scholarly journals AIR TRANSPORT IN GHANA: SOME CLIMATIC CONSTRAINTS

Aviation ◽  
2012 ◽  
Vol 16 (3) ◽  
pp. 88-95 ◽  
Author(s):  
Abdul-Wadood Moomen
Keyword(s):  
Weather Conditions ◽  
Climatic Conditions ◽  
Air Transport ◽  
Transport Systems ◽  
Aviation Industry ◽  
Air Turbulence ◽  
Transportation Sector ◽  
Adverse Weather ◽  
Climatic Constraints ◽  
The Impact

Understanding a definite geographic context is essential for effective air transport management. To date, the consequences of changing weather conditions and climate on the transportation sector in Ghana has been grievous to the economy of the country. Unfortunately, the impact of climate change on the aviation industry has received very little attention in Ghanaian literature. Meanwhile, it is widely known that transport systems on the whole perform poorly under adverse weather and climatic conditions. This paper seeks to reflect a growing orientation in research and philosophy in the field of air transport and severe weather and climatic constraints. Understanding under-lying principles of climatic conditions and weather is essential to air navigation in Ghana. Clear air turbulence, ceiling and visibility, thunderstorms, electrical phenomenon, climate-induced seasonal variations, and vegetation are some of the threats to air transport across Ghana's airspace. Information is derived from literature surveys, workplace counts, and an aviation researcher. Overall, large information technology investments, consolidation, and re-structuring are all major issues that must be addressed by stakeholders ambitious to stay afloat and competitive in Ghana's airspace.

Modelling of 10 Gbps Free Space Optics Communication Link Using Array of Receivers in Moderate and Harsh Weather Conditions

2017 ◽  
Vol 38 (3) ◽  
Author(s):  
Amit Gupta ◽  
Nagpal Shaina
Keyword(s):  
Free Space ◽  
Weather Conditions ◽  
Quality Data ◽  
Laser Source ◽  
Communication Link ◽  
Free Space Optical ◽  
Space Optics ◽  
Received Power ◽  
Adverse Weather ◽  
The Impact

AbstractIntersymbol interference and attenuation of signal are two major parameters affecting the quality of transmission in Free Space Optical (FSO) Communication link. In this paper, the impact of these parameters on FSO communication link is analysed for delivering high-quality data transmission. The performance of the link is investigated under the influence of amplifier in the link. The performance parameters of the link like minimum bit error rate, received signal power and Quality factor are examined by employing erbium-doped fibre amplifier in the link. The effects of amplifier are visualized with the amount of received power. Further, the link is simulated for moderate weather conditions at various attenuation levels on transmitted signal. Finally, the designed link is analysed in adverse weather conditions by using high-power laser source for optimum performance.

Comparison of two gap-filling techniques for nitrous oxide fluxes from agricultural soil

2019 ◽  
Vol 99 (1) ◽  
pp. 12-24 ◽  
Author(s):  
Rezvan Taki ◽  
Claudia Wagner-Riddle ◽  
Gary Parkin ◽  
Rob Gordon ◽  
Andrew VanderZaag
Keyword(s):  
Missing Values ◽  
Interpolation Method ◽  
Weather Conditions ◽  
Linear Interpolation ◽  
Bias Error ◽  
Research Station ◽  
Ann Model ◽  
Gap Filling ◽  
Adverse Weather ◽  
The Impact

Micrometeorological methods are ideally suited for continuous measurements of N2O fluxes, but gaps in the time series occur due to low-turbulence conditions, power failures, and adverse weather conditions. Two gap-filling methods including linear interpolation and artificial neural networks (ANN) were utilized to reconstruct missing N2O flux data from a corn–soybean–wheat rotation and evaluate the impact on annual N2O emissions from 2001 to 2006 at the Elora Research Station, ON, Canada. The single-year ANN method is recommended because this method captured flux variability better than the linear interpolation method (average R2 of 0.41 vs. 0.34). Annual N2O emission and annual bias resulting from linear and single-year ANN were compatible with each other when there were few and short gaps (i.e., percentage of missing values <30%). However, with longer gaps (>20 d), the bias error in annual fluxes varied between 0.082 and 0.344 kg N2O-N ha−1 for linear and 0.069 and 0.109 kg N2O-N ha−1 for single-year ANN. Hence, the single-year ANN with lower annual bias and stable approach over various years is recommended, if the appropriate driving inputs (i.e., soil temperature, soil water content, precipitation, N mineral content, and snow depth) needed for the ANN model are available.

scholarly journals THE INFLUENCE OF CLIMATE ON THE RESPIRATORY FUNCTION OF THE HEALTHY POPULATION OF VLADIVOSTOK AND PATIENTS WITH BRONCHOPULMONARY PATHOLOGY

2018 ◽  
Vol 97 (5) ◽  
pp. 418-423
Author(s):  
L. V. Veremchuk ◽  
E. E. Mineeva ◽  
Tatyana I. Vitkina ◽  
T. A. Gvozdenko
Keyword(s):  
Respiratory Function ◽  
Pulmonary Ventilation ◽  
Weather Conditions ◽  
Climatic Conditions ◽  
Bronchial Obstruction ◽  
Healthy Population ◽  
Uncontrolled Asthma ◽  
Monsoon Climate ◽  
Climatic Impact ◽  
The Impact

Introduction. The climatic factors affect the mucous membrane of the respiratory tract contacting with the environment. The investigation of pulmonary ventilation plays a leading role in the diagnosis of bronchial obstruction in response to an external stimulus. Material and methods. The study included a healthy population of the city and patients with chronic catarrhal nonobstructive bronchitis (CCNB), controlled and uncontrolled asthma (131 people). The respiratory function (RF) was estimated by spirography and body plethysmography. Meteorological conditions were evaluated from the point of view of contrasting weather changes (on the survey day, on 1st and 2nd days before the survey). The degree of the climatic impact on RF was determined by the statistical module “Discriminant analysis”, used to a group of RF indices relatively adverse levels of impact of the monsoon climate. Results. The low level of the responsiveness in a healthy urban population was identified. The negative impact of climatic indices on the respiratory system in CCNB patients was observed mainly in extreme weather conditions. The influence of climatic conditions on patients with asthma depends on the level of the disease control. Discussion. The influence of climatic conditions was found to be within the adaptive and compensatory responses in a group of healthy people and CCNB patients. We assumed the use of basic drugs in patients with asthma without signs of bronchial obstruction to reduce the susceptibility of the receptors of the bronchi to the negative climatic impact. The greatest negative RF response to the impact of monsoon climate manifested both in static and in dynamic weather conditions, was observed in patients with uncontrolled asthma. It was associated with the impaired pulmonary ventilation. Conclusion. The results indicate the Far East monsoon climate to be an important risk factor for the exacerbation in patients with respiratory diseases.

scholarly journals An Advanced Deep Learning Approach for Multi-Object Counting in Urban Vehicular Environments

2021 ◽  
Vol 13 (12) ◽  
pp. 306
Author(s):  
Ahmed Dirir ◽  
Henry Ignatious ◽  
Hesham Elsayed ◽  
Manzoor Khan ◽  
Mohammed Adib ◽  
...  
Keyword(s):  
Deep Learning ◽  
Intelligent Transportation Systems ◽  
Smart Cities ◽  
Weather Conditions ◽  
Research Area ◽  
Transportation Systems ◽  
Detection Accuracy ◽  
Adverse Weather ◽  
Object Counting ◽  
The Impact

Object counting is an active research area that gained more attention in the past few years. In smart cities, vehicle counting plays a crucial role in urban planning and management of the Intelligent Transportation Systems (ITS). Several approaches have been proposed in the literature to address this problem. However, the resulting detection accuracy is still not adequate. This paper proposes an efficient approach that uses deep learning concepts and correlation filters for multi-object counting and tracking. The performance of the proposed system is evaluated using a dataset consisting of 16 videos with different features to examine the impact of object density, image quality, angle of view, and speed of motion towards system accuracy. Performance evaluation exhibits promising results in normal traffic scenarios and adverse weather conditions. Moreover, the proposed approach outperforms the performance of two recent approaches from the literature.

scholarly journals Regional assessment of climate risks using GIS technologies (on the example of the Belgorod Region)

2020 ◽  
Vol 26 (1) ◽  
pp. 271-278
Author(s):  
Yuri Chendev ◽  
Maria Lebedeva ◽  
Olga Krymskaya ◽  
Maria Petina
Keyword(s):  
Climate Change ◽  
Quantitative Assessment ◽  
Weather Conditions ◽  
Climatic Conditions ◽  
Winter Period ◽  
Adaptation Measures ◽  
Climate Services ◽  
Climate Risks ◽  
Weather And Climate ◽  
The Impact

The ongoing climate change requires a quantitative assessment of the impact of weather conditions on the nature and livelihoods of the population. However, to date, the concept of “climate risk” has not been finally defined, and the corresponding terminology is not universally recognized. One manifestation of climate change is an increase in climate variability and extremeness in many regions. At the same time, modern statistics indicate growing worldwide damage from dangerous weather and climate events. The most widely used in climate services is the concept of “Vulnerability index”, which reflects a combination (with or without weighing) of several indicators that indicate the potential damage that climate change can cause to a particular sector of the economy. development of adaptation measures to ensure sustainable development of territories. The main criterion for the vulnerability of the territory from the point of view of meteorological parameters is the extremeness of the basic values: daily air temperature, daily precipitation, maximum wind speed. To fully take into account the possible impacts of extreme climatic conditions on the region’s economy, it is necessary to detail the weather and climate risks taking into account the entire observation network, since significant differences in quantitative assessment are possible. The obtained average regional values of the climate vulnerability indices for the Belgorod Region of the Russian Federation provide 150 points for the winter period, 330 points for the summer season, which indicates the prevalence of extreme weather conditions in the warm season. Most of the territory has a relative influence on climatic phenomena, with the exception of the East and the Southeast Region. Moreover, the eastern part of the region is the most vulnerable in climatic terms.

Investigating the Impact of Rainfall on Travel Speed

2014 ◽  
Vol 71 (3) ◽  
Author(s):  
Nordiana Mashros ◽  
Johnnie Ben-Edigbe ◽  
Hashim Mohammed Alhassan ◽  
Sitti Asmah Hassan
Keyword(s):  
Empirical Studies ◽  
Heavy Rain ◽  
Weather Conditions ◽  
Travel Speed ◽  
Operating Conditions ◽  
Speed Reduction ◽  
Light Rain ◽  
Rainfall Condition ◽  
Adverse Weather ◽  
The Impact

The road network is particularly susceptible to adverse weather with a range of impacts when different weather conditions are experienced. Adverse weather often leads to decreases in traffic speed and subsequently affects the service levels. The paper is aimed at investigating the impact of rainfall on travel speed and quantifying the extent to which travel speed reduction occurs. Empirical studies were conducted on principle road in Terengganu and Johor, respectively for three months. Traffic data were collected by way of automatic traffic counter and rainfall data from the nearest raingauge station were supplied by the Department of Irrigation and Drainage supplemented by local survey data. These data were filtered to obtain traffic flow information for both dry and wet operating conditions and then were analyzed to see the effect of rainfall on percentile speeds. The results indicated that travel speed at 15th, 50th and 85th percentiles decrease with increasing rainfall intensities. It was observed that allpercentile speeds decreased from a minimum of 1% during light rain to a maximum of 14% during heavy rain. Based on the hypothesis that travel speed differ significantly between dry and rainfall condition; the study found substantial changes in percentile speeds and concluded that rainfalls irrespective of their intensities have significant impact on the travel speed.

Effectiveness of Predictive Weather-Related Active Transportation and Demand Management Strategies for Network Management

2017 ◽  
Vol 2667 (1) ◽  
pp. 71-87 ◽  
Author(s):  
Zihan Hong ◽  
Hani S. Mahmassani ◽  
Xiang Xu ◽  
Archak Mittal ◽  
Ying Chen ◽  
...  
Keyword(s):  
Traffic Management ◽  
Demand Management ◽  
Management Strategies ◽  
Weather Conditions ◽  
Active Transportation ◽  
Operational Conditions ◽  
Traffic Conditions ◽  
Adverse Weather ◽  
Traffic Performance ◽  
The Impact

This paper presents the development, implementation, and evaluation of predictive active transportation and demand management (ATDM) and weather-responsive traffic management (WRTM) strategies to support operations for weather-affected traffic conditions with traffic estimation and prediction system models. First, the problem is defined as a dynamic process of traffic system evolution under the impact of operational conditions and management strategies (interventions). A list of research questions to be addressed is provided. Second, a systematic framework for implementing and evaluating predictive weather-related ATDM strategies is illustrated. The framework consists of an offline model that simulates and evaluates the traffic operations and an online model that predicts traffic conditions and transits information to the offline model to generate or adjust traffic management strategies. Next, the detailed description and the logic design of ATDM and WRTM strategies to be evaluated are proposed. To determine effectiveness, the selection of strategy combination and sensitivity of operational features are assessed with a series of experiments implemented with a locally calibrated network in the Chicago, Illinois, area. The analysis results confirm the models’ ability to replicate observed traffic patterns and to evaluate the system performance across operational conditions. The results confirm the effectiveness of the predictive strategies tested in managing and improving traffic performance under adverse weather conditions. The results also verify that, with the appropriate operational settings and synergistic combination of strategies, weather-related ATDM strategies can generate maximal effectiveness to improve traffic performance.

scholarly journals Determinants of financial distress in the European air transport industry: The moderating effect of being a flag-carrier

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259149
Author(s):  
Yin Shi ◽  
Xiaoni Li
Keyword(s):  
Financial Distress ◽  
Financial Stability ◽  
Negative Influence ◽  
Air Transport ◽  
Transport Sector ◽  
Aviation Industry ◽  
Air Transport Industry ◽  
Low Efficiency ◽  
And Performance ◽  
The Impact

Due to the COVID-induced global collapse in demand for air travel, the year 2020 was a catastrophic one for the aviation industry. A dramatic drop in operating revenues along with continuing fixed expenses drained the cash reserves of airlines, with consequent risks of financial distress and, potentially, even of bankruptcy. Flag-carriers are a special group in the airline business—they are considered to have privileges in terms of the support given by governments while, on the other hand, are often viewed as having low efficiency and performance. This study aims to estimate for European airlines the interaction effect of being a flag-carrier (flagship) with the relationship between leverage, liquidity, profitability, and the degree of financial distress. Findings obtained from analysing 99 European airlines over a period of ten years, indicate that the negative influence of leverage on financial stability is higher in the case of flag carriers (flagship). The impact of liquidity and profitability on financial health is more positive for flagship than for non-flagship carriers. These findings are not limited to contributing to the existing literature, but also have significant practical implications for executives, managers, and policy makers in the European air transport sector.

scholarly journals Cardiovascular risk assessment of the population under adverse weather conditions

2020 ◽  
Vol 99 (5) ◽  
pp. 488-492
Author(s):  
R. B. Tsallagova ◽  
O. I. Kopytenkova ◽  
Fatima K. Makoeva ◽  
A. R. Nanieva
Keyword(s):  
Negative Impact ◽  
Adult Population ◽  
Medical Science ◽  
Weather Conditions ◽  
Air Pressure ◽  
Medical Documentation ◽  
Atmospheric Air ◽  
Adverse Weather ◽  
The Impact ◽  
The City

Introduction. Climate change around the world determines the relevance of the study of its effects on the human health. Nowadays, due to the development of modern medical science, the methods of evidence-based analysis of negative impact of the environmental factors on the public health are being widely implemented into preventive medicine. Their use should make it possible to quantify the various risks with high confidence and to manage them effectively. Material and methods. The weather conditions of the territory of Vladikavkaz for a 15-years period (2001-2015) have been studied. On the basis of the data from the primary medical documentation of emergency medical care (EMC) for the same period, the health status of the adult population in the city has been studied. The impact of the meteorological elements under the study on the frequency of seeking EMC was estimated using the relative (RR) and population risks (Rpop) values. Results. For the city of Vladikavkaz (according to the medical classification of weather conditions), high air humidity is typical for 65% of the days in a year, low air velocity (less than 3 m/s) - 77% of the days in a year. Inter-day fluctuations in temperature and atmospheric air pressure, exceeding the optimal levels for the human body, are recorded more than in 30% of the days in a year. Discussion. The city of Vladikavkaz is characterized by windless, wet weather, with frequent inter-day fluctuations in temperature and atmospheric air pressure, which corresponds to the clinically irritating and acute types of weather. Conclusion. The calculations of the relative and the population risks of impact of meteorological changes on the developing of urgent cardiovascular conditions in the population of Vladikavkaz showed RR of combining two unfavourable weather factors to be of 1.081 (p <0.0001), and the Rpop increases by more than 3600 additional EMC calls due to cardiovascular pathology.

scholarly journals MATHEMATICAL MODEL OF IMPLEMENTATION OF FIRE TASKS BY TANK CREW ON THE BATTLEFIELD

2020 ◽  
Vol 2 (36) ◽  
pp. 63-69
Author(s):  
D. Khaustov ◽  
◽  
Ya. Khaustov ◽  
V. Sokolovskij ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Markov Chain ◽  
Full Range ◽  
Weather Conditions ◽  
Observation System ◽  
Extended Model ◽  
Sequence Of Events ◽  
Functional Scheme ◽  
Adverse Weather ◽  
The Impact

Reconnaissance and defeat of enemy targets on the battlefield depends on the technical characteristics of surveillance and sighting devices, and it is important to ensure their effective operation, during both the day and night, especially in adverse weather conditions. Therefore, in the field of modernization and development of surveillance and sighting devices, by both domestic and foreign manufacturers, in recent years there has been a major trend towards the development of multi-channel sighting systems on armored vehicles. To determine the optimal parameters of the sighting systems of armored vehicle samples, it is necessary to develop a mathematical model that would take into account the entire process of target reconnaissance, including the impact of full range of natural and man-made obstacles, to determine the ways for the improvement of combat effectiveness of weapons samples. In this work, a mathematical model is developed for description of fire tasks execution on the battlefield by a tank crew, which is equipped with a multi-channel sight-monitoring system, to assess the work of the sighting system as whole as well as of each of its channels. The analysis of the functional scheme of solving the combat task shows that the stage of data acquisition should be divided into, at least three, separate states, namely: detection, recognition and identification such that the transitions between these states will be described by the corresponding probabilities. The developed model describes the sequence of events that in terms of probability theory form a Markov chain. The proposed analytical Markov model allows for modeling the solution of fire tasks by the tank crew equipped with a multi-channel sighting and observation system with separate consideration of the stages of target reconnaissance, its recognition and identification, which in turn are considered as separate states of the Markov chain. The model opens a possibility for the development of an extended model to determine a quantitative indicator to assess the effectiveness of a given sighting system in comparison with its analogs.

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