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Managing Software Testing Technical Debt Using Evolutionary Algorithms 被引量:1
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作者 Muhammad Abid Jamil Mohamed K.Nour 《Computers, Materials & Continua》 SCIE EI 2022年第10期735-747,共13页
Technical debt(TD)happens when project teams carry out technical decisions in favor of a short-term goal(s)in their projects,whether deliberately or unknowingly.TD must be properly managed to guarantee that its negati... Technical debt(TD)happens when project teams carry out technical decisions in favor of a short-term goal(s)in their projects,whether deliberately or unknowingly.TD must be properly managed to guarantee that its negative implications do not outweigh its advantages.A lot of research has been conducted to show that TD has evolved into a common problem with considerable financial burden.Test technical debt is the technical debt aspect of testing(or test debt).Test debt is a relatively new concept that has piqued the curiosity of the software industry in recent years.In this article,we assume that the organization selects the testing artifacts at the start of every sprint.Implementing the latest features in consideration of expected business value and repaying technical debt are among candidate tasks in terms of the testing process(test cases increments).To gain the maximum benefit for the organization in terms of software testing optimization,there is a need to select the artifacts(i.e.,test cases)with maximum feature coverage within the available resources.The management of testing optimization for large projects is complicated and can also be treated as a multi-objective problem that entails a trade-off between the agile software’s short-term and long-term value.In this article,we implement a multi-objective indicatorbased evolutionary algorithm(IBEA)for fixing such optimization issues.The capability of the algorithm is evidenced by adding it to a real case study of a university registration process. 展开更多
关键词 Technical debt software testing optimization large scale agile projects evolutionary algorithms multiobjective optimization indicatorbased evolutionary algorithm(IBEA) pareto front
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Empirical Study of Hybrid Optimization Strategy for Evolutionary Testing
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作者 Chunling Hu Bixin Li +1 位作者 Xiaofeng Wang Gang Lv 《国际计算机前沿大会会议论文集》 2019年第2期51-53,共3页
Evolutionary testing (ET) is an effective test case generation technique which uses some meta-heuristic search algorithm, especially genetic algorithm, to generate test case automatically. However, the population prem... Evolutionary testing (ET) is an effective test case generation technique which uses some meta-heuristic search algorithm, especially genetic algorithm, to generate test case automatically. However, the population prematurity problem may decrease the performance of ET. In this paper, a hybrid optimization strategy is proposed based on extended cataclysm which integrates both static configuration strategies and dynamic optimization strategy. Dynamic optimization strategy included the optimization of initial population and the dynamic population optimization based on extended cataclysm, where the diversity of population was monitored during the evolution process of ET, and once the population prematurity was detected, extended cataclysm operation was used to renew the diversity of the population. Experimental results show that the hybrid optimization strategy can improve the performance of ET. 展开更多
关键词 evolutionary testing POPULATION PREMATURITY EXTENDED cataclysm DIVERSITY measurement
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Effectiveness Assessment of the Search-Based Statistical Structural Testing
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作者 Yang Shi Xiaoyu Song +1 位作者 Marek Perkowski Fu Li 《Computers, Materials & Continua》 SCIE EI 2022年第2期2191-2207,共17页
Search-based statistical structural testing(SBSST)is a promising technique that uses automated search to construct input distributions for statistical structural testing.It has been proved that a simple search algorit... Search-based statistical structural testing(SBSST)is a promising technique that uses automated search to construct input distributions for statistical structural testing.It has been proved that a simple search algorithm,for example,the hill-climber is able to optimize an input distribution.However,due to the noisy fitness estimation of the minimum triggering probability among all cover elements(Tri-Low-Bound),the existing approach does not show a satisfactory efficiency.Constructing input distributions to satisfy the Tri-Low-Bound criterion requires an extensive computation time.Tri-Low-Bound is considered a strong criterion,and it is demonstrated to sustain a high fault-detecting ability.This article tries to answer the following question:if we use a relaxed constraint that significantly reduces the time consumption on search,can the optimized input distribution still be effective in faultdetecting ability?In this article,we propose a type of criterion called fairnessenhanced-sum-of-triggering-probability(p-L1-Max).The criterion utilizes the sum of triggering probabilities as the fitness value and leverages a parameter p to adjust the uniformness of test data generation.We conducted extensive experiments to compare the computation time and the fault-detecting ability between the two criteria.The result shows that the 1.0-L1-Max criterion has the highest efficiency,and it is more practical to use than the Tri-Low-Bound criterion.To measure a criterion’s fault-detecting ability,we introduce a definition of expected faults found in the effective test set size region.To measure the effective test set size region,we present a theoretical analysis of the expected faults found with respect to various test set sizes and use the uniform distribution as a baseline to derive the effective test set size region’s definition. 展开更多
关键词 Statistical structural testing evolutionary algorithms OPTIMIZATION coverage criteria
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Determination of Total Flavonoids in Acanthopanax senticosus(Rupr. et Maxim.) Harms by Enzymolysis and Its Technological Optimization
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作者 Li Xinzhi Wang Yudan +4 位作者 Wang Meiliang Liu Tianyang Gao Ruihua Qiu Youwen Zhang Shunjie 《Journal of Northeast Agricultural University(English Edition)》 CAS 2024年第1期53-60,共8页
In order to optimize the ultrasonic extraction technique for the total flavonoid of leaf yellows plus, the contents of 21 leaf yellows plus total flavonoid from four regions in Heilongjiang Province were comparatively... In order to optimize the ultrasonic extraction technique for the total flavonoid of leaf yellows plus, the contents of 21 leaf yellows plus total flavonoid from four regions in Heilongjiang Province were comparatively analyzed. The ultrasonic extraction technology was optimized by Box-Behnken response surface method, and the total flavonoid content of 21 kinds of Acanthopanax senticosus(Rupr. et Maxim.) Harms from different producing areas were analyzed by cluster analysis. The optimal process conditions were determined as ultrasonic time 30 min, solid-liquid ratio 1 : 12 and ultrasonic power 250 W, and the average yield of the total flavonoid was 1.453 mg·g^ (-1). By optimizing the ultrasonic-assisted extraction method, the total flavonoid content from different producing areas was compared in the experiment, which provided certain data support for the optimization of the extraction process in the future and laid a certain theoretical foundation for the quality analysis of Chinese medicinal materials. 展开更多
关键词 Acanthopanax senticosus(Rupr.et Maxim.)Harms total flavonoid Box-Behnken response surface test ultrasonic-assisted extraction
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下生殖道感染和IVF-ET结局关系探讨 被引量:2
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作者 王颖 梁思群 +2 位作者 王长娟 乔杰 王丽娜 《生殖与避孕》 CAS CSCD 北大核心 2007年第11期704-709,共6页
目的:探讨宫颈感染、阴道感染与IVF-ET结局的关系。方法:回顾性分析2005年在我院生殖医学中心就诊的798例因不孕症行IVF-ET患者的液基薄层细胞检测(TCT)结果、阴道分泌物检查、HPV测定以及阴道镜和宫颈活检情况与IVF-ET过程中获卵数、... 目的:探讨宫颈感染、阴道感染与IVF-ET结局的关系。方法:回顾性分析2005年在我院生殖医学中心就诊的798例因不孕症行IVF-ET患者的液基薄层细胞检测(TCT)结果、阴道分泌物检查、HPV测定以及阴道镜和宫颈活检情况与IVF-ET过程中获卵数、胚胎质量和妊娠结局的关系。结果:798例取卵周期798个,新鲜胚胎移植周期648个,胚胎解冻移植周期588个;继续妊娠278例(34.8%),异位妊娠22例(2.7%),胚胎停育及自然流产26例(3.2%)。临床检查宫颈情况以及HPV感染情况在各种不孕原因间无统计学差异。阴道炎、HPV感染、宫颈感染以及TCT结果与IVF-ET的结局无明显关系;阴道炎类型及治疗与否、HPV感染与否、宫颈感染的程度以及TCT结果与IVF-ET过程中各个临床参数无明显关系(P<0.05)。结论:下生殖道感染与不孕症的类型、病因以及IVF-ET过程中各临床参数和妊娠结局无明显关系,不建议过度治疗HPV感染和阴道炎症而延误IVF-ET的治疗。 展开更多
关键词 宫颈细胞学 IVF-et 阴道感染 薄层细胞检测(TCT)
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利用强度Pareto进化算法的多目标无功优化 被引量:21
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作者 冯士刚 艾芊 《高电压技术》 EI CAS CSCD 北大核心 2007年第9期115-119,共5页
为更好地解决电力系统多目标无功优化问题,分析了当前多目标无功优化算法存在的缺陷,首次将强度Pareto进化算法(SPEA2)应用于多目标无功优化,为真正意义上的多目标无功优化提供了依据。SPEA2是一种新型的多目标进化算法,参数设置少,收... 为更好地解决电力系统多目标无功优化问题,分析了当前多目标无功优化算法存在的缺陷,首次将强度Pareto进化算法(SPEA2)应用于多目标无功优化,为真正意义上的多目标无功优化提供了依据。SPEA2是一种新型的多目标进化算法,参数设置少,收敛速度快,寻优能力强,求得的Pareto最优解分布均匀。IEEE30节点测试系统的算例结果表明所提出的算法在多目标无功优化中具有良好的效果,为各目标之间的权衡分析提供了有效工具,是一种求解多目标无功优化问题的有效方法。 展开更多
关键词 强度Pareto进化算法 PARetO最优解 静态电压稳定裕度 多目标无功优化 电力系统 IEEE30节点测试系统
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美国专业考试机构ETS的组织定位分析与启示 被引量:1
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作者 田霖 《中国考试》 2017年第2期64-69,共6页
美国教育考试服务中心(Educational Testing Service,ETS)是全球规模最大的非营利教育测量机构。它通过提供公平有效的评估、研究及相关服务来促进全世界的教育质量与公平。ETS对组织角色进行科学定位,严格依据有关法律条款开展组织活动... 美国教育考试服务中心(Educational Testing Service,ETS)是全球规模最大的非营利教育测量机构。它通过提供公平有效的评估、研究及相关服务来促进全世界的教育质量与公平。ETS对组织角色进行科学定位,严格依据有关法律条款开展组织活动,制定测验质量管理标准体系,依托科研能力强化组织竞争优势,实施发展型组织战略,使其一直保持国际教育测量行业领导者地位,引领世界教育评估理论与技术发展趋势。ETS的组织角色定位与发展策略为我国省级教育考试机构专业化建设带来重要启示。 展开更多
关键词 考试机构 非营利组织 etS 考试测评
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基于MODIS ET数据的塔里木河干流蒸散发变化趋势 被引量:2
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作者 王丞 崔东 +1 位作者 丛振华 谢海燕 《伊犁师范学院学报(自然科学版)》 2018年第1期50-56,共7页
为探明综合治理之后塔里木河干流ET变化趋势,选择阿拉尔-大西海子河段为研究区,利用2000~2014年MODIS ET数据,借助于Mann-Kendall检验、Theil-Sen median趋势分析和R/S持续性分析等方法及空间分析技术,对研究区ET的时空变化进行了分析,... 为探明综合治理之后塔里木河干流ET变化趋势,选择阿拉尔-大西海子河段为研究区,利用2000~2014年MODIS ET数据,借助于Mann-Kendall检验、Theil-Sen median趋势分析和R/S持续性分析等方法及空间分析技术,对研究区ET的时空变化进行了分析,结果表明:1)阿拉尔-大西海子河段ET整体呈非显著减少趋势,但存在明显空间差异,阿拉尔-十四团上游段ET呈非显著增加趋势,增加速率达1.91 mm·a^(-1),十四团-大西海子的中游和下游段ET呈非显著减少趋势,减少速率分别为0.48 mm·a^(-1)和0.52 mm·a^(-1);2)整个河段ET呈现减少和增加变化趋势的区域分别约为71%和29%,但其中显著增加和显著减少的比例仅为6.08%和17.53%;3)全区85.63%的区域ET的变化速率介于-0.20~0.20 mm·a^(-1)其中66.58%为减少,19.05%为增加,空间上高速增加区域分布于上游段,高速减少的区域分布于中游段;4)持续性分析表明未来一定时期全区99.86%区域的ET仍将保持原有变化趋势,且其持续性强度沿河流方向逐步增强. 展开更多
关键词 蒸散发 MODISet 非参数检验 R/S分析 塔里木河干流
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Trends in major and minor meteorological variables and their influence on reference evapotranspiration for mid Himalayan region at east Sikkim, India 被引量:1
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作者 Shweta YADAV Proloy DEB +2 位作者 Sonu KUMAR Vanita PANDEY Pankaj Kumar PANDEY 《Journal of Mountain Science》 SCIE CSCD 2016年第2期302-315,共14页
Abstract: Estimation of evapotranspiration (ET) for mountain ecosystem is of absolute importance since it serves as an important component in balancing the hydrologic cycle. The present study evaluates the performa... Abstract: Estimation of evapotranspiration (ET) for mountain ecosystem is of absolute importance since it serves as an important component in balancing the hydrologic cycle. The present study evaluates the performance of original and location specific calibrated Hargreaves equation (HARG) with the estimates of Food and Agricultural Organization (FAO) Penman Monteith (PM) method for higher altitudes in East Sikkim, India. The results show that the uncalibrated HARG model underestimates ET0 by 0.35 mm day^-1 whereas the results are significantly improved by regional calibration of the model. In addition, this paper also presents the variability in the trajectory associated with the climatic variables with the changing climate in the study site. Non- parametric Mann-Kendall (MK) test was used to investigate and understand the mean monthly trend of eight climatic parameters including reference evapotranspiration (ET0) for the period of 1985 - 2009. Trend of ET0 was estimated for the calculations done by FAO PM equation. The outcomes of the trend analysis show significant increasing (p ≤ 0.05) trend represented by higher Z-values, through MK test, for net radiation (Rn), maximum temperature (Tmax) and minimum temperature (Train), especially in the first months of the year. Whereas, significant (0.01 ≥ p ≤0.05) decreasing trend in vapor pressure deficit (VPD) and precipitation (P) is observed throughout the year. Declining trend in sunshine duration, VPD and ET0 is found in spring (March - May) and monsoon (June - November) season. The result displays significant (0.01≤ p ≤0.05) decreasing ET0 trend between (June - December) except in July, exhibiting the positive relation with VPD followed by sunshine duration at the station. Overall, the study emphasizes the importance of trend analysis of ET0 and other climatic variables for efficient planning and managing the agricultural practices, in identifying the changes in the meteorological parameters and to accurately assess the hydrologic water balance of the hilly regions. 展开更多
关键词 Reference evapotranspiration (et0) Climatic variables Trend analysis Mann-Kendall's test Monthly variation East Sikkim hilly region
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EUETS二氧化碳价格问题研究——基于MSVAR模型 被引量:3
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作者 海小辉 《财经理论研究》 2017年第6期37-46,共10页
本文主要探讨EU ETS中的EUA现货价格与宏观经济、金融市场和能源市场之间的关系。考虑到2006年4月发生的核证排放量披露事件导致EUA现货价格的急剧下降、EU ETS的阶段性、金融危机对碳市场可能的潜在影响和碳价自身的波动性等因素,本文... 本文主要探讨EU ETS中的EUA现货价格与宏观经济、金融市场和能源市场之间的关系。考虑到2006年4月发生的核证排放量披露事件导致EUA现货价格的急剧下降、EU ETS的阶段性、金融危机对碳市场可能的潜在影响和碳价自身的波动性等因素,本文使用马尔科夫机制转移向量自回归模型(MSVAR)讨论宏观经济、金融市场和能源市场与碳价的非线性关系。通过该模型将整个样本期划分为四个机制,针对每个机制分析宏观经济、金融市场、能源市场与EUA现货价格之间的关系。实证结果发现:第一,正常状态下宏观经济、金融市场和能源市场对碳市场的影响方向上均符合预期,但都存在着滞后性。第二,在不同机制下,可能源于碳市场是新兴市场又有其独特的交易制度,造成宏观经济对碳价影响呈波动状态,金融市场对其的影响表现出不稳定性,能源市场对碳市场的影响不具有鲁棒性。第三,金融危机对碳市场的影响时间不长,但是对碳市场会起到质的改变。第四,碳市场在第一阶段快结束时期,由于本身交易制度的原因,各变量对碳市场的作用不明显。 展开更多
关键词 EU etS 碳价 MSVAR模型 bootstrap仿真检验
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探讨试管婴儿技术(IVF-ET)患者心理情况及护理效果 被引量:7
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作者 陶晶 《中国继续医学教育》 2015年第3期134-134,共1页
目的:分析实施试管婴儿技术(IVF-ET)患者的心理情况与护理的效果。方法随机选择我院2011年3月~2013年4月所收治的试管婴儿技术患者2500例,分作对照组和研究组各1250例,对照组采用常规的护理手段实施护理,研究采用健康护理手段实... 目的:分析实施试管婴儿技术(IVF-ET)患者的心理情况与护理的效果。方法随机选择我院2011年3月~2013年4月所收治的试管婴儿技术患者2500例,分作对照组和研究组各1250例,对照组采用常规的护理手段实施护理,研究采用健康护理手段实施护理,对比两组心理情况与护理的效果。结果采用不同方法护理后,研究组患者的忧郁、焦虑、躯体化及人际关系敏感心理方面的水平低于对照组,研究组妊娠终止的结局明显优于对照组,差异有明显的统计学意义(P<0.05)。结论对试管婴儿技术患者实施健康护理,能够有效的缓解患者的心理问题,提高护理效果,减少术后并发症情况,在临床上具有重要的实践意义。 展开更多
关键词 试管婴儿技术 心理护理
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理解和运用《教育与心理测试标准》——ETS的案例研究 被引量:2
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作者 Cathy Wendler Barbara Kirsh 冯采 《中国考试》 2017年第10期27-35,共9页
《教育与心理测试标准》由美国心理协会(APA)、美国教育研究协会(AERA)和美国国家教育测量协会(NCME)联合制定,美国教育考试服务中心(ETS)仿效《教育与心理测试标准》,制定了《ETS质量和公平标准》。本文介绍这两套标准的制定过程以及... 《教育与心理测试标准》由美国心理协会(APA)、美国教育研究协会(AERA)和美国国家教育测量协会(NCME)联合制定,美国教育考试服务中心(ETS)仿效《教育与心理测试标准》,制定了《ETS质量和公平标准》。本文介绍这两套标准的制定过程以及历史发展,《ETS质量和公平标准》的理念以及在ETS考试产品中的应用。 展开更多
关键词 测试标准 教育和心理测试标准 etS质量和公平标准
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Discrete Circular Distributions with Applications to Shared Orthologs of Paired Circular Genomes
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作者 Tomoaki Imoto Grace S.Shieh Kunio Shimizu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第6期1131-1149,共19页
For structural comparisons of paired prokaryotic genomes,an important topic in synthetic and evolutionary biology,the locations of shared orthologous genes(henceforth orthologs)are observed as binned data.This and oth... For structural comparisons of paired prokaryotic genomes,an important topic in synthetic and evolutionary biology,the locations of shared orthologous genes(henceforth orthologs)are observed as binned data.This and other data,e.g.,wind directions recorded at monitoring sites and intensive care unit arrival times on the 24-hour clock,are counted in binned circular arcs,thus modeling them by discrete circular distributions(DCDs)is required.We propose a novel method to construct a DCD from a base continuous circular distribution(CCD).The probability mass function is defined to take the normalized values of the probability density function at some pre-fixed equidistant points on the circle.Five families of constructed DCDs which have normalizing constants in closed form are presented.Simulation studies show that DCDs outperform the corresponding CCDs in modeling grouped(discrete)circular data,and minimum chi-square estimation outperforms maximum likelihood estimation for parameters.We apply the constructed DCDs,invariant wrapped Poisson and wrapped discrete skew Laplace to compare the structures of paired bacterial genomes.Specifically,discrete four-parameter wrapped Cauchy(nonnegative trigonometric sums)distribution models multi-modal shared orthologs in Clostridium(Sulfolobus)better than the others considered,in terms of AIC and Freedman’s goodness-of-fit test.The result that different DCDs fit the shared orthologs is consistent with the fact they belong to two kingdoms.Nevertheless,these prokaryotes have a common favored site around 70°on the unit circle;this finding is important for building synthetic prokaryotic genomes in synthetic biology.These DCDs can also be applied to other binned circular data. 展开更多
关键词 Bacterial genomes circular distribution goodness-of-fit test modeling synthetic and evolutionary biology.
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Managing Health Treatment by Optimizing Complex Lab-Developed Test Configurations: A Health Informatics Perspective
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作者 Uzma Afzal Tariq Mahmood +1 位作者 Ali Mustafa Qamar Ayaz H.Khan 《Computers, Materials & Continua》 SCIE EI 2023年第6期6251-6267,共17页
A complex Laboratory Developed Test(LDT)is a clinical test developed within a single laboratory.It is typically configured from many fea-ture constraints from clinical repositories,which are part of the existing Lab-o... A complex Laboratory Developed Test(LDT)is a clinical test developed within a single laboratory.It is typically configured from many fea-ture constraints from clinical repositories,which are part of the existing Lab-oratory Information Management System(LIMS).Although these clinical repositories are automated,support for managing patient information with test results of an LDT is also integrated within the existing LIMS.Still,the support to configure LDTs design needs to be made available even in standard LIMS packages.The manual configuration of LDTs is a complex process and can generate configuration inconsistencies because many constraints between features can remain unsatisfied.It is a risky process and can lead patients to undergo unnecessary treatments.We proposed an optimized solution(opt-LDT)based on Genetic Algorithms to automate the configuration and resolve the inconsistencies in LDTs.Opt-LDT encodes LDT configuration as an optimization problem and generates a consistent configuration that satisfies the constraints of the features.We tested and validated opt-LDT for a local secondary care hospital in a real healthcare environment.Our results,averaged over ten runs,show that opt-LDT resolves 90%of inconsistencies while taking between 6 and 6.5 s for each configuration.Moreover,positive feedback based on a subjective questionnaire from clinicians regarding the performance,acceptability,and efficiency of opt-LDT motivates us to present our results for regulatory approval. 展开更多
关键词 Artificial intelligence health informatics evolutionary algorithms genetic algorithms feature selection laboratory developed test
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Molecular Detection and Sequencing for S1 Glycoprotein Gene of Bronchitis Virus of 2016 Epidemic from Sindh and Punjab
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作者 Ahmad Umer Sultan Muhammad Danish Mehmood +4 位作者 Rameez Hassan Huma Anwar Sana Noreen Faisal Amin Sajjad Hussain 《Advances in Bioscience and Biotechnology》 2018年第12期649-660,共12页
Infectious Bronchitis (IB) is highly contagious disease of commercial poultry causing substantial economic loses by producing poor quality meat in broilers and effecting production in breeder birds. The causative agen... Infectious Bronchitis (IB) is highly contagious disease of commercial poultry causing substantial economic loses by producing poor quality meat in broilers and effecting production in breeder birds. The causative agent has been reported as most hazardous pathogen among other infectious agent even after being immunized with multi-variant strain vaccine. Currently, different strain such as H-120, 4/91 and D274 have been used extensively for immunoprophylaxis against velogenic strain across Pakistan with minimal protection reported. In current study PCR analysis was used to investigate the molecular nature of IB isolates from Punjab and Sind province of Pakistan in 2016 epidemics. Total of 100 tracheal samples were considered for virus inoculation in 10 days old chicken embryonated eggs. The IBV infected amniotic fluid was neutralized with monoclonal antisera of H-120, 4/91 and D274 strains. The IBV screened samples were subjected for RNA extraction and subsequent to PCR using type specific primer of each strain. The amplified product of 840 bp was sequenced through Sanger sequencing. On the basis of PCR results, four similar amplified products from both regions were obtained showing similarities in agarose gel electrophoresis, but they differ from each other on the basis of nucleotides sequence. Phylogenetic analysis revealed that nucleotide sequences of isolates from Karachi were similar to the IBV H-120, Mass-41 and Connecticut 46 reference strains. Whereas, isolates from the Punjab province are analogous to the Mans-2, Mans-3, 9/41(UK) but did not show significant similarity with other reference strain. Therefore, it is recommended that use of M-41 and H-120 in vaccine production could be effective measure against velogenic infectious agent in Sindh particularly in Karachi, whereas, it would be better to incorporate either of the variant GQ281656.1, AY279533.1 in vaccine because of their highest level of resemblance with genetically sequenced isolates from Lahore and its surroundings. 展开更多
关键词 Infectious BRONCHITIS VIRUS S1 GLYCOPROTEIN Polymerase Chain Reaction VIRUS NEUTRALIZATION test Molecular evolutionary Genetics Analysis
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托福考试及ETS对我国语言测试机构中介化的启示
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作者 朱雪莲 《温州职业技术学院学报》 2016年第3期81-83,88,共4页
托福考试成为目前规模最大的国际性、标准化权威外语考试之一。托福考试的成功举办归因于全球最大的教育考试和研究机构ETS。作为教育考试中介机构,ETS的宗旨、人员结构、服务等方面对我国语言测试机构中介化改革具有重要启示。为加快... 托福考试成为目前规模最大的国际性、标准化权威外语考试之一。托福考试的成功举办归因于全球最大的教育考试和研究机构ETS。作为教育考试中介机构,ETS的宗旨、人员结构、服务等方面对我国语言测试机构中介化改革具有重要启示。为加快我国语言测试社会化改革步伐,我国语言测试机构必须增强服务意识,合理组织人员结构,建立全球发展战略。 展开更多
关键词 托福考试 etS 语言测试机构 中介化
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Maintaining an Optimal Flow of Forest Products under a Carbon Market: Approximating a Pareto Set of Optimal Silvicultural Regimes for Eucalyptus fastigata
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作者 Oliver Chikumbo Thomas J. Straka 《Open Journal of Forestry》 2012年第3期138-149,共12页
A competitive co-evolutionary Multi-Objective Genetic Algorithm (cc-MOGA) was used to approximate a Pareto front of efficient silvicultural regimes for Eucalyptus fastigata. The three objectives to be maximised includ... A competitive co-evolutionary Multi-Objective Genetic Algorithm (cc-MOGA) was used to approximate a Pareto front of efficient silvicultural regimes for Eucalyptus fastigata. The three objectives to be maximised included, sawlog, pulpwood and carbon sequestration payment. Three carbon price scenarios (3CPS), i.e. NZ $25, NZ $50 and NZ $100 for a tonne of CO2 sequestered, were used to assess the impact on silvicultural regimes, against a fourth non-carbon Pareto set of efficient regimes (nonCPS), determined from a cc-MOGA with two objectives, i.e. competing sawlog and pulpwood productions. Carbon prices included in stand valuation were found to influence the silvicultural regimes by increasing the rotation length and lowering the final crop number before clearfell. However, there were no significant changes in the frequency, timing, and intensity of thinning operations amongst all the four Pareto sets of solutions. However, the 3CPS were not significantly different from each other, which meant that these silvicultural regimes were insensitive to the price of carbon. This was because maximising carbon sequestration was directly related to the biological growth rate. As such an optimal mix of frequency, intensity, and timing of thinning maintained maximum growth rate for as long as possible for any one rotation. 展开更多
关键词 OPTIMAL Control COMPetITIVE Co-evolutionary Multi-Objective Genetic Algorithm (cc-MOGA) PARetO Front Forest HOLDING Value Kruskal-Wallis test Multiple Comparison Procedure
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冲积性弯曲河道造床过程及演变机制
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作者 渠庚 杨翰林 +3 位作者 陈羿名 郑承太 胡呈维 栾华龙 《长江科学院院报》 CSCD 北大核心 2024年第8期15-22,共8页
冲积性弯曲河道独特的几何边界特征,使得弯曲河道的水沙运动特性和河床演变特性与其他类型河道显著不同。为模拟自然条件下的冲积性弯曲河道河床冲淤演变特性,采用自然模型法的理念在试验水槽中塑造出近似的弯曲河道,探究不同水沙条件... 冲积性弯曲河道独特的几何边界特征,使得弯曲河道的水沙运动特性和河床演变特性与其他类型河道显著不同。为模拟自然条件下的冲积性弯曲河道河床冲淤演变特性,采用自然模型法的理念在试验水槽中塑造出近似的弯曲河道,探究不同水沙条件对弯曲河道形成和发育过程的影响。试验表明:进口水沙循环周期长、来水来沙强度较小时,弯曲河道达到动态平衡状态所需的时间相对较短,河道形成稳定河宽也较小。弯曲河道在形成和发育过程中,河道的形态要素主要由水沙作用条件决定,在一定变化范围内,当水沙作用循环变换周期较短、来流流量较小、含沙量较大时,有利于形成弯曲度较大的河道;而当来流量较大、水位漫滩冲刷浅滩时,所塑造的弯曲河道会偏向于宽浅形断面形态。在河道弯曲程度和河道横断面形态的调整中,水沙作用变化对横断面形态塑造的作用相对较强。 展开更多
关键词 冲积性弯曲河道 造床过程 演变机制 河道形态 自然模型 模型试验
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基于CGA的MPI程序分支覆盖测试套件生成
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作者 袁剑锋 刘佳 郭建卫 《计算机技术与发展》 2024年第7期78-86,共9页
针对程序的分支覆盖测试,元启发式搜索技术已经被广泛应用于测试数据生成中。然而,当前的研究成果主要适用于串行程序。因此,为覆盖消息传递接口(Message Passing Interface,MPI)程序的分支,该文研究基于协同进化遗传算法(Co-evolutiona... 针对程序的分支覆盖测试,元启发式搜索技术已经被广泛应用于测试数据生成中。然而,当前的研究成果主要适用于串行程序。因此,为覆盖消息传递接口(Message Passing Interface,MPI)程序的分支,该文研究基于协同进化遗传算法(Co-evolutionary Genetic Algorithm,CGA)的测试套件生成方法(简称为:CGA生成法),该方法具有不受不可行分支影响的优势。首先,基于收集覆盖信息的探针,定义最小归一化分支距离,并以此设计出相应的适应度值函数;然后,使用CGA生成进化个体,并基于设计的适应度值函数,计算这些个体的适应值;最后,基于计算的适应值,选择子种群中代表个体,以构成合作种群。所提CGA生成法应用于7个基准MPI程序,并与其他多种方法进行比较。实验结果表明,CGA生成法的覆盖率通常高于其他搜索算法。 展开更多
关键词 消息传递接口程序 协同进化遗传算法 分支覆盖测试 测试套件生成 适应度值函数
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地浸采铀过程中含矿层渗透性演化的示踪试验
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作者 王伟豪 刘金辉 +4 位作者 阳奕汉 王如意 梁大业 闫学锐 何挺 《有色金属(冶炼部分)》 CAS 北大核心 2024年第2期72-82,共11页
铀资源既是核军工基石又是核电发展的粮仓,在当前复杂国际形势与大力发展核电的时代,更是一种不可或缺的重要资源。随着内蒙古巴彦乌拉铀矿地浸采铀的运行,矿层堵塞、铀浸出量下降等问题逐渐浮现。为探明地浸采铀过程中含矿层渗透性的... 铀资源既是核军工基石又是核电发展的粮仓,在当前复杂国际形势与大力发展核电的时代,更是一种不可或缺的重要资源。随着内蒙古巴彦乌拉铀矿地浸采铀的运行,矿层堵塞、铀浸出量下降等问题逐渐浮现。为探明地浸采铀过程中含矿层渗透性的演化特征,在巴彦乌拉铀矿床C10采区某试验单元开展了井间示踪试验。试验结果表明,地浸一年后含矿层砂岩孔隙度与渗透性降低,其原因与含矿层砂岩孔隙发生堵塞有关。地浸二年后各方向渗流通道溶浸液流速较地浸一年均有不同程度降低,且下降幅度相较于前一年更大。但在试验单元三个渗流方向即KZ13238-KC13036、KZ13238-KC13038和KZ13238-KC13438方向均产生了优势渗流通道。表明随着采区的运行,含矿层孔隙堵塞情况日益严重,含矿层渗透性不断降低。研究结果可以为地浸中含矿层渗透性演化特征提供示踪证据。 展开更多
关键词 地浸采铀 渗透性 演化特征 井间示踪试验
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