Alar Kuusik

RFID-based Communications for a Self-Organising Robot Swarm

We investigate the practical questions of building a self-organizing robot swarm, using the iRobot Roomba cleaning robot as an experimental platform. Our goal is to employ self-organization for enhancing the cleaning efficiency of a Roomba swarm. The implementation uses RFID tags both for object and location-based task recognition as well as graffiti- or stigmata-style communication between robots.Easily modifiable rule systems are used for object ontologies and automatic task generation. Long-term planning and central coordination are avoided.

Medical and context data acquisition system for patient home monitoring

Patient remote monitoring has continuously rising importance for aging countries. Computer based assisted living systems are too difficult to handle by elderly people, therefore it has been proposed to extend smart home control or entertainment systems with patient monitoring functionalities. However, such implementations are usually platform and data protocol specific making their extension time consuming and data interpretation complicated. We propose a semantics driven messaging system and agent based software architecture for home telecare that is open for adding any kind of medical or context sensors, either wired or wireless ones. System can be reconfigured during the operation and its output data is highly compatible with eHealth databases. The solution is prototyped.

Radio Resource Management Scheme in NB-IoT Systems

Narrowband Internet of Things (NB-IoT) is the prominent technology that fits the requirements of future IoT networks. However, due to the limited spectrum (i.e., 180 kHz) availability for NB-IoT systems, one of the key issues is how to efficiently use these resources to support massive IoT devices? Furthermore, in NB-IoT, to reduce the computation complexity and to provide coverage extension, the concept of time offset and repetition has been introduced. Considering these new features, the existing resource management schemes are no longer applicable. Moreover, the allocation of frequency band for NB-IoT within LTE band, or as a standalone, might not be synchronous in all the cells, resulting in intercell interference (ICI) from the neighboring cells’ LTE users or NB-IoT users (synchronous case). In this paper, first a theoretical framework for the upper bound on the achievable data rate is formulated in the presence of control channel and repetition factor. From the conducted analysis, it is shown that the maximum achievable data rates are 89.2 Kbps and 92 Kbps for downlink and uplink, respectively. Second, we propose an interference aware resource allocation for NB-IoT by formulating the rate maximization problem considering the overhead of control channels, time offset, and repetition factor. Due to the complexity of finding the globally optimum solution of the formulated problem, a sub-optimal solution with an iterative algorithm based on cooperative approaches is proposed. The proposed algorithm is then evaluated to investigate the impact of repetition factor, time offset and ICI on the NB-IoT data rate, and energy consumption. Furthermore, a detailed comparison between the non-cooperative, cooperative, and optimal scheme (i.e., no repetition) is also presented. It is shown through the simulation results that the cooperative scheme provides up to 8% rate improvement and 17% energy reduction as compared with the non-cooperative scheme.

Wearable system for patient motor condition assessment and training monitoring

In this paper we describe an extendable point of care system for simultaneous motor rehabilitation (post-stroke and -arthroscopy) patient condition assessment and patient safety observations. Electronic linear and angular accelerometer sensors attached to the human upper or lower limbs gather information about performed therapeutic exercises. The measurement data processing of the vital sign sensors and accelerometers is done in the health hub device in real time with the patient feedback. The movement correctness evaluation and gait analysis is done with ANARX neural network based models. The system is implemented and tested. The evaluation of the test results is presented.

Bioimpedance monitoring with improved accuracy using three-level stimulus

Operation principles, modeling, and practical design of a novel system for bioimpedance (BI) measurement and monitoring are introduced in this paper. The system employs excitation and reference signals in a form of three-level rectangular waveforms with specially shortened duty cycles for eliminating some higher harmonics from the measured response. It enables to decrease systematic errors and ensures simplicity and power efficiency for wearable devices at the same time. The system is designed as a four-channel instrument, while both, the analog and digital approaches are discussed.

A Digital Multichannel Bioimpedance Analyser: Signal Processing Task and its Solution

Measurement of electrical bioimpedance enables to characterize a state of tissues/organs, to get diagnostic images, to find hemodynamical parameters, etc. In this paper we consider a digital multichannel bioimpedance analyser developed for monitoring of the state of a working heart. The signal-processing task, which must be solved in this analyser, is described and some proposed alternative algorithmic and hardware solutions of this task are considered and compared

Real-time data streaming for functionally improved eHealth solutions

Present eHealth solutions developed for EHRs lack for motivation of use for competing healthcare enterprises and attraction for citizens. Proposed Universal Health Repositories supporting both clinical and home-measurement data related to telemedicine and wellness applications may force both institutions and individuals for active data sharing and exchange. However, HL7 protocol based communication solutions and installable software traditionally used in professional healthcare does not suit well for rapidly changing user driven application field. In the paper we describe a developed mobile data streaming and completely web based real-time access solution. The software has been developed for demonstrating novel services within an existing nation-wide eHealth system. The long term goal deploying similar applications is engage more citizens and healthcare enterprises to use eHealth services.

Semantic formal reasoning solution for personalized home telecare

Modern home telehealth care systems should support personalized data processing and environment monitoring for context awareness. Semantic rule based approach has been proposed by many authors to overcome problems coming from large amounts of location and patient-specific, typically inconsistent monitoring data. However, existing solutions just present proof of concept and do not address implementation feasibility and practical issues of eHealth system compatibility. We describe a telehealth care solution employing Prolog programs based on defeasible rule-based reasoning and SNOMED medical terminology system deployed in home digital TV receivers.

An energy efficient wearable tissue monitor

Tissue transplantation is often crucial for victims of accidents. Monitoring the healing process in tissue transplants during the first hours and days is a key factor to successful reconstructive surgery. Visual inspection is the preferred method today with two serious flaws – lack of qualified personnel, and uncertainty in interpretation of observations, which could lead to late discovery of problems in transplanted muscle flaps. Tissue impedance reflects these changes in tissue state as the level of reperfusion and development of edema, which characterize the revivability or resuscitation of the tissue after transplantation. A multi-channel device for monitoring of the tissue impedance at different frequencies is proposed. By definition, bioimpedance is complex parameter of the tissue under examination, and a measure of opposition to the sinusoidal alternating electric current. Correct sinusoidal excitation is computationally and energetically inefficient to use. Limits to available energy resources and processing power in wearable electronics require more robust means, while preserving accuracy of the signal. Also the speed of conventional discrete Fourier transform based algorithms need to be increased.

Synchronization algorithm for RFID-reader and its implementation

An algorithm for synchronization of a decoder of a RFID receiver has been proposed, implemented and evaluated, by experimental setup. The solution can be used for UHF RFID (e.g. ISO18000-6 and EPC gen 2) readers using FM0, bi-phase or differential Manchester decoding. Goal of the proposed solution is the improved decoding of the received data in the presence of noise (so by using less power or working at longer distance) by innovative synchronization techniques. Synchronization problem (and challenge) is caused by non-precise timing of the binary signals sent by simple passive RFID-tags. Hardware prototype has been developed for testing and evaluating of the RFID-reader synchronization algorithm for decoding of the binary information. The developed algorithm has been implemented as C/C++ code for DSP and can be evaluated, benchmarked and developed further, with real-world experimental data log files acquired with the developed hardware setup (also on PC). The proposed algorithm is based on the finding of the best correlation of the expected binary preamble (header) waveform of the communication packet with corresponding part of the received noisy signal, as used in other known solutions, with variation of the possibly expected timing parameters, e.g by using matched correlation (FIR) filter-banks. The idea of the proposed solution is to use additionally to maximum correlation of the received signal with the reference preamble waveform also the “quadrature” version of the reference (derived from the ideal preamble) signal, as the “quadrature” correlation has at the best match clear zero value and has change around this “zero” point. So using this additional “Q” correlation channel gives the opportunity to find the exact timing base (“bit duration”) more precisely. The proposed algorithm and the results of the evaluation of the solution with real-world data are described. Also, potential future developments of the solution are discussed.