IP Mobility Issues for a Mobile Tele-Robotic System-NEPWAK

The network-centric applied research team (N-CART) is continuing its work on an ambitious project known as the network-enabled powered wheelchair adaptor kit (NEPWAK). It introduces techniques for modifying and using powered wheelchairs as mobile platforms enabling communication and remote control. The wheelchair is equipped with a laptop computer, a CCD camera and a wireless network interface card (NIC) for 802.11b Internet access. The laptop acts as a server allowing network clients to gain access through a custom control interface on the chair. The remote controlling client receives a video and audio feed from the chair and sends control signals for maneuvering. While traveling, the chair is able to change its network association from one access point (AP) to another within the same subnet-the process is known as handoff. However, there is no inter-network handoff mechanism presently available in IP networks. This restricts the mobility of the wheelchair to within the coverage area of the subnet APs. This paper shows that the Internet engineering task force's (IETF) network layer mobility protocol-Mobile IP suffers from large handoff latencies that can hinder communication between the client and the wheelchair during handoff. Mobile IP alone is not a sufficient solution for a mobile telebotic system such as NEPWAK. An interesting solution to the handoff latency problem comes from the Fast-handover protocol described in Section 4.4 with simulation results in Section 6.2.     

Architectural Concepts of a Semi-autonomous Wheelchair

A new smart, sensor-assisted wheelchair system for the vocational rehabilitation of people with severe and multiple handicap has been developed in the research project OMNI within the CEC TIDE programme. The project finished in December 1996. The objective of the project was the development of an advanced wheelchair with omnidirectional manoeuvrability and navigational intelligence that is well suited for vocational rehabilitation. It provides an opportunity of intuitive wheelchair control to people with severe physical or multiple (incl. mental) handicap. Cramped offices are made accessible by the small outline, high mobility and navigational support of the chair. The user's safety and driving accuracy are guaranteed by a novel sensor system and navigation modules. A wide range of control devices can be used with the adaptable human-machine interface which also controls environmental devices. Within this project, the user focused principle has strongly been followed (this includes the involvement of users from the preparatory work to the evaluation of the results).     

Cooperative Strategy for a Wheelchair and a Robot to Climb and Descend a Step

This paper discusses a cooperative strategy that enables a wheelchair and a wheeled robot to climb and descend a step. In this method, not only does the robot assist the wheelchair user, but also the user assists the robot to overcome the step. The research indicates the feasibility of this new cooperative strategy between a physically disabled person and a personal robot that is not designed for high-level performance. The two vehicles (the wheelchair and the wheeled robot) are connected by a simple link mechanism, the two connecting positions of which are free joints. This method is especially affected by the link positions. A numerical calculation clarifies the combinations of the two link positions to avoid a collision between each vehicle and to overcome a step at the same time. The result of the simulations indicate that it is necessary to change the link positions to climb and descend a step safely. The experimental results show that this method is effective.     

Smart mobile computation offloading: Centralized selective and multi-objective approach

Although mobile devices have been considerably upgraded to more powerful terminals, yet their lightness feature still impose intrinsic limitations in their computation capability, storage capacity and battery lifetime. With the ability to release and augment the limited resources of mobile devices, mobile cloud computing has drawn significant research attention allowing computations to be offloaded and executed on remote resourceful infrastructure. Nevertheless, circumstances like mobility, latency, applications execution overload and mobile device state; any can affect the offloading decision, which might dictate local execution for some tasks and remote execution for others. We present in this article a novel system model for computations offloading which goes beyond existing works with smart centralized, selective, and optimized approach. The proposition consists of (1)hotspots selection mechanism to minimize the overhead of the offloading evaluation process yet without jeopardizing the discovery of the optimal processing environment of tasks, (2)a multi-objective optimization model that considers adaptable metrics crucial for minimizing device resource usage and augmenting its performance, and (3)a tailored centralized decision maker that uses genetics to intelligently find the optimal distribution of tasks. The scalability, overhead and performance of the proposed hotspots selection mechanism and hence its effect on the decision maker and tasks dissemination are evaluated. The results show its ability to notably reduce the evaluation cost while the decision maker was able in turn to maintain optimal dissemination of tasks. The model is also evaluated and the experiments prove its competency over existing models with execution speedup and significant reduction in the CPU usage, memory consumption and energy loss.     

Modelling and design of an augmented reality differential drive mobility aid in an enabled environment

In this paper the authors discuss the modelling and design of an augmented reality platform for disabled wheeled mobility studies. This design consists of a virtual environment with two degrees of freedom motion platform and integrated ground contact force feedback. Differential drive mobility users continue to be in touch with reality on their own mobility aid while interacting with virtual objects. The major domain related to the differential drive mobility of the disabled members of society which coincides with the use of manual wheelchairs, electric wheelchairs and mobility scooters. In order to account for environmental and dynamic effects, the wheeled mobility user needs to map the intended trajectory into the virtual world. Motion and inertia force feedback produced on the augmented simulator give the users a haptic sensory stimulus input regarding spatial movement and ground contact forces. The main objective is to model and design an augmented reality platform with real world kinematic and dynamic properties to place a wheeled mobility user closer to real world encounters. The use of the designed augmented reality platform will be beneficial to disabled wheeled mobility users in need of occupational therapist training and evaluation.     

基于互联网技术的远程机器人控制器设计

采取利用互联网、IEEE802．11x无线局域网及移动电话网的方法,为轮式移动机器人设计具有视觉功能的远程无线控制器,实现远程无线控制轮式移动机器人的控制器软件、硬件的基本结构和设计方法。设计的两种嵌入式控制器分别在局域网和日本的3G无线移动电话网上进行了实验,在具有视觉功能的轮式移动机器人上实现了利用浏览器通过网络对轮式移动机器人进行远程无线操作控制,并在远程操作计算机上通过网络利用浏览器获取机器人实时视觉图像。     

保留细节特征的轮廓线远程绘制算法

目前,智能掌上电脑、个人数字助理和智能手机等移动终端因为其便携性和可移动性,越来越多地被应用于分布式虚拟环境中,但是因为移动终端自身的局限性,在移动终端上的3维模型实时绘制问题仍未得到很好的解决。结合多分辨率网格模型和基于轮廓线的远程绘制的优点,提出了一种保留细节特征的轮廓线远程绘制算法。该算法预处理阶段,在原始精细网格模型上提取细节特征线,并进行多分辨率网格模型的预处理;运行时阶段,根据视点、帧率等交互信息使用选取策略对细节特征线进行选取,然后构建合适的多分辨率网格模型,并在该模型上提取出外围轮廓线,最后发送这两种轮廓线到移动终端进行绘制。实验结果表明,该算法在基于轮廓线的远程绘制中较好地保留了模型的细节特征,并保证了在移动终端的实时绘制。     

Seating discomfort for tractor operators – a critical review

A large number of studies have been conducted and researchers have suggested several criteria for evaluating discomfort and the suitability of a tractor seat in a given working condition. The studies have led to various parameters, viz. the body pressure distributed under and supporting both the buttocks, thighs and the back of an operator, control of posture in static or dynamic condition, ride vibration, exposure time on task and other factors. But in the absence of a more definitive and the most logical criteria particularly from biomechanical viewpoint, the researchers will continue to design conditions and procedures to understand the seat dynamics and evaluate the seating discomfort. Therefore, this paper reviews the research information available in this regard and attempts to set the most appropriate procedure for assessment of seating discomfort during tractor driving.

Relevance to industry

This paper attempts to project the most appropriate method of assessment and selection of tractor seats from engineering and biomechanical view point which could be adopted by the tractor seat manufacturers. It is designed to enhance the feeling of comfort, safety, convenience, and results in higher work output from the operator.     

Design and testing of a low-cost robotic wheelchair prototype

Many people who are mobility impaired are, for a variety of reasons, incapable of using an ordinary wheelchair. In some instances, a power wheelchair also cannot be used, usually because of the difficulty the person has in controlling it (often due to additional disabilities). This paper describes two low-cost robotic wheelchair prototypes that assist the operator of the chair in avoiding obstacles, going to pre-designated places, and maneuvering through doorways and other narrow or crowded areas. These systems can be interfaced to a variety of input devices, and can give the operator as much or as little moment by moment control of the chair as they wish. This paper describes both systems, the evolution from one system to another, and the lessons learned.     

Landscape research,landscape policy and Earth observation

'Landscape' refers explicitly to spatial structures of outdoor environments and the role of these structures in nature and society. Since repetitive land coverages of Earth observation systems such as SPOT (Systéme Probatoire pour l'Observation de la Terre) and Landsat provide a wealth of landscape images from local to continental scale, one would expect a more systematic use of these data by landscape researchers and planners than is currently the case. This paper states that the divergence between the central goals, vocabularies and methods in the distinct fields of landscape research, landscape policy and remote sensing may be prohibiting a systematic implementation. Examples are given in which the methodological steps necessary to bridge the gaps between these fields are explained. These are based on experiences in remote sensing data analysis for landscape ecological and landscape planning projects. The coverage over extensive areas, the grid format and the multi-temporal facility remain major assets of remote sensing. At continental scales, the coverage of remote sensing images in Europe is less complete than expected given the length of operation of both SPOT and Landsat Thematic Mapper (TM). Integration with spatial datasets of different origin (soil maps, road maps, etc.) is necessary to cover basic information needs. For landscape planners and researchers in general, specific qualities of spatial data are more relevant than their remote sensing origin. This is an important fact in stimulating the use of Earth observation data in landscape research. The mere presence of satellite images and their derived products (such as land cover datasets) is a 'push' factor both for landscape research and policy and the implementation of scientific knowledge and models into planning and policy. The task of 'intermediators' should be recognized against classical, if not mythical, 'data providers' and 'end users' commonly identified in Earth observation.     

IP mobility issues for a mobile tele-robotic system—NEPWAK

The network-centric applied research team (N-CART) is continuing its work on an ambitious project known as the network-enabled powered wheelchair adaptor kit (NEPWAK). It introduces techniques for modifying and using powered wheelchairs as mobile platforms enabling communication and remote control. The wheelchair is equipped with a laptop computer, a CCD camera and a wireless network interface card (NIC) for 802.11b Internet access. The laptop acts as a server allowing network clients to gain access through a custom control interface on the chair. The remote controlling client receives a video and audio feed from the chair and sends control signals for maneuvering. While traveling, the chair is able to change its network association from one access point (AP) to another within the same subnet–the process is known as handoff. However, there is no inter-network handoff mechanism presently available in IP networks. This restricts the mobility of the wheelchair to within the coverage area of the subnet APs. This paper shows that the Internet engineering task force’s(IETF) network layer mobility protocol—Mobile IP[1] suffers from large handoff latencies that can hinder communication between the client and the wheelchair during handoff. Mobile IP alone is not a suffcient solution for a mobile telebotic system such as NEPWAK. An interesting solution to the handoff latency problem comes from the Fast-handover protocol[2] described in Section 4.4 with simulation results in Section 6.2.     

Effects of COVID-19 on a CMOS fabrication course: An integrated design experience

In the CMOS fabrication course described herein, the lecture component provides the theoretical background for semiconductor materials and integrated circuit fabrication processes. The laboratory component provides the hands-on experience required to fabricate and electrically characterize CMOS circuits in a one-semester format. A strong semiconductor device process design thread is achieved in the course by integrating the laboratory experience and process simulation/modeling and theoretical calculations. The risks associated with the COVID-19 pandemic have forced significant course modifications. The lecture is switched to a remote learning format, including pre-recorded content and weekly advanced Q&A sessions. The laboratory provides both in-person and remote sessions. Approved social distancing and cleaning protocols are practiced in the facility for in-person learning. Complementary remote learning resources are made available to all the students such as pre-recorded laboratory instructions, live video-based laboratory sessions, and web-based supplementary information. Compared to pre-pandemic semesters, the average students' GPA of the pandemic period has increased, attributed to larger and archived volumes of instructional material. Overall student comments related to course changes necessitated by the pandemic are mixed with both positive and negative feedback.     

高光谱遥感图像波段选择研究进展综述

高光谱成像遥感技术可获取地物的光谱、辐射和空间信息,在国民经济的各个领域得到广泛的应用.但其狭窄的波段间距带来丰富光谱信息的同时,也带来了信息冗余,增加了数据处理的难度.因此,高光谱遥感数据在进行实际应用前,需要进行波段选择并提取光谱特征,降低数据维数.对高光谱遥感图像的波段选择研究进展进行了综述,在分析、归纳波段选择...     

基于激光和单目相机信息融合的智能轮椅避障策略研究

针对智能轮椅使用环境复杂多变,障碍物形状各异,单一传感器无法获得完整的环境信息的问题,提出一种基于激光传感器和单目视觉传感器信息融合的障碍物检测方法。通过单目相机和激光雷达传感器感知智能轮椅周围环境,得到障碍物的形状、距离分布状况等信息;在此基础上提出两种传感器信息的融合策略,建立局部障碍物地图,进一步采用模糊神经网络完成整体避障算法,实现智能轮椅安全、快速避障等功能。实验结果验证了文中所提避障算法的可行性及有效性。     

Mobility evaluation of wheeled all-terrain robots

Standardized performance evaluation is uncommon in mobile robotics. Therefore, it is difficult to compare published results and estimate their value. This work aims at providing a basis for the evaluation and comparison of the mobility performance of wheeled, all-terrain robots with respect to terrainability. Precisely defined existing and novel metrics are proposed for this purpose. The utility of these metrics is shown by applying them in a comparison to a selection of rover suspension systems known from the literature. Appropriate models for evaluation of the performance are described as well as the validation of the metrics by means of experimental testing. The simulations reveal significant differences in performance between the rovers which is confirmed by the test results. The correlation of the performance in simulation and reality is highly satisfying and supports the applicability of the proposed metrics.     

The Vahm Robotized Wheelchair: System Architecture and Human-Machine Interaction

In the smart wheelchair field the research problematics consists in applying methods coming from mobile robotics to navigation assistance for people with motor disabilities. In this paper we detail the constraints and the specificities of this application. From this study we deduce the need to obtain a cooperation between the human operator and the machine in order to achieve a mobility task. To illustrate this purpose, we describe a mobile robot architecture which facilitates task and information sharing and trading between man and machine.     

Man-machine Cooperation for the Control of an Intelligent Powered Wheelchair

In the smart wheelchair field the research problematics consists in applying methods coming from mobile robotics to navigation assistance for people with motor disabilities. In this chapter we detail the constraints and the specificities of this application. From this study we deduce the need to obtain a cooperation between the human operator and the machine in order to achieve a mobility task. To illustrate this purpose, we describe a mobile robot architecture which facilitates task and information sharing and trading between man and machine.     

Land Cover Extraction in the Ejina Oasis by Hyperspectral Remote Sensing

The extraction of land surface coverage is the basis of ecological environment evaluation,vegetation change analysis and regional ecological and hydrological processes.Aerial hyperspectral remote sensing has great advantage in land surface coverage extraction,such as flexible,wide coverage,high spatial resolution and high spectral resolution.Research area has landscape characteristics of vegetation,landscape fragmentation and heterogeneity in Ejina Poplar Forest National Nature Reserve.Comparison and analysis of two methods of dimension reduction based on minimum noise transform and principal component analysis,three supervised classification methods based on maximum likelihood method,support vector machine and object\|oriented classification.Land surface coverage is extracted by NDVI threshold segmentation,minimum noise transform dimensionality reduction method and maximum likelihood classification method according to the characteristics of landscape fragmentation,heterogeneity and high redundancy of hyperspectral data based on the Airborne Hyperspectral Data of Ejina oasis in the lower reaches of Heihe.The land surface coverage results overall accuracy and Kappa coefficient are 87.95% and 0.885 by random sampling based on airborne remote sensing data.The results show that the classification results of high accuracy can provide effective parameters for ecological research.     

Implementing an emerging mobility model for a fleet of UAVs based on a fuzzy logic inference system

In this paper, we design and implement a novel generic mobility model, named Alpha-based, for a fleet of small interconnected UAVs (Unmanned Aerial Vehicles) that collaborate to explore a geographic area (battle field, research and rescue missions, surveillance applications, etc.). In fact, due to the significant impact of mobility models on the networking performance, the mobility models must realistically capture the UAV’s attributes. Hence, we propose to use a combination of energy level, coverage-area and network connectivity for mobility decision-making, in contrast to the literature where only network connectivity and area coverage are investigated. On the one hand, these two metrics are very important, especially for applications where achieving the best area-coverage and maintaining network connectivity represent an essential requirement. On the other hand, energy is another equally noteworthy constraint that should be taken into account. In fact, being a crucial resource for all mobile devices and especially for UAVs, the energy becomes vital to ensure the network lifetime and mission success. As far as we know, Alpha-based mobility model is the first to ever consider a combination of these three metrics within the same decision-making criterion. A distributed scheme is adopted, where each UAV determines locally its future movement based on the information it receives from its neighbors. Moreover, a novel fuzzy inference system is implemented in order to compute the values of a followship weighting parameter, named Alpha. This latter is used to choose the most suitable neighboring UAV to follow. To validate the proposed mobility model, rigorous testing has been accomplished, through simulation work. Compared to Random-based and Forces-based mobility models, the Alpha-based mobility model achieves good coverage rate while maintaining connectivity.     

基于MEMS激光雷达的智能轮椅SLAM研究

轮椅是残障人士和老年人的重要代步工具,传统的电动、手动轮椅移动方式单一,需要他人辅助完成,且无法主动保证使用者的安全。研究了基于机器人操作系统(ROS)的轮椅室外场景建模、路径规划与导航算法。在轮椅上安装MEMS激光雷达,融合体素网格滤波器和LeGO-LOAM算法完成点云处理和室外场景建模;设计了融合百度地图和激光雷达的轮椅导航方式,使用者可根据百度地图提供的路径规划信息遥控轮椅,在建图完毕后,可仅依靠激光雷达完成路径导航和自主移动;结合激光雷达智能感知算法,实现了道路信息的实时感知,使轮椅具备主动安全功能。通过实验验证了建模、感知算法的功能,并完成了融合导航仿真实验,研究内容能够大幅提升智能轮椅使用过程中的安全性能。