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1.
In this paper, we discuss the problem of selecting suppliers for an organisation, where a number of suppliers have made price offers for supply of items, but have limited capacity. Selecting the cheapest combination of suppliers is a straightforward matter, but purchasers often have a dual goal of lowering the number of suppliers they deal with. This second goal makes this issue a bicriteria problem – minimisation of cost and minimisation of the number of suppliers. We present a mixed integer programming (MIP) model for this scenario. Quality and delivery performance are modelled as constraints. Smaller instances of this model may be solved using an MIP solver, but large instances will require a heuristic. We present a multi-population genetic algorithm for generating Pareto-optimal solutions of the problem. The performance of this algorithm is compared against MIP solutions and Monte Carlo solutions.  相似文献   
2.
移动IPv6中端到端Diffserv QoS上下文转移框架   总被引:1,自引:0,他引:1       下载免费PDF全文
提出了一种移动IPv6端到端的DiffServ上下文转移框架,采用COPS-SLS协议作为DiffServ在移动环境下的信令机制来实现端到端的域间SLS动态磋商,使用端到端的上下文转移方法来重建DiffServ上下文可以避免重新发起COPS-SLS信令,并且端到端的DiffServ上下文仅在新增加路径中的QB间进行转移。该方法能减少切换时的服务中断,当MN切换时,实时应用能迅速得到与切换前相同的转发处理。  相似文献   
3.
Wound healing impairment due to a postponed, incomplete, or uncoordinated healing process has been a challenging clinical problem. Much research has focused on wound care, particularly on discovery of new therapeutic approaches for acute and chronic wounds. This study aims to evaluate the effect of the combination of quercetin and curcuminoids at three different ratios on the antimicrobial, antioxidant, cell migration and wound healing properties. The antioxidant activities of quercetin, curcuminoids and the mixtures were tested by DPPH and ABTS free radical scavenging assays. The disc diffusion method was performed to determine the antibacterial activities of quercetin, curcuminoids and the mixtures against S. aureus and P. aeruginosa. The cytotoxicity and cell migratory enhancing effects of quercetin, curcuminoids and the mixtures against human dermal fibroblasts were investigated by MTT assay, scratch assay and Transwell migration assay, respectively. The results showed the synergism of the quercetin and curcuminoid combination to inhibit the growth of S. aureus and P. aeruginosa, with the inhibition zone ranging from 7.06 ± 0.25 to 8.78 ± 0.38 mm, respectively. The DPPH free radical scavenging assay demonstrated that the combination of quercetin and curcuminoids yielded lower IC50 values (15.38–23.70 µg/mL) than curcuminoids alone (25.75 µg/mL). Quercetin and a 3:1 quercetin/curcuminoid mixture at non-toxic concentrations showed the ability to stimulate the migration of fibroblasts across the matrix, whereas only quercetin alone accelerated the wound closure of fibroblasts. In conclusion, the mixture of quercetin and curcuminoids at a 3:1 ratio was the best formulations for use in wound healing due to the antimicrobial, antioxidant and cell-migration-enhancing activities.  相似文献   
4.
To assess the contribution of NaCl to seafood tastiness, 23Na and 35Cl nuclear magnetic resonance (NMR) spectroscopy was used to determine the mobility of sodium and chloride ions in intact snow crab (Chionoecetes japonicus) leg meat. The T1 (longitudinal relaxation time) values of both 23Na and 35Cl, obtained from inverse recovery experiments, show an evident variance with different heat‐processing methods. Heating tends to inhibit both sodium and chloride ion mobility. 35Cl NMR spectra indicate that chloride exists in two different chemical states, one derived from free ions and the other from organic base complexes. © 2000 Society of Chemical Industry  相似文献   
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对5种QoS接纳控制算法进行性能分析和比较。论文在NS2中构建了实验用的网络拓扑和流量,在RSVP信令下,对3种不同带宽利用率的网络场景进行了仿真,并对以上算法在各种场景下的丢包率、接入率、传输时延和时延抖动情况进行了分析和比较。  相似文献   
7.
针对汽车交流发电机性能自动化测试装置中测试对象特性的多样性及测试环境的多变性:在进行测试条件参数调节的过程中,采用改进型BP神经网络PID控制器,实现PID参数的在线自整定,改善自动化测试装置的动态品质,从而有效提高发电机生产线的生产效率。介绍了改进型BP神经网络控制器的构成和算法实现,利用MATLAB对其在自动化测试装置中发电机速度调节进行了仿真研究,表明了方法的有效性。  相似文献   
8.
随着网络的发展,越来越多的场景需要在不完整数据下进行近似成员查询,传统成员查询的布鲁姆过滤器不能满足上述要求。提出面向缺失数据的布鲁姆近似查询算法,先对高维不完整数据的缺失部分进行预填充,通过PCA算法,将高维数据转换到低维数据,使用局部敏感哈希函数与标准哈希函数结合的方式将低维数据存储到布鲁姆过滤器中。使用两个真实数据集验证了所提算法的功能,所提面向缺失数据的布鲁姆近似查询算法,能有效地解决存在缺失数据的近似成员查询问题。  相似文献   
9.
IP服务质量的研究   总被引:2,自引:0,他引:2  
IP服务质量已成为IP网络的研究热点,Internet面临的最大挑战之一是在IP网络中给不断涌现的各种应用提供区分的QoS性能保证。综述了IP服务质量的产生背景、当前的解决方案及相关的QoS技术支持。对当前IP QoS的两个主要模型进行了性能比较。  相似文献   
10.
Analysis of acrylamide by LC-MS/MS and GC-MS in processed Japanese foods.   总被引:12,自引:0,他引:12  
Acrylamide concentrations in processed foods (63 samples covering 31 product types) from Japan were analysed by LC-MS/MS and GC-MS methods. The limit of detection and limit of quantification of acrylamide were 0.2 ng x ml(-1) (6 fmol) and 0.8 ng x ml(-1) (22 fmol), respectively, by LC-MS/MS, and those of 2,3-dibromopropionamide derived from acrylamide were 12 ng x ml(-1) (52 fmol) and 40 ng x ml(-1) (170 fmol), respectively, by GC-MS. Repeatability given as RSD was <5 and <15% for the LC-MS/MS and GC-MS methods, respectively. High correlation (r(2) - 0.946) was observed between values obtained by the two methods. Most potato crisps and whole potato-based fried snacks showed acrylamide concentrations >1000 microg x kg(-1). The concentrations in non-whole potato-based snacks, rice crackers processed by grilling or frying, and candied sweet potatoes were lower compared with those in the potato crisps and the whole potato-based fried snacks. One of the whole potato-based fried snacks, however, showed low acrylamide concentration (<50 microg x kg(-1)) suggesting the formation of acrylamide is strongly influenced by processing conditions. Acrylamide concentrations in instant precooked noodles and won-tons were <100 microg x kg(-1) with only one exception. Roasted barley grains for 'Mugi-cha' tea contained 200-600 microg x kg(-1) acrylamide.  相似文献   
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