论国家助学贷款中的大学生诚信隐忧及其对策

围绕党的十八大精神和《中共中央关于全面深化改革若干重大问题的决定》中提出的"大力促进教育公平,健全家庭经济困难学生资助体系",以社会主义核心价值观为指导,通过对国家助学贷款中大学生诚信缺失现状及原因的分析,借鉴发达国家的有效模式,探讨国家助学贷款中大学生诚信体系建设的新机制、新思路。     

A dam-breach erosion model: II. Application

In Part I, the earthen dam breach erosion was analyzed. To this end, the BEED (breach erosion of earthfill dams) model was modified and extended. In this paper, Part II of the series, the extended BEED model is applied to three historical cases: South Fork Dam, Buffalo Creek Dam, and Teton Dam. The testing before it can be used for forecast purposes. A sensitivity analysis of the model to its parameters shows that the model is very sensitive to friction factors; Chenzy's for breach erosion, and Manning's for flood routing.     

Surplus equivalence of leveled commitment contracts

In automated negotiation systems consisting of self-interested agents, contracts have traditionally been binding. Leveled commitment contracts—i.e., contracts where each party can decommit by paying a predetermined penalty—were recently shown to improve expected social welfare even if agents decommit strategically in Nash equilibrium. Such contracts differ based on whether agents have to declare their decommitting decisions sequentially or simultaneously, and whether or not agents have to pay the penalties if both decommit. For a given contract, these mechanisms lead to different decommitting thresholds, probabilities, and expected social welfare. However, this paper shows that each of these mechanisms leads to the same social welfare when the contract price and penalties are optimized for each mechanism separately. Our derivations allow agents to construct optimal leveled commitment contracts. We show that such integrative bargaining does not hinder distributive bargaining: the surplus can be divided arbitrarily (as long as each agent benefits), e.g., equally, without compromising optimality. Nonuniqueness questions are answered. We also show that surplus equivalence ceases to hold if agents are not risk neutral.     

The Impact of Specific Job Stressors on Psychological Contract Breach and Violation

This study investigated whether environmental stressors predict perceptions of psychological contract breach and associated feelings of violation in employees from a large manufacturing organization. It was proposed that increasing levels of job stress as a result of changes in the employment context may account for the rising incidence of perceived contract breach. The results suggest that breach and violation are more likely when employees are experiencing role conflict, perceive a lack of career progression, and perceive a lack of control over work. Further, control was found to moderate the relationship between stress and breach. This study has important practical implications, suggesting ways in which organizations may be able to reduce the likelihood of psychological contract breach and violation.     

Information security breaches and IT security investments: Impacts on competitors

In current business climate, a firm’s information systems security is no longer independent from the industry’s broader security environment. A question arises, then, whether stock market values reflect the interdependence of security breaches and investments. In this paper, we used the event study methodology to investigate how a firm’s security breaches and IT security investments influence its competitors. We collected and reviewed 118 information security breaches and 98 IT security investment announcements from 2010 to 2017. We found substantial evidence supporting our hypothesis that information security breaches do, indeed, have a competition effect: when one firm is breached, its competitors have opportunities to absorb market power. For the IT security investment announcements, however, we observed the positive externalities, or contagion effect, in play: market investors feel that the security investments made by one firm increase the security level of the entire network, and hence, competitors also get benefits. Additionally, we found that the competition effect was higher when the breaches occurred after the preceding security investments than when there were no preceding investments before the breaches.     

Best and worst-case coverage problems for arbitrary paths in wireless sensor networks

The path-based coverage of a wireless sensor network is to analyze how well the network covers the sensor field in terms of paths. Known results prior to this research, however, considered only a single source–destination pair and thus do not provide a global outlook at the given network but a local feature for the given source–destination pair. In this paper, we propose a new coverage measure of sensor networks that considers arbitrary source–destination pairs. Our novel measure naturally extends the previous concept of the best and the worst-case path-based coverage to evaluate the coverage of a given network from a global point of view, taking arbitrary paths into account.In terms of the present coverage measure, we pose the evaluation and the deployment problems for give a network; the former is to evaluate the new coverage measure of a given sensor network, and the latter is to find an optimal placement of k additional sensor nodes to improve the coverage for a given positive integer k. We present several algorithms that are either centralized or localized that solve the problems with theoretical proofs and simulation results, thus showing that our algorithms are efficient and easy to implement in practice while the quality of their outputs is guaranteed by formal proofs. For the purpose, we show an interesting relation between the present coverage measure and a certain quantity of a point set, called the bottleneck, which has been relatively well studied in other disciplines such as computational geometry and operations research.     

钢筋混凝土方形烟囱的控爆拆除

本文根据方形烟囱的受力特点,结合实例,分析了烟囱的爆破特点与方法。     

Landslide dams triggered by the Wenchuan Earthquake,Sichuan Province,south west China

At 14:28 (Beijing time) on 12 May 2008, the catastrophic Ms 8.0 Wenchuan earthquake occurred just west of the Sichuan basin, China, causing severe damage and numerous casualties. It also triggered a large number of landslides, rock avalanches, debris flows etc. Some of the landslides formed natural dams in the rivers, with the potential secondary hazard of subsequent flooding. Through the interpretation of a series of aerial photographs and satellite images, 256 landslide dams were identified, although because of limited access, relatively detailed data were available for only 32. The paper presents statistical analyzes of the distribution, classification, characteristics, and hazard evaluation of these 32 dams. A case study of the 2.04 × 10⁷ m³ Tangjiashan landslide dam and the emergency mitigation measures undertaken is discussed.     

Breach模型与River2D模型在土石坝溃坝中的耦合分析

Breach是一个用于对土石坝进行溃坝分析以获取时间和流量关系的模型,River2D是一个用于模拟下游洪泛区内溃坝洪水演进以获取全要素风险信息的模型。两个模型的耦合分析在保护水库的安全及管理水库的运行方面有着预防的作用。     

Using PTV through an embankment breach channel

Particle tracking velocimetry was used to determine for the first time the surface velocities upstream, downstream, and through experimental embankment dam breach channels at all stages of breach development. A series of experimental tests was performed, which used varying initial breach geometry. The measurements were made using Styrofoam surface tracking particles and three different video camera angles to obtain 3-dimensional velocity measurements, which were calculated using ArcGIS. Space-time contour maps of velocity were then interpolated for each of the breach scenarios. A maximum surface flow velocity of 2.1 m/s, corresponding to 21 m/s at prototype scale, was measured at the downstream end of the breach channel near the time to peak for the breach outflow. The surface velocities were also converted to average velocities and used in conjunction with breach flow measurements to determine the depth of flow through the breach channel and to make estimates of the sub-aqueous breach geometry. Estimates of flow depth through the breach were used to compare measured outflow results with those determined analytically using the broad-crested weir equation.