A group oriented cryptosystem for the vector space access structure was proposed. This cryptosystem adopts self-certified public keys. It allows the participants of an authorized subset to cooperatively access an encr...A group oriented cryptosystem for the vector space access structure was proposed. This cryptosystem adopts self-certified public keys. It allows the participants of an authorized subset to cooperatively access an encrypted message. All data delivered in the cryptosystem are public. Therefore it does not need a partial decrypting results combiner and any secure communication channel. The security of the group oriented cryptosystem is based on the intractability of the discrete log problem and difficulty of factoring large integers. The suspected attacks can not break it.展开更多
Discontinuities in rock masses critically impact the stability and safety of underground engineering.Mainstream discontinuities identificationmethods,which rely on normal vector estimation and clustering algorithms,su...Discontinuities in rock masses critically impact the stability and safety of underground engineering.Mainstream discontinuities identificationmethods,which rely on normal vector estimation and clustering algorithms,suffer from accuracy degradation,omission of critical discontinuities when orientation density is unevenly distributed,and need manual intervention.To overcome these limitations,this paper introduces a novel discontinuities identificationmethod based on geometric feature analysis of rock mass.By analyzing spatial distribution variability of point cloud and integrating an adaptive region growing algorithm,the method accurately detects independent discontinuities under complex geological conditions.Given that rock mass orientations typically follow a Fisher distribution,an adaptive hierarchical clustering algorithm based on statistical analysis is employed to automatically determine the optimal number of structural sets,eliminating the need for preset clusters or thresholds inherent in traditional methods.The proposed approach effectively handles diverse rock mass shapes and sizes,leveraging both local and global geometric features to minimize noise interference.Experimental validation on three real-world rock mass models,alongside comparisons with three conventional directional clustering algorithms,demonstrates superior accuracy and robustness in identifying optimal discontinuity sets.The proposed method offers a reliable and efficienttool for discontinuities detection and grouping in underground engineering,significantlyenhancing design and construction outcomes.展开更多
Trimethylchlorosilane was used as a stereoselective reagent to determine the e or a orientation of 3-hydroxyl group of some steroids by chemical ionization mass spectrometry.
The Jiangsu Orient International Group is based in Wujiang City, Jiangsu Province. Its predecessor, the Wujiang Yarn-dyed Fabric Weaving Mill, was set up in 1977. Set up in 1991 was the Yuanfang Garment Co. Ltd, a Sino-
The Orient International Group has now officially been approved by the State Council as an experiment for a comprehensive corporation. This is one of the large enterprise groups approved as experiment for a comprehens...The Orient International Group has now officially been approved by the State Council as an experiment for a comprehensive corporation. This is one of the large enterprise groups approved as experiment for a comprehensive corporation, only second to the China National Chemicals Import and Export Corporation, and the first one locally.展开更多
Reporter: What is the development goal for Shanghai World Expo (Group) Co., Ltd.? Mr. Chen Xianjin: Our goal lies in 2 aspects: one is how to hold a successful world expo; the other is how to achieve World Expo Group ...Reporter: What is the development goal for Shanghai World Expo (Group) Co., Ltd.? Mr. Chen Xianjin: Our goal lies in 2 aspects: one is how to hold a successful world expo; the other is how to achieve World Expo Group into a 1st-class enterprise in China with most competitiveness. The 2 goals take overall development of Shanghai into consideration, while Shanghai展开更多
The objective of study in the paper was to analyze advantages, disadvantages, opportunities and threats of development of pig healthy agriculture in China, using systematic analysis and SWOT strategic analysis, as wel...The objective of study in the paper was to analyze advantages, disadvantages, opportunities and threats of development of pig healthy agriculture in China, using systematic analysis and SWOT strategic analysis, as well as to show severe diseases, abnormal fluctuation, misplaced way and versatile environment confronted by pig breeding in China. The paper establishes ＂double-hug mode＂, from which pig breeding industry transforms and upgrades to modern breeding industry. Combing with the designed multi-party cooperation mechanism of advantageous regions, urban sale areas and group corporations, it sets up three paths for development of pig healthy agriculture in China, i.e., strategic paths of advantageous regions, urban sale areas and group corporations oriented, with an attempt to provide strategic path reference for transformation and upgrading of pig breeding in China and mode reference for breakthrough of development strategy for pig healthy industry.展开更多
Discontinuity is critical for strength,deformability,and permeability of rock mass.Set information is one of the essential discontinuity characteristics and is usually accessed by orientation grouping.Traditional meth...Discontinuity is critical for strength,deformability,and permeability of rock mass.Set information is one of the essential discontinuity characteristics and is usually accessed by orientation grouping.Traditional methods of identifying optimal discontinuity set numbers are usually achieved by clustering validity indexes,which mainly relies on the aggregation and dispersion of clusters and leads to the inaccuracy and instability of evaluation.This paper proposes a new method of Fisher mixed evaluation(FME)to identify optimal group numbers of rock mass discontinuity orientation.In FME,orientation distribution is regarded as the superposition of Fisher mixed distributions.Optimal grouping results are identified by considering the fitting accuracy of Fisher mixed distributions,the probability monopoly and central location significance of independent Fisher centers.A Halley-Expectation-Maximization(EM)algorithm is derived to achieve an automatic fitting of Fisher mixed distribution.Three real rock discontinuity models combined with three orientation clustering algorithms are adopted for discontinuity grouping.Four clustering validity indexes are used to automatically identify optimal group numbers for comparison.The results show that FME is more accurate and robust than the other clustering validity indexes in optimal discontinuity group number identification for different rock models and orientation clustering algorithms.展开更多
文摘A group oriented cryptosystem for the vector space access structure was proposed. This cryptosystem adopts self-certified public keys. It allows the participants of an authorized subset to cooperatively access an encrypted message. All data delivered in the cryptosystem are public. Therefore it does not need a partial decrypting results combiner and any secure communication channel. The security of the group oriented cryptosystem is based on the intractability of the discrete log problem and difficulty of factoring large integers. The suspected attacks can not break it.
基金the National Key Research and Development Program of China(Grant No.2023YFC3009400).
文摘Discontinuities in rock masses critically impact the stability and safety of underground engineering.Mainstream discontinuities identificationmethods,which rely on normal vector estimation and clustering algorithms,suffer from accuracy degradation,omission of critical discontinuities when orientation density is unevenly distributed,and need manual intervention.To overcome these limitations,this paper introduces a novel discontinuities identificationmethod based on geometric feature analysis of rock mass.By analyzing spatial distribution variability of point cloud and integrating an adaptive region growing algorithm,the method accurately detects independent discontinuities under complex geological conditions.Given that rock mass orientations typically follow a Fisher distribution,an adaptive hierarchical clustering algorithm based on statistical analysis is employed to automatically determine the optimal number of structural sets,eliminating the need for preset clusters or thresholds inherent in traditional methods.The proposed approach effectively handles diverse rock mass shapes and sizes,leveraging both local and global geometric features to minimize noise interference.Experimental validation on three real-world rock mass models,alongside comparisons with three conventional directional clustering algorithms,demonstrates superior accuracy and robustness in identifying optimal discontinuity sets.The proposed method offers a reliable and efficienttool for discontinuities detection and grouping in underground engineering,significantlyenhancing design and construction outcomes.
文摘Trimethylchlorosilane was used as a stereoselective reagent to determine the e or a orientation of 3-hydroxyl group of some steroids by chemical ionization mass spectrometry.
文摘The Jiangsu Orient International Group is based in Wujiang City, Jiangsu Province. Its predecessor, the Wujiang Yarn-dyed Fabric Weaving Mill, was set up in 1977. Set up in 1991 was the Yuanfang Garment Co. Ltd, a Sino-
文摘The Orient International Group has now officially been approved by the State Council as an experiment for a comprehensive corporation. This is one of the large enterprise groups approved as experiment for a comprehensive corporation, only second to the China National Chemicals Import and Export Corporation, and the first one locally.
文摘Reporter: What is the development goal for Shanghai World Expo (Group) Co., Ltd.? Mr. Chen Xianjin: Our goal lies in 2 aspects: one is how to hold a successful world expo; the other is how to achieve World Expo Group into a 1st-class enterprise in China with most competitiveness. The 2 goals take overall development of Shanghai into consideration, while Shanghai
基金Acknowledgments The authors thank for the support by National Natural Science Foundation of China ＂The Study of Benefits Safeguards of Healthy Pig Breeding Industry and Exemplified Promotion Mechanism＂ （70873125） and by the collaborative project of Scientific Research and Graduate Training of Beijing Municipal Education Commission （Grant 201502911110426）.
文摘The objective of study in the paper was to analyze advantages, disadvantages, opportunities and threats of development of pig healthy agriculture in China, using systematic analysis and SWOT strategic analysis, as well as to show severe diseases, abnormal fluctuation, misplaced way and versatile environment confronted by pig breeding in China. The paper establishes ＂double-hug mode＂, from which pig breeding industry transforms and upgrades to modern breeding industry. Combing with the designed multi-party cooperation mechanism of advantageous regions, urban sale areas and group corporations, it sets up three paths for development of pig healthy agriculture in China, i.e., strategic paths of advantageous regions, urban sale areas and group corporations oriented, with an attempt to provide strategic path reference for transformation and upgrading of pig breeding in China and mode reference for breakthrough of development strategy for pig healthy industry.
基金supported by the National Natural Science Foundation of China(Grant Nos.42272338,41827807 and 41902275)Shanghai Sailing Program(Grant No.18YF1424400)+7 种基金Joint Fund for Basic Research of High-speed Railway of National Natural Science Foundation of China,China Railway Corporation(U1934212)China State Railway Group Co.,Ltd.(P2019G038)Department of Transportation of Zhejiang Province(202213)China Railway First Survey and Design Institute Group Co.,Ltd.(19-21-1,2022KY53ZD(CYH)-10)China Railway Tunnel Group Co.,Ltd.(CZ02-02-08)PowChina Hebei Transportation Highway Investment Development Co.,Ltd.(TH-201908)Sichuan Railway Investment Group Co.,Ltd.(SRIG2019GG0004)The Science and Technology major program of Guizhou Province[2018]3011.
文摘Discontinuity is critical for strength,deformability,and permeability of rock mass.Set information is one of the essential discontinuity characteristics and is usually accessed by orientation grouping.Traditional methods of identifying optimal discontinuity set numbers are usually achieved by clustering validity indexes,which mainly relies on the aggregation and dispersion of clusters and leads to the inaccuracy and instability of evaluation.This paper proposes a new method of Fisher mixed evaluation(FME)to identify optimal group numbers of rock mass discontinuity orientation.In FME,orientation distribution is regarded as the superposition of Fisher mixed distributions.Optimal grouping results are identified by considering the fitting accuracy of Fisher mixed distributions,the probability monopoly and central location significance of independent Fisher centers.A Halley-Expectation-Maximization(EM)algorithm is derived to achieve an automatic fitting of Fisher mixed distribution.Three real rock discontinuity models combined with three orientation clustering algorithms are adopted for discontinuity grouping.Four clustering validity indexes are used to automatically identify optimal group numbers for comparison.The results show that FME is more accurate and robust than the other clustering validity indexes in optimal discontinuity group number identification for different rock models and orientation clustering algorithms.
