A Comparison of Performance between Macro-mobility Protocol and Micro-mobility Protocol

Mobile IP is the proposed standard for IP mobility support. When a MobileNode (MN) is far away from home, registration at its home agent can cause a long handoff delay thatleads to significant packet drop and throughput reduction. In order to improve standard mobile IP,the mobility of MN has been divided into micro-mobility and macro-mobility. Some micro-mobilitymanagement protocols have been developed. We compare the performance between standard mobile IP(RFC2002, RFC3220, RFC3344) and micro-mobility management protocols and give some equations alongwith the analysis of calculating results.

Hierarchical micro-mobility management in high-speed multihop access networks

This article integrates the hierarchical micro-mobility management and the high-speed multihop access networks （HMAN）, to accomplish the smooth handover between different access reuters. The proposed soft handover scheme in the high-speed HMAN can solve the micro-mobility management problem in the access network. This article also proposes the hybrid access muter （AR） advertisement scheme and AR selection algorithm, which uses the time delay and stable route to the AR as the gateway selection parameters. By simulation, the proposed micro-mobility,management scheme can achieve high packet delivery fraction and improve the lifetime of network.

On the simulation of shared autonomous micro-mobility

Fast urbanization and climate change require innovative systems for an efficient movement of people and goods in cities.As trends towards vehicle-sharing,autonomous vehicles,and the use of micro-mobility systems gain strength,the intersection of these fields appears as an area of great opportunity.Autonomy could potentially bring the convenience of on-demand mobility into already prevalent shared micro-mobility systems(SMMS),increasing their efficiency and incentivizing more people to use active mobility modes.The novelty of introducing autonomous driving technology into SMMS and their inherent complexity requires tools to assess and quantify the potential impact of autonomy on fleet performance and user experience.This paper presents an ad-hoc agentbased simulator for the assessment of the fleet behavior of autonomous SMMS in realistic scenarios,including a rebalancing system based on demand prediction.It also allows comparing its performance to station-based and dockless schemes.The proposed simulation framework is highly configurable and flexible and works with high resolution and precision geospatial data.The results of studies carried out with this simulation tool could provide valuable insights for many stakeholders,including vehicle design engineers,fleet operators,city planners,and governments.

Autonomous vehicles for micro-mobility

Autonomous vehicles have been envisioned for more than 100 years.One of the first suggestions was a front cover of Scientific America back in 1916.Today,it is possible to get cars that drive autonomously for extended distances.We are also starting to see micro-mobility solutions,such as the Nuro vehicles for pizza delivery.Building autonomous cars that can operate in urban environments with a diverse set of road-users is far from trivial.Early 2018 the Contextual Robotics Institute at UC San Diego launched an effort to build a full stack autonomous vehicle for micro-mobility.The motivations were diverse:i)development of a system for operation in an environment with many pedestrians,ii)design of a system that does not rely on dense maps(or HD-maps as they are sometimes named),iii)design strategies to build truly robust systems,and iv)a framework to educate next-generation engineers.In this paper,we present the research effort of design,prototyping,and evaluation of such a vehicle.From the evaluation,several research directions are explored to account for shortcomings.Lessons and issues for future work are additionally drawn from this work.

移动IP技术分析

移动IPv4是基于网络层的移动管理协议,无论从位置管理还是移动切换管理都采用基于网络层IP来实现。作为支持宏观移动的技术,移动IP可以与微观移动的技术,如蜂窝IP等相结合应用。本文着重介绍移动IPv4技术的基本原理,同时从安全、路由和网络层的移动切换的角度,引入相关的补充技术,如安全认证机制、路由优化技术和平滑切换技术,提供完善的移动IP实现。

A spatiotemporal analysis of the impact of lockdown and coronavirus on London’s bicycle hire scheme:from response to recovery to a new normal

The coronavirus pandemic that started in 2019 has had wide-ranging impacts on many aspects of people’s daily lives.At the peak of the outbreak,lockdown measures and social distancing changed the ways in which cities function.In particular,they had profound impacts on urban transportation systems,with public transport being shut down in many cities.Bike share systems(BSS)were widely reported as having experienced an increase in demand during the early stages of the pandemic before returning to pre-pandemic levels.However,the studies published to date focus mainly on the first year of the pandemic,when various waves saw continual relaxing and reintroductions of restrictions.Therefore,they fall short of exploring the role of BSS as we move to the post-pandemic period.To address this gap,this study uses origin-destination(O-D)flow data from London’s Santander Cycle Hire Scheme from 2019-2021 to analyze the changing use of BSS throughout the first two years of the pandemic,from lockdown to recovery.A Gaussian mixture model(GMM)is used to cluster 2019 BSS trips into three distinct clusters based on their duration and distance.The clusters are used as a reference from which to measure spatial and temporal change in 2020 and 2021.In agreement with previous research,BSS usage was found to have declined by nearly 30%during the first lockdown.Usage then saw a sharp increase as restrictions were lifted,characterized by longer,less direct trips throughout the afternoon rather than typical peak commuting trips.Although the aggregate number of BSS trips appeared to return to normal by October 2020,this was against the backdrop of continuing restrictions on international travel and work from home orders.The period between July and December 2021 was the first period that all government restrictions were lifted.During this time,BSS trips reached higher levels than in 2019.Spatio-temporal analysis indicates a shift away from the traditional morning and evening peak to a more diffuse pattern of working hours.The results indicate that the pandemic may have had sustained impacts on travel behavior,leading to a“new normal”that reflects different ways of working.

On the performance of shared autonomous bicycles:A simulation study

As society faces global challenges such as population growth and climate change,rethinking cities is now more imperative than ever.The design of cities can not be abstracted from the design of their mobility systems.Therefore,efficient solutions must be found to transport people and goods throughout the city efficiently and ecologically.An autonomous bicycle-sharing system would combine the most relevant benefits of vehicle-sharing,autonomy,and micro-mobility,increasing the efficiency and convenience of bicycle-sharing systems and incentivizing more people to bike and enjoy their cities in an environmentally friendly way.Due to the novelty of introducing autonomous driving technology into bicycle-sharing systems and their inherent complexity,there is a need to quantify the potential impact of autonomy on fleet performance and user experience.This paper presents the results of an agent-based simulation that provides an in-depth understanding of the fleet behavior of autonomous bicycle-sharing systems in realistic scenarios,including a rebalancing system based on demand prediction.In addition,this work describes the impact of different parameters on system efficiency and service quality.Finally,it quantifies the extent to which an autonomous system would outperform current station-based and dockless bicycle-sharing schemes.The obtained results show that with a fleet size three and a half times smaller than a station-based system and eight times smaller than a dockless system,an autonomous system can improve overall performance and user experience even with no rebalancing.