Traffic Simulation in SAGIN Air Segment Containing Ad Hoc Network of Flying Drones

The purpose of this article is to simulate data transmission and calculate traffic parameters in SAGIN air segment for which Ad Hoc network of flying drones is considered as a model. Traffic modeling is based on the manet-routing-compare example from the ns3 simulator library, which has been supplemented with the code for calculation packet losses, throughput/goodput, and message transmission delays. The program allowed considering drones movement at both low and high speeds from 3.6 km/h to 72 km/h. The dependences of traffic losses on data transmission power, transaction sizes and data transmission rate are obtained and analyzed. The distribution of the average effective arrival rate λ and the throughput/goodput for drones has been studied. Comparing traffic characteristics in models with different numbers of drones allows judging how the required quality of service can be achieved by choosing the right transmission parameters.

A Review of Studying the Relationship of Traffic Stream Characteristics and Noise Intensity with Flexible Pavement Surface Condition

In general, roads are a very important infrastructure to facilitate people’s access to their social and economic activities, so knowing the things that affect the efficiency of these roads is very important and how to maintain them. One of the aims of this research is to shed light on previous studies that showed the relationship between traffic characteristics and noise intensity on the condition of the breakable Pavement. The results of previous studies show that flexible Pavement has 19 potential failures and how to address them. There is a relationship between the characteristics of traffic flow and failures that occur in flexible paving. It is also possible to calculate the road condition by knowing the types of faults on the road using several roads or by using specific formulas to calculate the road condition index. There are relationships between the road condition index, the vehicles’ speed, and the models that link Noise to speed. And that most of the relationships that were used to calculate the elastic pavement condition index and its relationship to the movement characteristics are statistical relationships using ANOVA, recreation, and R2

An efficient routing strategy for coupled spatial networks

The study of traffic dynamics on couple networks is important for the design and management of many real systems. In this paper, an efficient routing strategy on coupled spatial networks is proposed, considering both traffic characteristics and network topology information. With the routing strategy, the traffic capacity can be greatly improved in both scenarios of identical and heterogeneous node capacity allocation. Heterogeneous allocation strategy of node delivery capacity performs better than identical capacity allocation strategy. The study can help to improve the performance of real-world multi-modal traffic systems.

On stability of distributions of WhatsApp traffic characteristics

This paper deals with the main methods of traffic classification and describes the functional scheme of a test bench and the test procedure. It provides the results of verifying the hypothesis about the stability of distributions of WhatsApp traffic characteristics. The delivered test results in this paper emphasize the influence of certain traffic characteristics on the final traffic distribution form. In addition, the comparison of the results obtained for the entire set of tests and the results received for individual test sets reveals the absence of other critical traffic characteristics significantly influencing the distribution form concluding in the need for further research. The paper concludes that the stability pattern of distributions of WhatsApp traffic characteristics can be obtained and visualized after more critical traffic characteristics are revealed and processed in similar tests. This paper stands as a pioneer research in assessing the traffic analysis and implementing the results in applied science.

Packet Flow Capacity Autonomous Operation Based on Reinforcement Learning

As the dynamicity of the traffic increases, the need for self-network operation becomes more evident. One of the solutions that might bring cost savings to network operators is the dynamic capacity management of large packet flows, especially in the context of packet over optical networks. Machine Learning, particularly Reinforcement Learning, seems to be an enabler for autonomicity as a result of its inherent capacity to learn from experience. However, precisely because of that, RL methods might not be able to provide the required performance (e.g., delay, packet loss, and capacity overprovisioning) when managing the capacity of packet flows, until they learn the optimal policy. In view of that, we propose a management lifecycle with three phases: (i) a self-tuned threshold-based approach operating just after the packet flow is set up and until enough data on the traffic characteristics are available; (ii) an RL operation based on models pre-trained with a generic traffic profile; and (iii) an RL operation with models trained for real traffic. Exhaustive simulation results confirm the poor performance of RL algorithms until the optimal policy is learnt and when traffic characteristics change over time, which prevents deploying such methods in operators’ networks. In contrast, the proposed lifecycle outperforms benchmarking approaches, achieving noticeable performance from the beginning of operation while showing robustness against traffic changes.

Driver Behavior When Overtaking Cyclists Riding in Different Group Configurations on Two-Lane Rural Roads

The presence of cyclists on Spanish rural roads is ever increasing and currently frequent, and thus becoming a serious safety concern. In rural environments, the risk of a crash is higher than in rural areas. The main cause is the higher speed of motor vehicles during overtaking manoeuvres. This manoeuvre is especially challenging when cyclists ride in groups as they may change size, length, shape, and speed along their route. These variables and those related to road cross-section can influence driver behaviour when overtaking a group of cyclists. To study this, instrumented bicycles were used to ride along five road segments with different geometric and traffic characteristics. Cyclists rode individually and in groups. Overtaking was evaluated by analysing the lateral distance, the speed, and other characteristics of the manoeuvre. Wider roads presented higher lateral clearances and overtaking speeds. Narrower roads had a high opposing lane invasion but a high level of compliance with the minimum lateral clearance. A higher clearance and lower speed of overtaking vehicles was registered when cyclists rode in line. Compliance with the 1.5 m clearance depended on the group configuration, being higher when cyclists rode in line. However, overtaking cyclists riding two abreast presented more accelerative manoeuvres, especially on narrow roads.

Operating Speed Prediction Models for Tangent Segments: A Brief Review

This paper provides a review of studies aimed at developing operating speed prediction models for road tangent sections. The review included many studies, conducted in different geographical areas of the world, in terms of road classification, types of vehicles, techniques and devices used in data collection, number of study sites, the principle adopted in extracting the free-flow speed, as well as the topography that the road path passes through and grads of the studied sections. Moreover, this review mentioned the analysis methods adopted in the modeling, and included the model formulas that the researchers have reached in their studies, as it showed all the geometric elements and traffic characteristics that appeared in the models as independent variables. The author has avoided critiquing or evaluating the methodologies of the reviewed research and accordingly this paper has been prepared for documentation only. The author aims primarily to save the effort and time of graduate students and researchers interested in modeling the operating speed on straight segments, as all data and information are arranged in tables and coordinated for this purpose. Doi: 10.28991/cej-2021-03091784 Full Text: PDF

Networked Compact City Policy Status and Issues—Hierarchy and Human Mobility in Tokyo, Japan

As a policy to promote compact cities, Japan formulated the Location Normalization Plan (LNP) in 2014. By this plan, each municipality is promoting the establishment of Urban Function Induction-encouraged Areas (UFIA) in which life service facilities are to be provided. The role of the UFIA in the region might differ depending on the city scale and the UFIA hierarchy. For this study, using the Tokyo Person Trip survey, we specifically examined the mobility of people and clarified differences in the hierarchical nature of UFIA to ascertain the current status and issues of UFIA. Consequently, we obtained the following information for the realization of compactness. (1) The actual conditions of traffic characteristics and facilities differ depending on the UFIA hierarchy. Moreover, considering these hierarchies during the study of UFIA is important. (2) Sub-core UFIA in cities with a large population have a narrow usage area and a high ratio of traffic-sharing between walking and bicycling, which might engender the construction of compact living areas. (3) However, sub-core UFIA in cities with a small population have a high ratio of traffic-sharing of automobiles and a wide usage area, which presents challenges for compact city realization.