摘要：Structural analysis of steel frames is typically performed using beam elements. Since these elements are unable to explicitly capture the local buckling behavior of steel cross-sections, traditional steel design specifications use the concept of cross-section classification to determine the extent to which the strength and deformation capacity of a cross-section are affected by local buckling. The use of plastic design methods are restricted to Class 1 cross-sections, which possess sufficient rotation capacity for plastic hinges to develop and a collapse mechanism to form. local buckling prevents the development of plastic hinges with such rotation capacity for cross-sections of higher classes and, unless computationally demanding shell elements are used, elastic analysis is required. However, this article demonstrates that local buckling can be mimicked effectively in beam elements by incorporating the continuous strength method (CSM) strain limits into the analysis. Furthermore, by performing an advanced analysis that accounts for both geometric and material nonlinearities, no additional design checks are required. The positive influence of the strain hardening observed in stocky cross-sections can also be harnessed, provided a suitably accurate stress–strain relationship is adopted;a quad-linear material model for hot-rolled steels is described for this purpose. The CSM strain limits allow cross-sections of all slenderness to be analyzed in a consistent advanced analysis framework and to benefit from the appropriate level of load redistribution. The proposed approach is applied herein to individual members, continuous beams, and frames, and is shown to bring significant benefits in terms of accuracy and consistency over current steel design specifications.

摘要：随着互联网产业和技术的不断发展,各型各色的基于互联网页面的Web应用也成为人们获取信息、娱乐、服务等的重要途径之一。这就对各个Web应用系统的性能提出了高要求。文中对Web性能优化技术中的local Storage的存储性能进行了研究与分析。针对技术本身存在的性能问题,设计了一系列实验来进行验证,探究解决性能问题的方案。实验发现,对local Storage存储空间频繁访问,会对系统性能造成较大影响。针对实验所暴露的local Storage所存在的性能问题,文中设计了对local Storage存储性能改进的方案,并根据该方案,对local Storage的存储结构进行了改进。以解决因对local Storage存储空间频繁访问所造成的系统效率降低。

摘要：随着嵌入式系统技术迅速发展,PowerPC处理器以其实时性好、运算能力强和接口丰富等特点被广泛应用于嵌入式设计中。PowerPC+FPGA架构为PowerPC嵌入式系统最常用架构,两者之间通过local Bus总线相连,实现对外功能扩展。local Bus为并行地址数据复用总线,地址锁存时机的选择对local Bus总线稳定工作尤为重要。文章基于PowerPC8640处理器通过设计和测试验证给出了其local Bus地址锁存同步设计和异步设计的方法。

摘要：为构成高性能的数据库,磁盘阵列的活用是很有必要的。其中尤为重要的是实现磁盘阵列之间负载的均衡。为此,设计了网络磁盘结构系统,该系统在磁盘阵列高负载的情况下也能够进行动态的负载均衡,并且具有优良的耐故障性。对于网络磁盘结构构成要素中的local Migration Manager(LMM)进行了设计。列举出了LMM连接的Main Bus上传送的信息,定义了信息形式,信息的传送与Bus的宽度相符呈分割进行;在LMM的设计方法中定义了LMM的内部数据结构;在此基础上,制作了LMM的算法。

摘要：群智创新社区是信息化条件下一种新的创新载体和媒介,可以为企业开展产品研发活动提供大量创新创意。为了更好地管理群智创新社区和用户,选取local Motors社区作为研究对象,通过对不同用户行为进行数据采集与分析,运用聚类分析,从用户创新能力的角度,对不同创新能力的用户进行识别和划分,得出4种不同创新能力的用户类型,并对每种类型的用户进行了社区影响作用分析。科研成果既可丰富相关理论研究,也可为社区管理者提供实践方略与运营建议,有效提升社区管理水平与创新效率。

摘要：介绍了一款嵌入式处理器模块的设计,该模块采用龙芯2号增强型处理器,并针对嵌入式应用特点自行设计了北桥。模块体积为100mm×66mm,板载FLASH和DDR内存,可独立引导系统内核工作,利用串口作为系统终端。实际使用可作为嵌入式系统子卡使用,板载了32位PCI总线接口和32位local BUS接口,用户可根据实际需求来进行系统功能扩展和二次开发。介绍了该模块设计中的关键技术以及系统扩展方法。

摘要：The design of a stall-regulated wind turbine to achieve a maximum annual energy output is still a formidable task for engineers. The design could be carried out using an average wind speed together with a standard statistical distribution such as a Weibull with k = 2.0. In this study a more elaborated design will be attempted by also considering the statistical bias as a design criterion. The wind data used in this study were collected from three areas of the Lamtakong weather station in Nakhonratchasima Provice, the Khaokoh weather station in Phetchaboon and the Sirindhorn dam weather station in Ubonratchathani, Thailand. The objective is to design a best aerodynamic configurations for the blade (chord, twist and pitch) using the same airfoil as that of NREL Phase VI wind turbine. Such design is carried out at a design wind speed point. Wind turbine blades were optimized for both maximum annual energy production and minimum cost of energy using a method that take into account aerodynamic and structural considerations. The work will be carried out by the program “SuWiTStat” which was developed by the authors and based on BEM Theory (Blade Element Momentum). Another side issue is the credibility of the Weibull statistic in representing the real wind measurement. This study uses a regression analysis to determine this issue.

摘要：This paper presents quiet zone design using ultrasonic transducers for local active control in pure tone diffuse fields. Most of researches in local active noise control used conventional loudspeakers for the secondary sources to produce quiet zones. Recently ultrasonic transducers have been used for the secondary sources to control the plane wave in active noise control. However there is no research related to active noise control in diffuse fields using ultrasonic transducers. Therefore this study uses ultrasonic transducers for the secondary sources to control the diffuse fields. The quiet zone produced using ultrasonic transducers in single tone diffuse fields has been analyzed through simulations in this work. The results showed that quiet zones created using ultrasonic transducers were larger than those created using conventional loudspeakers. This is due to the fact that the audible sound pressure produced by the ultrasonic transducers decays slowly with the distance. Therefore the secondary field created by an ultrasonic transducer could fit the primary field better and the larger zone of quiet could be obtained using the ultrasonic transducer. Also the audible sound produced by the ultrasonic transducers is directional;therefore the sound pressure amplification outside the quiet zones was lower.

摘要：To examine the REDD+ (Reducing Emissions from Deforestation and Forest Degradation) program as an alternative to an oil palm plantation in West Kutai district of East Kalimantan, we determined the profitability of land use and REDD+, and the land use preferences and practices of the local people, as well as their participation in and preferences for forestry programs. Our findings indicate the following: 1) the profitability of an oil palm plantation was higher than that from other land uses and the REDD+ program;2) the local preferences for land uses were mostly consistent with the profitability of the land uses, except for oil palm plantation due to non-financial concerns;3) the local people combined each land use in accordance with their various needs;and 4) the local people were interested in a Forest and Land Rehabilitation (RHL) program in nonforestry zones. Considering these evidences, an improved RHL program based on an intensive agroforestry system and a conservation-based REDD+ program based on existing customary conservation forest management by the local people are proposed. Given the high opportunity cost and the low preference for an oil palm plantation, designing the REDD+ program by paying attention to the non-financial benefits for a community is a way forward. To enhance the non-financial benefits, it is important to take into consideration local preferences and livelihood activities in designing the REDD+ program. This study also implies the need for a reconsideration of the position of participation of local people in the safeguards of REDD+.

摘要：视频图像火灾探测技术因其探测效率高、响应速度快等优点而被广泛应用,但普通摄像机无法拍摄零照度(黑暗)甚至低照度环境下的烟雾图像。而火灾发生时往往先产生烟雾,若能实现火灾早期的烟气探测将有利于预防火灾规模的扩大和人员财产的损失。利用红外摄像机结合红外发射灯来成像以完成对火灾的探测,具体探测过程为:首先利用中值滤波去除原始灰度图像中的噪声;其次利用三帧差分法提取烟雾前景;然后通过local Binary Patterns与灰度共生矩阵分别获取烟雾纹理的局部和统计特征;最后将烟雾纹理特征输入Fisher分类器以识别烟雾与非烟雾(如水汽、飞尘等),并及时发出报警信号。设计有无环境风和人为干扰环境下的烟雾与水汽试验,利用烟雾运动的不规则性与扩散性、图像的Gabor特征、LBP尺度验证所用纹理特征。结果表明,从分类正确率和响应时间看,在低照度环境下所用纹理特征优于其他烟雾特征法。另外,通过调节相机与火源之间的距离,可得到应用于实际工程的红外摄像机最佳安装距离。