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291.
Memory efficiency is important for processing high-volume data streams. Previous stream-aggregation methods can exhibit excessive memory overhead in the presence of skewed data distributions. Further, data skew is a common feature of massive data streams. The authors introduce the AdaptWID algorithm, which uses adaptive processing to cope with time-varying data skew. AdaptWID models the memory usage of alternative aggregation algorithms and selects between them at runtime on a group-by-group basis. The authors' experimental study using the NiagaraST stream system verifies that the adaptive algorithm improves memory usage while maintaining execution cost and latency comparable to existing implementations. 相似文献
292.
Ioanna Nikitopoulou Dionysios Fanidis Konstantinos Ntatsoulis Panagiotis Moulos George Mpekoulis Maria Evangelidou Alice G. Vassiliou Vasiliki Dimakopoulou Edison Jahaj Stamatios Tsipilis Stylianos E. Orfanos Ioanna Dimopoulou Emmanouil Angelakis Karolina Akinosoglou Niki Vassilaki Argyrios Tzouvelekis Anastasia Kotanidou Vassilis Aidinis 《International journal of molecular sciences》2021,22(18)
Autotaxin (ATX; ENPP2) is a secreted lysophospholipase D catalyzing the extracellular production of lysophosphatidic acid (LPA), a pleiotropic signaling phospholipid. Genetic and pharmacologic studies have previously established a pathologic role for ATX and LPA signaling in pulmonary injury, inflammation, and fibrosis. Here, increased ENPP2 mRNA levels were detected in immune cells from nasopharyngeal swab samples of COVID-19 patients, and increased ATX serum levels were found in severe COVID-19 patients. ATX serum levels correlated with the corresponding increased serum levels of IL-6 and endothelial damage biomarkers, suggesting an interplay of the ATX/LPA axis with hyperinflammation and the associated vascular dysfunction in COVID-19. Accordingly, dexamethasone (Dex) treatment of mechanically ventilated patients reduced ATX levels, as shown in two independent cohorts, indicating that the therapeutic benefits of Dex include the suppression of ATX. Moreover, large scale analysis of multiple single cell RNA sequencing datasets revealed the expression landscape of ENPP2 in COVID-19 and further suggested a role for ATX in the homeostasis of dendritic cells, which exhibit both numerical and functional deficits in COVID-19. Therefore, ATX has likely a multifunctional role in COVID-19 pathogenesis, suggesting that its pharmacological targeting might represent an additional therapeutic option, both during and after hospitalization. 相似文献
293.
With the proliferation of spatial and spatio-temporal data that are produced everyday by a wide range of applications, Geographic
Information Systems (GIS) have to cope with millions of objects with diverse spatial characteristics. Clearly, under these
circumstances, substantial performance speed up can be achieved with the use of spatial, spatio-temporal and other multi-dimensional
indexing techniques. Due to the increasing research effort on developing new indexing methods, the number of available alternatives
is becoming overwhelming, making the task of selecting the most appropriate method for indexing the data according to application
needs rather challenging. Therefore, developing a library that can combine a variety of indexing techniques under a common
application programming interface can prove to be a valuable tool. In this paper we present SaIL (SpAtial Index Library), an extensible framework that enables easy integration of spatial and spatio-temporal index structures
into existing applications. We focus on design issues and elaborate on techniques for making the framework generic enough,
so that it can support user defined data types, customizable spatial queries, and a broad range of spatial (and spatio-temporal)
index structures, in a way that does not compromise functionality, extensibility and, primarily, ease of use. SaIL is publicly
available and has already been successfully utilized for research and commercial applications.
This work was conducted while the first author was visiting ESRI and was partially supported by ESRI, NSF grants IIS-9907477,
EIA-9983445, and IIS-0220148. 相似文献
294.
Castillejo M Martin M Oujia M Silva D Torres R Manousaki A Zafiropulos V van den Brink OF Heeren RM Teule R Silva A Gouveia H 《Analytical chemistry》2002,74(18):4662-4671
The cleaning of paintings using UV lasers is a growing field of interest in the practice of conservation. In this work, we have studied the chemical and physical changes induced by KrF excimer laser at 248 nm of tempera paint dosimeter systems. The changes have been evaluated by using a range of analytical techniques. These include profilometry; colorimetry; optical and vibrational spectroscopies, such as laser-induced fluorescence (LIF), laser-induced breakdown spectroscopy (LIBS), Fourier transform Raman (FTR), and infrared (FT-IR); and analytical mass spectrometric techniques, such as direct-temperature-resolved mass spectrometry (DTMS) and matrix-assisted laser desorption and ionization mass spectrometry (MALDI-MS). Integration of the results obtained by these techniques allowed the investigation of the nature and degree of change of the irradiated paint systems. Direct laser irradiation induces various degrees of discoloration that depend strongly on the nature of the pigment. This effect takes place mainly on the surface layer of the sample. Degradation of the binding medium occurs in the presence of inorganic pigments, and in some cases, evidence of alterations in the molecular composition of the pigment has been obtained. Varnished systems do not display this discoloration when a thin protective layer is left on the paint. A laser cleaning strategy for varnished paintings should be based on the partial removal of the varnish, leaving a residual layer that shields the underlying pigments from direct laser exposure. 相似文献
295.
Matsopoulos GK Kouloulias V Asvestas P Mouravliansky N Delibasis K Demetriades D 《Computer methods and programs in biomedicine》2004,76(1):53-71
In this paper a World Wide Web (WWW)-based medical system, called MITIS, is designed and developed for the management and processing of obstetrical, gynecological and radiological medical data. The system records all the necessary medical information in terms of patient data, examinations, and operations and provides the user-expert with advanced image processing tools for the manipulation, processing and storage of ultrasound and mammographic images. The system can be installed in a hospital's Local Area Network (LAN) where it can access picture archival and communication systems (PACS) servers (if available), or any other server within the radiology department, for image archiving and retrieval, based on the digital imaging and communication in medicine (DICOM) 3.0 protocol, over TCP/IP and also it is accessible to external physicians via the hospital's Internet connection. MITIS is composed as a set of independent WWW modules (ISAPI server extension dlls) and a Win32 application (COM+ server) for mammography image processing and evaluation. 相似文献
296.
Dimitris Th. Askounis Vassilis Assimakopoulos John Psarras 《Journal of Intelligent Manufacturing》1994,5(5):323-331
Fault tolerance in computerized systems involved in production has become an ever more important requirement. Existing fault tolerance approaches, wherever used, deal mainly with hardware faults. Nevertheless, the vast majority of contemporary system failures are software related. This paper introduces a knowledge-based approach to handling software related faults occurring in supervisory control systems. These systems are event driven and use data, stored in complex databases, to react to events coming from different kinds of devices by identifying, scheduling, initiating and monitoring operations. Failure of part of the supervisory control system's software to behave rationally when unexpected events occur is called an application fault. The approach introduced in this paper is based on a supervisory control system reference model which reveals the set of all possible application faults together with the major functions of the recovery processes associated with each fault, and leads to a high-level knowledge-based system architecture capable of handling every fault-related condition. This system is called PROFIT (Intelligent PROduction systems Fault Tolerance) and consists of three main components: the fault diagnosis module, the instant fault correction module and the learning module, co-ordinated by a PROFIT meta-level module. The prototype version of PROFIT is analysed and the development as well as the run-time environment that prove the applicability and effectiveness of the system are presented. 相似文献
297.
Marios Hadjieleftheriou George Kollios Vassilis J. Tsotras Dimitrios Gunopulos 《The VLDB Journal The International Journal on Very Large Data Bases》2006,15(2):143-164
Spatiotemporal objects – that is, objects that evolve over time – appear in many applications. Due to the nature of such applications,
storing the evolution of objects through time in order to answer historical queries (queries that refer to past states of
the evolution) requires a very large specialized database, what is termed in this article a spatiotemporal archive. Efficient processing of historical queries on spatiotemporal archives requires equally sophisticated indexing schemes. Typical
spatiotemporal indexing techniques represent the objects using minimum bounding regions (MBR) extended with a temporal dimension,
which are then indexed using traditional multidimensional index structures. However, rough MBR approximations introduce excessive
overlap between index nodes, which deteriorates query performance. This article introduces a robust indexing scheme for answering
spatiotemporal queries more efficiently. A number of algorithms and heuristics are elaborated that can be used to preprocess
a spatiotemporal archive in order to produce finer object approximations, which, in combination with a multiversion index structure, will greatly improve query performance in comparison to the straightforward approaches. The proposed techniques introduce
a query efficiency vs. space tradeoff that can help tune a structure according to available resources. Empirical observations
for estimating the necessary amount of additional storage space required for improving query performance by a given factor
are also provided. Moreover, heuristics for applying the proposed ideas in an online setting are discussed. Finally, a thorough
experimental evaluation is conducted to show the merits of the proposed techniques.
Edited by B. Seeger
A short version of this article appeared as “Efficient indexing of spatiotemporal objects” in the Proceedings of Extending
Database Technology 2002 [19]. This work was partially supported by NSF grants IIS-9907477, EIA-9983445, NSF IIS 9984729,
NSF ITR 0220148, NSF IIS-0133825, NRDRP, and the U.S. Department of Defense. 相似文献
298.
Catherine Gabriel Olga Tsave Maria P. Yavropoulou Theodore Architektonidis Catherine P. Raptopoulou Vassilis Psycharis Athanasios Salifoglou 《International journal of molecular sciences》2021,22(13)
Diabetes mellitus is a debilitating disease, plaguing a significant number of people around the globe. Attempts to develop new drugs on well-defined atoxic metalloforms, which are capable of influencing fundamental cellular processes overcoming insulin resistance, has triggered an upsurge in molecular research linked to zinc metallodrugs. To that end, meticulous efforts were launched toward the design and synthesis of materials with insulin mimetic potential. Henceforth, trigonelline and N-(2-hydroxyethyl)-iminodiacetic acid (HeidaH2) were selected as organic substrates seeking binding to zinc (Zn(II)), with new crystalline compounds characterized by elemental analysis, FT-IR, X-rays, thermogravimetry (TGA), luminescence, NMR, and ESI-MS spectrometry. Physicochemical characterization was followed by in vitro biochemical experiments, in which three out of the five zinc compounds emerged as atoxic, exhibiting bio-activity profiles reflecting enhanced adipogenic potential. Concurrently, well-defined qualitative–quantitative experiments provided links to genetic loci responsible for the observed effects, thereby unraveling their key involvement in signaling pathways in adipocyte tissue and insulin mimetic behavior. The collective results (a) signify the quintessential role of molecular studies in unearthing unknown facets of pathophysiological events in diabetes mellitus II, (b) reflect the close associations of properly configured molecular zincoforms to well-defined biological profiles, and (c) set the stage for further physicochemical-based development of efficient zinc antidiabetic metallodrugs. 相似文献
299.
Dietary fiber suspensions from olive mill wastewater as potential fat replacements in meatballs 总被引:1,自引:0,他引:1
A dietary fiber containing material, named as alcohol insoluble residue (AIR), was recovered from the olive mill wastewater (OMW). It was separated into different fractions (water soluble and insoluble AIR) and characterized with regard to fiber and ion content. Dynamic rheological tests of the water soluble fraction (WSAIR) were conducted in order to examine its gelling ability. Thereafter, AIR as well as WSAIR were utilized as fat replacement in meatballs together or separately with carrot and starch and compared with regard to the total, water and fat loss or oil uptake during frying of the meatballs. Results indicated that AIR could not be considered as a potential fat replacement in meatballs due to the restricted water holding ability. Nevertheless, WSAIR could be utilized together with carrot fibers as additive in low fat meatballs, since it was able to improve the cooking properties of the product, by restricting the oil uptake and thereby giving rise to meatballs with sustained reduced fat content. 相似文献
300.
Athanasios S. Alexandris Yiqing Wang Constantine E. Frangakis Youngrim Lee Jiwon Ryu Zahra Alam Vassilis E. Koliatsos 《International journal of molecular sciences》2022,23(13)
White matter pathology is common across a wide spectrum of neurological diseases. Characterizing this pathology is important for both a mechanistic understanding of neurological diseases as well as for the development of neuroimaging biomarkers. Although axonal calibers can vary by orders of magnitude, they are tightly regulated and related to neuronal function, and changes in axon calibers have been reported in several diseases and their models. In this study, we utilize the impact acceleration model of traumatic brain injury (IA-TBI) to assess early and late changes in the axon diameter distribution (ADD) of the mouse corticospinal tract using Airyscan and electron microscopy. We find that axon calibers follow a lognormal distribution whose parameters significantly change after injury. While IA-TBI leads to 30% loss of corticospinal axons by day 7 with a bias for larger axons, at 21 days after injury we find a significant redistribution of axon frequencies that is driven by a reduction in large-caliber axons in the absence of detectable degeneration. We postulate that changes in ADD features may reflect a functional adaptation of injured neural systems. Moreover, we find that ADD features offer an accurate way to discriminate between injured and non-injured mice. Exploring injury-related ADD signatures by histology or new emerging neuroimaging modalities may offer a more nuanced and comprehensive way to characterize white matter pathology and may also have the potential to generate novel biomarkers of injury. 相似文献