数学模型在高校领军人才评审中的应用

教育评估的可靠性决定了评估结果的可信性,影响着教育评估的声誉和发展.结合高校领军人才评审探讨了数学可靠性模型在教育评估中的应用,通过建立数学可靠性模型,计算评审系统的可靠性,并结合可靠性计算结果分析了影响评审系统可靠性的因素.     

Boundary labeling: Models and efficient algorithms for rectangular maps

We introduce boundary labeling, a new model for labeling point sites with large labels. According to the boundary-labeling model, labels are placed around an axis-parallel rectangle that contains the point sites, each label is connected to its corresponding site through a polygonal line called leader, and no two leaders intersect. Although boundary labeling is commonly used, e.g., for technical drawings and illustrations in medical atlases, this problem has not yet been studied in the literature. The problem is interesting in that it is a mixture of a label-placement and a graph-drawing problem.

In this paper we investigate several variants of the boundary-labeling problem. We consider labels of identical or different size, straight-line or rectilinear leaders, fixed or sliding ports for attaching leaders to sites and attaching labels to one, two or all four sides of the bounding rectangle. For any variant of the boundary labeling model, we aim at highly esthetical placements of labels and leaders. We present simple and efficient algorithms that minimize the total leader length or, in the case of rectilinear leaders, the total number of bends.     

Leaders and followers in mutual funds: A dynamic Bayesian approach

This article proposes a dynamic Bayesian framework to analyze the leadership relationships between mutual funds. To this end, a two‐step procedure is proposed. First, a Bayesian rolling window based on the Capital Asset Pricing Model is used to estimate the evolution of mutual funds' market exposure over time. Then, a vector autoregressive (VAR) model is used to analyze the leader‐follower relationship between pair of mutual funds. Several leadership measures are studied. An application to Spanish mutual funds is carried out. In addition, the study examines the determining factors of mutual fund leadership.     

组织系统中领导绩效因素动态分析

组织系统的领导绩效主要取决于行为绩效、成本绩效和组织绩效.在行为绩效保持平稳的状态下,结合投入成本和组织绩效的变化情况,构建连续时间的领导绩效动态模型,以最优领导绩效为目标,应用边际分析方法和最优控制方法,定量分析组织系统的主控因素对于领导绩效的影响度.在组织系统中寻求改进和完善领导绩效的最优路径.     

一种多元杜瓦引线结构和工艺研究

主要介绍了一种散状引线结构形式的探测器用杜瓦结构及密封封接工艺方法。通过寿命跟踪考核、高灵敏度检漏等各项性能检测,表明这一工艺先进可行并已达到实用化推广的水平。     

Randomness and changes of heart rate and respiratory frequency during high altitude mountain ascent without acclimatization

The aim of this study was to detect and compare the changes in the time-frequency and fractal scaling behaviors of heart rate (HR) and respiratory frequency (Rf), recorded simultaneously during a high altitude mountain ascent. The time-frequency analysis was performed using the local cosine4 orthonormal bases of Coifman, Malvar and Meyer, whose spectrum is not redundant as those computed with the short Fourier transform. The fractal scaling behavior was obtained using the detrended fluctuation (DFA) and the wavelet leaders (WL) analysis. Results showed that the high altitude mountain ascent differently affected HR and Rf variability. Rf average values increased (p=0.0003) while HR average values did not change. The scaling variability of HR was altered during the mountain ascent, which was detected by the increasing HR short range DFA exponents with altitude (p<0.03). Rf scaling variability remained unchanged. These differences between HR and Rf alterations were also observed for the local cosine4 power law behavior since power law exponents, in absolute values, increased for HR (p<0.003) while those of Rf did not change. Furthermore, the ratio of low over the whole local spectrum energy of Rf decreased with altitude (p=0.04) in contrast to HR. In most of these HR and Rf analyses, one of the two time series was significantly modified but not both. Moreover, the Rf local cosine4 spectrum had higher entropy compared to HR (p<0.01), the difference between the Rf and the HR entropy increased (p=0.04) during the mountain ascent. In consequence, Rf had more randomness than HR and altitude increased this difference.     

Second-Order Controllability of Multi-Agent Systems with Multiple Leaders

This paper proposes a new second-order continuous-time multi-agent model and analyzes the controllability of second-order multi-agent system with multiple leaders based on the asymmetric topology.This paper considers the more general case:velocity coupling topology is different from location coupling topology.Some sufficient and necessary conditions are presented for the controllability of the system with multiple leaders.In addition,the paper studies the controllability of the system with velocity damping gain.Simulation results are given to illustrate the correctness of theoretical results.     

The control of lightning using lasers: properties of streamers and leaders in the presence of laser-produced ionization

This paper summarizes the research this team has performed over the past few years investigating laboratory electrical breakdown discharges in the presence of a plasma cylinder created by a single ultrashort laser pulse. This work is part of a feasibility study about the control of lightning using laser systems. Our experimental investigations have included discharges (i) in modest (30 cm) air gaps mediated by streamers, and (ii) in large (several meters) ambient air gaps for which the discharge took place through the formation of a leader, the mechanism relevant to large scale natural discharges such as lightning. In order to understand the observations, various physical models have been used, the main results of which are discussed in this paper. To cite this article: F. Vidal et al., C. R. Physique 3 (2002) 1361–1374.     

Flocking in Multi-Agent Systems with Multiple Virtual Leaders Based Only on Position Measurements

Most existing flocking algorithms assume one single virtual leader and rely on information on both relative positions and relative velocities among neighboring agents. In this paper, the problem of controlling a flock of mobile autonomous agents to follow multiple virtual leaders is investigated by using only position information in the sense that agents with the same virtual leader asymptotically attain the same velocity and track the corresponding virtual leader based on only position measurements. A flocking algorithm is proposed under which every agent asymptotically attains its desired velocity, collision between agents can be avoided, and the final tight formation minimizes all agents' global potentials. A simulation example is presented to verify and illustrate the theoretical results.     

Dynamic Robustness of Open-Source Project Knowledge Collaborative Network Based on Opinion Leader Identification

A large amount of semantic content is generated during designer collaboration in open-source projects (OSPs). Based on the characteristics of knowledge collaboration behavior in OSPs, we constructed a directed, weighted, semantic-based knowledge collaborative network. Four social network analysis indexes were created to identify the key opinion leader nodes in the network using the entropy weight and TOPSIS method. Further, three degradation modes were designed for (1) the collaborative behavior of opinion leaders, (2) main knowledge dissemination behavior, and (3) main knowledge contribution behavior. Regarding the degradation model of the collaborative behavior of opinion leaders, we considered the propagation characteristics of opinion leaders to other nodes, and we created a susceptible–infected–removed (SIR) propagation model of the influence of opinion leaders’ behaviors. Finally, based on empirical data from the Local Motors open-source vehicle design community, a dynamic robustness analysis experiment was carried out. The results showed that the robustness of our constructed network varied for different degradation modes: the degradation of the opinion leaders’ collaborative behavior had the lowest robustness; this was followed by the main knowledge dissemination behavior and the main knowledge contribution behavior; the degradation of random behavior had the highest robustness. Our method revealed the influence of the degradation of collaborative behavior of different types of nodes on the robustness of the network. This could be used to formulate the management strategy of the open-source design community, thus promoting the stable development of OSPs.