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61.
基于遗传算法的分布式异构数据库的查询优化 总被引:2,自引:1,他引:2
对于分布武异构数据库,查询优化问题是其核心问题。本文用基于位、值结构树型编码的遗传算法对分布武异构数据库进行查询优化,取得了很好的效果。 相似文献
62.
Fatigue of bituminous mixtures 总被引:1,自引:0,他引:1
H. Di Benedetto C. de La Roche H. Baaj A. Pronk R. Lundström 《Materials and Structures》2004,37(3):202-216
This paper presents an interlaboratory test campaign organized by the RILEM 182-PEB Technical Committee. In the campaign,
11 different test methods, comprising uniaxial tension/compression, 2-, 3- and 4-point bending and indirecttension tests,
were utilized in order to investigate fatigue characteristics of a dense graded asphalt concrete mixture. The testing conditions
specified were sinusoidal excitation at 10Hz and 10°C using controlled strain and stress modes. In total, more than 150 fatigue
tests were carried out during the investigation. The fatigue test results were analyzed using both classical as well as continuum
damage mechanics approaches. The fatigue test results obtained using the classical fatigue approach are considerably influenced
by test type and mode of loading (controlled stress or strain) used. Consequently, this approach has limited use in realistic
fatigue characterization of bituminous materials and pavement structures. In contrast to the classical approach, models founded
on continuum damage theory may serve to isolate intrinsic fatigue characteristics from the influence of so-called biased effects,
which are largely caused by the accelerated laboratory testing. The continuum damage models investigated may constitute steps,
towards a rational mechanistic fatigue characterization model, which are important for effective future pavement design. 相似文献
63.
64.
This 6-year longitudinal study examined girls' peer-nominated social preference and aggression in childhood as predictors of self- and parent-reported externalizing symptoms, substance use (i.e.. cigarette, alcohol, and marijuana use), and sexual risk behavior in adolescence. Participants were 148 girls from diverse ethnic backgrounds, who were initially assessed in Grades 4-6 and again in Grades 10-12. Results supported a moderator model, indicating that social preference changed the nature of the association between childhood aggression and adolescent outcomes. When accompanied by peer rejection, aggressive behavior was moderately stable over time and significantly associated with adolescent girls' substance use and sexual risk behavior. However, under conditions of peer acceptance, no significant association between childhood aggression and adolescent outcomes emerged. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
Marc Rennhard Sandro Rafaeli Laurent Mathy Bernhard Plattner David Hutchison 《Electronic Commerce Research》2004,4(1-2):83-111
The lack of privacy is one of the main reasons that limits trust in e-commerce. Current e-commerce practice enforces a customer to disclose her identity to the e-shop and the use of credit cards makes it straightforward for an e-shop to know the real identity of its customers. Although there are some payment systems based on untraceable tokens, they are not as widely used as credit cards. Furthermore, even without buying anything, a customer is already disclosing some information about who or where she may be by just connecting to the e-shop's web server and leaving behind an IP-address. In this paper, we present novel components that enable secure pseudonymous e-commerce. On the one hand, these components allow a customer to browse through an e-shop, select goods, and pay the goods with her credit card such that neither the e-shop operator nor the credit card issuer nor an eavesdropper is able to get any information about the customer's identity. On the other hand, it is guaranteed that none of the involved parties is able to act dishonestly during the credit card payment. Such a system could greatly enhance trust in e-commerce since it overcomes the customers' privacy concerns. 相似文献
66.
Ariel La Paz Jos M. Merig Philip Powell Arkalgud Ramaprasad Thant Syn 《Information Systems Journal》2020,30(3):431-457
The Information Systems Journal (ISJ) published its first issue in 1991, and in 2015, the journal celebrated its 25th anniversary. This study presents an overview of the leading research trends in the papers that the journal has published during its first quarter of a century via a bibliometric and ontological analysis. From a bibliometric perspective, the analysis considers the publication and citation structure of the journal. The study then develops a graphical analysis of the bibliographic material by using visualization of similarities software that employs bibliographic coupling and cocitation analysis. The work produces an ontological framework of impact and analyses the journal papers to assess qualitatively ISJ's impact. The results indicate that the journal has grown significantly over time and is now recognized as one of the leading journals in information systems. Yet challenges remain if the journal is to meet its aims in impacting and setting the agenda for the development of the Information Systems field. 相似文献
67.
68.
Mauro Vigan Nicola Pugliese Federica Cerini Federica Turati Vincenzo Cimino Sofia Ridolfo Simone Rocchetto Francesca Foglio Maria Terrin Carlo La Vecchia Maria Grazia Rumi Alessio Aghemo 《International journal of molecular sciences》2022,23(20)
The identification of advanced fibrosis by applying noninvasive tests is still a key component of the diagnostic algorithm of NAFLD. The aim of this study is to assess the concordance between the FIB-4 and liver stiffness measurement (LSM) in patients referred to two liver centers for the ultrasound-based diagnosis of NAFLD. Fibrosis 4 Index for Liver Fibrosis (FIB-4) and LSM were assessed in 1338 patients. A total of 428 (32%) had an LSM ≥ 8 kPa, whereas 699 (52%) and 113 (9%) patients had an FIB-4 < 1.3 and >3.25, respectively. Among 699 patients with an FIB-4 < 1.3, 118 (17%) had an LSM ≥ 8 kPa (false-negative FIB-4). This proportion was higher in patients ≥60 years, with diabetes mellitus (DM), arterial hypertension or a body mass index (BMI) ≥ 27 kg/m2. In multiple adjusted models, age ≥ 60 years (odds ratio (OR) = 1.96, 95% confidence interval (CI) 1.19–3.23)), DM (OR = 2.59, 95% CI 1.63–4.13), body mass index (BMI) ≥ 27 kg/m2 (OR = 2.17, 95% CI 1.33–3.56) and gamma-glutamyltransferase ≥ 25 UI/L (OR = 2.68, 95% CI 1.49–4.84) were associated with false-negative FIB-4. The proportion of false-negative FIB-4 was 6% in patients with none or one of these risk factors and increased to 16, 31 and 46% among those with two, three and four concomitant risk factors, respectively. FIB-4 is suboptimal to identify patients to refer to liver centers, because about one-fifth may be false negative at FIB-4, having instead an LSM ≥ 8 KPa. 相似文献
69.
为了更全面、合理的评价丁香精油作为防腐保鲜剂对病原菌生长的控制效应及毒素合成间的相关性,以熏蒸的方式,通过离体和活体实验,研究了不同浓度的丁香精油对扩展青霉生长和毒素分泌的影响。结果表明,固体培养中,26.0μL/L的丁香精油熏蒸对扩展青霉的孢子萌发、菌体生长和毒素分泌均起到明显的抑制作用;虽然在液体培养和活体实验中,相同浓度的丁香精油熏蒸抑制菌体生长同时促进了毒素分泌,但是在这两种实验模式下,当丁香油浓度达到130μL/L以上时,才达到同时抑制生长和产毒的效果。因此,将丁香精油作为防腐保鲜剂开发时,需同时考虑其对展青霉素分泌的影响,以期达到抑菌效果和食用安全性。 相似文献
70.
Aniello Maiese Alice Chiara Manetti Naomi Iacoponi Eleonora Mezzetti Emanuela Turillazzi Marco Di Paolo Raffaele La Russa Paola Frati Vittorio Fineschi 《International journal of molecular sciences》2022,23(13)
The vitality demonstration refers to determining if an injury has been caused ante- or post-mortem, while wound age means to evaluate how long a subject has survived after the infliction of an injury. Histology alone is not enough to prove the vitality of a lesion. Recently, immunohistochemistry, biochemistry, and molecular biology have been introduced in the field of lesions vitality and age demonstration. The study was conducted according to the preferred reporting items for systematic review (PRISMA) protocol. The search terms were “wound”, “lesion”, “vitality”, “evaluation”, “immunohistochemistry”, “proteins”, “electrolytes”, “mRNAs”, and “miRNAs” in the title, abstract, and keywords. This evaluation left 137 scientific papers. This review aimed to collect all the knowledge on vital wound demonstration and provide a temporal distribution of the methods currently available, in order to determine the age of lesions, thus helping forensic pathologists in finding a way through the tangled jungle of wound vitality evaluation. 相似文献