1,872 research outputs found
How much variation in oocyte yield after controlled ovarian stimulation can be explained? A multilevel modelling study
No full textStudy question: How much variation in COS response can be accounted for by known patient and treatment characteristics, and what are the implications for individualised stimulation protocols?Summary answer: There is substantial variation in the COS responses of similar women and in repeated COS episodes undertaken by the same woman, which cannot be accounted for at present. This suggests that there is likely to be limited scope for personalised treatment unless additional predictors of ovarian response can be identified.What is known already: The goal of individualized COS is to safely collect enough oocytes to maximise the chance of success in an ART cycle. Personalisation of treatment rests on the ability to reduce variation in response through modifiable factors. Study design, size, duration: Multilevel modelling of a routine ART database covering the period 1st October 2008 to 8th August 2012 was employed to estimate the amount of variation in COS response and the extent to which this could be explained by immutable patient characteristics and by manipulable treatment variables. 1851 treatment cycles undertaken by 1430 patients were included. The study was not subject to attrition, as cancelled cycles were included in the analysis.Participants/materials, setting, methods: Women of 21-43 years of age undergoing ovarian stimulation for IVF (possibly with ICSI) using their own eggs at the Reproductive Medicine Department of St Mary’s Hospital, Manchester, England.Main results and the role of chance: Substantial unexplained variation in COS response was observed (3.4-fold (95% CI: 3.12 to 3.61)). Only a relatively small amount of this variation (around 19%) can be explained by modifiable factors. A significant, previously undescribed predictor of response was the practitioner performing oocyte pickup, with 1.5 fold variation between surgeons with the highest and lowest yields. Limitations, reasons for caution: Although a large number of covariables were adjusted for in the analysis, including those that were used for dosing and determination of the stimulation regimen, this study is subject to confounding due to unmeasured variables and measurement error. Wider implications of the findings: The present study suggests that there are limits to the extent that COS response can be predicted on the basis of known factors, or controlled by manipulation of treatment factors. Moreover, modifiable variation in response appears to be partially attributable to differences between surgeons performing oocyte pick up. Consequently, consistent prevention of ineffective or unsafe responses is not likely to be possible at present. Our results highlight the importance of blinding surgeons in RCTs. Study funding/ competing interests: JW is funded by a Doctoral Research Fellowship from the National Institute for Health Research (DRF-2014-07-050) supervised by SAR. The views expressed in this publication are those of the authors and not necessarily those of the NHS, the National Institute for Health Research or the Department of Health. JW is a statistical editor of the Cochrane Gynaecology and Fertility Group. SR is a statistical editor for Human Reproduction. JW also declares that publishing peer-reviewed articles benefits his career. ALM has received consultation fees fromfrom MSD, Merck Serono, Ferring, TEVA, Roche, Beckman Coulter.<br/
Detecting Single-antenna Spoofing Attacks by Correlation in Time Series of Raw Measurements
No full textGlobal Navigation Satellite System (GNSS) receivers are vulnerable to intentional radio frequency interferences, posing significant risks to their performance and reliability. Among these threats, it has been widely argued that modern GNSS-equipped AndroidTM smartphones are resilient to non-coherent spoofing attacks. This study challenges such a perception by highlighting the vulnerability of GNSS-equipped AndroidTM smartphones to single-antenna, non-coherent spoofing attacks and proposing a novel, application-level detection technique solely based on raw GNSS observables, i.e., carrier-to-noise-density time series. The analysis demonstrated the capability of successfully detecting such attacks by observing the cross-correlation among Global Navigation Satellite System (GNSS) measurements time series. Cross-correlation quantified by Pearson’s correlation coefficients shows a relevant increment during harmful spoofing attacks. Under these conditions, the proposed methodology allows to rise a spoofing alarm in about 5 seconds with a false alarm probability of 1.5%. Furthermore, the proposed technique does not require low-level signal access, making it suitable for implementation at the application layer in a large number of smart devices with limited knowledge of their low-level system architecture. A validation campaign has been performed by testing 18 different AndroidTM devices and chipsets, thus demonstrating the applicability of the proposed method independently from the device under test
Improving GNSS Spoofing Awareness in Smartphones via Statistical Processing of Raw Measurements
No full textDue to the low received power of Global Navigation Satellite Signals (GNSS), the performance of GNSS receivers can be disrupted by anthropogenic radio frequency interferences, with intentional jamming and spoofing activities being among the most critical threats. It is reported in the literature that modern, GNSS-equipped Android smartphones are generally resistant to simplistic spoofing, and many recent contributions support such a biased belief. In this paper, we present the results of a test campaign designed to further stress the resilience of such devices to simplistic spoofing attacks and highlight their actual vulnerability. We then propose an effective spoofing detection technique, that exploits the spatial and temporal correlation of the counterfeit signals by leveraging the statistical analysis of raw GNSS measurements. By not requiring access to the low signal processing level of the GNSS receiver, the proposed solution applies to any device embedding a GNSS receiver that provides raw GNSS measurements, such as current Android smartphones. Vulnerability analysis and validation of the proposed technique were conducted in a controlled environment by transmitting realistic, counterfeit Global Positioning System L1/CA navigation signals to a variety of Android smartphones embedding also different GNSS chipsets. We show that, under proper conditions, the devices were vulnerable to the attacks and that the effects were visible through their raw measurements, i.e., Carrier-to-noise ratio , pseudo-range measurements, and position estimates. In particular, the study demonstrates that cross-correlation between the time series provided by each device for different GNSS satellites increases under spoofing conditions, thus constituting an effective metric to detect the attack within a few seconds
Integration methods of a vehicles emergency response system based on navigational units
No full textStudying the state of the art of current integration methods of a car engine with the automobile mechatronic system by using neural networks to orchestrate the methods of integration of a car engine with the automobile mechatronic system by using algorithmic electronic control based on new neural networks; to formulate the methodology of electronic model control of an engine with a mechatronic adapter; to design a model enabling calculation of input-output data; to analyze results of cold and hot tests of an engine, develop methods improving tests with the help of mechatronic adapter; to reason power and torque of an engine integrated with the mechatronic adapter; conceptualize the method of assessing fuel economy and environmental performances of an engine; put forward a guidance on research application and estimate economic efficiency. The article discusses the topic of improving the safety of transportation by introducing the latest capabilities of advanced technologies. The proposed solution uses the composition of engineering networks to expand such networks as ERA-GLONASS and e Call, which allows not only to transmit additional information, but also to combine information to determine the necessary means of emergency assistance and coordinate the entire emergency response operation. The key concept of the approach is to model the cyber-physical components of the human device using collections of resources that reflect them. Services have the ability to self-regulate, which allows them to independently adapt their behavior to the context of the vehicle driver's environment
On multi-block lattice Boltzmann method for high Knudsen number flows
No full textThis work introduces a new computational framework aimed at advancing the modeling of gas transport in confined porous media, particularly shale and tight geological formations that are characterized by their intricate network of meso- and micro-scale fractures and a broad distribution of organic pores. Accurate simulation of gas behavior in such media is challenging due to the complex interactions occurring at high Knudsen numbers, where conventional continuum-based methods fail and kinetic-theory approach becomes more suitable. To tackle these complexities, this work presents a lattice Boltzmann framework tailored for large computational domains with multi-scale pore structures from nano to micro scales. This framework incorporates slip boundary conditions and features an innovative multi-block approach to enable efficient simulations over a wide range of pore sizes, from nanometers to micrometers. The novel contributions of this work include: A scale-informed grid refinement strategy, the incorporation of shear stress terms, multi-block evolution algorithm, and a novel classification method for implementing specular reflection boundary conditions on irregular surfaces. Validation against Direct Simulation Monte Carlo and Molecular Dynamics data from the literature confirms the model’s accuracy in predicting gas behavior. Simulations of methane transport in tight porous media with irregular geometries highlight the framework’s effectiveness in modeling gas permeability across varying pressure conditions. Apparent permeability results across a range of Knudsen numbers demonstrate the versatility of this framework in capturing the physics of gas transport in confined porous media.Document Type: Original articleCited as: Rustamov, N., Mostaghimi, P., Aryana, S. A. On multi-block lattice Boltzmann method for high Knudsen number flows. Advances in Geo-Energy Research, 2025, 16(2): 143-157. https://doi.org/10.46690/ager.2025.05.0
Исследование влияния парамeтров поездопотоков на показатели работы сортировочной станции методами имитационного моделирования
No full textG. Mozolevych: ORCID 0000-0002-4715-1645; R. Rustamov: ORCID 0000-0002-5860-1840EN: The structure of the functional simulation model of sorting station realized as a software product. Results of research of influence of parameters of train flows on the performance of the sorting station, made its use. Special attention was paid to the influence of the parameters of the train flows on the efficiency of the process of train making.UK: Приведена структура функціональної імітаційної моделі сортувальної станції, реалізованої в якості програмного продукту. Приведені результати дослідження впливу параметрів поїздопотоків на показники роботи сортувальної станції, виконаного з її використанням. Особливу увагу було приділено впливу параметрів поїздопотокв на ефективність процесу составоутворення.RU: Приведена структура функциональной имитационной модели сортировочной станции, реализованной в качестве программного продукта. Приведены результаты исследования влияния параметров поездопотоков на показатели работы сортировочной станции, выполненного с её использованием. Особое внимание было уделено влиянию параметров поездопотоков на эффективность процесса составообразования
Assessment of the Vulnerability to Spoofing Attacks of GNSS Receivers Integrated in Consumer Devices
No full textIn this paper, we investigate the effects of spoofing attacks on the mass-market positioning and navigation units
integrated in modern day AndroidTM smartphones. In order to operate spoofing in a real environment, we signed and implemented a portable, configurable, low-cost GPS spoofer exploiting a software-defined radio (SDR) implementation and a low-cost front-end. Such a tool has been exploited to set up a test campaign trying to mislead the Position, Velocity and Time computation of different AndroidTM smartphones. The effects of such simplistic spoofing attack on the smartphone GNSS has been assessed observing raw measurements and the evaluated positions and time. The main findings of this work showed that modern AndroidTM devices have a remarkable resilience to simplistic spoofing attacks, highlighting in parallel further potential weaknesses to be protected by means of practical defence mechanisms and countermeasures to spoofing
GNSS Anti-Spoofing Defense Based on Cooperative Positioning
No full textRadio navigation is of utmost importance in several application fields. Nowadays, many civil and professional applications massively rely on the Global Navigation Satellite System (GNSS) and related technologies to accurately estimate position and time. Existing GNSS-based systems are threatened by malicious attacks among which spoofing and meaconing constitute severe challenges to the receiver. Several of such GNSS systems constitute mass market applications and devices, and a threat to the GNSS receiver could have cascading effects at application levels and for interconnected systems. Networked GNSS receivers are in general ubiquitous because any receiver embedded in a complex system such as a smart device or smart connected cars can exploit network connectivity. This novel generation of valuable-performance GNSS receivers are prone both to standard RF spoofing attacks and to cyber-attacks conceived to hijack complex network based services such as DGNSS-based cooperative positioning. By means of a set of experimental tests, this paper highlights possible metrics to be checked to identify malicious attacks to the positioning and navigation systems in mass market connected devices. The network-based exchange of GNSS data such as GNSS raw measurements recently disclosed in Android smart devices is conceived in this work to offer the possibility to compare or combine such metrics to better identifies spoofing and meaconing attacks
Scenario of Linguo – Cultural Essence of Verbs Expressing Behavior Peculiar to the Uzbeks
No full textThe author analyses lingua-cognitive and linguo-cultural essence of the verbs compiling the scenario of spiritual processes peculiar to the conduct of the Uzbeks. Here, the verbs compiling this scenario, based on systematic peculiarities in paradigmatic relations, go into syntagmatic relations, in expressing the very reality. The author also says that this condition creates instantaneous condition and this condition put them in order of a new system. In this order, the basis of verbs is stable lingua-cultural value. The author tries to prove that some verbs serve as direct unifiers of the events of a literary work
IBN SINO FALSAFIY QARASHLARINI O‘RGANILISH TARIXIDAN
No full textВ статье говорится о философских взглядах в творчестве Ибн Сины и истории их изучения. Автор Ибн Сина пытался осветить философскую суть своих произведений, написанных в области философии, природы, медицины и художественной литературы, а также музыки.The article talks about the philosophical views in the works of Ibn Sina and the history of their study. The author Ibn Sina tried to illuminate the philosophical essence of his works written in the fields of philosophy, nature, medicine and fiction, as well as music.Maqolada Ibn Sino ijodida falsafiy qarashlar va ularning o‘rganilish tarixi haqida so‘z borgan. Muallif Ibn Sino falsafa, tabiat, tibbiyot va badiiy adabiyotda, musiqa kabi boshqa fanlar sohasida yozgan asarlarini falsafiy mohiyatini yoritishga harakat qilgan
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