170,434 research outputs found
Numerical investigation of the structural role of vertical connectors between drums in ancient columns
No full textThe present paper is part of a research program, aiming to investigate the effect of vertical
connectors (gomfoi) on the seismic behaviour of columns and colonnades, in ancient Monuments.
The columns in ancient Monuments are constructed following the dry construction system, i.e., large
dimensions structural members (marble or porous stones, depending on the importance of the monument and
the availability of materials at the vicinity of the construction site) are positioned without mortar. Since the
Classical Era, connectors are used for the better connection of the consecutive drums. The system of “poloiempolia”, which are of cylindrical shape, positioned in the centre of the drum, is in many cases replaced, or
co-esixts in the Hellenistic and Roman Era, by vertical connectors of orthogonal parallelepiped shape (gomfoi),
positioned near the edges of the drums.
The dimensions and the positions of the vertical connectors (gomfoi) in ancient columns have been
documented, based on published work and in situ observation, in monuments in Greece. Among the
investigated monuments, the Gymnasium in Ancient Messene has been chosen for further analytical and
experimental investigation. Preliminary numerical modelling and analysis (under seismic actions) of single
columns has been performed, using two different types of numerical modelling, namely a finite element and a
discrete element program. The results of the different procedures are presented here and are commented
upon. The columns are modelled without connectors, in order to study the effect of the number and the height
of the drums in the behaviour of the columns. The original column, consisting of three drums and a capital, is
modelled also with vertical connectors, and the structural role of the connectors is commented upon. The
modelling of the columns leads to the selection of the exact geometry of the columns to be tested, the expected
actions on the interfaces, the required characteristics of the seismic excitations to be imposed to them, etc. as
well as to the adequate design of the specimens and the setup for the shaking table tests
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
L’INÉGAL DÉVELOPPEMENT INDUSTRIEL DE LA CHINE : CAPACITÉS D’INNOVATION ET COEXISTENCE DE DIFFÉRENTS MODES D’APPRENTISSAGE TECHNOLOGIQUE
No full textBased on the example of the automobile and electronics sector in China, the article examines the technological learning of companies in China and the way it is influenced by industrial policy. Companies have consolidated their production capacity and technological learning but are rarely in the position to develop an innovation capability. The article shows the diversity of enterprises and identifies two opposing modes of development, either based on technological transfers of foreign technologies mainly through state-owned enterprises, or based on assimilation and learning of technologies acquired through the clients in private or foreign-owned companies or other new enterprises, of a rather small size. The latter are less favoured by official policies and have difficulties in obtaining the advantages that may have been available through the national innovation system (training, higher education, research, technical centres, funding). This separation of the innovation system promoted by the government and the industrial system that was created through technological learning is, in the authors’ opinion, the main reason for a low innovation capability of the Chinese industry. The co-existence of these two different modes is a characteristic feature of China and explains why China does not follow the “imitation to innovation” path experiences by South Korea and Japan.CHINE, DÉVELOPPEMENT INDUSTRIEL, APPRENTISSAGE TECHNOLOGIQUE, ENTREPRISES, TRANSFERTS DE TECHNOLOGIE, POLITIQUE INDUSTRIELLE, SYSTÈME NATIONAL D?INNOVATION
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Towards Automated and Fast Whisker Tracking in Rodents
No full textWhisker tracking in rodents is an ongoing research in neuroscience. Neuroscientists have recorded experiments with high-speed cameras in which untrimmed, head-restrained mice are provided with air stimuli. These videos required the development of algorithms to reliably track whisker movement. Recently, a Whisker Tracking System, WhiskEras, emerged, which is able to detect and track whiskers over the course of such videos in a more accurate way than pre-existing methods. WhiskEras is slow, processing less than 1 frame per second. Additionally, it involves a great number of parameters which need tuning for different experimental setups and recording settings which were used for this experiment. This thesis addresses these two problems. First, the algorithm was examined and its shortcomings were exposed. A more accurate whisker point detection algorithm was suggested and implemented, among a range of alternative solutions which were studied. Furthermore, its Stitching stage was modified to replace a range of hard-to-tune parameters with more robust ones. Finally, the improved WhiskEras was accelerated by porting the MATLAB code to C++ and using advanced parallelization techniques with CUDA and OpenMP to achieve a speedup of 74.96. Overall, the improvements yielded better tracking results in our benchmarks, while the parameters were much easier to tune and remained constant under different video setups of whisking experiments.Electrical Engineering | Embedded System
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
A 0.12mm<sup>2</sup> Wien-Bridge Temperature Sensor with 0.1°C (3σ) Inaccuracy from -40°C to 180°C
No full text Resistor-based temperature sensors can achieve much higher resolution and energy efficiency than conventional BJT-based sensors [1], but they typically occupy more area (> 0.25 mm 2 ) and have lower operating temperatures (le 125 {circ} {C}) [2]-[4]. This work describes a 0.12mm 2 resistor-based sensor that uses a Wien-bridge (WB) filter to achieve 0.1 {circ} {C} (3 sigma) inaccuracy from - 40 {circ} {C} to 180 {circ} {C}. Compared to a state-of-the-art WB sensor [4], it occupies 6 × less area and achieves comparable relative accuracy over a 76% wider operating range. Session 10.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Moving forward in the Euro-Mediterranean research and innovation partnership : the experience of the MIRA project
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