TO LOCALISE OR TO BE LOCALISED WITH WIFI IN THE HUBEI MUSEUM?

ISPRS The first method detects the beacon frames send by smartphones, laptops and other WiFi enabled devices in range using Libelium Meshlium Xtreme monitors. Their MAC addresses and the signal strength is measured by the Meshlium Xtreme and stored on an external database. We call this method WiFi monitoring. The second method a Wifi enabled device, like a smartphone, measures the signal strength of multiple Wifi Access Points in range to localise itself based on a previously created radio map. This method is known as WiFi fingerprinting. Both methods have some advantages and disadvantages. Advantages of the common way of WiFi fingerprinting are that the implementation costs are relatively low, because it is usually possible to use (a part of) the existing WiFi AP infrastructure. WiFi fingerprinting can reach a relatively high accuracy in the order of magnitude of meters. Finally, the location granularity can be adjusted to what is necessary for the purpose of the indoor localisation. This makes it employable for a wide range of purposes. The question remains how suitable these methods are for a 3D indoor navigation system for the Hubei provincial museum. One important aspect is the localisation-granularity necessary for the application. In a museum it is not necessary to know the exact X,Y position of a user (such high accuracy is unnecessary), more important is to know in which room the user is located so the information on exhibitions can be presented and the starting point of the navigation can be determined. Both methods can track the user and tell the room he or she is located at. Although WiFi smartphone monitoring may have a low update frequency it is still suitable for a navigation system for a museum since visitors usually spend more than a couple of minutes within a room

Μέτρηση και αξιολόγηση ατμοσφαιρικής ρύπανσης σε αστικό περιβάλλον

131 σ.Η παρούσα διπλωματική εργασία εστιάζει σε ένα σημαντικό περιβαλλοντικό πρόβλημα, την ατμοσφαιρική ρύπανση. Η υποβάθμιση της ποιότητας του ατμοσφαιρικού αέρα τα τελευταία χρόνια απασχολεί ιδιαίτερα την πολιτεία λόγω της σημαντικότητας του στην ποιότητα της ανθρώπινης ζωής, τη δημόσια υγεία και το περιβάλλον. Στην παρούσα μελέτη επιδιώκεται με την διενέργεια μετρήσεων των συγκεντρώσεων των ατμοσφαιρικών ρύπων που διεξάγεται από ειδικό σταθμό καταγραφής να δοθεί μία εικόνα της κατάστασης του προβλήματος σε μια ιδιαίτερα πυκνοκατοικημένη περιοχή στο κέντρο της Αθήνας.This thesis focuses on the crucial environmental problem of air pollution. Nowadays, the degradation of air quality highly concerns the state, because of its importance in human life, health and environment. The aim of this study is to give a picture of this problem, in a highly populated area in the center of Athens, through measurements of air pollutants concentrations gathered from a special recording station.Αντιγόνη Α. Μακρ

Coagulase-negative staphylococcal bloodstream and prosthetic-device-associated infections: the role of biofilm formation and distribution of adhesin and toxin genes

Coagulase-negative staphylococci (CNS), especially Staphylococcus epidermidis and Staphylococcus haemolyticus, have emerged as opportunistic pathogens in immunocompromised patients and those with indwelling medical devices. In this study, CNS recovered from patients with bloodstream infections (BSIs) or prosthetic-device-associated infections (PDAls) were compared in terms of biofilm formation, antimicrobial resistance, clonal distribution, and carriage of adhesin and toxin genes. A total of 226 CNS isolates (168 S. epidermidis and 58 S. haemolyticus) recovered from hospital inpatients with BSIs (100 isolates) or PDAls (126 isolates) were tested for biofilm formation, antimicrobial susceptibility, and mecA, ica operon, adhesin (aap, bap, fnbA, atlE, fbe) and toxin (tst, sea, sec) genes. The selected CNS were classified into pulsotypes by PFGE and assigned to sequence types by multilocus sequence typing. In total, 106/226 isolates (46.9%) produced biofilm, whereas 150 (66.4 %) carried the ica operon. Most isolates carried mecA and were multidrug resistant (90.7 %). CNS recovered from BSIs were significantly more likely to produce biofilm (P=0.003), be resistant to antimicrobials and carry mecA (P0.05). Although PFGE revealed genetic diversity, especially among S. epidermidis, analysis of representative strains from the main PFGE types by multilocus sequence typing revealed three major clones (ST2, ST5 and ST16). A clonal relationship was found with respect to antimicrobial susceptibility and ica and aap gene carriage, reinforcing the premise of clonal expansion in hospital settings. The results of this study suggest that the pathogenesis of BSIs is associated with biofilm formation and high-level antimicrobial resistance, whereas PDAls are related to the adhesion capabilities of S. epidermidis and S. haemolyticus strains