Improved look-up table method of computer-generated holograms

2016 ◽  
Vol 55 (32) ◽  
pp. 9255 ◽  
Author(s):  
Hui Wei ◽  
Guanghong Gong ◽  
Ni Li
2014 ◽  
Vol 23 (4) ◽  
pp. 043013
Author(s):  
Yingqing Huang ◽  
Kai Zhao ◽  
Xingpeng Yan ◽  
Chuang Pei ◽  
Xiaoyu Jiang

2021 ◽  
Vol 10 (2) ◽  
pp. 79
Author(s):  
Ching-Yun Mu ◽  
Tien-Yin Chou ◽  
Thanh Van Hoang ◽  
Pin Kung ◽  
Yao-Min Fang ◽  
...  

Spatial information technology has been widely used for vehicles in general and for fleet management. Many studies have focused on improving vehicle positioning accuracy, although few studies have focused on efficiency improvements for managing large truck fleets in the context of the current complex network of roads. Therefore, this paper proposes a multilayer-based map matching algorithm with different spatial data structures to deal rapidly with large amounts of coordinate data. Using the dimension reduction technique, the geodesic coordinates can be transformed into plane coordinates. This study provides multiple layer grouping combinations to deal with complex road networks. We integrated these techniques and employed a puncture method to process the geometric computation with spatial data-mining approaches. We constructed a spatial division index and combined this with the puncture method, which improves the efficiency of the system and can enhance data retrieval efficiency for large truck fleet dispatching. This paper also used a multilayer-based map matching algorithm with raster data structures. Comparing the results revealed that the look-up table method offers the best outcome. The proposed multilayer-based map matching algorithm using the look-up table method is suited to obtaining competitive performance in identifying efficiency improvements for large truck fleet dispatching.


2015 ◽  
Vol 35 (2) ◽  
pp. 0209001
Author(s):  
蒋晓瑜 Jiang Xiaoyu ◽  
丛彬 Cong Bin ◽  
裴闯 Pei Chuang ◽  
闫兴鹏 Yan Xingpeng ◽  
赵锴 Zhao Kai

2015 ◽  
Vol 8 (4) ◽  
pp. 1901-1911 ◽  
Author(s):  
D. van Dinther ◽  
C. R. Wood ◽  
O. K. Hartogensis ◽  
A. Nordbo ◽  
E. J. O'Connor

Abstract. In this study, the crosswind (wind component perpendicular to a path, U⊥) is measured by a scintillometer and estimated with Doppler lidar above the urban environment of Helsinki, Finland, for 15 days. The scintillometer allows acquisition of a path-averaged value of U⊥ (U⊥), while the lidar allows acquisition of path-resolved U⊥ (U⊥ (x), where x is the position along the path). The goal of this study is to evaluate the performance of scintillometer U⊥ estimates for conditions under which U⊥ (x) is variable. Two methods are applied to estimate U⊥ from the scintillometer signal: the cumulative-spectrum method (relies on scintillation spectra) and the look-up-table method (relies on time-lagged correlation functions). The values of U⊥ of both methods compare well with the lidar estimates, with root-mean-square deviations of 0.71 and 0.73 m s−1. This indicates that, given the data treatment applied in this study, both measurement technologies are able to obtain estimates of U⊥ in the complex urban environment. The detailed investigation of four cases indicates that the cumulative-spectrum method is less susceptible to a variable U⊥ (x) than the look-up-table method. However, the look-up-table method can be adjusted to improve its capabilities for estimating U⊥ under conditions under for which U⊥ (x) is variable.


Sign in / Sign up

Export Citation Format

Share Document