Fine-grained indoor positioning and tracking systems

Indoor positioning has attracted considerable attention for decades due to the increasing demands for location based services. In the past years, although numerous methods have been proposed for indoor positioning, it is still challenging to find a convincing solution that combines high positioning accuracy and ease of deployment. Radio-based indoor positioning has emerged as a dominant method due to its ubiquitousness, especially for WiFi. RSSI (Received Signal Strength Indicator) has been investigated in the area of indoor positioning for decades. However, it is prone to multipath propagation and hence fingerprinting has become the most commonly used method for indoor positioning using RSSI. The drawback of fingerprinting is that it requires intensive labour efforts to calibrate the radio map prior to experiments, which makes the deployment of the positioning system very time consuming. Using time information as another way for radio-based indoor positioning is challenged by time synchronization among anchor nodes and timestamp accuracy. Besides radio-based positioning methods, intensive research has been conducted to make use of inertial sensors for indoor tracking due to the fast developments of smartphones. However, these methods are normally prone to accumulative errors and might not be available for some applications, such as passive positioning. This thesis focuses on network-based indoor positioning and tracking systems, mainly for passive positioning, which does not require the participation of targets in the positioning process. To achieve high positioning accuracy, we work on some information of radio signals from physical-layer processing, such as timestamps and channel information. The contributions in this thesis can be divided into two parts: time-based positioning and channel information based positioning. First, for time-based indoor positioning (especially for narrow-band signals), we address challenges for compensating synchronization offsets among anchor nodes, designing timestamps with high resolution, and developing accurate positioning methods. Second, we work on range-based positioning methods with channel information to passively locate and track WiFi targets. Targeting less efforts for deployment, we work on range-based methods, which require much less calibration efforts than fingerprinting. By designing some novel enhanced methods for both ranging and positioning (including trilateration for stationary targets and particle filter for mobile targets), we are able to locate WiFi targets with high accuracy solely relying on radio signals and our proposed enhanced particle filter significantly outperforms the other commonly used range-based positioning algorithms, e.g., a traditional particle filter, extended Kalman filter and trilateration algorithms. In addition to using radio signals for passive positioning, we propose a second enhanced particle filter for active positioning to fuse inertial sensor and channel information to track indoor targets, which achieves higher tracking accuracy than tracking methods solely relying on either radio signals or inertial sensors.

Sural nerve conduction studies using ultrasound-guided needle positioning: Influence of age and recording location.

INTRODUCTION The aim of this study was to compare orthodromic sural nerve conduction study (NCS) results using ultrasound-guided needle positioning (USNP) to surface electrode recordings. METHODS 51 healthy subjects aged 24 - 80 years, divided into 5 age groups, were examined. Electrical stimuli were applied behind the lateral malleolus. Sensory nerve action potentials (SNAPs) were recorded 8 and 15 cm proximally with surface and needle electrodes. RESULTS Mean SNAP amplitudes in µV (surface/needle electrodes) averaged 12.7 (SD 7.6)/40.6 (SD 20.8), P<0.001, for subjects aged 20-29 years, and 5.0 (SD 2.4)/19.8 (SD 9.8), P<0.01, for subjects aged > 60 years. SNAP amplitudes were smaller at the proximal recording location. DISCUSSION NCS using USNP yield higher amplitude responses than surface electrodes in all age groups at all recording sites. SNAP amplitudes are smaller at proximal recording locations due to sural nerve branching. This article is protected by copyright. All rights reserved.

Institutional Repository Workflow from Initial Inquiry to Repository Upload

A workflow flowchart on the verification steps involved in preparation to uploading assets to the University of Connecticut's institutional repository (http://digitalcommons.uconn.edu). This flowchart is geared towards assisting subject liaisons who also serve as series administrators for UConn@DigitalCommons.

Google Analytics & CONTENTdm: Harness Up Your Repository Metrics

A demonstration of the installation and use of Google Analytics with CONTENTdm in order to better gather metrics and insight into both general and specific online traffic across such digital repositories. Issues addressed will include collection-level traffic, digital object-level traffic, general site referrals to the repository, specific referrals to the repository, search engine referrals, user keywords, traffic occurring inside and/or outside an institution’s own network, reporting options.

Digital repository implementation: a toolbox for streamlined success

Purpose – The purpose of this paper is to describe the tools and strategies that were employed by C/W MARS to successfully develop and implement the Digital Treasures digital repository. Design/methodology/approach – This paper outlines the planning and subsequent technical issues that arise when implementing a digitization project on the scale of the large, multi-type, automated library network. Workflow solutions addressed include synchronous online metadata record submissions from multiple library sources and the delivery of collection-level use statistics to participating library administrators. The importance of standards-based descriptive metadata and the role of project collaboration are also discussed. Findings – From the time of its initial planning, the Digital Treasures repository was fully implemented in six months. The discernable and statistically quantified online discovery and access of actual digital objects greatly assisted libraries unsure of their own staffing costs/benefits to join the repository. Originality/value – This case study may serve as a possible example of initial planning, workflow and final implementation strategies for new repositories in both the general and library consortium environment. Keywords – Digital repositories, Library networks, Data management. Paper type – Case study