Wireless Authentication and Authorization, case Wireless Access Control System

Lyhyen kantaman radiotekniikoiden hyödyntäminen mahdollistaa uudenlaisten paikallisten palveluiden käytön ja vanhojen palveluiden kehittämisen. Kulunvalvonta on päivittäisenä palveluna valittu työn esimerkkisovellukseksi. Useita tunnistus- ja valtuutustapoja tutkitaan, ja julkisen avaimen infrastruktuuri on esitellään tarkemmin. Langattomat tekniikat Bluetooth, Zigbee, RFID ja IrDA esitellän yleisellä tasolla langattomat tekniikat –luvussa. Bluetooth-tekniikan rakennetta, mukaan lukien sen tietoturva-arkkitehtuuria, tutkitaan tarkemmin. Bluetooth-tekniikkaa käytetään työssä suunnitellun langattoman kulunvalvontajärjestelmän tietojen siirtoon. Kannettava päätelaite toimii käyttäjän henkilökohtaisena luotettuna laitteena, jota voi käyttää avaimena. Käyttäjän tunnistaminen ja valtuuttaminen perustuu julkisen avaimen infrastruktuuriin. Ylläpidon allekirjoittamat varmenteet sisältävät käyttäjän julkisen avaimen lisäksi tietoa hänestä ja hänen oikeuksistaan. Käyttäjän tunnistaminen kulunvalvontapisteissä tehdään julkisen ja salaisen avaimen käyttöön perustuvalla haaste-vastaus-menetelmällä. Lyhyesti, järjestelmässä käytetään Bluetooth-päätelaitteita langattomina avaimina.

Modernization of protection and control system of HV/MV substation in Russia

This work describes different possibilities of protection and control system improvement of primary distribution substation. The status of condition and main problems of power networks from reliability point of view in Russia are described. This work studies technologies used today in Russia for protection of distribution networks with their disadvantages. Majority of medium voltage networks (6-35 kV) has isolated network point. There is still no any protection available on the market which allows to estimate distance to fault in case of earth fault. The thesis analyses methods of earth fault distance calculation. On the basis of computer simulation the influence of various factors on calculation accuracy is studied. The practical implementation of the method presupposes usage of digital relay. Application of digital relay is accompanied by numerous opportunities which are described in this work. Also advantages of system implemented on the basis of IEC 61850 standard are examined. Finally, suitability of modern digital relays from GOST standard point of view is analyzed.

RTOS Framework for Real-Time Control System

This thesis is done as a complementary part for the active magnet bearing (AMB) control software development project in Lappeenranta University of Technology. The main focus of the thesis is to examine an idea of a real-time operating system (RTOS) framework that operates in a dedicated digital signal processor (DSP) environment. General use real-time operating systems do not necessarily provide sufficient platform for periodic control algorithm utilisation. In addition, application program interfaces found in real-time operating systems are commonly non-existent or provided as chip-support libraries, thus hindering platform independent software development. Hence, two divergent real-time operating systems and additional periodic extension software with the framework design are examined to find solutions for the research problems. The research is discharged by; tracing the selected real-time operating system, formulating requirements for the system, and designing the real-time operating system framework (OSFW). The OSFW is formed by programming the framework and conjoining the outcome with the RTOS and the periodic extension. The system is tested and functionality of the software is evaluated in theoretical context of the Rate Monotonic Scheduling (RMS) theory. The performance of the OSFW and substance of the approach are discussed in contrast to the research theme. The findings of the thesis demonstrates that the forged real-time operating system framework is a viable groundwork solution for periodic control applications.

Researching Manufacturing Planning and Control system and Master Scheduling in a manufacturing firm.

The objective of this thesis is to research Manufacturing Planning and Control (MPC) system and Master Scheduling (MS) in a manufacturing firm. The study is conducted at Ensto Finland Corporation, which operates on a field of electrical systems and supplies. The paper consists of theoretical and empirical parts. The empirical part is based on weekly operating at Ensto and includes inter-firm material analysis, learning and meetings. Master Scheduling is an important module of an MPC system, since it is beneficial on transforming strategic production plans based on demand forecasting into operational schedules. Furthermore, capacity planning tools can remarkably contribute to production planning: by Rough-Cut Capacity Planning (RCCP) tool, a MS plan can be critically analyzed in terms of available key resources in real manufacturing environment. Currently, there are remarkable inefficiencies when it comes to Ensto’s practices: the system is not able to take into consideration seasonal demand and react on market changes on time; This can cause significant lost sales. However, these inefficiencies could be eliminated through the appropriate utilization of MS and RCCP tools. To utilize MS and RCCP tools in Ensto’s production environment, further testing in real production environment is required. Moreover, data accuracy, appropriate commitment to adapting and learning the new tools, and continuous developing of functions closely related to MS, such as sales forecasting, need to be ensured.

Development of a measuring-control system for energy monitoring in low power

In this thesis a control system for an intelligent low voltage energy grid is presented, focusing on the control system created by using a multi-agent approach which makes it versatile and easy to expand according to the future needs. The control system is capable of forecasting the future energy consumption and decisions making on its own without human interaction when countering problems. The control system is a part of the St. Petersburg State Polytechnic University’s smart grid project that aims to create a smart grid for the university’s own use. The concept of the smart grid is interesting also for the consumers as it brings new possibilities to control own energy consumption and to save money. Smart grids makes it possible to monitor the energy consumption in real-time and to change own habits to save money. The intelligent grid also brings possibilities to integrate the renewable energy sources to the global or the local energy production much better than the current systems. Consumers can also sell their extra power to the global grid if they want.

Design of the sensorless pressure control system for a centrifugal pump

This thesis investigates the pressure-based control of a variable-speed-driven pump system in the case of existing output pressure measurement and in the case of sensorless system, where the actual output pressure value is calculated with the steady state estimator.

Development of a Control System for a Tele Operated Mobile Robot

Mobile robots are capable of performing spatial displacement motions in different environments. This motions can be calculated based on sensorial data (autonomous robot) or given by an operator (tele operated robot). This thesis is focused on the latter providing the control architecture which bridges the tele operator and the robot’s locomotion system and end effectors. Such a task might prove overwhelming in cases where the robot comprises a wide variety of sensors and actuators hence a relatively new option was selected: Robot Operating System (ROS). The control system of a new robot will be sketched and tested in a simulation model using ROS together with Gazebo in order to determine the viability of such a system. The simulated model will be based on the projected shape and main features of the real machine. A stability analysis will be performed first theoretically and afterwards using the developed model. This thesis concluded that both the physical properties and the control architecture are feasible and stable settling up the ground for further work with the same robot.

Kalman Filtering in Online Paper Quality Assessment

Controlling the quality variables (such as basis weight, moisture etc.) is a vital part of making top quality paper or board. In this thesis, an advanced data assimilation tool is applied to the quality control system (QCS) of a paper or board machine. The functionality of the QCS is based on quality observations that are measured with a traversing scanner making a zigzag path. The basic idea is the following: The measured quality variable has to be separated into its machine direction (MD) and cross direction (CD) variations due to the fact that the QCS works separately in MD and CD. Traditionally this is done simply by assuming one scan of the zigzag path to be the CD profile and its mean value to be one point of the MD trend. In this thesis, a more advanced method is introduced. The fundamental idea is to use the signals’ frequency components to represent the variation in both CD and MD. To be able to get to the frequency domain, the Fourier transform is utilized. The frequency domain, that is, the Fourier components are then used as a state vector in a Kalman filter. The Kalman filter is a widely used data assimilation tool to combine noisy observations with a model. The observations here refer to the quality measurements and the model to the Fourier frequency components. By implementing the two dimensional Fourier transform into the Kalman filter, we get an advanced tool for the separation of CD and MD components in total variation or, to be more general, for data assimilation. A piece of a paper roll is analyzed and this tool is applied to model the dataset. As a result, it is clear that the Kalman filter algorithm is able to reconstruct the main features of the dataset from a zigzag path. Although the results are made with a very short sample of paper roll, it seems that this method has great potential to be used later on as a part of the quality control system.

Phase voltage control and filtering in a converter-fed single-phase customer-end system of the LVDC distribution network

In recent years, the network vulnerability to natural hazards has been noticed. Moreover, operating on the limits of the network transmission capabilities have resulted in major outages during the past decade. One of the reasons for operating on these limits is that the network has become outdated. Therefore, new technical solutions are studied that could provide more reliable and more energy efficient power distributionand also a better profitability for the network owner. It is the development and price of power electronics that have made the DC distribution an attractive alternative again. In this doctoral thesis, one type of a low-voltage DC distribution system is investigated. Morespecifically, it is studied which current technological solutions, used at the customer-end, could provide better power quality for the customer when compared with the current system. To study the effect of a DC network on the customer-end power quality, a bipolar DC network model is derived. The model can also be used to identify the supply parameters when the V/kW ratio is approximately known. Although the model provides knowledge of the average behavior, it is shown that the instantaneous DC voltage ripple should be limited. The guidelines to choose an appropriate capacitance value for the capacitor located at the input DC terminals of the customer-end are given. Also the structure of the customer-end is considered. A comparison between the most common solutions is made based on their cost, energy efficiency, and reliability. In the comparison, special attention is paid to the passive filtering solutions since the filter is considered a crucial element when the lifetime expenses are determined. It is found out that the filter topology most commonly used today, namely the LC filter, does not provide economical advantage over the hybrid filter structure. Finally, some of the typical control system solutions are introduced and their shortcomings are presented. As a solution to the customer-end voltage regulation problem, an observer-based control scheme is proposed. It is shown how different control system structures affect the performance. The performance meeting the requirements is achieved by using only one output measurement, when operating in a rigid network. Similar performance can be achieved in a weak grid by DC voltage measurement. An additional improvement can be achieved when an adaptive gain scheduling-based control is introduced. As a conclusion, the final power quality is determined by a sum of various factors, and the thesis provides the guidelines for designing the system that improves the power quality experienced by the customer.

Control of multi-actuator system by an electrically driven hydraulic pump-motor

The awareness and concern of our environment together with legislation have set more and more tightening demands for energy efficiency of non-road mobile machinery (NRMM). Integrated electro-hydraulic energy converter (IEHEC) has been developed in Lappeenranta University of Technology (LUT). The elimination of resistance flow, and the recuperation of energy makes it very efficient alternative. The difficulties of IEHEC machine to step to the market has been the requirement of one IEHEC machine per one actuator. The idea is to switch IEHEC between two actuators of log crane using fast on/off valves. The control system architecture is introduced. The system has been simulated in co-simulation using two different software. The simulated responses of pump-controlled system is compared to the responses of the conventional valve-controlled system.

Implementing theLean Manufacturing System

Tuottavuuden ja tehokkuuden parantaminen on keskeisimpiä menestystekijöitä glo-baaleilla markkinoilla. Yksi kehittämisen toimintamalli on lean manufacturing -ajattelutapa, joka perustuu imuohjaukseen. Sen lähtökohtana on asiakasarvo ja keskit-tyminen arvoa lisäävien toimintojen maksimointiin. Tutkimuksen tavoitteena oli parantaa Strömfors Electric Oy:n materiaalivirtauksia yhdellä tuotantolinjalla. Projektin oli tarkoitus olla pilotti lean-implementointiin koko tehtaalla. Projektissa otettiin käyttöön kanban-imuohjausjärjestelmä, jota varten teh-tiin analyysejä ja laskelmia arvovirtoihin, varastoihin ja ohjaukseen. Lean-ajattelutapaan ja -työkaluihin perustuvaa kirjallisuutta käytettiin pohjatietona pilotti-projektissa sekätulevien kehitysprojektien suunnittelussa. Pilottiprojektin tuloksena materiaalinohjaus tehostui ja keskeneräisen tuotannon va-rasto tasoittui käyttötarpeen mukaiseksi. Työntekijät ja työnjohtajat tutustuivat leanin perusteisiin osallistuessaan pilottiprojektiin. Pidemmän aikavälin suunnitelmissa ontoimitusvarmuuden ja laadun parantuminen ensin pilottiprojektia koskevalla linjalla ja myöhemmin koko tehtaalla imuohjauksen kokonaisvaltaisen käyttöönoton myötä.

Field Sales Management Control: Towards a Multi-Level Theory

The purpose of this dissertation is to increase the understanding and knowledge of field sales management control systems (i.e. sales managers monitoring, directing, evaluating and rewarding activities) and their potential consequences on salespeople. This topic is important because research conducted in the past has indicated that the choice of control system type can on the other hand have desirable consequences, such as high levels of motivation and performance, and on the other hand leadto harmful unintended consequences, such as opportunistic or unethical behaviors. Despite the fact that marketing and sales management control systems have been under rigorous research for over two decades, it still is at a very early stage of development, and several inconsistencies can be found in the research results. This dissertation argues that these inconsistencies are mainly derived from misspecification of the level of analysis in the past research. These different levels of analysis (i.e. strategic, tactical, and operational levels) involve very different decision-making situations regarding the control and motivation of sales force, which should be taken into consideration when conceptualizing the control. Moreover, the study of salesperson consequences of a field sales management control system is actually a cross-level phenomenon, which means that at least two levels of analysis are simultaneously involved. The results of this dissertation confirm the need to re-conceptualize the field sales management control system concept. It provides empirical evidence for the assertion that control should be conceptualized with more details atthe tactical/operational level of analysis than at the strategic levelof analysis. Moreover, the results show that some controls are more efficiently communicated to field salespeople than others. It is proposed that this difference is due to different purposes of control; some controls aredesigned for influencing salespersons' behavior (aim at motivating) whereas some controls are designed to aid decision-making (aim at providing information). According to the empirical results of this dissertation, the both types of controls have an impact to the sales force, but this impactis not as strong as expected. The results obtained in this dissertation shed some light to the nature of field sales management control systems, and their consequences on salespeopl

Converter-flux-based current control of voltage source PWM rectifiers - analysis and implementation

Pulsewidth-modulated (PWM) rectifier technology is increasingly used in industrial applications like variable-speed motor drives, since it offers several desired features such as sinusoidal input currents, controllable power factor, bidirectional power flow and high quality DC output voltage. To achieve these features,however, an effective control system with fast and accurate current and DC voltage responses is required. From various control strategies proposed to meet these control objectives, in most cases the commonly known principle of the synchronous-frame current vector control along with some space-vector PWM scheme have been applied. Recently, however, new control approaches analogous to the well-established direct torque control (DTC) method for electrical machines have also emerged to implement a high-performance PWM rectifier. In this thesis the concepts of classical synchronous-frame current control and DTC-based PWM rectifier control are combined and a new converter-flux-based current control (CFCC) scheme is introduced. To achieve sufficient dynamic performance and to ensure a stable operation, the proposed control system is thoroughly analysed and simple rules for the controller design are suggested. Special attention is paid to the estimationof the converter flux, which is the key element of converter-flux-based control. Discrete-time implementation is also discussed. Line-voltage-sensorless reactive reactive power control methods for the L- and LCL-type line filters are presented. For the L-filter an open-loop control law for the d-axis current referenceis proposed. In the case of the LCL-filter the combined open-loop control and feedback control is proposed. The influence of the erroneous filter parameter estimates on the accuracy of the developed control schemes is also discussed. A newzero vector selection rule for suppressing the zero-sequence current in parallel-connected PWM rectifiers is proposed. With this method a truly standalone and independent control of the converter units is allowed and traditional transformer isolation and synchronised-control-based solutions are avoided. The implementation requires only one additional current sensor. The proposed schemes are evaluated by the simulations and laboratory experiments. A satisfactory performance and good agreement between the theory and practice are demonstrated.

Production Control Principles in Printed Wiring Board Fabrication

Työn tavoitteena oli kuvata piirilevyvalmistaja Aspocomp Oy:n Espoon tehtaan tämän hetkinen tuotannonohjausperiaate ja tunnistaa siinä esiintyvät puutteet sekä kehittää vaihtoehtoinen tuotannonohjausperiaate piirilevyvalmistukseen. Vaihtoehtoisen ohjausperiaatteen lähtökohtana oli tuotannonohjauksen sopeuttaminen vaativaan ja jatkuvasti muuttuvaan liiketoimintaympäristöön. Työn teoreettinen osa keskittyi tuotannonohjauksen eri lähestymistapoihin. Kirjallisuuskatsauksessa esitetään eri tuotannonohjausperiaatteiden keskeiset sisällöt, jotka muodostavat rungon toimivalle tuotannonohjauskäytännölle. Työn kokeellinen osa keskittyi Espoon piirilevytehtaan tuotannonohjausperiaatteen selvittämiseen. Espoon piirilevytehtaan nykyisessä tuotannonohjausperiaatteessa havaittujen ongelmakohtien ja liiketoimintaympäristön vaatimusten perusteella kehitettiin vaihtoehtoinen tuotannonohjaustapa. Vaihtoehtoisen tuotannonohjaustavan päämääränä oli läpimenoajan lyhentäminen sekä tuotannon parempi hallittavuus. Vaihtoehtoinen toimintamalli tavoitteiden saavuttamiseksi perustuu pullonkaulateoriaan, jossa keskeisin muutos nykyiseen toimintamalliin oli puolivalmisteiden varastointi toimitusajan lyhentämiseksi sekä tuotantovolyymin heilahdusten vaikutusten vähentämiseksi. Työn kokeellisessa osassa ilmeni, että kysynnän muutokset ja kapasiteetin suunnittelun puute aiheuttivat ongelmia piirilevytehtaan tuotannonohjauksessa.