximum compression of tasks within the normal duration, we note that, for low delay penalties, the total cost after further delays to the estimated completion time decreases as we deviate from the initial completion time. On the other hand, for relatively high delay penalties, the cost first passes by a minimum before increasing regularly during the further delays to the estimated completion time.Key words: time overrun, optimization, linear programming, time skid, delay make-up, cost overrun.

Cost-efficiency of endoscopic and external dacryocystorhinostomy

Background:In most centres in the United Kingdom, endoscopic dacryocystorhinostomy is currently undertaken as a joint operation between ophthalmologists and otolaryngologists. The addition of an extra surgeon, the use of endoscopic equipment and the relatively lower success rate of this procedure made us compare endoscopic dacryocystorhinostomy and external dacryocystorhinostomy with regards to costs and income for our hospital.Methods:All 38 primary endoscopic dacryocystorhinostomy cases performed in our centre in 2001–2003 were retrospectively compared with the 49 external dacryocystorhinostomy cases performed in 1993–2000. Cost–income calculations were made based on: rate of local anaesthesia, success rate, rate of day case admission, hospital reference cost for dacryocystorhinostomy, and the income per case extracted from national tariffs (based on the Health Resources Group). Also, the average number of cases per session was used to calculate the income gained per session for each method.Results:The following rates between the endoscopic and the external dacryocystorhinostomy were found: local anaesthesia, 29 vs 6 per cent, respectively; day-case operation, 95 vs 12 per cent, respectively; and success rate, 87 vs 94 per cent, respectively. The average number of endoscopic dacryocystorhinostomy cases conducted in a single theatre session was twice that of external dacryocystorhinostomy cases. Endoscopic dacryocystorhinostomy generated approximately twice the income of external dacryocystorhinostomy (£6585 vs £3292, respectively).Conclusion:Endoscopic dacryocystorhinostomy is more cost-effective than external dacryocystorhinostomy, despite having a lower success rate and greater usage of resources, as the endoscopic procedure generates more income. This is mainly due to the higher number of cases per session and the higher rates of local anaesthesia and day case operations possible.