scholarly journals Adaptive Early Warning Method Based on Similar Proportion and Probability Model

2020 ◽  
Vol 10 (12) ◽  
pp. 4278
Author(s):  
Yazhou Li ◽  
Wei Dai ◽  
Tingting Huang ◽  
Meihua Shi ◽  
Weifang Zhang
Keyword(s):  
Early Warning ◽  
Probability Model ◽  
Similar Proportion ◽  
False Alarms ◽  
Mechanical Equipment ◽  
Threshold Method ◽  
Health States ◽  
Number Of False Alarms ◽  
Fixed Threshold ◽  
Equipment State

This paper presents a multi-state adaptive early warning method for mechanical equipment and proposes an adaptive dynamic update model of the equipment alarm threshold based on a similar proportion and state probability model. Based on the similarity of historical equipment, the initial thresholds of different health states of equipment can be determined. The equipment status is divided into four categories and analyzed, which can better represent its status and provide more detailed and reasonable guidance. The obtained dynamic alarm lines at all levels can regulate the operation range of equipment in the different health states. Compared to the traditional method of a fixed threshold, this method can effectively reduce the number of false alarms and attains a higher prediction accuracy, which demonstrates its effectiveness and superiority. Finally, the method was verified by means of lifetime data of a rolling bearings. The results show that the model improves the timely detection of the abnormal state of the equipment, greatly reduces the false alarm rate, and even overcomes the limitation of independence between the fixed threshold method and equipment state. Moreover, multi-state division can accurately diagnose the current equipment state, which should be considered in maintenance decision-making.

scholarly journals Determination of level and time thresholds for detectors with normalized indicator process

2020 ◽  
Author(s):  
С.Б. Егоров ◽  
Р.И. Горбачев
Keyword(s):  
False Alarm ◽  
Average Rate ◽  
Probability Model ◽  
False Alarm Probability ◽  
Statistical Characteristics ◽  
False Alarms ◽  
Time Interval ◽  
Number Of False Alarms ◽  
Time Threshold ◽  
Selection Threshold

«Выбросовая» вероятностная модель работы обнаружителя в режиме ожидания сигнала, предложенная авторами в [1], использована для оценки влияния селекции выбросов по длительности на вероятность ложной тревоги. Флюктуационные выбросы помехового индикаторного процесса, превысившие пороги селекции по уровню и длительности, трактуются как редкие события на интервале ожидания сигнала, подчиняющиеся вероятностному закону Пуассона. При условии, что средний период следования ложных выбросов превышает интервал корреляции индикаторного процесса, получено соотношение между средним числом выбросов любой длительности и средним числом выбросов, превысивших пороговую длительность. На основании известных числовых и вероятностных характеристик выбросов нормального стационарного случайного процесса получен уравнения, связывающие относительные пороги селекции по уровню и длительности с вероятностью ложной тревоги на интервале ожидания сигнала. Предложена методика определения порога селекции по длительности для снижения порога селекции по уровню до заданной величины. «Emissional» probability model of the detector in stand-by mode proposed by the authors in [1], is intended for estimation of false alarm rate dependence from the value of time-selection threshold. Fluctuation emissions of the noise indicator process are interpreted as rare events correspond to Poisson distribution. Assuming that average rate of false alarms exceeds the correlation interval of indicator process, obtained equation between average number of false alarms of any duration and average number of false alarms exceed the time threshold. Based on known numerical and statistical characteristics of emissions of normal stationary random process obtained equations, relating time and level thresholds with false alarm probability on stand-by mode time interval. Also suggested a method of determining time threshold intended to reduce level threshold.

scholarly journals IoT-Based Geotechnical Monitoring of Unstable Slopes for Landslide Early Warning in the Darjeeling Himalayas

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2611 ◽  
Author(s):  
Minu Treesa Abraham ◽  
Neelima Satyam ◽  
Biswajeet Pradhan ◽  
Abdullah M. Alamri
Keyword(s):  
Water Content ◽  
Early Warning ◽  
False Alarms ◽  
Data Logger ◽  
Rainfall Thresholds ◽  
Number Of False Alarms ◽  
The World ◽  
Landslide Early Warning ◽  
Tilt Sensors ◽  
Darjeeling Himalayas

In hilly areas across the world, landslides have been an increasing menace, causing loss of lives and properties. The damages instigated by landslides in the recent past call for attention from authorities for disaster risk reduction measures. Development of an effective landslide early warning system (LEWS) is an important risk reduction approach by which the authorities and public in general can be presaged about future landslide events. The Indian Himalayas are among the most landslide-prone areas in the world, and attempts have been made to determine the rainfall thresholds for possible occurrence of landslides in the region. The established thresholds proved to be effective in predicting most of the landslide events and the major drawback observed is the increased number of false alarms. For an LEWS to be successfully operational, it is obligatory to reduce the number of false alarms using physical monitoring. Therefore, to improve the efficiency of the LEWS and to make the thresholds serviceable, the slopes are monitored using a sensor network. In this study, micro-electro-mechanical systems (MEMS)-based tilt sensors and volumetric water content sensors were used to monitor the active slopes in Chibo, in the Darjeeling Himalayas. The Internet of Things (IoT)-based network uses wireless modules for communication between individual sensors to the data logger and from the data logger to an internet database. The slopes are on the banks of mountain rivulets (jhoras) known as the sinking zones of Kalimpong. The locality is highly affected by surface displacements in the monsoon season due to incessant rains and improper drainage. Real-time field monitoring for the study area is being conducted for the first time to evaluate the applicability of tilt sensors in the region. The sensors are embedded within the soil to measure the tilting angles and moisture content at shallow depths. The slopes were monitored continuously during three monsoon seasons (2017–2019), and the data from the sensors were compared with the field observations and rainfall data for the evaluation. The relationship between change in tilt rate, volumetric water content, and rainfall are explored in the study, and the records prove the significance of considering long-term rainfall conditions rather than immediate rainfall events in developing rainfall thresholds for the region.

Triggers for the Transient State of a Pipeline in Material Balance Systems Used in Real-Time Transient Hydraulic Modeling

2014 ◽  
Author(s):  
Noorallah Rostamy ◽  
Norense Okungbowa ◽  
John D. Yurchevich
Keyword(s):  
Steady State ◽  
Material Balance ◽  
Transient State ◽  
Leak Detection ◽  
Hydraulic Modeling ◽  
False Alarms ◽  
Threshold Method ◽  
Flow Meter ◽  
Transient Event ◽  
Number Of False Alarms

Computational Pipeline Monitoring (CPM) leak detection in liquid pipelines can be unreliable or have a high number of false alarms during transient hydraulic events. This paper presents techniques for avoiding these false alarms and for improving leak detectability during steady state operations. Application of this approach has improved both the sensitivity and reliability of CPM-based leak detection systems. When a pipeline is in steady-state operation, the leak detection thresholds can be reduced. When a transient is detected, the thresholds are increased to a higher value. Because of known errors in data measurement and the time at which the measurement was made, large uncertainties in the line-pack prediction can exist during these transient events. In this paper, CPM reliability is improved using dual thresholds; tight threshold for near steady state and relaxed threshold for transient operation. In the presented study, different transient triggers in a pipeline have been implemented to the dual threshold method in order to show the effect of transient thresholds on the reliability of the CPM models or the reduction in the number of false alarms. When the CPM model determines that a transient event is occurring, the imbalance threshold is increased to a pre-set higher value. The transient threshold will remain high until the transient event diminishes, then the thresholds will return to their original steady-state value after a pre-set wait period. This applies to each leak detection window and to each flow meter-to-flow meter section in the CPM model. Detailed information about the dual thresholds approach and the transient triggers is provided in the full paper. Results from the implementation of this method and the quantitative improvement of the CPM reliability and sensitivity will also be presented.

Algorithms for detecting broadband signals with a constant level of false alarms

2021 ◽  
Author(s):  
I.F. Lozovskiy
Keyword(s):  
Detection Threshold ◽  
Signal Amplitude ◽  
Rayleigh Distribution ◽  
Training Sample ◽  
Detection Algorithm ◽  
Constant Level ◽  
False Alarms ◽  
Interference Power ◽  
Number Of False Alarms ◽  
Distribution Type

The use of broadband souding signals in radars, which has become real in recent years, leads to a significant reduction in the size of resolution elements in range and, accordingly, in the size of the window in which the training sample is formed, which is used to adapt the detection threshold in signal detection algorithms with a constant level of false alarms. In existing radars, such a window would lead to huge losses. The purpose of the work was to study the most rational options for constructing detectors with a constant level of false alarms in radars with broadband sounding signals. The problem was solved for the Rayleigh distribution of the envelope of the noise and a number of non-Rayleigh laws — Weibull and the lognormal, the appearance of which is associated with a decrease in the number of reflecting elements in the resolution volume. For Rayleigh interference, an algorithm is proposed with a multi-channel in range incoherent signal amplitude storage and normalization to the larger of the two estimates of the interference power in the range segments. The detection threshold in it adapts not only to the interference power, but also to the magnitude of the «power jump» in range, which allows reducing the number of false alarms during sudden changes in the interference power – the increase in the probability of false alarms did not exceed one order of magnitude. In this algorithm, there is a certain increase in losses associated with incoherent accumulation of signals reflected from target elements, and losses can be reduced by certain increasing the size of the distance segments that make up the window. Algorithms for detecting broadband signals against interference with non-Rayleigh laws of distribution of the envelope – Weibull and lognormal, based on the addition of the algorithm for detecting signals by non-linear transformation of sample counts into counts with a Rayleigh distribution, are studied. The structure of the detection algorithm remains unchanged in practice. The options for detectors of narrowband and broadband signals are considered. It was found that, in contrast to algorithms designed for the Rayleigh distribution, these algorithms provide a stable level of false alarms regardless of the values of the parameters of non-Rayleigh interference. To reduce losses due to interference with the distribution of amplitudes according to the Rayleigh law, detectors consisting of two channels are used, in which one of the channels is tuned for interference with the Rayleigh distribution, and the other for lognormal or Weibull interference. Channels are switched according to special distribution type recognition algorithms. In such detectors, however, there is a certain increase in the probability of false alarms in a rather narrow range of non-Rayleigh interference parameters, where their distribution approaches the Rayleigh distribution. It is shown that when using broadband signals, there is a noticeable decrease in detection losses in non-Rayleigh noise due to lower detection thresholds for in range signal amplitudes incoherent storage.

An Automated Conflict-alert Function for an Air Traffic Control System

1980 ◽  
Vol 33 (3) ◽  
pp. 475-481
Author(s):  
P. Bertolazzi ◽  
M. Lucertini
Keyword(s):  
Decision Making ◽  
Control System ◽  
Traffic Control ◽  
Air Traffic Control ◽  
Air Traffic ◽  
False Alarms ◽  
Major Purpose ◽  
Number Of False Alarms ◽  
Traffic Control System

The major purpose of an air traffic control system is to ensure the separation of two or more aircraft flying in the same airspace, with an efficiency that can be expressed in terms of capacity and cost. As air traffic grows in numbers it becomes necessary to reduce the workload of the controllers by relieving them of many monitoring tasks, and eventually some decision-making tasks, through computerized automation. In this context many developments tend to build up an efficient conflict-alert subsystem.The problem of conflict-alert in the air needs strategic tools, to make collision unlikely or even impossible, and tactical tools to detect impending collisions. The latter detect potentially hazardous aircraft encounters and alert the controller in time to warn the pilots (if necessary) and should obviously provide this capability with a minimal number of false alarms and no increase in workload.

scholarly journals Detection of signals of moving objects based on the time selection method

2021 ◽  
Vol 66 (3) ◽  
pp. 335-342
Author(s):  
V. M. Artemiev ◽  
S. M. Kostromitsky ◽  
A. O. Naumov
Keyword(s):  
Moving Objects ◽  
Average Duration ◽  
Threshold Level ◽  
Selection Method ◽  
Probability Of Detection ◽  
False Alarms ◽  
Threshold Method ◽  
Detection Of Signals ◽  
Two Stages ◽  
Time Selection

To increase the efficiency of detecting moving objects in radiolocation, additional features are used, associated with the characteristics of trajectories. The authors assumed that trajectories are correlated, that allows extrapolation of the coordinate values taking into account their increments over the scanning period. The detection procedure consists of two stages. At the first, detection is carried out by the classical threshold method with a low threshold level, which provides a high probability of detection with high values of the probability of false alarms. At the same time uncertainty in the selection of object trajectory embedded in false trajectories arises. Due to the statistical independence of the coordinates of the false trajectories in comparison with the correlated coordinates of the object, the average duration of the first of them is less than the average duration of the second ones. This difference is used to solve the detection problem at the second stage based on the time-selection method. The obtained results allow estimation of the degree of gain in the probability of detection when using the proposed method.

scholarly journals Coupling ensemble weather predictions based on TIGGE database with Grid-Xinanjiang model for flood forecast

2011 ◽  
Vol 29 ◽  
pp. 61-67 ◽  
Author(s):  
H.-J. Bao ◽  
L.-N. Zhao ◽  
Y. He ◽  
Z.-J. Li ◽  
F. Wetterhall ◽  
...  
Keyword(s):  
Weather Prediction ◽  
Grid Cell ◽  
Flood Forecasting ◽  
False Alarms ◽  
Flood Forecast ◽  
Distributed Hydrological Model ◽  
Xinanjiang Model ◽  
Numerical Weather ◽  
Number Of False Alarms ◽  
Promising Tool

Abstract. The incorporation of numerical weather predictions (NWP) into a flood forecasting system can increase forecast lead times from a few hours to a few days. A single NWP forecast from a single forecast centre, however, is insufficient as it involves considerable non-predictable uncertainties and lead to a high number of false alarms. The availability of global ensemble numerical weather prediction systems through the THORPEX Interactive Grand Global Ensemble' (TIGGE) offers a new opportunity for flood forecast. The Grid-Xinanjiang distributed hydrological model, which is based on the Xinanjiang model theory and the topographical information of each grid cell extracted from the Digital Elevation Model (DEM), is coupled with ensemble weather predictions based on the TIGGE database (CMC, CMA, ECWMF, UKMO, NCEP) for flood forecast. This paper presents a case study using the coupled flood forecasting model on the Xixian catchment (a drainage area of 8826 km2) located in Henan province, China. A probabilistic discharge is provided as the end product of flood forecast. Results show that the association of the Grid-Xinanjiang model and the TIGGE database gives a promising tool for an early warning of flood events several days ahead.

Method for oil balance control under quasi-stationary modes of operation of an oil pipeline section with free flow

2021 ◽  
pp. 40-45
Author(s):  
Рустам Зайтунович Сунагатуллин ◽  
Антон Михайлович Чионов ◽  
Семен Васильевич Петренко
Keyword(s):  
Balance Control ◽  
Operation Mode ◽  
Rate Of Change ◽  
Free Flow ◽  
False Alarms ◽  
Oil Pipeline ◽  
Detection Systems ◽  
Pipeline Section ◽  
Number Of False Alarms ◽  
Oil Flow

Автоматизированные системы управления используются в нефтепроводном транспорте с целью автоматизации технологических процессов транспортировки нефти и нефтепродуктов, при этом основной задачей является обеспечение надежности и безопасности перекачки, что невозможно без контроля целостности трубопровода. В связи с этим актуальной остается тема обнаружения утечек, требуют продолжения исследования в области повышения надежности автоматизированных систем обнаружения утечек (СОУ). При эксплуатации СОУ особую важность представляет описание процессов заполнения и опорожнения участков трубопровода с безнапорным течением. Скорость установления стационарного режима работы таких участков и участков с полным сечением существенно отличается. Слабые возмущения давления могут приводить к значительному дебалансу расхода нефти и, как следствие, вызывать ложные срабатывания СОУ. Авторами представлен алгоритм вычисления скорости изменения запаса нефти на участке трубопровода при медленном изменении размера самотечной полости, на основании которого предложен способ корректировки уравнения баланса вещества. Показано использование разработанного алгоритма для повышения чувствительности СОУ и уменьшения количества ложных срабатываний. During the operation of leak detection systems (LDS), it is of great importance to describe the processes of filling and emptying pipeline free flow sections. The speed of establishing a stationary operation mode of such sections and full sections is significantly different. Weak pressure perturbations can lead to significant imbalance in the oil flow rate and, as a consequence, cause false LDS positives. The authors present an algorithm for calculating rate of change in oil reserve in the pipeline section with a slow change in the size of gravity cavity, on the basis of which a method for adjusting the substance balance equation is proposed. The use of a developed algorithm is shown to increase the sensitivity of LDS and reduce the number of false alarms.

Optimal Detection and Estimation of Marine Oil Spills Through Coherent Pluralism

2013 ◽  
Vol 4 (1) ◽  
pp. 84-111
Author(s):  
Kufre Bassey ◽  
Polycarp Chigbu
Keyword(s):  
Remote Sensing ◽  
Environmental Science ◽  
Oil Spills ◽  
False Alarms ◽  
Optical Remote Sensing ◽  
Marine Oil ◽  
Detection And Estimation ◽  
Number Of False Alarms ◽  
Marine Oil Spills ◽  
Remote Sensing Techniques

An important area of environmental science involves the combination of information from diverse sources relating to a similar endpoint. Majority of optical remote sensing techniques used for marine oil spills detection have been reported lately of having high number of false alarms (oil slick look-a-likes) phenomena which give rise to signals which appear to be oil but are not. Suggestions for radar image as an operational tool has also been made. However, due to the inherent risk in these tools, this paper presents the possible research directions of combining statistical techniques with remote sensing in marine oil spill detection and estimation.

What Do We Know About Buffer Overflow Detection?

2018 ◽  
Vol 9 (3) ◽  
pp. 1-33 ◽  
Author(s):  
Marcos Lordello Chaim ◽  
Daniel Soares Santos ◽  
Daniela Soares Cruzes
Keyword(s):  
Program Analysis ◽  
Ad Hoc ◽  
Symbolic Execution ◽  
Buffer Overflow ◽  
False Alarms ◽  
Memory Errors ◽  
Number Of False Alarms ◽  
Extensive Body ◽  
Inspection Techniques ◽  
Execution Models

Buffer overflow (BO) is a well-known and widely exploited security vulnerability. Despite the extensive body of research, BO is still a threat menacing security-critical applications. The authors present a comprehensive systematic review on techniques intended to detecting BO vulnerabilities before releasing a software to production. They found that most of the studies addresses several vulnerabilities or memory errors, being not specific to BO detection. The authors organized them in seven categories: program analysis, testing, computational intelligence, symbolic execution, models, and code inspection. Program analysis, testing and code inspection techniques are available for use by the practitioner. However, program analysis adoption is hindered by the high number of false alarms; testing is broadly used but in ad hoc manner; and code inspection can be used in practice provided it is added as a task of the software development process. New techniques combining object code analysis with techniques from different categories seem a promising research avenue towards practical BO detection.

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