scholarly journals Reliability Analysis of an Air Traffic Network: From Network Structure to Transport Function

2020 ◽  
Vol 10 (9) ◽  
pp. 3168 ◽  
Author(s):  
Shanmei Li ◽  
Zhaoyue Zhang ◽  
Xiaochun Cheng
Keyword(s):  
Network Reliability ◽  
Evaluation Model ◽  
Air Traffic ◽  
Transformation Model ◽  
Traffic Network ◽  
Traffic Networks ◽  
Travel Time Reliability ◽  
Factors Affecting ◽  
The Us ◽  
Overall Reliability

To scientifically evaluate the reliability of air traffic networks, a definition of air traffic network reliability is proposed in this paper. Calculation models of the connectivity reliability, travel-time reliability, and capacity reliability of the air traffic network are constructed based on collected historical data, considering the current status and the predicted future evolution trends. Considering the randomness and fuzziness of factors affecting reliability, a comprehensive evaluation model of air traffic networks based on the uncertainty transformation model is established. Finally, the reliability of the US air traffic network is analyzed based on data published by the Transportation Statistics Bureau of the US Department of Transportation. The results show that the connectivity reliability is 0.4073, the capacity reliability is 0.8300, the travel-time reliability is 0.9180, and the overall reliability evaluated is “relatively reliable”. This indicates that although the US structural reliability is relatively low, the US air traffic management is very efficient, and the overall reliability is strong. The reliability in nonpeak hours is much higher than that in peak hours. The method can identify air traffic network reliability efficiently. The main factors affecting reliability can be found in the calculation process, and are beneficial for air traffic planning and management. The empirical analysis also reflects that the evaluation model based on the uncertainty transformation model can transform the quantitative data of network structure and traffic function into the qualitative language of reliability.

Comparing the modeling of delay propagation in the US and European air traffic networks

2016 ◽  
Vol 56 ◽  
pp. 12-18 ◽  
Author(s):  
Bruno Campanelli ◽  
Pablo Fleurquin ◽  
Andrés Arranz ◽  
Izaro Etxebarria ◽  
Carla Ciruelos ◽  
...  
Keyword(s):  
Air Traffic ◽  
Traffic Networks ◽  
Delay Propagation ◽  
The Us

Chemistry instructors’ intentions toward developing, teaching, and assessing student representational competence skills

2021 ◽  
Author(s):  
Maia Popova ◽  
Tamera Jones
Keyword(s):  
Professional Development ◽  
Coding Theory ◽  
Assessment Practices ◽  
Self Awareness ◽  
Scientific Practices ◽  
Information Processing Model ◽  
Representational Competence ◽  
Evidence Based Practices ◽  
Factors Affecting ◽  
The Us

Representational competence is one's ability to use disciplinary representations for learning, communicating, and problem-solving. These skills are at the heart of engagement in scientific practices and were recognized by the ACS Examinations Institute as one of ten anchoring concepts. Despite the important role that representational competence plays in student success in chemistry and the considerable number of investigations into students’ ability to reason with representations, very few studies have examined chemistry instructors’ approaches toward developing student representational competence. This study interviewed thirteen chemistry instructors from eleven different universities across the US about their intentions to develop, teach, and assess student representational competence skills. We found that most instructors do not aim to help students develop any representational competence skills. At the same time, participants’ descriptions of their instructional and assessment practices revealed that, without realizing it, most are likely to teach and assess several representational competence skills in their courses. A closer examination of these skills revealed a focus on lower-level representational competence skills (e.g., the ability to interpret and generate representations) and a lack of a focus on higher-level meta-representational competence skills (e.g., the ability to describe affordances and limitations of representations). Finally, some instructors reported self-awareness about their lack of knowledge about effective teaching about representations and the majority expressed a desire for professional development opportunities to learn about differences in how experts and novices conceptualize representations, about evidence-based practices for teaching about representations, and about how to assess student mastery of representational competence skills. This study holds clear implications for informing chemistry instructors’ professional development initiatives. Such training needs to help instructors take cognizance of relevant theories of learning (e.g., constructivism, dual-coding theory, information processing model, Johnstone's triangle), and the key factors affecting students’ ability to reason with representations, as well as foster awareness of representational competence skills and how to support students in learning with representations.

The Economics of Air Traffic Control

1980 ◽  
Vol 33 (1) ◽  
pp. 23-29
Author(s):  
Angus Hislop
Keyword(s):  
Traffic Control ◽  
Air Traffic Control ◽  
Air Traffic ◽  
Air Transport ◽  
Civil Aviation ◽  
Department Of Transportation ◽  
Private Industry ◽  
The Us ◽  
The Uk

This paper is based mainly on a study carried out in 1976/7 for the UK Department of Industry into the long-term development of air traffic control systems in Europe by a team drawn from the Civil Aviation Authority, the Royal Signals and Radar Establishment and private industry, in which Coopers and Lybrand provided the economic expertise.Until the early 1970s, air traffic control was almost completely neglected by air transport economists. Economists contributed to the planning of airports and airline operations but not to the third facet of the air transport system. However, in 1970–1, in conjunction with a programme of expansion and improvement of the country's airports and airways, the US Department of Transportation launched a major study of the airport and airways system. This was designed to establish an equitable charging policy between the different categories of user but in the event its recommendations in this area have only recently begun to be followed.

scholarly journals Methods for division of road traffic network for distributed simulation performed on heterogeneous clusters

2013 ◽  
Vol 10 (1) ◽  
pp. 321-348 ◽  
Author(s):  
Tomas Potuzak
Keyword(s):  
Road Traffic ◽  
Distributed Simulation ◽  
Computation Time ◽  
Traffic Network ◽  
Traffic Networks ◽  
Computing Environment ◽  
Heterogeneous Cluster ◽  
Heterogeneous Clusters ◽  
The Road ◽  
Road Traffic Networks

The computer simulation of road traffic is an important tool for control and analysis of road traffic networks. Due to their requirements for computation time (especially for large road traffic networks), many simulators of the road traffic has been adapted for distributed computing environment where combined power of multiple interconnected computers (nodes) is utilized. In this case, the road traffic network is divided into required number of sub-networks, whose simulation is then performed on particular nodes of the distributed computer. The distributed computer can be a homogenous (with nodes of the same computational power) or a heterogeneous cluster (with nodes of various powers). In this paper, we present two methods for road traffic network division for heterogeneous clusters. These methods consider the different computational powers of the particular nodes determined using a benchmark during the road traffic network division.

scholarly journals Factors Affecting the Design and Economic Operation of Distribution Networks and Its Investigation in the 0.4 KV Distribution Network of Ghazni City

2021 ◽  
Vol 3 (27) ◽  
pp. 101-115
Author(s):  
Massoud Danishmal ◽  
Keyword(s):  
Power Distribution ◽  
Distribution Systems ◽  
Network Reliability ◽  
Distribution Network ◽  
Distribution Networks ◽  
Electricity Demand ◽  
Power Distribution Systems ◽  
Factors Affecting ◽  
Economic Operation ◽  
Selection Of

The design of power distribution systems should be such that it can technically respond to the increase in electricity demand properly and economically, optimally designed and high network reliability. In order to respond to the increase in electricity demand, load forecasting must be done so that in addition to providing the electricity needed by customers, expansion of power generation centers, expansion of substations, expansion of transformer stations and selection of their appropriate location can be done optimally. In this article, we first examine the definitions and factors that are technically and economically effective in the economic design of energy distribution systems. And in the next stage, we will see whether these above-mentioned effective factors are considered in the 0.4 kV distribution network of Ghazni city or not.

scholarly journals FAKTOR-FAKTOR YANG MEMPENGARUHI JUMLAH KUNJUNGAN WISATAWAN DI PROPINSI SUMATERA UTARA

2021 ◽  
Vol 4 (1) ◽  
pp. 1-10
Author(s):  
Enita Rosmika
Keyword(s):  
Exchange Rate ◽  
General Knowledge ◽  
Product Knowledge ◽  
Climate History ◽  
Dollar Exchange Rate ◽  
Factors Affecting ◽  
Independent Variables ◽  
Tourism Product ◽  
The Us ◽  
Us Dollar

Tourism Product Knowledge is regarding the general knowledge of all regions in Indonesia which includes the location of the region / geography, climate, history, politics, culture, and particularly object - attractions and facilities and attractions which support it. In this study, entitled Factors Affecting Total tourist arrivals in Sumut Province Year Period 2014 -2019. The purpose of this study was to determine the number of rooms and the dollar exchange rate partially and simultaneously inuence the number of tourist arrivals in Sumut, in order to obtain a result the number of hotel rooms inuential not evident partially on the number of tourists visiting the province of Sumut, because t smaller than t table or -1.651 <1.761 while the dollar exchange rate has a signicant effect on the number of tourists visiting the province of Sumut, because t is greater than t table or 2.236> 1.740 and Total Room and the US dollar exchange rate simultaneously or together of the number of tourists visiting Sumut Province since F count> F table or 13.288> 3.59. The magnitude of the effect of independent variables on the dependent variable simultaneously can be known from the value of the coefcient of determination (R2) is equal to 0.639. This means that both variables jointly contribute to or inuence amounted to 63.9 percent of the number of tourists visiting the province of Sumut, while the remaining 36.1 percent is inuenced by other variables that are not described in the model, such as safety, service, facilities.

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