<p>En enkätundersökning har genomförts bland landets naturbruksgymnasier för att undersöka deras uppfattningar om distansutbildning och lärplattform. Syftet med undersökningen var att beskriva och försöka skapa en bättre förståelse, samt att ta reda vilka faktorer som är viktiga att tänka på när en gemensam lärplattform och webbaserat lärande implementeras. Uppsatsen avslutas med några rekommendationer. Enkäten skickadesvia e-post, tillsammans med en film och ett dokument som visade ett exempel på en distanskurs. Enkätsvaren analyserades i huvudsak kvalitativt med hjälp av ett fenomenografiskt perspektiv. Resultatet visade att det finns goda möjligheter på skolorna för både distansutbildning och ett samarbete om en gemensam lärplattform. Det finns dock ingen enighet kring syftet och nyttan med ett samarbete. Resultatet visade även att skolorna uppfattar att det finns både fördelar och nackdelar ur organisationens, lärarens och studentens perspektiv. Flexibilitet, den sociala kontakten, delaktighet vid förändringar och en blandad kursform är några faktorer man måste tänka på.</p>

On this thesis project, the LMS algorithm has been applied for speech noise filteringand different behaviors were tested under different circumstances by using Matlabsimulations and the LPC2378 ARM Processor, which does the task of filtering in realtime. The thesis project is divided into two parts: the theoretical and practical part. In the theoretical part there is a brief description of the different aspects of signalprocessing systems, filter theory, and a general description of the Least-Mean-SquareAdaptive Filter Algorithm. In the practical part of the report a general description of the procedure will besummarized, the results of the tests that were conducted will be analyzed, a generaldiscussion of the problems that were encounter during the simulations will be mention,and suggestion for the problems will be given.

In hands-free telephony and in teleconference systems, the main aim is to provide agood free voice quality when two or more people communicate from different places.The problem often arises during the conversation is the creation of acoustic echo. Thisproblem will cause the bad quality of voice signal and thus talkers could not hearclearly the content of the conversation, even thought lost the important information.This acoustic echo is actually the noise which is created by the reflection of soundwaves by the wall of the room and the other things exist in the room. The mainobjective for engineers is the cancellation of this acoustic echo and provides an echofree environment for speakers during conversation. For this purpose, scientists designdifferent adaptive filter algorithms. Our thesis is also to study and simulate theacoustics echo cancellation by using different adaptive algorithms.

In distance education, lack of face-to-face communication prevents instructors from observing students&rsquo / activities efficiently, especially in crowded sessions, and consequently they fail to effectively assess the performance of distant learners. On the other hand, in spite of being physically distant, instructor should monitor students&rsquo / activities and assess their performance effectively so that learners can be informed as quickly as possible of how well they are doing. This thesis aims to develop an e-learning tool for distance education that integrates asynchronous and synchronous learning environments to offer an enriched e-learning platform. The tool enables instructor to keep track of students&rsquo / activities, assesses learners&rsquo / participation during online synchronous sessions dynamically, and provides asynchronous access to assessment data after the lectures. In this way, it is aimed to monitor performance of distant learners by the instructor more efficiently.

In this thesis, we investigate the use of adaptive antenna algorithms for OFDM systems to suppress interference in various channel conditions including narrowband and wideband interference, flat and frequency selective fading. We propose a novel frequency-domain beamformer, based on the linearly constrained modified constant modulus hybrid LMS (LCMCM-HLMS) algorithm for OFDM systems to improve the performance of interference suppression in AWGN channel with narrowband interference, Rayleigh fast fading channel with phase distortion, and the multipath environment. To verify the merits of the frequency-domain beamformer, the effect due to narrowband interference and random phase distortion are investigated. Moreover, to improve the performance of adaptive beamforming algorithm, the frequency-domain linearly constrained modified constant modulus hybrid LMS (LCMCM-HLMS) algorithm is proposed. Computer simulation results show that the proposed frequency-domain LCMCM-HLMS beamformer has good capability of interference supression in various environment, and can mitigate the phase distortion of channel. However, in the time-domain beamformer based on LMS [33], RLS ,LC-LMS and LC-FLS algorithm for OFDM systems, the performance may severely degraded under some situations. We will show that in terms of output SINR, beampatern, received signal constellation and mean square error (MSE), for narrowband interference suppression in AWGN channel, phase distortion in Rayleigh fast fading channel and the multipath environment.

<p>On this thesis project, the LMS algorithm has been applied for speech noise filteringand different behaviors were tested under different circumstances by using Matlabsimulations and the LPC2378 ARM Processor, which does the task of filtering in realtime. The thesis project is divided into two parts: the theoretical and practical part.</p><p>In the theoretical part there is a brief description of the different aspects of signalprocessing systems, filter theory, and a general description of the Least-Mean-SquareAdaptive Filter Algorithm.</p><p>In the practical part of the report a general description of the procedure will besummarized, the results of the tests that were conducted will be analyzed, a generaldiscussion of the problems that were encounter during the simulations will be mention,and suggestion for the problems will be given.</p>

<p>In hands-free telephony and in teleconference systems, the main aim is to provide agood free voice quality when two or more people communicate from different places.The problem often arises during the conversation is the creation of acoustic echo. Thisproblem will cause the bad quality of voice signal and thus talkers could not hearclearly the content of the conversation, even thought lost the important information.This acoustic echo is actually the noise which is created by the reflection of soundwaves by the wall of the room and the other things exist in the room. The mainobjective for engineers is the cancellation of this acoustic echo and provides an echofree environment for speakers during conversation. For this purpose, scientists designdifferent adaptive filter algorithms. Our thesis is also to study and simulate theacoustics echo cancellation by using different adaptive algorithms.</p>

Η εργασία αυτή αποτελεί συνέχεια μιας προσπάθειας για την ανάπτυξη της πύλης WEP (Web Engineering Resources Portal). Πρόκειται για ένα Μοντέλο Αναφοράς και μια Πύλη Πόρων που φιλοδοξεί να αποτελέσει ένα σημαντικό εργαλείο για το web engineering, αλλά και αναφορά στην ανάπτυξη εφαρμογών / πληροφοριακών συστημάτων παγκοσμίου ιστού και οδηγό στην ανεύρεση και κατανόηση τεχνολογιών και εργαλείων. Το κομμάτι με το οποίο θα ασχοληθούμε εδώ αφορά το τελευταίο μέρος και τον εκπαιδευτικό χαρακτήρα που επιθυμούμε να προσδώσουμε στην πύλη. Συνοπτικά, η διπλωματική εργασία κινείται σε τρεις άξονες: Πρώτον, στη μελέτη σύγχρονων δυνατοτήτων συλλογής πληροφορίας για την επιλογή των κατάλληλων εργαλείων για εισαγωγή στην πύλη και την ανάπτυξη της δικής μας μεθοδολογίας. Η διαρκής και ραγδαία αύξηση του όγκου των δεδομένων κατέστησε εμφανές το πρόβλημα της ευρέσεως και εξαγωγής της ''χρήσιμης'' ή ''επιθυμητής'' πληροφορίας, καθώς για κάθε κατηγορία ιστοεφαρμογών υπάρχει μια πληθώρα εργαλείων ανάπτυξης (τα οποία μάλιστα διαρκώς ανανεώνονται) καθιστώντας τη διαδικασία επιλογής των καταλληλότερων ιδιαίτερα επίπονη και χρονοβόρα. Δεύτερον, στην εφαρμογή της παραπάνω μεθοδολογίας εργασίας με στόχο την εισαγωγή των αντίστοιχων εργαλείων που προέκυψαν με τη μετατροπή της πληροφορίας σε XML για τη δόμηση της πύλης WEP. Εξηγούμε πως έγινε η εισαγωγή και διαχείριση περιεχομένου με χρήση της τεχνολογίας XML και πως καταλήγουμε στην υλοποίηση των παραπάνω μέσα από την πλατφόρμα του stringbeans. Τρίτον στον εκπαιδευτικό χαρακτήρα της Πύλης. Αναφερόμαστε στις έννοιες του e-learning, και τις διάφορες εναλλακτικές που υπάρχουν στο χώρο της ηλεκτρονικής μάθησης στην εποχή του Web 2.0, όπου οι χρήστες συμμετέχουν ενεργά στη συγγραφή του εκπαιδευτικού υλικού. Αναλύουμε τα χαρακτηριστικά των PLE (Personal Learning Environments) και των LMS (Learning Management Systems) και εκθέτουμε πλεονεκτήματα και μειονεκτήματά τους. Τέλος, καταλήγουμε σε μια γενική αξιολόγηση της προσπάθειάς μας, καταγράφοντας τα αποτελέσματα και τους στόχους που υλοποιήθηκαν, τα συμπεράσματα και τις προτάσεις μας. / This paper is a follow up of the previous work concerning the Web Engineering Resources Portal (shortly WEP). It consists of a Reference Model and a Resources Portal. The aim of WEP is to provide a tool for web engineering as well as a reference for the development of applications / information systems and a guide for finding and understanding web engineering technologies and tools. Here we deal with that last part and the educational aspect of WEP which we are trying to achieve. Briefly, the thesis involves three parts: Firstly, the study of modern possibilities for collecting and importing information regarding the choice of suitable tools and the development of our own methodology. The rapid growth of data volume rendered obvious the problem of finding and extracting of ''useful'' or ''desirable '' information, since there is an abundance of development tools (which are indeed constantly renewed) for every category of web application making the process of choosing the most suitable ones particularly laborious and time-consuming. Secondly, it refers to the enforcement of the above methodology aiming at the import of resultant tools with the transformation of information in XML for the layout of WEP. We explain the way the import and management of content using XML technology is completed and we come to the adaptation and implementation phase through the Stringbeans framework. Thirdly we try to highlight the educational character of WEP portal. The concept of e-learning is described and the various alternatives at the age of Web 2.0, where the users participate actively in the writing of educational material are taken into consideration. Furthermore, we analyze the characteristics of PLE (Personal Learning Environments) and LMS (Learning Management Systems) quoting advantages and disadvantages of both. Finally, we lead to a general evaluation of our effort, mentioning the results and the objectives that were achieved, the conclusions and our proposals for the future.

The design of a battery-powered, portable headphone active noise control system with TI TMS320C5416 DSP is described. The preliminary implementation of the system on a C5416 DSK is also explained. The problems of fixed-point implementation are described and solutions are proposed. Sign-sign Fx-LMS algorithm with a dead-zone is introduced and used as the adaptation algorithm. Effective use of dynamic range to improve the accuracy in filtering operations is discussed. Details of the designed battery-powered DSP board are given and board software development process is explained. The DSK system and designed portable system is compared against two commercially available analog systems under three different types of noises / composition of tones, drill noise and propeller plane cabin noise. The results reveal that adaptive system has better overall performance.

En enkätundersökning har genomförts bland landets naturbruksgymnasier för att undersöka deras uppfattningar om distansutbildning och lärplattform. Syftet med undersökningen var att beskriva och försöka skapa en bättre förståelse, samt att ta reda vilka faktorer som är viktiga att tänka på när en gemensam lärplattform och webbaserat lärande implementeras. Uppsatsen avslutas med några rekommendationer. Enkäten skickadesvia e-post, tillsammans med en film och ett dokument som visade ett exempel på en distanskurs. Enkätsvaren analyserades i huvudsak kvalitativt med hjälp av ett fenomenografiskt perspektiv. Resultatet visade att det finns goda möjligheter på skolorna för både distansutbildning och ett samarbete om en gemensam lärplattform. Det finns dock ingen enighet kring syftet och nyttan med ett samarbete. Resultatet visade även att skolorna uppfattar att det finns både fördelar och nackdelar ur organisationens, lärarens och studentens perspektiv. Flexibilitet, den sociala kontakten, delaktighet vid förändringar och en blandad kursform är några faktorer man måste tänka på.