A model for predicting pathologist's velocity profiles when navigating virtual slides

Navigation through large microscopic images is a potential benefit for histology or pathology teaching, for improving the quality of diagnosis in pathology, or for communicating pathologists in some telemedicine applications. However, the size of this kind of images is prohibitive for navigation with conventional techniques. This article presents a soft computing model, which permits to anticipate the pathologist trajectories in diagnosis tasks when exploring virtual slides. The Bayesian strategy combines an offline model of a baseline pathologist knowledge (the prior) and a prediction online module (the likelihood) that captures a particular pathologist navigation pattern. While optimal parameters for the biologically inspired offline model are calculated using an Expectation‐Maximization strategy, prediction is carried out by a particle filter. Parameters are estimated from several series of actual navigations performed by several pathologists in different virtual slides. The present approach is compared with other conventional prediction methods and decreases the calculated MSE in about a 50% for the entire group of pathologists. Microsc. Res. Tech., 2010. © 2009 Wiley‐Liss, Inc.     

一个基于Agent实现虚拟企业域间协作的框架

国内外关于虚拟企业协作的研究往往忽略了域间、域内协作的差别，片面地采用单一方法来解决虚拟企业复杂的协作问题。在分析了Agent机制适用且仅适用于实现域间协作的原因后，提出了一个基于Agent实现虚拟企业域间协作的框架，旨在解决域间协作前的服务信息登记、伙伴选择，以及协作中伙伴间的交互问题。同时，论述了框架的基本思路、关键策略、协作时Agent的基本交互方式，以及框架在自行研发的两套基于工作流的协作系统之间的实际应用。该框架使企业既能继承原有管理系统，又能实现与其他异构系统之间的协作。     

Optimal artificial fish swarm algorithm for the field calibration on marine navigation

With the rapid development of the optic gyrocompass in aerospace and marine navigation systems, as well as the characteristics of the long-running navigation system which are utilized in this study has created unique developments in the field of marine navigation. It is necessary to re-calibrate the inertial measurement unit (IMU) parameters for maintaining the accuracy and reliability of the system. However, the conventional system re-calibration method needs to disassemble the system and move back to the indoor laboratory with high precision turntable, which is costly and has a heavy workload. This study proposes a novel calibration method by using the optimal artificial fish swarm algorithm (AFSA) on a vehicle aided by a computer. The algorithmic principle is described in detail, and the results obtained from both the simulation and the navigation experiments show the proposed calibration method can meet the calibration accuracy and reliability requirements of the marine gyrocompass.     

机床进给系统摩擦特性分析及改善措施研究

在建立机床进给系统动力学模型的基础上,分析了不同的摩擦特性下引起系统振荡的主要原因,为了解决超精密进给中的振荡问题,提出二级进给策略提高系统的综合刚度和采用导轨软带改善摩擦因素与速度的关系。最后通过试验证实：应用所提出的改善措施,在5 000 N载荷下进给的控制精度达到10 nm。     

Selection of Measured Signals in the Navigation Measuring Complex

To increase accuracy of navigation parameters,a perspective measuring complex with intellectual components is developed.Conception of synthesis optimal structure of the measuring complex is realized basing on a selective method using principles of the functional systems.Selection of measured information is finished by original numeric criterion of observation level of state vector components.Prediction is realized by algorithm of self-organization that makes synthesis of the optimal complication.Therefore mechanism of self-regulation is realized and accuracy of the selective navigation complex is increased.     

Improving unmanned ground vehicle navigation by exploiting virtual sensors and multisensor fusion

This paper investigates techniques on improving navigation accuracy using multiple sensors mounted on a mobile platform and exploiting the inherent characteristic of a ground vehicle that does not move along the cross-track and off the ground, often termed nonholonomic constraints (NHC) for car-like vehicles that assume no slip or skid. The forward velocity of the vehicle is obtained using a wheel encoder. The 3D velocity vector becomes observable during the normal moving state of the vehicle by using NHC, which produces one virtual sensor. Another virtual sensor is the zero-velocity update (ZVU) condition of the vehicle; when the condition is true, the 3D velocity vector (which is zero) becomes observable. These observables were employed in an extended Kalman filter (EKF) update to limit the growth of inertial navigation system error. We designed an EKF for data fusion of inertial measurement units, global positioning systems (GPS), and motion constraints (i.e., NHC and ZVU). We analyzed the effects of utilizing these constraints on improving navigation accuracy in stationary and dynamic cases. Our proposed navigation suite provides reliable accuracy for unmanned ground vehicle applications in a GPS-denied environment (e.g., forest canopy and urban canyon).     

Autonomous mobile robot navigation system designed in dynamic environment based on transferable belief model

This paper investigates the possibility of using transferable belief model (TBM) as a promising alternative for the problem of path planning of nonholonomic mobile robot equipped with ultrasonic sensors in an unknown dynamic environment, where the workspace is cluttered with static obstacles and moving obstacles. The concept of the transferable belief model is introduced and used to design a fusion of ultrasonic sensor data. A new strategy for path planning of mobile robot is proposed based on transferable belief model. The robot’s path is controlled using proposed navigation strategy that depends on navigation parameters which is modified by TBM pignistic belief value. These parameters are tuned in real time to adjust the path of the robot. A major advantage of the proposed method is that, with detection of the robot’s trapped state by ultrasonic sensor, the navigation law can determine which obstacle is dynamic or static without any previous knowledge, and then select the relevant obstacles for corresponding robot avoidance motion. Simulation is used to illustrate collision detection and path planning.     

基于主动悬架系统车辆的道路友好性

为分析悬架系统对车辆道路友好性的影响,设计出可提高道路友好性的主动悬架系统最优控制器,及可分析基于最优控制策略的主动悬架系统,以及被动悬架系统的道路友好性动态仿真模型,仿真分析得出车辆在两种典型的A、B级路面行驶时,基于最优控制策略的主动悬架系统及被动悬架系统车辆对路面造成的动载荷.利用动态载荷系数、动态载荷应力因子及95百分位综合四次幂力三种典型道路友好性评价指标对两种悬架系统的道路友好性进行分析比较.结果表明,采用动态载荷系数、动态载荷应力因子对悬架系统的道路友好性进行评价时,在A级路面上,主动悬架系统的道路友好性分别是被动悬架系统的1.5、1.6倍;在B级路面上主动悬架系统的道路友好性是被动悬架系统的1.5、2.5倍;采用95百分位综合四次幂力指标评价两种悬架系统的道路友好性时,在A级路面上,两种悬架系统的道路友好性相差无几;在B级路面上主动悬架系统的道路友好性比被动悬架系统提高2.5倍.因此,具有合理控制参数的基于最优控制策略的主动悬架系统可提高重型车辆的道路友好性.     

Soft X‐ray spectromicroscopy for speciation,quantitation and nano‐eco‐toxicology of nanomaterials

There is a critical need for methods that provide simultaneous detection, identification, quantitation and visualization of nanomaterials at their interface with biological and environmental systems. The approach should allow speciation as well as elemental analysis. Using the intrinsic X‐ray absorption properties, soft X‐ray scanning transmission X‐ray spectromicroscopy (STXM) allows characterization and imaging of a broad range of nanomaterials, including metals, oxides and organic materials, and at the same time is able to provide detailed mapping of biological components. Thus, STXM offers considerable potential for application to research on nanomaterials in biology and the environment. The potential and limitations of STXM in this context are discussed using a range of examples, focusing on the interaction of nanomaterials with microbial cells, biofilms and extracellular polymers. The studies outlined include speciation and mapping of metal‐containing nanomaterials (Ti, Ni, Cu) and carbon‐based nanomaterials (multiwalled carbon nanotubes, C₆₀ fullerene). The benefits of X‐ray fluorescence detection in soft X‐ray STXM are illustrated with a study of low levels of Ni in a natural river biofilm.     

High accuracy navigation information estimation for inertial system using the multi-model EKF fusing adams explicit formula applied to underwater gliders

The underwater navigation system, mainly consisting of MEMS inertial sensors, is a key technology for the wide application of underwater gliders and plays an important role in achieving high accuracy navigation and positioning for a long time of period. However, the navigation errors will accumulate over time because of the inherent errors of inertial sensors, especially for MEMS grade IMU (Inertial Measurement Unit) generally used in gliders. The dead reckoning module is added to compensate the errors. In the complicated underwater environment, the performance of MEMS sensors is degraded sharply and the errors will become much larger. It is difficult to establish the accurate and fixed error model for the inertial sensor. Therefore, it is very hard to improve the accuracy of navigation information calculated by sensors. In order to solve the problem mentioned, the more suitable filter which integrates the multi-model method with an EKF approach can be designed according to different error models to give the optimal estimation for the state. The key parameters of error models can be used to determine the corresponding filter. The Adams explicit formula which has an advantage of high precision prediction is simultaneously fused into the above filter to achieve the much more improvement in attitudes estimation accuracy. The proposed algorithm has been proved through theory analyses and has been tested by both vehicle experiments and lake trials. Results show that the proposed method has better accuracy and effectiveness in terms of attitudes estimation compared with other methods mentioned in the paper for inertial navigation applied to underwater gliders.     

High-precision assembly automation based on robot compliance

Industrial robots can be made compliant to the environment when the control loop gains are reduced, creating a so-called soft servo capability. This allows industrial robots to be used for assemblies with limited contact requirements. In this paper, we propose an assembly method using soft servo to perform certain assembly tasks where part location errors typically require the use of force control or remote center of compliance (RCC) methods. A typical industrial application, valve body assembly, was used to validate the developed method. This assembly was chosen because it is simple, yet requires compliance in all directions. Lab experiments were performed and the assembly operations were consistently successful enough to show that the developed soft servo strategy can perform certain assembly tasks with small part location errors. Therefore, the soft servo strategy may open a new door for low-cost industrial assembly. Experiments with force control were also performed to compare the performance between soft servo and force control. We found that the force control method is much more sensitive to environmental contact, that the contact forces can be controlled directly, and that greater part location errors can be tolerated. Conversely, assembly with soft servo may either fail to assemble the parts or generate bigger contact forces than allowed. Thus, applications of soft servo are more limited while force control can be successfully used in most all applications. Further investigation is needed to determine the practical industrial use of soft servo for particular types of precision assembly.     

A method for indoor navigation based on magnetic beacons using smartphones and tablets

Outdoor navigation using GPS receivers installed in various types of consumer electronics devices, especially smartphones and tablet computers has become very common. However, indoor navigation can be problematic as GPS signals are blocked by ceilings and building walls and accuracy is on the order of building dimensions. In present work we propose using an array of magnetic beacons for localizing a receiver equipped with a magnetic sensor. A smartphone or a tablet computer with an internal magnetometer can be employed as a receiver. Exploiting smartphones and tablets for indoor navigation is a great advantage when considering convenience, simplicity and low cost. The navigation area is covered by magnetic beacons deployed in known locations. Each beacon generates an AC magnetic field with a unique signature enabling the receiver to distinguish between beacons. The signature may feature a specific single frequency tone, a combination of frequencies, or any other modulated signal. A software application running on the receiver enables self-localization by means of detection and identification of the nearest beacon. A system prototype has been developed and used to test the proposed method in field conditions. Experimental results show successful localization, which paves the way for a full scale development of an effective indoor navigation system. The good results together with simple implementation make the proposed method attractive for a wide range of indoor localization applications, including: pedestrian and robot navigation, inbuilding rescue missions, vision impaired assistance, and location aware services, just to mention a few.     

基于原子干涉技术的水下重力辅助导航研究展望

重力辅助惯性导航是当前水下潜航器导航定位研究的热点和前沿问题,有望成为下一代水下高精度导航系统发展的重要方向。首先,介绍了水下重力信息对于校正惯导系统误差的重要性,阐述了水下重力辅助惯性导航的基本原理与技术内涵;然后,从无图匹配、有图匹配等不同发展阶段,总结了基于传统相对重力仪的水下重力辅助导航的研究现状及发展趋势;进一步分析了下一代水下自主导航系统对高精度绝对重力测量技术的需求,梳理并讨论了基于原子干涉重力测量技术的最新发展及应用状况,展望了原子干涉重力测量技术在水下惯性导航领域的应用前景并总结了仍需解决的关键技术;最后,给出了我国重力辅助导航研究存在的不足及发展建议。     

Friction and wear effects on a micro/nano‐scale

In this paper are described tribological effects which can be found in micro‐tribological systems, and in those macro‐systems which can be analysed by micro‐methods, e.g., by atomic force microscopy (AFM) or related methods. Micro‐tribology systems have friction contacts with loads in the micro/nano‐newton range and/or dimensions in the micro/nanometre range. Experiments on the micro/nano‐scale should be easier to explain by theoretical modelling due to their simpler system structure. An example is discussed of adhesion and friction measurements between AFM tips and clean, flat, solid surfaces in ultra‐high vacuum, which shows some of the special aspects of micro/nano‐tribology. Surprising friction characteristics on surfaces with an artificial micro‐structure can be explained by skilled and careful topographical analysis of the friction path with an AFM. In micro‐sensor contacts, ‘single wear events’ can be detected using AFM analysis of the contact region. For ceramic compounds, different friction levels for the components of the material can be found. The problems, difficulties, and dangers of misinterpretation are also discussed.     

Real-time discrete suboptimal control for systems with input and state delays: Experimental tests on a dehydration process

This article presents a suboptimal control strategy with finite horizon for affine nonlinear discrete systems with both state and input delays. The Dynamic Programming Approach is used to obtain the suboptimal control sequence, but in order to avoid the computation of the Bellman functional, a numerical approximation of this function is proposed in every step. The feasibility of our proposal is demonstrated via an experimental test on a dehydration process and the obtained results show a good performance and behavior of this process. Then in order to demonstrate the benefits of using this kind of control strategy, the results are compared with a non optimal control strategy, particularly with respect to results produced by an industrial Proportional Integral Derivative (PID) Honeywell controller, which is tuned using the Ziegler-Nichols method.     

Real-time and label-free detection of chloramphenicol residues with specific molecular interaction

Molecular measurements with specific or non-specific molecular interaction are usually reported by using different methods. This paper shows a method for small-molecular label-free measurements in real time with specific and non-specific molecular interaction based on surface plasmon resonance. The quantitative measurement of glucose with non-specific molecular interaction was performed simply to validate our self-built angle-dependent surface plasmon resonance system, which showed a good sensitivity and stability, such as that of Fourier transform infrared spectrometer. As application, we present the measurement of chloramphenicol residues with specific molecular interaction employing an indirect competitive immunoreaction by using the same surface plasmon resonance system with a limit of detection about 0.5 ng mL⁻¹, which shows a potential application for food safety.     

Multi-agent decision fusion for motor fault diagnosis

Improvement of recognition rate is ultimate aim for fault diagnosis researchers using pattern recognition techniques. However, the unique recognition method can only recognise a limited classification capability which is insufficient for real-life application. An ongoing strategy is the decision fusion techniques. In order to avoid the shortage of single information source coupled with unique decision method, a new approach is required to obtain better results. This paper proposes a decision fusion system for fault diagnosis, which integrates data sources from different types of sensors and decisions of multiple classifiers. First, non-commensurate sensor data sets are combined using an improved sensor fusion method at a decision level by using relativity theory. The generated decision vectors are then selected based on correlation measure of classifiers in order to find an optimal sequence of classifiers fusion, which can lead to the best fusion performance. Finally, multi-agent classifiers fusion algorithm is employed as the core of the whole fault diagnosis system. The efficiency of the proposed system was demonstrated through fault diagnosis of induction motors. The experimental results show that this system can lead to super performance when compared with the best individual classifier with single-source data.     

Substructuring including interface reduction for the efficient vibro-acoustic simulation of fluid-filled piping systems

The operation of pumps and valves leads to strong acoustic excitation in fluid-filled piping systems. Efficient substructuring and model order reduction strategies are required for the sound prediction in piping systems, and in order to reduce the sound transmission to attached components, such as the floor panel in vehicles, for example. This research presents a finite element based automatic substructuring and component mode synthesis technique, which is a combination of an extended Craig–Bampton method for fluid–structure coupled piping systems and a novel, consecutive interface reduction. Hereby, the remaining interface degrees of freedom between different substructures are further reduced using appropriate Ritz vectors. The proposed model order reduction strategy accelerates the computation of transfer functions in fluid-filled extended piping systems. In order to validate the simulation results, experimental results are obtained by a hydraulic test bench for dynamic measurements, where fluid pulsation is induced by piezo-driven transducers. The observed fluid–structure interaction phenomena correspond to the predictions by the proposed computation approach.     

高灵敏度EMCCD导航相机的设计

导航相机是深空探测领域中关键的导航敏感部件,本文通过提高导航相机的灵敏度来提高导航相机的综合性能,特别是提高时间分辨率,解决高动态条件下的目标探测问题。首先,根据导航相机的工作模式和EMCCD的性能特点,分析了影响导航相机成像质量的多个因素,建立了目标信噪比理论分析模型;然后,在理论计算基础上,重点研究EMCCD导航相机的样机设计技术,说明了EMCCD高频高幅驱动、模拟前端设计、TEC真空制冷、时序控制与数据处理等关键技术的实现方法;最后,介绍了相关实验工作,并分析实验数据。实验结果表明:样机最大目标信噪比在倍增增益M=10时达到68.6dB,在口径13mm条件下,可在积分时间1ms内实现对月球成像。基本满足深空探测导航相机高动态条件下短积分时间成像的要求。     

An integrated fuzzy approach for the selection of manufacturing technologies

In this paper, an integrated decision support system is developed, which employs fuzzy techniques to assist decision-makers in choosing an optimal solution from alternative manufacturing options in an uncertain environment. The integrated approach incorporates different justification methods (e.g., strategic, economic, and analytic evaluations) for assessing tangible benefits, like cost, and intangible benefits, like quality, of different alternatives by a fuzzy multi-criteria decision-making method. As an illustrative example, selection of different advanced manufacturing technologies has been demonstrated by using the proposed methodology. The proposed concept will greatly reduce conflicts between tangible and intangible factors, and enhance the process of identification, interpretation, and diagnosis of the value of complex manufacturing and engineering systems.