基于动态冲击试验的通勤类飞机座椅符合性验证技术

国产某型民用通勤类飞机为了取得欧洲航空安全局(EASA)型号合格证,机上座椅需进行设计更改并补充进行应急着陆情况下的动态要求符合性验证.通过对适航条款及相应标准的解读,研究了基于动态试验的航空座椅动态要求适航验证技术,其主要包括座椅动态性能基本要求、试验构型及工况筛选、试验规划、合格判据和试验结果分析等内容.结果表明,该型机旅客座椅满足适航规章对座椅的动态性能要求.该项旅客座椅动态性能试验的成功为型号取得EASA型号合格证奠定了良好的基础,该型飞机也即将成为第一个取得欧洲型号合格证的国产飞机.     

中华人民共和国成立70年来生态文明体制变迁的内在逻辑与实践启示

中华人民共和国成立以来,中国共产党带领中国人民不断探索实践生态文明建设。随着人民环境偏好的增强,中国的生态文明体制不断变迁以满足人民日益增长的美好生态环境需要。通过对中国环境管理机构、环境保护政策变迁历程的梳理,可以探析其变迁的内在逻辑和动力机制。中国的生态文明体制变迁始终坚持以人民为中心的发展思想,以适应人民群众环境偏好变化为逻辑起点,并不断通过体制改革来提高环境治理效率和改善环境治理效果。中华人民共和国成立以来生态文明体制的变迁为新时代生态文明建设奠定了基础、指明了方向,在未来建设美丽中国过程中要坚持以人民为中心的发展思想以满足人民环境偏好变化、完善生态文明制度建设为增强环境治理的效果和效率提供保障、以综合治理的思路构建中国特色社会主义生态文明建设的治理体系。     

Market impact: a systematic study of the high frequency options market

This paper deals with a fundamental subject that has seldom been addressed in recent years, that of market impact in the options market. Our analysis is based on a proprietary database of metaorders—large orders that are split into smaller pieces before being sent to the market—on one of the main Asian markets. In line with our previous work on the equity market [Said, E., Bel Hadj Ayed, A., Husson, A. and Abergel, F., Market impact: A systematic study of limit orders. Mark. Microstruct. Liq., 2018, 3(3&4), 1850008.], we propose an algorithmic approach to identify metaorders, based on some implied volatility parameters, the at the money forward volatility and at the money forward skew. In both cases, we obtain results similar to the now well-understood equity market: Square-Root Law, Fair Pricing Condition and Market Impact Dynamics.     

Periodic strategies in optimal execution with multiplicative price impact

We study the optimal execution problem with multiplicative price impact in algorithmic trading, when an agent holds an initial position of shares of a financial asset. The interselling decision times are modeled by the arrival times of a Poisson process. The criterion to be optimized consists in maximizing the expected net present value of the gains of the agent, and it is proved that an optimal strategy has a barrier form, depending only on the number of shares left and the level of the asset price.     

Mandatory IFRS adoption and management forecasts: The impact of enforcement changes

We examine how concurrent enforcement changes affect the positive relationship between mandatory IFRS adoption and firms’ voluntary disclosure. We show that the increase in the issuance of management forecasts after IFRS adoption is smaller for firms from IFRS-mandating countries with concurrent enforcement changes than for those from countries without such changes. We find no difference in the increase of forecast informativeness between firms from IFRS-mandating countries without concurrent enforcement changes and firms from non-IFRS-mandating countries; however, firms domiciled in IFRS-mandating countries with concurrent enforcement changes exhibit a significantly smaller increase in forecast informativeness. Our findings suggest that better IFRS enforcement distinctly weakens (strengthens) the positive effect of IFRS adoption on voluntary (mandatory) disclosure.     

辽西北地区农业干旱危险性评价与区划

[目的]开展农业干旱危险性评价与区划研究,为辽宁省西北地区农业防旱抗灾工作提供科学依据。[方法]文章根据联合国国际减灾战略署(ISDR)对农业干旱危险性的定义,分析了构成研究区作物干旱危险性的致灾因子和孕灾环境因子,采用层次分析法确定了各因子的权重,构建了研究区农业干旱危险性评价指标和模型。以2009年为例,通过利用降雨、土壤、农业生产类型及地形等数据计算了辽西北地区农业干旱危险性评价指数,利用自然间断点法分级干旱危险性评价指数,并借助GIS技术,绘制研究区农业干旱危险性等级区划图。[结果] 2009年作物生长期间研究区农业干旱危险性由高到低排列为:朝阳市葫芦岛市锦州市阜新市铁岭市沈阳市。[结论]辽西北地区农业干旱危险性等级区的划分,能够帮助政府管理部门为面临干旱威胁不同的区域建立适当的防灾方法和有效的应急预案。     

The equity impacts of bus rapid transit: A review of the evidence and implications for sustainable transport

The paper offers an analysis of empirical evidence on the equity impacts of operational Bus Rapid Transit (BRT) systems in the Global South. The focus is on vertical equity, i.e. whether BRT systems achieve progressive benefits for poorer segments of the population. Findings from Africa, Asia, and Latin America all suggest that BRT does offer significant benefits to low-income groups, in terms of travel time and cost savings, access enhancement, and safety and health benefits. However benefits are often skewed toward medium-income users and thus less progressive than they might be. Two primary reasons for this are insufficient spatial coverage and inappropriate fare policies. While many features of BRT potentially allow it to deliver pro-poor outcomes, such outcomes only materialize if BRT implementers pay specific and sustained attention to equity. The paper identifies key issues that need to be addressed to steer BRT implementation toward more socially sustainable outcomes—including better integration with other transit, paratransit, and nonmotorized transport services, and with the housing sector.     

The Impact of the Implementation of Technology Education on In-Service Teacher Education in South Africa (Impact of Technology Education in the RSA)

In this article the impact of technology education, as a new learning area (subject) in the curriculum, on in-service teacher education in South Africa is described in order to ascertain the extent of the impact. The research on which this article is based draws on a variety of experiences and observations in the field at grassroots level (in particular an outreach project in rural communities). The envisaged impact of technology education on South African schools, communities, teacher educators and teachers, the range of in-service teacher education that is required, and the impacts in urban and rural areas are discussed. Finally a number of concluding remarks are made about the extent of the impact of the inclusion of technology education in the new National Curriculum Statement and whether the situation has changed since the implementation of a pilot technology education project in 1998. This revised version was published online in July 2006 with corrections to the Cover Date.     

Rural traffic management: The Burrator Reservoir experiment

The introduction of traffic management schemes has been one response of the National Parks to the problem of ever-increasing car-borne visitors and the consequent damage caused to the rural environment. By reviewing these schemes and by determining and explaining attitudes towards one particular traffic management experiment, the paper aims to deduce lessons for future policy. The analysis, based on two visitor surveys, suggests that the likelihood of success is improved when schemes are integrated, containing both ‘carrot’ and ‘stick’ elements. Since public perceptions are also found to be pivotal to its success, appropriate marketing of a scheme is vital. The paper concludes, however, that to achieve the fundamental objective of greater accessibility with less mobility, a more wide-ranging marketing effort is required intended to engender a sea change in attitude towards both the car and public transport.     

从功能出发进行对外汉语语法教学的研究与实践

该文系统地总结了作者进行对外汉语语法教学的实践经验——从功能出发进行对外汉语语法教学，具体从三个方面入手：一、语法教学和词汇教学相结合；二、句法结构和语义结构相结合；三、语法知识和语言环境相结合。