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Fracturing process and effect of fracturing degree onwave velocity of a crystalline rock

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第5期9卷 797-806页

作者： Charalampos Saroglou vasileios Kallimogiannis Department of Geotechnical Engineering School of Civil Engineering National Technical University of Athens Athens Greece

The present paper investigates the effect of fracturing degree on P-and S-wave velocities in *** deformation of intact brittle rocks under loading conditions is characterized by a microcracking procedure,which occurs due to flaws in their microscopic structure and propagates through the intact rock,leading to shear *** fracturing process is of fundamental significance as it affects the mechanical properties of the rock and hence the wave *** order to determine the fracture mechanism and the effect of fracturing degree,samples were loaded at certain percentages of peak strength and ultrasonic wave velocity was recorded after every *** fracturing degree was recorded on the outer surface of the sample and quantified by the use of the indices P;（traces of joints/m）,P;（traces of joints/m;） and P;（length of fractures/m;）.It was concluded that the wave velocity decreases exponentially with increasing fracturing ***,the fracturing degree is described adequately with the proposed ***,other parameters concerning the fracture characteristics,rock type and scale influence were found to contribute to the velocity decay and need to be investigated further.

关键词： Wave velocity Fracturing Crack initiation Damage Granite

Malware-Propagative Mobile Ad Hoc Networks:Asymptotic Behavior Analysis

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Journal of Computer Science & Technology 2008年第3期23卷 389-399页

作者： vasileios Karyotis Anastasios Kakalis Symeon Papavassiliou Network Management and Optimal Design Lab(NETMODE) School of Electrical and Computer Engineering National Technical University of Athens(NTUA)AthensGreece

In this paper, the spreading of malicious software over ad hoc networks, where legitimate nodes are prone to propagate the infections they receive from either an attacker or their already infected neighbors, is analyzed. Considering the Susceptible-Infected-Susceptible （SIS） node infection paradigm we propose a probabilistic model, on the basis of the theory of closed queuing networks, that aims at describing the aggregated behavior of the system when attacked by malicious nodes. Because of its nature, the model is also able to deal more effectively with the stochastic behavior of attackers and the inherent probabilistic nature of the wireless environment. The proposed model is able to describe accurately the asymptotic behavior of malware-propagative large scale ad hoc networking environments. Using the Norton equivalent of the closed queuing network, we obtain analytical results for its steady state behavior, which in turn is used for identifying the critical parameters affecting the operation of the network. Finally, through modeling and simulation, some additional numerical results are obtained with respect to the behavior of the system when multiple attackers are present, and regarding the time-dependent evolution and impact of an attack.

关键词： wireless ad hoc networks infection efficiency closed queuing networks

Identifying important habitats for waterbird conservation at a Greek Regional Nature Park

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Avian Research 2020年第4期11卷 452-464页

作者： Vasilios Liordos vasileios J.Kontsiotis Hellenic Forest Service 12 Minoas str19100 MegaraAttikiGreece Department of Forest and Natural Environment Sciences International Hellenic UniversityP.O.Box 17266100 DramaGreece.

Background:Small coastal wetlands are vital sites for wintering *** important habitats is critical for managing waterbirds *** Vourkari inlet is a small coastal wetland located near the capital Athens,within the most urbanized and industrialized area of *** aimed at identifying the most important habitats for waterbirds at the Vourkari inlet during ***:Data about habitat use and availability were collected for 14 waterbird species and for seven habitat *** selection(Manly’s selection ratio),overlap indices(Pianka’s niche overlap index)and null models were ***:All the studied waterbird species selected available habitats *** waters(0–2 m),were used by 13 waterbirds and selected by five *** and channels were used and selected by 10 *** was used by nine species and selected by six *** with rocky substrate was used by nine species and selected by eight ***(2–4 m)and deep(4–6 m)open water habitats were used by seven species and selected by four *** vegetation was used by six species and selected by two *** habitats were selected by nationally important populations:mudflat habitats(i.e.,mud,mud with rocky substrate and pools and channels)by Common Redshanks(Tringa totanus),halophytic vegetation by Little Egrets(Egretta garzetta),shallow waters by Common Shelducks(Tadorna tadorna)and medium and deep waters by Sandwich Terns(Thalasseus sandvicencis),whilst shallow waters and mudflat habitats were preferred by a possibly internationally important population of Mediterranean Gulls(Ichthyaetus melanocephalus).Although overlap in habitat use between species was generally low,null models indicated habitat sharing and a lack of ***:Waterbirds coexisted in the absence of competition for habitats at Vourkari,where they mostly used and preferred shallow water and *** coastal wetlands are numerous,

关键词： Habitat selection Habitat use Mudflats Niche overlap Null models Open water Small coastal wetlands

Modeling and optimization of non-isothermal convective drying process of Lavandula×allardii

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Information Processing in Agriculture 2024年第1期11卷 1-13页

作者： vasileios Chasiotis Konstantinos-Stefanos Nikas Andronikos Filios Laboratory of Thermo Fluid Systems(LTFS) Department of Mechanical EngineeringUniversity of West AtticaAncient Olive Grove CampusThivon Str.250GR12244 EgaleoGreece

Non-isothermal convective drying schemes were examined for Lavandula×allardii leaves and *** process parameters were optimized using response surface methodology(RSM)to ensure the peak operational *** effects of temperature increase rate(2–4°C/h)and the airflow velocity(1–3 m/s)on the essential oil yield,drying duration and consumption,were investigated.A face-centered central composite design was deployed and the experimental data was adapted to the most suitable polynomial models,as determined by the regression *** of variance was applied to assess the effects of the process variables,their interactions and the statistical significance of the examined *** factors of temperature increase rate and airflow velocity had a significant impact on the drying *** velocity had a greater effect on leaves’essential oil yield and inflorescences’process energy consumption,whereas the rates of temperature increase had a greater influence on the inflorescences’essential oil yield and leaves’energy *** minimum drying duration and energy consumption were obtained for the maximum temperature increasing rate at 3 and 1 m/s airflow velocities respectively;and the highest essential oil yield was obtained for the least rate of temperature increase and airflow velocity for both leaves and *** optimization was performed for minimizing drying duration and energy consumption by maximizing the essential oil *** rate of temperature increases of 4°C/h and the airflow velocity of 1 m/s,were proposed as the optimum non-isothermal drying conditions for both leaves and inflorescences of Lavandula×*** values of essential oil content have been 1.387/3.05 mL/g,4.21/4.18 h drying time and 0.809/0.732 kWh energy consumption at the optimum operation point for leaves and inflorescences,*** resulted optimized non-stationary temperature scheme considerably improved the drying

关键词： Convective drying Non-isothermal drying Lavender Essential oil Process optimization

Review of incidence and outcomes of treatment of cholangiocarcinoma in patients with primary sclerosing cholangitis

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World Journal of Gastrointestinal Oncology 2021年第10期13卷 1336-1366页

作者： Francesca Saffioti vasileios K Mavroeidis Department of Gastroenterology and Hepatology Oxford University Hospitals NHS Foundation TrustOxford OX39DUOxfordshireUnited Kingdom UCL Institute for Liver and Digestive Health and Sheila Sherlock Liver Unit Royal Free HospitalUniversity College LondonLondon NW32QGUnited Kingdom Department of Surgery The Royal Marsden NHS Foundation TrustLondon SW36JJUnited Kingdom Department of Transplant Surgery North Bristol NHS TrustSouthmead HospitalBristol BS105NBUnited Kingdom

Primary sclerosing cholangitis(PSC)is a premalignant condition and a welldocumented risk factor for cholangiocarcinoma(CCA)which is the most common malignancy in this setting and the leading cause of deaths in the recent years,with an increasing ***-associated CCA has a geographical distribution that follows the incidence of PSC,with an observed ascending gradient from the Eastern to the Western and from the Southern to the Northern *** may arise at any location along the biliary tree but is most common in the perihilar *** with PSC and intrahepatic or perihilar CCA are typically not suitable for liver resection,which is otherwise the treatment of choice with curative intent in patients with resectable tumours,providing a radical resection with clear margins can be *** largely relates to the commonly advanced stage of liver disease at presentation,which allows consideration for liver resection only for a very limited number of suitable patients with *** the other hand,remarkable progress has been reached in the last decades with the implementation of a protocol combining neoadjuvant chemoradiation and orthotopic liver transplantation(OLT)for the treatment of perihilar CCA,within specific *** results have been achieved particularly for PSC patients with this cancer,who seem to benefit the most from this treatment,having converted this into an accepted indication for transplantation and the standard of care in several experienced *** CCA as an indication for OLT remains controversial and has not been accepted given disappointing previous ***,as recent studies have shown favourable outcomes in early intrahepatic CCA,it may be that under defined criteria,OLT may play a more prominent role in the *** CCA in the context of PSC requires aggressive surgical treatment with curative intent,when *** review provides insight about particular features of CCA in the setting of

关键词： Cholangiocarcinoma Primary sclerosing cholangitis Liver resection Liver transplantation Neoadjuvant therapy Adjuvant therapy

POPULISM IN POWER?A RECONSIDERATION OF THE ATHENIAN DEMOCRACY OF THE LATE 5TH CENTURY BC

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Journal of Ancient Civilizations 2022年第1期37卷 33-63,143页

作者： vasileios Adamidis Nottingham Trent University

The Athenian demokratia of the late 5th century BC exhibited characteristics which would today qualify as populist.1Indeed,this was already the conclusion of an earlier paper which attempted to identify intersections ... 详细信息

关键词： conclusion attempted intersection

Metasurfaces: physics and applications in wireless communications

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National Science Review 2023年第8期10卷 48-63页

作者： vasileios G. Ataloglou Sajjad Taravati George V. Eleftheriades The Edward S.Rogers Sr.Department of Electrical and Computer Engineering University of Toronto Clarendon Laboratory Department of Physics University of Oxford

The ever increasing number of wireless devices and systems has led to a crowded spectrum and increased the demand for versatile and multi-functional wireless apparatuses. Recently, metasurfaces have been explored as a prominent technological solution to the current paradigm of spectrum scarcity by opportunistically sharing the spectrum with various users. In general, metasurfaces are passive/dynamic,ultra-compact, multi-functional and programmable structures that are capable of both reciprocal and nonreciprocal signal-wave transmissions. The controllability and programmability of such metasurfaces are governed through DC bias and occasionally a radio-frequency modulation applied to the active components of the unit cells of the metasurface, e.g. diodes and transistors. This article overviews some of the recently proposed passive and dynamic metasurfaces and shows that metasurfaces can enhance the performance of wireless communication systems thanks to their unique physical features such as real-time signal coding,nonreciprocal-beam radiation, nonreciprocal beamsteering amplification and advanced pattern-coding multiple access communication.

关键词： metasurface beamsteering beamforming wireless communication time modulation wave engineering

Potential of hybrid adaptive filtering in inflammatory lesion detection from capsule endoscopy images

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World Journal of Gastroenterology 2016年第39期22卷 8641-8657页

作者： vasileios S Charisis Leontios J Hadjileontiadis Department of Electrical and Computer Engineering Aristotle University of Thessaloniki Department of Electrical and Computer Engineering Khalifa University

A new feature extraction technique for the detection of lesions created from mucosal inflammations in Crohn's disease, based on wireless capsule endoscopy(WCE) images processing is presented here. More specifically, a novel filtering process, namely Hybrid Adaptive Filtering(HAF), was developed for efficient extraction of lesion-related structural/textural characteristics from WCE images, by employing Genetic Algorithms to the Curvelet-based representation of images. Additionally, Differential Lacunarity(DLac) analysis was applied for feature extraction from the HAF-filtered images. The resulted scheme, namely HAF-DLac, incorporates support vector machines for robust lesion recognition performance. For the training and testing of HAFDLac, an 800-image database was used, acquired from 13 patients who undertook WCE examinations, where the abnormal cases were grouped into mild and severe, according to the severity of the depicted lesion, for a more extensive evaluation of the performance. Experimental results, along with comparison with other related efforts, have shown that the HAF-DLac approach evidently outperforms them in the field of WCE image analysis for automated lesion detection, providing higher classification results, up to 93.8%(accuracy), 95.2%(sensitivity), 92.4%(specificity) and 92.6%(precision). The promising performance of HAF-DLac paves the way for a complete computer-aided diagnosis system that could support physicians' clinical practice.

关键词： Capsule endoscopy Curvelet Ulcer Genetic algorithms Crohn’s disease

Understanding stakeholder preferences for managing red foxes in different situations

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Ecological Processes 2020年第1期9卷 222-235页

作者： Vasilios Liordos vasileios J.Kontsiotis Foteini Emmanouilidou Department of Forestry and Natural Environment International Hellenic UniversityP.O.Box 17266100 DramaGreece

Background:Red foxes(Vulpes vulpes)have historically been interacting with human societies,thus being an important component of socio-ecological *** Greece,farmers and hunters have been increasingly complaining about predation of red foxes on livestock and game,and the recurrence of rabies incidents has raised concerns about human and animal *** public preferences about management is necessary for successful wildlife *** study aimed at investigating the preferences of north Greece residents for managing the negative impacts of red foxes and also at understanding variation between stakeholder groups:farmers,hunters,farmers-hunters,and the general *** were collected from on-site face-to-face surveys(n=746),between March and May *** were asked to rate their acceptability of management strategies under three impact scenarios:red foxes attack livestock,reduce game,and carry ***:Stakeholders preferred nonlethal management strategies,with generally high consensus,both between and within *** and compensation were the most acceptable strategies for protecting livestock and vaccination and the removal of sick animals for eliminating *** and consensus for lethal strategies were lower,with hunting being the most acceptable lethal strategy for hunters,especially when foxes threatened game or carried *** nothing was becoming more unacceptable and lethal control more acceptable with increasing severity of the impacts,i.e.,livestock and game predation versus rabies ***:Variation in the acceptability of and consensus for management strategies was considerable among scenarios,and both between and within stakeholder *** implications could be used as a guide for reaching consensus for proper management strategies during the conservation conflict management process in the study *** similar studies are scarce,findings might also prove useful elsewh

关键词： Canids Farmers Hunters Potential for conflict index Conservation conflict management Northeast Mediterranean