Adaptive indoor positioning model based on WLAN-fingerprinting for dynamic and multi-floor environments

The Global Positioning System demonstrates the significance of Location Based Services but it cannot be used indoors due to the lack of line of sight between satellites and receivers. Indoor Positioning Systems are needed to provide indoor Location Based Services. Wireless LAN fingerprints are one of the best choices for Indoor Positioning Systems because of their low cost, and high accuracy, however they have many drawbacks: creating radio maps is time consuming, the radio maps will become outdated with any environmental change, different mobile devices read the received signal strength (RSS) differently, and peoples’ presence in LOS between access points and mobile device affects the RSS. This research proposes a new Adaptive Indoor Positioning System model (called DIPS) based on: a dynamic radio map generator, RSS certainty technique and peoples’ presence effect integration for dynamic and multi-floor environments. Dynamic in our context refers to the effects of people and device heterogeneity. DIPS can achieve 98% and 92% positioning accuracy for floor and room positioning, and it achieves 1.2 m for point positioning error. RSS certainty enhanced the positioning accuracy for floor and room for different mobile devices by 11% and 9%. Then by considering the peoples’ presence effect, the error is reduced by 0.2 m. In comparison with other works, DIPS achieves better positioning without extra devices

Measurement of tibial nerve excursion during ankle joint dorsiflexion in a weight-bearing position with ultrasound imaging

The ability of peripheral nerves to stretch and slide is thought to be of paramount importance to maintain ideal neural function. Excursion in peripheral nerves such as the tibial can be measured by analysis of ultrasound images. The aim of this study was to assess the degree of longitudinal tibial nerve excursion as the ankle moved from plantar flexion to dorsiflexion in a standardised weight-bearing position. The reliability of ultrasound imaging to measure tibial nerve excursion was also quantified

Shisha smokers’ determinants of use, knowledge and perception towards shisha (waterpipe) smoking in Penang, Malaysia

Background: Tobacco smoking is a serious health problem worldwide. Malaysia as many of south Asian countries faces the challenge of rising tobacco consumption. Despite the apparent spread of Shisha smoking phenomenon among Malaysian population, little is known about the safety concerns and determinants of Shisha smokers in this community. Objectives: This study aimed to determine the social determinants of Shisha smoking among Malaysian population in Penang Island, Malaysia and to explore their health related knowledge and perception toward Shisha smoking. Methods: The survey was conducted using simple random sampling by randomly distributing self-administered questionnaires to consumers in Shisha lounges located in Penang Island. Statistical analyses were performed using the Statistical Package for Social Science (SPSS) version 20. Results: A total number of 171 (42.75%) of respondents participated in this study. Mean age was 21.5±4.4 years. The majority were male, Malay (79.6%, 63.1% respectively). About 97.1% of respondents smoke Shisha either alone or with tobacco cigarettes. The majority (63.1%) started Shisha smoking at an age ≤ 20 years old, always in a café' (72.2%), share Shisha smoking with others (81.6%). Only 35.9% of respondents reported smoking Shisha daily. 71% reported smoking ≤ 7 bowls per week. 50.5% claimed smoking Shisha for more than 60 minutes per session. Boredom, outing and meeting with friends and family ranked first among the motives for smoking Shisha. Regarding knowledge about Shisha smoking, the majority believes that cigarettes are more harmful, more addictive and has more nicotine than waterpipe (60.2%, 71.8% and 67%; respectively). A large proportion (66%) of respondents believes that Shisha smoking doesn't transmit hepatitis infection. The majority of respondents perceived Shisha smoking acceptable by society and parents, compared to cigarettes (67% and 60.2%; respectively). The vast majority of respondents believe that Shisha smoking relieves stress and tension (77.7%), while the minority believes that Shisha smokers have more friends than non-smokers. Regarding access to Shisha, half of respondents agreed that Shisha is easily accessible than cigarettes. The majority of respondent foresees increasing popularity of Shisha smoking in the next 5 years (83.5%). Conclusion: This study showed that there is a high prevalence of Shisha smoking among the Malaysian youth associated with false believes about its health effects. Further studies involving larger population are encouraged

Color stability of nanohybrid and microhybrid composites after immersion in common coloring beverages at different times: a laboratory study

Abstract Objective/Aim This in vitro study aimed to evaluate the color stability of microhybrid and nanohybrid restorative composites after exposure to immersion media common in Yemen for different periods. Materials and methods Two composite materials, nanohybrid Tetric N-Ceram and microhybrid Te-Econom Plus, were investigated. Six groups of 30 cylindrical specimens (n = 5/group; diameter, 10 mm; thickness, 2 mm; shade A2) of each restorative material were immersed for 1 week in distilled water, qat solution, Yemeni coffee, traditional Yemeni coffee (qishr), red tea, and Dilsi cola. Color changes were evaluated by colorimetry. The color data and pH were measured before and 1, 3, and 7 days after immersion. The data were statistically analyzed. Results Tetric N-Ceram showed lesser discoloration than did Te-Econom Plus. Qat, coffee, and red tea caused highly significant discoloration than did Dilsi cola and distilled water (p < 0.05). The role of low pH in discoloration depended on the colorant. Discussion Nanohybrid Tetric N-Ceram composites are more resistant to discoloration than are microhybrid Te-Econom Plus composites. Qat and coffee have the highest effect on composite discoloration. Conclusions These findings will aid in selecting composite materials and patient instruction