Improving an Open Source Geocoding Server

A common problem in geocoding is that the postal addresses as requested by the user differ from the addresses as described in the database. The online, open source geocoder called Nominatim is one of the most used geocoders nowadays. However, this geocoder lacks the interactivity that most of the online geocoders already offer. The Nominatim geocoder provides no feedback to the user while typing addresses. Also, the geocoder cannot deal with any misspelling errors introduced by the user in the requested address. This thesis is about extending the functionality of the Nominatim geocoder to provide fuzzy search and autocomplete features. In this work I propose a new index and search strategy for the OpenStreetMap reference dataset. Also, I extend the search algorithm to geocode new address types such as street intersections. Both the original Nominatim geocoder and the proposed solution are compared using metrics such as the precision of the results, match rate and keystrokes saved by the autocomplete feature. The test addresses used in this work are a subset selected among the Swedish addresses available in the OpenStreetMap data set. The results show that the proposed geocoder performs better when compared to the original Nominatim geocoder. In the proposed geocoder, the users get address suggestions as they type, adding interactivity to the original geocoder. Also, the proposed geocoder is able to find the right address in the presence of errors in the user query with a match rate of 98%.The demand of geospatial information is increasing during the last years. There are more and more mobile applications and services that require from the users to enter some information about where they are, or the address of the place they want to find for example. The systems that convert postal addresses or place descriptions into coordinates are called geocoders. How good or bad a geocoder is not only depends on the information the geocoder contains, but also on how easy is for the users to find the desired addresses. There are many well-known web sites that we use in our everyday life to find the location of an address. For example sites like Google Maps, Bing Maps or Yahoo Maps are accessed by millions of users every day to use such services. Among the main features of the mentioned geocoders are the ability to predict the address the user is writing in the search box, and sometimes even to correct any misspellings introduced by the user. To make it more complicated, the predictions and error corrections these systems perform are done in real time. The owners of these address search engines usually impose some restrictions on the number of addresses a user is allowed to search monthly, above which the user needs to pay a fee in order to keep using the system. This limit is usually high enough for the end user, but it might not be enough for the software developers that want to use geospatial data in their products. There is a free alternative to the address search engines mentioned above called Nominatim. Nominatim is an open source project whose purpose is to search addresses among the OpenStreetMap dataset. OpenStreetMap is a collaborative project that tries to map places in the real world into coordinates. The main drawback of Nominatim is that the usability is not as good as the competitors. Nominatim is unable to find addresses that are not correctly spelled, neither predicts the user needs. In order for this address search engine to be among the most used the prediction and error correction features need to be added. In this thesis work I extend the search algorithms of Nominatim to add the functionality mentioned above. The address search engine proposed in this thesis offers a free and open source alternative to users and systems that require access to geospatial data without restrictions

Influence of the pavement surface on the vibrations induced by heavy traffic in road bridges

The irregularity of the pavement surface governs the traffic-induced vibrations in road bridges, but it is either ignored or simulated by means of ideal pavements that differ significantly from real cases. This work presents a detailed dynamic analysis of a heavy truck crossing a 40-m span composite deck bridge using on-site measurements of different existing road profiles, as well as code-based ideal pavements. By activating or deactivating certain spatial frequency bands of the pavement, it is observed that the ranges 0.2 - 1 and 0.02 - 0.2 cycles/m are critical for the comfort of the pedestrians and the vehicle users, respectively. Well maintained roads with low values of the displacement Power Spectral Density (PSD) associated with these spatial frequency ranges could reduce significantly the vibration on the sidewalks and, specially, in the vehicle cabin. Finally, a consistent road categorisation for vibration assessment based on the PSD of the pavement irregularity evaluated at the dominant frequencies is proposed

Reversing factor Xa inhibitors - clinical utility of andexanet alfa

Approximately half of patients started on an oral anticoagulant in the USA now receive one of the newer direct oral anticoagulants (DOACs). Although there is an approved reversal agent for the direct thrombin inhibitor dabigatran, a specific reversal agent for the anti-factor Xa (FXa) DOACs has yet to be licensed. Unlike the strategy to reverse the only oral direct thrombin inhibitor with idarucizumab, which is a humanized monoclonal antibody fragment, a different approach is necessary to design a single agent that can reverse multiple anti-FXa medications. Andexanet alfa is a FXa decoy designed to reverse all anticoagulants that act through this part of the coagulation cascade including anti-FXa DOACs, such as apixaban, edoxaban and rivaroxaban, and indirect FXa inhibitors such as low-molecular-weight heparins. This narrative reviews the development of andexanet alfa and explores its basic science, pharmacokinetics/pharmacodynamics, animal models, and human studies

Trends in Venous Thromboembolism Anticoagulation in Patients Hospitalized With COVID-19

Importance: Venous thromboembolism (VTE) is a common complication of COVID-19. It is not well understood how hospitals have managed VTE prevention and the effect of prevention strategies on mortality. Objective: To characterize frequency, variation across hospitals, and change over time in VTE prophylaxis and treatment-dose anticoagulation in patients hospitalized for COVID-19, as well as the association of anticoagulation strategies with in-hospital and 60-day mortality. Design, Setting, and Participants: This cohort study of adults hospitalized with COVID-19 used a pseudorandom sample from 30 US hospitals in the state of Michigan participating in a collaborative quality initiative. Data analyzed were from patients hospitalized between March 7, 2020, and June 17, 2020. Data were analyzed through March 2021. Exposures: Nonadherence to VTE prophylaxis (defined as missing ≥2 days of VTE prophylaxis) and receipt of treatment-dose or prophylactic-dose anticoagulants vs no anticoagulation during hospitalization. Main Outcomes and Measures: The effect of nonadherence and anticoagulation strategies on in-hospital and 60-day mortality was assessed using multinomial logit models with inverse probability of treatment weighting. Results: Of a total 1351 patients with COVID-19 included (median [IQR] age, 64 [52-75] years; 47.7% women, 48.9% Black patients), only 18 (1.3%) had a confirmed VTE, and 219 (16.2%) received treatment-dose anticoagulation. Use of treatment-dose anticoagulation without imaging ranged from 0% to 29% across hospitals and increased over time (adjusted odds ratio [aOR], 1.46; 95% CI, 1.31-1.61 per week). Of 1127 patients who ever received anticoagulation, 392 (34.8%) missed 2 or more days of prophylaxis. Missed prophylaxis varied from 11% to 61% across hospitals and decreased markedly over time (aOR, 0.89; 95% CI, 0.82-0.97 per week). VTE nonadherence was associated with higher 60-day (adjusted hazard ratio [aHR], 1.31; 95% CI, 1.03-1.67) but not in-hospital mortality (aHR, 0.97; 95% CI, 0.91-1.03). Receiving any dose of anticoagulation (vs no anticoagulation) was associated with lower in-hospital mortality (only prophylactic dose: aHR, 0.36; 95% CI, 0.26-0.52; any treatment dose: aHR, 0.38; 95% CI, 0.25-0.58). However, only the prophylactic dose of anticoagulation remained associated with lower mortality at 60 days (prophylactic dose: aHR, 0.71; 95% CI, 0.51-0.90; treatment dose: aHR, 0.92; 95% CI, 0.63-1.35). Conclusions and Relevance: This large, multicenter cohort of patients hospitalized with COVID-19, found evidence of rapid dissemination and implementation of anticoagulation strategies, including use of treatment-dose anticoagulation. As only prophylactic-dose anticoagulation was associated with lower 60-day mortality, prophylactic dosing strategies may be optimal for patients hospitalized with COVID-19

Tire/road noise, texture, and vertical accelerations: Surface assessment of an urban road

Pavements are made up of several layers with different mechanical and functional characteristics. The correct design of the surface layerof a roadmay leadto pavements with bettercharacteristics regarding ride qualityand safety, but also pavements that may be used as a measure against noise.The use oflow-noise pavements maybe aneffective measure to reduce the generation of acoustic pollutionby roadtraffic.This work aims to assesssome functionalcharacteristicsof a rehabilitated urban street,after two months in service conditions.The pavement was fabricated with a gap-graded bituminous mixture type Stone Mastic Asphalt(SMA) with crumb rubber(CR)from end-of-life (EOL) tires.This work studies the acoustic performance of the pavement, as well as other surface characteristics such as the macrotexturedepth(MPD)and the unevenness(IRI), establishing the relationship between them and the tire/road noise at different frequencies.Finally, the mainvertical acceleration frequencies of the pavement/vehiclesystemat 50 km/h were also assessedand related to the pavement unevennessand conservation.According to the results, this mixture might be used as a noise mitigation measure within the Action Plans of some urban areas with problems related to noise. The macrotexturedepthofthe mixture contributes to its acoustic performance at low frequencies;however, its acoustic performance cannot be totally explained from a macrotexture point of vie