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991.
Requirements engineering (RE) offers the means to discover, model, and manage the requirements of the products that comprise a product line, while software product line engineering (SPLE) offers the means of realizing the products’ requirements from a common base of software assets. In practice, however, RE and SPLE have proven to be less complementary than they should. While some RE techniques, particularly goal modeling, support the exploration of alternative solutions, the appropriate solution is typically conditional on context and a large product line may have many product-defining contexts. Thus, scalability and traceability through into product line features are key challenges for RE. Feature modeling, by contrast, has been widely accepted as a way of modeling commonality and variability of products of a product line that may be very complex. In this paper, we propose a goal-driven feature modeling approach that separates a feature space in terms of problem space and solution space features, and establish explicit mappings between them. This approach contributes to reducing the inherent complexity of a mixed-view feature model, deriving key engineering drivers for developing core assets of a product line, and facilitating the quality-based product configuration. 相似文献
992.
Dong Won Cho Young Hae Lee Tae Youn Lee Mitsuo Gen 《Journal of Intelligent Manufacturing》2014,25(5):1025-1042
In this paper we propose an adaptive genetic algorithm that produces good quality solutions to the time dependent inventory routing problem (TDIRP) in which inventory control and time dependent vehicle routing decisions for a set of retailers are made simultaneously over a specific planning horizon. This work is motivated by the effect of dynamic traffic conditions in an urban context and the resulting inventory and transportation costs. We provide a mixed integer programming formulation for TDIRP. Since finding the optimal solutions for TDIRP is a NP-hard problem, an adaptive genetic algorithm is applied. We develop new genetic representation and design suitable crossover and mutation operators for the improvement phase. We use adaptive genetic operator proposed by Yun and Gen (Fuzzy Optim Decis Mak 2(2):161–175, 2003) for the automatic setting of the genetic parameter values. The comparison of results shows the significance of the designed AGA and demonstrates the capability of reaching solutions within 0.5 % of the optimum on sets of test problems. 相似文献
993.
Hyoun-Ee Kim Arthur J. Moorhead Doh-Hyung Riu Dong-Han Lee 《Journal of the American Ceramic Society》1995,78(6):1708-1710
Sintered α-SiC was exposed, for times up to 2 h, to a flowing wet H2 atmosphere ( P H2 O = 1 × 10-4 MPa) at temperatures of 1300°, 1400°, and 1500°C. The effect of such conditions on the reliability of the ceramic was estimated by comparing the Weibull modulus of the groups of specimens, tested in four-point flexure, before and after exposure. The Weibull modulus of as-polished specimens was 6.7, indicating a wide variation in room-temperature flexural strength. The Weibull modulus was increased to 14.2 by the heat treatment for 2 h in wet H2 at 1400°C. The average strength was also improved from 347 to 446 MPa by such exposure. Heat treatment at 1300° and 1500°C also improved the reliability of the material, as indicated by increases in the Weibull modulus, but to less a degree than did exposure at 1400°C. The increases in reliability and average strength were attributed to the blunting of surface flaws by the formation of a thin SiO2 layer on the sample surface. 相似文献
994.
Summary The surface modification of low-density polyethylene(PE) by liquid phase photograft polymerization with acrylic acid(AA), acrylamide(AM) and glycidyl methacrylate(GMA) was described. The grafting of AA and AM was proved and characterized by electron spectroscopy for chemical analysis(ESCA). It was found that fully hydrophilic surface can be obtained in very short irradiation time. With ESCA and attenuated total reflection infrared spectroscopy(ATR-IR), it can be confirmed that bifunctional monomer GMA was grafted onto the PE film surface. Through further reaction with GMA grafted film, heparin and protamine were immobilized onto the grafted film surface. 相似文献
995.
铬酸酐副产物硫酸氢钠的利用 总被引:1,自引:0,他引:1
对生产铬酸酐时副产的含铬硫酸氢钠的利用作了评论,介绍了8种方法,即,化学沉淀法、磷酸沉淀法、铬酸铬法、电解氧化法、过硫酸钠氧化法、制商品硫酸氢钠、酸泥制碱式硫酸铬、硫酸氢钠制碱式硫酸铬,其中以化学沉淀法、磷酸沉淀法和铬酸铬法应用最广。 相似文献
996.
Experimental cloud-point data to 260 °C and 2,500 bar are reported to demonstrate the impact of two cosolvents, acetone and
methanol, on the phase behavior of polyethylene, poly(ethylene-co-2.4 mol% acrylic acid) (EAA2.4), poly(ethylene-co-3.9 mol% acrylic acid) (EAA3.9), poly(ethylene-co-6.9 mol% acrylic acid) (EAA6.9), and poly(ethylene-co-9.2 mol% acrylic acid) (EAA9.2) in ethylene. In pressure-temperature (P-T) space, the miscibility of EAA copolymers in ethylene decreases significantly
with temperature and with increasing acrylic acid content of EAA due to self-association of the acrylic acid segments. Acetone
and methanol, both dramatically enlarge the solubility of EAA copolymers due to the hydrogen bonding with acrylic acids in
the EAA. At low concentrations, methanol is a better cosolvent than acetone. However, the impact of methanol diminishes rapidly
with increasing methanol concentration once all the acrylic acids in the EAA are hydrogen bond with methanol molecules. 相似文献
997.
Do Ik Lee 《Progress in Organic Coatings》2002,45(4):341-358
The immobilization and consolidation of model coatings based on monodisperse polystyrene (plastic pigment) and S/B latexes of known particle sizes were studied in terms of their packing volumes and the extent of latex shrinkage, which was found to increase with increasing pigment volume up to the critical pigment volume concentration (CPVC). The maximum latex shrinkage was estimated from the CPVC. Then, the porosity of model coatings was calculated based on three proposed latex shrinkage models: maximum, minimum, and linearly decreasing latex shrinkage. The number of pores and the average equivalent spherical pore diameters were subsequently calculated. The opacity and gloss of model coatings on polyester films were measured and their porosity was also determined by a simple coat weight-thickness method. The CPVC values determined by the opacity, gloss, and porosity versus PVC relationships, respectively, agreed very well with each other. The CPVCs determined by the opacity and porosity versus PVC curves were identical. The comparison between the theoretically calculated and experimental porosity values showed that the linearly decreasing value between the maximum and minimum latex shrinkage would best fit the experimental porosity data. The effect of plastic pigment particle size on the optical properties and porosity of model coatings was also studied and it was observed that the coating opacity and porosity increased with increasing plastic pigment particle size, but the gloss decreased. Additionally, a minimum crack-free temperature (MCFT) of latex-bound coatings was proposed to better predict the behaviors of latexes as pigment binders. The wet state of model coating dispersions, the surfaces of consolidated model coatings, and their internal structure were examined by both electron and atomic force microscopy, and their micrographs were found to be consistent with our immobilization and consolidation models. 相似文献
998.
999.
This review paper summarizes current research efforts toward a comprehensive view of wet material dewatering, considering the binding energy as the strength to hold water, and rupture energy given to remove moisture from materials. 相似文献
1000.
Allard A. Cossé Julie L. Todd Jocelyn G. Millar Lee Ann Martínez Thomas C. Baker 《Journal of chemical ecology》1995,21(11):1823-1836
We have identified five compounds from the headspace of calling male Mediterranean fruit flies (medfly),Ceratitis capitata (Wiedemann), and three compounds from the headspace of ripe mango (Mangifera indica L). using coupled gas chromatographic-electroantennographic (GC-EAG) recordings, coupled gas chromatographic-mass spectrometric (GC-MS) analysis, and electroantennographic (EAG) assays of standards. The male-produced volatiles eliciting responses from female antennae were ethyl-(E)-3-octenoate, geranyl acetate, (E,E)--farnesene, linalool, and indole. An EAG dose-response test of linalool enantiomers and indole with female medfly antennae showed relatively strong EAG activities, but no significant difference between (R)-(-)-linalool and (S)-(+)-linalool. The three mango volatiles were identified as (1S)-(-)--pinene, ethyl octanoate, and-caryophyllene. In addition, a strong antennal response was recorded from a contaminant,-copaene, present in a commercial sample of-caryophyllene. The EAG response amplitudes from both male and female antennae to the above three mango volatiles were significantly greater than to a hexanol control. For both male and female medfly antennae, the greatest EAG responses were elicited by-caryophyllene followed by ethyl octanoate. The mean EAG responses of female antennae to-caryophyllene and (1S)-(-)--pinene were significantly greater than those of male antennae. 相似文献