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111.
Developing augmented reality (AR) applications for mobile devices and outdoor environments has historically required a number of technical trade-offs related to tracking. One approach is to rely on computer vision which provides very accurate tracking, but can be brittle, and limits the generality of the application. Another approach is to rely on sensor-based tracking which enables widespread use, but at the cost of generally poor tracking performance. In this paper we present and evaluate a new approach, which we call Indirect AR, that enables perfect alignment of virtual content in a much greater number of application scenarios.To achieve this improved performance we replace the live camera view used in video see through AR with a previously captured panoramic image. By doing this we improve the perceived quality of the tracking while still maintaining a similar overall experience. There are some limitations of this technique, however, related to the use of panoramas. We evaluate these boundaries conditions on both a performance and experiential basis through two user studies. The result of these studies indicates that users preferred Indirect AR over traditional AR in most conditions, and when conditions do degrade to the point the experience changes, Indirect AR can still be a very useful tool in many outdoor application scenarios. 相似文献
112.
Almost all subspace clustering algorithms proposed so far are designed for numeric datasets. In this paper, we present a k-means type clustering algorithm that finds clusters in data subspaces in mixed numeric and categorical datasets. In this method, we compute attributes contribution to different clusters. We propose a new cost function for a k-means type algorithm. One of the advantages of this algorithm is its complexity which is linear with respect to the number of the data points. This algorithm is also useful in describing the cluster formation in terms of attributes contribution to different clusters. The algorithm is tested on various synthetic and real datasets to show its effectiveness. The clustering results are explained by using attributes weights in the clusters. The clustering results are also compared with published results. 相似文献
113.
本文根据(1)所提出的FNN结构,首先讨论它的学习方法,字除了可以应用到FNN上的输入均值和输出权重的调整外,还可以用于实现网络连线的裁剪。然后对混合学习竞争学习与反向传播学习结合使用)算法的实现问题加以探讨。 相似文献
114.
A ranking selection-based particle swarm optimizer for engineering design optimization problems 总被引:2,自引:2,他引:0
Particle swarm optimization (PSO) algorithms have been proposed to solve optimization problems in engineering design, which
are usually constrained (possibly highly constrained) and may require the use of mixed variables such as continuous, integer,
and discrete variables. In this paper, a new algorithm called the ranking selection-based PSO (RSPSO) is developed. In RSPSO,
the objective function and constraints are handled separately. For discrete variables, they are partitioned into ordinary
discrete and categorical ones, and the latter is managed and searched directly without the concept of velocity in the standard
PSO. In addition, a new ranking selection scheme is incorporated into PSO to elaborately control the search behavior of a
swarm in different search phases and on categorical variables. RSPSO is relatively simple and easy to implement. Experiments
on five engineering problems and a benchmark function with equality constraints were conducted. The results indicate that
RSPSO is an effective and widely applicable optimizer for optimization problems in engineering design in comparison with the
state-of-the-art algorithms in the area. 相似文献
115.
116.
林业调查中采用的基本方法是全林调查法和局部估测法,而局部估测方法中最常用的是角规测量法与标准地法,在林地调查中角规法误差较大,而标准地法又存在着难于布设的问题。本研究提出的面积单元线性测量法,可方便快捷地进行局部估测,节省人力和时间,同时又达到了较高的精度,特别适用于不规则林分的调查。 相似文献
117.
The antioxidant -tocopherol (vitamin E), applied in a basal trunk band to the green ash tree,Fraxinus pennsylvanica var.subintergerrinia, elicited an alteration of foliar feeding byMalacosoma disstria larvae (Lepidoptera: Lasiocampidae). The bioassayed effects were dependent on the dosage of elicitor, the time after elicitation, and the position in the tree. Leaves for chemical analysis were collected from trees receiving two dosages and at two intervals after elicitation. Compounds in the ethyl acetate extractables from the ash tree leaves were separated by TLC and HPLC. TLC separations showed differences in the nonhydrolyzed extractables attributable to elicitor dosage and time after elicitation. TLC-resolved differences were also evident among acid-hydrolyzed samples. HPLC-resolved profiles revealed eight peaks in the nonhydrolyzed extractables that were quantitatively negatively correlated with larval feeding preference between elicited versus control foliage on at least one of the two sampling dates. Results from this study and other investigations reported in the literature indicate that the antioxidant-tocopherol (vitamin E) can function as an environmental-stress elicitor of alterable defensive chemistry in green ash and other plants. 相似文献
118.
以榆林飞播林区的土壤微生物、土壤养分和土壤可溶性盐为研究对象,对林区土壤可溶性盐的变化规律及其与土壤养分、微生物的相关性进行研究,为水土资源可持续利用以及飞播造林功效的提高提供理论依据。研究表明,研究区土壤属硫酸盐型,土壤层分异特征不显著,土壤仍处于初级发育阶段。土壤总盐与养分的相关性不明显,适当增加K+利于真菌的存活和生物量的积累,在1 kg土壤中,每增加1gK+,真菌数量就会增加14个左右。在土层表层,适量减少Cl-能促进土壤细菌的生长,在40 cm 土层的盐分上行过程中出现表聚现象,在土壤中层,出现板结现象,在土壤底层,HCO3-和Na+质量分数的增加,有利于土壤全氮质量分数的增加,且 HCO3-的影响力最强。 相似文献
119.
Crane is widely used to move a heavy object from one place to another not only in manufacturing industry but also service industry. As an important resource in the train oilcan repairing, crane scheduling affects directly the productivity of the systems. In this paper, we study cyclic single crane scheduling problem with two parallel train oilcan repairing lines, where jobs are loaded into the line at one end and unloaded at the other end. The processing time at each workstation must be within a given range. There is no buffer between these stations. A crane is used to move jobs between the workstations in two parallel lines. The objective is to schedule the moves to minimize the production cycle. We proposed a time way diagram for two parallel lines and developed a mixed integer linear programming model. Then we extended the model to the scheduling problem with multi-station to eliminate the bottleneck in lines. Examples are given to demonstrate the effectiveness of the model. 相似文献
120.
A mixed integer linear model for selecting the best decision making unit (DMU) in data envelopment analysis (DEA) has recently been proposed by Foroughi [Foroughi, A. A. (2011a). A new mixed integer linear model for selecting the best decision making units in data envelopment analysis. Computers and Industrial Engineering, 60(4), 550–554], which involves many unnecessary constraints and requires specifying an assurance region (AR) for input weights and output weights, respectively. Its selection of the best DMU is easy to be affected by outliers and may sometimes be incorrect. To avoid these drawbacks, this paper proposes three alternative mixed integer linear programming (MILP) models for identifying the most efficient DMU under different returns to scales, which contain only essential constraints and decision variables and are much simpler and more succinct than Foroughi’s. The proposed alternative MILP models can make full use of input and output information without the need of specifying any assurance regions for input and output weights to avoid zero weights, can make correct selections without being affected by outliers, and are of significant importance to the decision makers whose concerns are not DMU ranking, but the correct selection of the most efficient DMU. The potential applications of the proposed alternative MILP models and their effectiveness are illustrated with four numerical examples. 相似文献