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41.
配电网重构一般采用对单一目标优化,而配电网重构却是一个多目标优化问题。因此,在此提出了基于小生境思想的遗传算法,以配电网的经济性、安全性和供电可靠性为目标,并采用Pareto寻优方式,得出Pareto最优解集,实现了和以往不同的另一种寻优方式,即先寻优后决策。在寻优过程中,通过小生境环境和交叉率和变异率的自适应机制,提高了遗传算法的全局收敛能力和收敛速度,并通过算例验证了方法的有效性。 相似文献
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Natalia-Del Pilar Vanegas Paola Fernanda Ruiz-Aparicio Gloria Ins Uribe Adriana Linares-Ballesteros Jean-Paul Vernot 《International journal of molecular sciences》2021,22(15)
Leukemic cell growth in the bone marrow (BM) induces a very stressful condition. Mesenchymal stem cells (MSC), a key component of this BM niche, are affected in several ways with unfavorable consequences on hematopoietic stem cells favoring leukemic cells. These alterations in MSC during B-cell acute lymphoblastic leukemia (B-ALL) have not been fully studied. In this work, we have compared the modifications that occur in an in vitro leukemic niche (LN) with those observed in MSC isolated from B-ALL patients. MSC in this LN niche showed features of a senescence process, i.e., altered morphology, increased senescence-associated β-Galactosidase (SA-βGAL) activity, and upregulation of p53 and p21 (without p16 expression), cell-cycle arrest, reduced clonogenicity, and some moderated changes in stemness properties. Importantly, almost all of these features were found in MSC isolated from B-ALL patients. These alterations rendered B-ALL cells susceptible to the chemotherapeutic agent dexamethasone. The senescent process seems to be transient since when leukemic cells are removed, normal MSC morphology is re-established, SA-βGAL expression is diminished, and MSC are capable of re-entering cell cycle. In addition, few cells showed low γH2AX phosphorylation that was reduced to basal levels upon cultivation. The reversibility of the senescent process in MSC must impinge important biological and clinical significance depending on cell interactions in the bone marrow at different stages of disease progression in B-ALL. 相似文献
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粒子群算法因其形式比较简洁,参数设置灵活,操作简便易行,并且能够快速收敛,从而引起广泛关注。但是传统的粒子群算法也有缺陷:收敛速度慢以及容易陷入局部最优等。针对这些问题,本文借鉴小生境的方法,在进化初始阶段,对种群进行划分,将初始种群分为子种群,对不同的子种群进行不同的变异策略;在进化过程中,针对不同的子种群,设置不同的惯性权重因子ω,用来增强全局搜索能力与局部搜索能力。实验结果表明,本文提出的算法较传统的粒子群算法具有较快的收敛性以及找寻的全局最优解更接近真实解集,收敛精度比较高。 相似文献
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Under the circumstance of perceptual consumption, it is still challenging to grasp consumer's emotions and demands due to the large search space, diversified preferences, and easy fatigue of consumers. To reduce user fatigue and enlarge search space, a novel method was presented to design and optimize the pattern of yarn-dyed plaid fabric using the isolation niche genetic algorithm and rough set theory. Each pattern was encoded as a chromosome based on the real number code. The population was initialized and evolved using INGA to maintain the diversity. The rough set theory was adopted as the fitness function of isolation niche genetic algorithm to extract the consumer's demands. After multiple evolutions, a large set of practical patterns of the yarn-dyed plaid fabric are obtained. Experiments were carried out by 24 testers of different ages and genders. The results prove that the proposed method based on the isolation niche genetic algorithm and rough set theory is feasible and effective, supplying references to the designer. 相似文献
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目的在消费人群需求层次日趋多样化、差异化的前提下,借用"小众化"消费群体需求概念,提出目标用户消费心态需求特征,针对目标用户需求特征进行满足需求的有效产品设计方法。方法通过小众群体需求特征的提炼,得出受小众用户青睐的个性化、休闲、愉悦、多样化、小批量、体验感等要素。基于要素构筑产品设计表现信息,提出突出设计新意、凸显用户体验、使用功能集成、体现个人定制等方法,并在每一方法中引用实际的案例验证该方法是否有效,从而探索如何把对目标用户研究结果转化为有效、具有美感、有针对性的产品设计手段。结论该方法通过消费心态来描述目标用户需求及特征,有效帮助产品设计定位,从而构建产品设计信息。能够解决在产品设计中个性化、情感化、多样化等问题,有针对性地表现用户符合认知、突出时尚、个性的特点。 相似文献
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Jennie L. Pearce Karen E. Smokorowski Jaclyn Brush Evan Timusk Jerome Marty Michael Power 《河流研究与利用》2019,35(9):1575-1589
Long‐term monitoring of the food web of a regulated hydropeaking river was conducted to assess if previously documented effects of changing ramping rates (RRs) were maintained with the addition of 6 years of data. Using carbon and nitrogen stable isotope analyses, we hypothesized that: (1) macroinvertebrates and fish inhabiting areas below peaking hydrodams would be higher in δ15N and lower in δ13C due to increased flow velocity and the influence of light respired dissolved inorganic carbon, relative to those sampled from areas with a natural flow regime; (2) the increase in δ15N of macroinvertebrates would lead a shorter food web length in the regulated river, but δ13C and niche width would be similar between the restricted and unrestricted RR periods (i.e., the BACI analysis); and (3) isotopic metrics (e.g., δ13C, δ15N, niche width [SEAB], and food chain length [Δ15N]) would correlate with variations in flow characteristics through time. Consistent with previous analysis conducted over a shorter time period, a shift toward higher δ15N values was observed for both fish and invertebrates, but, contrarily, only invertebrates (not fish) had a lower δ13C value downstream of the dam. Over the long term, the before‐after‐control‐impact analysis found no effect of RRs on any of the food web metrics, implying that the change in operation did not affect the river food web. However, analysis of the time series data indicated that flow metrics and trophic metrics were often correlated, including a negative effect of RR (invertebrates) and discharge (fish) on food chain length. This study illustrates the difficulty in detecting changes in food web structure and function under changing flow regime influenced by natural and anthropogenic effects. As such, this study highlights the need for considering large spatial and temporal scales to differentiate between confounding effects of climate, natural variability, and altered flow regimes on food webs in regulated rivers. 相似文献