1,925 research outputs found

    Comparison of ZigBee Replay Attacks Using a Universal Software Radio Peripheral and USB Radio

    Get PDF
    Low-Rate Wireless Personal Area Networks are a prevalent solution for communication among embedded devices. ZigBee is a leading network protocol stack based on the low-rate IEEE 802.15.4 standard that operates smart utility meters, residential and commercial building automation, and heath care networks. Such networks are essential, but low-rate, low-cost hardware is challenging to protect because end devices have tight limitations on hardware cost, memory use, and power consumption. KillerBee is a python-based framework for attacking ZigBee and other 802.15.4 networks that makes traffic eavesdropping, packet replay, and denial of service attacks straightforward to conduct. Recent works investigate software-defined radios as an even more versatile attack platform. Software defined radios can operate with greater flexibility and at greater transmit power than traditional network hardware. Software-defined radios also enable novel physical-layer attacks including reflexive jamming and synchronization header manipulation that are not possible with traditional hardware. This research implements a replay attack against a ZigBee device using a software defined radio. Replay attacks consist of an attacker recording legitimate traffic on a network and then replaying that traffic at will to cause malicious effects. Replay attacks can be very disruptive to operational systems, from turning valves in industrial controls systems to disarming door locks. Specifically, how software-defined radios can extend the effective attack range far beyond what is possible with hardware currently utilized by KillerBee is investigated. A software defined radio is tested with both directed and omnidirectional antennas and the effective attack range is compared to that of a USB radio. Tests are conducted both line-of-sight outdoors and through interior walls. The replay attack is implemented with beacon request frames

    A Comparative Evaluation of Mono-, Di- and Triglyceride of Medium Chain Fatty Acids by Lipid/Surfactant/Water Phase Diagram, Solubility Determination and Dispersion Testing for Application in Pharmaceutical Dosage Form Development

    Get PDF
    Purpose To compare physiochemical properties of mono-, diand triglycerides of medium chain fatty acids for development of oral pharmaceutical dosage forms of poorly water-soluble drugs using phase diagrams, drug solubility, and drug dispersion experiments. Methods Phase diagrams were prepared using a monoglyceride (glycerol monocaprylocaprate: Capmul MCM ® EP), a diglyceride (glycerol dicaprylate) and two triglycerides (glycerol tricaprylate

    Post-hoc derivation of SOHO Michelson doppler imager flat fields

    Get PDF
    <p><b>Context:</b> The SOHO satellite now offers a unique perspective on the Sun as it is the only space-based instrument that can provide large, high-resolution data sets over an entire 11-year solar cycle. This unique property enables detailed studies of long-term variations in the Sun. One significant problem when looking for such changes is determining what component of any variation is due to deterioration of the instrument and what is due to the Sun itself. One of the key parameters that changes over time is the apparent sensitivity of individual pixels in the CCD array. This can change considerably as a result of optics damage, radiation damage, and aging of the sensor itself. In addition to reducing the sensitivity of the telescope over time, this damage significantly changes the uniformity of the flat field of the instrument, a property that is very hard to recalibrate in space. For procedures such as feature tracking and intensity analysis, this can cause significant errors.</p> <p><b>Aims:</b> We present a method for deriving high-precision flat fields for high-resolution MDI continuum data, using analysis of existing continuum and magnetogram data sets.</p> <p><b>Methods:</b> A flat field is constructed using a large set (1000-4000 frames) of cospatial magnetogram and continuum data. The magnetogram data is used to identify and mask out magnetically active regions on the continuum data, allowing systematic biases to be avoided. This flat field can then be used to correct individual continuum images from a similar time.</p> <p><b>Results:</b> This method allows us to reduce the residual flat field error by around a factor 6-30, depending on the area considered, enough to significantly change the results from correlation-tracking analysis. One significant advantage of this method is that it can be done retrospectively using archived data, without requiring any special satellite operations.</p&gt

    Searching for primes in the digits of [pi]

    Get PDF
    Many people are fascinated by π. Vast amounts of human and computer resources have been spent producing billions of its digits. Similarly, many people are intrigued by primes. How many primes are there within the digits of π? How many can we expect to find? We present the results of some computer searches and develop a theory to predict how many of these primes extensive computer searches are likely to find

    Transplacental haemorrhage and the mode of placental delivery

    Get PDF
    A study was undertaken to determine whether the incidence and degree of transplacental haemorrhage would be affected by the following methods of placental  delivery: Brandt-Andrew's manoeuvre, spontaneous or natural delivery, and manual removal. A total of 445 patients were studied, 10-1% of whom were found to have had evidence of a clinically significant foeto-maternal haemorrhage. Except for manual removal, foeto-maternal transfer was not affected by the method of handling of the third stage

    Treatment-seeking rates in malaria endemic countries

    Get PDF
    BACKGROUND: The proportion of individuals who seek treatment for fever is an important quantity in understanding access to and use of health systems, as well as for interpreting data on disease incidence from routine surveillance systems. For many malaria endemic countries (MECs), treatment-seeking information is available from national household surveys. The aim of this paper was to assemble sub-national estimates of treatment-seeking behaviours and to predict national treatment-seeking measures for all MECs lacking household survey data. METHODS: Data on treatment seeking for fever were obtained from Demographic and Health Surveys, Malaria Indicator Surveys and Multiple Cluster Indicator Surveys for every MEC and year that data were available. National-level social, economic and health-related variables were gathered from the World Bank as putative covariates of treatment-seeking rates. A generalized additive mixed model (GAMM) was used to estimate treatment-seeking behaviours for countries where survey data were unavailable. Two separate models were developed to predict the proportion of fever cases that would seek treatment at (1) a public health facility or (2) from any kind of treatment provider. RESULTS: Treatment-seeking data were available for 74 MECs and modelled for the remaining 24. GAMMs found that the percentage of pregnant women receiving prenatal care, vaccination rates, education level, government health expenditure, and GDP growth were important predictors for both categories of treatment-seeking outcomes. Treatment-seeking rates, which varied both within and among regions, revealed that public facilities were not always the primary facility type used. CONCLUSIONS: Estimates of treatment-seeking rates show how health services are utilized and help correct reported malaria case numbers to obtain more accurate measures of disease burden. The assembled and modelled data demonstrated that while treatment-seeking rates have overall increased over time, access remains low in some malaria endemic regions and utilization of government services is in some areas limited

    Identifying factors associated with the success and failure of terrestrial insect translocations

    Get PDF
    Translocation is increasingly used as a management strategy to mitigate the effects of human activity on biodiversity. Based on the current literature, we summarised trends in terrestrial insect translocations and identified factors associated with success and failure. As the authors’ definitions of success and failure varied according to the individual sets of goals and objectives in each project, we adopted a standardised species-specific definition of success. We applied generalised linear models and information-theoretic model selection to identify the most important factors associated with translocation success. We found literature documenting the translocation of 74 terrestrial insect species to 134 release sites. Of the translocations motivated by conservation, 52% were considered successful, 31% were considered to have failed and 17% were undetermined. Our results indicate that the number of individuals released at a translocation site was the most important factor associated with translocation success, despite this being a relatively infrequent perceived cause of failure as reported by authors. Factors relating to weather and climate and habitat quality were the most commonly perceived causes of translocation failure by authors. Consideration of these factors by managers during the planning process may increase the chance of success in future translocation attempts of terrestrial insects

    Does \u27Fear of Dying\u27 Indicate a More Severe Presentation of Panic Disorder?

    Get PDF
    Research suggests a relationship between the presence of fearful cognitions and panic disorder (PD) severity. With little existing evidence addressing the clinical significance of individual panic-cognitions, the current study examined presentation and impairment differences among 331 outpatients with PD according to whether they experience “fear of dying” (FOD) during panic attacks. Patients reporting FOD (n = 153) were compared to patients denying FOD (n = 178) on variables indicating PD severity (e.g., number of symptoms) and psychiatric impairment (e.g., hospitalizations). PD patients with FOD reported a greater number of panic symptoms, agoraphobia diagnoses, and were more likely to be seeking treatment primarily for PD. We found no clinical impairment or comorbidity differences between groups. Results suggest that panic attacks with FOD are related to a more acute presentation of PD. Such results substantiate past research connecting cognitive distress and PD severity and further suggest that FOD may be particularly relevant to this relationship
    corecore