The improved faster-RCNN for spinal fracture lesions detection

Purpose: Reading spinal CT (Computed Tomography) images is very important in the diagnosis of spondylosis, which is time-consuming and prones to make biases. In this paper, we propose a framework based on Faster-RCNN to improve detection performances of three spinal fracture lesions: cfracture (cervical fracture), tfracture (thoracic fracture) and lfracture (lumbar fracture). Methods: First, we use ResNet50 to replace VGG16 in backbone network in Faster-RCNN to increase depth of training network. Second, we utilize soft-NMS (Non-Maximum Suppression) instead of NMS to avoid missed detection of overlapped lesions. Third, we simplify RPN (Region Proposal Network) to accelerate training speed and reduce missed detection. Finally, we modify the classifier layer in Faster-RCNN and choose appropriate length-width ratio by changing anchor sizes in sliding window, then adopt multi-scale strategy in training to improve efficiency and accuracy. Results: The experimental results show that the proposed scheme has a good performance, mAP (mean average precision) is 90.6%, IOU (Intersection of Union) is 88.5 and detection time is 0.053 second per CT image, which means our proposed method can accurately detect spinal fracture lesions. Conclusion: Our proposed method can provide assistance and scientific references for both doctors and patients in clinically.

Evaluation of the aerodynamic performance of the counter rotating turbo fan COBRA by means of experimental and numerical data

In the present study, steady numerical simulations performed on the counter rotating turbo fan (CRTF) COBRA are compared with experimental data carried at the CIAM C-3A test-bench in Moscow. For this purpose, a systematic analysis of the measurement uncertainties was performed for the global aerodynamic performances of the CRTF, namely, the massflow, the total pressure ratio, the isentropic efficiency, as well as the torque ratio applied on both fan rows. Several numerical models are investigated to highlight their effects on the aforementioned predicted quantities. Differences in modeling consist in grid resolutions and the use of two turbulence models popular in the turbomachinery community. To match as much as possible the experiment running conditions, the performance map of the CRTF is simulated using the exact measured speed ratio and massflow. The comparisons show good estimations of the numerical simulation over the entire performance map. The main differences between the turbulence models occur at part-speed close to stall conditions. More surprisingly at aerodynamic design point, the importance of the turbulence modeling on the predicted torque ratio has been pointed out.

Importance-performance map analysis to enhance the performance of attitude towards mobile wallet adoption among Indian consumer segments

PurposeIndia has the second highest percentage of mobile wallet adoption driven by availability of affordable smartphones and Internet. Despite a general interest, studies on its adoption have been scarce. This research assumes that user segments exist, each with their own level of maturity, and addresses the question “Are there segments which can be profiled?” Thus, the objectives of the study are to propose a model that explains the attitude of user segments towards its adoption; identify probable user segments and profile them; examine the importance and performance of constructs which influence attitude within each cluster and recommend ways to improve performance.Design/methodology/approachThis paper employs the constructs from two popular theories on technology adoption, i.e. technology acceptance model (TAM) and Unified Theory of Acceptance and Use of Technology (UTAUT). A synthesis of review of literature on these models, besides two focus group discussions (FGDs), was used to design a pilot instrument. A nationwide survey was conducted, and 744 responses were obtained. Convenience sampling was used to select the respondents. The average scores of various constructs were computed and subjected to hierarchical clustering. Further, k-means clustering was carried out. The demographic profiling of each cluster was done through cross-tabulation and differences related to attitude and intention between clusters were tracked by one-way Analysis of Variance (ANOVA). To determine the relative importance and performance of constructs within each cluster, Importance-Performance Map Analysis (IPMA) using Smart Partial Least Squares (PLS) was carried out.FindingsThe hierarchical clustering resulted in three clusters. The result of k-means clustering was used to label the clusters as Technology Enthusiasts (TE), Technology Sceptics (TS) and Technology Pragmatists (TP). The obtained clusters were found to differ in terms of perception, attitude, intention, behavior, marital status, education, occupation and income levels. With respect to each cluster, it was seen that the top three important constructs are Perceived Usefulness (PU), Security (SEC) and Lifestyle Compatibility (LC) as indicated by the IPMA. The findings indicate that mobile wallet providers should focus on all six constructs, with special focus on PU, SEC and LC. The findings of this study will help mobile wallet providers in customizing their offerings to enhance adoption attitude in all three clusters.Research limitations/implicationsThis study examines the perception of students and working professional towards mobile wallet adoption and uses this data for segmentation. However, there could be underlying differences between these two groups, as the motive behind adopting a technology may be different. Thus, treating them as homogenous user segments could be a limitation. Therefore, exploring segments and profiles for each type of user may be an area for future research. Mobile wallet providers should also give utmost importance to perceived usefulness, security and lifestyle compatibility while designing their services. This will not only enhance user trust and compatibility with mobile wallet but also improve the outcomes associated with its usage.Practical implicationsThis study will help mobile wallet providers understand the user segments and customize their service offerings.Originality/valueThis study provides a comparison of the respondent profiles of three obtained segments of mobile wallet users. While prior studies have identified segments associated with adoption of technologies like ATM banking, SMS banking, online banking, Internet banking, mobile banking etc., not much has been reported on mobile wallet adoption. To the best of the authors' knowledge, this is a novel study in India, aimed at identifying user clusters among adopters of mobile wallets and developing cluster profiles based on demographic, attitude and intention.

Resilient Safety Culture and Safety Performance: Examining the Effect in Malaysian Paramedic Training Institute through Importance-Performance Map Analysis (IPMA)

An increasing number of studies have shown that safety culture factors have a substantial influence on safety performance in a variety of industrial sectors. These factors' impact on safety performance is unclear, especially at the public service and statutory authorities. On the other hand, the understanding of indicators for safety performance in every working sector in Malaysia is on the continuing progress. Hence, this study's contribution is to explore the influence of safety culture factors (i.e., management commitment and supervision in safety, safety system) and safety competence on safety performance in government paramedic training institutes. IPMA (importance-performance map analysis) is a technique used in Smart PLS to determine the significance and performance of each of these factors. The study was conducted via an online survey and involved 258 safety and health committee members in Ministry of Health paramedic training institute. As a matter of relevance, the IPMA's empirical data study revealed that management commitment and supervision in safety were the predominant factors in determining safety performance. Meanwhile, for performance, the findings showed that worker involvement, safety system, and safety competence perform well in determining the safety performance.

Comparison of Compressor Performance Map Predictions to Test Data for a Supercritical Carbon Dioxide Brayton Power System

Supercritical carbon dioxide (sCO2) Brayton power cycles are typically designed to operate with compressor inlet conditions near the critical point to take advantage of the high density of the fluid at these conditions. While designing the cycle to operate here improves cycle efficiency, it also creates challenges for designing the compressor and predicting off-design compressor performance due to real gas fluid properties near the critical point. Multiple compressor performance map evaluation methodologies which incorporate real gas corrections have been proposed in literature with only limited evaluation of the accuracy of these methods compared to operational data from compressors designed for sCO2 power cycles. This paper evaluates compressor performance from the 100 kWe Integrated System Test (IST), which was operated at the Naval Nuclear Laboratory, over a range of compressor inlet conditions and rotational speeds relative to one real gas performance map correction methodology and assesses the impact of additional terms proposed in literature for improving the accuracy of off-design performance predictions.

The Influence of Condensation on the Performance Map of a Fuel Cell Turbocharger Turbine

Exhaust gas of an automotive fuel cell is enriched with water vapour and has a pressure potential which can be utilized by a turbine. The gas expansion in the turbine leads to droplet nucleation and condensation. This results in a release of latent heat and a decrease of the gaseous mass flow which has a considerable influence on the turbine performance. This study aims to numerically investigate the influence of these phenomena on the performance map of the radial turbine of an automotive fuel cell turbocharger. For this purpose, the classical nucleation theory and Young’s droplet growth law are integrated into an Euler-Lagrange approach. The results show an almost linear relation between the pressure ratio and the condensation while the specific aerodynamics of an operating point has only a minor influence. At 80 % relative humidity of the inflow, the investigated turbine showed condensation above a total-to-static pressure ratio of 1.8. Condensation leads to thermal throttling of the turbine and to a temperature increase of the rotor outflow of up to 50 K. Increasing humidity of the inflow increases the power output, but condensation losses reduce the efficiency.