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排序方式: 共有1299条查询结果,搜索用时 46 毫秒
31.
Luiz Marcio Cysneiros Julio Cesar Sampaio do Prado Leite Jaime de Melo Sabat Neto 《Requirements Engineering》2001,6(2):97-115
The development of complex information systems calls for conceptual models that describe aspects beyond entities and activities.
In particular, recent research has pointed out that conceptual models need to model goals, in order to capture the intentions
which underlie complex situations within an organisational context. This paper focuses on one class of goals, namely non-functional
requirements (NFR), which need to be captured and analysed from the very early phases of the software development process.
The paper presents a framework for integrating NFRs into the ER and OO models. This framework has been validated by two case
studies, one of which is very large. The results of the case studies suggest that goal modelling during early phases can lead
to a more productive and complete modelling activity. 相似文献
32.
This review is an account of the origin and migratory events of primordial germ cells until their settlement in the gonad before sexual differentiation in the human as well as mice. In this context, the morphodynamic characteristics of the migration of the primordial germ cells, the macromolecular characteristics of the extracellular matrix of the migratory pathway, and the factors involved in the germ cell guidance have been analyzed and discussed in the light of recent advances in this field, by means of immunocytochemical procedures. The events prior to gonadal morphogenesis and the origin of the somatic cell content of the human gonadal primordium have been also analyzed. In particular, evidences are presented showing that cells derived from the coelomic epithelium and mesenchyme are at the origin of the somatic components of the gonadal primordium, and that a mesonephric cell contribution to the generation of somatic cell components of the genital ridge in humans should be discarded due to the morphological stability of the different nephric structures during the period preceding the sexual differentiation of the gonad. 相似文献
33.
The use of crack growth resistance curves (R–a) to predict the behaviour of cracked specimens is a well established practice for ceramic and cementitious materials. When the cohesive crack model can be applied to these materials it is shown that the use of R–a curves is equivalent to setting up an elastic equivalence that greatly simplifies the computations. This equivalence has its drawbacks and limitations. This paper analyzes a class of equivalences—the load (P) versus another variable—between cracked cohesive materials and linear elastic ones, ascertaining its applicability to the interpretations of fracture data. 相似文献
34.
A key process for post-secondary educational institutions is the definition of course timetables and classroom assignments. Manual scheduling methods require enormous amounts of time and resources to deliver results of questionable quality, and multiple course and classroom conflicts usually occur. This article presents a scheduling system implemented in a Web environment. This system generates optimal schedules via an integer-programming model. Among its functionalities, this system enables direct interaction with instructors in order to gather data on their time availability for teaching courses. The results demonstrate that significant improvements over the typical fully manual process were obtained. 相似文献
35.
36.
L. Civale B. Maiorov A. Serquis J. O. Willis J. Y. Coulter H. Wang Q. X. Jia P. N. Arendt M. Jaime J. L. MacManus-Driscoll M. P. Maley S. R. Foltyn 《Journal of Low Temperature Physics》2004,135(1-2):87-98
The main challenges for the success of high temperature superconducting wires, the YBa2Cu3O7 (YBCO) coated conductors (CC), are to avoid the the weak-link problem through the production of biaxially textured films, and to increase the critical current density (J c) through the introduction of large densities of appropriate defects. To that end, it is essential to understand the pinning mechanisms and their correlation with the microstructure of the CC. We first present a brief overview of the main methods currently used to produce YBCO CC, and we describe the architecture of the YBCO on IBAD fabricated at Los Alamos, summarizing the recent improvements of their structural and superconducting properties. Then, we analyze some aspects of the J c dependence on temperature and magnetic field (orientation and intensity) for the best CC available, and we compare and contrast the results with those of YBCO thin films on single crystal substrates, in order to determine if the defects controlling the pinning mechanisms are the same in both cases. Our results indicate that over large field and angular ranges J c on CC is higher than J c in thin films on SCS. 相似文献
37.
Ram n G mez-Aguilar Jaime Ortiz-L pez 《Fullerenes, Nanotubes and Carbon Nanostructures》2004,12(4):731-744
The AC conductivity and dielectric constant of polycrystalline and amorphous C70 samples were measured in the 75-300 K temperature range and in the 100 Hz to 1 MHz frequency range. For polycrystalline samples, we observe effects caused by O2 intercalation due to prolonged exposure to ambient air. The conductivity σ of these samples around 300 K depends on the measuring frequency ν as a σ ∼ νn with n ≈ 0.88, implying a strong reduction of DC conductivity to less than 10-12 S/cm. The dielectric constant of polycrystalline samples shows an anomaly at 285 K which is interpreted as due to the transition from its intermediate rhombohedral phase into its monoclinic low-temperature phase. In contrast with the polycrystalline samples, the amorphous C70 samples prepared by sublimation do not contain interstitial 02, their conductivity at 300 K is of about 10-6 S/cm, is independent of frequency, and is well described by the hopping mechanism (Davis-Mott T1/4 law) in the 200-300 K range. All evidence of phase transitions disappears in the amorphous samples. 相似文献
38.
39.
Kelwin Fernandes Jaime S. Cardoso Birgitte Schmidt Astrup 《Pattern Analysis & Applications》2018,21(3):629-640
Despite the existence of patterns able to discriminate between consensual and non-consensual intercourse, the relevance of genital lesions in the corroboration of a legal rape complaint is currently under debate in many countries. The testimony of the physicians when assessing these lesions has been questioned in court due to several factors (e.g., a lack of comprehensive knowledge of lesions, wide spectrum of background area, among others). Therefore, it is relevant to provide automated tools to support the decision process in an objective manner. In this work, we evaluate the performance of state-of-the-art deep learning architectures for the forensic assessment of sexual assault. We propose a deep architecture and learning strategy to tackle the class imbalance on deep learning using ranking. The proposed methodologies achieved the best results when compared with handcrafted feature engineering and with other deep architectures. 相似文献
40.
Villachica Carlos Clemente-Jul Carmen Villachica Joyce Villachica Leslye Llamosas Jaime 《Mine Water and the Environment》2021,40(1):23-35
Mine Water and the Environment - Tailings size distribution can be modified to greatly reduce surface storage area and the risk of catastrophic tailings dam failures. Total flotation and backfill... 相似文献