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1.
One of the most challenging issues in radio received signal strength (RSS)-based localization systems is the generation and distribution of a radio map with a coordinate system linked with spatial information in a large indoor space. This study proposes a novel spatial-tagged radio-mapping system (SRS) that effectively combines the heterogeneous properties of LiDAR and mobile phones to simultaneously perform both spatial and radio mappings. The SRS consists of synchronization, localization, and map building processes, and enables real-time spatial and radio mapping. In the synchronization process, the distance range, motion data, and radio signals obtained through the LiDAR and mobile phone are collected in nodal units according to the sensing time. In the localization process, a feature variance filter is used to control the number of features generated from LiDAR and estimate the positions at which the nodes are generated in real time according to the motion data and radio signals. In map building, the estimated positions of the nodes are used to extract spatial and radio maps by using a unified location coordinate system. To ensure mobility, the SRS is manufactured in the form of a backpack supporting LiDAR and a mobile phone; the usefulness of the system is experimentally verified. The experiments are performed in a large indoor shopping mall with a complex structure. The experimental results demonstrated that a common coordinate system could be used to build spatial and radio maps with high accuracy and efficiency in real time. In addition, the field applicability of the SRS to location-based services is experimentally verified by applying the constructed radio map to well-known fingerprinting algorithms using the heterogeneous mobile phones.  相似文献   
2.
The ‐centroid problem or leader–follower problem is generalized considering different customer choice rules where a customer may use facilities belonging to different firms, if the difference in travel distance (or time) is small enough. Assuming essential goods, some particular customer choice rules are analyzed. Linear programming formulations for the generalized ‐medianoid and ‐centroid problems are presented and an exact solution approach is applied. Some computational examples are included.  相似文献   
3.
Graphene has been predicted to develop a magnetic moment by proximity effect when placed on a ferromagnetic film, a promise that could open exciting possibilities in the fields of spintronics and magnetic data recording. In this work, the interplay between the magnetoresistance of graphene and the magnetization of an underlying ferromagnetic insulating film is studied in detail. A clear correlation between both magnitudes is observed but through a careful modeling of the magnetization and the weak localization measurements, that such correspondence can be explained by the effects of the magnetic stray fields arising from the ferromagnetic insulator is found. The results emphasize the complexity arising at the interface between magnetic and 2D materials.  相似文献   
4.
The perceived locations of paired auditory images, simulating direct sounds and their echoes, have been recently studied in budgerigars (Melopsittacus undulatus; M. L. Dent & R. J. Dooling, 2003a, 2003b). In this article, the authors extend those experiments to include measurements of the precedence effect using a discrimination paradigm in two additional bird species: canaries (Serinus canaria) and zebra finches (Taeniopygia guttata). Although time courses of summing localization, localization dominance, and echo thresholds were similar across all species, budgerigars had slightly higher overall levels of discrimination. The results from these experiments add further support that the precedence effect in birds is similar to that found in other animals and that the ability to suppress echoes that might degrade localization and auditory object perception may be a general property of the vertebrate auditory system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
本文针对背景噪声为冲击噪声的情况,提出了一种新的近场源二维参数估计方法.本方法利用协变异(或协变异系数)构造矩阵,并通过求根的方法估计近场源的方向角和距离参数.该算法可以抑制冲击噪声对估计性能的影响,同时具有无需谱峰搜索的优点.仿真实验证明了该算法的有效性.  相似文献   
6.
This paper introduces results on placement and communications minimization for systems of affine recurrence equations. We show how to classify the dependences according to the number and nature of communications they may result in. We give both communication-free conditions and conditions for an efficient use of broadcast or neighbor-to-neighbor communication primitives. Since the dependences of a problem can generally not be all communication-free, we finally introduce a heuristic to globally minimize the communications based on the classification of dependences.  相似文献   
7.
We present a robot-assisted wayfinding system for the visually impaired in structured indoor environments. The system consists of a mobile robotic guide and small passive RFID sensors embedded in the environment. The system is intended for use in indoor environments, such as office buildings, supermarkets and airports. We describe how the system was deployed in two indoor environments and evaluated by visually impaired participants in a series of pilot experiments. We analyze the system’s successes and failures and outline our plans for future research and development.  相似文献   
8.
A detection-theoretic analysis of the auditory localization of dual-impulse stimuli is described, and a model for the processing of spatial cues in the echo pulse is developed. Although for over 50 years "echo suppression" has been the topic of intense theoretical and empirical study within the hearing sciences, only a rudimentary understanding of its mechanisms has emerged. In this article, psychometric functions and results from matching studies are used in developing a model that specifies the perceived position of the echo pulse as a normal deviate, with an expectation that is a logistic function of the echo delay and a variance that depends on interaural time difference. Loss of information in the echo event is quantified as a decline in the efficiency with which the binaural system receives information from the lag impulse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
应用焦锑酸盐沉淀技术对水稻花后衰退珠心和胚乳发育初期进行了Ca^2 的超微细胞化学定位。结果显示在初始衰退的珠心细胞中Ca^2 主要分布于液泡膜上和核内;在衰退中期的珠心细胞中,Ca^ 主要分布在核膜、液泡膜及质膜上;在严重衰退的珠心细胞,Ca^2 仅存在于液泡中。珠心降解的Ca^2 跨过胚囊壁,通过质外体向胚乳内运输;发育初期的胚乳细胞,Ca^2 主要位于胞间隙,线粒体和液泡中也有少量分布。讨论了Ca^2 与珠心PCD的关系。  相似文献   
10.
机载雷达成像中的两种改进多普勒质心估计算法   总被引:1,自引:0,他引:1  
多普勒质心估计是机载脉冲多普勒雷达DBS成像技术中最为关键的步骤之一.本文针对载机惯导参数误差较大的实际情况,提出了改进的频域和时域多普勒质心估计算法.新的算法克服了传统算法受地面场景非均匀性和回波信号起伏的影响,大大提高了估计的精度.最后将这些算法用于某型脉冲多普勒雷达的实测数据,成像结果证明了算法的有效性.  相似文献   
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