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排序方式: 共有6086条查询结果,搜索用时 15 毫秒
981.
Khaled El Emam 《Empirical Software Engineering》1999,4(2):113-133
Software process assessments are by now a prevalent tool for process improvement and contract risk assessment in the software industry. Given that scores are assigned to processes during an assessment, a process assessment can be considered a subjective measurement procedure. As with any subjective measurement procedure, the reliability of process assessments has important implications on the utility of assessment scores, and therefore the reliability of assessments can be taken as a criterion for evaluating an assessment's quality. The particular type of reliability of interest in this paper is interrater agreement. Thus far, empirical evaluations of the interrater agreement of assessments have used Cohen's Kappa coefficient. Once a Kappa value has been derived, the next question is “how good is it?” Benchmarks for interpreting the obtained values of Kappa are available from the social sciences and medical literature. However, the applicability of these benchmarks to the software process assessment context is not obvious. In this paper we develop a benchmark for interpreting Kappa values using data from ratings of 70 process instances collected from assessments of 19 different projects in 7 different organizations in Europe during the SPICE Trials (this is an international effort to empirically evaluate the emerging ISO/IEC 15504 International Standard for Software Process Assessment). The benchmark indicates that Kappa values below 0.45 are poor, and values above 0.62 constitute substantial agreement and should be the minimum aimed for. This benchmark can be used to decide how good an assessment's reliability is. 相似文献
982.
NY Walton BM Uthman K El Yafi JM Kim DM Treiman 《Canadian Metallurgical Quarterly》1999,40(2):153-156
Paraneoplastic pemphigus (PNP) is an autoimmune blistering disease that occurs in association with underlying neoplasms. PNP patients develop characteristic autoantibodies directed against multiple antigens, mostly identified as members of the plakin family of cytoplasmic proteins (desmoplakin I and II, bullous pemphigoid antigen I, envoplakin, and periplakin). HD1/plectin, another member of the plakin family, has not previously been detected in the characteristic PNP antigen complex, which may relate to practical difficulties associated with its large size (molecular weight approximately 500 kDa). In this study, a combination of immunoprecipitation and immunoblot is used to demonstrate that HD1/plectin is also recognized by sera from PNP patients. Thirteen of 16 PNP sera tested were positive for HD1/plectin compared with none of 43 control sera (11 pemphigus vulgaris, 11 pemphigus foliaceus, 11 bullous pemphigoid, and 10 normal individuals). Combined with our recent finding that desmoglein 3 and desmoglein 1 are cell surface target antigens in PNP, this demonstration of plectin/HD1 as another component of the antigen complex in PNP confirms that PNP is an autoimmune disease against desmoglein and plakin family molecules. 相似文献
983.
Naciye El Levent Dandik H. Ayşe Aksoy 《Journal of the American Oil Chemists' Society》1998,75(12):1207-1211
The solvent-free glycerolysis of used sunflower oil catalyzed by acetone powder of Nigella sativa seeds was investigated. The highest partial acylglycerols yield was obtained at 60°C. The glycerolysis reactions, conducted
at molar ratios of 1:1, 2:1, and 3:1 of oil to glycerol keeping the acetone powder content at 30% based on oil weight and
the temperature at 60°C, approached equilibrium after 2 h. The highest partial acylglycerol content of the products was 66%
(1:1 molar ratio) and 60% (2:1 molar ratio). 相似文献
984.
985.
Experimental Study on Deoxidization of Barium and Barium Alloy 总被引:2,自引:0,他引:2
1.Experimeotal1.1ConvectionfreebatheXPerjmentsThepurposeofconvectionfreebathexperimelltswastoacquiremoltenironsysteminwhichthedeoxi-dizationproducts(firstoriginalinclusions)wouldnotbeaffectedbytheinnercirculationflowcausedbyconvection.TheregUlarityofbariumdeoxidizationcanbestudiedbasedonthefirstoriginalinclusions.Duringtheexperimentalperiod,thedirectcurrentmolybdenum-woundfurnacewasusedinwhichtheex-ternalforcecausedbythealternatemagneticfieldwaseliminated.Themicrocomputertemperaturecolltrols… 相似文献
986.
Preciptated solid materials (PSM) from waste black liquor (WBL), at pH 8·5–9·0, produced from cooking of rice straw in paper
mill factories were thermally treated. The cooking process led to decrease in organic material and partial substitution in
silica structure. During this cooking process, three probable stages of mass loss comprise removal of moisture, volatile release,
and combustion.
The chemical analysis depicts the cooking effect on leaching either the high percentage elements (Ca, Na, and K) or some metallic
cations (Mn, Cd, Zn and Cu) in the parent rice straw. Silica hydrate, amorphous silica and crystalline silica were obtained
at <600°C, 600–700°C and at>800°C, respectively. The infrared spectra show gradual removal of the hydrocarbon bond (C–H),
molecular H2O, and sianol group (Si-OH) with temperature. TG, DTA, XRD and SEM were used in this study. 相似文献
987.
988.
Samah M S El‐Shafei Sally S Sakr Nagwa H I Abou‐Soliman 《International Journal of Dairy Technology》2020,73(1):126-133
This study investigated the impact of supplementing goats' milk with quinoa extracts, in the range of 5, 10 and 15 g/100 g on the milk fermentation. The properties of yoghurt produced from this milk, which include viscosity, microstructure and sensory acceptability, were assessed. The supplementation of goats' milk with quinoa extracts, particularly permeate extract, reduced the fermentation time and enhanced the viability of lactic acid bacteria. Supplementation of yoghurt with increased levels of quinoa extracts increased the apparent viscosity and changed the yoghurt protein matrix. Panellists highly accepted the yoghurt that contained quinoa permeate extract. 相似文献
989.
Antioxidant activities of enzymatic‐hydrolysed proteins of dromedary (Camelus dromedarius) colostrum
Olfa Oussaief Zeineb Jrad Isabelle Adt Mohamed Dbara Touhami Khorchani Halima El‐Hatmi 《International Journal of Dairy Technology》2020,73(2):333-340
This work investigated the antioxidant activities of dromedary colostrum proteins before and after hydrolysis by pepsin, trypsin, α‐chymotrypsin, pancreatin and papain. The enzymatic hydrolysis affected the degrees of hydrolysis, electrophoretic profiles, molecular weight distribution and hydrophobic/hydrophilic properties of the generated peptides. The antioxidant activities were evaluated using four antioxidant assays, including 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) radical‐scavenging activities, ferric reducing power and ferrous ion chelating activity. Interestingly, the antioxidant activities of dromedary colostrum proteins were enhanced after enzymatic hydrolysis. The highest antioxidant potential was obtained by pancreatic hydrolysates (P ≤ 0.05). These results suggest that dromedary colostrum protein hydrolysates are an important source of natural antioxidant peptides. 相似文献
990.
H. H. Abou El Naga E. S. H. El Ashry M. A. Khattab A. E. Salem Y. M. Boghdady 《Lubrication Science》2001,13(3):251-271
This paper describes work aimed at producing a high‐quality transformer oil from local Egyptian paraffinic base stock by hydrogenation, or hydrogenation plus sulphonation. Analysis showed that the neutral base oil 70N was suitable for producing transformer oil. This neutral base oil was chemically treated by hydrogenation under various conditions of temperature, pressure, and time, using two different catalysts, and by hydrogenation followed by sulphonation using optimum conditions. Optimum hydrogenation conditions were achieved by using a Ni/Mo (10 wt. %) catalyst, at 275°C and 100 psi pressure for 60 min, while optimum sulphonation conditions were achieved in previous work by using oleum or SO3 gas at a concentration of 6 wt. % at 35°C for 60 min. Laboratory results and field trials indicated that the neutral paraffinic base oil when so treated meets the IEC 296 international specification for transformer oil, with the exception of the pour point (−18°C). However, this pour point is not relevant in certain hot climatic conditions. Evaluation of the treated oil with commercial transformer oil has shown its potential for use. 相似文献