In many applications, especially from the business domain, the requirements specification mainly deals with use cases and
class models. Unfortunately, these models are based on different modelling techniques and aim at different levels of abstraction,
such that serious consistency and completeness problems are induced. To overcome these deficiencies, we refine activity graphs
to meet the needs for a suitable modelling element for use case behaviour. The refinement in particular supports the proper
coupling of use cases via activity graphs and the class model. The granularity and semantics of our approach allow for a seamless,
traceable transition of use cases to the class model and for the verification of the class model against the use case model.
The validation of the use case model and parts of the class model is supported as well. Experience from several applications
has shown that the investment in specification, validation and verification not only pays off during system and acceptance
testing but also significantly improves the quality of the final product. 相似文献
E-commerce has embraced the digital transformation and innovated with e-service touchpoints to improve customers’ experiences. Now some traditional, less-digitalized brick and mortar (BaM) retailers are starting to counteract the increasing competition by adopting digital touchpoints. However, the academic literature offers little in terms of what determines customers’ behavioral intentions toward e-service touchpoints. Therefore, drawing from the dominant design theory, this article first conceptually adapts selected dominant touchpoints of leading e-commerce solutions to BaM retail. Then 250 shoppers are surveyed regarding the likeliness that they will use the selected touchpoints, followed by an exploratory factor analysis to determine the touchpoints’ characteristics that lead to the shoppers’ assessments. The results suggest that customers prefer touchpoints that support product search and selection, provide information, and increase shopping efficiency. The likeliness that surveyed shoppers will use the touchpoints was affected by the functionality provided, the content conveyed, and the mediating device. The results provide a foundation for further research on customers’ behavioral intentions toward BaM e-service touchpoints and provide useful information for BaM retailers.
Using pig slurry as starter fertilizer for maize (Zea mays L.), injected below the row prior to planting is a reasonable way to omit application of additional mineral fertilizer in areas with intensive animal farming. However, delayed early growth and a lack of knowledge on nutrient availability limit the interest of farmers. To extenuate farmers concerns a field trial was conducted in 2014 and 2015 to get detailed information on nitrogen (N) uptake, the subsequent influences on crop growth at different vegetative growth stages and final yield of silage maize. Besides an unfertilized control, two liquid manure injection treatments (without and with nitrification inhibitor [NI]) were compared to slurry broadcast application + mineral N and phosphorus (P) starter fertilizer at planting (MSF). In 2014, NI treatment yields increased (+16.5%) and N uptake increased (+9.6%) compared to broadcast treatment. In 2015, cold and dry conditions during early growth limited P plant availability and reduced crop growth in treatments without MSF. However, when a NI was added to the slurry prior to application, plants showed less P deficiency symptoms and better growth. At harvest no differences between the fertilized treatments were observed. In both years apparent N recovery was increased when manure was injected (48% without, and 56% with NI, respectively) compared to broadcast application of manure (43%) indicating that N losses were lower. However, further knowledge on soil N transformation and N loss pathways in systems with slurry injection is needed. 相似文献
Purpose Increased T2 signal intensity (SI) can be regularly observed in myocardial infarction. However, there are controversial reports
about the relationship of elevated T2 SI to myocardial viability and some authors propose that high T2 SI serves as a sign
of irreversible myocardial injury. This study investigates increased T2 SI compared to myocardial function in patients with
reperfused subacute myocardial infarction. Preserved function was used as criterion for viability.
Methods Ten healthy volunteers and 17 patients with myocardial infarction and patent inlarct related coronary artery were examined
on a 1.5 T Magnetom Vision system (Siemens). For T2-weighted MR imaging a breath-hold STIR sequence with dark-blood preparation
was used. Cine FLASH 2D imaging was applied to assess myocardial function. Signal-to-noise (S/N) in STIR T2 images was measured
in normal and infarcted regions and subsequently identified by two independent observers. Based on a 20 segment model of the
left ventricle findings were compared to regional myocardial function.
Results Elevated STIR T2 SI was found in all 17 patients and observed in 27% (204/754) of segments. S/N of normal myocardium was 5.1
±0.7 in volunteers and 4.9 ± 0.8 in patients(P=NS). Infarcted myocardium presented with significantly-increased S/N 12.8 ± 1.9 (P < 0.0001). Significant transmural elevation of T2 SI was noted in 32% of segments with preserved systolic function.
Conclusion Increased STIR T2 SI can be observed transmurally in post-ischemic myocardial regions with preserved function. It therefore
cannot be used as an exclusive marker for the non-viable region. 相似文献
The UK-TO single wash test procedure, developed to be diagnostic of the oxidative bleach response of dyed articles to repeated washing in activated oxygen bleach-containing detergents, has been subjected to extensive interlaboratory trials. The results indicate that both its repeatability and reproducibility are fully acceptable for the purpose of interlaboratory comparisons. 相似文献
The gene greA was cloned from the genome of the basidiomycete Suillus grevillei. It encodes a monomodular natural product biosynthesis protein composed of three domains for adenylation, thiolation, and thioesterase and, hence, is reminiscent of a nonribosomal peptide synthetase (NRPS). GreA was biochemically characterized in vitro. It was identified as atromentin synthetase and therefore represents one of only a limited number of biochemically characterized NRPS-like enzymes which accept an aromatic α-keto acid. Specificity-conferring amino acid residues-collectively referred to as the nonribosomal code-were predicted for the primary sequence of the GreA adenylation domain and were an unprecedented combination for aromatic α-keto acids. Plausible support for this new code came from in silico simulation of the adenylation domain structure. According to the model, the predicted residues line the active site and, therefore, very likely contribute to substrate specificity. 相似文献
Signaling molecules affecting patterning processes are usually proteins and rarely peptides. Two novel peptides, pedibin and Hym-346, that are closely related to one another have been isolated from Hydra vulgaris and Hydra magnipapillata. Several experiments indicate that both cause a reduction in the positional value gradient, the principle patterning process governing the maintenance of form in the adult hydra. The peptides cause an increase in the rate of foot regeneration following bisection of the body column. Treatment of animals with either peptide for an extended period of time resulted in an apical extension of the range of expression of CnNk-2 along the body column. Such an extension is correlated with a decrease in positional value. Transplantation of tissue treated with Hym-346 results in an increase in the fraction forming feet, and aggregates derived from Hym-346 tissue form more feet and fewer heads. The latter two experiments provide a direct measure of the lowering of positional value in the treated tissue. These results suggest that peptides play signaling roles in patterning processes in cnidaria and, plausibly, in more complex metazoans as well. 相似文献
Age-related macular degeneration (AMD) was used as a case model to longitudinally study adaptation in affective well-being under a prevalent chronic health condition. Measures of positive and negative affect, obtained at 5 subsequent measurement occasions with 3-month intervals in between, were analyzed in 90 older adults diagnosed with AMD. The authors proposed a pattern of adaptation that shows initial decline in affective well-being after disease outbreak, followed by a turnaround into a restorative phase of increase, implying nonlinear intraindividual trajectories, with changes substantially related to disease duration. Analysis was conducted by means of a nonlinear mixed models approach. Results confirmed the hypothesized adaptation pattern for positive affect but not for negative affect, which was found more stable across measurement occasions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献