DSpace Angular ::Πλοήγηση Διπλωματικές Εργασίες ανά Συγγραφέα "Balas Costas"

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(Technical University of Crete, 2014) Kobotheklas Konstantinos; Κομποθεκλας Κωνσταντινος; Kalaitzakis Kostas; Καλαϊτζακης Κωστας; Balas Costas; Μπαλας Κωστας; Koutroulis Eftychios; Κουτρουλης Ευτυχιος

Emerging issues, modern design trends and future challenges for system design research and design of System-on-a-Chip (SoC), are the focus of semiconductor industry. The architecture of SoC designers consider the overall system performance variably (power, thermal efficiency, production costs, etc. ) in order to present to the market complex and competitive products. With the help of micro-fluidic remarkable is the progress in development of Lab-on-a-Chip (LoC) systems in various fields such as the study of cell biology and disease diagnosis. The micro- biosensors, which are based on LoC systems can incorporate numerous techniques for analysis of biochemical reactions, including analysis based on the image, and techniques for the analysis of genes and proteins of the cell. Medical devices that are already on the market provide significant clinical credibility through immunological tests and Point-of-Care (POC) tests for clinical chemistry. Future applications include complex tests, POC tests with high sensitivity and rather complicated tests, such as nucleic acid tests or the integration of multiple tests in one.

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Data classification and mapping in optical dynamic contrast-enhanced imaging of cervical neoplasia.

(Technical University of Crete, 2014) Chiou Eleni; Χιου Ελενη; Balas Costas; Μπαλας Κωστας; Zervakis Michalis; Ζερβακης Μιχαλης; Lagoudakis Michael; Λαγουδακης Μιχαηλ

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Development of a computer controlled tunable wavelength light source from ultraviolet to infrared

(Πολυτεχνείο Κρήτης, 2013) Rossos Christos; Ρωσσος Χρηστος; Balas Costas; Μπαλας Κωστας; Kalaitzakis Kostas; Καλαϊτζακης Κωστας; Pnevmatikatos Dionysios; Πνευματικατος Διονυσιος

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Development of a self-screening/training mobile platform for eye pathologies

(Technical University of Crete, 2014) Gatzos Evaggelos; Γκατζος Ευαγγελος; Balas Costas; Μπαλας Κωστας; Lagoudakis Michael; Λαγουδακης Μιχαηλ; Mania Aikaterini; Μανια Αικατερινη

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Development of an advanced platform for controlling the imaging parameters of CMOS image sensors.

(Πολυτεχνείο Κρήτης, 2014) Trilyraki Aikaterini; Τριλυρακη Αικατερινη; Balas Costas; Μπαλας Κωστας; Papaefstathiou Ioannis; Παπαευσταθιου Ιωαννης; Bucher Matthias; Bucher Matthias

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Development of an autofocusing system for digital cameras

(Technical University of Crete, 2014) Koutlis Vasileios; Κουτλης Βασιλειος; Balas Costas; Μπαλας Κωστας; Lagoudakis Michael; Λαγουδακης Μιχαηλ; Kalaitzakis Kostas; Καλαϊτζακης Κωστας

Η συγκεκριμένη διπλωματική εργασία μελετάει την ανάπτυξη ενός συστήματος αυτόματης εστίασης, δηλαδή ενός συστήματος που θα εστιάζει πλήρως σε ένα αντικείμενο και θα έχει την βέλτιστη απόκριση. Πριν την ενασχόλησή μας με το θεωρητικό και λογισμικό σκέλος καθορίσαμε τα στοιχεία αυτά που μας είναι απαραίτητα για τη δημιουργία της πειραματικής διάταξης. Όσο αφορά το λογισμικό, για να επιτύχουμε την ανάπτυξη ενός τέτοιου συστήματος εξετάσαμε διαφορετικούς αλγορίθμους και συναρτήσεις. Για να επιτύχουμε τη βέλτιστη εικόνα βασιστήκαμε στην τιμή-εστίασης (focus value), η οποία είναι μία μεταβλητή που υπολογίζει το πόσο καλά εστιασμένη είναι η εικόνα. Για να μετρηθεί αυτή η μεταβλητή χρησιμοποιήσαμε τέσσερις διαφορετικές συναρτήσεις, οι οποίες και αναλύονται με τη χρήση γραφημάτων στα πλαίσια αυτής της διπλωματικής. Αναπόφευκτα, στη μέτρηση αυτής της τιμής εισάγεται σφάλμα, το οποίο ελαχιστοποιούμε με τη χρήση φίλτρων κατά τη διάρκεια λήψης της εικόνας, και μέσω ελέγχου της φωτεινότητας. Η εφαρμογή του συστήματος έγινε κάτω από ποικίλες περιπτώσεις έντασης του φωτός με πολύ ικανοποιητικά αποτελέσματα.

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Development of breast cancer surgery magnetic navigation system

(Technical University of Crete, 2013) Tsoulidis Nikolaos; Τσουλιδης Νικολαος; Balas Costas; Μπαλας Κωστας; Kalaitzakis Kostas; Καλαϊτζακης Κωστας

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Development of underwater vision improving system

(Technical University of Crete, 2015) Petridis Nikolaos; Πετριδης Νικολαος; Balas Costas; Μπαλας Κωστας; Samoladas Vasilis; Σαμολαδας Βασιλης; Stavrakakis Georgios; Σταυρακακης Γεωργιος

Underwater imaging is important for scientiﬁc research and technology, as well as for popular activities. This paper describes a method to overcome limitations in underwater imaging using colour correction and polarizing filters. Scattering and colour absorption are two major problems of distortion for imaging, especially in underwater environment. Scattering is caused by large suspended particles, like fog or turbid water. Colour degradation corresponds to the varying degrees of attenuation encountered by light travelling in the water with different wavelengths, rendering ambient underwater environments dominated by a bluish tone. Our key target was to create a simple and cost efficient method eliminating satisfactorily image blurring and increase colour intensity and visual acuity in natural an artificial lighting source. We demonstrated light as a signal with scattering and backscattering distorting images and also analyzed the function of the human eye contributing to the constraints of vision especially in underwater environment. We researched various different approaches encounter the same topic and made a comparative study and developed an underwater vision system which improves contrast and visual image quality and explained the physical effects of visibility degradation.

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Employing binocular eye tracking for the control of a custom-made immersive multimedia user interface (MUI) in Unity3D

(Technical University of Crete, 2015) Sidorakis Nikolaos; Σιδωρακης Νικολαος; Mania Aikaterini; Μανια Αικατερινη; Koulieris Georgios-Alexandros; Κουλιερης Γεωργιος-Αλεξανδρος; Christodoulakis Stavros; Χριστοδουλακης Σταυρος; Balas Costas; Μπαλας Κωστας

In this thesis, we present an innovative approach to design a gaze controlled Multimedia User Interface for modern, immersive headsets. The wide-spread availability of consumer grade Virtual Reality Head Mounted Displays such as the Oculus RiftTM transformed VR to a commodity available for everyday use. However, Virtual Environments require new paradigms of User Interfaces, since standard 2D interfaces are designed to be viewed from a static vantage point only, e.g. the computer screen. Additionally, traditional input methods such as the keyboard and mouse are hard to manipulate when the user wears a Head Mounted Display. We present a 3D Multimedia User Interface based on eye-tracking and develop six applications which cover commonly operated actions of everyday computing such as mail composing and multimedia viewing. We perform a user study to evaluate our system by acquiring both quantitative and qualitative data. The study indicated that users make less type errors while operating the eye-controlled interface compared to using the standard keyboard during immersive viewing. Subjects stated that they enjoyed the eye-tracking 3D interface more than the keyboard/mouse combination.

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Estimation of gadolinium concentration in MRI using the recalled echo signal

(Technical University of Crete, 2014) Kalaitzakis Georgios; Καλαϊτζακης Γεωργιος; Zervakis Michalis; Ζερβακης Μιχαλης; Balas Costas; Μπαλας Κωστας

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Genetic data analysis for classification of bipolar disorders

(Technical University of Crete, 2015) Leska Valsamo; Λεσκα Βαλσαμω; Zervakis Michalis; Ζερβακης Μιχαλης; Balas Costas; Μπαλας Κωστας; Petrakis Evripidis; Πετρακης Ευριπιδης

In the resent years DNA microarray analysis has become a widely used tool for gene expression profiling and data analysis. This technology can be useful in the classification of complex diseases such as bipolar disorder, providing useful information for its genetic background. Bipolar disorder is a common, heritable mental illness characterized by recurrent episodes of mania and depression that manifests from multiple genetic and environmental factors. There are four basic types of bipolar disorder; bipolar I disorder, dipolar II disorder, Bipolar Disorder Not Otherwise Specified (BP-NOS) and Cyclothymic. The ability to classify dipolar disorders may have a major impact on our understanding of disease pathophysiology and may provide important opportunities to investigate the interaction between genetic and environmental factors involved in pathogenesis. Also this ability may be essential to guide appropriate therapy and determine prognosis for successful treatment. The aim of this diploma thesis is to extract a significant genomic signature for which biological knowledge already exists or discover novel genomic information, which might stand as the motivation for further analysis. Under this genomic signature we classify the bipolar disorders using gene expressions from two different populations. Microarray analysis normally leads to datasets which contain a small number of samples which have a large number of gene expression levels as features. In order to extract useful informative sets of genes that can reduce dimensionality and maximize the performance of classifiers, feature selection algorithms were used. Another aim of this study is to achieve stable performance assessment of feature selection and classification methods. In that manner, the genetic evaluation framework named “Stable Bootstrap Validation” (SBV), introduced be Nick Chlis, is presented. The SBV utilizes bootstrap resampling of the original dataset and an explicit criterion that determines the stability of the observed classification accuracy and the biological interpretation of genes, also called genomic signature. Moreover, methodologies for evaluating the discrimination, consistency and generalization ability of the observed results are also introduced. In this diploma thesis a unified “32 common gene signature” was extracted, which is closely associated with several aspect of bipolar disorders.

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Mobile health screening platform for degenerative neurological disorders

(Technical University of Crete, 2014) Politi Vasiliki; Πολιτη Βασιλικη; Balas Costas; Μπαλας Κωστας; Mania Aikaterini; Μανια Αικατερινη; Chalkiadakis Georgios; Χαλκιαδακης Γεωργιος

The new and dynamic field of mHealth - the use of mobile technology applications for healthcare - could improve the well-being of people around the world. Mobile applications can lower costs and improve the quality of healthcare as well as shift behavior to strengthen prevention, all of which can improve health outcomes over the long term. Technologies of mHealth field are a valuable partner in health care's shift towards a delivery model that is patient-centered and value-based. A broad category of brain diseases is Dementia, which causes long term loss of the ability to think and reason clearly that is severe enough to affect a person's daily functioning. The most common form of Dementia is Alzheimer's disease (75%). Although Alzheimer's disease develops differently for every individual, there are many common symptoms. Early symptoms are often mistakenly thought to be 'age-related' concerns, or manifestations of stress. Neurology cognitive tests used for symptoms recognition to such degenerative disorders are generally applied by paper-and-pencil until now. These kinds of tests implemented until now on PCs have typically unfriendly interface and do not take people's capabilities into consideration. Our aim was to develop a mHealth screening platform that combines various neurological tests that will help the diagnosis of early dementia and Alzheimer disease by easy performed self-testing applications, provided by a friendly GUI. The application is composed of the best 3 tests chosen from the paper-and-pencil standard tests, Clock drawing test (CDT), Mini Cog test (MCT) and Montreal Cognitive Assessment test (MoCA). This thesis is important for being one of the first mobile applications for degenerative neurological disorders self-testing that is compatible for tablets and smart-phones regardless witch operating system is running

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Spectral cube construction from hyper spectral scanning imaging

(Technical University of Crete, 2013) Chantzi Efthymia; Χαντζη Ευθυμια; Balas Costas; Μπαλας Κωστας; Kalaitzakis Kostas; Καλαϊτζακης Κωστας; Bucher Matthias; Bucher Matthias

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Spectral deconvolution and concentration mapping in complex biochemical stains

(Technical University of Crete, 2014) Abatzi Fani; Αμπατζη Φανη; Balas Costas; Μπαλας Κωστας; Epitropou Georgios; Επιτροπου Γεωργιος; Zervakis Michalis; Ζερβακης Μιχαλης; Maravelaki Pagona; Μαραβελακη Παγωνα

Spectral Imaging (SI) combines spectroscopy and imaging, enabling the acquisition of a stack of images at narrow spectral bands comprising the so-called spectral cube. A complete spectrum can be calculated for every image pixel from the multidimensional spatio-spectral space of the cube. This study aims at identifying the concentration of solvents in mixtures of multiple biochemical stains with overlapping spectral signatures. More specifically, a series of experiments has been undertaken via experimental design arrangements (full factorial, face-centered & half factorial) employing both spectrum acquisition by spectrophotometer and spectral imaging acquisition. Furthermore, an extensive number of algorithmic methods, based on Beer Lambert's law generalization, including Classical Least Squares (CLS), Inverse Least Squares (ILS) with forward or backward selection, Principal Components Regression (PCR) and Partial Least Squares (PLS) has been implemented and applied to both simulated and experimental data. It was found that PLS can predict the concentrations in mixtures of two and three solvents with high accuracy on the datasets of spectral images. The combination of SI with concentration prediction algorithms can provide a valuable tool for quantitative assessment of the uptake of biological stains in histochemistry applications.

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Spectral prediction from filtered color CCD cameras

(Technical University of Crete, 2011) Iliou Dimitrios; Ηλιου Δημητριος; Balas Costas; Μπαλας Κωστας; Garofalakis Minos; Γαροφαλακης Μινως; Koutroulis Eftychios; Κουτρουλης Ευτυχιος

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Statistical analysis of low frequency noise in Enclosed Gate MOSFETs

(Πολυτεχνείο Κρήτης, 2016) Nikolaou Aristeidis; Νικολαου Αριστειδης; Bucher Matthias; Bucher Matthias; Balas Costas; Μπαλας Κωστας; Kalaitzakis Kostas; Καλαϊτζακης Κωστας

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Study of low frequency noise in High Voltage MOS transistor

(Πολυτεχνείο Κρήτης, 2014) Fellas Konstantinos; Φελλας Κωνσταντινος; Bucher Matthias; Bucher Matthias; Balas Costas; Μπαλας Κωστας; Koutroulis Eftychios; Κουτρουλης Ευτυχιος

HVMOSFETs find many different applications such as switching applications, input-output operations, voltage conversions, RF amplification etc. The effect of drift region on 1/f noise remained unclear until recently due to the difficulty of performing 1/f noise measurements under high drain voltages, on the order of tens of Volt. This is mainly due to the lack of adequate measurement equipment, which usually restricts low frequency noise to be measured up to just a few Volt, usually generated from batteries. A 1/f noise parameter extraction method for high-voltage (HV-)MOSFETs at 3V drain bias is presented in this thesis. In this region the overall noise is mostly dominated by the noise originating in the channel. The bias dependence of flicker noise, related to transconductance-to-current ratio, allows for an easy means to determine related noise parameters. Though measured data is limited, parameters related to carrier number fluctuation effect may be found. 50 V N and P-channel HV-MOSFETs are investigated for long as well as short channel lengths. The parameter extraction method is applied to a recently established 1/f noise model for HV-MOSFETs, showing a good agreement among model and experimental data.

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Αναγνώριση και κατηγοριοποίηση των κυκλοφορούντων καρκινικών κυττάρων μέσω χρήσης μεταγραφικών δεδομένων

(Πολυτεχνείο Κρήτης, 2015) Kotronia Maria; Κοτρωνια Μαρια; Zervakis Michalis; Ζερβακης Μιχαλης; Garofalakis Minos; Γαροφαλακης Μινως; Balas Costas; Μπαλας Κωστας

Despite recent advances in Microarray technology towards gene expression analysis and extraction of biological significance indices, the successful use of this technology is still elusive for many researchers. This is mainly because there is no standardization yet in methods used for the normalization of systematic noise which occurs during experimental procedures or in methods used for the biological data classification. Also, the analysis of large amount of data produced by such experiments remains a significant challenge. The objective of this diploma thesis was the development of a software platform in Matlab, able of managing and analyzing large amounts of biological data through a single personal computer. The software offers the potential to the user to choose the desired method for data analysis through a variety of normalization and classification algorithms, as well as to develop and integrate custom methods. Data is managed and stored by a specialized database management system. The software platform was tested in a plethora of biological samples with great success. This thesis is intended to serve in biological research as the basis of an innovative and complete software tool for the management and processing of large amounts of biological data in order both to produce reliable and comparable results from different microarray experiments and also to offer potential of choosing between a complete range statistical analysis methods.

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Ανάλυση αδενοκαρκινώματος του πνεύμονα με τη μέθοδο της ψηφιακής επεξεργασίας εικόνας

(Πολυτεχνείο Κρήτης, 2014) Karvelas-Kalogerakis Michail; Καρβελας-Καλογερακης Μιχαηλ; Zervakis Michalis; Ζερβακης Μιχαλης; Balas Costas; Μπαλας Κωστας; Lagoudakis Michael; Λαγουδακης Μιχαηλ

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Ανάπτυξη οπτικού συστήματος προσαρμοστικού ελέγχου κατεργασίας υλικών

(Πολυτεχνείο Κρήτης, 2014) Kouloumentas Panagiotis; Κουλουμεντας Παναγιωτης; Antoniadis Aristomenis; Αντωνιαδης Αριστομενης; Balas Costas; Μπαλας Κωστας; Zervakis Michalis; Ζερβακης Μιχαλης

Σκοπός της εργασίας αυτής είναι η ανάπτυξη οπτικού συστήματος το οποίο θα ελέγχει την ποιότητα του φρεζαρίσματος ενός αντικειμένου. Συγκεκριμένα, το υλικό την στιγμή που θα υπόκειται στην επεξεργασία από τη φρέζα, θα ελέγχεται από το οπτικό σύστημα για την εύρεση των λαθών που έγιναν κατά τη διάρκεια του φρεζαρίσματος. Ο έλεγχος αυτός πρέπει να γίνεται με χρήση καμερών και λέιζερ. Η μεθοδολογία που θα παρουσιαστεί απαιτεί το λιγότερο δύο κάμερες και μια συσκευή παραγωγής γραμμής λέιζερ, η οποία θα προσπίπτει πάνω στο τμήμα του αντικειμένου το οποίο δέχεται την επεξεργασία της φρέζας. Εννοείται ότι σκοπός της μεθοδολογίας είναι η απόκτηση της γνώσης για τις ακριβείς διαστάσεις του κάθε σημείου του αντικειμένου, το οποίο σκανάρεται από το σύστημα των καμερών και της γραμμής λέιζερ. Επομένως κάνοντας μια αφαίρεση, θα μπορούσε να ειπωθεί ότι βαθύτερος σκοπός της εργασίας είναι η υλοποίηση ενός τρισδιάστατου σαρωτή, αντικειμένων με χρήση δύο ή και περισσότερων αισθητήρων, οι οποίοι λαμβάνουν στερεοσκοπικές εικόνες από το λέιζερ, και μετά από την επεξεργασία των εικόνων επιτυγχάνεται η τρισδιάστατη ανακατασκευή του αντικειμένου. Αξίζει να τονιστεί, ότι η διαφορά του τρισδιάστατου αυτού σαρωτή σε σχέση με αυτούς του εμπορίου είναι ότι ο πρώτος είναι πιο οικονομικός καθώς χρησιμοποιούνται δύο απλές CCD κάμερες και ένας προβολέας γραμμής λέιζερ του εμπορίου, από αυτούς που χρησιμοποιούνται για το αλφάδιασμα κατασκευών.

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