Predefined Limits Research Articles

Humanitarian relief network assessment using collaborative truck-and-drone system

The increasing number and severity of natural and man-made disasters worldwide has led to calls for more precise and effective humanitarian responses, and the use of humanitarian relief network assessment to reduce disaster uncertainty can play a vital role in the delivery of precise humanitarian operations. In this study, a collaborative truck-and-drone system was developed as a post-disaster assessment tool for use by humanitarian relief networks. The proposed system comprises a drone equipped with a camera that can launch from a truck to collect information from both nodes and links of a post-disaster transportation network. Following drone operation, the truck is used to retrieve and recharge the drone’s battery. To optimize this collaborative truck-and-drone system, we focused on the routing problem with the objective of maximizing the value of information collected from nodes and links within a predefined time limit, a problem made challenging by the need to determine the routes of the truck and drone in an integrated manner. To the best of our knowledge, this study was the first to consider the problem of collaborative truck-and-drone routing optimization with the goal of profit maximization. After formulating the proposed problem as a mixed-integer linear programming (MILP) model, we decomposed the problem structure into a path-based master problem and two sub-problems to allow the use of a column generation (CG) framework to tackle the problem. Numerical experiments were conducted to examine the proposed model and algorithm at various instance sizes that were generated by modifying an existing benchmark, with the results indicating that the proposed algorithm can obtain high-quality solutions with optimality gaps of less than 10% for all terminated instances within predefined time limit. A real-world instance—the Kartal district of Istanbul—was then used to demonstrate the practicality of the proposed model. Finally, the results of the numerical analysis were used to develop managerial insights for application by humanitarian relief agencies.

Remimazolam: A Review in Procedural Sedation.

Remimazolam (Byfavo™) is a benzodiazepine sedative that is indicated for the induction and maintenance of procedural sedation in adults. Remimazolam was efficacious in three phase III trials in patients requiring endoscopies. Significantly higher procedure success rates (composite of the completion of the procedure, top-up doses of study drug within predefined limits and no requirement for rescue therapy) were observed with remimazolam than with placebo, with the majority of placebo recipients requiring rescue midazolam. Furthermore, remimazolam significantly reduced times to onset of sedation and recovery in comparison with placebo (plus rescue). Remimazolam is generally well tolerated, with hypotension and hypertension the most common adverse drug reactions. Higher doses of concomitant fentanyl with remimazolam may increase the incidence of adverse drug reactions and deep sedation events. However, no correlation was observed between depth of sedation and vital signs. In summary, remimazolam is a useful option for the induction and maintenance of procedural sedation. Although pharmacoeconomic analyses for remimazolam are not yet available, the rapid induction of sedation and short recovery times with remimazolam may be beneficial in improving patient throughput in clinics.

Rapid-flow expulsion maneuver in subglottic secretion clearance to prevent ventilator-associated pneumonia: a randomized controlled study

BackgroundFollowing endotracheal intubation, clearing secretions above the endotracheal tube cuff decreases the incidence of ventilator-associated pneumonia (VAP); therefore, subglottic secretion drainage (SSD) is widely advocated. Our group developed a novel technique to remove the subglottic secretions, the rapid-flow expulsion maneuver (RFEM). The objective of this study was to explore the effectiveness and safety of RFEM compared with SSD.MethodsThis study was a single-center, prospective, randomized and controlled trial, conducted at Respiratory Intensive Care Unit (ICU) of Beijing Chao-Yang Hospital, a university-affiliated tertiary hospital. The primary outcome was the incidence of VAP, assessed for non-inferiority.ResultsPatients with an endotracheal tube allowing drainage of subglottic secretions (n = 241) were randomly assigned to either the RFEM group (n = 120) or SSD group (n = 121). Eleven patients (9.17%) in the RFEM group and 13 (10.74%) in the SSD group developed VAP (difference, − 1.59; 95% confidence interval [CI] [− 9.20 6.03]), as the upper limit of 95% CI was not greater than the pre-defined non-inferiority limit (10%), RFEM was declared non-inferior to SSD. There were no statistically significant differences in the duration of mechanical ventilation, ICU mortality, or ICU length of stay and costs between groups. In terms of safety, no accidental extubation or maneuver-related barotrauma occurred in the RFEM group. The incidence of post-extubation laryngeal edema and reintubation was similar in both groups.ConclusionsRFEM is effective and safe, with non-inferiority compared to SSD in terms of the incidence of VAP. RFEM could be an alternative method in first-line treatment of respiratory ICU patients.Trial registration This study has been registered on ClinicalTrials.gov (Registration Number: NCT02032849, https://clinicaltrials.gov/ct2/show/NCT02032849); registered on January 2014

Numerical and Experimental Modal Analysis of Wheels of Solaris 10 Solar Car and Parametric Design of Lightweight EV Wheel

In this study, the natural frequencies of Solaris 10 Solar Car’s 2018 and 2019-Model wheels were determined experimentally by the impact hammer test under free-free boundary conditions and the results were compared with the natural frequency results obtained using ANSYS FEA software. Comparing the numerical and experimental vibration analysis, a maximum percent error of 7.46% was observed. The 7th and upper mode frequencies of 2018 and 2019 wheel models were shown to be above 200 Hz and the experimental results were validated. After expressing the mode shapes in the ANSYS-Modal Analysis, a parametric study was performed for the 2019 wheel model using the ANSYS- Parametric Design. As a result of the parametric design, the mass of the 2019 wheel model was decreased by 6.5% while maximum equivalent von Mises stress was decreased by 2%. Thus, a lighter wheel design was obtained with ANSYS FEA software and maximum equivalent von Mises stress value was achieved to be below pre-defined limit of 120 (MPa).

Repeated radiation damage and thermal annealing of avalanche photodiodes

Avalanche photodiodes (APDs) are well-suited for single-photon detection on quantum communication satellites as they are a mature technology with high detection efficiency without requiring cryogenic cooling. They are, however, prone to significantly increased thermal noise caused by in-orbit radiation damage. Previous work demonstrated that a one-time application of thermal annealing reduces radiation-damage-induced APD thermal noise. Here we examine the effect of cyclical proton irradiation and thermal annealing. We use an accelerated testing environment which emulates a realistic two-year operating profile of a satellite in low-Earth-orbit. We show that repeated thermal annealing is effective at maintaining thermal noise of silicon APDs within a range suitable for quantum key distribution throughout the nominal mission life, and beyond. We examine two strategies—annealing at a fixed period of time, and annealing only when the thermal noise exceeds a pre-defined limit. We find both strategies exhibit similar thermal noise at end-of-life, with a slight overall advantage to annealing conditionally. We also observe that afterpulsing probability of the detector increases with cumulative proton irradiation. This knowledge helps guide design and tasking decisions for future space-borne quantum communication applications.

Comparison of point-of-care device DiaSpect against the HemoCue and laboratory analyser in an ICU population

Background: Haemoglobin levels guide many diagnostic and therapeutic interventions. They form part of the basic daily management of ICU patients. Laboratory results are frequently delayed. This can have important clinical consequences, including withholding potentially life-saving interventions. Point-of-care devices, if accurate, provide a solution to this problem. Inaccurate devices may provide misleading results leading to unnecessary and hazardous blood transfusions or under-estimation of disease severity. The aim was to compare the accuracy and reliability of the DiaSpect Hemoglobin T (DiaSpect. Medical GmbH, Sailauf, Germany) haemoglobinometer with the HemoCue (HemoCue AB, Angelholm Sweden) haemoglobinometer and the gold standard laboratory analyser for this trial (XT-200i Sysmex/Coulter LH750). Methods: Venous blood samples were collected via a central venous line from Intensive Care Unit (ICU) patients (n = 265) for determination of haemoglobin (Hb) concentration by DiaSpect as well as the HemoCue, and the automated haemoglobin analysers: XT-200i Sysmex or the Coulter LH750. Agreement between the methods was tested using Bland–Altman plots. A Hb variation of 0.5 g/dl was considered clinically significant. There were a significant number of wasted samples with the DiaSpect, as a total of 350 cuvettes were used but only 214 complete samples obtained. This wastage was attributed to errors in sampling, cuvette shortage, lack of experience with the device and lack of ‘user-friendliness’. Results: A total of 265 samples were obtained, of which 207 had complete data sets and were analysed further in the study. There were 58 incomplete samples, of which 51 were DiaSpect samples. Mean haemoglobin was 9.11 (standard deviation ± 1.74), 9.07 (standard deviation ± 1.96) and 9.02 (standard deviation ± 2.06) using the laboratory analyser, HemoCue and DiaSpect respectively. Laboratory and HemoCue: the mean difference between the two readings was -0.04 (95% limits of agreement -2.15 to 2.07 g/dl) with an average between 5.00 g/dl and 15.10 g/dl. Laboratory and DiaSpect: the mean difference between the readings was -0.09 (95% limits of agreement -2.64 to 2.46 g/dl) with an average between 5.10 g/dl and 14.9 g/dl. HemoCue and DiaSpect: the mean difference between the two haemoglobin levels was 0.04 (95% limits of agreement 2.73 to -2.64 g/dl). Both methods returned measurements within the pre-defined clinical acceptable limits of ± 0.5 g/dl. Conclusion: The haemoglobin concentration assessment by the HemoCue and DiaSpect showed an acceptable limit of agreement when compared against the laboratory analyser. There were a significant number of wasted samples when using the DiaSpect.

Studi Kelayakan Gas Insulated Switchgear di PT. Paiton Operation & Maintenance Indonesia Unit 8

Protection systems are a collection of components that have the same purpose to protect or secure. One of the existing protection systems in the generator is switchgear. At PT. Paiton Operation & Maintenance Indonesia Unit 8 using a switchgear insulated with SF6 gas is called gas insulated switchgear. Gas Insulated Switchgear is the newest of the switchyard innovations. Innovations that have been developed from air insulation into gas insulation have fewer land use advantages and a better level of density. In determining the feasibility of gas insulated switchgear PT. Paiton Operation & Maintenance Indonesia performs tests consisting of insulation resistance measurements, resistance measurements, gas leakage checks, polarity checking, gas density detectors, testing duration closure and circuit breaker opening. Each test has a pre-defined value limit. Gas Insulated switchgear is said to be feasible to operate when it meets the specified value limits on each test.

Modeling and Mitigation Control of the Submodule-Capacitor Voltage Ripple of a Modular Multilevel Converter under Unbalanced Grid Conditions

A modular multilevel converter’s (MMC’s) submodule (SM)-capacitor voltage will increase under unbalanced grid conditions. Depending on the imbalance level, the voltage ripple can be considerably high, and it can exceed the pre-defined safe limits. If this occurs, the converter will trip, which can lead to serious stability problems for the grid. This paper first proposes an analytical solution for deriving the three-phase imbalanced SM ripple of an MMC under an unbalanced grid. With this analytical tool, the imbalance mechanism of the SM voltage ripple can be easily understood. What is more, the symmetrical component method is first applied to analyze the three-phase SM capacitor ripple, and the positive-/negative-/zero-sequence components of the three-phase SM voltage ripple are easily identified by the proposed analytical method. Then, based on this powerful analytical tool, the proper circulating-current profile to be injected can be obtained, allowing for the right compensation of the voltage ripple. Based on this approach, two new voltage ripple compensation methods are proposed in this paper. Simulations were carried out to validate the analytical description of the submodule-capacitor voltage ripple proposed in this paper. Moreover, simulation and experimental results are provided to validate the new compensation techniques introduced in this paper.

Safety and feasibility of an intensive epilepsy nurse-based treatment course

PurposeTo determine safety, feasibility and patient satisfaction of an epilepsy nurse-based treatment course with frequent contacts and changes of anti-epileptic treatment provided by supervised anti-epileptic drug (AED) prescribing epilepsy nurses. MethodsRegular prescheduled clinical contacts with a neurologist to adjust AED treatment were largely substituted by on-demand contacts with epilepsy nurses with the delegated right to adapt AED within predefined limits. To secure safety, electronic medical files of patients with 6 or more contacts with epilepsy nurses were retrospectively analysed for clinical characteristics, safety measures and seizure frequency before/after the intensive treatment course and patients were asked to complete a questionnaire about treatment satisfaction. ResultsBetween January 1st 2016 and 31st December 2018, 2721 patients were treated by epilepsy nurses (2561 ambulatory controls, 8690 phone contacts). 617 patients received an intensive treatment course (six or more contacts in the observation period, range: 6–65) with an average length of 24.3 months. The average number of AED tried was 3.4. In patients with ongoing seizures (n = 310), 165 (53.2 %) reported an improvement of seizure frequency by 50 % or more. Seizure frequency fell from 4.4 to 2.4 days with seizures/months (p < 0.001). The epilepsy-related hospitalization rate was 0.86/patient; 27 episodes with status epilepticus occurred in 21 patients, three hospitalizations were due to severe side effects. There were no fatal complications. No hospitalization was related to the intensive treatment course by prescribing epilepsy nurses. The overall patients’ satisfaction was high. ConclusionIntensive epilepsy treatment facilitated by epilepsy nurses was safe and associated with high patient accept and improvement of seizure frequency.

Does spaced education improve clinical knowledge among Family Medicine residents? A cluster randomized controlled trial

Spaced education is a learning strategy to improve knowledge acquisition and retention. To date, no robust evidence exists to support the utility of spaced education in the Family Medicine residency. We aimed to test whether alerts to encourage spaced education can improve clinical knowledge as measured by scores on the Canadian Family Medicine certification examination. Method: We conducted a cluster randomized controlled trial to empirically and pragmatically test spaced education using two versions of the Family Medicine Study Guide mobile app. 12 residency training programs in Canada agreed to participate. At six intervention sites, we consented 335 of the 654 (51%) eligible residents. Residents in the intervention group were sent alerts through the app to encourage the answering of questions linked to clinical cases. At six control sites, 299 of 586 (51%) residents consented. Residents in the control group received the same app but with no alerts. Incidence rates of case completion between trial arms were compared using repeated measures analysis. We linked residents in both trial arms to their knowledge scores on the certification examination of the College of Family Physicians of Canada. Results: Over 67 weeks, there was no statistically significant difference in the completion of clinical cases by participants. The difference in mean exam scores and the associated confidence interval did not exceed the pre-defined limit of 4 percentage points. Conclusion: Further research is recommended before deploying spaced educational interventions in the Family Medicine residency to improve knowledge.

Comparison of efficacy, safety & satisfaction of intermittent versus continuous phototherapy in hyperbilirubinaemic newborns ≥35 week gestation: A randomized controlled trial.

Background & objectives:Phototherapy (PT) has become the standard of care for treating neonatal jaundice. This study was aimed to find out if intermittent PT (IPT) results in comparable rate of fall of bilirubin level to continuous PT (CPT) and results in lesser side effects and better acceptance.Methods:In this non-inferiority trial, 174 neonates ≥35 wk gestation and >2000 g with jaundice requiring PT were randomized to receive either IPT (one hour on and two hours off) or CPT (with minimum interruptions for feeding) after device stratification [light-emitting diode (LED) or compact fluorescent light (CFL)]. Bilirubin was checked 12th hourly, and calcium, vitamin D and nitric oxide (NO) levels were analyzed along with the clinical side effects and nursing and maternal satisfaction scores (CTRI Registration No. CTRI/2018/01/011072).Results:The rate of fall of bilirubin was similar in both the CPT and IPT groups [0.16 (0.10, 0.22) vs. 0.13 (0.09, 0.20) mg/dl/h, P=0.22]. The median difference with 95 per cent confidence interval of 0.03 (0.03, 0.03) mg/dl was also within the pre-defined inferiority limits. There was no significant change in the duration of PT and side effects such as fall in calcium levels, rise in vitamin D and NO levels or the clinical side effects. Maternal satisfaction favoured the IPT group, but the nurses opined that IPT was difficult to implement. Subgroup analysis for PT devices used showed that efficacy of both CFL and LED devices was equivalent.Interpretation & conclusions:IPT was non-inferior to CPT in reducing bilirubin levels in ≥35 wk neonates, irrespective of device used, and also mothers reported better satisfaction with IPT. Although IPT appears promising, CPT does not increase clinical and biochemical side effects compared to IPT.

Data-driven Probabilistic Static Security Assessment for Power System Operation Using High-order Moments

In this letter, a new formulation of Lebesgue integration is used to evaluate the probabilistic static security of power system operation with uncertain renewable energy generation. The risk of power flow solutions violating any pre-defined operation security limits is obtained by integrating a semi-algebraic set composed of polynomials. With the high-order moments of historical data of renewable energy generation, the integration is reformulated as a generalized moment problem which is then relaxed to a semi-definite program (SDP). Finally, the effectiveness of the proposed method is verified by numerical examples.

Performance-Energy Trade-off in Modern CMPs

Chip multiprocessors (CMPs) are ubiquitous in all computing systems ranging from high-end servers to mobile devices. In these systems, energy consumption is a critical design constraint as it constitutes the most significant operating cost for computing clouds. Analogous to this, longer battery life continues to be an essential user concern in mobile devices. To optimize on power consumption, modern processors are designed with Dynamic Voltage and Frequency Scaling (DVFS) support at the individual core as well as the uncore level. This allows fine-grained control of performance and energy. For an n core processor with m core and uncore frequency choices, the total DVFS configuration space is now m (n+1) (with the uncore accounting for the + 1). In addition to that, in CMPs, the performance-energy trade-off due to core/uncore frequency scaling concerning a single application cannot be determined independently as cores share critical resources like the last level cache (LLC) and the memory. Thus, unlike the uni-processor environment, the energy consumption of an application running on a CMP depends not only on its characteristics but also on those of its co-runners (applications running on other cores). The key objective of our work is to select a suitable core and uncore frequency that minimizes power consumption while limiting application performance degradation within certain pre-defined limits (can be termed as QoS requirements). The key contribution of our work is a learning-based model that is able to capture the interference due to shared cache, bus bandwidth, and memory bandwidth between applications running on multiple cores and predict near-optimal frequencies for core and uncore.

Dynamic modelling of reversible solid oxide cells for grid stabilization applications

In this work, dynamic modelling of a system based on a reversible solid oxide cell (rSOC) is developed so that it can be integrated with the grid for power balancing. The focus of this work is on the dynamic operation of a system, which is investigated using representative profiles of wind electricity production. In addition, the effect and challenges of dynamic operation on the system and stack itself are studied. Detailed operation strategies are defined during the switching process from one operational mode to another and are implemented on the dynamic process model. Simulation results show that when the rSOC system is operated in solid oxide electrolysis (SOE) and solid oxide fuel cell (SOFC) modes alternatively, energy balancing can be implemented on a continuous basis. In this process, the results show that the rSOC system operates in a safe operating range and does not deviate from the pre-defined limits. This is due to the accurate strategies developed for the switching process. It is also observed from the simulation results that the switching time is significantly influenced by the initial power of the first and the final power of the later operational mode. The proposed model of rSOC was validated using experimental data, and good agreement with experimental data was demonstrated.

A novel data-driven method for detection and localization of power system events causing violation of pre-defined ROCOF limits

For reliable operation of a power system, its situational awareness should be accurate. Similarly, for power system planning, correct post-mortem analysis of system events is required. A novel event assessment method based on the energy of system frequency and generator's rotational speed measurements has been proposed in this paper which can be used for both the real-time as well as off-line event assessment purposes. In this paper, event detection is carried out based on the magnitude of the second difference of the energy of machine's rotational speed/system frequency measurements. A detection threshold has been designed for this purpose. It successfully assesses multiple events occurring in small time interval. For event localization, a novel indicator named 'Sharpness Index' has been proposed in this paper. Performance of the proposed approach has been compared with a few existing methods and found to be more accurate and comprehensive. This proposed event assessment technique has been tested for various test cases simulated using PSS/E (Power System Simulator for Engineering) as well as real PMU (phasor measurement unit) measurements.

Integrity monitoring for Kalman filter-based localization

The problem of quantifying robot localization safety in the presence of undetected sensor faults is critical when preparing for future applications where robots may interact with humans in life-critical situations; however, the topic is only sparsely addressed in the robotics literature. In response, this work leverages prior work in aviation integrity monitoring to tackle the more challenging case of evaluating localization safety in Global Navigation Satellite System (GNSS)-denied environments. Localization integrity risk is the probability that a robot’s pose estimate lies outside pre-defined acceptable limits while no alarm is triggered. In this article, the integrity risk (i.e., localization safety) is rigorously upper bounded by accounting for both nominal sensor noise and other non-nominal sensor faults. An extended Kalman filter is employed to estimate the robot state, and a sequence of innovations is used for fault detection. The novelty of the work includes (1) the use of a time window to limit the number of monitored fault hypotheses while still guaranteeing safety with respect to previously occurring faults and (2) a new method to account for faults in the data association process.

Voltage support control strategy of grid‐connected inverter system under unbalanced grid faults to meet fault ride through requirements

Grid-connected inverter (GCI) has become the main interface for integrating modern power units, such as distributed energy resources, electric vehicles, microgrids and high voltage direct-current transmission systems. To proceed in this direction, this study presents a novel voltage support control strategy to enhance the reliability and stability of the GCI during unbalanced grid fault conditions. The proposed control strategy simultaneously achieves multiple objectives during grid faults; regulating phase voltages magnitude within pre-defined safety limits, increasing the difference between positive sequence (PS) and negative sequence (NS) voltages, eliminating both active–reactive power oscillations and the DC-link voltage oscillations. Reducing active power oscillations ensure an adjustable control for the DC-link voltage oscillations which result in third-order current harmonic component at the grid side. One of the main contributions to previous studies, reference for reactive power is computed online based on resistive–inductive grid impedance model and reference voltage sequences for the grid support. Another important contribution to existing studies is to supply both the active and reactive powers to the utility grid and load. Detailed mathematical analyses are performed to theoretically describe the behaviour of the proposed control strategy. A comprehensive set of results is presented to confirm the theoretical solutions.

A two-objective design optimisation approach for blending repairs of damaged compressor blisks

The blending of compressor blades leads to a permanent modification of the blade geometry. According to these geometric changes, the modal properties of refurbished blades will generally differ from the nominal blade design. Currently, the structural integrity of refurbished blades is maintained by only allowing blends within predefined geometric limits, where the final geometry of the blend is based on a case-by-case decision made by the technician.This work contributes to repair decisions by utilising multi-objective optimisation methods to find structurally optimised blend designs. A parameterised blending model is introduced to uniquely specify the repair design for any blade geometry. Blend designs are analysed systematically by linking the blending model with the Finite Element model of a bladed sector. The influence of the blending shape is evaluated by means of blade-alone frequencies and vibration mode shapes. A two-objective optimisation problem is derived from the frequency tuning of blended blades. The first objective results from the deviation of natural frequencies from the nominal ones, the second objective considers the proximity of natural frequencies to resonance frequencies. Moreover, the approach is applied to one bladed sector of a compressor blisk. The sensitivities of the blend geometry regarding the first six vibration modes are studied. Two damage patterns at different positions at the leading edge of the blade are chosen to exemplarily demonstrate the capability of the proposed approach. For both damage patterns, the set of Pareto optimal solutions is found using Global Pattern Search. The courses of the Pareto frontiers clearly differ and are identified to be specific for each damage pattern. Depending on the damage pattern, discontinuous as well as continuous Pareto frontiers are determined. Providing Pareto optimal solutions for repair designs, the developed approach can be understood as a valuable complement to purely experience-based design decisions.

Multi-resolution Filtering: An Empirical Method for Isolating Faint, Extended Emission in Dragonfly Data and Other Low Resolution Images

We describe an empirical, self-contained method to isolate faint, large-scale emission in imaging data of low spatial resolution. Multi-resolution filtering (MRF) uses independent data of superior spatial resolution and point source depth to create a model for all compact and high surface brightness objects in the field. This model is convolved with an appropriate kernel and subtracted from the low resolution image. The halos of bright stars are removed in a separate step and artifacts are masked. The resulting image only contains extended emission fainter than a pre-defined surface brightness limit. The method was developed for the Dragonfly Telephoto Array, which produces images that have excellent low surface brightness sensitivity but poor spatial resolution. We demonstrate the MRF technique using Dragonfly images of a satellite of the spiral galaxy M101, the tidal debris surrounding M51, two ultra-diffuse galaxies in the Coma cluster, and the galaxy NGC 5907. As part of the analysis we present a newly-identified very faint galaxy in the filtered Dragonfly image of the M101 field. We also discuss variations of the technique for cases when no low resolution data are available (self-MRF and cross-MRF). The method is implemented in mrf, an open-source MIT licensed Python package (https://github.com/AstroJacobLi/mrf).

Development of Fragility Curves for Single-Column RC Italian Bridges Using Nonlinear Static Analysis

ABSTRACT The main objective of this study is to assess the accuracy and suitability of Nonlinear Static Procedures (NSPs) in the development of analytical damage fragility curves for seismic risk assessment of large portfolios of Reinforced Concrete (RC) bridges. Seven NSP approaches, from widely used single-mode conventional pushover-based approaches to the more rigorous multi-mode conventional or adaptive pushover-based procedures are implemented. By systematically comparing fragility curve estimations in terms of shape and accuracy in predicting mean annual rates of exceeding predefined damage limit states, results indicate that when bridges can be classified as higher mode sensitive, multi-mode-based approaches offer a powerful alternative to rigorous time history analysis. In particular, Generalized Pushover Analysis and Adaptive Capacity Spectrum methods offer a better performance with respect to other multi-mode alternatives. For first mode dominated bridges, with a classical first mode shape, the performance of all methods is similar. Single-mode based procedures present an acceptable alternative only in such particular cases, for which the N2 method represents a viable approach when compared to other single-mode or multi-mode procedures.