三元树上非对称马氏链场的强大数定律

定义了一类三元树上非对称马尔可夫链场,利用鞅方法构造鞅,根据Doob鞅收敛定理和一些特殊的不等式以及近年来研究概率论强极限定理的新方法,研究了三元树上非对称马尔可夫链场的强极限定理以及关于状态和状态序偶出现频率的强大数定理,得到了三元树上非对称马尔可夫链场的局部收敛定理以及关于状态和状态序偶出现频率的强大数定理,将三元树上对称马氏链场中的相关结果推广到了三元树上非对称马氏链场中.

新昌小将林场兽类初步研究

1996年4～5月，对新昌县小将林场的各类进行了调全，计有各类31神，隶属6目13料，其中东洋界种24种，占77．42%；古北界种7种，占22。58％，分析了啮齿类的种类、捕获季、生态分布、性比及数量变动趋势，对啮齿类群落的多样性和生物量进行了测定，对林木鼠害的发生进行预测。

杨树三倍体育种的研究现状

杨树三倍体培育主要有 4种方法 :选育天然三倍体 ;筛选天然未减数的 2n花粉人工授粉 ;四倍体与二倍体杂交 ;化学物理诱导。选育天然三倍体是比较简单的方法 ,但可供选择的数量有限。用天然 2n花粉杂交获得三倍体 ,具有偶然性、多变性的特点 ,且因 2n花粉比率较低 ,利用比较被动 ,但天然 2n花粉活力强 ,三倍体得率高。四倍体与二倍体杂交获得三倍体的方法具有较强的主动性 ,但要先得到四倍体 ,增加了育种难度及年限 ,在没有可供利用的四倍体的情况下 ,只能作为一种倍性育种的辅助途径。化学物理诱导获得三倍体具有机动灵活的特点 ,是一种获得三倍体最有效的途径。杨树三倍体育种要取得突破性进展 ,必须加强细胞学 ,尤其是染色体制片技术的研究。

Data-driven methods for predicting the representative temperature of bridge cable based on limited measured data

Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and maintenance of cable-stayed bridges.However,the representative temperatures of stayed cables are not specified in the existing design codes.To address this issue,this study investigates the distribution of the cable temperature and determinates its representative temperature.First,an experimental investigation,spanning over a period of one year,was carried out near the bridge site to obtain the temperature data.According to the statistical analysis of the measured data,it reveals that the temperature distribution is generally uniform along the cable cross-section without significant temperature gradient.Then,based on the limited data,the Monte Carlo,the gradient boosted regression trees(GBRT),and univariate linear regression(ULR)methods are employed to predict the cable’s representative temperature throughout the service life.These methods effectively overcome the limitations of insufficient monitoring data and accurately predict the representative temperature of the cables.However,each method has its own advantages and limitations in terms of applicability and accuracy.A comprehensive evaluation of the performance of these methods is conducted,and practical recommendations are provided for their application.The proposed methods and representative temperatures provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges.

基于RTF的高光谱图像去噪方法

高光谱数据中包含丰富的光谱和空间上下文信息。早期的高光谱图像去噪方法是单波段的、仅利用了高光谱数据的空间上下文信息。近年来提出的一些去噪方法综合利用了光谱和空间上下文信息,但是在对大尺度和全局上下文信息建模以及模型与图像内容自适应等方面存在局限,导致去噪结果出现过平滑的现象。针对上述问题,提出了一种基于回归树场的高光谱图像去噪方法：首先选择需要处理的高光谱波段;然后构建基于回归树场的高光谱去噪模型;最后利用基于特定代价函数的模型训练方法同时得到模型的结构和参数、输出去噪后的图像。实验结果表明,该方法能够充分利用高光谱数据的光谱和空间上下文信息,在有效去除噪声的同时很好地保存了图像中的重要细节,与BM3D和CRF相比,其PSNR提高了0.8-1.1 dB。

基于均值场计算树的Ising图模型消息族传播算法

提出基于均值场计算树的Ising图模型消息族传播算法.首先定义Ising图模型均值场计算树和均值场剪枝计算树概念来描述Ising图模型均值场推理方法的迭代计算过程.然后基于均值场计算树设计Ising图模型消息族传播算法,指出沿着计算树自底向上逐层进行消息族传播,可计算根节点变量的边缘概率分布族.同时证明基于均值场剪枝计算树的消息族传播算法可计算出变量边缘概率分布的界,即此时的边缘概率分布族包括边缘概率分布精确值.最后通过数值实验验证消息族传播算法的有效性和边缘概率分布界的紧致性.

凝视英雄:对越自卫反击战的影视书写

对越自卫反击战打响的第二年,我刚好出生。没有经历过战争的人们对这场战争不会关注太多,但恰恰是现如今生活在和平年代的人们,在网络化和全球化的今天,更需要了解那不曾属于我们的过去,反思属于我们的今天。对于那场处在特殊年代、发生在不同地点、有着特殊的对手的特殊战争,30多年以来全世界产生多种对于那场战争的英雄书写。30多年过去了,战争的阴影逐渐淡去,后来人需要在书本、电影、歌曲和舞台等方面重新凝视英雄。

当代军事电影:英雄模式的困惑——当代军事电影研究之一

没有英雄的军队是可悲的。在中国这个具有浓重的英雄膜拜风习的国度里,如何塑造英雄自然成了军事电影困惑的问题。从古至今,在中国的各种文学样式中,都记载和颂扬过无数的英雄,形形色色,无奇不有。然而,这种纷繁局面的形成仅仅是表层现象,在更深层次上,国人是用同一的思维模式和审美规范来解释英雄的,或者说。

“三口之家”协奏曲

请别误会,这“三口之家”并不是指日本电视连续剧“三口之家”。在上海电影译制厂办公楼底楼,有两个由大办公室改成的小房间,里面住着三位年青的配音演员。在他们共同拥有的那份户口上,记载着:任伟,男,26岁,西安人;沈晓谦,男,26岁,哈尔滨人;狄菲菲,女,24岁,郑州人。由于三人朝夕相处,工作、学习、生活互相帮助,朋友们戏称为“三口之家”。

“学生官”在想什么——和青年电影演员巫刚聊天

他说他最大的毛病就是爱犯盹,每晚十点左右必须就寝,否则就“盯不住”了。记得第一次去他家时,是十点多钟,这对于我来说简直是太早太早了。快到十一点时见他上眼皮跟下眼皮总是不安份,我只好告退。他很尴尬地说:“说实在地,在你来之前,我还特意喝了一杯咖啡,可还是有点盯不住了”有什么办法,自然规律无可抗拒,咱们只好改日再聊了。但不管对他还是对我,要再碰到一起能聊上一段时间的机会似乎太难。可不是吗?我后来也碰到过他两次,要么在嘈杂的大马路上,要么在厕所旁,总之都不是地方。我认识他的时候是三四年前了,那会儿他在云南前线拍摄上影厂的《战争让女人走开》,拍摄间隙就跟他聊聊,可这种机会也并不多,大多数的时候,他总是呆在一旁,而且是独自呆在墙角里的时候多。

Online Forum Post Opinion Classification Based on Tree Conditional Random Fields Model

There is a major defect when using the traditional topic-opinion model for post opinion classifications in an online forum discussion.The accuracy of the classification based on the topic-opinion model highly depends on the observable topic-opinion features aiming at the subject,while a large number of posts do not have such features in a forum.Therefore,for the most part,the accuracy is less than 78%.To solve this problem,we propose a new method to identify post opinions based on the Tree Conditional Random Fields(T-CRFs)model.First,we select the topic-opinion features of the posts and associated opinion features between posts to construct the T-CRFs model,and then we use the T-CRFs model to label the opinions of the tree-structured posts under the same topic iteratively to reach a maximum joint probability.To reduce the training cost,we design a simplified tree diagram module and some feature templates.Experimental results suggest the proposed method costs less training time and improves the accuracy by 11%.

时势的必然——“主旋律”影片三题

时至今日,“主旋律”影片已由其丰富的创作实践给我们留下了深刻的印象。我们是否可由此得出一些清晰的概念呢? 之一英雄与“反面英雄”新时期电影的发展中,有一条清晰连贯的轨迹便是英雄模式和英雄观念的演进与嬗变。这条轨迹蜿蜒延伸到一批以“革命英雄”为主人公的“主旋律”影片中,便颤发出一束耀眼的火花——“毛泽东形象”是近年来电影艺术家最为青睐的一个革命历史英雄形象。领袖观念的从神化向人化的演进,从某种意义上讲是一种社会进步和政治清明的表征。这一方面给电影艺术家提供了一次呈现艺术胆略的机会,另一方面也是检验他们艺术表现才能的一次契机。从《巍巍昆仑》、《开国大典》到今年的《开天辟地》、《毛泽东和他的儿子》、《大决战》,“

军事片何时走出“低谷”

近来无论是部队下发的计划片,还是地方影院上映的影片,军事片很少,几乎没有,即使有那么一两部,质量也不高,这不能不使广大干部战士有些失望。我们的军事片是有过辉煌历程的,早在六十年代就拍出了《英雄儿女》、《南征北战》等一些较优秀的影片,八十年代初也拍出了《高山下的花环》,《雷场相思树》、《索伦河谷的枪声》等较有影响的影片。然而今天军事片的现状却与当前整个电影行业的发展极不协调。

活跃在高原古城八年——记青海师范大学群众影评组

在大西北海拔2300米的古城西宁,活跃着一支朝气蓬勃的群众影评队伍,它就是于1983年成立的青海师范大学群众影评组。青海地处西北高原,受历史、文化因素的制约,近年来改革开放虽然取得了较为明显的成就,但社会对文化艺术的普遍鉴赏层次还比较低,看电影往往是看热闹。

Influence of CaO-based expansive agent,superabsorbent polymers and curing temperature on pore structure evolution of early-age cement paste

Cracks easily generate in concrete at early age owing to the shrinkage deformation.CaO-based expansion agent(CEA)and superabsorbent polymers(SAP)have been extensively used for the mitigation of concrete shrinkage.The macroscopic properties of concrete are highly determined by the microstructure.In this study,the influence of CEA and SAP addition on the pore structure evolution of cement paste under different curing temperatures was evaluated via low-field nuclear magnetic resonance spectroscopy.Test results indicated that,in cement paste,a higher CEA content led to a higher porosity and a larger most probable pore diameter(MPPD).Meanwhile,SAP addition increased the porosity and MPPD of CEA cement paste at early age but decreased them after 7 d,and a higher SAP content always brought a higher porosity and MPPD.Furthermore,the addition of SAP led to a lower porosity and MPPD of CEA cement paste than that of plain cement paste after 14 d.Moreover,the porosity and MPPD of CEA cement paste decreased first and subsequently increased as the curing temperature raised.

The Effect of Tree Species on the Chemical Properties of Soil in the Rehabilitation of a Limestone Quarry at Athi River, Kenya

A comparison of field performance of Acacia xanthophloea, Schinus molle, Casuarina equisetifolia and Gravellia robusta plant species was made in an exhausted limestone quarry, backfilled with limestone mine waste in a semi-arid area in Athi River, Kenya. The aim of the study was to determine if the tree species had an influence on the soil chemical properties. The soil had alkaline pH ranging from 8.0 to 8.98, low nitrogen content （〈 0.03%）, moderate phosphorus concentrations ranging from 44.15 ppm to 21.33 ppm and high to moderate exchangeable cations （Na, Ca, Mg and K）. All the tree species exerted a positive influence on soil properties necessary for plant growth. The pH values and total phosphorus were relatively lower in soils close to the trees （0.5 m） and increased with distance from the trees, while the soil values for total nitrogen and exchangeable cations were relatively higher close to the trees. C. equisetifolia had the best growth performance and a higher positive influence on the soil chemical properties necessary for plant growth followed by A. xanthophloea. It was concluded that trees should remain a feature of quarry rehabilitation because of their role in maintaining the biophysical environment.

A Molecular Dynamic Modelling of Cross-Linked Epoxy Resin Using Reactive Force Field： Thermo-Mechanical Properties

The reactive force field was used to study the molecular dynamics of cross-linked EPON 862 （diglycidyl ether of bisphenol-F） and DETDA （diethylene toluene diamine） system in order to predict its thermo-mechanical behavior under different loading conditions. The approach for building the EPON 862/DETDA structures, cross-linking, and equilibration of the systems, and the evaluation of the models are presented. The mechanical properties such as Young＇s and shear moduli, Poisson ratio, and yields strength as well as thermal properties such as glass transition temperature and coefficient of thermal expansion are predicted. The results are in close agreement with both experimental data and simulated results in literature.

Using Binomial Tree Pricing Model in a Fuzzy Market

A model of using binomial tree pricing formulae in a fuzzy market is proposed. In the fuzzy market, a price interval can be got according to the belief degree. The rule for the reasonability of the price interval is proposed. The explicit expression of the interval is discussed in some special settings.

Challenges and Opportunities of On-farm Tree Planting as an Alternative Wood Source on Mt. Marsabit, Northern Kenya： Towards Mitigating Climate Change

Constraints and probable pathway towards increasing tree density and diversity within farmlands as a means of reducing human dependency on Mt. Marsabit forest for wood are addressed. The forest provides a carbon sink to counteract the risks and hazards associated with climate change. A structured questionnaire was administered to a sample of 205 respondents that were selected from a population of 3075 farming households using a systematic random sampling procedure. While majority of the farms （53%） had low tree density （1-10 trees）, only 8% of the farms had high density （≥ 20 trees）. About 50% and 15% farms had Grevelia robusta and Eucalyptus cammudelensis, which were grown for timber production, respectively. Broad leafed trees, like Croton megalocarpus and Moringa stenoptella had been established in 17% of the farmlands, respectively. With only 20% of the households having a fence around the crop fields, coupled by widely inter-household sharing of crop residues for grazing, tree browsing by livestock was a constraint to tree establishment. The challenges present an opportunity to establish governance structures and processes for communal responsibility and management of tree resources in the farms. A plausible approach entails the Adaptive Collaborative Management （ACM） as a process that facilitates to experiential learning and negotiation for probable actions and policies in management of natural resources.

Stochastic Air Traffic Flow Management for Demand and Capacity Balancing Under Capacity Uncertainty

This paper introduces an innovative approach to the synchronized demand-capacity balance with special focus on sector capacity uncertainty within a centrally controlled collaborative air traffic flow management(ATFM)framework.Further with previous study,the uncertainty in capacity is considered as a non-negligible issue regarding multiple reasons,like the impact of weather,the strike of air traffic controllers(ATCOs),the military use of airspace and the spatiotemporal distribution of nonscheduled flights,etc.These recessive factors affect the outcome of traffic flow optimization.In this research,the focus is placed on the impact of sector capacity uncertainty on demand and capacity balancing(DCB)optimization and ATFM,and multiple options,such as delay assignment and rerouting,are intended for regulating the traffic flow.A scenario optimization method for sector capacity in the presence of uncertainties is used to find the approximately optimal solution.The results show that the proposed approach can achieve better demand and capacity balancing and determine perfect integer solutions to ATFM problems,solving large-scale instances(24 h on seven capacity scenarios,with 6255 flights and 8949 trajectories)in 5-15 min.To the best of our knowledge,our experiment is the first to tackle large-scale instances of stochastic ATFM problems within the collaborative ATFM framework.