Dempster-Shafer evidence theory, also called the theory of belief function, is widely used for uncertainty modeling and reasoning. However, when the size and number of focal elements are large, the evidence combinatio...Dempster-Shafer evidence theory, also called the theory of belief function, is widely used for uncertainty modeling and reasoning. However, when the size and number of focal elements are large, the evidence combination will bring a high computational complexity. To address this issue,various methods have been proposed including the implementation of more efficient combination rules and the simplifications or approximations of Basic Belief Assignments(BBAs). In this paper,a novel principle for approximating a BBA into a simpler one is proposed, which is based on the degree of non-redundancy for focal elements. More non-redundant focal elements are kept in the approximation while more redundant focal elements in the original BBA are removed first. Three types of degree of non-redundancy are defined based on three different definitions of focal element distance, respectively. Two different implementations of this principle for BBA approximations are proposed including a batch and an iterative type. Examples, experiments, comparisons and related analyses are provided to validate proposed approximation approaches.展开更多
AIM: To investigate whether the response of a central hexagonal element corresponding to the macular area in conventional multifocal electroretinography(mfERG) tests was the same as that of experimental mfERG using si...AIM: To investigate whether the response of a central hexagonal element corresponding to the macular area in conventional multifocal electroretinography(mfERG) tests was the same as that of experimental mfERG using single central hexagonal element stimulation. METHODS: Prospective, observational study. Thirty healthy subjects were included in this study. mfERG recordings were performed according to two protocols: stimulus with 37 hexagonal elements(protocol 1), and stimulus with a single central element created by deactivating the other 36 hexagonal elements(protocol 2). We compared differences between ring 1 parameters in each protocol. RESULTS: In protocol 1, the first positive component(P1) implicit time and P1 amplitude were 37.8±1.8 ms and 6.3±2.7 μV. After single element stimulation(protocol 2), double positive waves appeared. The implicit time and amplitude of P1 were 40.7±2.4 ms(P<0.001) and 9.1±3.3 μV(P=0.001), respectively. The implicit time and amplitude of the second positive component(P2) were 68.0±4.5 ms(P<0.001, compared with P1 in protocol 1) and 12.3±4.7 μV(P<0.001, compared with P1 in protocol 1), respectively. The amplitude of P2 in protocol 2 was about two times higher than that of P1 in protocol 1. CONCLUSION: mfERG responses of a central hexagonal element in a single element stimulation protocol are different from those of multiple element stimulation. The positive wave is more enhanced compared to that of the conventional protocol and it elongated into two wavelets.展开更多
基金the National Natural Science Foundation of China (Nos. 61671370, 61573275)Postdoctoral Science Foundation of China (No. 2016M592790)+1 种基金Postdoctoral Science Research Foundation of Shaanxi Province, China (No. 2016BSHEDZZ46)Fundamental Research Funds for the Central Universities, China (No. xjj201066)
文摘Dempster-Shafer evidence theory, also called the theory of belief function, is widely used for uncertainty modeling and reasoning. However, when the size and number of focal elements are large, the evidence combination will bring a high computational complexity. To address this issue,various methods have been proposed including the implementation of more efficient combination rules and the simplifications or approximations of Basic Belief Assignments(BBAs). In this paper,a novel principle for approximating a BBA into a simpler one is proposed, which is based on the degree of non-redundancy for focal elements. More non-redundant focal elements are kept in the approximation while more redundant focal elements in the original BBA are removed first. Three types of degree of non-redundancy are defined based on three different definitions of focal element distance, respectively. Two different implementations of this principle for BBA approximations are proposed including a batch and an iterative type. Examples, experiments, comparisons and related analyses are provided to validate proposed approximation approaches.
基金Supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF)funded by the Ministry of Education (NRF2016R1D1A1A02937018)the Bio & Medical Technology Development Program of the NRF, which is funded in part by the Korean government, the Ministry of Science, and ICT (MSIP) (NRF-2017M3A9E2056458)
文摘AIM: To investigate whether the response of a central hexagonal element corresponding to the macular area in conventional multifocal electroretinography(mfERG) tests was the same as that of experimental mfERG using single central hexagonal element stimulation. METHODS: Prospective, observational study. Thirty healthy subjects were included in this study. mfERG recordings were performed according to two protocols: stimulus with 37 hexagonal elements(protocol 1), and stimulus with a single central element created by deactivating the other 36 hexagonal elements(protocol 2). We compared differences between ring 1 parameters in each protocol. RESULTS: In protocol 1, the first positive component(P1) implicit time and P1 amplitude were 37.8±1.8 ms and 6.3±2.7 μV. After single element stimulation(protocol 2), double positive waves appeared. The implicit time and amplitude of P1 were 40.7±2.4 ms(P<0.001) and 9.1±3.3 μV(P=0.001), respectively. The implicit time and amplitude of the second positive component(P2) were 68.0±4.5 ms(P<0.001, compared with P1 in protocol 1) and 12.3±4.7 μV(P<0.001, compared with P1 in protocol 1), respectively. The amplitude of P2 in protocol 2 was about two times higher than that of P1 in protocol 1. CONCLUSION: mfERG responses of a central hexagonal element in a single element stimulation protocol are different from those of multiple element stimulation. The positive wave is more enhanced compared to that of the conventional protocol and it elongated into two wavelets.
