scholarly journals Выбор порога селекции сигнала по уровню в обнаружителях с нормализованным индикаторным процессом

2020 ◽  
Author(s):  
S.B. Egorov ◽  
R.I. Gorbachev
Keyword(s):  
False Alarm ◽  
Probabilistic Model ◽  
Numerical Estimate ◽  
Threshold Value ◽  
Threshold Level ◽  
Probability Of False Alarm ◽  
Autonomous Mode ◽  
The Mean ◽  
The Moment

Предложена вероятностная модель работы автономного обнаружителя на этапе ожидания сигнала, когда момент появления сигнала неизвестен и по этой причине решающая статистика, сравниваемая с порогом, формируется непрерывно во времени в режиме скользящего окна . Ложная тревога в этом случае эквивалентна появлению хотя бы одного выброса помехового индикаторного процесса выше порога на максимально возможном интервале ожидания сигнала. Высота порога такова, что ложные выбросы являются редкими событиями, подчиняющимися закону Пуассона. На основе такой вероятностной модели показано, что вероятность ложной тревоги равна среднему числу ложных выбросов на максимально возможном интервале ожидания сигнала. Для обнаружителей с нормализованным индикаторным процессом получены соотношения, определяющие порог селекции сигнала по заданной вероятности ложной тревоги на заданном максимально возможном интервале ожидания сигнала. Показано, что в определении порога важную роль играет средняя квадратичная частота флюктуаций помехового индикаторного процесса. Дана численная оценка увеличения порога по сравнению с его значением, определенным по вероятности ложной тревоги в точке . Показано, что определение порога по предложенной методике особенно актуально для обнаружителей, работающих в длительном автономном режиме.This article proposes a probabilistic model of the autonomous detector in standby mode, when the moment of the signal appearance is unknown and for this reason the decisive statistics is generated continuously in time in the sliding window mode and compared with the threshold value. In this case, false alarm is equivalent to the appearance of at least one outlier of the jamming indicator process above the threshold at the maximum possible signal waiting interval. The threshold level match case when the false alarm are rare events and obey the Poisson law of distribution. Based on such a probabilistic model, we show that the probability of a false alarm is equal to the average number of false emissions at the maximum possible interval for a signal waiting. For detectors with a normalized indicator process, are obtained relations that determine the threshold for signal selection by a given probability of false alarm at a given maximum possible signal waiting interval. It is shown that in determining the threshold, the mean square frequency of fluctuations of the interference indicator process plays an important role. Also, a numerical estimate of the increase in the threshold is given compared with its value determined by the probability of false alarm at a point . It is shown that the determination of the threshold by the proposed method is especially relevant for detectors operating in a long autonomous mode.

scholarly journals Two-dimensional Determination of the Decision Boundary for a Radar Detection Method in the Moment Space

2019 ◽  
Author(s):  
Camilo Guillén ◽  
Nelson Chávez
Keyword(s):  
Detection Method ◽  
Geometric Interpretation ◽  
Two Dimensions ◽  
Decision Boundary ◽  
Two Dimensional ◽  
Radar Detection ◽  
Probability Of False Alarm ◽  
Pearson Criterion ◽  
The Moment

The radar detection with decision making in the moments space (DRACEC method) is based on a statistical analysis to determine the boundary between the background (absent target) and the anomaly (present target) classes. In this article, the boundary is taken as an ellipse and is calculated for two dimensions, emphasizing its geometric interpretation. The procedures to establish the shape, location, and size of the ellipse are highlighted, guaranteeing the probability of false alarm by applying the Neyman-Pearson criterion. The proposal establishes a methodology for calculation of the boundary when it is required to use the moments directly as a sufficient decision statistic.

scholarly journals Discontinuous gas exchange in Madagascan hissing cockroaches is not a consequence of hysteresis around a fixed PCO2 threshold

2022 ◽  
Author(s):  
Tormod T. C. Rowe ◽  
Martin S. Gutbrod ◽  
Philip G. D. Matthews
Keyword(s):  
Gas Exchange ◽  
Feedback Loop ◽  
Ventilatory Threshold ◽  
Threshold Value ◽  
Threshold Level ◽  
O2 Uptake ◽  
Ventilatory Control ◽  
Characteristic Oscillation ◽  
The Mean ◽  
Co2 Release

It has been hypothesised that insects display discontinuous gas-exchange cycles (DGCs) due to hysteresis in their ventilatory control, where CO2-sensitive respiratory chemoreceptors respond to changes in hemolymph PCO2 only after some delay. If correct, DGCs would be a manifestation of an unstable feedback loop between chemoreceptors and ventilation causing PCO2 to oscillate around some fixed threshold value: PCO2 above this ventilatory threshold would stimulate excessive hyperventilation, driving PCO2 below the threshold and causing a subsequent apnoea. This hypothesis was tested by implanting micro-optodes into the hemocoel of Madagascar hissing cockroaches and measuring hemolymph PO2 and PCO2 simultaneously during continuous and discontinuous gas exchange. The mean hemolymph PCO2 of 1.9 kPa measured during continuous gas exchange was assumed to represent the threshold level stimulating ventilation, and this was compared with PCO2 levels recorded during DGCs elicited by decapitation. Cockroaches were also exposed to hypoxic (PO2 10 kPa) and hypercapnic (PCO2 2 kPa) gas mixtures to manipulate hemolymph PO2 and PCO2. Decapitated cockroaches maintained DGCs even when their hemolymph PCO2 was forced above or below the putative ∼2 kPa ventilation threshold, demonstrating that the characteristic oscillation between apnoea and gas exchange is not driven by a lag between changing hemolymph PCO2 and a PCO2 chemoreceptor with a fixed ventilatory threshold. However, it was observed that the gas exchange periods within the DGC were altered to enhance O2 uptake and CO2 release during hypoxia and hypercapnia exposure. This indicates that while respiratory chemoreceptors do modulate ventilatory activity in response to hemolymph gas levels, their role in initiating or terminating the gas exchange periods within the DGC remains unclear.

Aktivitätskonzentration der vom Personal einer Radiojodtherapiestation eingeatmeten Luft

1987 ◽  
Vol 26 (03) ◽  
pp. 143-146 ◽  
Author(s):  
H. Fill ◽  
M. Oberladstätter ◽  
J. W. Krzesniak
Keyword(s):  
Nuclear Medicine ◽  
Length Of Stay ◽  
Activity Concentration ◽  
Threshold Value ◽  
Whole Body ◽  
Therapeutic Activity ◽  
External Radiation ◽  
Oral Application ◽  
Exhaled Air ◽  
The Mean

The mean activity concentration of1311 during inhalation by the nuclear medicine personnel was measured at therapeutic activity applications of 22 GBq (600 mCi) per week. The activity concentration reached its maximum in the exhaled air of the patients 2.5 to 4 hours after oral application. The normalized maximum was between 2 • 10−5 and 2 • 10−3 Bq-m−3 per administered Bq. The mean activity concentration of1311 inhaled by the personnel was 28 to 1300 Bq-m−3 (0.8 to 35 nCi-rrf−3). From this the1311 uptake per year was estimated to be 30 to 400 kBq/a (x̄ = 250, SD = 50%). The maximum permitted uptake from air per year is, according to the German and Austrian radiation protection ordinances 22/21 µiCi/a (= 8 • 105 Bq/a). At maximum 50% and, on the average, 30% of this threshold value are reached. The length of stay of the personnel in the patient rooms is already now limited to such an extent that 10% of the maximum permissible whole-body dose for external radiation is not exceeded. Therefore, increased attention should be paid also to radiation exposure by inhalation.

Detection of Circulating Tissue Factor and Factor VII in a Normal Population

1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Normal Population ◽  
Mean Value ◽  
Factor Vii ◽  
Significant Difference ◽  
Age Dependent ◽  
The Mean ◽  
Highly Correlated ◽  
And Gender

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.

Determination of Plasminogen in Clots and Thrombi

1966 ◽  
Vol 16 (01/02) ◽  
pp. 038-050 ◽  
Author(s):  
Ulla Hedner ◽  
Inga Marie Nilsson ◽  
B Robertson
Keyword(s):  
Mean Value ◽  
Main Mechanism ◽  
Clot Lysis ◽  
Post Mortem ◽  
Digestion Time ◽  
Normal Volunteers ◽  
Casein Solution ◽  
The Mean

SummaryThe plasminogen content was determined by a casein method in plasma and serum from 20 normal volunteers. The mean plasminogen content was found to be 10.1 ACU (the arbitrary caseinolytic unit defined in such a way that using a 3% casein solution and a digestion time of 20 min. at 37°C, 10 ACU gave an extinction of 0.300). No difference between serum and plasma regarding the plasminogen content was found.Plasminogen was determined in drained and drained plus washed clots prepared from 2 ml plasma. The highest values found in the drained clots were 0.9 ACU/clot and 0.2 ACU/clot in the drained plus washed clots.Plasminogen was also determined in drained and drained plus washed clots prepared from plasma with added purified plasminogen. The plasminogen was recovered in the washing fluid. According to these tests, then, purified added plasminogen is washed out of the clots.The plasminogen content of 20 thrombi obtained post mortem was also determined. The mean value was found to be 0.7 ACU/cm thrombus. Judging from our results, the “intrinsic clot lysis theory” is not the main mechanism of clot dissolution.

SERUM TRIIODOTHYRONINE DETERMINATION BY SATURATION ANALYSIS

1973 ◽  
Vol 72 (4) ◽  
pp. 714-726 ◽  
Author(s):  
A. Burger ◽  
B. Miller ◽  
C. Sakoloff ◽  
M. B. Vallotton
Keyword(s):  
Ionic Strength ◽  
Limit Of Detection ◽  
Improved Method ◽  
Accuracy Of Measurement ◽  
Tracer Amount ◽  
The Mean ◽  
Physiological Values ◽  
Hyperthyroid Patients ◽  
Solvent Blank

ABSTRACT An improved method for the determination of serum triiodothyronine (T3) has been developed. After addition of a tracer amount of the hormone, T3 was extracted from 1 ml serum under conditions of pH and ionic strength which favoured T3 extraction (89%) over thyroxine (T4) extraction (58%). Chromatography of the extracted material on Sephadex LH-20 separated T3 completely from residual T4. The T3 eluate was dried, then re-dissolved in 0.5 ml NaOH 0.04 n. To 0.2 ml duplicate aliquots, a standard amount of TBG was added for the competitive protein analysis. After one hour incubation at 4°C, separation of bound from free T3 was achieved on small Sephadex G-25 columns. Overall recovery was 67 ± 10.8% and correction for the loss was made. The solvent blank was 37 ± 27 (sd) ng/100 ml. Accuracy of measurement of known quantities of T3 added to serum was 98.4%. The coefficient of variation within the assay was 6.2% and between the assays it was 11.4%. The limit of detection (0.1 ng) corresponded to a concentration of 25 ng/100 ml. T4 added to serum did not interfere with T3 determination until high non-physiological values were reached. The mean ± sd serum T3 in 54 euthyroid subjects was 153 ± 58 ng/100 ml and in 24 hyperthyroid patients it was 428 ±186 ng/100 ml; 4 out of the 24 hyperthyroid values were within 2 sd of the mean euthyroid group. All the values found in the euthyroid group were well above the limit of detection of the method.

Determination of the Probability Distribution of the Mean Sound Level

2010 ◽  
Vol 35 (4) ◽  
pp. 543-550 ◽  
Author(s):  
Wojciech Batko ◽  
Bartosz Przysucha
Keyword(s):  
Probability Distribution ◽  
Probability Distribution Function ◽  
Mean Value ◽  
Sound Level ◽  
Function Form ◽  
Noise Levels ◽  
Logarithmic Mean ◽  
The Mean ◽  
Estimation Of Uncertainty

AbstractAssessment of several noise indicators are determined by the logarithmic mean <img src="/fulltext-image.asp?format=htmlnonpaginated&src=P42524002G141TV8_html\05_paper.gif" alt=""/>, from the sum of independent random resultsL1;L2; : : : ;Lnof the sound level, being under testing. The estimation of uncertainty of such averaging requires knowledge of probability distribution of the function form of their calculations. The developed solution, leading to the recurrent determination of the probability distribution function for the estimation of the mean value of noise levels and its variance, is shown in this paper.

PREDICTION OF THE EFFICIENCY OF RECONSTRUCTIVE INTERVENTIONS ON THE MAJOR NERVES OF THE FOREARM, DEPENDING ON THE DEFECT DURATION AND THE FOLLOWING REHABILITATION

2020 ◽  
pp. 77-88
Author(s):  
Дмитрий Валериевич Судаков ◽  
Олег Валериевич Судаков ◽  
Людмила Валентиновна Кретинина ◽  
Наталья Владимировна Якушева ◽  
Артём Николаевич Шевцов
Keyword(s):  
Nervous Tissue ◽  
Clinical Situation ◽  
Economic Importance ◽  
Important Data ◽  
Subsequent Period ◽  
Complete Restoration ◽  
Reconstructive Microsurgery ◽  
The Moment

Статья посвящена построению прогноза эффективности реконструктивных вмешательств на магистральных нервах предплечья в зависимости от протяженности дефекта нервной ткани и особенностей последующего периода реабилитации пациентов. Данная тематика является весьма актуальной, так как с каждым годом во всем мире наблюдается определенный рост случаев травм различного генеза магистральных нервных стволов, которые затем нередко приводят к временной нетрудоспособности и даже инвалидности пациентов. Реконструктивная микрохирургия многие десятилетия пытается решить целый ряд проблем аутотрансплантации нервных стволов и повысить ее общую эффективность. Но из-за определенных проблем связанных с финансированием, некоторые вопросы трансплантологии и реабилитации остаются нерешенными и в настоящий момент. Все это придает представленной работе важное значение не только медицинского, но и социально - экономического плана. Целью работы стала попытка построения прогноза восстановительных операций на нервной ткани, с учетом объема пораженных структур и периода реабилитации. Объектами исследования стало 180 больных, которым по той или иной причине, осуществлялась реконструктивная операция на одном из магистральных нервов предплечья. Все пациенты были разделены на 3 группы по 60 человек, в зависимости от протяженности дефекта магистрального нерва: до 4 см, от 4 до 8 см и от 8 до 12 см. Последующее разделение внутри каждой группы на подгруппы производилось в зависимости от определенного поврежденного нерва (лучевой, локтевой, срединный). В работе изучалось течение раннего послеоперационного воспалительного процесса, с определением бактериальной микрофлоры в ране. Изучались и отдаленные последствия оперативного вмешательства. Своеобразной новизной для данной тематики в целом, стало выявление последующего установления инвалидности пациентов. Кроме того, важные данные были получены и по срокам реабилитации и частичного или полного восстановления утраченных функций по срокам в зависимости от размеров восстанавливаемого дефекта и от наличия или отсутствия необходимой реабилитации. Полученные в работе данные могут представлять интерес не только для врачей хирургов и травматологов, но и для организаторов здравоохранения, позволяя производить прогнозы по выздоровлению пациентов в каждой определенной клинической ситуации The article is devoted to the construction of a forecast of the effectiveness of reconstructive interventions on the main nerves of the forearm, depending on the length of the defect in the nervous tissue and the characteristics of the subsequent period of rehabilitation of patients. This topic is very relevant, since every year all over the world there is a certain increase in cases of injuries of various origins of the main nerve trunks, which then often lead to temporary disability and even disability of patients. For many decades, reconstructive microsurgery has been trying to solve a number of problems of autotransplantation of nerve trunks and improve its overall efficiency. But due to certain problems associated with funding, some issues of transplantation and rehabilitation remain unresolved at the moment. All this gives the presented work important not only medical, but also socio - economic importance. The aim of this work was to attempt to predict restorative operations on the nervous tissue, taking into account the volume of the affected structures and the period of rehabilitation. The objects of the study were 180 patients who, for one reason or another, underwent a reconstructive operation on one of the main nerves of the forearm. All patients were divided into 3 groups of 60 people, depending on the length of the main nerve defect: up to 4 cm, from 4 to 8 cm, and from 8 to 12 cm. Subsequent division within each group into subgroups was performed depending on the specific damaged nerve ( radial, ulnar, median). The work studied the course of the early postoperative inflammatory process, with the determination of bacterial microflora in the wound. The long-term consequences of surgery were also studied. A peculiar novelty for this topic as a whole was the identification of the subsequent establishment of disability in patients. In addition, important data were obtained on the timing of rehabilitation and partial or complete restoration of lost functions in terms of timing, depending on the size of the restored defect and on the presence or absence of the necessary rehabilitation. The data obtained in this work may be of interest not only for surgeons and traumatologists, but also for healthcare organizers, allowing them to make predictions about the recovery of patients in each specific clinical situation

Simultaneous Determination of Alogliptin, Linagliptin, Saxagliptin, and Sitagliptin in Bulk Drug and Formulation by UPLC Q-TOF-MS

2020 ◽  
Vol 17 (1) ◽  
pp. 95-105
Author(s):  
Ramji Rathod ◽  
Faraat Ali ◽  
Amrish Chandra ◽  
Robin Kumar ◽  
Meenakshi Dahiya ◽  
...  
Keyword(s):  
Internal Standard ◽  
Gradient Elution ◽  
Ultra Performance Liquid Chromatography ◽  
Pharmaceutical Dosage Forms ◽  
Sensitivity And Selectivity ◽  
The Mean ◽  
Bulk Drug ◽  
Positive Ion ◽  
Higher Sensitivity

Background: A simple and sensitive Ultra Performance Liquid Chromatography-Mass Spectrometry method was developed and validated to measure the concentrations of Alogliptin (ALO), Linagliptin (LIN), Saxagliptin (SAX), and Sitagliptin (SIT) using Pioglitazone (PIO) as an internal standard. Methods: Chromatographic separation of six gliptins was achieved on a C-18 column (100×2.1 mm, 2.7 μm) using a mobile phase consisting of formic acid in water, 0.1%v/v: acetonitrile in gradient elution. Electrospray ionization (ESI) source was operated in the positive ion mode. Targeted MS/MS mode on a QTOF MS was used to quantify the drug utilizing the transitions of 340.1(m/z), 473.2 (m/z), 316.2 (m/z), 408.1 (m/z), and 357.1 (m/z) for ALO, LIN, SAX, SIT and PIO respectively. Results: As per ICH Q2R1 guidelines, a detailed validation of the method was carried out and the standard curves were found to be linear over the concentration ranges of 1516.0-4548.1 ng mL-1, 519.8- 1559.4 ng mL-1, 1531.4-4594.3 ng mL-1and 1519.6-4558.8 ng mL-1 for ALO, LIN, SAX and SIT respectively. Precision and accuracy results were within the acceptable limits. The mean recovery was found to be 98.8 _ 0.76 % (GEM), 102.2 _ 1.59 % (LIN), 95.3 _ 2.74 % (SAX) and 99.2 _ 1.75 % (SIT) respectively. Conclusions: The optimized validated UPLC QTOF-MS/MS method offered the advantage of shorter analytical times and higher sensitivity and selectivity. The optimized method is suitable for application in quantitative analysis of pharmaceutical dosage forms for QC laboratory.

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