Jorge L. Falcó

Robust estimator for non-line-of-sight error mitigation in indoor localization

Indoor localization systems are undoubtedly of interest in many application fields. Like outdoor systems, they suffer from non-line-of-sight (NLOS) errors which hinder their robustness and accuracy. Though many ad hoc techniques have been developed to deal with this problem, unfortunately most of them are not applicable indoors due to the high variability of the environment (movement of furniture and of people, etc.). In this paper, we describe the use of robust regression techniques to detect and reject NLOS measures in a location estimation using multilateration. We show how the least-median-of-squares technique can be used to overcome the effects of NLOS errors, even in environments with little infrastructure, and validate its suitability by comparing it to other methods described in the bibliography. We obtained remarkable results when using it in a real indoor positioning system that works with Bluetooth and ultrasound (BLUPS), even when nearly half the measures suffered from NLOS or other coarse errors.

Location-based services for elderly and disabled people

Many techniques have been developed to perform indoor location. Each strategy has its own advantages and drawbacks, with the application demanding location information the main determinant of the system to be used. In this paper, a system is presented that serves location to innovative services for elderly and disabled people, ranging from alarm and monitoring to support for navigation and leisure. The system uses ZigBee and ultrasound to fulfill the application requirements, differing in this respect from all other existing systems. ZUPS (ZigBee and ultrasound positioning system) provides wide multicell coverage, easy extension, robustness even in crowded scenarios, different levels of precision depending on the users profile and service requirements (from a few centimeters to meters), limited infrastructure requirements, simple calibration, and cost-effectiveness. The system has been evaluated from the technical, functional, and usability standpoints, with satisfactory results, and its suitability has also been demonstrated in a residence for people with disabilities located in Zaragoza, Spain.

Hidden Issues in Deploying an Indoor Location System

Installing indoor location system prototypes yields practical lessons about how to design and deploy future ubiquitous technologies. The design of context-aware technologies has been on many research team agendas since Mark Weiser first described his ubiquitous computing vision. Determining the location of people and objects in indoor environments with a high degree of accuracy is a main technical obstacle to achieving this vision.

Synchronization in wireless sensor networks using Bluetooth

Wireless sensor networks (WSNs) can take advantage of versatility, completeness, and low prices of standard wireless protocols; Bluetooth as we show later is a candidate suitable for WSNs. The fusion of data collected over a WSN is just an evident application of time synchronization. Bringing together these two issues, we find that synchronization using standard protocols poses an important drawback. In this paper, we present a simple method that allows clock synchronization in Bluetooth WSNs, down to few microseconds.

AmI and Deployment Considerations in AAL Services Provision for Elderly Independent Living: The MonAMI Project

The MonAMI project aims to investigate the feasibility of the deployment of open platforms for Ambient Assisted Living (AAL) services provision based on Ambient Intelligence (AmI) and to test user acceptance and the usability of the services. Services were designed to provide support in the areas of environmental control, security, well-being and leisure. These services were installed and evaluated in a Spanish geriatric residence. The participants included elderly persons with disabilities, nursing home care givers and informal carers. The concept of the open platform proved to be satisfactory for the provision of the services in a context aware framework. Furthermore, the usability of the technology was viewed positively and the overall results indicate that this system has the potential to prolong independent living at home for elderly people with disabilities. Deployment was proven successful and awareness of open-platform AAL service delivery was raised in local communities throughout Europe.

DALMA – location aware alarm system for people with disabilities

This paper presents a location aware alarm system developed to give each person greater and safer mobility by automatically detecting risk situations. Location awareness has been possible thanks to an indoors positioning system (IPS) based on Bluetooth and ultrasounds, developed by the authors. The IPS is able to give accuracies of several centimetres, using a reduced infrastructure (6 fixed beacons every 100 m2). The alarm system has been implemented in several stances of a special education school. Preliminary evaluation results show its reliability and usability

Positioning technologies in learning

In the following we discuss how a high precision, indoor positioning system (UNIZAR positioning system) can be part of a general positioning system to fit into different application areas depending on different needs and requirements for precision. Specific focus is put on applications for learning and training contexts. We argue that many innovative user interfaces for learning are based on digital manipulatives, which could be substantially enhanced by positioning augmentation.

Multi-Hop Synchronization at the Application Layer of Wireless and Satellite Networks

Time synchronization is a key issue in wireless and satellite networks; time-stamping collected data, tasks scheduling or efficient communications are just some applications. From all the existing techniques to achieve synchronization, those that work at the MAC layer and can precisely timestamp sync messages are the most accurate. However, working with standard protocols, usually prevents the user from accessing lower layers and consequently reduces accuracy. Receiver-receiver schema improves time-stamping performance because it eliminates the biggest non-deterministic error at the sender side; the medium access time. Nevertheless, utilization of these methods in multi- hop networks usually requires an extra amount of traffic. In this paper we present a method which allows accurate synchronization of large multi-hop networks such as satellite networks working at the application layer while keeping the message exchange to the minimum. Through an exhaustive experimentation, we show the protocols performance and analyze the factors that influence synchronization accuracy the most.

MonAMI: economic impact of mainstream AAL open platform in home care

The MonAMI project was aimed to investigate the feasibility of the deployment of open platforms for Ambient Assisted Living (AAL) services provision and to test user acceptance and the usability of the services. The services were designed to give support in the areas of environmental control, security, and leisure. The concept of the open platform proved to be satisfactory for the provision of the services. The usability of the technology was viewed positively and the overall result indicates that this system has the potential to prolong independent living at home for elderly people with disabilities. Furthermore, business opportunities in environmental control and security are shown.

Guiding support for ‘way-finding' in unknown buildings: design and evaluation

We face the support to finding the way in an unknown building, such as hospital or city-hall for people with special needs (reduced vision, cognitive disabilities, physical disabilities), which forces not only to find the way, but to find the suitable one for specific capacities. Our goal is to enhance accessibility to public services and leisure in an autonomous and easier way. The system design uses building and personal context to find an adequate way to his/her destiny. Then it will guide the person through the way, monitoring the route followed, re-conducting when needed and giving the chance to change destination. This paper shows a brief description of the system and the two evaluation stages performed with their conclusions. A multidisciplinary team with engineers, gerontologists, psychologist and two special education schools are involved in specification, development and evaluation