Sökresultat

This thesis investigates the topic of joint positioning and radio channel estimation and prediction. Both positioning and radio channel estimation have a long history of research with many publications but the combination of the two has so far at large been left unexplored. The reason for studying this topic is twofold: improvement of positioning and improvement of radio channel prediction. Positi

Time synchronisation is crucial for distributed systems, and particularly for Wireless Sensor Networks (WSNs), where each node is executing concurrent operations to achieve a real-time objective. However, synchronisation is quite difficult to achieve in WSNs, due to the unpredictable deployment conditions and to physical effects like thermal stress, that cause drifts in the local node clocks. As a

We propose a distributed optimization algorithm for mixed L_1/L_2-norm optimization based on accelerated gradient methods using dual decomposition. The algorithm achieves convergence rate O(1/k^2), where k is the iteration number, which significantly improves the convergence rates of existing duality-based distributed optimization algorithms that achieve O(1/k). The performance of the developed al

Low-complex and low power non-coherent energy detector (ED) is interesting for low data rate impulse radio (IR) ultra wideband (UWB) systems but, compared to coherent receivers, it suffers from a loss in performance due to low signal-to-noise ratio (SNR) at the detector. In addition, the performance of an ED strongly depends on the integration interval (window size) of the integrator and the window

In manipulation tasks, motion trajectories are characterized by a set of key phases (i.e., motion primitives). It is therefore important to learn the motion primitives embedded in such tasks from a complete demonstration. In this paper, we propose a core framework that autonomously segments motion trajectories to support the learning of motion primitives. For this purpose, a set of segmentation po

Despite recent attempts to relax the phase-noise demands on voltage-controlled oscillators (VCOs) for cellular communications [1], mainstream radios require harmonic VCOs capable of a very low phase noise with moderate power consumption, associated to a large tuning range (TR) and a high insensitivity to interfering signals. Ideally, the TR should be in excess of one octave, since this allows the

We perform a minimum distance analysis of a class of two-dimensional intersymbol interference (ISI) channels applicable to multitrack magnetic recording and orthogonal frequency division multiplex transmission systems. Exact minimum distance for a wide class of ISI responses is derived. The fundamental analytical technique is to transform the channel into an equivalent minimum phase channel. The r

The popularity of Open Source Software (OSS) has increased the interest in using it in safety critical applications. The aim of this study is to review research carried out on usage of open source code in development of safety-critical software and systems. We conducted a systematic mapping study through searches in library databases and manual identification of articles from open source conferenc

This paper suggests an extension of an existing, clinically evaluated, closed-loop drug delivery system for hypnotic depth control using propofol. The extension introduces closed-loop administration of the analgesic drug remifentanil, thus forming a multiple input–single output (MISO) control system. Remifentanil acts and is metabolized at a significantly faster time scale than propofol. Direct co

The management of resources among competing QoS-aware applications is often solved by a resource manager (RM) that assigns both the resources and the application service levels. However, this approach requires all applications to inform the RM of the available service levels. Then, the RM has to maximize the "overall quality" by comparing service levels of different applications which are not nece

Abstract in UndeterminedThis paper presents a filtering ADC for the LTE communication standard, where a second-order Delta-Sigma modulator (DSM) is incorporated into the third-order Chebychev channel-select filter (CSF) of the radio receiver. The CSF introduces an additional third-order suppression of both thermal and quantization DSM noise, while the CSF transfer function is maintained. A design

Two main topics are considered in this thesis: Machining with industrial robot manipulators and optimal motion control of robots and vehicles. The motivation for research on the first subject is the need for flexible and accurate production processes employing industrial robots as their main component. The challenge to overcome here is to achieve high-accuracy machining solutions, in spite of the

This paper presents a 2.45 GHz wake-up receiver front-end intended for use in sensor networks, and is designed to receive data modulated with on-off-keying. Manufactured in 65 nm CMOS it employs an uncertain IF structure with three phase passive mixer and high gain amplifier chain. With the modulation frequency response tailored to the detector behaviour, it achieves a sensitivity of -88 dBm at BE

Abstract in UndeterminedYou may think that your requirements engineering process is fairly limited and currently not too complex to manage. Or you may be right in the middle of a storm of requirements where it is impossible to manage even the most important ones comprehensively. If you are in the former situation, it may be dangerous to relax as many successful software-intensive products have a t

Industrial robots are traditionally programmed using only the internal joint position sensors, in a sense leaving the robot blind and numb. Using external sensors, such as cameras and force sensors, allows the robot to detect the existence and position of objects in an unstructured environment, and to handle contact situations not possible using only position control. This thesis presents work on

Force sensing provides robots the capability to accomplish tasks where physical interaction with the environment is required, such as assembly. Small position uncertainties can then be corrected for by sensing the contact forces. This thesis considers the problem of force-controlled assembly, including how tasks can be specified in a simple and intuitive way and how robust task execution under unc

An all digital phase-locked loop (ADPLL) has been implemented in a 90-nm CMOS process. It uses a phase-frequency detector (PFD) connected to two time-to-digital converters (TDC). To save power the TDCs use delay line cells with uneven delay time. During frequency acquisition an automatic tuning bank controller selects active bank of the digitally controlled oscillator (DCO), which features three s

Two mixed-phase precipitation events were observed on 21 September and 20 October 2010 over the southern part of Finland during the Light Precipitation Validation Experiment (LPVEx). These events have been simulated using the Weather Research and Forecasting Model coupled with spectral bin microphysics (WRF-SBM). The detailed ice-melting scheme with prognosis of the liquid water fraction during me