218 research outputs found

    Integrity analysis for GPS-based navigation of UAVs in urban environment

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    The increasing use of Unmanned Aerial Vehicles (UAVs) in safety-critical missions in both civilian and military areas demands accurate and reliable navigation, where one of the key sources of navigation information is presented by Global Navigation Satellite Systems (GNSS). In challenging conditions, for example, in urban areas, the accuracy of GNSS-based navigation may degrade significantly due to user-satellite geometry and obscuration issues without being noticed by the user. Therefore, considering the essentially dynamic rate of change in this type of environment, integrity monitoring is of critical importance for understanding the level of trust we have in positioning and timing data. In this paper, the dilution of precision (DOP) coefficients under nominal and challenging conditions were investigated for the purpose of integrity monitoring in urban environments. By analyzing positioning information in a simulated urban environment using a software-based GNSS receiver, the integrity monitoring approach based on joint consideration of GNSS observables and environmental parameters has been proposed. It was shown that DOP coefficients, when considered together with a number of visible satellites and cut-off elevations specific to the urban environment carry valuable integrity information that is difficult to get using existing integrity monitoring approaches. This has allowed generating indirect integrity measures based on cut-off elevation and satellite visibility that can be used for UAV path planning and guidance in urban environments

    A machine learning based GNSS performance prediction for urban air mobility using environment recognition

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    As the primary navigation source, GNSS performance monitoring and prediction have critical importance for the success of mission-critical urban air mobility and cargo applications. In this paper, a novel machine learning based performance prediction algorithm is suggested considering environment recognition. Valid environmental parameters that support recognition and prediction stages are introduced, and K-Nearest Neighbour, Support Vector Regression and Random Forest algorithms are tested based on their prediction performance with using these environmental parameters. Performance prediction results and parameter importances are analyzed based on three types of urban environments (suburban, urban and urban-canyon) with the synthetic data generated by a high quality GNSS simulator

    Performance enhancement of low-cost INS/GNSS navigation system operating in urban environments

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    As a result of the increasing usage of UAVs (Unmanned Air Vehicles) in urban environments for UAM (Urban Air Mobility) applications, the preciseness and reliability of PNT (Positioning, Navigation and Timing) systems have critical importance for mission safety and success. With its high accuracy and global coverage, GNSS (Global Navigation Satellite System) is the primary PNT source for UAM applications. However, GNSS is highly vulnerable to Non-Line-of-Sight (NLoS) blockages and multipath (MP) reflections, which are quite common, especially in urban areas. This study proposes a machine learning-based NLoS/MP detection and exclusion algorithm using GNSS observables to enhance position estimations at the receiver level. By using the ensemble machine learning algorithm with the proposed method, overall 93.2% NLoS/MP detection accuracy was obtained, and 29.8% accuracy enhancement was achieved by excluding these detected signals

    Evaluation of prolonged pain in preterm infants with pneumothorax using heart rate variability analysis and EDIN (Échelle Douleur Inconfort Nouveau-Né, neonatal pain and discomfort scale) scores

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    Purpose The EDIN scale (Échelle Douleur Inconfort Nouveau-Né, neonatal pain and discomfort scale) and heart rate variability has been used for the evaluation of prolonged pain. The aim of our study was to assess the value of the newborn infant parasympathetic evaluation (NIPE) index and EDIN scale for the evaluation of prolonged pain in preterm infants with chest tube placement due to pneumothorax. Methods This prospective observational study assessed prolonged pain in preterm infants with a gestational age between 33 and 35 weeks undergoing installation of chest tubes. Prolonged pain was assessed using the EDIN scale and NIPE index. Results There was a significant correlation between the EDIN scale and NIPE index (r=-0.590, P=0.003). Prolonged pain is significantly more severe in the first 6 hours following chest tube installation (NIPE index: 60 [50–86] vs. 68 [45–89], P<0.002; EDIN score: 8 [7–11] vs. 6 [4–8], P<0.001). Conclusion Prolonged pain can be accurately assessed with the EDIN scale and NIPE index. However, evaluation with the EDIN scale is time-consuming. The NIPE index can provide instantaneous assessment of prolonged and continuous pain

    Global disparities in surgeons’ workloads, academic engagement and rest periods: the on-calL shIft fOr geNEral SurgeonS (LIONESS) study

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    : The workload of general surgeons is multifaceted, encompassing not only surgical procedures but also a myriad of other responsibilities. From April to May 2023, we conducted a CHERRIES-compliant internet-based survey analyzing clinical practice, academic engagement, and post-on-call rest. The questionnaire featured six sections with 35 questions. Statistical analysis used Chi-square tests, ANOVA, and logistic regression (SPSS® v. 28). The survey received a total of 1.046 responses (65.4%). Over 78.0% of responders came from Europe, 65.1% came from a general surgery unit; 92.8% of European and 87.5% of North American respondents were involved in research, compared to 71.7% in Africa. Europe led in publishing research studies (6.6 ± 8.6 yearly). Teaching involvement was high in North America (100%) and Africa (91.7%). Surgeons reported an average of 6.7 ± 4.9 on-call shifts per month, with European and North American surgeons experiencing 6.5 ± 4.9 and 7.8 ± 4.1 on-calls monthly, respectively. African surgeons had the highest on-call frequency (8.7 ± 6.1). Post-on-call, only 35.1% of respondents received a day off. Europeans were most likely (40%) to have a day off, while African surgeons were least likely (6.7%). On the adjusted multivariable analysis HDI (Human Development Index) (aOR 1.993) hospital capacity &gt; 400 beds (aOR 2.423), working in a specialty surgery unit (aOR 2.087), and making the on-call in-house (aOR 5.446), significantly predicted the likelihood of having a day off after an on-call shift. Our study revealed critical insights into the disparities in workload, access to research, and professional opportunities for surgeons across different continents, underscored by the HDI

    Geographies of a silent transition: a geographically weighted regression approach to regional fertility differences in Turkey

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    The fertility decline that Turkey has gone through in the last few decades is characterised by sharp regional inequalities, with western regions representing patterns akin to developed countries and those in the east resembling "third-world" countries, while central regions represent an in-between case. With the help of geographically weighted regression (GWR), this article is an attempt to set up a model of causal relationships that could account for the regional fertility differentials. The results indicate that the fertility decline is not a single and all-embracing process covering all regions. On the contrary, there are regions differentiated qualitatively from each other in terms of the underlying causes of the existing fertility levels

    Reflection of Medical Error Highlighted on Media in Turkey: A Retrospective Study

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    Objective: This study was performed with the aim of identifying how news on medical errors have be transmitted, and how the types, reasons, and conclusions of medical errors have been reflected to by the media in Turkey. Methods: A content analysis method was used in the study, and in this context, the data for the study was acquired by scanning five newspapers with the top editions on the national basis between the years 2012 and 2015 for the news about medical errors. Some specific selection criteria was used for the scanning of resulted news, and 116 news items acquired as a result of all the eliminations. Results: According to the results of the study; the vast majority of medical errors (40.5%) transmitted by the news resulted from the negligence of the medical staff. The medical errors were caused by physicians in the ratio of 74.1%, they most commonly occurred in state hospitals (31.9%). Another important result of the research was that medical errors resulted in either patient death to a large extent (51.7%), or permanent damage and disability to patients (25.0%). Conclusion: The news concerning medical errors provided information about the types, causes, and the results of these medical errors. It also reflected the media point of view on the issue. The examination of the content of the medical errors reported by the media were important which calls for appropriate interventions to avoid and minimize the occurrence of medical errors by improving the healthcare delivery system.PubMedWoSScopu

    Novel Approaches in Pilonidal Sinus Treatment

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    Pilonidal sinus is a very common inflammatory disease of the gluteal region. The ideal method of pilonidal sinus treatment should have a low recurrence rate with minimum excision. Moreover, the treatment method should have a short hospitalization time, should let the patient return to his normal life rapidly, should cause minimum loss of labour and should result a small scar only. In the presented review, modalities in pilonidal sinus treatment in the light of current information in the literature are evaluated

    Temporal analysis of Sand and Dust Storms (SDS) between the years 2003 and 2017 in the Central Asia

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    Mineral dust particles play a vital role in climate and the Earth's energy budget and can have impact on weather systems. It has both direct (dust-radiation effect) and indirect (dust-microphysical effect) impacts on the energy budget effect. The most important sources of dust aerosols are located in the Northern Hemisphere, primarily over the Sahara in North Africa, the Middle East, Central and South Asia respectively and Central Asia is under the influence of mineral dust. The objective of this study to carry out intensity and frequency analysis of sand and dust storm in Central Asia for the period 2003-2017 and compare the results with global values as well as the values of the Middle East region. The AOD and AE parameters can be used to differentiate between coarse and fine particles of aerosols. To investigate average annual and monthly AOD (aerosol optical depth) and AE (angstrom exponent) for the period 2003-2017, AOD and AE data of MODIS Aqua is obtained from Giovanni website. In summary, for the last years (2013-2017), annual mean AOD is comparably lower than the other periods while the values are the highest between 2008 and 2012 for both Central Asia and Middle East. The results point out that there is no increasing trend in AOD values for the recent years and annual Central Asia AOD values show a similar trend with the Middle East AOD values

    The Effect of Loneliness at Work and Work Stress on Work Alienation and Work Alienation on Performance among Health Employees

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    This study aims to determine the effect of loneliness at work and work stress on work alienation and work alienation on employee performance among employees in Turkish healthcare institutions. Data collection tools were composed of Loneliness at Work Scale Work Stress Scale, Work Alienation Scale and Performance Scale. The study results revealed that work alienation was influenced by work stress (ρ=0.689) and loneliness at work (ρ=0.433) positively. These influences were statistically significant (p<0.05). In addition, it was found that work alienation had a negative and statistically significant effect on performance (ρ=-0.264) (p<0.05). The performance of health employees decreased with increasing work alienation. It should be noted that low job performance of these employee may lead to irreversible consequences such as death or disability. Viewed from this perspective, the determined factors that cause work alienation in employees (health institutions) play significant role and health institutions are required to take precautionary measures
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