Context-Aware Practice Problem Recommendation Using Learners’ Skill Level Navigation Patterns

The use of programming online judges(POJs)has risen dramatically in recent years,owing to the fact that the auto-evaluation of codes during practice motivates students to learn programming.Since POJs have greater number of pro-gramming problems in their repository,learners experience information overload.Recommender systems are a common solution to information overload.Current recommender systems used in e-learning platforms are inadequate for POJ since recommendations should consider learners’current context,like learning goals and current skill level(topic knowledge and difficulty level).To overcome the issue,we propose a context-aware practice problem recommender system based on learners’skill level navigation patterns.Our system initially performs skill level navigation pattern mining to discover frequent skill level navigations in the POJ and tofind learners’learning goals.Collaborativefiltering(CF)and con-tent-basedfiltering approaches are employed to recommend problems in the cur-rent and next skill levels based on frequent skill level navigation patterns.The sequence similarity measure is used tofind the top k neighbors based on the sequence of problems solved by the learners.The experiment results based on the real-world POJ dataset show that our approach considering the learners’cur-rent skill level and learning goals outperforms the other approaches in practice problem recommender systems.

Correlation Between Economic Development Level and Landscape Pattern in Beijing Peri-urban Areas

With the rapid changes of demographic and socio-economic structure, various ecological and environmental problems have emerged in peri-urban areas. Studies on the correlation between socio-economic development and eco-environmental preservation are inadequate. This paper analyzes the landscape pattern of peri-urban areas to address this issue. First, it studies the differentiation of economic development levels in Beijing peri-urban areas. Then, it explores the correlation between economic development level of each town and its landscape pattern using Pearson Correlation and grade difference indices. Furthermore, it summarizes the problems within current landscape pattern. Three conclusions are drawn from the analysis: (1) on the whole, the economic de- velopment level in Beijing peri-urban areas basically matches with landscape pattern; (2) landscape contagion degree decreases with the growth of economic development level in as much as 30% of Beijing peri-urban areas. This is an irrational phenomenon accord- ing to our judgment; (3) landscape fragmentation grades in more than half of the towns are higher than their economic development grades, suggesting that attention should be paid to excessive fragmentation of land use.

Spatial variations of tidal water level and their impact on the exposure patterns of tidal land on the central Jiangsu coast

The exposed area of intertidal zone varies with tidal water level changes, If intercomparisons of satellite images are adopted as a method to determine geomorphological changes of the intertidal zone in response to accretion or erosion processes, then the effect of water level variations must be evaluated. In this study, two Landsat TM images overpassing the central Jiangsu coastal waters on 2 January and 7 March 2002, respectively, were treated by the changing detection analysis using Image Differencing and Post-classification Comparison. The simultaneous tide level data from four tide gauge stations along the coast were used for displaying the spatial variations of water levels and determining the elevations of waterlines. The results show that the spatial variations of water levels are highly significant in the central Jiangsu coastal waters. The huge differences of tidal land exposure patterns between the two imaging times are related mainly to the spatial variations of tidal water levels, which are controlled by the differences in tidal phases for different imaging times and the spatial variations of water level over the study area at each imaging time. Under complex tidal conditions, e.g., those of the central Jiangsu coastal waters, the tide-surge model should be used to eliminate effectively the effects of water level variations on remote sensing interpretation of geomorphological changes in the intertidal zone.

Gradient Analysis of Urbanization Pattern Based on Class-level Landscape Metrics for Shanghai Region

The spatial pattern of urbanization in the Shanghai metropolitan area is quantified with GIS-based land use data set and gradient analysis of landscape metrics. A number of landscape metrics were computed along a 64 km long and 6 km wide west-east transect and another 66 km long and 6 km wide south-north transect. The results of transect analysis with class-level metrics showed that the spatial pattern of urbanization could be reliably quantified using landscape metrics with a gradient analysis approach, and the location of the urbanization center could be identified precisely and consistently with multiple indices of the landscape metrics used in this study. Different land use types exhibited distinctive, but not necessarily unique,spatial signatures that were dependent on specific landscape metrics. These results seemed to characterize the urban core of the Shanghai metropolitan area rather accurately and precisely: Agriculture patches were abundant and less fragmented; the urban land use types were extensive,having many small patches and highly fragmented.

Effect of water level fluctuations on temporal-spatial patterns of foraging activities by the wintering Hooded Crane(Grus monacha)

Background:The Yangtze River floodplain provides important wintering habitats for Hooded Cranes(Grus monacha) in China.Fluctuations in the water level change foraging habitat and food availability,affecting their temporal-spatial patterns of foraging activities.It is of considerable importance to investigate the effect of these fluctuations on food availability for wintering Hooded Cranes and their foraging response to these changes.Understanding their behavior patterns is beneficial in protecting the wintering crane population and restoring their wintering habitats.Methods:A field survey of the winter behavior of cranes was carried out at Shengjin Lake from November in 2013 to April in 2014.Habitat variables,as well as the spatial distribution and behavior patterns of wintering cranes at their foraging sites during five stages of water level fluctuation were collected.Based on this data we analyzed the relationship of foraging behavior relative to water level fluctuations and habitat types.Results:The foraging habitats used by Hooded Cranes varied at the different water level stages.As the water level decreased,the use of meadows and mudflats increased.When the water dropped to its lowest level,the use by the Hooded Crane in the mudflats reached a peak.There were statistically significant differences in time budget in the three types of habitats over the five stages of the water level.In the mudflats,the foraging behavior and maintenance behavior varied significantly with the water level,while the alert behavior showed little variation.Analysis of a generalized linear model showed that the five water level stages and three habitat types had a significant effect on foraging behavior,while the combined effect of these two variables was significant on the foraging time budget and the length of foraging activity of the Hooded Crane.Conclusions:With the decrease in the water level,the use of mudflats by Hooded Cranes increased correspondingly.Food availability in different habitats was affected by changes in the water level.The Hooded Crane adjusted its foraging patterns and made full use of the three available types of habitat in order to acquire enough food in response to fluctuations in the water level.

Influence of Family Status on the Dietary Patterns and Nutritional Levels of Children

A diversity of socio economic and cultural factors contributes towards maintenance and changes in dietary patterns of people. Therefore People around the world have adapted different types of dietary patterns for their survival. Aim of this study was to investigate the most relevant factors influencing human dietary patterns. Sample for the study was selected by using the Stratified sampling technique, which consists of 390 families residing around the Abatenna estate, Bandarawela municipal council, Sri Lanka. Principal component analysis techniques and correlation analysis were employed to identify the most relevant factors which affect human dietary patterns. Results of the study indicate that socio economic conditions, monthly income, number of children in a family, dietary patterns and weight-related behaviors are highly co-related with each other. These findings suggest that education and awareness programs on nutrition should target low income groups to enhance their knowledge on dietary patterns.

Spatial Pattern and Influencing Factor of County-level Industrial Development in Liaoning Province of China

County-level industrial development and structure upgrade is one of the most important issues of revitaliz- ing old industrial base of China. After the cluster analysis on GDP per capita and GDP per area of each county in Liaoning Province, this paper finds the similarity of population size, land use intensity, and economic development of each county. Location quotient reflects the specialization intensity of industries in each county, and it also reflects the spatial differences of county-level industrial development. Economic development level is higher in the southeast than in the northwest of Liaoning, and the industry driving effect on county-level economy is apparent. The main influenc- ing factors include location, industrial foundation and economic system reform, capital input level, knowledge and technology dissemination, conditions of domestic and overseas markets, population and labor force transfer. Industri- alization is an important approach to urbanization for the counties in Liaoning Province. The proportion of agriculture is much higher in the northwest than in the southeast of Liaoning, so it will be take longer time for counties in the northwest of Liaoning to make industrialization, urbanization and modernization.

Establish Green Industry System,Improve the Comprehensive Utilization Level of Salt Lake Resources,and Create A New Pattern of Green Sustainable Development in Qaidam Basin

Qaidam Basin in Qinghai Province has rich multiple complex resources with salt lakes as the core.These resources form a special condition for the development of green economy,having rare and particular nature.The

计划行为理论下的追踪护理模式对高脂血症患者血脂水平及自我管理的影响

目的探讨计划行为理论下的追踪护理模式对高脂血症患者血脂水平及自我管理的影响。方法选取2022年1—12月郑州大学第一附属医院94例高脂血症患者,采用随机抽签法分为对照组(47例)、试验组(47例),对照组接受常规护理,试验组在此基础上实施计划行为理论下的追踪护理模式。比较两组疾病知识掌握情况、用药依从性[服药依从性量表(MMAS-8)]及干预前后血脂水平[胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)]、健康信念[健康信念模型量表(CHBMS)]、自我管理能力[成年人健康自我管理能力测评量表(AHSMSRS)]、健康行为[健康促进生活方式量表(HPLP-Ⅱ)]、心理状态[正性与负性情绪量表(PANAS)]、生活质量[世界卫生组织生活质量测定量表简表(WHOQOL-BREF)]。结果试验组疾病知识掌握率(95.74%)高于对照组(80.85%)(P<0.05);试验组用药依从率(100.00%)高于对照组(85.11%)(P<0.05);干预6个月后试验组TC、TG、LDL-C、HDL-C水平优于对照组(P<0.05);试验组干预6个月后CHBMS、AHSMSRS、HPLP-Ⅱ、WHOQOL-BREF评分均高于对照组(P<0.05);与对照组比较,干预6个月后试验组PANAS-正性评分较高,PANAS-负性评分较低(P<0.05)。结论计划行为理论下的追踪护理模式可提升高脂血症患者自我管理能力,提高其用药依从性,改善其血脂水平,提高生活质量水平。

谋开放新篇 育强国优师--《教育部关于实施国家优秀中小学教师培养计划的意见》解读

2023年7月教育部制定了国家优秀中小学教师培养计划(以下简称“国优计划”),旨在以“双一流”建设高校为依托,选拔培养专业成绩优秀且乐教适教的理工类学科人才,从而为基础教育事业培养和输送高质量的优秀教师。“国优计划”的出台,一方面是对教师教育历史政策实践,即推动教师教育向高质量发展模式转变,以及健全以开放、协同、联动为主要特点的现代教师教育体系的继承与延续;另一方面是为推动新时代教育强国、科技强国、人才强国建设和契合基础教育发展新形势所制定的创新发展路径,即构建多主体联动,贯通本研、职前职后一体化培养模式,实现“优秀人才”向“优秀教师”转化,切实解决教师队伍建设中存在的学科结构不均衡、培养层次不高等方面的问题,从源头上强化拔尖创新人才的培养。为此,对“国优计划”的政策实施路径提出以下建议:促进政策主体的外部行动协同与内部治理优化;规范研制人才选拔标准与培养方案;建立和健全面向政策实施的专业评估与跟踪监测机制;建立与政策相配套的培训与试点经验交流机制。

美国科技创新水平时空格局演变与影响因素

在全球科技竞争愈演愈烈的今天,科技创新已成为国际竞争力的核心组成部分。在中美科技摩擦不断升级的背景下,深入研究美国的科技创新水平时空格局演变对于把握世界科技创新的发展水平和特点,以及促进中国科技创新实力的提升具有重要意义。本研究以美国专利发表量等数据为基础,分析2000-2022年美国科技创新的演化规律及影响因素。发现美国科技创新水平持续增长,尽管受到经济危机、政策变化等影响,但整体稳健发展。同时,东西海岸地区创新活动集中,中部地区科技创新水平相对较低。此外,美国科技创新的空间格局逐渐向西移动,集聚度增强。这些发现为深化中国科技创新中心布局和发展战略提供了重要启示。中国应重视区域科技创新的集聚特征,推动创新带动效应;加强科技创新政策法规完善,吸引社会资本投入科技创新;同时,因地制宜培育科技创新高地,发挥科研机构集聚区优势,促进科技实力提升。

基于改进遗传算法的传声器随机阵列优化设计

针对传声器规则阵列因均匀采样间隔导致的空域混淆问题,提出一种基于改进遗传算法的传声器随机阵列优化设计方法。经过仿真分析,优化后24元随机阵列在保持主瓣性能的同时,有效抑制了旁瓣的增益。与均匀阵列相比,采用设计的遗传算法对阵列布局进行优化设计后可获得更好的旁瓣抑制和阵列增益。

新发展格局下扩大城市消费需求能否促进FDI流入?——基于长三角地区的实证研究

文章基于2011—2020年长三角地区41个城市面板数据,运用双向固定模型实证分析消费需求提升对FDI流入的影响及作用机制。研究发现:消费需求提升对FDI流入具有显著的正效应,但该正效应在经济发展水平较高城市、长三角城市群城市、生产型城市以及高水平消费需求城市中更为显著,且消费需求提升有助于促进更高质量的FDI流入;产业结构升级和信贷规模扩大在消费需求提升与FDI流入之间存在部分中介效应;消费需求与FDI具有显著的空间集聚特征,消费需求提升能够促进本市及相邻城市FDI流入。本研究对加快构建新发展格局、推进高水平对外开放具有重要的现实意义。

鄂尔多斯盆地奥陶系马家沟组四段优质白云岩储层发育特征及成因机制

鄂尔多斯盆地米探1井在奥陶系马家沟组四段(以下简称马四段)白云岩获得天然气勘探新发现,展示出马四段良好的天然气勘探前景,但马四段白云岩储层发育特征及其分布规律不清,制约了该层系下一步的天然气勘探部署。为此,基于岩心、薄片、工业CT、U-Pb定年、物性分析及地球化学特征等资料,系统研究了马四段白云岩储层发育特征及成因机制,并预测了该盆地白云岩储层分布和天然气有利勘探区带。研究结果表明:(1)马四段主要发育丘滩相白云岩储层和斑状白云岩储层,其中丘滩相白云岩储层岩性为砂砾屑白云岩、细—中晶白云岩、粉—细晶白云岩和叠层石白云岩,斑状白云岩储层岩性为斑状粉—细晶白云岩、斑状粉晶白云岩和斑状灰质白云岩。(2)丘滩相白云岩储层储集空间主要为晶间(溶)孔,含少量溶蚀孔洞、残余粒间孔和微裂缝,平均孔隙度为5.06%;斑状白云岩储层储集空间以晶间孔为主,含少量晶间溶孔和微裂缝,平均孔隙度为2.46%。(3)丘滩相白云岩储层发育主要受微生物丘和颗粒滩控制,并经历了准同生白云石化作用和埋藏白云石化作用的改造,斑状白云岩储层发育主要受生物扰动作用、准同生白云石化作用和埋藏白云石化作用控制。(4)构造古地理格局和海平面升降变化共同控制了丘滩体发育、生物扰动作用程度和白云石化流体的形成。结论认为,马四段优质白云岩储层主要沿中央古隆起和神木—志丹低隆起规模分布,其中神木—志丹低隆起马四段白云岩储层位于岩性相变带上,其储盖配置关系好,是天然气富集区,预测有利区储层面积18 000 km^(2)。

1978—2020年中国台风灾害灾情时空分布格局及影响因素分析

为探究中国台风灾害影响和灾情的时空分布及演化规律,基于县域经济社会和灾情统计数据、历史台风风雨数据、高精度地形数据等资料,以县级行政区为空间单元,采用时序统计分析法、重心模型、地理探测器、空间相关分析、地理加权回归等方法,对1978—2020年中国台风灾害灾情的时空分布格局及影响因素进行分析,结果显示:1)台风灾害造成的死亡失踪人口、倒损房屋数量和每百万人口死亡失踪率、直接经济损失占GDP的比重均呈下降趋势,防灾减灾工作取得显著成效;2)台风灾害灾情重心随沿海地区经济发展南移,灾害影响呈现沿海地区减轻、内陆地区加重的特征;3)台风引发的风雨是灾情的主要驱动因素,地形因素是造成人员死亡失踪和农作物损失的驱动因素之一;4)浙江闽北、粤西桂东两大区域灾情集聚特征显著,与台风活动规律和经济发展水平密切相关;5)局部地区生产总值与灾情呈负相关关系,反映经济社会发展对防灾减灾能力的促进作用。

英国A-level考试制度:实践模式、发展困境及改革路向

A-Level证书考试的实施是英国证书型大学入学考试制度确立的标志,既是英国教育的"黄金标准",亦是诸多英语授课大学招收新生的入学准则。英国自1951年实施A-level考试制度以来历经多次变革形成了较为完备的考试体系。然而,随着实践的深入,英国A-level入学考试逐步陷入应试的泥潭,严重影响其社会认可度和选拔功能的发挥,没能为中学生向大学过渡做好充足准备。因此,英国政府借改革契机调整考纲要求、转变评价机制、变更考试结构,为A-level入学考试制度发展寻找改良路径。英国A-level考试制度在转变培养模式、增强甄选效能、助力高大衔接方面所做的努力对我国高考制度改革的反观与思考不无裨益。

基于网格空间团的多级同位模式挖掘方法

针对传统的多级同位模式挖掘方法未考虑到实际数据分布的网格特性,且从全局到区域的多级模式挖掘框架会导致算法效率低下的问题,提出逆向挖掘多级同位模式的新框架.先挖掘区域同位模式,再由区域同位模式推导出全局同位模式,提出有效的剪枝策略提高挖掘效率.考虑真实数据集中数据分布的网格特性,定义实例间的网格邻近关系,提出网格空间团及计算网格空间团的新颖方法.在区域划分阶段,提出基于自适应网格密度峰值聚类的区域划分方法,基于2阶网格空间团的网格相似性来分配簇.在合成和实际数据集上进行大量的实验,验证了提出方法的有效性、高效性和可扩展性,在真实数据集上的剪枝率可以达到78%.

和阳消瘿汤联合优甲乐治疗脾气亏虚型桥本甲状腺炎疗效及对甲状腺激素、甲状腺自身抗体水平的影响

目的:观察和阳消瘿汤联合优甲乐治疗脾气亏虚型桥本甲状腺炎的疗效及对甲状腺激素、甲状腺自身抗体水平的影响。方法:选取2020年5月~2022年5月期间于我院接受治疗的脾气亏虚型桥本甲状腺炎患者114例为研究对象,按照随机数字表法分为观察组与对照组,其中57例对照组患者给予优甲乐治疗,57例观察组患者在以上对照组基础上给予和阳消瘿汤。比较两组治疗前后甲状腺激素[游离三碘甲状腺原氨酸(FT_(3))、游离甲状腺素(FT_(4))、促甲状腺激素(TSH)]、甲状腺自身抗体水平[抗甲状腺球蛋白抗体(TG-Ab)、甲状腺过氧化物酶抗体(TPO-Ab)]及中医证候积分的变化,并对其疗效及安全性进行客观评价。结果:治疗前两组各项指标比较无明显差异(P>0.05),治疗后TG-Ab、TPO-Ab、TSH及中医证候积分均降低(P<0.05),FT_(3)、FT_(4)均升高(P<0.05),且治疗后观察组TG-Ab、TPO-Ab、TSH、中医证候积分低于对照组(P<0.05),FT_(3)、FT_(4)高于对照组,差异有统计学意义(P<0.05);观察组总有效率为91.23%,明显高于对照组的71.93%(P<0.05),但两组不良事件发生率相比差异无统计学意义(P>0.05)。结论:和阳消瘿汤联合优甲乐治疗脾气亏虚型桥本甲状腺炎,与单纯优甲乐治疗相比,在调节甲状腺激素、降低自身抗体水平、纠正临床症状上优势明显,且疗效及安全性可靠。

特发性脊柱侧弯患者步行生物力学特征:三维运动捕捉的横断面分析

背景:脊柱侧弯的生物力学分析病例数量有限,仅限于对脊柱或下肢独立进行生物力学分析,缺乏对人体多维度整体的评估,难以反映躯干与下肢在日常活动中的运动关系,不利于综合指导临床治疗。目的:通过测量脊柱侧弯患者在步行活动中的脊柱运动学,研究脊柱不同节段及下肢运动学/动力学在步态活动中的关系,以全方位多层次评估脊柱侧弯患者与正常人群在生物力学的差异,为临床防治脊柱侧弯提供循证依据。方法:此研究为一项横断面研究,于2020年7月至2021年6月,在福州大学城、福建中医药大学附属康复医院纳入脊柱侧弯患者28例及同年龄段正常人28例。采用三维运动捕捉系统以100 Hz的采样频率捕捉步态的运动学数据,2块测力台(AMTI 400600,采样频率1500 Hz)嵌于长10 m(数据采集有效长度为4 m),宽2.4 m平地走道采集动力学数据。比较两组受试者执行平地步行时步态时空参数,运动学及动力学参数的差异。所有受试者在纳入后立即接受全脊柱X射线片测量比较两组差异。结果与结论:(1)脊柱侧弯患者肩胛带-躯干相对旋转活动度、胸廓-骨盆相对旋转活动度较正常组小(P<0.05),骨盆旋转活动度相较正常组大(P<0.05)。(2)脊柱侧弯患者髋、膝关节屈伸活动度,髋关节凹凸侧屈伸峰力矩、地反力凸侧内外向峰值较正常组小(P<0.05)。(3)脊柱侧弯患者的膝关节屈伸活动度非对称性指数、肩胛带-躯干相对旋转活动度非对称性指数、胸廓-骨盆相对旋转活动度非对称性指数较正常组大(P<0.05)。(4)上述结果证实,脊柱侧弯患者在平地行走时肩胛带-胸廓-骨盆之间僵硬的运动模式,髋膝关节屈伸活动度减少,髋关节双侧屈伸力矩峰值及地反力凸侧内外向峰值降低。这些特征可以作为康复评估及治疗方案制定的依据。

百米级均质土坝坝体排水型式研究

坝体排水设计是土石坝工程设计中重要的工作之一。合理布置坝体排水型式、排水高程和范围,可有效降低坝体浸润线,控制坝体渗流,增加下游坝坡稳定,防止发生渗透破坏。目前国内已建坝高超过70 m的均质土坝坝体排水设计仍缺少成功的工程经验。为了解决坝内排水型式设计不尽合理、排水方案设计存在缺陷等问题,依托某在建工程,对均质土坝坝体内不同高程、不同位置拟定不同排水型式组合,通过数值仿真分析,研究排水体对坝体浸润线以及坝坡稳定的影响,提出了适合百米级均质土坝的最佳排水型式(竖向排水+水平排水+棱体排水)。结果表明:对于大坝下游常水位较高的百米级均质土坝,竖向排水+水平排水+棱体排水可以做为最佳的排水型式,且竖向排水结构设置在均质土坝坝体中下游,且做成向上游倾斜的形式,考虑施工质量,向上游倾斜的坡度以1∶0.5为宜,但对于此种组合排水,大坝渗透各向异性k_(x)/k_(z)的适用范围需结合具体工程进行计算分析。研究成果可为百米级均质土坝排水设计提供参考和借鉴作用。