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1.
基于DEM的数字地形分析 总被引：29，自引：0，他引：29
该文在对数字高程模型（DEM）数据来源及结构、数字地形分析及其应用、基于DEM的地形分析中的不确定性和误差分析的基础上,以日本东北地区岩手县早池峰山为研究对象,美国MicroImage公司开发的TNTmips地理信息系统为工具,日本国土地理院发行的“数字地图25000”为基础数据,研究基于DEM的数字地形特征提取与分析方法,以及DEM精度对地形特征的影响. 研究结果表明:①以DEM为基础可提取多种地形特征,如坡度、坡向、坡面形态、流域边界、水流路径等,这些特征在地理信息系统的支持下均可用图形和属性数据来表示;②DEM水平精度对基于DEM提取的数字地形特征影响表现为:低精度的DEM将导致研究区平均坡度变小、坡度标准差变大;同时,DEM精度对不同坡度区域表现为不同的影响,其结果按坡度大致可划分为3种不同类型,即0°～10°、10°～35°以及大于35°; DEM精度对坡向的影响除平坡外变化较小,其中平坡面积随DEM精度的降低而增大;低精度的DEM将导致水文地形信息受损,这将严重影响流域水文模型参数的确立及水文过程模拟分析的精度. 相似文献
2.
为研究乡村景观的基本属性与消费者喜好度之间的关系,选择14个典型的乡村旅游地景观为研究对象,通过VR虚拟沉浸式体验进行感知与评价数据采集,以统计学软件SPSS 25.00的多向度(MDS)分析模块对其属性特征进行测量,结合相关与回归分析模块论证乡村旅游景观属性的多维特征与消费者喜好之间的关系,进而对不同景观对象的属性特征强度与喜好强度进行比较分析。结果表明,1)乡村旅游景观属性的属性特征在两维空间中具有良好的聚合性,不同的景观类型在属性特征上保持着基本一致性。2)消费者对乡村景观的属性认知与喜好度之间总体上具有一致性。3)回归分析的结果显示,青年群体消费乡村景观的最主要原因是“想在此玩耍的欲望度”。乡村景观的设计应该在满足视觉消费的同时强化乡村景观的文化价值。此方法在准确测量乡村旅游景观特征强度的基础上,结合消费者喜好度形成的原因,为乡村旅游景观的设计开发提供相应的理论依据。 相似文献
3.
为研究森林结构属性的公众偏好,以Science Direct与中国知网(www.cnki.net)为文献来源数据库,以"forest structure attribute""public preference"与"林内景观"为关键词,检索国内外森林结构属性研究的基本概况。就树种、树的大小、林木空间分布变化、采伐与林木覆盖范围、地被物与枯树倒木、可视性、林缘的自然性、沿森林小径行走时的林分变化等10个森林结构属性的公众偏好进行了综述。构建了基于水平空间、垂直空间和全空间为一体的林内森林结构属性旅游吸引物框架体系,并就未来公众对森林结构属性偏好的研究提出思考。图1参73 相似文献
4.
DEXi-type models have been used recently to assess specific problems in agricultural systems and to assess cropping-system scenarios. Finding the set of the “worst-best” (lowest scores for basic attributes that lead to the highest score for the root attribute) and “best-worst” (highest scores for basic attributes that lead to the lowest score for the root attribute) options are of interest for improving current cropping systems. As DEXi-type models revealed a monotonicity property, we used a genetic algorithm to find these two sets. These sets are small and show that only a few attributes need to have low scores to reach the best-worst options or high scores to reach the worst-best options. These attributes are those with a high sensitivity index. 相似文献
5.
用ELECTRE-I决策法评价若干小麦品种的抗赤霉病性,筛选出部分较好的原始材料。结果证明该方法精确性高,适用而广,在农业领域的多种评价研究中有重要应用价值。建议用主成分分析结果中的贡献率判定目标权重,为择权过程提供了一种实用方法。 相似文献
6.
[目的]建立基于属性差异度的多属性决策方法并说明其在水稻优选中的应用。[方法]提出属性间贴近度的概念,在此基础上对属性间的差异度进行研究,并对基于属性差异度的权重确定方法进行分析。[结果]得到了1种基于属性差异度的多属性决策方法,并针对水稻优选问题说明了该方法具有应用及可行性。[结论]丰富了多属性决策中属性权重确定的问题,并为科学合理地选择水稻品种问题提供了必要的理论支撑。 相似文献
7.
中国城乡差异显著,城镇和农村居民的消费行为也存在很大差异,应该对其消费行为分开进行研究。以农民消费者为对象,将化肥的二维属性(消费属性和投资属性)作为新变量引入Fishbein合理行为模型,构建了农民化肥购买意愿模型,考察化肥二维属性对他们购买意愿的影响。经过方差分析和结构方程分析发现,化肥的消费属性只能通过农民的态度影响其购买意愿;投资属性可以通过农民的态度对购买意愿产生正向影响,也可以通过从众心理对其购买意愿产生正向影响;并且投资属性对农民从众心理的影响更大,从众心理对购买意愿的影响比态度对购买意愿的影响更强。 相似文献
8.
Kosslyn SM Pascual-Leone A Felician O Camposano S Keenan JP Thompson WL Ganis G Sukel KE Alpert NM 《Science (New York, N.Y.)》1999,284(5411):167-170
Visual imagery is used in a wide range of mental activities, ranging from memory to reasoning, and also plays a role in perception proper. The contribution of early visual cortex, specifically Area 17, to visual mental imagery was examined by the use of two convergent techniques. In one, subjects closed their eyes during positron emission tomography (PET) while they visualized and compared properties (for example, relative length) of sets of stripes. The results showed that when people perform this task, Area 17 is activated. In the other, repetitive transcranial magnetic stimulation (rTMS) was applied to medial occipital cortex before presentation of the same task. Performance was impaired after rTMS compared with a sham control condition; similar results were obtained when the subjects performed the task by actually looking at the stimuli. In sum, the PET results showed that when patterns of stripes are visualized, Area 17 is activated, and the rTMS results showed that such activation underlies information processing. 相似文献
9.
N Hepler 《Science (New York, N.Y.)》1968,162(851):376-377
After human observers alternately view green stripes moving up and red stripes moving down for periods of 1/2 to 4 hours, they see a pink aftereffect when white stripes move up and a green aftereffect when white stripes move down. Longer exposures produce aftereffects which are visible 20 hours after stimulation. Thus, experience which pairs simple attributes (color and motion) of visual stimulation can result in a lasting modification of perception. 相似文献
10.
Utilizing soil electrical conductivity (EC) measurements and terrain attributes for precision management will require secondary soil information for adequate interpretation. The objective of this study was to determine whether readily available second-order soil surveys were of adequate quality to aid with interpreting soil EC and terrain data. For three locations in Kentucky, USA, first-order soil surveys were created, second-order surveys reports were obtained, elevation was measured and used to calculate terrain attributes (slope, aspect, plan curvature, profile curvature), and bulk soil electrical conductivity was measured. Three analytical methods (an ordinary least squares analysis and two random field analyses), visual map assessment, and examination of least-squares means were used to assess the relationships between soil EC measurements, terrain attributes and first- and second-order soil surveys. The OLS and random field analyses were problematic. However, the ranking of the OLS F-statistics appeared to reflect the general relationship between landscape variables and first-order soil surveys. The landscape variables related particularly well with soil properties that had been impacted by past soil erosion. Unfortunately, however, second-order soil surveys in this study were not created at suitable scales to adequately interpret EC and terrain data regarding erosion history or other attributes. While these surveys may provide some useful information, field measurements, sampling, and observations will likely be required to develop high quality interpretations of soil EC and terrain attribute data. 相似文献
11.
为科学制定加快大城市边缘区有序协调发展的途径和策略，提出了大城市边缘区地域特征属性的概念。从人口、用地、经济和社会等方面构建了地域特征属性界定的指标体系，利用模糊综合评价法构建了地域特征属性的界定模型。对北京城市边缘区内的小汤山镇、潭柘寺镇、温泉镇和万柳地区的地域特征属性进行了界定，结果表明：小汤山镇的地域特征属性值为0．4210，具有城市外边缘区的特征；潭柘寺镇的为0．0758。具有乡村腹地的特征；温泉镇为0．4922，具有城市内边缘区的特征；万柳地区为0．7116，具有城市内边缘区的特征。界定结果与实际情况相符。所提出的基于模糊综合评价的大城市边缘区地域特征属性的界定方法是可行、有效的。 相似文献
12.
Complementary hemispheric specialization in monkeys 总被引：5，自引：0，他引：5
Twenty-five split-brain monkeys were taught to discriminate two types of visual stimuli that engage lateralized cerebral processing in human subjects. Differential lateralization for the two kinds of discriminations was found; the left hemisphere was better at distinguishing between tilted lines and the right hemisphere was better at discriminating faces. These results indicate that lateralization of cognitive processing appeared in primates independently of language or handedness. In addition, cerebral lateralization in monkeys may provide an appropriate model for studying the biological basis of hemispheric specialization. 相似文献
13.
在分析城市河流景观的研究现状的基础上,提出从城市河流历史文化景观再生的观点来进行河流景观研究的理念.分析得出城市河流景观的生态属性、文化属性、社会属性、美学属性的特征及研究重点,并以此为依据进行城市河流景现的保护与利用的科研与实践工作. 相似文献
14.
典型黄茶滋味品质特征属性及相关滋味化学组分 总被引：3，自引：0，他引：3
【目的】黄茶是我国的特有茶类,特殊的“闷黄”工艺形成了黄茶独特的滋味品质,探究黄茶感官滋味特征属性及其相关的化学物质有助于进一步明确黄茶滋味特征形成的化学贡献机制,为黄茶生产标准化提供理论依据。【方法】本研究基于我国传统黄茶产区典型黄茶样品,经滋味品质感官审评、化学组分检测,结合化学计量学分析方法研究典型黄茶滋味特征属性及相关化学组分。【结果】醇度和甘甜感是黄茶滋味的典型共有属性,不同产区及不同类型黄茶产品感官滋味在鲜、厚、收敛性及粗糙感等属性方面表现出差异;不同产区黄茶在滋味化学组分含量方面也表现出较大差异。本试验的典型黄茶样品中,滋味厚度和收敛性较为相关;粗糙感主要由鲜叶原料较低的嫩度引起,是区分安徽多叶型黄茶和其他黄茶类别的重要贡献因子,同时推测由于本试验条件下的黄大茶样品没食子酸含量较高,化学组分中没食子酸、没食子酸/黄酮总量比值（GA/Fla）、没食子酸/儿茶素总量比值（GA/Ca）及没食子酸/生物碱总量比值（GA/Alk）与滋味粗糙感呈现较高相关性。黄茶滋味鲜感主要与茶汤中氨基酸有关,其中谷氨酸、茶氨酸/氨基酸总量比值（Thea/aa）及鲜味氨基酸总量/氨基酸总量比值（Umami/aa）表现出与黄茶滋味鲜感的较强相关性。【结论】醇度和甘甜感是黄茶滋味的典型共有属性,粗糙感是多叶型黄茶的典型滋味特征。本试验条件下由于样品特点而表现出没食子酸、GA/Fla、GA/Ca及GA/Alk与黄茶滋味糙感相关;谷氨酸、Thea/aa、Umami/aa与黄茶滋味鲜感高度相关。 相似文献
15.
Three-dimensional (3D) movement of neuroprosthetic devices can be controlled by the activity of cortical neurons when appropriate algorithms are used to decode intended movement in real time. Previous studies assumed that neurons maintain fixed tuning properties, and the studies used subjects who were unaware of the movements predicted by their recorded units. In this study, subjects had real-time visual feedback of their brain-controlled trajectories. Cell tuning properties changed when used for brain-controlled movements. By using control algorithms that track these changes, subjects made long sequences of 3D movements using far fewer cortical units than expected. Daily practice improved movement accuracy and the directional tuning of these units. 相似文献
16.
Effect of Rapid Cold Hardening on the Cold Tolerance of the Larvae of the Rice Stem Borer,Chilo suppressalis （Walker） 总被引：1，自引：0，他引：1
QIANG Cheng-kui ;DU Yu-zhou ;YU Ling-ya ;CUI Ya-dong ;ZHENG Fu-shan ;LU Ming-xing 《中国农业科学(英文版)》2008,7(3):321-328
The effects of rapid cold hardening （RCH） on the cold tolerance of the last instar larvae of Chilo suppressalis （Walker） were evaluated for the first time. The discriminating temperature, induction, detection, duration and extent of RCH of the larvae in the laboratory were tested, and the supercooling points （SCPs） and the contents of water and lipid of the larvae after RCH treatment were determined, respectively. The results showed that the discriminating temperature of the larvae was about -21℃. Mean survival rates of the larvae which exposed to either 0 or 5℃ for 2 and 4 h before exposure to the discriminating temperature for 2 h were significantly higher than those of the control groups （P 〈 0.05）. Moreover, the highest survival rate appeared in the larvae after 0℃ for 4 h treatment. The protection against low temperature gained by RCH at 0℃ for 4 h was rapidly lost on return to 28℃. Mean survival rates of RCH larvae were significantly higher than those of non-acclimated （NACC） larvae and acclimation （ACC） larvae when they were exposed to the discriminating temperature for 2 or 4 h （P〈 0.05）. Moreover, the rates of NACC, ACC, RCH and ACC ＋ RCH larvae from 2 to 6 h to the discriminating temperature resulted in a significant decline. The values of SCPs and the contents of lipid of the larvae which exposed to either 0 or 5℃ for 2 and 4 h showed no significant difference at 0.05 level compared to those of the control groups. But the contents of water in the larvae were obviously decreased. Therefore, it could be concluded that RCH could enhance cold tolerance and affect partly physiological and biochemical components of the larvae of C. suppressalis, but the underlying mechanisms needs to be further explored. 相似文献
17.
Watanabe M Cheng K Murayama Y Ueno K Asamizuya T Tanaka K Logothetis N 《Science (New York, N.Y.)》2011,334(6057):829-831
Although recent psychophysical studies indicate that visual awareness and top-down attention are two distinct processes, it is not clear how they are neurally dissociated in the visual system. Using a two-by-two factorial functional magnetic resonance imaging design with binocular suppression, we found that the visibility or invisibility of a visual target led to only nonsignificant blood oxygenation level-dependent (BOLD) effects in the human primary visual cortex (V1). Directing attention toward and away from the target had much larger and robust effects across all study participants. The difference in the lower-level limit of BOLD activation between attention and awareness illustrates dissociated neural correlates of the two processes. Our results agree with previously reported V1 BOLD effects on attention, while they invite a reconsideration of the functional role of V1 in visual awareness. 相似文献
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公路网评价对于了解区域公路网状态和交通需求间的关系非常重要．讨论了公路网属性表示为区间数的问题，通过计算属性值相对于属性等级的距离矩阵得到相应的加权可变相似度，再对可变相似度进行归一化处理，作为各属性等级的权重向量，同时应用级别特征公式求得综合属性值进行综合评价.实例表明，该方法和其他方法的评价结果一致，且能给出不同标准下的评价结果，计算过程简明且有效，而且能向属性值为其他类型的不确定量进行拓广. 相似文献
20.
People often are unable to report the content of ignored information, but it is unknown whether this reflects a complete failure to perceive it (inattentional blindness) or merely that it is rapidly forgotten (inattentional amnesia). Here functional imaging is used to address this issue by measuring brain activity for unattended words. When attention is fully engaged with other material, the brain no longer differentiates between meaningful words and random letters, even when they are looked at directly. These results demonstrate true inattentional blindness for words and show that visual recognition wholly depends on attention even for highly familiar and meaningful stimuli at the center of gaze. 相似文献