The aim of this project is to acquire gas data using an Arduino microcontroller. This project is part of a bigger project called The electronic nose where mechanical, thermal, electrical, electronic and software parts work together. It is the continuation of a project handled before where mainly the mechanical, thermal and electrical parts were done.   The whole e-Nose project is divided in 4 main subcategories: general mechanical structure, thermal and piston electric circuit, gas sensors and software. My work will be focused in the last two subcategories of the general project.   The sample to be measured is placed inside of a moving cylinder, which will lift up the sample reaching near the sensors and warming it using a thermal resistance, to release more odor. That is where the sensors act, synchronized with the piston, will get the data through the Arduino and sends it to the computer to be analysed. The sensors will be activated using an Arduino Mega 2560 and transferred to the computer to be analysed with MatLab.   To control the measurement, a push button, a LCD display and a LED will be placed; having like this a full control of the project and an easy interface for the user. Six gas sensors will be used, which will be enough to be able to differentiate between different kind of gases. With such variety it is possible to categorize between combustible gas (methane, propane, LPG etc.), NH3, alcohol and more gases.   The e-Nose will be able to measure different gases in more than ways depending on the program we choose. For a more accurate response, more sensors would be needed using a sensor fusion method or more accurate sensors.

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This thesis presents contributions in the field of satellite navigation with a focus on array processing and related implementation issues. For readers not familiar with GNSS, it also includes a brief overview of satellite navigation.Compared to the state of the art only ten years ago, modern GNSS receivers are very capable. One reason for this improvement is advances in the semiconductor industry that have increased both the available processing power and the energy efficiency. An active research community have also made important contributions resulting in more sophisticated algorithms. To improve receiver performance even further, auxiliary sensors such as gyros and accelerometers are becoming increasingly common. A related option involves using an antenna with several physical elements. This is known as an antenna array and is often used for radar, sonar and telecommunication applications. Array processing can also be used for GNSS and as such it is the primary focus of this thesis. An array allows for exploration of the spatial domain, in other words a receiver that may differentiate between signals depending on the direction of arrival. For GNSS, where interference and multipath (signal reflection off, for example, buildings or the ground) may be significant sources of error, this is an attractive solution. Although array processing have been the subject of extensive research efforts within other fields, there are several remaining issues with regards to how these techniques can be implemented in a GNSS receiver.With regards to array processing there are also properties unique to GNSS, such as multiple signal sources at known positions, that have not been explored sufficiently in previous efforts. In this thesis we show how these properties can be exploited to improve receiver performance in dynamic scenarios. In short, the orientation of the antenna platform is estimated accurately (typical variance around 1°) using beamforming techniques. This information is then used to achieve a better estimate of the radio environment by allowing for longer integration periods when estimating the covariance matrices. A better estimate of the covariance matrices directly translates into improved receiver performance, especially so in areas of moderate levels of multipath/interference.Further, a method to calibrate GNSS array antennas using real signals is investigated in detail. Instead of resorting to electromagnetic simulations that requires precise knowledge about the antenna and installation factors, or RF chamber measurement that is expensive, it is shown how the array antenna can be calibrated using live signals. The accuracy of the resulting model is verified using real data.Also, the first implementation of an RF record and replay system is presented. With such a system data can be recorded in a specific environment, generally a time consuming task, and later played back into the antenna input of any GNSS receiver. Such systems are nowadays commercially available and have proven very useful for testing and validation of GNSS receivers. Throughout the thesis, the required receiver architecture and practical viability of the proposed algorithms are considered. / Godkänd; 2011; 20110217 (staffan); DISPUTATION Opponent: Associate Professor Gonzalo Seco Granados, Universitat Autònoma de Barcelona, Barcelona, Spain Ordförande: Professor Dennis Akos, Institutionen för system- och rymdteknik, Luleå tekniska universitet Tid: Torsdag den 7 april 2011, kl 13.00 Plats: A117, Luleå tekniska universitet

This thesis presents the foundations of a method for estimating fibre properties of pulp suitable for online application in the pulp and paper industry. In the pulp and paper industry, increased efficiency and greater paper quality control are two of the industry's main objectives. It is proposed that online fibre property measurements are a means of achieving progress in both of these objectives. Optical based systems that provide valuable geometric data on the fibres and other pulp characteristics are commercially available. However, measurements of the elastic properties of the fibres are not currently implemented using these systems. To fill this gap an ultrasound based system for measuring the elastic properties of the wood fibres in pulp is proposed. Ultrasound propagation depends on the elastic properties of a solid. Hence attenuation measurements from suspensions of fibres depend on their elastic properties. The method is based on solving the inverse problem where the output is known and the objective is to establish the inputs. In this case, attenuation is measured and a model of attenuation based on ultrasound scattering is developed. A search algorithm is used for finding elastic properties that minimize the error between the model and measured attenuation. The results of the search are estimates of the elastic properties of the fibres in suspension. The results show resonance peaks in the attenuation, in the frequency region tested, for fibres with radii of the order of 10 microns. These peaks are found in both the measured and modelled attenuation spectra. Further investigation of these resonances suggests that they are due to modes of vibration in the fibre where the fibre modelled as an infinitely long cylinder. These resonances are shown to aid in the identification of the elastic properties. The attenuation is found to depend heavily on the geometry of the fibres. Hence fibre geometry, which can be obtained from online optical fibre measurement system, provides the key to extracting the elastic properties from the attenuation signal. Studies are also carried out on the effect of viscosity on attenuation as well as the differences in attenuation between hollow and solid synthetic fibres in suspensions. The measurement method is also applied to hardwood and softwood Kraft pulps. The results of these studies show that using the model derived in the thesis and attenuation measurements, estimates of the elastic properties can be obtained. The elastic property estimates for synthetic fibres agree well with values from other methods. The elastic property estimates for pulps require further validation due to the difficulty in comparing between different testing methods and different types of pulp. The conclusions, based on the work so far and under three realisable conditions, are that the shear modulus and the transverse Young's modulus of pulp fibres can be measured. Once these conditions are met a system based on this method can be implemented. By doing this the industry would benefit from the increase in paper quality control and energy saving such system could provide. / Godkänd; 2009; 20090507 (aitomaki); DISPUTATION Ämnesområde: Industriell elektronik/Industrial Electronics Opponent: Professor Richard Challis, the University of Nottingham, United Kingdom Ordförande: Teknologie doktor Torbjörn Löfqvist, Luleå tekniska universitet Tid: Onsdag den 3 juni 2009, kl 10.00 Plats: D770, Luleå tekniska universitet

The idea of district heating is to heat up a whole district from a central source through a distribution network. The heat is extracted by heat exchangers and the water is then subsequently returned to the central source. The heat exchange between the district heating network and the building occurs in district heating substations. Heat meters are located in such substations and are divided into two main categories depending on their heat energy estimation frequency modes. Which are either constant or flow rate dependent. The Swedish district heating industry is a business with revenue of approximately 19.8 billion SEK (as of the year 2002). Considering an error of 1% in energy delivered, that is a loss of 198 million SEK, which justifies the current research. The accuracy in heat measurement for billing purposes is then one of the major reasons for conducting this research. Few studies have been done in this area. A Swedish study shows that the major causes of the errors are: flow meters, temperature sensors, integrating units, lightning, control systems, valves, leaks in heat exchangers and the dynamic heat demand imposed on the district heating substation. I have chosen to study the heat measurement errors due to dynamic load imposed on the district heating substation because they are the least investigated and presumably account for a substantial portion of the total error. I have delimited my research area to include single family houses, since the effects of dynamic heat load on heat metering are more important in this kind of dwelling. A major tool in the investigation has been simulations based on a Simulink model, of a district heating substation and a house. For this purpose, the simulation model has been extended to handle new heat measurement strategies. A district heating laboratory was built at Luleå University of Technology to test not only the accuracy of different heat measurement algorithms but also control and diagnosis methods. Based on analysis of the measurement strategies, an adaptive algorithm and a feed-forward method are proposed in this thesis to reduce the heat measurement errors due to the dynamic heat demand imposed on the substation. Simulations conducted show that the adaptive algorithm has a higher measurement accuracy than both kinds of existing heat meters. The feed-forward method has the highest measurement accuracy compared to both kinds of existing heat meters and the adaptive algorithm. / Godkänd; 2006; 20061116 (pafi) / Fjärrvärme

The research presented in this thesis discusses an electromagnetic (EM) analysis tool which is based on the partial element equivalent circuit (PEEC) method and is appropriate for combined EM and circuit simulations especially power electronics applications. EM analysis is important to ensure that a system will not affect the correct operation of other devices nor cause interference between various electrical systems. In power electronic applications, the increased switching speed can cause voltage overshoots, unbalanced current share between semiconductor modules, and unwanted resonances. Therefore, EM analysis should be carried out to perform design optimizations in order to minimize unwanted effects of high frequencies. The solver developed in this work is an appropriate solution to address the needs of EM analysis in general and power electronics in particular. The conducted research consists of performance acceleration and implementation of the solver, and verification of the simulation results by means of measurements. This work was done in two major phases.In the first phase, the solver was accelerated to optimize its performance when quasi-static (R,Lp,C)PEEC as well as full-wave (R,Lp,C,tau)PEEC simulations were carried out. The main optimizations were based on exploiting parallelism and high performance computing to solve very large problems and non-uniform mesh, which was helpful in simulating skin- and proximity effects while keeping the problem size to a minimum. The presented results and comparisons with the measurements confirmed that non-uniform mesh helped in accurately simulating large bus bar models and correctly predicting system resonances when the size of the problem was minimized. On-the-fly calculation was also developed to reduce memory usage, while increasing solution time.The second phase consists of methods to increase the performance of the solver while including some levels of approximations. In this phase sparsification techniques were used to convert a dense PEEC system into a sparse system. The sparsification was done by calculating the reluctance matrix, which can be sparsified by maintaining the accuracy at the desired level, because of the locality and the shielding effect of the reluctance matrix. Efficient algorithms were developed to perform sparse matrix-matrix multiplication and assemble the sparse coefficient matrix in a row-by-row manner to reduce the peak memory usage. The sparse system was then solved using both sparse direct and iterative solvers with proper preconditioning. The acquired results from the sparse direct solution confirmed that the memory consumption and solution time were reduced by orders of magnitude and by a factor 3 to 5. Moreover, the Schur complement was used together with the iterative approach, making it possible to solve large problems within a few iterations by preconditioning the system, and using less memory and lower computational complexity. Bus bars used in two types of power frequency converters manufactured by ABB were modelled and analysed with the developed PEEC-based solver in this research, and the simulations and measurements agreed very well. Results of simulations also led to improvement in the physical design of the bars, which reduced the inductance of the layout.With the accelerated solver, it is now possible to solve very large and complex problems on conventional computer systems, which was not possible before. This provides new possibilities to study real-world problems which are typically large in size and have complex structures. / Godkänd; 2012; 20121114 (dan); DISPUTATION Ämne: Industriell elektronik/Industrial Electronics Opponent: PhD Bruce Archambeault, IBM, Research Triangle Park, North Carolina, USA. Opponenten utför sitt uppdrag via distansöverbryggande teknik Ordförande: Docent Jonas Ekman, Institutionen för system- och rymdteknik, Luleå tekniska universitet Tid: Torsdag den 17 januari 2013, kl 13.30 Plats: A109, Luleå tekniska universitet

The fields of navigation and motion inference have rapidly been transformed by advances in computing, connectivity, and sensor design. As a result, unprecedented amounts of data are today being collected by cheap and small navigation sensors residing in our surroundings. Often, these sensors will be embedded into personal mobile devices such as smartphones and tablets. To transform the collected data into valuable information, one must typically formulate and solve a statistical inference problem. This thesis is concerned with inference problems that arise when trying to use smartphone sensors to extract information on driving behavior and traffic conditions. One of the fundamental differences between smartphone-based driver behavior profiling and traditional analysis based on vehicle-fixed sensors is that the former is based on measurements from sensors that are mobile with respect to the vehicle. Thus, the utility of data from smartphone-embedded sensors is diminished by not knowing the relative orientation and position of the smartphone and the vehicle. The problem of estimating the relative smartphone-to-vehicle orientation is solved by extending the state-space model of a global navigation satellite system-aided inertial navigation system. Specifically, the state vector is augmented to include the relative orientation, and the measurement vector is augmented with pseudo observations describing well-known characteristics of car dynamics. To estimate the relative positions of multiple smartphones, we exploit the kinematic relation between the accelerometer measurements from different smartphones. The characteristics of the estimation problem are examined using the Cramér-Rao bound, and the positioning method is evaluated in a field study using concurrent measurements from seven smartphones. The characteristics of smartphone data vary with the smartphone's placement in the vehicle. To investigate this, a large set of vehicle trip segments are clustered based on measurements from smartphone-embedded sensors and vehicle-fixed accelerometers. The clusters are interpreted as representing the smartphone being rigidly mounted on a cradle, placed on the passenger seat, held by hand, etc. Finally, the problem of fusing speed measurements from the on-board diagnostics system and a global navigation satellite system receiver is considered. Estimators of the vehicle’s speed and the scale factor of the wheel speed sensors are derived under the assumptions of synchronous and asynchronous samples. / <p>QC 20171123</p>

In the district heating industry, heat meters, consisting among other things of a flow meter, are used for billing purpose. The district heating industry desires accurate and low cost flow measurements. There are mainly two reasons. An under estimation of the flow rate leads to a loss of income for the district heating industry. Further, the total cost for measuring, including the cost for the heat meter, the reading and the maintenance, represents a relatively large part of the total energy cost. Therefore a project concerning measurement quality assurance in district heating systems is in progress at Luleå University of Technology. As a part of this project the possibility of self diagnostic techniques for flow meters is investigated. It is well known that installation effects greatly impair the flow measurement involved in heat metering. Thus this thesis focus on self diagnostics of different installation effects. The basic assumption is that the flow meter noise level is correlated to turbulence intensity. Since the turbulence intensity is effected by installation effects, the noise level can be used to detect conditions for which the flow meter shows erroneous results. In district heating applications the use of ultrasonic flow meters are becoming more and more frequent. The self diagnostic approach has therefore been investigated for a small size prototype ultrasonic flow meter. Single and double elbow pipe bends and pipe diameter reductions mounted in front of the meter and pulsating flow give rise to small but reproducible errors. The magnitude of the maximum errors were in the range of 2 to 4% of flow rate. At low flow rates with pulsating flow the errors were larger. Also small commercial ultrasonic flow meters were investigated. These commercial meters are commonly used in heat meters in small district heating subscriber stations. The results demonstrate that both temperature changes and installation effects introduce errors in the flow measurements. By studying the noise level of the signal from the prototype ultrasonic flow meter it is clear that all installation effects tested caused a clear increase in the flow signal noise level. It is clear that no tested disturbance causing measurement errors, larger than 1% of the flow rate, will pass undetected. Neither will normal conditions with a varying flow rate or single measurement outliers cause false alarms. It is anticipated that this increase in the future can be detected on-line by the flow meter itself giving it a self diagnostic capability. / <p>Godkänd; 2001; 20061115 (haneit)</p>

Flow metering plays a major role in modern life. In the process industry, flow metering is critical in industries ranging from food processing to cosmetics. It is also essential in custody transfer or billing, as flow meters are present in gas pumps and district heating substations. In the district heating industry, the ultrasonic flow meter has become the desired meter in many of its applications because it has a low cost while being accurate. This accuracy is however sensitive to installation effects and other sources of errors. This thesis stems from research that addresses the recognition of these installation effects, informs when they are unacceptable and considers reducing the measurement errors. To present these concepts, the thesis details the estimation of the mean flow velocity, the calibration of the meter and the measurement noise properties. Once installed, any kind of meter provides larger errors than in the facility where it has been calibrated and compensated. It is particularly true for ultrasonic flow meters as they are very sensitive to installation effects. Installation effects can either be static or dynamic. Special attention is paid to errors generated by temperature and velocity profile variations. Velocity profile variations can be due to pipe bends or flow pulsations. Such disturbances often induce a bias error and change the properties of the measurement noise. It is therefore with help of the change in noise that velocity profile disturbances can be detected. The detection of such abnormal behaviour of the measurement process constitutes a diagnosis. A diagnosis of the sensitivity of the meter to installations effects would allow for compensations for the errors. Signal analysis allows detection of specific noise properties, characteristic of installation effects. An example of self-diagnosis showing the detection of real pulsations in a flow is described in details. The detection of the flow pulsations and the estimation of their frequency allow to reduce the error of estimation on the flow rate. This technique is confirmed by the simulations of a pulsating flow. To empower one with the decision whether a flowmeter performance is normal or abnormal, a study of the relative error as a function of flow rate and temperature has been conducted. / <p>Godkänd; 2004; 20080708 (evan)</p>

Today a number of different optical techniques capable of measuring range, velocity or both exist. With recent advancements in laser diode manufacturing, small tunable sources have become available. By modulating current supplied to the laser the optical output frequency can be modulated. If the outgoing modulated light is divided into two parts, a transmitted and a local oscillator part, and a photodiode is used as detector, the frequency difference between the two parts can be obtained directly from the photodiode current. This frequency difference is often referred to as the beat frequency. If triangular frequency modulation is used, both range and radial velocity can be determined from the measured beat frequency. The common name for this technique, which was first implemented using regular radar, is frequency modulated continuous wave (FMCW). The thesis consists of an introduction and five papers. Paper one is a theoretical investigation where contributions from different noise sources are discussed. We have investigated how the signal to noise ratio for the photodiode is affected by how the optical power is divided between the transmitted part and the local oscillator part. Paper number two introduces a new modulation scheme that avoids ambiguity problems resulting from a Doppler shift larger than the frequency shift associated with the range. As a result of this new modulation scheme other benefits are also gained. The modulation scheme was tested and verified in our lab system built with a tunable laser diode and a fiber optic coupler. Paper number three presents a single stage OP-amp solution suited for an FMCW system. Our circuit combines a high gain in the desired frequency region with minimal gain at dc, without using any inductors. The risk of saturation or clipping due to the local oscillator can thereby greatly be reduced. Inserting a high pass filter between the photodiode and the first amplifier stage, to remove the dc level, is often not practical when using a regular current to voltage converter. A cascade of two stages, with a high pass filter between the two, is therefore commonly used. Our solution has similar performance as the cascade solution, but since it uses only one OP-amp, it is less sensitive to external disturbances. Paper number four and five deal with a common problem in an FMCW systems where the optical frequency is used as the carrier wave, and the modulation is obtained by modulating a current to the laser. For optimum performance, the frequency sweep should be as linear as possible, but due to thermal effects, a linear current ramping seldom results in a linear frequency ramping. At lower modulation frequencies, below 1 MHz, the temperature behaviour of the laser has a large influence on the frequency behaviour. To model the frequency behaviour we hence started by investigating the thermal behaviour. This work is presented in paper four. The goal is to obtain a model for the frequency behaviour with respect to changes in the laser drive current. In paper five, this model has been tweaked a bit and is used to obtain modulation currents that gives a linear frequency ramping. / <p>Godkänd; 2004; 20061025 (haneit)</p>