论我国地理信息产业、人才现状与存在问题

在论述我国地理信息产业与从业人才现状基础上,分析了产业发展与人才培养中所存在的问题,着重对高校GIS人才培养提出了自己的看法与见解。     

论知识经济与高校人才培养

简要介绍了知识经济及其特征 ,论述我国高等教育面临挑战的基础上 ,对我国高等教育如何迎接知识经济的挑战 ,培养高素质人才提出了自己的看法     

使命、特色与高校党的建设——兼论高校党建与学科建设

以广东海洋大学为例,阐述了大学肩负的时代使命是高校办学价值目标的终极追求,是大学理念的外化形式,突出特色、提高办学水平是完成使命的根本途径,加强党的建设是实现学校办学目标的根本保证。     

Generalized force vectors for multi‐mode pushover analysis

A generalized pushover analysis (GPA) procedure is developed for estimating the inelastic seismic response of structures under earthquake ground excitations. The procedure comprises applying different generalized force vectors separately to the structure in an incremental form with increasing amplitude until a prescribed seismic demand is attained for each generalized force vector. A generalized force vector is expressed as a combination of modal forces, and simulates the instantaneous force distribution acting on the system when a given response parameter reaches its maximum value during dynamic response to a seismic excitation. While any response parameter can be selected arbitrarily, generalized force vectors in the presented study are derived for maximum interstory drift parameters. The maximum value of any other response parameter is then obtained from the envelope of GPAs results. Each nonlinear static analysis under a generalized force vector activates the entire multi‐degree of freedom effects simultaneously. Accordingly, inelastic actions develop in members with the contribution of all ‘instantaneous modes’ in the nonlinear response range. Target seismic demands for interstory drifts at the selected stories are calculated from the associated drift expressions. The implementation of the proposed GPA is simpler compared with nonlinear response history analysis, whereas it is less demanding in computational effort when compared with several multi‐mode adaptive nonlinear static procedures. Moreover, it does not suffer from the statistical combination of inelastic modal responses obtained separately. The results obtained from building frames have demonstrated that GPA is successful in estimating maximum member deformations and member forces with reference to the response history analysis. When the response is linear elastic, GPA and response spectrum analysis produce identical results. Copyright © 2010 John Wiley & Sons, Ltd.     

A rationale for accrediting GIScience programs

The accreditation of GIS programs was first proposed more than 25 years ago as a means of encouraging consistency in instructional content and learning outcomes across many new GIS programs being developed at U.S. colleges and universities. However, in lieu of a peer review system to evaluate the quality of instruction, the GIS community focused instead on certification programs for recognizing and rewarding competency and professionalism among persons already in the workforce. With hundreds of colleges and universities now offering formal programs in GIScience ranging from certificates to undergraduate and graduate degrees, it may be an appropriate time reconsider rewards associated with accreditation. This article argues that accreditation can benefit institutions, students, and GIScience employers by directing attention to “upstream” and formative elements in the preparation of entry-level GIScience professionals that can potentially complement “downstream” and summative programs for recognizing experienced GIScience professionals such as certification. Along with providing detail about the implementation and administration of accreditation, we explore accreditation processes in surveying and engineering as possible pathways for accrediting academic GIScience programs.     

Mechanisms to limit higher mode effects in a controlled rocking steel frame. 1: Concept,modelling, and low‐amplitude shake table testing

Controlled rocking steel frames have been proposed as an efficient way to avoid the structural damage and residual deformations that are expected in conventional seismic force resisting systems. Although the base rocking response is intended to limit the force demands, higher mode effects can amplify member design forces, reducing the viability of the system. This paper suggests that seismic forces may be limited more effectively by providing multiple force‐limiting mechanisms. Two techniques are proposed: detailing one or more rocking joints above the base rocking joint and providing a self‐centring energy dissipative (SCED) brace at one or more levels. These concepts are applied to the design of an eight‐storey prototype structure and a shake table model at 30% scale. A simple numerical model that was used as a design tool is in good agreement with frequency characterization and low‐amplitude seismic tests of the shake table model, particularly when multiple force‐limiting mechanisms are active. These results suggest that the proposed mechanisms can enable better capacity design by reducing the variability of peak seismic force demands without causing excessive displacements. Similar results are expected for other systems that rely on a single location of concentrated nonlinearity to limit peak seismic loads. Copyright © 2012 John Wiley & Sons, Ltd.     

The cause of unproportionately large higher mode contributions in the inelastic seismic responses of high‐rise core‐wall buildings

In the conventional seismic design of high‐rise reinforced concrete core‐wall buildings, the design demands such as design shear and bending moment in the core wall are typically determined by the response spectrum analysis procedure, and a plastic hinge is allowed to form at the wall base to limit the seismic demands. In this study, it is demonstrated by using a 40‐story core‐wall building that this conventional approach could lead to an unsafe design where the true demands—the maximum inelastic seismic demands induced by the maximum considered earthquake—could be several times greater than the design demands and be unproportionately dominated by higher vibration modes. To identify the cause of this problem, the true demands are decomposed into individual modal contributions by using the uncoupled modal response history analysis procedure. The results show that the true demands contributed by the first mode are reasonably close to the first‐mode design demands, while those contributed by other higher modes are much higher than the corresponding modal design demands. The flexural yielding in the plastic hinge at the wall base can effectively suppress the seismic demands of the first mode. For other higher modes, however, a similar yielding mechanism is either not fully mobilized or not mobilized at all, resulting in unexpectedly large contributions from higher modes. This finding suggests several possible approaches to improve the seismic design and to suppress the seismic demands of high‐rise core‐wall buildings. Copyright © 2012 John Wiley & Sons, Ltd.     

基于多模态分离的面波谱分析方法

面波频谱分析法(SASW) 作为一种横向分辨率较高的瑞雷面波勘探方法, 由于计算得到的基阶面波频散曲线存在较大误差以及无法获得高阶模式频散曲线而在应用中受到限制.通过应用Fourier变换方法(FT法) 分离提取面波各模态数据, 进而对分离后的各模态数据利用SASW法计算频散曲线.通过模型实例分析得出: (1) 利用SASW计算基阶面波频散曲线时必须分离得到基阶面波数据, 然后计算才能得到正确的结果; (2) 基于多模态分离的SASW法可以计算得到面波高阶模式的频散曲线.      

Development of deformable connection for earthquake‐resistant buildings to reduce floor accelerations and force responses

This paper presents the development of a deformable connection that is used to connect each floor system of the flexible gravity load resisting system (GLRS) with the stiff lateral force resisting system (LFRS) of an earthquake‐resistant building. It is shown that the deformable connection acts as a seismic response modification device, which limits the lateral forces transferred from each floor to the LFRS and allows relative motion between the GLRS and LFRS. In addition, the floor accelerations and the LFRS story shears related to the higher‐mode responses are reduced. The dispersion of peak responses is also significantly reduced. Numerical simulations of the earthquake response of a 12‐story reinforced concrete shear wall example building with deformable connections are used to define an approximate feasible design space for the deformable connection. The responses of the example building model with deformable connections and the example building model with rigid‐elastic connections are compared. Two configurations of the deformable connection are studied. In one configuration, a buckling restrained brace is used as the limited‐strength load‐carrying hysteretic component of the deformable connection, and in the other configuration, a friction device is used. Low damping laminated rubber bearings are used in both configurations to ensure the out‐of‐plane stability of the LFRS and to provide post‐elastic stiffness to the deformable connection. Important experimental results from full‐scale tests of the deformable connections are presented and used to calibrate numerical models of the connections. Copyright © 2016 John Wiley & Sons, Ltd.     

天气雷达探测遭电子干扰分析与解决途径

随着电子技术的不断发展,各种无线发射装置的广泛应用,无线接收设备尤其是高灵敏度的雷达都有可能遭遇各种意想不到的电子干扰.通过分析经历过的多起雷达受扰事件,挑选包括气象部门雷达相互间的同频干扰,与军用雷达相互间的同频干扰,微波接力站和民用超高频数传机对天气雷达的干扰等几起具有代表性的典型个例,就其发生现象、检判过程、产生的原因、实际解决办法和最终结果以及带来的相关启示做了一些分析探讨,可为从事技术保障的同行提供有益的借鉴.