Understanding metal accumulation at organ level in roots, leaves and seeds in O. glaberrima (OG) is crucial for improving physiological and metabolic aspects in growing Asian and African rice in salted areas. The micr...Understanding metal accumulation at organ level in roots, leaves and seeds in O. glaberrima (OG) is crucial for improving physiological and metabolic aspects in growing Asian and African rice in salted areas. The micro-analytical imaging techniques are required to reveal its accumulation and distribution within plant tissues. PIXE studies have been performed to determine different elements in rice plants. The existing microbeam analytical technique at the iThemba LABS will be applied for the 2D image mapping of fresh rice tissues to perform a concentration of low atomic mass elements (such as Al, Si, P, S, Cl, Ca, Ti, Mn, Fe, Cu, Br, Zn and K) with detection limits of typically 1-10 μg/g. Comparison of the distribution of the elements between leaves, root and seed samples using uptake and distribution of elements in particular environmental conditions with potential amount of salt in water have been performed. We are also expecting to indicate metal exclusion as salt tolerance strategies from leaves, root, and seed compartments using matrix correlation between samples and between elements on rice species.展开更多
The indoor robots are expected to complete metric navigation tasks safely and efficiently in complex environments, which is the essential prerequisite for accomplishing other high-level operation tasks. 2 D occupancy ...The indoor robots are expected to complete metric navigation tasks safely and efficiently in complex environments, which is the essential prerequisite for accomplishing other high-level operation tasks. 2 D occupancy grid maps are sufficient to support the robots in avoiding all obstacles in the environments during navigation. However, the maps based on normal laser scans only reflect a horizontal slice of the environment, which may cause the problem of some obstacles missing or misinterpreting their exact boundaries,thereby threatening the safety and efficiency of robot navigation. This paper presents a 2 D mapping method based on virtual laser scans to provide a more comprehensive representation of obstacles for indoor robot navigation. The resulting maps can accurately represent the top-down projected contours of all obstacles no matter where their vertical positions are. The virtual laser scans are initially generated from raw data of an RGB-D camera based on the filtering, projection, and polar-coordinate scanning. The scans are fed directly to the laser-based simultaneous localization and mapping(SLAM) algorithms to update the current map and robot position. Two auxiliary strategies are proposed to further improve the quality of maps by reducing the impact of the narrow field of view and the blind zone of the RGB-D camera on the observations. In this paper, the improved virtual laser generation method makes the extracted 2 D observations fit the laser-based SLAM algorithms, and two auxiliary strategies are novel ways to improve map quality. The generated maps can reflect the comprehensive obstacle information in indoor environments with good accuracy. The comparative experiments are carried out based on four simulation scenarios and three real-world scenarios to prove the effectiveness of our 2 D mapping method.展开更多
A self-adaptive parallel encryption algorithm based on discrete 2D-Logistic map is developed according to the position scrambling and diffusion of multi-direction in variable space of spatial chaos. The binary sequenc...A self-adaptive parallel encryption algorithm based on discrete 2D-Logistic map is developed according to the position scrambling and diffusion of multi-direction in variable space of spatial chaos. The binary sequences b1b2b3···bn are obtained according to the user key, in which the binary sequence 0 and 1 denote distribution mode of processors and the number of binary sequence n denotes cycle number. Then the pseudorandom 2D matrix is generated by 2D-Logistic map, and adaptive segmentation is applied in image matrix and pseudorandom matrix according to the value and the number of binary sequence. The parallel operation is used among blocks to improve efficiency and meet real-time demand in transmission processes. However, the pixel permutation is applied in partitioned matrix through ergodic matrix generated by pseudo-random matrix-block to decrease the correlation of adjacent pixels. Then the pixel substitution is used for fully diffusing through cipher block chaining mode until n cycles. The proposed algorithm can meet the three requirements of parallel operation in image encryption and the real-time requirement in transmission processes. The security is proved by theoretical analysis and simulation results.展开更多
医学三维图像(如CT、MRI等)和二维图像(如X光)的配准技术已经被广泛应用于临床诊断和手术规划中.医学图像配准的实质为使用优化算法寻找某种空间变换,使两张图像在空间以及结构上对齐.配准过程中往往由于优化算法寻优精度不高、易陷入...医学三维图像(如CT、MRI等)和二维图像(如X光)的配准技术已经被广泛应用于临床诊断和手术规划中.医学图像配准的实质为使用优化算法寻找某种空间变换,使两张图像在空间以及结构上对齐.配准过程中往往由于优化算法寻优精度不高、易陷入局部极值的问题导致配准质量低.针对此问题,提出一种改进的平衡优化器算法(improved equilibrium optimizer based on Logistic-Tent chaos map and Levy flight,LTEO),首先针对种群初始化容易分布不均匀,且随机性太高的问题,引入Logistic-Tent混沌映射对种群进行初始化,提高种群多样性,使它们尽可能地分布于搜索空间内;对迭代函数进行更新,使得优化算法更注重全局范围的搜索,提高算法收敛速度并利于找到全局最优解;引入Levy飞行策略对停滞粒子进行扰动,防止算法陷入局部极值.最后将改进的平衡优化器算法用于2D/3D医学图像配准任务,并对配准过程中数据的频繁传输进行优化,降低配准耗时.通过基准函数测试和临床配准实验对算法进行验证,改进后的平衡优化器可有效提高寻优精度和稳定性,并提高医学图像配准的质量.展开更多
针对HIT-TENA体系结构在试验过程中对试验场景的显示需求,以Visual Studio 2008为开发平台,利用面向对象编程语言C++,基于Map X控件,开发二维场景显示软件。阐述了HIT-TENA体系结构的组成及二维场景显示软件在HIT-TENA中的地位与作用,...针对HIT-TENA体系结构在试验过程中对试验场景的显示需求,以Visual Studio 2008为开发平台,利用面向对象编程语言C++,基于Map X控件,开发二维场景显示软件。阐述了HIT-TENA体系结构的组成及二维场景显示软件在HIT-TENA中的地位与作用,根据二维场景显示软件的功能要求,使用UML语言对该软件进行了需求分析、概要设计及详细设计,详细介绍了该软件与HIT-TENA中间件的数据交互接口实现以及设备信息的实时绘制的实现,并利用一个虚拟试验系统对软件进行测试,软件运行良好。展开更多
文摘Understanding metal accumulation at organ level in roots, leaves and seeds in O. glaberrima (OG) is crucial for improving physiological and metabolic aspects in growing Asian and African rice in salted areas. The micro-analytical imaging techniques are required to reveal its accumulation and distribution within plant tissues. PIXE studies have been performed to determine different elements in rice plants. The existing microbeam analytical technique at the iThemba LABS will be applied for the 2D image mapping of fresh rice tissues to perform a concentration of low atomic mass elements (such as Al, Si, P, S, Cl, Ca, Ti, Mn, Fe, Cu, Br, Zn and K) with detection limits of typically 1-10 μg/g. Comparison of the distribution of the elements between leaves, root and seed samples using uptake and distribution of elements in particular environmental conditions with potential amount of salt in water have been performed. We are also expecting to indicate metal exclusion as salt tolerance strategies from leaves, root, and seed compartments using matrix correlation between samples and between elements on rice species.
基金supported by National Natural Science Foundation of China(Nos.U1813215 and 61773239)the Taishan Scholars Program of Shandong Province(No.ts201511005)。
文摘The indoor robots are expected to complete metric navigation tasks safely and efficiently in complex environments, which is the essential prerequisite for accomplishing other high-level operation tasks. 2 D occupancy grid maps are sufficient to support the robots in avoiding all obstacles in the environments during navigation. However, the maps based on normal laser scans only reflect a horizontal slice of the environment, which may cause the problem of some obstacles missing or misinterpreting their exact boundaries,thereby threatening the safety and efficiency of robot navigation. This paper presents a 2 D mapping method based on virtual laser scans to provide a more comprehensive representation of obstacles for indoor robot navigation. The resulting maps can accurately represent the top-down projected contours of all obstacles no matter where their vertical positions are. The virtual laser scans are initially generated from raw data of an RGB-D camera based on the filtering, projection, and polar-coordinate scanning. The scans are fed directly to the laser-based simultaneous localization and mapping(SLAM) algorithms to update the current map and robot position. Two auxiliary strategies are proposed to further improve the quality of maps by reducing the impact of the narrow field of view and the blind zone of the RGB-D camera on the observations. In this paper, the improved virtual laser generation method makes the extracted 2 D observations fit the laser-based SLAM algorithms, and two auxiliary strategies are novel ways to improve map quality. The generated maps can reflect the comprehensive obstacle information in indoor environments with good accuracy. The comparative experiments are carried out based on four simulation scenarios and three real-world scenarios to prove the effectiveness of our 2 D mapping method.
文摘A self-adaptive parallel encryption algorithm based on discrete 2D-Logistic map is developed according to the position scrambling and diffusion of multi-direction in variable space of spatial chaos. The binary sequences b1b2b3···bn are obtained according to the user key, in which the binary sequence 0 and 1 denote distribution mode of processors and the number of binary sequence n denotes cycle number. Then the pseudorandom 2D matrix is generated by 2D-Logistic map, and adaptive segmentation is applied in image matrix and pseudorandom matrix according to the value and the number of binary sequence. The parallel operation is used among blocks to improve efficiency and meet real-time demand in transmission processes. However, the pixel permutation is applied in partitioned matrix through ergodic matrix generated by pseudo-random matrix-block to decrease the correlation of adjacent pixels. Then the pixel substitution is used for fully diffusing through cipher block chaining mode until n cycles. The proposed algorithm can meet the three requirements of parallel operation in image encryption and the real-time requirement in transmission processes. The security is proved by theoretical analysis and simulation results.
文摘医学三维图像(如CT、MRI等)和二维图像(如X光)的配准技术已经被广泛应用于临床诊断和手术规划中.医学图像配准的实质为使用优化算法寻找某种空间变换,使两张图像在空间以及结构上对齐.配准过程中往往由于优化算法寻优精度不高、易陷入局部极值的问题导致配准质量低.针对此问题,提出一种改进的平衡优化器算法(improved equilibrium optimizer based on Logistic-Tent chaos map and Levy flight,LTEO),首先针对种群初始化容易分布不均匀,且随机性太高的问题,引入Logistic-Tent混沌映射对种群进行初始化,提高种群多样性,使它们尽可能地分布于搜索空间内;对迭代函数进行更新,使得优化算法更注重全局范围的搜索,提高算法收敛速度并利于找到全局最优解;引入Levy飞行策略对停滞粒子进行扰动,防止算法陷入局部极值.最后将改进的平衡优化器算法用于2D/3D医学图像配准任务,并对配准过程中数据的频繁传输进行优化,降低配准耗时.通过基准函数测试和临床配准实验对算法进行验证,改进后的平衡优化器可有效提高寻优精度和稳定性,并提高医学图像配准的质量.
文摘针对HIT-TENA体系结构在试验过程中对试验场景的显示需求,以Visual Studio 2008为开发平台,利用面向对象编程语言C++,基于Map X控件,开发二维场景显示软件。阐述了HIT-TENA体系结构的组成及二维场景显示软件在HIT-TENA中的地位与作用,根据二维场景显示软件的功能要求,使用UML语言对该软件进行了需求分析、概要设计及详细设计,详细介绍了该软件与HIT-TENA中间件的数据交互接口实现以及设备信息的实时绘制的实现,并利用一个虚拟试验系统对软件进行测试,软件运行良好。
