The sphere of services started to develop very actively in the last century. Nowadays this sector of economics gained the dominant positions: currently those services compound more than two thirties of the World’s Gross National Product (GNP). Approximately seventy percent of the GNP is obtained in sector of the services. Moreover, this sector is growing much faster (16 percent per year) than trade in services (7 percent per year only). Currently more than seventy percent of the employees are working in the sector of the services, and this part practically contains all the development of employment. According to the data of the Statistic Department of Lithuania and the Bank of Lithuania, during period 2000 – 2006 the services became the key in economical sector in the structure of the Lithuanian economy, and it compounds the biggest part of surplus. Despite this fast development of the sector of the services, many problems that limit this market are rising up, for example, obstructions for Small and Medium-Sized Enterprises (SME), the problems with innovations, the efficiency of the employment, the obstacles that influence the establishment of the enterprises. It is necessary to make the comprehensive analysis of the sector of the services in order to solve those problems. The conception of the service, groups of the services traded in the international market and their accounting, the development of the services of the international market and its changes, the factors that... [to full text]

Ce mémoire de maîtrise présente une nouvelle approche non supervisée pour détecter et segmenter les régions urbaines dans les images hyperspectrales. La méthode proposée n ́ecessite trois étapes. Tout d’abord, afin de réduire le coût calculatoire de notre algorithme, une image couleur du contenu spectral est estimée. A cette fin, une étape de réduction de dimensionalité non-linéaire, basée sur deux critères complémentaires mais contradictoires de bonne visualisation; à savoir la précision et le contraste, est réalisée pour l’affichage couleur de chaque image hyperspectrale. Ensuite, pour discriminer les régions urbaines des régions non urbaines, la seconde étape consiste à extraire quelques caractéristiques discriminantes (et complémentaires) sur cette image hyperspectrale couleur. A cette fin, nous avons extrait une série de paramètres discriminants pour décrire les caractéristiques d’une zone urbaine, principalement composée d’objets manufacturés de formes simples g ́eométriques et régulières. Nous avons utilisé des caractéristiques texturales basées sur les niveaux de gris, la magnitude du gradient ou des paramètres issus de la matrice de co-occurrence combinés avec des caractéristiques structurelles basées sur l’orientation locale du gradient de l’image et la détection locale de segments de droites. Afin de réduire encore la complexité de calcul de notre approche et éviter le problème de la ”malédiction de la dimensionnalité” quand on décide de regrouper des données de dimensions élevées, nous avons décidé de classifier individuellement, dans la dernière étape, chaque caractéristique texturale ou structurelle avec une simple procédure de K-moyennes et ensuite de combiner ces segmentations grossières, obtenues à faible coût, avec un modèle efficace de fusion de cartes de segmentations. Les expérimentations données dans ce rapport montrent que cette stratégie est efficace visuellement et se compare favorablement aux autres méthodes de détection et segmentation de zones urbaines à partir d’images hyperspectrales. / This master’s thesis presents a new approach to urban area detection and segmentation in hyperspectral images. The proposed method relies on a three-step procedure. First, in order to decrease the computational complexity, an informative three-colour composite image, minimizing as much as possible the loss of information of the spectral content, is computed. To this end, a non-linear dimensionality reduction step, based on two complementary but contradictory criteria of good visualization, namely accuracy and contrast, is achieved for the colour display of each hyperspectral image. In order to discriminate between urban and non-urban areas, the second step consists of extracting some complementary and discriminant features on the resulting (three-band) colour hyperspectral image. To attain this goal, we have extracted a set of features relevant to the description of different aspects of urban areas, which are mainly composed of man-made objects with regular or simple geometrical shapes. We have used simple textural features based on grey-levels, gradient magnitude or grey-level co-occurence matrix statistical parameters combined with structural features based on gradient orientation, and straight segment detection. In order to also reduce the computational complexity and to avoid the so-called “curse of dimensionality” when clustering high-dimensional data, we decided, in the final third step, to classify each individual feature (by a simple K-means clustering procedure) and to combine these multiple low-cost and rough image segmentation results with an efficient fusion model of segmentation maps. The experiments reported in this report demonstrate that the proposed segmentation method is efficient in terms of visual evaluation and performs well compared to existing and automatic detection and segmentation methods of urban areas from hyperspectral images.

Το αντικείμενο της παρούσας διδακτορικής διατριβής είναι η οικολογική αξιολόγηση δύο ποτάμιων οικοσυστημάτων του Αχέροντα και του Λούρου, με βάση τις κοινότητες υδρόβιων μακροφύτων, την ποιότητα του νερού και τα υδρογεωμορφολογικά χαρακτηριστικά, καθώς και η ανάπτυξη και η οριστικοποίηση μεθοδολογίας για τη συλλογή, την επεξεργασία, την ανάλυση και την αξιολόγηση των δεδομένων πεδίου προσαρμοσμένης και εφαρμόσιμης στις ελληνικές συνθήκες. Οι επιμέρους στόχοι της διδακτορικής διατριβής διακρίνονται σε 4 επί μέρους κεφάλαια. Το πρώτο κεφάλαιο (Κεφάλαιο Α) αφορά τη διερεύνηση των αβιοτικών παραμέτρων που επηρεάζουν την κατανομή των υδρόβιων μακροφύτων κατά μήκος των δύο λεκανών απορροής. Στο δεύτερο κεφάλαιο (Κεφάλαιο Β) πραγματοποιείται διερεύνηση της δομής της παρόχθιας ζώνης και εκτίμηση των βασικών προτύπων οικολογικής διαβάθμισης και ανθρώπινης παρέμβασης. Στο τρίτο κεφάλαιο (Κεφάλαιο Γ) πραγματοποιείται αβιοτική τυπολογική διάκριση των θέσεων δειγματοληψίας με σκοπό τη μείωση της χωρικής διακύμανσης, έλεγχο της διαχρονικής και εποχικής διακύμανσης στην κατανομή των υδρόβιων μακροφύτων και καθορισμός των κοινοτήτων αναφοράς σε κάθε τμήμα του ποτάμιου οικοσυστήματος. Τέλος στο τέταρτο κεφάλαιο (Κεφάλαιο Δ) δίνεται η μεθοδολογία ανάπτυξης του συστήματος αξιολόγησης των επιπτώσεων των υδρομορφολογικών τροποποιήσεων στη σύνθεση και αφθονία των υδρόβιων και των παρόχθιων ειδών και η δημιουργία του Πολυμετρικού Δείκτη Μακροφύτων. Τα δεδομένα συλλέχθηκαν από συνολικά 32 θέσεις δειγματοληψίας οι οποίες επιλέχθηκαν με κριτήρια 1) την κάλυψη ευρείας διαβάθμισης χρήσεων γης, 2) την επιλογή περισσοτέρων του ενός τμημάτων με παρόμοια γεωμορφολογικά χαρακτηριστικά, 3) τη σταθερή απόσταση μεταξύ των θέσεων δειγματοληψίας, 4) την ομοιογένεια των τμημάτων και τέλος 5) την προσβασιμότητα στα σημεία δειγματοληψίας καθ’ όλη τη διάρκεια της παρακολούθησης. Με βάση τα πιο πάνω κριτήρια επιλέχθηκαν 15 θέσεις δειγματοληψίας στη λεκάνη απορροής του ποταμού Αχέροντα [11 Αχέροντας (A1-8 & A11-13), 1 Κωκυτός (A9), 1 Βουβό Ρέμα (A15), 2 αρδευτικά κανάλια (A10 & A14)] και 17 Θέσεις Δειγματοληψίας στη λεκάνη απορροής του ποταμού Λούρου (S1-17). Η περιοχή αξιολόγησης περιλαμβάνει ένα ομοιογενές τμήμα ποταμού μήκους 100 m, το οποίο χωρίστηκε σε τρία επί μέρους τμήματα: α) το τμήμα της κοίτης το οποίο καλύπτεται με νερό, β) τα κράσπεδα, δηλαδή το ενεργό τμήμα της κοίτης γ) την παρόχθια-δασική ζώνη. Για τη συλλογή και την αξιολόγηση της υδρόβιας και παρόχθιας βλάστησης πραγματοποιήθηκαν εποχικές δειγματοληψίες κατά τη διάρκεια των βλαστητικών περιόδων των ετών 2005-2007 και η αφθονία ειδών καταγράφηκε με την 5-βάθμια κλίμακα DAFOR (5: κυριαρχία και 1: απουσία). Στο πεδίο μετρήθηκαν επίσης οι φυσικοχημικές παράμετροι του νερού (pH, διαλυμένο οξυγόνο, θερμοκρασία, αγωγιμότητα, ταχύτητα νερού και μέσο βάθος νερού) και συλλέχθηκαν δείγματα επιφανειακού νερού για χημικές αναλύσεις θρεπτικών αλάτων αζώτου (ΝΟ3-Ν, ΝΟ2-Ν, ΝΗ4-Ν) και φωσφόρου (PO4-P & TP), Chl-a και αλκαλικότητας. Επίσης καταγράφηκαν στο πεδίο και υπολογίστηκαν στο εργαστήριο υδρογεωμορφολογικά στοιχεία και δεδομένα τοπίου τα οποία αφορούν τόσο την περιοχή αξιολόγησης όσο και όλη τη λεκάνη απορροής. Για τη στατιστική επεξεργασία των δεδομένων χρησιμοποιήθηκαν 1) Ιεραρχική Ανάλυση Συστάδων για βιοτική τυπολογία των υδρόβιων μακροφύτων κατά μήκος των ποταμών και για τον προσδιορισμό της δομής της παρόχθιας βλάστησης, 2) Ανάλυση Ειδών Δεικτών (ISA), για την περιγραφή της ιεραρχικής δομής της κάθε ομάδας και για τη διάκριση των σημαντικών Ειδών-Δεικτών (IndSps), και 3) Ταξιθέτηση όπου χρησιμοποιήθηκαν τόσο έμμεσες όσο και άμεσες αναλύσεις διαβάθμισης. Στις έμμεσες αναλύσεις διαβάθμισης χρησιμοποιήθηκαν α) Ανάλυση Κύριων Συνιστωσών (PCA), για τον προσδιορισμό των Γεωμορφολογικών Ενοτήτων και στον Καθορισμό της κλίμακας πιέσεων και β) Βελτιωμένη Ανάλυση Αντιστοιχιών (DCA), για τη χωρική κατανομή της αφθονίας των ειδών και τον έλεγχος των εποχικών και διαχρονικών διακυμάνσεων των κοινοτήτων αναφοράς. Ως άμεσες αναλύσεις διαβάθμισης χρησιμοποιήθηκαν α) Ανάλυση Πλεονασμού (RDA), για συσχέτιση των φυσικοχημικών χαρακτηριστικών του νερού με τα είδη δείκτες και β) Ανάλυση Κανονικών Αντιστοιχιών (CCA), για συσχέτιση των γεωμορφολογικών παραμέτρων με τα είδη-δείκτες και τον καθορισμό κύριων μεταβλητών υποβάθμισης της παρόχθιας ζώνης. Τα αποτελέσματα έδειξαν ότι κατά μήκος των δύο λεκανών απορροής διακρίνονται έξι Ομάδες Βλάστησης με παρόμοιο περιβαλλοντικό πρότυπο (πηγές-εκβολές). Στις ορεινές περιοχές και των δύο λεκανών απορροής (Αχέροντα και Λούρου) κυριαρχούν τα είδη Pteridium aquilinum, είδη βρυόφυτων και είδη του γένους Carex, C. acuta για τον ποταμό Αχέροντα και C. pendula για τον ποταμό Λούρο. Στο μέσο ρου των ποταμών διακρίθηκαν 4 διαφορετικές ομάδες βλάστησης. Ο διαφορετικός βαθμός ανθρωπογενούς τροποποίησης των εκβολών στις δύο λεκάνες απορροής αντανακλά και στη σύνθεση των φυτοκοινοτήτων όπου στις εκβολές του ποταμού Αχέροντα κυριαρχούν χλωροφύκη και το ανθεκτικό είδος Potamogeton pectinatus ενώ στον ποταμό Λούρο οι εκβολές χαρακτηρίζονται από την απουσία χλωροφυκών και την κυριαρχία του είδους Potamogeton nodosus. Οι σημαντικότεροι φυσικοχημικοί παράγοντες οι οποίοι επηρεάζουν την κατανομή των υδρόβιων μακροφύτων κατά μήκος των λεκανών απορροής της περιοχής μελέτης είναι: το pH, η αγωγιμότητα, η θερμοκρασία νερού, η μέση ταχύτητα νερού, οι συγκεντρώσεις των αλάτων αζώτου (ΝΟ3-Ν, ΝΗ4-Ν, ΝΟ2-Ν) και ορθοφωσφορικών (PO4-P) και Chl-a. Ενώ οι σημαντικότεροι γεωμορφολογικοί παράγοντες είναι: το υψόμετρο, το υπόστρωμα κοίτης, το πλάτος της κοίτης, η σκίαση της κοίτης, ο τύπος ενδιαιτήματος και το βάθος του νερού. Η διερεύνηση της δομής της παρόχθιας ζώνης έδειξε την ύπαρξη 4 διαφορετικών ομάδων παρόχθιας βλάστησης. Οι ορεινές περιοχές και άνω μέσος ρους και των δύο λεκανών απορροής χαρακτηρίζεται από την κυριαρχία των ειδών Platanus orientalis και Quercus coccifera. Οι βασικές τροποποιήσεις που δέχονται οι περιοχές αυτές αφορούν μεταβολές σε τοπικό επίπεδο γεγονός που επιβεβαιώνεται από τις υψηλές τιμές δείκτη QBR. Οι πεδινές περιοχές χαρακτηρίζονται από την κυριαρχία των ειδών Salix alba και Populus alba. Οι σημαντικότερες πιέσεις που δέχεται το πεδινό τμήμα των ποταμών αφορούν τις γεωργικές δραστηριότητες, τη δημιουργία τεχνικών αναχωμάτων, την ενίσχυση της όχθης, τις αμμοχαλικοληψίες, τη διευθέτηση και την ευθυγράμμιση της όχθης. Το είδος Phragmites australis χαρακτηρίζει τις εκβολές των ποταμών, ενώ σημαντική ήταν η αφθονία των ειδών Arundo donax και του εισαγόμενου είδους Eucalyptus camaldulensis. Σύμφωνα με τα αποτελέσματα η αφθονία των ειδών ήταν χαμηλή σε όλες τις Ομάδες Βλάστησης. Εφαρμόστηκαν επίσης οι δείκτες: QBR ο οποίος αποτελεί μέτρο αξιολόγησης της ποιότητας της παρόχθιας ζώνης, HQA όπου αποτελεί δείκτη αξιολόγησης της οικολογικής ποιότητας του ποτάμιου ενδιαιτήματος και HMS ο οποίος είναι δείκτης ανθρωπογενούς τροποποίησης του ενδιαιτήματος. Τα αποτελέσματα από την εφαρμογή των πιο πάνω δεικτών έδειξαν ότι η οικολογική ακεραιότητα παρόχθιας ζώνης αυξάνει τη συνολική οικολογική ποιότητα. Σύμφωνα με τις υδρογεωμορφολογικές μεταβλητές, οι οποίες εξετάστηκαν, οι θέσεις δειγματοληψίας ομαδοποιηθήκαν σε τρεις Γεωμορφολογικές Ενότητες οι οποίες αντιστοιχούν στο Ορεινό, Πεδινό και Εκβολικό Τμήμα των ποταμών. Σε κάθε Γεωμορφολογική Ενότητα πραγματοποιήθηκε ανάλυση πιέσεων και διακρίθηκαν οι σταθμοί αναφοράς οι οποίοι για το ορεινό τμήμα ήταν 7, στο πεδινό 3 ενώ στο εκβολικό τμήμα μόνο 2 σταθμοί χαρακτηρίστηκαν ως περιοχές αναφοράς. Σε κάθε Γεωμορφολογική Ενότητα διερευνήθηκαν οι εποχικές και διαχρονικές μεταβολές στη σύνθεση των κοινοτήτων αναφοράς και προσδιορίστηκε δομή τους. Τα αποτελέσματα έδειξαν, ότι η σύνθεση των κοινοτήτων αναφοράς στο πεδινό τμήμα των ποταμών φαίνεται να παραμένουν σταθερές στις φυσικές διακυμάνσεις. Από την άλλη, οι μικρές διαφορές οι οποίες καταγράφηκαν στο ορεινό και εκβολικό τμήμα των ποταμών οφείλονται κυρίως στην όψιμη Άνοιξη και στις υψηλές θερμοκρασίες που επικρατούν κατά τους καλοκαιρινούς μήνες και εντοπίζονται στο μειωμένο αριθμό των βρυοφύτων και πτεριδοφύτων αντίστοιχα. Τέλος σύμφωνα τα αποτελέσματα η περίοδος διεξαγωγής των δειγματοληψιών προσδιορίζεται ανάμεσα στο χρονικό διάστημα μεταξύ τέλος Απριλίου και τέλος Σεπτεμβρίου αφού σε αυτό το χρονικό διάστημα οποιαδήποτε επίσκεψη στο πεδίο αναμένεται να δώσει την ίδια σύνθεση των κοινοτήτων αναφοράς. Διερευνήθηκαν, στο μεγαλύτερο δυνατό βαθμό, όλες οι πιθανές παράμετροι και πιέσεις, οι οποίες επηρεάζουν τη σύνθεση και την κατανομή υδρόβιων μακροφύτων κατά μήκος των λεκανών απορροής. Οι σημαντικότερες πιέσεις που δέχεται η περιοχή μελέτης επηρεάζουν κυρίως τα υδρομορφολογικά χαρακτηριστικά του οικοσυστήματος. Ως πιο αξιόπιστος και ολιστικός τρόπος αξιολόγησης της οικολογικής κατάστασης της περιοχής μελέτης επιλέχθηκε η Πολυμετρική προσέγγιση. Σαν πίεση επιλέχθηκε η υδρομορφολογική τροποποίηση. Συνολικά, διερευνήθηκαν 86 υποψήφιες μετρικές οι οποίες ανήκουν σε 5 κατηγορίες: 1) Αφθονίας/Ποικιλότητας, 2) Τροφικής κατάστασης, 3) Σύνθεσης φυτικών κοινοτήτων, 4) Ποιότητας Δομής της παρόχθιας ζώνης και 5) Ευαισθησίας/Ανοχής, οι οποίες προέρχονται από τις βιοκοινότητες του υγρού δίαυλου, της ενεργής κοίτης και της όχθης. Ο καθορισμός της κλίμακας πιέσεων πραγματοποιήθηκε με τη χρήση της Ανάλυσης Κύριων Συνιστωσών (PCA) με 36 υδρομορφολογικές μεταβλητές υποβάθμισης σε 2 χωρικά επίπεδα: Μακροκλίμακας και Μικροκλίμακας. Στον τελικό Πολυμετρικό δείκτη συμπεριλήφθηκαν μόνο οι μετρικές οι οποίες ικανοποιούσαν συγκεκριμένα κριτήρια. Τα κριτήρια αυτά αφορούσαν: την εκπλήρωση του κριτηρίου από την εφαρμογή των θηκογραμμάτων με απολήξεις (δηλαδή εξαιρούνται οι μετρικές οι οποίες έχουν στενό εύρος τιμών, πολλές ακραίες τιμές και πολλές απόμακρες παρατηρήσεις), την αποφυγή αλληλεπικαλυπτόμενων πληροφοριών (Spearman ǀrǀ>0,800) και την υψηλή συσχέτιση με τις κλίμακες πιέσεων (Spearman ǀrǀ>0,500). Συνολικά από τις 86 υποψήφιες μετρικές οι 6 θεωρήθηκαν ως κεντρικές μετρικές αφού ικανοποίησαν όλα τα πιο πάνω κριτήρια. Οι κεντρικές μετρικές είναι: 1) Δείκτης IBMR, 2) Δείκτης QBR, 3) Αριθμός Βρυοφυτικών taxa, 4) % Είδη Αναφοράς, 5) % Νιτρόφιλα είδη και 6) % Ελοφυτικά είδη (Phe_herbids). Ο Πολυμετρικός Δείκτης Μακροφύτων (Multimetric Macrophyte Index-MMI) είναι ο αριθμητικός μέσος των 6 κανονικοποιημένων «κεντρικών» μετρικών. Κανονικοποίηση καλείται η προσαρμογή του εύρους τιμών της κάθε μετρικής στο ενδεικτικό όριο από 0 μέχρι 1. Σημαντικό σημείο στην κανονικοποίηση των μετρικών είναι ο καθορισμός του ανώτερου (upper anchor) και κατώτερου ορίου (lower anchor) της κάθε «κεντρικής» μετρικής. Το ανώτερο και το κατώτερο όριο δείχνουν το ενδεικτικό εύρος της κάθε μετρικής όπου το ανώτερο όριο (anchor) αντιστοιχεί στην τιμή της μετρικής κάτω από τις συνθήκες αναφοράς. Στην παρούσα εργασία για το ανώτερο όριο κάθε μετρικής επιλέχθηκε το 75ο εκατοστημόριο (percentile) των μη διαταραγμένων περιοχών και για το κατώτερο όριο το 5ο εκατοστημόριο (percentile) των διαταραγμένων περιοχών. Για την αξιολόγηση της οικολογικής ποιότητας, των θέσεων δειγματοληψίας, με βάση τον Πολυμετρικό Δείκτη Μακροφύτων, απαιτείται ο καθορισμός των ορίων μεταξύ των 5 ποιοτικών κλάσεων όπως απαιτεί η Οδηγία Πλαίσιο για τα Ύδατα 2000/60/ΕΕ. Τα όρια του δείκτη καθορίστηκαν υπολογίζοντας αρχικά το όριο μεταξύ της «Υψηλής»/«Καλής» οικολογικής κατάστασης το οποίο ορίστηκε ως το 25o εκατοστημόριο μη διαταραγμένων περιοχών (0,623). Το υπόλοιπο εύρος τιμών χωρίστηκε σε τέσσερις ίσες κλάσεις. Τα αποτελέσματα έδειξαν, ότι ο ΜΜΙ δίνει πολύ καλή ένδειξη της οικολογικής κατάστασης των μεσαίου μεγέθους πεδινών ποταμών της Δυτικής Ελλάδας (RM-2). Σύμφωνα με τα αποτελέσματα το 29,6% των θέσεων δειγματοληψίας (8 θέσεις) ταξινομήθηκαν στην Υψηλή οικολογική κατάσταση, το 4% (14 θέσεις) στην Καλή οικολογική κατάσταση, το 22,3% (6 θέσεις) στην Μέτρια, το 29,6% (8 θέσεις) στην Φτωχή και μόνο το 3,7% (1 θέση) χαρακτηρίστηκε ως Κακής Οικολογικής Ποιότητας. Η παρούσα Διδακτορική Διατριβή, αποτελεί µια πρώτη προσπάθεια στον Ελληνικό χώρο για δημιουργία ενός ολοκληρωμένου συστήματος παρακολούθησης της οικολογικής ποιότητας των ρεόντων υδάτων με χρήση των υδρόβιων μακροφύτων ως βιολογικών ποιοτικών στοιχείων. Η μεθοδολογία αναπτύχθηκε και εφαρμόστηκε πιλοτικά σε δύο λεκάνες απορροής στα μεσαίου μεγέθους πεδινά ποτάμια της Ηπείρου Αχέροντα και Λούρου ακολουθώντας πιστά τις απαιτήσεις και τις κατευθυντήριες γραμμές της Ευρωπαϊκής Οδηγίας Πλαίσιο για τα Ύδατα 2000/60/ΕΕ. Επίσης το σύστημα αξιολόγησης το οποίο προτείνεται αναπτύχθηκε με σκοπό την εφαρμογή του σε όλα τα παρόμοιου τύπου ποτάμια της Ελλάδας αφού τόσο ο κατάλογος με τις υποψήφιες μετρικές όσο και ο ίδιος ο πολυμετρικός δείκτης μπορεί να ελεγχθεί και σε άλλους τύπους ποταμών της Ελλάδας (RM-1, RM-3, RM-4 & RM-5). Τέλος, τα αποτελέσματα που προκύπτουν συμβάλλουν στην ορθολογικότερη διαχείριση και ανάδειξη των ποτάμιων ενδιαιτημάτων και στην εφαρμογή της περιβαλλοντικής πολιτικής του νερού στην Ελλάδα. / The main objective of the present thesis was the ecological assessment of two river basins, Acheron and Louros; based on aquatic plant communities, water quality and hydromorphological characteristics, as well as, the development of a methodology for collecting, analyzing and assessing field data, specific adapted to Greek conditions. The specific objectives of the doctoral thesis include: a) the investigation of abiotic parameters influencing the distribution of aquatic macrophytes along the two river basins (Chapter A); b) the investigation of riparian zone structure and the assessment of “key” environmental gradient and human intervention (Chapter B); c) abiotic typology for reducing the spatial variability, monitoring the temporal and seasonal variation in of aquatic macrophytes distribution, and determination of reference communities in each geomorphological unit of the riverine ecosystem (Chapter C), and d) the development of the Macrophyte Multimetric Index (MMI) which is described step by step in Chapter D. Data were collected from 32 sampling sites, which were chosen according to the following criteria: i) covering a wide gradient of land used i.e. from natural to artificial; ii) selection of more than one site with similar geomorphological characteristics; iii) the constant distance between sampling sites; iv) the homogeneity of the sampling sites, and v) the accessibility to the sampling points throughout the duration of monitoring. Based on the above criteria, 15 sites were selected along Acheron river basin [11, Acheron river (A1-8 & A11-13); 1, Cocytos (A9); 1, Vouvo Rema (A15); 2, irrigation canals (A10 & A14)]. Additionally, 17 sampling sites were selected along Louros river (S1-S15). The survey area was subdivided into 3 zones, a) the wetted part of the channel, b) the marginal-active channel and c) the riparian woodland plot. The survey area length was standardized at 100 m according to the widely accepted methods [e.g. Mean Trophic Rank, (MTR); Riparian Forest Quality, (QBR)]. On the other hand, the width of each plot includes the area between, the end of the active channel and the riparian woodland. The field surveys were conducted during the vegetation periods (April to September) of the years 2005 to 2007. The coverage of each macrophyte species was visually estimated using DAFOR 5-point scale (1: Rare, 2: Occasional, 3: Frequent, 4: Abundant and 5: Dominant). Also, water physicochemical parameters such as temperature, DO, pH, conductivity, were measured in situ using portable equipment (WTW340i/SET). Additionally, surface water samples were collected for determination of nutrients such as nitrate and nitrite nitrogen, total nitrogen, ammonium, phosphorus nutrients (soluble reactive phosphorus and total phosphorus), Chl-a, and alkalinity (HCO-3, CO3=). Nutrient samples were collected and analyzed according to APHA standard analytical method (APHA, 1989). For the statistical processing of the data were used: 1) Hierarchical cluster analysis (Bray-Curtis), for the biotic typology of macrophyte data along river basins and to determine the structure of the riparian vegetation; 2) Indicator Species Analysis, was used to describe the hierarchical structure of each group to distinguish the indicator species (Ind_Sps) for each vegetation group; 3) Ordination, which were used both Indirect and Direct gradient analyses. Indirect gradient analyzes were used: a) Principal Component Analysis (PCA), to identify Geomorphological Units and to determining the pressure gradients; and b) Detrended Correspondence Analysis (DCA), for researching the spatial distribution of species abundance, and for seasonal and inter-annual variability of the reference communities. For direct gradient analyzes were used: a) Redundancy Analysis (RDA), for correlation between, water physicochemical parameters and Indicator species; and b) Canonical Correspondence Analysis (CCA), for correlation between geomorphological characteristics and indicator species, as well as, to determine the key variables best explain the degradation of the riparian zone. The results showed that along the two river basins, six vegetation groups can be distinguished, with similar environmental gradient pattern (springs-estuaries). The dominant species for the upper part of Acheron and Louros river basins were: Pteridium aquilinum, bryophyte taxa and Carex species (C. acuta and C. pendula respectively). Moreover, four different vegetation groups were characterized the middle part of both river basins. The different degree of anthropogenic alteration of river estuaries (Acheron and Louros), reflects in the composition of the plant communities. The estuaries of Acheron were characterized by the dominant of green algae and the tolerant species Potamogeton pectinatus, while the estuaries of Louros river was characterized by the absence of green algae and the dominance of Potamogeton nodosus. The most important physicochemical variables that significantly affect the distribution of aquatic macrophytes along the river basins were: pH, conductivity, water temperature, and mean water velocity, concentrations of nitrogen nutrients (ΝΟ3-Ν, ΝΗ4-Ν, ΝΟ2-Ν) and orthophosphate (PO4-P), as well as, Chl-a. Whereas, the most important geomorphological factors were: altitude, bed substrate, channel width, channel shading, habitat type, water depth. Hierarchical cluster analysis distinguished five vegetation groups of the riparian zone of the study area. The following groups were indentified and characterized by the dominant riparian species. The upper reaches were characterized by the Vegetation Group Ia: Platanus orientalis and Ib: Quercus coccifera-P. orientalis; the middle reaches by II: Salix alba and Populus alba; and lowland areas until estuaries by III: Phragmites australis. Vegetation Group IV was characterized by the dominant of non native species Eucalyptus camaldulensis and the giant reed Arundo donax. According to the results, species abundance was low in all Vegetation Groups. Also, the applied indices Riparian quality assessment (QBR), Habitat Quality Assessment (HQA) and Habitat Modification Score (HMS) revealed that the ecological integrity of the riparian zone increases the overall ecological quality of the riparian ecosystem. According to the hydromorphological characteristics, the sampling sites were grouped into three Geomorphological Units: Upper –Middle reaches-Estuaries. In each Geomorphological Unit (GU) a pressure gradient analysis was performed, and the reference sites were identified. For GU I the number of reference sites was 7, for GU II 3 reference sites were identified, while, for the estuaries the number of the reference sites were only 2. Also in each GU the seasonal and inter annual changes in reference communities, were investigated, and the structure of the reference community was determined. The results showed that the composition of the reference communities in lowland rivers appears to remain constant in the physical fluctuations. On the other hand, the slight differences which were recorded, in the GU I, during spring and summer sampling, referred to the reduction of bryophytes. This reduction might be cause due to the late spring (May), at the upper part of Louros river. Also, differences were recorded between autumn and spring samplings, in the GU III (estuaries). Those differences referred to the reduction of pteridophytes, maybe due to the high temperatures that prevail during the summer months. Finally, the sampling period could be set between late April and late September, since, during this period, any field visit will give the same composition of the reference communities. We investigated, to the greatest possible degree, all the potential parameters and pressures, which could influence the composition and distribution of aquatic macrophytes along the river basins. The most significant effect, from the current pressures, in the studied area, is the alteration of the hydromorphological characteristics of the ecosystem. The Multimetric approach was chosen, as the most holistic and reliable evaluation method of the ecological status of the study area. A preliminary list of potential plant metrics was compiled from a review of the literature, and in situ observations of plant community patterns. The metrics were grouped into five categories, so that each one representing a different ecological aspect of aquatic and riparian plant communities: 1) Richness/Diversity, 2) Trophic status, 3) Composition, 4) Riparian Integrity, and 5) Sensitivity/Tolerance. A total of 86 metrics were tested, of which 7 belonged to the category of "Abundance/Diversity", 4 to the category of "Trophic” status, 46 metric referred to “Composition” of plant communities, 11 referred to "Riparian Integrity”, and finally, 18 belonged to “Sensitivity/Tolerance” category. The estimation of the pressure gradient was performed using Principal Component Analyses (PCAs), with 36 hydromorphological degradation variables in 2 spatial scales: macroscale and microscale. Candidate metrics, which can be identified as robust and most informative, are scrutinized further, in the process of selecting core metrics. To be selected as a core metric the following aspects have to be considered: 1) core metrics should cover different metric types (see above); 2) metrics should not give redundant information. Inter-correlation tests between candidate metrics were carried out to detect redundant metrics (threshold value Spearman’s r<0.800). In case of redundancy we further investigate: the correlation of each metric with stress gradient (threshold value Spearman’s r<0.05); the correlation of each of the pair of metrics with the other metrics in order to finally omit the one that showed the higher overall mean correlation; and how well they separate stressed from unstressed sampling sites (graphical analysis of box-whisker plots). The final index includes 6 metrics out of 86 candidated metrics. The core metrics are: 1) IBMR, 2) QBR, 3) Number of Bryophyte, 4) % Reference Species, 5) % Nitrophilous taxa and 6) % Helophyte taxa (Phe_herbids). The different numerical scales of each core metric (e.g. abundance class, number of individuals) were normalized to unitless scores between 0 and 1. The upper and lower anchors mark the indicative range of a metric. The upper anchor corresponds to the upper limit of the metric’s value under reference conditions, and it was set as the 75th of the unstressed sites. The lower anchor corresponds to the lower limit of the metric’s value under the worst attainable conditions and it was set as 5th percentile of stressed sites. The multimetric index was calculated as the arithmetic mean of the normalized metrics (Böhmer et al., 2004). The final Multimetric Index provides a score that represents the overall relationship between the combined values of the biological parameters observed for a given site and the expected value under reference conditions. This score is – as for single metrics – expressed as a numerical value between zero and one. This range can be subdivided into any number of categories corresponding to various levels of impairment. To determine the boundaries of Multimetric Index, the 25th percentile of the unstressed sites (0,623) was set as the boundary for the high/good ecological class. We propose quality classes with equal ranges, to provide five ordinal rating categories for assessment of impairment in accordance with the demands of the WFD. The application of Macrophyte Multimetric Index (MMI) in the medium lowland rivers of Greece led to the ecological classification in five quality classes. The results indicated that the 29.6% of the sampling sites (8 sites) were classified in High ecological status, 4% (4 sites) in Good ecological status; the 22.3% (6 sites) in Moderate, 29.6% (8 sites) in the Poor and only 3.7% (1 site) was characterized as Bad ecological quality. The current doctoral thesis was the first attempt in the Greece, for establishing an integrated monitoring system of ecological quality of running water ecosystems, using aquatic macrophytes as biological quality element. The methodology developed, was pilot implemented in two river basins, Acheron and Louros, in Epirus, following the requirements and guidelines of the European Water Framework Directive, 2000/60/EE. Also, the evaluation system was developed to be proposed for implementation at all similar river types of Greece, since both the list of candidate metrics and the Multimetric Index itself, can be tested in other types of Greek rivers (RM-1, RM-3, RM-4 & RM-5). Finally, the results, will contribute to the sustainable management and conservation of riverine ecosystems, as well as, to the implementation of the water environmental policy in Greece.

This article presents in general terms the nature and characteristics of some of the key legal institutions of taxation such as tax legal relationship, the principal tax liability and payment as means to cease the obligation (before the actions that can display the State for tax debt collection) and also explaining the most important legal policy issues that such institutions have received in Peru. / El presente artículo expone, de manera general, la naturaleza y características de algunas de las instituciones jurídicas fundamentales del Derecho Tributario, tales como la relación jurídico tributaria, la obligación tributaria principal y el pago, como modo de extinción de ésta (antes del inicio de los actos que puede desplegar el Estado para realizar la cobranza coactiva de los tributos); explicando –cuando corresponda– los aspectos normativos más importantes que regulan tales instituciones en el Perú.

The thesis describes fatherhood from the antic age until now. It defines the role play of the father in each historical periods of time and describes sources of influence which formed this role. The study is also focused on the influence in the catholic church and analysis from the church point of view. Subject of the thesis practical part is views of men on their role as fathers in a Prague suburb parish. It attempts to capture their fatherhood experience and to analyse it in relation to the fathers' attitude to the education of their children and material security. It focuses on ways of spending leisure time with their children, their education and comprehension and passing faith on them. It also analyses ways of the fathers' involvement in their households and child care.

A website with a good e-commerce design will positively influence a customer’s attitude, strengthen the trust of the customers towards the organisation, increase the satisfaction of the customer, draw consumers, and bring forth purchases/repeat purchases from them. The purpose of this study was to determine viable e-commerce opportunities for the Ficksburg Cherry Festival website. The study endeavoured to ascertain how the Ficksburg Cherry Festival could improve its website by identifying e-commerce opportunities for the Ficksburg Cherry Festival website. In this study a non-random self-administered survey approach was used where attendees were intercepted at the venue of the Ficksburg Cherry Festival and the exhibitors in their stalls. The existing Ficksburg Cherry Festival website was analysed for e-commerce features that are present and opportunities for further implementation of e-commerce features were identified with help from the attendees and exhibitors. The findings of this study presented a demographic profile and attendance characteristics of both the attendees and exhibitors, which the management team of the Ficksburg Cherry Festival can use to better market the festival using traditional and online communication for both attendees and exhibitors. The recommendations will assist the management of the festival to improve the website and to progress from a straightforward information-only website to a fully-developed e-commerce site, with positive effects for all the stakeholders. Similar South African festivals could find the research findings and recommendations of value for their own website development as well. / Business Management / M. Com. (Business Management)

The State as the representative of the victims of crime is expected to protect those vulnarable group of people with due regard to the rights of the perpetrators’s of crime. It is imperative that the law of general application which is aimed at protecting victims of crime, be sufficiently effective to protect the victims. The Criminal Procedure Act 51 of 1977 is aimed at assisting the police to conduct pre-trial criminal procedure in order to bring perpetrators of crime to book. Sections 36A, 36B, 36C and 37 (both previous and as amended) of the Criminal Procedure Act including chapter 5A of the South African Police Act, 1995 are explored in this dissertation. This dissertation examines the areas in the Criminal Procedure Act that make it problematic for the police to conduct efficient and effective crime detection through the ascertainment of bodily features of the suspected or accused person. The law in three foreign jurisdictions relating to this topic are investigated and compared in order to make recommendations and suggest possible solutions. / Criminal and Procedural Law / LL.M.

Made available in DSpace on 2014-12-17T14:56:07Z (GMT). No. of bitstreams: 1 JesseHNB_DISSERT.pdf: 2206144 bytes, checksum: 191ca3ce00f97e4019b5bdb2bc9ab914 (MD5) Previous issue date: 2012-10-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The vision is one of the five senses of the human body and, in children is responsible for up to 80% of the perception of world around. Studies show that 50% of children with multiple disabilities have some visual impairment, and 4% of all children are diagnosed with strabismus. The strabismus is an eye disability associated with handling capacity of the eye, defined as any deviation from perfect ocular alignment. Besides of aesthetic aspect, the child may report blurred or double vision . Ophthalmological cases not diagnosed correctly are reasons for many school abandonments. The Ministry of Education of Brazil points to the visually impaired as a challenge to the educators of children, particularly in literacy process. The traditional eye examination for diagnosis of strabismus can be accomplished by inducing the eye movements through the doctor s instructions to the patient. This procedure can be played through the computer aided analysis of images captured on video. This paper presents a proposal for distributed system to assist health professionals in remote diagnosis of visual impairment associated with motor abilities of the eye, such as strabismus. It is hoped through this proposal to contribute improving the rates of school learning for children, allowing better diagnosis and, consequently, the student accompaniment / A vis?o ? um dos cinco sentidos do corpo humano e, em crian?as, ? respons?vel por at? 80% da percep??o do mundo ao redor. Estudos revelam que 50% das crian?as com m?ltiplas defici?ncias possuem alguma defici?ncia visual, sendo que 4% de todas as crian?as s?o diagnosticadas com estrabismo. O estrabismo ? uma defici?ncia ocular associada ? capacidade de movimenta??o dos olhos, caracterizada por qualquer desvio no alinhamento ocular perfeito. Al?m do aspecto est?tico, a crian?a pode relatar vista emba?ada ou dupla . Problemas oftalmol?gicos n?o diagnosticados corretamente s?o motivos de muitos abandonos da escola. O Minist?rio da Educa??o do Brasil aponta as defici?ncias visuais como um grande desafio aos educadores de crian?as, principalmente no processo de alfabetiza??o. O exame oftalmol?gico tradicional para diagn?stico do estrabismo pode ser realizado induzindo os movimentos oculares atrav?s de instru??es do m?dico ao paciente. Esse procedimento pode ser reproduzido com aux?lio computacional atrav?s da an?lise de imagens capturadas em v?deo. Este trabalho apresenta uma proposta de sistema de teleoftalmologia para auxiliar profissionais da sa?de no diagn?stico a dist?ncia de defici?ncias visuais associadas ? capacidade motora dos olhos, como o estrabismo. Espera-se atrav?s deste trabalho contribuir diretamente para a melhoria dos ?ndices do aprendizado escolar infantil, permitindo melhores condi??es de diagn?stico e, consequentemente, acompanhamento do aluno

O presente texto descreve métodos e apresenta resultados do projeto de pesquisa de mestrado intitulado \"Dois Problemas em Análise de Formas de Estruturas de Ramificação\". Ambos os problemas abordados estão relacionados às sub-áreas da Análise de Formas denominadas Caracterização e Descrição de Formas. O primeiro problema consiste na investigação de um conjunto de características propostas para distingüir, primeiramente, entre estruturas de ramificação de vasos sangüíneos em imagens de retina segmentadas manualmente e automaticamente. A seguir, as mesmas características são aplicadas para discernir entre estruturas de ramificação de vasos sangüíneos em imagens de retina com e sem retinopatia diabética proliferativa (Proliferative Diabetic Retinopathy - PDR). A PDR é uma das patologias associadas à diabetes, que pode culminar na cegueira do indivíduo. Diagnósticos são possíveis por meio de imagens de fundo de olho e, quando efetuados precocemente, viabilizam intervenções oportunas evitando a perda da visão. Neste trabalho, 27 imagens digitais de fundo de olho foram segmentadas por dois processos distintos, isto é, segmentação manual por um especialista e a segmentação automática, mediante a transformada contínua Wavelet - CWT e classificadores estatísticos. Visando à caracterização destas formas, um conjunto de 08 características foi proposto. Este conjunto foi formado por três grupos, a saber: descritores tradicionais geométricos (Área, Perímetro e Circularidade), descritores associados à transformada wavelet ( 2o momento estatístico da distribuição de módulos da CWT, Entropia de Orientação da distribuição de fases da CWT e Curvatura) e um descritor fractal (Dimensão de Correlação - Global e Mediana). Uma Análise Discriminante Linear LDA revelou que as características geométricas tradicionais não detectam o início da retinopatia diabética proliferativa. A maior capacidade discriminante individual foi exibida pela Curvatura, com Área sob a curva ROC de 0.76. Um subconjunto com 6 características apresentou grande capacidade discriminante com Área sob a curva ROC de 0.90. O segundo problema diz respeito à extração de contorno de estruturas de ramificação bidimensionais de neurônios tridimensionais. Este trabalho contribui originalmente com uma solução para este problema, propondo dois algoritmos desenvolvidos para Rastreamento de Ramos e Extração do Contorno Paramétrico de estruturas de ramificação, capazes de transpor regiões críticas formadas por cruzamentos ocasionados pela projeção de estruturas 3D no plano das imagens 2D. Grande parte dos métodos baseados em contorno para análise de formas de estruturas de ramificação de células neuronais não produz representações corretas destas formas, devido à presença de sobreposições entre processos neuronais, levando os algoritmos tradicionais de extração de contorno a ignorar as regiões mais internas destas estruturas, gerando representações incompletas. O sistema proposto neste trabalho foi desenvolvido objetivando a solução do problema de extração de contorno, mesmo na presença de múltiplas sobreposições. Inicialmente, a imagem de entrada é pré-processada, gerando um esqueleto 8-conexo com ramos de um pixel de largura, um conjunto de sementes de sub-árvores dendríticas e um conjunto de regiões críticas (bifurcações e cruzamentos). Para cada sub-árvore, o algoritmo de rastreamento rotula todos os pixels válidos de um ramo, até chegar em uma região crítica, onde o algoritmo decide a direção em que deve continuar o rastreamento. Nosso algoritmo mostrou-se robusto, mesmo quando aplicado a imagens com segmentos paralelos muito próximos. Resultados obtidos com imagens reais (neurônios) são apresentados. / This document describes methods and presents results from the Master of Science\'s research project in computer science entitled \"Two Problems in Shape Analysis of Branching Structures\". Both tackled problems herein are related to Shape Analysis sub-fields, namely Characterization and Description of shapes. The former problem consists of an investigation on a proposed set of features aimed at discriminating, firstly, between blood vessels branching structures manually and automatically segmented. In the sequel, the same features are used to assess their discriminative capability in distinguishing between blood vessels branching structures with and withoud proliferative diabetic retinopathy (PDR). The PDR is a pathology related to diabetes, which may lead to the blindness. Diagnosis is possible through optic fundus image analysis, which may allow timely interventions preventing vision loss. In this work, 27 digital optic fundus images were segmented by two distinct segmentation processes, i.e. manual segmentation carried out by an especialist and automated segmentation, through the CWT (Continuous Wavelet Transform) and statistical classifiers. In order to characterize such a shapes, a set of 8 features has been proposed. The aforementioned set was comprised of three features groups, that is: traditional geometric descriptors (Area, Perimeter and Circularity), wavelet-based descriptors (2nd statistical moment from the CWT Modulus distribution, Orientation Entropy from the CWT Phase distribution and Curvature) and a fractal descriptor (Correlation Dimension - global and median). Linear Discriminant Analysis LDA revelead that the traditional geometric features are not able to detect early proliferative diabetic retinopathy. The largest singular discriminant capability was shown by the Curvature, with area under the ROC curve of 0.76. A subset of 6 features presented a good discriminating power with area under the curve of 0.90. The second problem concerns contour extraction from 2D branching structures of 3D neurons. This work contributes with an original solution for such a problem, proposing two algorithms devised for Branches Tracking and Branching Structures Contour Extraction. The proposed algorithms are able to traverse critical regions implied by the projection of 3D structures onto a 2D image plane. Most of contour-based methods intended to shape analysis of neuronal branching structures fall short of yielding proper shape representations, owing to the presence of overlapings among neuronal processes, causing the traditional algorithms for contour following to ignore the innermost regions, thus generating incomplete representations. The proposed framework system was developed aiming at the solution of the contour extraction problem, even in the presence of multiple overlapings. The input image is pre-processed, so as to obtain an 8-connected skeleton with one-pixel wide branches, a set of seeds of dendritic sub-trees and a set of critical regions (bifurcations, crossings and superpositions). For each sub-tree, the Branches Tracking Algorithm labels all valid pixels of a branch, until reaching a critical region, where the algorithm decides about the direction to go on with the tracking. Our algorithm has shown robustness, even in images plenty of very close parallel segments. Results with real images (neurons) are presented.

Human complex diseases, like Diabetes and Cancer, affect many people worldwide today. Despite existing knowledge, many of these diseases are still not preventable. Complex diseases are known to be caused by a combination of genetic factors, as well as environmental and life style factors. The scope of this investigation covered the genomics of Type 1 Diabetes (T1D). There are 49 human genomic regions that are known to carry markers (disease-associated single nucleotide mutations) for T1D, and these were extensively studied in this research. The aim was to find out in how far this disease may be caused by problems in gene regulation rather than in gene coding. For this, the genetic factors associated with T1D, including the single point mutations and susceptibility regions, were characterised on the basis of their genomic attributes. Furthermore, mutations that occur in binding sites for transcription factors were analysed for change in the conspicuousness of their binding region, caused by allele substitution. This is called SNP (Single nucleotide polymorphism) sensitivity. From this study, it was found that the markers for T1D are mostly non-coding SNPs that occur in introns and non-coding gene transcripts, these are structures known to be involved in gene regulatory activity. It was also discovered that the T1D susceptibility regions contain an abundance of intronic, non-coding transcript and regulatory nucleotides, and that they can be split into three distinct groups on the basis of their structural and functional genomic contents. Finally, using an algorithm designed for this study, thirty-seven SNPs that change the representation of their surrounding region were identified. These regulatory mutations are non-associated T1D-SNPs that are mostly characterised by Cytosine to Thymine (C-T) transition mutations. They were found to be closer in average distance to the disease-associated SNPs than other SNPs in binding sites, and also to occur frequently in the binding motifs for the USF (Upstream stimulatory factor) protein family which is linked to problems in Type 2 diabetes.