scholarly journals Analysis of the Influence of Carried Out Repairs Efficiency on Transport Means Operational Reliability

2010 ◽  
Vol 14-15 (1) ◽  
pp. 359-376
Author(s):  
Andrzej Wdzięczny ◽  
Łukasz Muślewski
Keyword(s):  
Operational Reliability ◽  
Poor Quality ◽  
Transport Systems ◽  
Time Interval ◽  
Technical Object ◽  
Operation Analysis ◽  
Short Period ◽  
Functional Features ◽  
Destructive Processes ◽  
Interval Lengths

Analysis of the Influence of Carried Out Repairs Efficiency on Transport Means Operational Reliability The Maintenance factors and destructive processes which affect systems and elements of technical objects result in undesirable changes of values of their functional features, which causes damages. A damage to a technical object has been defined as exceeding permitted boundary values by significant features characterizing their elements. On the basis of analysis results of the author's own research concerning damages to means of transport, used in real transport systems, it has been found that these damages are the effect of different forcing factors. A certain number of damages is caused by natural wear of machine elements, whereas other damages can occur in result of ineffective repair of a previous damage. Thus, the so called recurrent (secondary) damages occur in a short period of time. On the basis of literature and maintenance and operation analysis results it was found that the most frequent cause of recurrent damage occurrence is improper quality of repairs of the analyzed means of transport. Primary damages are not dependent on each other and they appear randomly, whereas recurrent damages do depend on each other and their occurrence is the conditioned by earlier occurrence of a repair, and above all, by its poor quality. In the paper, a method for evaluation the influence of carried out repairs on transport means operational reliability, has been presented On the basis of the analysis of the moments in which damages to the means of transport and of the time interval lengths between them a simulation model representing a real stream of the damages was built, which enables to evaluate influence of the efficiency of the performed repairs of the means of transport in the real transport system

scholarly journals Longitudinal study of fingerprint recognition

2015 ◽  
Vol 112 (28) ◽  
pp. 8555-8560 ◽  
Author(s):  
Soweon Yoon ◽  
Anil K. Jain
Keyword(s):  
Statistical Models ◽  
Recognition Accuracy ◽  
Temporal Stability ◽  
Poor Quality ◽  
Time Span ◽  
Fingerprint Recognition ◽  
Time Interval ◽  
General Belief ◽  
Probability Of Error ◽  
Fingerprint Database

Human identification by fingerprints is based on the fundamental premise that ridge patterns from distinct fingers are different (uniqueness) and a fingerprint pattern does not change over time (persistence). Although the uniqueness of fingerprints has been investigated by developing statistical models to estimate the probability of error in comparing two random samples of fingerprints, the persistence of fingerprints has remained a general belief based on only a few case studies. In this study, fingerprint match (similarity) scores are analyzed by multilevel statistical models with covariates such as time interval between two fingerprints in comparison, subject’s age, and fingerprint image quality. Longitudinal fingerprint records of 15,597 subjects are sampled from an operational fingerprint database such that each individual has at least five 10-print records over a minimum time span of 5 y. In regard to the persistence of fingerprints, the longitudinal analysis on a single (right index) finger demonstrates that (i) genuine match scores tend to significantly decrease when time interval between two fingerprints in comparison increases, whereas the change in impostor match scores is negligible; and (ii) fingerprint recognition accuracy at operational settings, nevertheless, tends to be stable as the time interval increases up to 12 y, the maximum time span in the dataset. However, the uncertainty of temporal stability of fingerprint recognition accuracy becomes substantially large if either of the two fingerprints being compared is of poor quality. The conclusions drawn from 10-finger fusion analysis coincide with the conclusions from single-finger analysis.

scholarly journals Statistical and Evolutionary Aspects of Cometary Orbits

1989 ◽  
Vol 116 (1) ◽  
pp. 487-535
Author(s):  
J.A. Fernández ◽  
W.-H. Ip
Keyword(s):  
Molecular Clouds ◽  
Oort Cloud ◽  
Tidal Force ◽  
Time Interval ◽  
Mass Relation ◽  
Galactic Latitude ◽  
Impact Cratering ◽  
Influx Rate ◽  
Short Period ◽  
The Impact

AbstractThe observed frequency of passages of Earth-crossing long-period (LP) comets (P > 200 yr) is about three per year for comets brighter than absolute magnitude H10 ∼ 10.5. About one out of six LP comets is estimated to be new, i.e., making its first passage through the inner planetary region. The sample of observed LP comets shows an excess of retrograde orbits that may be accounted for by the shorter dynamical lifetimes of comets on direct orbits due to planetary perturbations. The original semimajor axes of new comets concentrate in the range 7 × 103 ≳ aorig ≳ 4 × 104 AU, which tells us about the region of the Oort cloud where forces other than planetary perturbations act with the greatest efficiency. Yet the distribution of original semimajor axes cannot tell us anything about the existence of a dense inner core of the Oort cloud. Besides planetary perturbations, passing stars, molecular clouds and the galactic tidal force also influence the dynamical evolution of Oort cloud comets. The observed distribution of the aphelion points of near-parabolic comets shows such a dependence on the galactic latitude. Molecular clouds and stars penetrating very deeply in the Oort cloud are found to give rise to major enhancements in the influx rate of new comets, known as comet showers, at average intervals of a few 107 yr.An important issue to solve concerns how the frequency of comet passages varies with time, in particular as regards to the current level of comet appearances. Should we be passing through a highly intense phase, most aphelia of the incoming Oort comets would concentrate on the sky area where the strong perturber exerted its greatest effect. By contrast, the observed galactic latitude dependence of the aphelia suggests a dominant influence of the vertical galactic tidal force as compared with random strong perturbers. This seems to indicate that the frequency of comet passages is currently at, or near, its quiescent level. Whether intense comet showers are reflected in the impact cratering record is still a debatable issue. A periodicity of ∼ 26-30 Myr in the impact cratering rate is quite uncertain, owing to the small size of the sample of well-dated craters and the noise from background impact craters from asteroids.The family of short-period (SP) comets (orbital periods P < 20 yr) has long been regarded as the dynamical end-state of new comets on low-inclination orbits captured by Jupiter. However, if SP comets came from a spherical population of comets (e.g., incoming new comets), we should expect to find a percentage of them on retrograde orbits, which contradicts the observations. An alternative hypothesis for the origin of most SP comets is that they come from a trans-Neptunian comet belt. Extensive searches aimed at detecting faint slow-moving objects are required to assess the size of the comet population in the outer planetary region. Modeling of the transfer rate of comets from an outer belt to SP orbits gives transient populations between Saturn and Neptune on the order of 106 – 107 bodies. This is roughly comparable to the upper limit set by the most recent searches of outer solar system bodies.The impact crater production rate of comets, at the present time, can be estimated to be on the order of 10% of the value corresponding to asteroidal impacts. These estimates, however, are subject to large uncertainties in the brightness-mass relation of comets and crater scaling law. The Earth could have received about 2 × 1020 g of cometary material over the last 4 billion years — if the injection rate of new comets remained constant in the time interval. Within the context of H2O inventory, the cometary influx should have rather minor effects. On the other hand, because of the paucity of H2O content in the atmospheres of Venus and Mars, cometary impact could strongly modulate their water contents.

scholarly journals Analysis of voltage and current magnification in resonant circuits on hyperspectral signal processing

2020 ◽  
Vol 53 (3-4) ◽  
pp. 635-648 ◽  
Author(s):  
Arumuga Maria Devi Thanu ◽  
Muthukumar Devadoss ◽  
Kumar Parasuraman
Keyword(s):  
Signal Processing ◽  
Power Quality ◽  
Poor Quality ◽  
Control Measures ◽  
Quality Analysis ◽  
Nonlinear Loads ◽  
Magnetic Attraction ◽  
Short Period ◽  
Rlc Circuits

In the recent years, electrical, electronics, and telecommunications have far-famed a rare improvement, the quantity of nonlinear loads has inflated. Many electric power consumption devices are sensitive to magnetic attraction disturbances, created through nearby devices, which might have an effect on the power quality for several industry units or may be domestic users. Poor quality of power leads to fault of devices and instrumentation instability in a short period. Systematically, some research and analysis are required to monitor the disturbances of power quality which increases quality of power. This paper consists of power quality analysis on RLC circuits with voltage and current magnification values through Hyperspectral signal processing. The voltage changes and harmonic disturbances can be simulated finely with the MATLAB–Simulink simulation results and the theoretical analysis display. The simulated outcome and the Hyperspectral processing offer data and identification of power quality variances and additional control measures accurately.

Freeze-induced reduction of broccoli yield and quality

1999 ◽  
Vol 39 (6) ◽  
pp. 771 ◽  
Author(s):  
D. K. Y. Tan ◽  
D. C. Joyce ◽  
A. H. Wearing ◽  
K. G. Rickert ◽  
C. J. Birch
Keyword(s):  
Poor Quality ◽  
Freezing Injury ◽  
Yield Reduction ◽  
Lethal Temperature ◽  
Shoot Apices ◽  
Yield And Quality ◽  
Temperature Regimes ◽  
Short Period ◽  
Crop Development ◽  
Whole Plants

Summary. Sub-zero temperatures can result in freezing injury of broccoli (Brassica oleracea L. var. italica Plenck) plants and thereby reduce head yield and quality. In order to predict effects of frosts, it is desirable to know the stages of development at which broccoli plants are most susceptible to freezing injury. In this study, the effect of a range of sub-zero temperatures for a short period at different stages of crop development were assessed and quantified in terms of mortality, yield and quality of broccoli. Whole plants in pots or in the field were subjected to sub-zero temperature regimes from –1 to –19°C. Extracellular ice formation was achieved by reducing temperatures slowly, at –2°C per hour. The floral initiation stage was most sensitive to freezing injury, as yields (fresh and dry head weights) were significantly reduced at –1 and –3°C, and the shoot apices were killed at –5°C. There was no significant yield reduction when the inflorescence buttoning stage was treated at –1 and –3°C. Although shoot apices survived the –5°C treatment at buttoning, very poor quality heads of uneven bud size were produced as a result of arrested development. The lethal temperature for pot-grown broccoli was between –3 and –5°C, whereas the lethal temperature for field-grown broccoli was between –7 and –9°C. The difference was presumably due to variation in cold acclimation. Freezing injury can reduce broccoli head yield and quality and retard plant growth. With regard to yield and maturity prediction, crop development models based only on simple thermal time without restrictions will not apply if broccoli crops are frost damaged.

scholarly journals The Evolution of Jupiter Family Comets over 2000 Years

1992 ◽  
Vol 152 ◽  
pp. 269-274 ◽  
Author(s):  
G. Tancredi ◽  
H. Rickman
Keyword(s):  
Data Base ◽  
Orbital Evolution ◽  
Physical Parameters ◽  
Time Interval ◽  
Orbital Elements ◽  
Present Epoch ◽  
Numerical Integrations ◽  
Short Period

The orbital evolution of the whole sample sample of short-period comets was computed by numerical integrations for a time interval of 2000 yr centered on the present epoch. This data base is intended to serve in various studies involving the statistics of orbital evolution and correlation with physical parameters or discovery circumstances. We present some results concerning the following aspects: the evolution of the orbital elements and their past-future asymmetry, statistics on the discovery of comets and on the encounters of comets with Jupiter.

scholarly journals Analysis of assessment criteria for selected systems of transport means operation

2018 ◽  
Vol 182 ◽  
pp. 02003
Author(s):  
Łukasz Muślewski ◽  
Leszek Knopik ◽  
Bogdan Landowski ◽  
Oleh Polishchuk
Keyword(s):  
Time Moment ◽  
Transport Systems ◽  
Time Interval ◽  
Sociotechnical System ◽  
Human Driver ◽  
System Functioning ◽  
Technical Systems

The problems discussed in the study are connected with evaluation of complex technical systems functioning, in particular, transport systems. It was assumed that evaluation of their functioning depends on fulfilment degree of selected criteria. Therefore, it is important to determine a set of criteria including their type, number and importance. Since the research object is a public city transport system considered to be a sociotechnical system of the type: human (driver) –machine (vehicle) and the environment <H-M-E>, the criteria to be used for the assessment must include behavior of humans, operation of transport means, and the environmental impact. Thus, selection and determination of importance of significant, time variable, measurable and independent characteristics whose values, in a given time moment or a given time interval, define fulfillment degree of the criteria provide the basis for evaluation of such systems functioning. The quality of technical systems functioning in time is assessed on the basis of the criteria fulfilment degree or comparison and classification of different systems of the same type. It needs to be emphasized that the choice of optimal methods for selection of relevant criteria and determination of their impact on the analyzed system functioning is the research subject of study.

Approach to Risk Management for the Hydrocarbon-Transport Infrastructure With Regard to Climate Change

2015 ◽  
Author(s):  
Dario Zapata Posada ◽  
Jaime Hernán Aristizábal Ceballos ◽  
Julián Fernando Chaves Agudelo ◽  
Milton Eduardo Pardo Romero
Keyword(s):  
Climate Change ◽  
Risk Management ◽  
National Development ◽  
Climatic Changes ◽  
Transport Infrastructure ◽  
Climatic Variables ◽  
Transport Systems ◽  
Extreme Weather Events ◽  
Short Period ◽  
Hydrocarbon Transport

Planet Earth has recently witnessed a change in the behavior of climate variables (including temperature, rainfall, etc.), primarily attributed to global warming. This climate change is a threat that is materializing and has affected elements of the infrastructure, ecosystems, and environmental conditions worldwide, as well as the National Development Plans [“Planes Nacionales de Desarrollo”]. The hydrocarbon-transport infrastructure in Colombia has not escaped the effects of climate variability. Therefore, a strategy must be devised to manage the risk and to adapt these systems in the light of potential harmful effects, and also to supplement or improve the mitigation measures for the effects generated by the oil industry through its operations. Climate disturbances lead to an increase in the likelihood of landslides, wildfires, floods, avalanches, and other natural hazards. The major climate changes that have been identified and that may affect hydrocarbon-transfer systems in Colombia are the following ones: • A gradual increase in temperature. • Changes in the patterns and amounts of rainfall. • A rise in sea level. • An increase in the severity and frequency of extreme weather events. The strategy for adapting the hydrocarbon-transport systems in light of climate change focuses primarily on the following points: 1. Acquiring more knowledge about the climatic changes that are expected to occur in Colombia, including the change in the major climatic variables and their georeferencing. 2. Diagnosing the transport systems and their spatial correlation with future climate scenarios. 3. Identifying the industries or elements of the infrastructure that are most vulnerable to the expected climatic changes. 4. Proposing measures that will add strength and/or resilience, so that the elements of the system can resist the effects of climate change, or overcome them within a short period of time, without affecting the Business. 5. Prioritizing the interventions to be performed at sites that are critical to the Business. 6. Monitoring and tracking the climatic variables in order to adjust the susceptibility models in light of the major impacts (e.g., landslides). The primary goal of this paper is to outline the initiative that has been proposed by the Technical Asset Management Bureau [“Gerencia Técnica de Activos”] (GTA) of Ecopetrol’s Office of the Vice President for Transportation and Logistics [“Vicepresidencia de Transporte y Logística”] (VIT Ecopetrol) in order to adapt the currently operating transport systems so that they can deal with climate change, while ensuring their healthful and safe operation, in compliance with the applicable technical legal requirements. Another goal of this paper is to highlight the advances that have been made by the GTA in the procurement, compilation, analysis, and use of climate information and geotechnical data as basic elements of risk management.

Abrupt shrinking of solar corona in late 1990s and related changes in solar magnetic structure

2020 ◽  
Author(s):  
Kalevi Mursula ◽  
Ilpo Virtanen ◽  
Jennimari Koskela ◽  
Ismo Tähtinen
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Solar Corona ◽  
Coronal Magnetic Field ◽  
Systematic Change ◽  
Time Interval ◽  
Source Surface ◽  
Abrupt Decrease ◽  
Heliospheric Magnetic Field ◽  
Short Period

&lt;p&gt;Several studies have noted on changes in the properties of sunspots, and in the mutual relations between various global parameters of solar magnetic activity (e.g. UV/EUV irradiance, radio and IR emissions, TSI/SSI), as well as between solar and ionospheric parameters since the onset of solar cycle 23. These changes have been suggested to be related to the overall reduction of solar activity at the aftermath of the decline of the Grand modern maximum of solar activity that prevailed during most of the 20th century. We have recently derived the longest record of coronal magnetic field intensities since 1968 using Mount Wilson Observatory and Wilcox Solar Observatory observations of the photospheric magnetic field and the PFSS model, and compared it with the heliospheric magnetic field observed at the Earth. We found that the time evolution of the coronal magnetic field during the last 50 years agrees with the heliospheric magnetic field only if the effective coronal size, the distance of the coronal source surface of the heliospheric magnetic field, is allowed to change in time. We calculated the optimum distance for each solar rotation and found that it experienced an abrupt decrease in the late 1990s. The effective volume of the solar corona shrunk to less than one half of its previous value during a short period of only a few years. This shrinking was related with a systematic change in the structure of the coronal magnetic field during the same time interval. We review these dramatic changes in the solar corona and discuss their possible connection to the changes in the different solar activity parameters and the reduction of the overall solar activity.&lt;/p&gt;

The population dynamics of Gyrodactylus bullatarudis (Monogenea) within laboratory populations of the fish host Poecilia reticulata

Parasitology ◽  
1984 ◽  
Vol 89 (1) ◽  
pp. 159-194 ◽  
Author(s):  
Marilyn E. Scott ◽  
R. M. Anderson
Keyword(s):  
Poecilia Reticulata ◽  
Acquired Resistance ◽  
Parasite Burden ◽  
Fish Host ◽  
Time Interval ◽  
Helminth Parasites ◽  
Short Period ◽  
Laboratory Populations ◽  
Host Mortality ◽  
Transmission Stage

SummaryExperiments were undertaken to investigate the factors which influence the transmission dynamics of Gyrodactylus bullatarudis within populations of laboratory guppies. The parasites possess a number of biological attributes which are almost unique amongst helminth parasites of vertebrates. These include the ability to reproduce viviparously and directly on the surface of the host, the ability to survive death of the host (for a short period of time) and the ability to transfer between hosts (despite the absence of a specialized transmission stage in the parasite's life-cycle). Long-term laboratory experiments demonstrated the inability of the parasite to persist within populations of the host in the absence of the continual introduction of naive susceptible fish. With regular addition of susceptible fish, the parasite population exhibited recurrent epidemic behaviour. The magnitudes of the epidemics and the time interval between them, were dependent on the rate at which fish were added to the populations. The parasite was over-dispersed in its distribution within the experimental fish populations and was a significant cause of host mortality (in a manner related to parasite burden). The experimental results suggest that acquired resistance to infection is an important factor determining epidemic behaviour.

scholarly journals Intelligent Model of Potential Risks in Emergence of Man-Made Disaster

2020 ◽  
Vol 19 (5) ◽  
pp. 437-448
Author(s):  
A. V. Gulay ◽  
V. M. Zaitsev
Keyword(s):  
Management System ◽  
Control Point ◽  
Probabilistic Methods ◽  
Time Interval ◽  
Structural Level ◽  
Technical Object ◽  
Material Loss ◽  
Potential Risks ◽  
Quantitative Indicators ◽  
Intelligent Model

A man-made catastrophe is considered as an information display of catastrophic development of events in the management system, a peculiar projection of  a man-made catastrophe on the information plane. The paper presents an intellectual model, considers dynamics and ranges of emergency changes in management system parameters, assesses potential risks and  threats  of  catastrophe  emergence.  It  has been  shown  that  at  the  macro-structural  level  for  semantic   description of a catastrophe, it is quite effective to use a tree-like network of scenarios, which displays the conceptual scheme of the subject and problem areas of the catastrophe and is based on judgments of experts, their experience and intuition. This allows probabilistic methods  to  assess  potential  risks  of  a catastrophe using two quantitative indicators: risk (probability) level of  phenomenon occurrence at a certain control point of time and the volume of the expected material loss. It has been suggested that for assessment of possible microstate the fuzzy logic should be applied for each critical object parameter, tolerance limits and functions of affiliation with the fields of fail-safe object functioning should be set by expertise, migration trajectories of relative parameter values should be monitored and terms of their forced return to the working field of regular functioning should be duly provided. Quantitative indicators having imprecise origin have been introduced in the intelligent model of potential risks to assess dynamics of catastrophe threat. One of these indicators is the expert level of catastrophe occurrence during migration of a group of abnormally dangerous parameters of a technical object. The time interval has also been considered which is measured from the current moment to the expected moment of catastrophe occurrence at the preset maximum permissible level of catastrophe threat.

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