Two-Time Procedure for Calculation of Carrier Frequency of Phasomodulated in Communication Systems

The use in radio communication systems of phase modulation of a signal intended for the transmission of useful information in a continuous mode creates the problem of frequency uncertainty of the received signal by frequency.In practice, it is not possible to implement frequency estimation in the conditions of chat uncertainty of the signal in the channel with low energy of the signal received in the continuous mode. Therefore, the estimation of the carrier frequency offset of the signal received relative to the nominal value is carried out before other synchronization procedures are included, namely: phase synchronization and clock synchronization. The paper generalizes the procedure and forms a two-step procedure for calculating the carrier frequency of the phase-modulated signal of a radio communication system for data transmission in a continuous mode, taking into account the condition of uncertainty of all signal parameters. Achieving the minimum observation interval in the given order of calculation of the carrier frequency is ensured by the use of the fast Fourier transform function. In order to analyze the effectiveness of this procedure, the process of estimating the carrier frequency of the phase-modulated signal of the radio communication system during data transmission in continuous mode and functional dependences of the maximum frequency in the signal spectrum and the minimum variance of carrier frequency estimation. This procedure allows a two-stage assessment of the carrier frequency according to the rule of maximum likelihood, taking into account the condition of uncertainty of all parameters of the signal received by the satellite communication system in a continuous mode with a minimum observation interval. Achieving the minimum observation interval in the given order of carrier frequency estimation is ensured by using the fast Fourier transform function and two estimation steps. The analysis of the efficiency of the estimation of the specified order was carried out on the basis of comparison of a ratio of the received minimum variance of an estimation of a carrier frequency and theoretically possible border of the minimum variance.

Development of a method for differential analysis of data on the arterial blood oxygenation in healthy adults

Monitoring of arterial blood saturation with oxygen (oxygenation) has gained special significance as a result of the COVID-19 pandemic. A new method for computer processing of saturation records (so-called SaO2 signals), based on the study of differentials (increments) from signals, was proposed. Finding a differential for a time series involves calculating the difference between the pairs of its adjacent elements. The differential is non-zero only if the elements in a pair are different. The study of differentials together with primary signals for a set of records (20 subjects) shows that the spectrum of observed levels of blood saturation is discrete and limited (from 2 to 10 levels). In addition, changes in saturation levels (switches) occur only between the nearest levels. New indicators of the variability of blood saturation were proposed. These are the frequencies of saturation level switches (event intensities) and the intervals between them. It was established that these indicators are described by statistical distributions of Poisson and Erlang, respectively. Comparison of new variability indicators with the most reliable statistical – inter-quartile range – indicates that the new indicators also provide for the division of the data set into three subgroups according to the magnitude of variability. This division is statistically significant at a confidence level of 0.99 in both approaches, however, the division into sub-groups is slightly different in these methods. It was shown that the proposed indicators of the variability of SaO2 signals are scale-invariant, that is, they do not depend on the length of observation interval. This is a consequence of the fractality of the positions of differentials in the observation interval. The established switch frequencies for subgroups in order of increasing variability are (0.06, 0.11, and 0.20) Hz. These frequencies are manifested on Fourier spectra of differentials of SaO2

MET-4 Clinical investigation of the cases recurred as dissemination after postoperative local irradiation for metastatic brain tumors

Last year, the authors examined the outcome of the patients with metastatic brain tumor (MBT)treated by whole-brain irradiation (WBRT)or local irradiation (LRT)after surgery. As a result, it was shown that the overall survival (OS) was same but the recurrence pattern was different. Furthermore, it was shown that there were some cases with disseminated recurrence in the LRT group. One year has passed, cases showing disseminated recurrence after LRT were examined. The subjects were 28 patients for whom LRT was selected as post-surgical irradiation since December 2017, with an average age of 66.2 years and a male-female ratio of 19: 9. Non-small cell lung cancer was the most in 17 cases. During the observation period, recurrence was observed in 12 cases, new outbreaks at other sites in 8 cases, disseminated recurrence in 4 cases, and no local recurrence. There was no clear difference in kinds of carcinoma and removal fashion between disseminated recurrence cases and other cases. Disseminated recurrence occurred between 3–10 months after surgery, 2 presented with headache, 1 with convulsions, 1 confirmed during follow-up of images, and all underwent WBRT. The lesions shrank after irradiation, but they were easy to re-grow, and the prognosis was poor. On the other hand, 10 cases died in 24 cases other than disseminated recurrence, but all cases died of primary cancer. Although LRT after surgery is non-inferior to WBRT in terms of OS and has the advantage of maintaining cognitive function, this study shows that there is a considerable risk of disseminated recurrence regardless of the removal fashion or kinds of carcinoma. It was also shown that prognosis after disseminated recurrence was poor. It is desirable to select postoperative irradiation after explaining the recurrence pattern, and when LRT is adopted, it is necessary to consider setting a short observation interval immediately after irradiation.

A Rolling Panel Model of Cohort, Period, and Aging Effects for the Analysis of the General Social Survey

The linear dependence of age, period, and birth cohort is a challenge for the analysis of social change. With either repeated cross-sectional data or conventional panel data, raw change cannot be decomposed into over-time differences that are attributable to the effects of common experiences of alternative birth cohorts, features of the periods under observation, and the cumulation of lifecourse aging. This article proposes a rolling panel model for cohort, period, and aging effects, suggested by and tuned to the treble panel data collected for the General Social Survey from 2006 through 2014. While the model does not offer a general solution for the identification of the classical age-period-cohort accounting model, it yields warranted interpretations under plausible assumptions that are reasonable for many outcomes of interest. In particular, if aging effects can be assumed to be invariant over the course of an observation interval, and if separate panel samples of the full age distribution overlap within the same observation interval, then period and aging effects can be parameterized and interpreted separately, adjusted for cohort differences that pulse through the same observation interval. The estimated cohort effects during the observation interval are then interpretable as effects during the observation interval of entangled period and cumulated aging differences from before the observation interval.

Calving Management: A Questionnaire Survey of Veterinary Subject Matter Experts and Non-Experts

Accurate detection of the onset of parturition is a key factor in the prevention of dystocia. In order to establish current best practice recommendations for calving management, we asked subject matter experts (SME) who had published on calving management (by online survey, n = 80) and non-SMEs, veterinary practitioners (by workshop survey, n = 24) for their opinions. For this, we designed a questionnaire on the significance of signs of imminent parturition (SIP), the frequency of calving observation, and influencing factors for the timing of cow movement to a maternity pen. The response rate was 67.5% in the online survey and 100% in the workshop survey. The majority (89.7%) of all respondents agreed that it is beneficial for successful calving management to differentiate between stage I and II of parturition. Of 12 signs of imminent parturition (for stage I and II), “restlessness” and “visibility of fetal parts in vulva” were cited by 56.5% and 73.3% of SME and non-SME respondents, respectively. There was no consensus on the right time to move the cow to the maternity pen; recommendations varied from one to over 21 days. Almost half of the respondents (45.7%) recommended a 6-hour observation interval for prepartum cows in the maternity pen. This study identified a strong consensus on the SIP and how and when to observe cows prior to parturition. SMEs and non-SMEs provided broadly similar recommendations, while the SMEs and the non-SMEs differed significantly in the number of publications on calving they authored, they differed little in their knowledge of calving management.

NOISE IMMUNITY IN DATA COMPRESSION INFORMATION AND MEASUREMENT SYSTEMS

When processing huge data streams in information systems, individual measurements or whole groups of measurements can be distorted or lost due to various reasons. Recovery of compressed data during transmission on communication channels is accompanied by errors related to distortion of information and service parts of messages due to presence of interference in transmission channel. To these errors are added errors caused by quantization of the transmitted implementations by level and time sampling. Research on methods of increasing noise immunity both during transmission and during recovery of measured data is an urgent task in the design of information and measurement systems. The article considers non-parametric methods of estimating probabilistic characteristics of random processes. A distinctive feature of non-parametric methods is the ranking of data measured at the observation interval. It is shown that ranking of data on transmitting side of information-measuring system enables correction of errors and failures based on strict monotony of ranked number of codes. Also, the error of recovery of continuous implementations taking into account distortions of compressed data in the communication channel was investigated. The obtained results indicate that the use of complex compression algorithms is impractical, since the difference in the error in the restoration of non-stationary messages between the simplest algorithm and the rather difficult one becomes negligible. The article presents the results of estimating recovery errors for various data compression methods.

ALGORITHMIC METHOD OF AUTONOMOUS CORRECTION MEASUREMENT ERRORS IN SYSTEMS AUTOMATIC CONTROL AND REGULATION

A method of autonomous a posteriori estimation of control target’s state coordinates is demonstrated. The method’s accuracy does not depend on automatic control system sensors errors. An algorithmic implementation of the method is proposed – an algorithm for processing the array of data on the control target observed inputs and outputs, obtained by passive information accumulation during the observation interval of the control target normal functioning. At the final stage of the estimation algorithm, the implemented control process is simulated with complete a priori information about the conditions for its implementation (simulation estimation method). The algorithm execution time should be negligible in relation to the duration of the observation interval (instantaneous a posteriori estimation of the control target’s state). The proposed method allows to cyclically correct instrumental errors of automatic control and regulation systems without using external sources of information.

Volumetric growth rates of untreated cavernous sinus meningiomas

OBJECTIVE Meningiomas that arise primarily within the cavernous sinus are often believed to be more indolent in their growth pattern. Despite this perceived growth pattern, disabling symptoms can arise even with small tumors. While research has been done on cavernous sinus meningiomas (CSMs) and their treatment, very little is known about their natural growth rates. With a better understanding of the growth rate of CSM, patient treatment and guidance can be can optimized and individualized. The goal of this study was to determine volumetric growth rates of untreated CSMs. METHODS Thirty-seven patients with 166 MR images obtained between May 2004 and September 2019 were reviewed, with a range of 2–13 MR images per patient (average of 4.5 MR images per patient). These scans were obtained over an average follow-up period of 45.9 months (median 33.8, range 2.8–136.9 months). All imaging prior to any intervention was included in this analysis. Volumetric measurements were performed and assessed over time. RESULTS The estimated volumetric growth rate was 23.3% per year (95% CI 10.2%–38.0%, p < 0.001), which is equivalent to an estimated volume doubling time (VDT) of 3.3 years (95% CI 2.1–7.1 years). There was no significant relationship between growth rate and patient age (p = 0.09) or between growth rate and patient sex (p = 0.78). The median absolute growth rate was 41% with a range of −1% to 1793%. With a definition of “growth” as an increase of greater than 20% during the observed period, 65% of tumors demonstrated growth within their observation interval. Growth rates for each tumor were calculated and tumors were segmented based on growth rate. Of 37 patients, 22% (8) demonstrated no growth (< 5% annual growth, equivalent to a VDT > 13.9 years), 32% (12) were designated as slow growth (annual growth rate 5%–20%, VDT 3.5–13.9 years), 38% (14) were found to have medium growth (annual growth rate 20%–100%, VDT 0.7–3.5 years), and 8% were considered fast growing (annual growth rate > 100%, VDT < 0.7 years). CONCLUSIONS This study evaluated CSM volumetric growth rates. A deeper understanding of the natural history of untreated CSMs allows for better counseling and management of patients.

The Global Satellite Precipitation Constellation: current status and future requirements

To address the need to map precipitation on a global scale a collection of satellites carrying passive microwave (PMW) radiometers has grown over the last 20 years to form a constellation of about 10-12 sensors at any one time. Over the same period, a broad range of science and user communities has become increasingly dependent on the precipitation products provided by these sensors. The constellation presently consists of both conical and cross-track scanning precipitation-capable multi-channel instruments, many of which are beyond their operational and design lifetime but continue to operate through the cooperation of the responsible agencies. The Group on Earth Observations and the Coordinating Group for Meteorological Satellites (CGMS), among other groups, have raised the issue of how a robust, future precipitation constellation should be constructed. The key issues of current and future requirements for the mapping of global precipitation from satellite sensors can be summarised as providing: 1) sufficiently fine spatial resolutions to capture precipitation-scale systems and reduce the beam-filling effects of the observations; 2) a wide channel diversity for each sensor to cover the range of precipitation types, characteristics and intensities observed across the globe; 3) an observation interval that provides temporal sampling commensurate with the variability of precipitation; and 4) precipitation radars and radiometers in low inclination orbit to provide a consistent calibration source, as demonstrated by the first two spaceborne radar/radiometer combinations on the Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) mission Core Observatory (CO). These issues are critical in determining the direction of future constellation requirements, while preserving the continuity of the existing constellation necessary for long-term climate-scale studies.