The Laser Interferometer Space Antenna (LISA) will be the first gravitational wave detector in space. The European Space Agency has selected LISA as a large mission scheduled to launch in the mid-2030s. The sensitivity of LISA to gravitational waves is limited at low frequencies by force disturbances acting on the otherwise free-falling test masses. Among the stray forces relevant to the LISA noise budget, we find the ones that arise from the electrostatic interaction between the test masses and the surrounding capacitive sensor. Most of such electrostatic forces scale with the electric charge deposited on the test masses. This problem is aggravated by the fact that isolated objects in space, such as the floating LISA test masses, accumulate electric charge due to the constant bombardment of cosmic rays and solar energetic particles. We, therefore, understand that if the test masses were not discharged, the electrostatic disturbances could spoil the performance of the whole mission at low frequency. The precursor LISA Pathfinder (LPF) mission proved that the test mass charge could be successfully managed with a contactless system based on photoelectric charge transfer. The light sources required for photoemission in LISA Pathfinder were mercury-vapor lamps emitting photons in the UV range. In this thesis, we will present our on-ground testing campaign of a prototype Charge Management System for LISA, which relies on UV-LEDs as light sources. LEDs, compared to mercury-vapor lamps, can emit short pulses of UV light (~10 ns), which can be synchronized with the time-varying electrostatic fields around the test mass. For this reason, we studied new discharge strategies made possible by adopting UV-LEDs characterized by pulsed illumination synced with the capacitive sensing injection bias. Our measurements indicate that UV-LEDs offer significant advantages regarding the flexibility and robustness of the Charge Management System. Moreover, the new illumination patterns offered by UV-LEDs allow fine-tuning the TM equilibrium potential without introducing local DC fields, easing the implementation of the continuous discharge mode to manage the TM potential. Finally, we investigated the charge noise introduced by the continuous discharge mode and verified that it could be kept within the LISA requirements. We will present hereafter the outline of the thesis. In the first chapter, we present a mandatory introduction to gravitational waves and the LISA mission. In the second chapter, we present the instrument used for our experimental campaign, namely the four-test-masses torsion pendulum at the University of Trento. We also present the electrostatic model and the measurement techniques used to evaluate the electric charge on the pendulum test mass. In the third chapter, we introduce the concept of apparent yield, which is a figure of merit of the charge management system performance. We also present our experimental measurement, which encompasses tests on several UV-LEDs in different illumination patterns. In the fourth chapter, we derive a simple photoemission model, which is useful for interpreting the apparent yield data acquired. We will also use the model to fit the experimental data and extract estimates of the microscopic parameters that affect the photoemission from metallic surfaces, e.g. work function or quantum yield. In the fifth chapter, we present a model and our torsion pendulum measurements for the charge noise induced on the test masses when continuously illuminated with UV light. Such noise arises from the discrete and intrinsically stochastic nature of photoelectric charge transfer. Finally, in the last chapter, we will wrap up by presenting the problems encountered and the "lessons learned" during the years-long experimental endeavor.

Thermal management has become a major concern in the design of current and future more and all electric aircraft (M/AEA). With ever increasing numbers of on-board heat sources, higher heat loads, limited and even decreasing numbers of heat sinks, integration of advanced intelligence, surveillance and reconnaissance (ISR) and directed energy weapons, requirements for survivability, the use of composite materials, etc., existing thermal management systems and their components have been pushed to the limit. To address this issue, more efficient methods of thermal management must be implemented to ensure that these new M/AEA aircraft do not overheat and prematurely abort their missions. Crucial to this effort is the need to consider advanced heat exchanger concepts, comparing their designs and performance with those of the conventional compact exchangers currently used on-board aircraft thermal management systems. As a step in this direction, the work presented in this thesis identifies two promising advanced heat exchanger concepts, namely, microchannel and phase change heat exchangers. Detailed conceptual design and performance models for these as well as for a conventional plate-fin compact heat exchanger are developed and their design and performance optimized relative to the criterion of minimum dry weight. Results for these optimizations are presented, comparisons made, conclusions drawn, and recommendations made for future research. These results and comparisons show potential performance benefits for aircraft thermal management incorporating microchannel and phase change heat exchangers. / Master of Science

The proposed cell monitoring unit for sensing voltage, current, and temperature in a 12-cell 18650 lithium-ion battery module aims to be low-power, serving as the core of an energy-efficient battery management system and facilitating battery management functions with cell data. Notable features include a switchable voltage divider, a single op-amp differential amplifier and level shifter, and a high-precision composite amplifier. The proposed circuit is implemented on a printed circuit board. Measurement results show that the highest power dissipation under continuous operation is from the current sensing circuit at 6.03 mW under a 4 A string current, followed by the voltage sensing at 2.52 mW for the top cell and the temperature sensing at 34.9 μW. The measured power figures include the power dissipation from the battery cells in addition to the cell monitoring unit. The maximum output error is 68 mV for cell voltages up to 44.4 V, 36 mA for current up to 4 A, and 0.37 ◦C for temperature up to 73 ◦C. / M.S. / Battery management systems are required in modern rechargeable battery-operated devices to help ensure that the batteries operate within the manufacturer-specified operating range. Otherwise, damage to the batteries or to the device may occur. Battery modules are comprised of smaller energy cells to achieve the specified energy capacity and power output. At the core of a battery management system is a battery cell monitoring unit that interfaces the management system with the battery module by providing data about each of the battery cells, including voltage, current, and temperature. To help minimize the power dissipation of battery-powered devices and prolong the battery life, the power consumed by the battery management system should be small. This project aims to detail the design and results of a low-power cell monitoring unit as the core component of energy-efficient battery management systems. The proposed circuit is designed for a 12-cell lithium-ion battery module and implemented on a printed circuit board. The maximum measured power dissipation under continuous operation is 6.03 mW for the current sensing circuit, followed by the voltage sensing circuit at 2.52 mW and the temperature sensing circuit at 34.9 μW.

Digital libraries are fast expanding into the role of independent educational entities that aspire not only to complementing traditional classroom teaching, but also allow open electronic learning for distance and continued education. These multifaceted roles can be realized only if the course content and the related content management system are versatile enough to be captured into any individual's learning needs. Many studies have defined a concept of "learning object" to address the issues and needs. But in attempting to solve the problem, the definitions have emphasized some aspects of the digital library while leaving the other issues to be solved later. Thus, the whole system dynamics is either weak or too cumbersome to navigate. As a part of this masters work, firstly the current model of pedagogical endowment was investigated. In order to accommodate the digital nature of education, a new modern profile of learning is proposed that allows modular yet efficient transfer of knowledge from the teacher to the pupil. The thesis then proposes a comprehensive learning object (LO) model, along with the associated system model, that will allow complete and flexible integration of content into the modern digital library profile. The process will be user-centric (both for knowledge developers and learners) as well as metadata-centric. It is scalable and interoperable with legacy and existing content databases and display systems. This thesis covers how the LO model is integrated into the core of the library's content development, discovery, and delivery process. The results of the experiment in terms of ease-of-use, flow-control, and feasibility of the model are documented. A beta-version of these concepts has been successfully tested with volunteers and implemented as a part of the Digital Library Network for Engineering and Technology (DLNET) project. / Master of Science

BakgrundMånga gymnasieskolor i Sverige har infört eller är på väg att införa en lärplattform. Det finns dock sällan några riktlinjer till vad man ska använda lärplattformen. Läraren får friheten att använda plattformen till de ändamål som passar denna. Hur läraren ser på sitt uppdrag blir alltså väsentligt för hur lärplattformen används. Vi har därför valt att undersöka hur lärare ser på de nya möjligheter som lärplattformen ger.SyfteUndersökningen har haft som syfte att åskådliggöra hur lärarens yrkesidentitet utmanas av lärplattformen.• Hur ställer sig lärarna till lärplattformens obundenhet i tid och rum?• Hur ställer sig lärarna till att de inte längre är dominerande kunskapsförmedlare iskolan?MetodVi har genomfört kvalitativa intervjuer på två gymnasieskolor i Västra Sverige. Totalt har vi pratat med sex lärare i ca 45 minuter vardera. Det insamlade resultatet har vi analyserat utifrån Gunnar Bergs teori om skolans uppdrag och skolors uppgifter.ResultatVi har funnit att lärarna ser att vissa av deras yrkesuppdrag skulle påverkas av ett ökat användande av en lärplattform. Dessa tre uppdrag benämner vi som det ämnesförmedlande uppdraget, det socialiserande uppdraget och det kvalitetssäkrande och bedömande uppdraget.Vidare har vi funnit att lärarna inte vill använda lärplattformen för att ändra deras verksamhet utan enbart för att stödja de uppgifter de redan har.

<p>Idag har de flesta företag och organisationer någon form för intranät-lösning. Dessa lösningar kan vara både mer och mindre sofistikerade, men har oftast det samma syfte; att distribuera organisationens information till dess medlemmar.</p><p>Denna uppsats ägnar sig åt intranät och fördjupar sig i ett begrepp som vuxit starkt de senaste åren, nämligen Content Management System (CMS). Jag fokuserar särskilt på val av Open Source CMS, för implementation i mindre organisationers intranät.</p><p>Uppsatsen är ett resultat av omfattande litteraturstudier inom sitt område och bygger främst på vetenskapliga artiklar av ledande experter. Ytterligare en källa är resultatet av en enkätundersökning, som också redovisas i uppsatsen. Denna enkät hade som ändamål, att kartlägga användares attityder till deras CMS-intranät.</p><p>Uppsatsens kanske viktigaste resultat är en redogörelse för hur ett moduliserad CMS-intranät skulle kunna utformas, baserad på bl.a. Knowledge Management-teori, där tyngdpunkten ligger på de personliga referensernas betydelse för en människas tolkning av sin omgivning, och logisk kategorisering av information.</p> / <p>Today, most companies and organizations have some kind of intranet solution. These system solutions vary and tend to be either more or less sophisticated, but the overall purpose remains the same; distributing the organizations information to its members.</p><p>This essay is about intranet-development, and mainly devoted to explore a concept which has grown rapidly in recent years; Content Management System (CMS). I’m particular focusing on how to choose a suitable Open Source CMS, for implementation in a small organizations intranet.</p><p>The essay is the result of vast literature studies, mainly based on scientific articles from leading experts within their field. In addition I have also carried out a survey in a company intranet, in order to investigate the users’ attitude towards their CMS-intranet.</p><p>One of the most important results of the essay is my model of a modularized CMS-intranet, partially based on Knowledge Management-theory and the importance of appropriate references in order to interpret our surroundings, and logical categorization of information.</p>

Många lärosäten använder idag fler än en lärplattform, ibland inom en och samma institution, program eller kurs. Uppsatsens syfte var därför att ta fram riktlinjer för vad som bör beaktas vid val av lärplattform för att fylla organisationens behov och passa dess förutsättningar. Undersökningen genomfördes med en kvalitativ datainsamlingsmetod där vi genom intervjuer med fem lärare vid Linnéuniversitetet samlade in deras krav. Resultatet blev en checklista som listar lärarnas krav och genom att kritiskt granskat litteratur kan vi rekommendera organisationer vad de bör överväga inför implementationen av en lärplattform. / Today, many institutions use more than one learning management system, sometimes within the same department, education program or course. The purpose of the essay was therefore to create guidelines for what should be considered when selecting a learning management system to meet the organizations needs and best suit their circumstances. The survey was conducted by a qualitative data collection method in which we collected the requirements of five teachers at Linnaeus University through interviews. The result was a checklist that lists teachers’ demands. By critical reviews of the literature we can recommend to organizations what they should consider before implementation of a learning management system.

After the ISO9000 series of quality management standards was released by the International Organization of Standard, certificate of ISO9001¡G1994 was deemed by enterprises as a guarantee for performance improvement. Ironically, not until recently is the implementation of ISO9001: 2000 substantially depreciated and suspected as an obstacle to efficient operation. Since the certificate of ISO9001 still represents the passport to be a candidate in international trade, enterprises bear to implement ISO9001 even under the circumstance that they do not understand the value of ISO9001. This not only violates the basic requirements of ISO9001: 2000 but also leads to employee¡¦s careless attitude about the practice. The prevalence of different evaluation tools such as Key Performance Index (KPI), Management By Objectives (MBO) and etc. tells the story that enterprise nowadays puts performance before anything. However, most enterprises fail to integrate the similar concepts behind evaluation indexes and ISO like quality goal, quality review, human resource, and process management and treat each index as an independent system. This has caused enterprises serious waste and cost. Also, there is always lacked an objective evaluation method between human resource development and performance management. Enterprise performance management system is often criticized for its isolation from the real competitive environment and helplessness in staff encouragement or efficiency improvement. The fact that the current quality system and performance management system cannot reflect customer¡¦s voice, the main source of profit improvement, undermines the benefits of system implementation and is against the expectation of persistent development. Through in-depth interview, this study specifies how enterprises in LCD industry implement performance evaluation and ISO9001: 2000 and clarify the correlation between these internal systems and the disconnection occurred. Based on bibliography and theory study, then conduct to an integrated operation system that has two major parts, including mixed-construction and process management. The process oriented management flow could easy to connect the performance evaluation gap between enterprise and customer concern. The mixed-construction could meet the performance evaluation request of LCD industry which is customers¡¦ satisfaction¡Bspeed and competence. Through this kind of operation system, enterprise could easy to put customer concern in the enterprise internal system and also could achieve a closed loop of continuous improvement. That is also called as system synergy. In enterprises operation, cost reduction stands as important as profit seeking. The concept of integration of performance management system and ISO9001¡G2000 quality management system indicated in this research provides a way to meet the targets of performance and cost while promoting employee satisfaction, enterprise competitiveness and customer satisfaction.

Mελετάται το ζήτημα της διαχείρισης και προστασίας των Πνευματικών Δικαιωμάτων στον ψηφιακό κόσμο. Συγκεκριμένα, προτείνονται τα Συστήματα Ψηφιακής Διαχείρισης Δικαιωμάτων (DRM), ως μέσα προστασίας της νομοθετικής κατοχύρωσης των πνευματικών δικαιωμάτων (copyright) και υποστήριξης της διανομής του ψηφιακού περιεχομένου μέσω των δικτύων και του διαδικτύου, για την αποφυγή περιπτώσεων παραβίασης του νόμου της Πνευματικής Ιδιοκτησίας. Yλοποιήθηκε ένα πληροφοριακό σύστημα που ικανοποιεί τις λειτουργικές και τις τεχνικές προδιαγραφές των οντοτήτων που εμπλέκονται στο ζήτημα της διαχείρισης και της προστασίας των πνευματικών δικαιωμάτων. Η υλοποίηση του συστήματος έγινε με χρήση ανοικτών τεχνολογιών και ενός συστήματος διαχείρισης περιεχομένου (Drupal), ακολουθώντας διεθνή πρότυπα και πληρώντας κριτήρια ποιότητας και ευχρηστίας. / The issue of Management and Protection of Intellectual Rights is analysed in this project. Especially, Digital Rights Management Systems (DRMS)proposed as a way of legal protection of the copyright and support of the distribution of digital content throughout the internet, in order to avoid the infringement of the Intellectual Property Law. A system which satisfy the functional and technological requirements of the ontologies that include in the management and protection of the intellectual rights is implemented. Open technologies, international prototypes and a content management system (Drupal), are used for the implementation of a system of high quality and usability.

Hochwertige Schulungsmaterialien für die unternehmensinterne Weiterbildung sind ein erster wichtiger Schritt hin zu einem effektiven Wissensmanagement. Einmal erstellt, können digitale Lerninhalte immer wieder eingesetzt werden. Allerdings ist die Pflege und Anpassung an die Anforderungen verschiedener Zielgruppen und Auslieferungsformate mit herkömmlicher E-Learning-Autorensoftware sehr aufwändig. Nicht so bei serverbasierter Software – sie ermöglicht die Planung, Erstellung, Auslieferung, Verwaltung und Pflege wiederverwendbarer digitaler Lernmaterialien. Dies ist der Ausgangspunkt für eine Vielzahl individueller Weiterbildungsangebote – ohne erneuten Aufwand für die Erstellung der Lerninhalte.