cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Αντιμετώπιση του πρώτου επεισοδίου πρωτοπαθούς αυτόματου πνευμοθώρακα σε ενήλικες: Σωλήνας θωρακικής παροχέτευσης ή αναρρόφηση αέρα; Συστηματική ανασκόπηση και μετα-ανάλυση
Creators: name: Καπούλας, Σπυρίδων Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: αυτόματος πνευμοθώρακας
αναρρόφηση
μετα-ανάλυση
spontaneous pneumothorax
aspiration
meta-analysis

description: Στόχοι: Ο καταλληλότερος τρόπος αντιμετώπισης ενός επεισοδίου πρωτοπαθούς αυτόματου πνευμοθώρακα παραμένει εδώ και πολλά χρόνια ζήτημα αμφιλεγόμενο με διαφορετικές κατευθυντήριες οδηγίες μεταξύ των διαφόρων κρατών. Η παρούσα ανασκόπηση συγκρίνει την απλή αναρρόφηση αέρα και την τοποθέτηση σωλήνα θωρακικής παροχέτευσης με βάση τυχαιοποιημένες μελέτες που δημοσιεύθηκαν μέχρι τον Ιούνιο του 2015. Μέθοδοι: Συμπεριλήφθηκαν οι βάσεις δεδομένων MEDLINE, EMBASE και COCHRANE CENTRAL ενώ πραγματοποιήθηκε αναζήτηση σε μητρώα κλινικών δοκιμών όπως και στις βιβλιογραφικές αναφορές των άρθρων που συμπεριλήφθηκαν στην συστηματική ανασκόπηση. Η αξιοπιστία των μελετών αξιολογήθηκε με το Cochrane Risk of Bias Assessment tool. Αποτελέσματα: H αναρρόφηση δε διαφέρει στα ποσοστά άμεσης επιτυχίας (RR=0,89, CI 95%: 0,75-1,07) και υποτροπών (RR=0,92 , CI 95%: 0,58-1,48) από την τοποθέτηση σωλήνα θωρακικής παροχέτευσης, χαρακτηρίζεται όμως από συντομότερη νοσηλεία (WMD = - 1,68 , CI 95% : -2,39 έως -0,97). Συμπεράσματα: Η απλή αναρρόφηση του αέρα είναι εξίσου αποτελεσματική με την τοποθέτηση σωλήνα θωρακικής παροχέτευσης για την αντιμετώπιση του πρώτου επεισοδίου πρωτοπαθούς αυτόματου πνευμοθώρακα σε ενήλικες. Ίσως όμως λόγω της συντομότερης νοσηλείας να αποτελεί την μέθοδο εκλογής για το πρόβλημα αυτό. Λέξεις κλειδιά : αυτόματος πνευμοθώρακας, αναρρόφηση, θωρακοκέντηση, σωλήνας θωρακικής παροχέτευσης, μετα-ανάλυση
description: Aim: The best way to treat an episode of primary spontaneous pneumothorax remains controversial and several different guidelines have been published worldwide over the years. The present review compares the simple aspiration of air with intercostal chest tube insertion based on randomized controlled trials published until June 2015. Methods: Medical databases MEDLINE,EMBASE and COCHRANE CENTRAL were searched to identify eligible trials. We also searched trial registries and the reference lists of the included studies. The Cochrane risk of bias assessment tool was used to explore study quality. Results: There was no difference between simple aspiration and intercostal chest tube drainage in terms of immediate success (Risk Ratio,RR=0,89 , CI 95%: 0,75-1,07) or recurrence rate in the first year (RR=0,92 , CI 95%: 0,58-1,48). However, aspiration was associated with shorter hospital stay (Weighted Mean Difference,WMD = - 1,68 , CI 95% : -2,39 to -0,97). Conclusions: Based on current evidence air aspiration is as effective as chest tube insertion for the treatment of the first episode of primary spontaneous pneumothorax in adults. However, given the need for shorter hospital stay, aspiration should probably be the treatment of choice for these patients. Key-words: spontaneous pneumothorax, aspiration, thoracocentesis, chest tube, meta-analysis.
A nonaspherical cell-like 2-dimensional simply connected continuum and related constructions
Creators: name: Eda, Katsuya
name: Karimov, Umed H.
name: Repovš, Dušan
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Topology (math.GN)
subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 54B15; 55N10; 55Q52

description: We prove the existence of a 2-dimensional nonaspherical simply connected cell-like Peano continuum (the space itself was constructed in one of our earlier papers). We also indicate some relations between this space and the well-known Griffiths' space from the 1950's.
An Automatic System to Discriminate Malignant from Benign Massive Lesions on Mammograms
Creators: name: Retico, A.
name: Delogu, P.
name: Fantacci, M. E.
name: Kasae, P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: Mammography is widely recognized as the most reliable technique for early detection of breast cancers. Automated or semi-automated computerized classification schemes can be very useful in assisting radiologists with a second opinion about the visual diagnosis of breast lesions, thus leading to a reduction in the number of unnecessary biopsies. We present a computer-aided diagnosis (CADi) system for the characterization of massive lesions in mammograms, whose aim is to distinguish malignant from benign masses. The CADi system we realized is based on a three-stage algorithm: a) a segmentation technique extracts the contours of the massive lesion from the image; b) sixteen features based on size and shape of the lesion are computed; c) a neural classifier merges the features into an estimated likelihood of malignancy. A dataset of 226 massive lesions (109 malignant and 117 benign) has been used in this study. The system performances have been evaluated terms of the receiver-operating characteristic (ROC) analysis, obtaining A_z = 0.80+-0.04 as the estimated area under the ROC curve.
description: 6 pages, 3 figures; Proceedings of the ITBS 2005, 3rd International Conference on Imaging Technologies in Biomedical Sciences, 25-28 September 2005, Milos Island, Greece
On the first $δ$ Sct--roAp hybrid pulsator and the stability of p and g modes in chemically peculiar A/F stars
Creators: name: Murphy, Simon J.
name: Saio, Hideyuki
name: Takada-Hidai, Masahide
name: Kurtz, Donald W.
name: Shibahashi, Hiromoto
name: Takata, Masao
name: Hey, Daniel R.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Strong magnetic fields in chemically peculiar A-type (Ap) stars typically suppress low-overtone pressure modes (p modes) but allow high-overtone p modes to be driven. KIC 11296437 is the first star to show both. We obtained and analysed a Subaru spectrum, from which we show that KIC 11296437 has abundances similar to other magnetic Ap stars, and we estimate a mean magnetic field modulus of $2.8\pm0.5$ kG. The same spectrum rules out a double-lined spectroscopic binary, and we use other techniques to rule out binarity over a wide parameter space, so the two pulsation types originate in one $δ$ Sct--roAp hybrid pulsator. We construct stellar models depleted in helium and demonstrate that helium settling is second to magnetic damping in suppressing low-overtone p modes in Ap stars. We compute the magnetic damping effect for selected p and g modes, and find that modes with frequencies similar to the fundamental mode are driven for polar field strengths $\lesssim4$ kG, while other low-overtone p modes are driven for polar field strengths up to $\sim$1.5 kG. We find that the high-order g modes commonly observed in $γ$ Dor stars are heavily damped by polar fields stronger than 1--4 kG, with the damping being stronger for higher radial orders. We therefore explain the observation that no magnetic Ap stars have been observed as $γ$ Dor stars. We use our helium-depleted models to calculate the $δ$ Sct instability strip for metallic-lined A (Am) stars, and find that driving from a Rosseland mean opacity bump at $\sim$$5\times10^4$ K caused by the discontinuous H-ionization edge in bound-free opacity explains the observation of $δ$ Sct pulsations in Am stars.
description: Accepted for publication in MNRAS
Spontaneous Creation of the Brane World and Direction of the Time Arrow
Creators: name: Gorsky, A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this note we consider the spontaneous creation of the brane world in five-dimensional space with nondynamical external four-form field via spherically asymmetric bounce solution. We argue that spherically asymmetric bounce suggests several inequivalent directions of the time arrow upon the analytic continuation to the space-time with Lorentzian signature. It it shown that S-branes in the imaginary time emerge naturally upon the particular continuation.
description: 12 pages, 3 figures
Quantum bicritical point and phase separation in a frustrated Heisenberg ladder
Creators: name: Almeida, D. S.
name: Montenegro-Filho, R. R.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We use the density matrix renormalization group (DMRG) and a hard-core boson map to investigate the quantum phase transitions present in the phase diagram of the frustrated Heisenberg ladder in a magnetic field. The quantum bicritical point is observed at the end of a first-order transition line, which is at the meeting of the two second-order transition lines that bound the fully polarized plateau. The characterization of the bicritical point was made using a hard-core boson mapping of the low-energy excitations from the fully polarized phase and through DMRG by studying the probability density of finding the rung spins in a singlet or a triplet state with zero spin component along the magnetic field. In particular, we give conditions for the exchange couplings for the presence of the first-order transition line and the bicritical point in the phase diagram. Moreover, we unveil the phase-separated states for magnetization values inside the magnetization jump and, in particular, the dependence on the system size of the energy curve as a function of magnetization. Finite-size scaling analysis of the transverse spin correlation functions has been used to estimate the critical points of the Kosterlitz-Thouless transitions from the fractional magnetization plateau $m=1/2$ to the respective gapless Luttinger liquid phases for some sets of parameters.
description: 14 pages, 14 figures
Η νομοθετική πολιτική για την εκπαίδευση της μουλσουμανικής μειονότητας της Δυτικής Θράκης 1923-1940
Creators: name: Τσιούμης, Κωστής
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1998

description: Legislation Policy for the Education of Muslim Minority in Western Thrace in the years 1923-1940. This study aims to approach and interpret the intentions of the Greek governments as regards the education of the Muslim Minority in Western Thrace during the mid-war years as they made know through specific legislation. First we examine the legislation that had been in force until the time the Lausanne Peace Treaty was signed. Then we proceed to analyze the post - 1923 laws, directly or indirectly referring to the education of the Muslim Minority in Western Thrace. Besides we indicate archival material concerning the implementation of those legislative regulations, which ascertain the laxity of the educational provisions for the Muslim Minority.
description: Παιδαγωγική Επιθεώρηση, Vol. 27 (1998)
A note on derived McKay correspondence
Creators: name: Chen, Jiun-Cheng
name: Tseng, Hsian-Hua
Publisher: name: arXiv
Year: 2006
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: We obtain a global version and a twisted version (in the sense of \cite{bp05}) of the main theorem of \cite{bkr}.
Advanced noncoherent receivers for mobile fading channels
Creators: name: Bouras, Dimitrios P.
Publisher: name: University of British Columbia
Year: 2009

description: The purpose of this thesis, is to derive and evaluate the performance of noncoherent, maximum likelihood receivers with improved performance, for trellis coded PSK and QAM type signals, transmitted over Rician, correlated, fast, frequency non-selective and frequency selective fading channels, with and without diversity. First we derive the optimal, in the maximum likelihood detection sense, receiver structure for frequency non-selective Rician fading channels, employing diversity reception. In order to reduce the complexity of the optimal receiver, we propose and evaluate the performance of suboptimal receiver structures, which show significant performance improvements as compared to conventional techniques. Investigation of the effects on performance of the proposed algorithms, due to imperfect statistical knowledge of the fading channel typical for a real life environment, demonstrates very small sensitivity even to large errors in estimates of channel parameters. Complementing our work in frequency non-selective fading, we derive the optimal, in the maximum likelihood detection sense, receiver, for the correlated, fast, frequency selective Rician fading channel. In the interest of system simplicity, we propose and evaluate reduced complexity versions of the decoding algorithms. The impact of simplifying assumptions in the theoretical derivation, as well as the receiver sensitivity to non ideal channel knowledge, is investigated. The results show significant performance improvements over the fastest known channel equalization technique, accompanied by small sensitivity to imperfections. Last, we derive analytical performance bounds for simplified versions of the optimal diversity receiver, for frequency non-selective, Rician fading channels. The tightness and accuracy of the bounds is verified, through the excellent agreement between computer simulation results, and bound calculation. Performance evaluation demonstrates significant improvements, approaching the effectiveness of coherent detection in AWGN, even with a relatively small diversity order, for Rician, as well as shadowed EHF fading channels.
Time delay in the strong field limit for null and timelike signals and its simple interpretation
Creators: name: Liu, Haotian
name: Jia, Junji
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Gravitational lensing can happen not only for null signal but also timelike signals such as neutrinos and massive gravitational waves in some theories beyond GR. In this work we study the time delay between different relativistic images formed by signals with arbitrary asymptotic velocity $v$ in general static and spherically symmetric spacetimes. A perturbative method is used to calculate the total travel time in the strong field limit, which is found to be in quasi-series of the small parameter $a=1-b_c/b$ where $b$ is the impact parameter and $b_c$ is its critical value. The coefficients of the series are completely fixed by the behaviour of the metric functions near the particle sphere $r_c$ and only the first term of the series contains a weak logarithmic divergence. The time delay $Δt_{n,m}$ to the leading non-trivial order was shown to equal the particle sphere circumference divided by the local signal velocity and multiplied by the winding number and the redshift factor. By assuming the Sgr A* supermassive black hole is a Hayward one, we were able to validate the quasi-series form of the total time, and reveal the effects of the spacetime parameter $l$, the signal velocity $v$ and the source/detector coordinate difference $Δϕ_{sd}$ on the time delay. It is found that as $l$ increase from 0 to its critical value $l_c$, both $r_c$ and $Δt_{n,m}$ decrease. The variation of $Δt_{n+1,n}$ for $l$ from 0 to $l_c$ can be as large as $7.2\times 10^1$ [s], whose measurement then can be used to constrain the value of $l$. While for ultra-relativistic neutrino or gravitational wave, the variation of $Δt_{n,m}$ is too small to be resolved. The dependence of $Δt_{n,-n}$ on $Δϕ_{sd}$ shows that to temporally resolve the two sequences of images from opposite sides of the lens, $|Δϕ_{sd}-π|$ has to be larger than certain value.
description: 24 pages, 3 figures
Intertwining vertex operators and certain representations of sl(n)^
Creators: name: Calinescu, Corina
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Algebra (math.QA)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 17B69, 17B65

description: We study the principal subspaces, introduced by B. Feigin and A. Stoyanovsky, of the level 1 standard modules for $\hat{\goth{sl}(l+1)}$ with $l \geq 2$. In this paper we construct exact sequences which give us a complete set of recursions that characterize the graded dimensions of the principal subspaces of these representations. This problem can be viewed as a continuation of a new program to obtain Rogers-Ramanujan-type recursions, which was initiated by S. Capparelli, J. Lepowsky and A. Milas. In order to prove the exactness of the sequences we use intertwining vertex operators and we supply a proof of the completeness of a list of relations for the principal subspaces. By solving these recursions we recover the graded dimensions of the principal subspaces, previously obtained by G. Georgiev using a different method.
description: 38 pages; v2: an error corrected, other minor changes
Οι μηχανισμοί επιλογής στο ελληνικό εκπαιδευτικό σύστημα από το 1834 έως το 1985 μια ιστορική - συγκριτική προσέγγιση
Creators: name: Σιπητάνου, Αθηνά
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1998

description: Les mécanismes de sélection du système éducatif grec (1834-1985) Cette étude vise aussi bien à donner un aperçu sociologique et une taxinomie des mécanismes de sélection du système éducatif, qu' â faire une exploration et une exploita-, on des lois décrets et réglementations en matière d’éducation en Grèce pendant les 150 dernières années et à les examiner dans le cadre historique et social où ils se situent. Elle se centre plus précisément aux mécanismes directs de sélection qui étaient en vigueur à tous les niveaux et sur tous les types d’écoles depuis 1834 jusqu' a 1985. Par mécanismes directs de sélection on entend les processus organisés qui contrôlent le pas¬sage des élèves d' une classe a 1' autre, d' un niveau scolaire a l' autre et d' un type d' éco¬le à un autre. En même temps que le développement historique de I' institution des examens, on a de sélection a subis a l intérieur de chaque réforme éducative et on a tenté de faire le lien entre ces mécanismes de sélection et le cadre historique et social qui les a imposés. Nos sources de travail proviennent du matériel original des textes officiels (lois, dé¬crets, circulaires, réglementations, décisions Ministérielles, rapports d’accompagnement des réformes éducatives, actes des commissions d’éducation, des réunions du Haut Con¬seil de I' Éducation et des rencontres sur 1' éducation), ainsi que d une riche bibliographie.
description: Παιδαγωγική Επιθεώρηση, Vol. 27 (1998)
An analysis of three model-based estimation methods for diesel engine condition monitoring
Creators: name: Constantinescu, Raluca F.
Publisher: name: University of British Columbia
Year: 2009

description: In the context of engine fault detection and isolation, we focus on three main aspects: engine modeling and validation, engine parameter identification, and cylinder pressure waveform reconstruction. The problem of diesel engine modeling is solved using Euler's equation, under the assumption that the crankshaft is perfectly rigid. The model inputs are represented by the cylinder pressures and the output is the flywheel angular velocity fluctuation. Simulation results obtained with MATLAB show a root mean square (RMS) error of 0.0891 rad/sec between the estimated and the actual crankshaft angular velocity fluctuation for the normal operating condition. The elimination of a strong sinusoidal trend for the faulty condition results in a RMS error range of 0.0973 rad/sec to 0.1836 rad/sec. The identification methods involved the off-line standard least-squares technique, the recursive gradient estimator and the on-line least-squares estimators with exponential forgetting. The parameters of interest are engine inertia, and torque fluctuation. The RMS velocity error for the normal operation has a value of 0.0559 rad/sec, which represents approximately 30% improvement over the initial result, before identification. The issue of cylinder pressure waveform reconstruction is addressed. The inverse dynamics are solved by redefining the system input as the torque due to gas pressure. The cylinder pressure waveform is approximated by an impulse-like periodic function. We considered the problem of fault detection and isolation. The procedure uses 6 pressure templates. The estimated pressure variations are obtained using a standard least-squares technique. An under-fueling fault in the i-th firing cylinder can be determined exactly by the minimum value of the estimated pressure variation. Using the pressure correction we are able to improve the estimation of the gas pressure torque. The RMS torque error for the normal operation reduces to 99.24 Nm. The case of an under-fueling fault is characterized by a reduced RMS torque error range of 85.7 Nm to 198.1 Nm. The pressure waveform reconstruction is characterized by a RMS pressure error range of 0.155 MPa to 0.277 MPa for the normal operating condition. For each of the six under-fueling faults, the pressure waveform corresponding to the faulty cylinder is reconstructed. The RMS error range is of 0.155 MPa to 0.386 MPa.
Η Εθνοτική Επιχειρηματικότητα στις Ηνωμένες Πολιτείες της Αμερικής
Creators: name: Αθανασιάδης-Χατζηθεοδωρίδης, Αθανάσιος Δημητρίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Εθνοτική Επιχειρηματικότητα
Μειονότητες
ΗΠΑ
Ethnic Entrepreneurship
Minorities
USA

description: Η εργασία επιδιώκει να ερευνήσει τις αιτιατές σχέσεις μεταξύ του βαθμού αποδοχής διαφόρων εθνικών ομάδων από τις κοινωνίες και της επιχειρηματικότητας που παρουσιάζουν οι ομάδες αυτές, στις Ηνωμένες Πολιτείες της Αμερικής. Ο βαθμός αποδοχής μιας κοινωνίας σε σχέση με τον αριθμό των εθνοτικών επιχειρηματιών είναι ένα θέμα που έχει απασχολήσει εκτενώς την βιβλιογραφία και έχει λάβει διάφορες μορφές. Στην παρούσα εργασία, η μορφή η οποία λαμβάνει είναι η αντίθετη της συντηρητικότητας της υπό μελέτης κοινωνίας, εκφραζόμενη μέσα από το αποτέλεσμα των προεδρικών εκλογών σε αυτήν. Εκτός αυτού, λαμβάνονται υπ’ όψιν και άλλοι παράγοντες, όπως το ποσοστό αναλφαβητισμού, η ανεργία και το εθνικό ακαθάριστο προϊόν. Η μέθοδος ανάλυσης είναι αυτή των ελαχίστων τετραγώνων (OLS) με την βοήθεια του οικονομετρικού προγράμματος Microfit 5.0, ενώ τα δεδομένα που χρησιμοποιήθηκαν προέρχονται από το US Census Bureau και αφορούν την χρονική περίοδο του 2004.
description: This paper seeks to investigate the causal relationship between the degree of acceptance of different ethnic groups by societies and entrepreneurship presented by these groups in the United States of America. The acceptability of a society in relation to the number of ethnic entrepreneurs is a topic that literature has been extensively deal with and has taken various forms in it. In this paper, the form that takes is the opposite of conservatism in the community, expressed through the outcome of the presidential elections there. Other factors such as illiteracy, unemployment and the gross national product are taking into account. The analysis method is least squares (OLS) with the help of econometric Microfit program 5.0, while the data used come from the US Census Bureau and concern the period of 2004.
The Rapid ASKAP Continuum Survey I: Design and First Results
Creators: name: McConnell, D.
name: Hale, C. L.
name: Lenc, E.
name: Banfield, J. K.
name: Heald, George
name: Hotan, A. W.
name: Leung, James K.
name: Moss, Vanessa A.
name: Murphy, Tara
name: O'Brien, Andrew
name: Pritchard, Joshua
name: Raja, Wasim
name: Sadler, Elaine M.
name: Stewart, Adam
name: Thomson, Alec J. M.
name: Whiting, M.
name: Allison, James R.
name: Amy, S. W.
name: Anderson, C.
name: Ball, Lewis
name: Bannister, Keith W.
name: Bell, Martin
name: Bock, Douglas C. -J.
name: Bolton, Russ
name: Bunton, J. D.
name: Chippendale, A. P.
name: Collier, J. D.
name: Cooray, F. R.
name: Cornwell, T. J.
name: Diamond, P. J.
name: Edwards, P. G.
name: Gupta, N.
name: Hayman, Douglas B.
name: Heywood, Ian
name: Jackson, C. A.
name: Koribalski, Bärbel S.
name: Lee-Waddell, Karen
name: McClure-Griffiths, N. M.
name: Ng, Alan
name: Norris, Ray P.
name: Phillips, Chris
name: Reynolds, John E.
name: Roxby, Daniel N.
name: Schinckel, Antony E. T.
name: Shields, Matt
name: Tremblay, Chenoa
name: Tzioumis, A.
name: Voronkov, M. A.
name: Westmeier, Tobias
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The Rapid ASKAP Continuum Survey (RACS) is the first large-area survey to be conducted with the full 36-antenna Australian Square Kilometre Array Pathfinder (ASKAP) telescope. RACS will provide a shallow model of the ASKAP sky that will aid the calibration of future deep ASKAP surveys. RACS will cover the whole sky visible from the ASKAP site in Western Australia, and will cover the full ASKAP band of $700-1800$ MHz. The RACS images are generally deeper than the existing NRAO VLA Sky Survey (NVSS) and Sydney University Molonglo Sky Survey (SUMSS) radio surveys and have better spatial resolution. All RACS survey products will be public, including radio images (with $\sim 15$ arcsecond resolution) and catalogues of about three million source components with spectral index and polarisation information. In this paper, we present a description of the RACS survey and the first data release of 903 images covering the sky south of declination $+41^\circ$ made over a 288 MHz band centred at 887.5 MHz.
description: 24 pages, 17 figures, 4 tables. For associated data see https://data.csiro.au/collections/domain/casdaObservation/results/PRAS110%20-%20The%20Rapid%20ASKAP%20Continuum
Bilayer Vanadium Dioxide Thin Film with Elevated Transition Temperatures and High Resistance Switching
Creators: name: Dutta, Achintya
name: P, Ashok
name: Verma, Amit
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Despite widespread interest in the phase-change applications of vanadium dioxide (VO$_2$), the fabrication of high-quality VO$_2$ thin films with elevated transition temperatures (TIMT) and high Insulator-Metal-Transition resistance switching still remains a challenge. This study introduces a two-step atmospheric oxidation approach to fabricate bilayer VO$_{2-x}$/VO$_2$ films on a c-plane sapphire substrate. To quantify the impact of the VO$_2$ buffer layer, a single-layer VO$_2$ film of the same thickness was also fabricated. The bilayer VO$_{2-x}$/VO$_2$ films wherein the top VO$_{2-x}$ film was under-oxidized demonstrated an elevation in TIMT reaching ~97 $^\circ$C, one of the highest reported to date for VO$_2$ films and is achieved in a doping-free manner. Our results also reveal a one-order increase in resistance switching, with the optimum bilayer VO$_2$/VO$_2$ film exhibiting ~3.6 orders of switching from 25 $^\circ$C to 110 $^\circ$C, compared to the optimum single-layer VO$_2$ reference film. This is accompanied by a one-order decrease in the on-state resistance in its metallic phase. The elevation in TIMT, coupled with increased strain extracted from the XRD characterization of the bilayer film, suggests the possibility of compressive strain along the c-axis. These VO$_{2-x}$/VO$_2$ films also demonstrate a significant change in the slope of their resistance vs temperature curves contrary to the conventional smooth transition. This feature was ascribed to the rutile/monoclinic quasi-heterostructure formed due to the top VO$_{2-x}$ film having a reduced TIMT. Our findings carry significant implications for both the lucid fabrication of VO$_2$ thin film devices as well as the study of phase transitions in correlated oxides.
Electrochemical transport in Dirac nodal-line semimetals
Creators: name: Flores-Calderón, R.
name: Medel, Leonardo
name: Martín-Ruiz, A.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Nodal-line semimetals are topological phases where the conduction and the valence bands cross each other along one-dimensional lines in the Brillouin zone, which are symmetry protected by either spatial symmetries or time-reversal symmetry. In particular, nodal lines protected by the combined $\mathcal{PT}$ symmetry exhibits the parity anomaly of 2D Dirac fermions. In this Letter, we study the electrochemical transport in a $\mathcal{PT}$-symmetric Dirac nodal line semimetals by using the semiclassical Boltzmann equation approach. We derive a general formula for the topological current that includes both the Berry curvature and the orbital magnetic moment. We first evaluate the electrochemical current by introducing a small $\mathcal{PT}$-breaking mass term (which could be induced by inversion-breaking uniaxial strain, pressure, or an external electric field) and apply it to the hexagonal pnictide CaAgP. The electrochemical current vanishes in the zero-mass limit. Introducing a tilting term that does not spoil $\mathcal{PT}$ symmetry that protects the nodal ring, we obtain a finite electrochemical current in the zero-mass limit, which can be regarded as a direct consequence of the parity anomaly. We show that the parity anomaly induced electrochemical transport is also present at nonzero temperatures.
Η εξέλιξη της Παιδαγωγικής Επιστήμης και ο ρόλος της στην εκπαίδευση των Ελλήνων εκπαιδευτικών
Creators: name: Μπίκος, Κωνσταντίνος
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1998

description: Aiming at a critical assessment of the role of the Pedagogical Science in the Greek educational actuality, retrospection in its evaluation course is being attempted. The main interest focuses in parallel at two levels: on the one hand at the impacts which the Greek Pedagogy received, as well as the mainstreams which were formed at each phase of development. Regarding the impacts, we have to point out first of all the domination of: German influences for several decades. Further to this, a gradual emancipation of the Greek Pedagogy from the German thought is being ascertained and we realize the appearance of elements not only from the rest European but also from the American Since it is an applied science, a critical assessment of its presence and its intervention ability in the Greek school reality and the formation of the various educational policies is being attempted. Both these points of view which were previously mentioned are being looked into through the role which the Greek Pedagogy played in the education of the Greek tutors at each phase of its development.
description: Παιδαγωγική Επιθεώρηση, Vol. 27 (1998)
Identification of photons in double beta-decay experiments using segmented germanium detectors - studies with a GERDA Phase II prototype detector
Creators: name: Abt, I.
name: Caldwell, A.
name: Kröninger, K.
name: Liu, J.
name: Liu, X.
name: Majorovits, B.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The sensitivity of experiments searching for neutrinoless double beta-decay of germanium was so far limited by the background induced by external gamma-radiation. Segmented germanium detectors can be used to identify photons and thus reduce this background component. The GERmanium Detector Array, GERDA, will use highly segmented germanium detectors in its second phase. The identification of photonic events is investigated using a prototype detector. The results are compared with Monte Carlo data.
description: 20 pages, 7 figures, to be submitted to NIM-A
ClST: A Convolutional Transformer Framework for Automatic Modulation Recognition by Knowledge Distillation
Creators: name: Hou, Dongbin
name: Li, Lixin
name: Lin, Wensheng
name: Liang, Junli
name: Han, Zhu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Signal Processing (eess.SP)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: With the rapid development of deep learning (DL) in recent years, automatic modulation recognition (AMR) with DL has achieved high accuracy. However, insufficient training signal data in complicated channel environments and large-scale DL models are critical factors that make DL methods difficult to deploy in practice. Aiming to these problems, we propose a novel neural network named convolution-linked signal transformer (ClST) and a novel knowledge distillation method named signal knowledge distillation (SKD). The ClST is accomplished through three primary modifications: a hierarchy of transformer containing convolution, a novel attention mechanism named parallel spatial-channel attention (PSCA) mechanism and a novel convolutional transformer block named convolution-transformer projection (CTP) to leverage a convolutional projection. The SKD is a knowledge distillation method to effectively reduce the parameters and complexity of neural networks. We train two lightweight neural networks using the SKD algorithm, KD-CNN and KD-MobileNet, to meet the demand that neural networks can be used on miniaturized devices. The simulation results demonstrate that the ClST outperforms advanced neural networks on all datasets. Moreover, both KD-CNN and KD-MobileNet obtain higher recognition accuracy with less network complexity, which is very beneficial for the deployment of AMR on miniaturized communication devices.
Neutral Fitness Landscape in the Cellular Automata Majority Problem
Creators: name: Verel, Sébastien
name: Collard, Philippe
name: Tomassini, Marco
name: Vanneschi, Leonardo
Publisher: name: arXiv
Year: 2008
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences

description: We study in detail the fitness landscape of a difficult cellular automata computational task: the majority problem. Our results show why this problem landscape is so hard to search, and we quantify the large degree of neutrality found in various ways. We show that a particular subspace of the solution space, called the "Olympus", is where good solutions concentrate, and give measures to quantitatively characterize this subspace.
Περιβαλλοντική αγωγή και περιβαλλοντική συμπεριφορά: μία κριτική συνθετική προσέγγιση μέσω βιβλιογραφικής διερεύνησης
Creators: name: Κρίβας, Σπύρος
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1998

description: Ausgehend vοn der These, da das umweltgerechte Verhalten ein wichtiges Ziel der Umwelterziehung ist, befaßt sich die vorliegende Arbeit mit der Erforchung von Komponenten dieses Verhallens. Dies wird anhand von Sekundaranalyse vorhandenen empirischen und anderen Materials versucht. Weil das Umweltbewußtsein einer bedeutenden Pradiktor des Umweltverhaltens darstellt, legt diese Arbeit Gewicht auf seinen Konstruktvariablen. Gema der Ergebnisse unseres Forschungsanliegens sind Umweltwissen, Umweltbewußtsein und Umwelteinstellungen notwendige aber auch unzureichende Bedingungsfaktoren zur Realisirung eines umweltgereichien Verhatens Dafür intervenieren auch individuelle und auiperindmduelle Faktoren.
description: Παιδαγωγική Επιθεώρηση, Vol. 27 (1998)
Device Sampling for Heterogeneous Federated Learning: Theory, Algorithms, and Implementation
Creators: name: Wang, Su
name: Lee, Mengyuan
name: Hosseinalipour, Seyyedali
name: Morabito, Roberto
name: Chiang, Mung
name: Brinton, Christopher G.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: The conventional federated learning (FedL) architecture distributes machine learning (ML) across worker devices by having them train local models that are periodically aggregated by a server. FedL ignores two important characteristics of contemporary wireless networks, however: (i) the network may contain heterogeneous communication/computation resources, while (ii) there may be significant overlaps in devices' local data distributions. In this work, we develop a novel optimization methodology that jointly accounts for these factors via intelligent device sampling complemented by device-to-device (D2D) offloading. Our optimization aims to select the best combination of sampled nodes and data offloading configuration to maximize FedL training accuracy subject to realistic constraints on the network topology and device capabilities. Theoretical analysis of the D2D offloading subproblem leads to new FedL convergence bounds and an efficient sequential convex optimizer. Using this result, we develop a sampling methodology based on graph convolutional networks (GCNs) which learns the relationship between network attributes, sampled nodes, and resulting offloading that maximizes FedL accuracy. Through evaluation on real-world datasets and network measurements from our IoT testbed, we find that our methodology while sampling less than 5% of all devices outperforms conventional FedL substantially both in terms of trained model accuracy and required resource utilization.
description: This paper is accepted for publication in the proceedings of 2021 IEEE International Conference on Computer Communications (INFOCOM)
A Deontic Logic Analysis of Autonomous Systems' Safety
Creators: name: Shea-Blymyer, Colin
name: Abbas, Houssam
Publisher: name: arXiv
Year: 2020
Subjects: subject: Logic in Computer Science (cs.LO)
subject: Systems and Control (eess.SY)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: We consider the pressing question of how to model, verify, and ensure that autonomous systems meet certain \textit{obligations} (like the obligation to respect traffic laws), and refrain from impermissible behavior (like recklessly changing lanes). Temporal logics are heavily used in autonomous system design; however, as we illustrate here, temporal (alethic) logics alone are inappropriate for reasoning about obligations of autonomous systems. This paper proposes the use of Dominance Act Utilitarianism (DAU), a deontic logic of agency, to encode and reason about obligations of autonomous systems. We use DAU to analyze Intel's Responsibility-Sensitive Safety (RSS) proposal as a real-world case study. We demonstrate that DAU can express well-posed RSS rules, formally derive undesirable consequences of these rules, illustrate how DAU could help design systems that have specific obligations, and how to model-check DAU obligations.
description: 11 pages, 4 figures, In 23rd ACM International Conference on Hybrid Systems: Computation and Control
Παιδαγωγική Εταιρεία Ελλάδας: δεκαεφτά χρόνια από την ίδρυση
Creators: name: Θωίδης, Δημήτριος
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1998

description: Παιδαγωγική Επιθεώρηση, Vol. 27 (1998)
Η μετάνοια και η εξομολόγηση κατά τον Συμεών τον Νέο Θεολόγο
Creators: name: Παλάνη, Δήμητρα Κωνσταντίνου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Μετάνοια
Εξομολόγηση
Συγχώρεση
Repentance
Confession
Forgiveness

description: Σκοπός της διατριβής ήταν η αντικειμενική και καλά τεκμηριωμένη από τους λόγους του ίδιου του Αγίου Συμεών του Νέου Θεολόγου παρουσίαση της διδασκαλίας του για το σωτήριο μυστήριο της Μετανοίας και Εξομολογήσεως. Εξετάσαμε την ιστορική πορεία και εξέλιξη του θεοσύστατου μυστηρίου της Εκκλησίας και παρουσιάσαμε τη θεώρηση της Μετανοίας ως δεύτερου Βαπτίσματος. Ακόμη αναφερθήκαμε αναλυτικά στα γνωρίσματα της γνήσιας μετανοίας προκειμένου να καταστεί δυνατή η σωτηρία του πιστού. Στη συνέχεια πραγματευτήκαμε την εξομολόγηση και τους λειτουργούς αυτής ώστε οι άνθρωποι να αξιωθούν να γίνουν μέτοχοι των θείων χαρισμάτων. Ασχοληθήκαμε επιπλέον με τις ωφέλειες που επιφέρει το μυστήριο αυτό σε όσους ολόψυχα μετανοούν και παρουσιάσαμε τη σύνδεσή του με τη Θεία Ευχαριστία που καθιστά τον πιστό υιό του Θεού και συγκληρονόμο της βασιλείας Του.
description: The propose of this dissertation was the objective and well-documented presentation of Saint Symeon’s the New Theologian teaching according to his own words concerning the salutary mystery of Repentance and Confession. We have thoroughly examined the historic course and evolution of the mystery founded by God and we presented the consideration of repentance as a second Baptism. Moreover we have elaborated on the features of a pure repentance aiming at rendering possible the worshippers’ salvation. Following this we dealt with the confession and its ministers so that people will have the right to relish the divine charismas. What is more, we also dealt with the benefits which are conferred by this mystery to all those people who wholeheartedly show repentance and we have presented its connection with the Holy Communion something which renders the worshipper son of God and co-heir of His kingdom.
Towards Mitigating Dimensional Collapse of Representations in Collaborative Filtering
Creators: name: Chen, Huiyuan
name: Lai, Vivian
name: Jin, Hongye
name: Jiang, Zhimeng
name: Das, Mahashweta
name: Hu, Xia
Publisher: name: arXiv
Year: 2023
Subjects: subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences

description: Contrastive Learning (CL) has shown promising performance in collaborative filtering. The key idea is to generate augmentation-invariant embeddings by maximizing the Mutual Information between different augmented views of the same instance. However, we empirically observe that existing CL models suffer from the \textsl{dimensional collapse} issue, where user/item embeddings only span a low-dimension subspace of the entire feature space. This suppresses other dimensional information and weakens the distinguishability of embeddings. Here we propose a non-contrastive learning objective, named nCL, which explicitly mitigates dimensional collapse of representations in collaborative filtering. Our nCL aims to achieve geometric properties of \textsl{Alignment} and \textsl{Compactness} on the embedding space. In particular, the alignment tries to push together representations of positive-related user-item pairs, while compactness tends to find the optimal coding length of user/item embeddings, subject to a given distortion. More importantly, our nCL does not require data augmentation nor negative sampling during training, making it scalable to large datasets. Experimental results demonstrate the superiority of our nCL.
Dual-decoder Transformer for Joint Automatic Speech Recognition and Multilingual Speech Translation
Creators: name: Le, Hang
name: Pino, Juan
name: Wang, Changhan
name: Gu, Jiatao
name: Schwab, Didier
name: Besacier, Laurent
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computation and Language (cs.CL)
subject: Sound (cs.SD)
subject: Audio and Speech Processing (eess.AS)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: We introduce dual-decoder Transformer, a new model architecture that jointly performs automatic speech recognition (ASR) and multilingual speech translation (ST). Our models are based on the original Transformer architecture (Vaswani et al., 2017) but consist of two decoders, each responsible for one task (ASR or ST). Our major contribution lies in how these decoders interact with each other: one decoder can attend to different information sources from the other via a dual-attention mechanism. We propose two variants of these architectures corresponding to two different levels of dependencies between the decoders, called the parallel and cross dual-decoder Transformers, respectively. Extensive experiments on the MuST-C dataset show that our models outperform the previously-reported highest translation performance in the multilingual settings, and outperform as well bilingual one-to-one results. Furthermore, our parallel models demonstrate no trade-off between ASR and ST compared to the vanilla multi-task architecture. Our code and pre-trained models are available at https://github.com/formiel/speech-translation.
description: Accepted at COLING 2020 (Oral)
Σύνθεση DNG διηλεκτρικής δομής για συλλογή μικροκυματικής ηλεκτρομαγνητικής ενέργειας από το περιβάλλον
Creators: name: Καραμπατέα, Αποστολία Στεφάνου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Διηλεκτρική δομή
Συλλογή ηλεκτρομαγνητικής ενέργειας
Μεταϋλικά
DNG
RF energy harvesting
metamaterials

description: Τα τελευταία χρόνια η ιδέα και οι τεχνικές για συλλογή και αξιοποίηση της μικροκυματικής ηλεκτρομαγνητικής ακτινοβολίας που υπάρχει συνεχώς στο περιβάλλον, προερχόμενη από ανθρωπογενείς πηγές, έχει αποτελέσει αντικείμενο εκτεταμένης και εντατικής έρευνας. Οι προτεινόμενες μεθοδολογίες στην πλειοψηφία τους περιλαμβάνουν τη χρήση κεραιών για τη συλλογή της ακτινοβολίας. Σαν εναλλακτικές τεχνικές προτείνονται η χρήση δομών ειδικής μορφής (Frequency selective surfaces ή Electromagnetic bandgap surfaces). Στην παρούσα εργασία προτείνεται μέθοδος με χρήση τεχνητών μεταϋλικών (Artificial Metamaterials) και συγκεκριμένα διηλεκτρικών δομών με συμπεριφορά τεχνητής αρνητικής ηλεκτρικής και μαγνητικής διαπερατότητας (Double Negative_DNG). Σχεδιάστηκαν δομές με τις ιδιότητες αυτές και μέσω ενός μηχανισμού που προτείνεται, αποδείχθηκε ότι μπορούν να λειτουργήσουν σαν συλλέκτες ηλεκτρομαγνητικής ακτινοβολίας. Οι θεωρητικές προσεγγίσεις του προβλήματος συνοδεύονται από αντίστοιχα αριθμητικά αποτελέσματα που παρουσιάζονται.
description: Recently, the concept and techniques of collection and utilization of microwave electromagnetic radiation, being constantly present in the environment and resulting from anthropogenic sources, have been topics of extensive and intensive research. Proposed methodologies mostly involve the use of antennas in order to collect radiation. The use of special form structures (Frequency Selective Surfaces or Electromagnetic Bandgap Surfaces) is proposed as alternative technique. In this dissertation, a method using artificial metamaterials and specific dielectric structures with artificial negative electrical permittivity and magnetic permeability (Double Negative), is proposed. Some structures with these properties have been designed, while through the proposed way, it’s proved that they can operate as collectors of electromagnetic radiation. The theoretical approaches to this problem are accompanied by the corresponding numerical results which are presented.
Vectorial dispersive shock waves on an incoherent landscape
Creators: name: Nuño, Javier
name: Finot, Christophe
name: Fatome, Julien
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We study numerically and experimentally the impact of temporal randomness on the formation of analogue optical blast-waves in nonlinear fiber optics. The principle-of-operation is based on a two-components nonlinear interaction occurring between a partially coherent probe wave co-propagating in a normally dispersive optical fiber together with an orthogonally polarized intense short pulse. The cross-polarized interaction induces a dual phase-singularity in the probe profile which leads to the formation of two sharp fronts of opposite velocities. An optical blast-wave is then generated and leads to an expanding rarefication area surrounded by two dispersive shock waves which regularize the shock onto the probe landscape. Here we focus our study on the impact of randomness in the shock formation. In particular, we show that the lack of coherence into the probe wave acts as a strong diffusive term, which is able to hamper or inhibit the shock formation. Our experimental observations are confirmed by numerical predictions based on a system of two incoherently coupled nonlinear Schr{ö}dinger Manakov equations.
description: arXiv admin note: text overlap with arXiv:1806.10439