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Spatiotemporal variations of Chinese lakes and their driving mechanisms since the Last Glacial Maximum:A review and synthesis of lacustrine sediment archives

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Chinese Science Bulletin 2013年第1期58卷 17-31页

作者： shen ji State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography & LimnologyChinese Academy of Sciences

In this article,the author provides the first synthesis and classification of available environment-indicating proxies for lacustrine sediment.A review of spatio-temporal variations in lakes from the Tibetan Plateau,the dry areas of Northwestern China,the Yunnan-Guizhou Plateau and the plains of Eastern China since the LGM is then *** driving mechanism for variations in lake processes and characteristics is also discussed based on various temporal *** author then proposes that future investigations be conducted to:(1) strengthen the study of theoretics and interpretation of environment-indicating proxies,(2) enhance the study of high-resolution time series and spatial variability of lake environment evolution,(3) provide more attention on the influence of human activities on lake environments,and(4) boost construction of the Quaternary lake database of China.

关键词：中国西北地区湖泊沉积物末次盛冰期时空变化驱动机制审查档案环境指示

An algorithm for identifying symmetric variables based on the order eigenvalue matrix

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Frontiers of Information Technology & Electronic Engineering 2017年第10期18卷 1644-1653页

作者： Xiao-hua LI ji-zhong shen Campus Information Center Zhejiang University Hangzhou 310027 China College of lnformation Science & Electronic Engineering Zhejiang University Hangzhou 310027 China

To simplify the process for identifying 12 types of symmetric variables in Boolean functions, we propose a new symmetry detection algorithm based on minterm expansion or the truth table. First, the order eigenvalue matrix based on a truth table is defined according to the symmetry definition of a logic variable. By analyzing the constraint conditions of the order eigenvalue matrix for 12 types of symmetric variables, an algorithm is proposed for identifying symmetric variables of the Boolean function. This algorithm can be applied to identify the symmetric variables of Boolean functions with or without don't-care terms. The proposed method avoids the restriction by the number of logic variables of the graphical method, spectral coefficient methods, and AND-XOR expansion coefficient methods, and solves the problem of completeness in the fast computation method. The algorithm has been implemented in C language and tested on MCNC91 benchmarks. The application results show that, compared with the traditional methods, the new algorithm is an optimal detection method in terms of the applicability of the number of logic variables, the Boolean function including don't-care terms, detection type, and complexity of the identification process.

关键词： Boolean function Symmetric variable Boolean logic algebra system Order eigenvalue matrix Truth table

Numerical Study of Airborne Droplets Propagation Inside a Hospital Consulting Room

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Fluid Dynamics & Materials Processing 2021年第1期17卷 189-200页

作者： Yu Zhou shen ji North China Electric Power University Baoding071000China Affiliated Hospital of Hebei University Baoding071000China

The outbreak of Corona Virus(COVID-19)has spread over a large number of *** virus is typically transported inside liquid droplets produced by human *** a result,doctors operating in the consulting rooms of hospitals are potentially exposed to high *** into account the evaporation of droplets and using a hybrid Eulerian-Lagrangian framework to determine the airflow pattern and corresponding motion of droplets,in the present study,the motion of droplets is investigated with regard to the situation in which doctors check patients in front of their bed.A turbulence model(RNG k-ɛ)is *** purification capacity of different ventilation systems is *** risk of cross-infection between doctors and patients is also evaluated.

关键词： Droplet aerosols numerical simulation infection risk

An algorithm for identifying symmetric variables in the canonical OR-coincidence algebra system

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第12期15卷 1174-1182页

作者： Xiao-hua LI ji-zhong shen Campus Information Center Zhejiang University Department of Information Science & Electronic Engineering Zhejiang University

To simplify the process for identifying 12 types of symmetric variables in the canonical OR-coincidence(COC) algebra system, we propose a new symmetry detection algorithm based on OR-NXOR expansion. By analyzing the relationships between the coefficient matrices of sub-functions and the order coefficient subset matrices based on OR-NXOR expansion around two arbitrary logical variables, the constraint conditions of the order coefficient subset matrices are revealed for 12 types of symmetric variables. Based on the proposed constraints, the algorithm is realized by judging the order characteristic square value matrices. The proposed method avoids the transformation process from OR-NXOR expansion to AND-OR-NOT expansion, or to AND-XOR expansion, and solves the problem of completeness in the dj-map method. The application results show that, compared with traditional methods, the new algorithm is an optimal detection method in terms of applicability of the number of logical variables, detection type, and complexity of the identification process. The algorithm has been implemented in C language and tested on MCNC91 benchmarks. Experimental results show that the proposed algorithm is convenient and efficient.

关键词： Symmetric variable dj-map Canonical OR-coincidence algebra system Boolean function

Power-efficient dual-edge implicit pulse-triggered flip-flop with an embedded clock-gating scheme

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Frontiers of Information Technology & Electronic Engineering 2016年第9期17卷 962-972页

作者： Liang GENG ji-zhong shen Cong-yuan XU College of Information Science & Electronic Engineering Zhejiang University

A novel dual-edge implicit pulse-triggered flip-flop with an embedded clock-gating scheme(DIFF-CGS) is proposed, which employs a transmission-gate-logic(TGL) based clock-gating scheme in the pulse generation stage. This scheme conditionally disables the inverter chain when the input data are kept unchanged, so redundant transitions of delayed clock signals and internal nodes of the latch are all eliminated, leading to low power efficiency. Based on SMIC 65 nm technology, extensive post-layout simulation results show that the proposed DIFF-CGS gains an improvement of 41.39% to 56.21% in terms of power consumption, compared with its counterparts at 10% data-switching activity. Also, full-swing operations in both implicit pulse generation and the static latch improve the robustness of the design. Thus, DIFF-CGS is suitable for low-power applications in very-large-scale integration(VLSI) designs with low data-switching activities.

关键词： Low power Flip-flop Implicit Clock-gating scheme Dual-edge

A submatrix-based P300 brain-computer interface stimulus presentation paradigm

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第6期13卷 452-459页

作者： jin-he SHI ji-zhong shen Yu ji Feng-lei DU Department of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310027China Bio-x Laboratory Department of PhysicsZhejiang UniversityHangzhou 310027China

The P300 event-related potential (ERP), with advantages of high stability and no need for initial training, is one of the most commonly used responses in brain-computer interface (BCI) applications. The row/column paradigm (RCP) that flashes an entire column or row of a visual matrix has been used successfully to help patients to spell words. However, RCP remains subject to errors that slow down communication, such as adjacency-distraction and double-flash errors. In this paper, a new visual stimulus presentation paradigm called the submatrix-based paradigm (SBP) is proposed. SBP divides a 6×6 matrix into several submatrices. Each submatrix flashes in single cell paradigm (SCP) mode and separately performs an ensemble averaging method according to the sequences. The parameter of sequence number is used to improve further the accuracy and information transfer rate (ITR). SBP has advantages of flexibility in division of the matrix and better expansion capability, which were confirmed with different divisions of the 6×6 matrix and expansion to a 6×9 matrix. Stimulation results show that SBP is superior to RCP in performance and user acceptability.

关键词： Brain-computer interface Event-related potentials P300 speller Submatrix-based paradigm

Consensus Proximal Support Vector Machine for Classification Problems with Sparse Solutions

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Journal of the Operations Research Society of China 2014年第1期2卷 57-74页

作者： Yan-Qin Bai Yan-Jun shen Kai-ji shen Department of Mathematics Shanghai UniversityShanghai 200444China

Classification problem is the central problem in machine *** vector machines(SVMs)are supervised learning models with associated learning algorithms and are used for classification in machine *** this paper,we establish two consensus proximal support vector machines(PSVMs)models,based on methods for binary *** first one is to separate the objective functions into individual convex functions by using the number of the sample points of the training *** constraints contain two types of the equations with global variables and local variables corresponding to the consensus points and sample points,*** get more sparse solutions,the second one is l1–l2 consensus PSVMs in which the objective function contains an■1-norm term and an■2-norm term which is responsible for the good classification performance while■1-norm term plays an important role in finding the sparse *** consensus PSVMs are solved by the alternating direction method of ***,they are implemented by the real-world data taken from the University of California,Irvine Machine Learning Repository(UCI Repository)and are compared with the existed models such as■1-PSVM,■p-PSVM,GEPSVM,PSVM,and *** results show that our models outperform others with the classification accuracy and the sparse solutions.

关键词： Classification problems Support vector machine Proximal support vector machine Consensus Alternating direction method of multipliers

Impact of different benthic animals on phosphorus dynamics across the sediment-water interface

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Journal of Environmental Sciences 2010年第11期22卷 1674-1682页

作者： Lei Zhang Xiaozhi Gu Chengxin Fan jingge Shang Qiushi shen Zhaode Wang ji shen State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

As a diagenetic progress, bioturbation influences solute exchange across the sediment-water interface （SWI）. Different benthic animals have various mechanical activities in sediment, thereby they may have different effects on solute exchange across the SWI. This laboratory study examined the impacts of different benthic animals on phosphorus dynamics across the SWI. Tubificid worms and Chironomidae larvae were introduced as model organisms which, based on their mechanical activities, belong to upward-conveyors and gallery-diffusers, respectively. The microcosm simulation study was carried out with a continuous flow culture system, and all sediment, water, and worms and larvae specimens were sampled from Taihu Lake, China. To compare their bioturbation effects, the same biomass （17.1 g wet weight （ww）/m ^2 ） was adopted for worms and larvae. Worms altered no oxygen penetration depth in sediment, while larvae increased the O 2 penetration depth, compared to the control treatment. Their emergence also enhanced sediment O 2 uptake. The oxidation of ferrous iron in pore water produced ferric iron oxyhydroxides that adsorbed soluble reactive phosphorus （SRP） from the overlying water and pore water. Larvae built obviously oxidized tubes with about 2 mm diameter and the maximum length of 6 cm in sediment, and significantly decreased ferrous iron and SRP in the pore water compared to the control and worms treatments. Worms constructed no visually-oxidized galleries in the sediment in contrast to larvae, and they did not significantly alter SRP in the pore water relative to the control treatment. The adsorption of ferric iron oxyhydroxides to SRP caused by worms and larvae inhibited SRP release from sediment. Comparatively, worms inhibited more SRP release than larvae based on the same biomass, as they successively renewed the ferric iron oxyhydroxides rich oxidation layer through their deposition.

关键词： bioturbation oxygen pore water ferrous iron Tubificid worms Chironomidae larvae

DOA estimation based on multi-frequency joint sparse Bayesian learning for passive radar

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Journal of Systems Engineering and Electronics 2022年第5期33卷 1052-1063页

作者： WEN jinfang YI jianxin WAN Xianrong GONG Ziping shen ji School of Electronic Information Wuhan UniversityWuhan 430072China

This paper considers multi-frequency passive radar and develops a multi-frequency joint direction of arrival(DOA)estimation algorithm to improve estimation accuracy and *** developed algorithm exploits the sparsity of targets in the spatial ***,we first extract the required frequency channel data and acquire the snapshot data through a series of preprocessing such as clutter suppression,coherent integration,beamforming,and constant false alarm rate(CFAR)***,based on the framework of sparse Bayesian learning,the target’s DOA is estimated by jointly extracting the multi-frequency data via evidence *** results show that the developed algorithm has better estimation accuracy and resolution than other existing multi-frequency DOA estimation algorithms,especially under the scenarios of low signalto-noise ratio(SNR)and small ***,the effectiveness is verified by the field experimental data of a multi-frequency FM-based passive radar.

关键词： multi-frequency passive radar DOA estimation sparse Bayesian learning small snapshot low signal-to-noise ratio(SNR)