支持移动多媒体通信中间件的WAP网关

WAP协议是WAP论坛提出的一个开放通信协议;WAP网关进行协议的转换,是移动终端无线接入Internet的枢纽。在简要介绍了无线应用协议后,提出了一个在Linux操作系统平台下运行的WAP网关(数据通信网关)的设计与实现方案,该WAP网关由承载层模块、WAP模块和SMS模块组成,其中详细介绍承载层模块和WAP模块的工作原理,并在实验室环境下对网关进行测试,给出了测试结果。     

Push技术在基于Web的网络管理中的应用

Push技术作为第三代浏览器的核心技术，是一种客户机/服务器之间的通信方式，它采用了公布/订阅/行结构，因而对其应用非常广泛。基于Web的网络管理系统采纳Push技术后，与传统的请求／响应模式相比，效率高，时延低，并且可以节省带宽和CPU时间。而且，对于告警信息的及时上报有重要意义。文中提出了基于Web的TMN管理实例，并在此基础上探讨了应用Push技术实现告警功能的方法。     

金属推型V-带无级变速箱损耗机理仿真部分1:带组摩擦造成的转矩损失

以推型金属带为基体的无级变速箱(CVT)的动力传递效率低于有级变速箱,大家已往认识到采用CVT改进发动机/负荷匹配新取得的燃料经济性的好处有被取消的趋势.本组三篇论文详细阐述了发生在作为第一级用来取得效率改进的带传动中损耗机理的研究.已经进行试验研究了涉及推型金属V-带CVT空载和低载的转矩损失.本第一篇论文述及发生在金属带CVT由于带推块和带间相对运动造成主要转矩损失的新分析方法.本研究考虑到其他研究中的新发现并改进了金属V-带的设计.本文中采用几种不同的试验方法提供的实验数据推荐了转矩损失的数字模型.本组第二篇论文阐述了由于带轮变形的许多附加转矩损失机理.在第三篇论文中阐述了根据本文的发现提出带滑动损失的分析.     

Meta-heuristics for a complex push–pull production system

Hybrid push/pull production systems have received recent attention in the literature. This paper investigates a hybrid push/pull system originating from a foundry. The aim is to determine safety stock and replenishment levels for a large inventory situated at the junction point between component production and assembly operations. Components are produced according to a make-to-stock policy and are received into inventory when completed. Assembled goods are made-to-order, pulling components from the inventory when required. Classical techniques cannot be used in such a complex environment because they are based on invalid assumptions. This study proposes heuristically controlled simulations for attaining good solutions to the problem. Experimental results demonstrate and compare the proposed methods.     

MPEG-7标准及其Pull和Push应用的对比分析

通信与网络技术的飞速发展使得多媒体信息日益增长,传统的基于关键字的检索方式无法满足人们的需要,MPEG-7标准的推出使这一情况出现了转机.文章介绍了MPEG-7标准的主要内容,并对该标准的Pull和Push两类主要应用进行了对比分析,指出了它们的应用领域以及使用时应注意的问题.     

Thumb push forces exertable by free-standing subjects

This study assessed the maximum pushing force that could be exerted by freestanding subjects, using thumbs only, on a small surface located in one of three horizontal positions at nine heights ranging from 13·5 to 169·9 cm above the floor. Each of 102 subjects made nine force exertion trials. Data are given on the cumulative percentages of subjects who could exert various forces at each of the 27 locations. An analysis of variance showed a highly significant effect due to location of the surface and highly significant interactions of location of the surface and trial presentation direction (top-down or bottom-up); of location of the surface and trial presentation pattern; and of location of the surface, trial presentation direction and trial presentation pattern. Maximum forces are exerted at about waist height and are increasingly reduced with increasing distances above and below the optimum location. Right-sided access to pushing surfaces is favoured over left-sided access.     

Physical workload of flight attendants when pushing and pulling trolleys aboard aircraft

The musculoskeletal loads from moving trolleys aboard aircraft were assessed by observation of trolley handling on planes and by physical workload analyses of pushing and pulling of trolleys in a laboratory set up. Trolley handling by a total of 15 female flight attendants was observed on 10 short- and medium-distance flights in different types of aircraft. About 25 selected flight attendants (22 females; 3 males) of five German airlines took part in the laboratory study, which comprised three-dimensional (3D) measurements of posture and hand forces during pushing and pulling of trolleys in a variety of configurations. From the on-flight observations performed, between 150 and 250 trolley movements can be projected for a work shift. The greatest physical workload is to be expected at the beginning of service: The trolleys are fully laden then, and the cabin floor can still be inclined up to 8°, as the aircraft is still climbing, particularly on short-distance flights. The laboratory investigation revealed that the musculoskeletal workload from pushing and pulling depends essentially on the trolley load and on the gradient of the cabin floor. In addition, the degree of stressing depends significantly on the trolley type, mode of handling and personal dexterity. The up/down force component perpendicular to the direction of motion often achieved considerable amplitudes-in some cases equal to or exceeding the force in the direction of movement. The posture analysis demonstrated that pulling forced the flight attendants to adopt ergonomically unfavourable postures such as pronounced flexion of the back, particularly among female subjects. The highest values for flexion of the back occurred while pulling the half-size trolley. The results demonstrate that female flight attendants are likely to overload themselves if they frequently have to move heavily laden trolleys unaided on an inclined cabin floor.

Relevance to industry

On short distance flights, flight attendants have been complaining increasingly of high physical workload from manoeuvring trolleys. On the basis of the presented data airline companies may improve the trolley handling skills of their flight attendances by practical trainings and may ergonomically optimize the general service procedures aboard aircrafts.     

基于Push技术的主动信息服务系统设计与实现

分析了研究主动信息服务系统的现实意义和基于Push技术的主动信息服务系统的所考虑的因素,并利用Push技术设计实现了一个基于图书、杂志、论文等文献的主动信息服务系统。详细介绍了主动信息服务的系统结构、客户端和服务器端的流程、系统实现的主要功能及系统的主要特点。讨论了实现主动信息服务系统的DCOM、XML等关键技术。     

The power of a thumbs-up: Will e-commerce switch to social commerce?

By taking advantage of social networking capabilities, social commerce provides features that encourage customers to share their personal experiences. The popularity of online social networks has driven the purchase decisions of buyers on social commerce sites, but few studies have explored why consumers switch between e-commerce (product-centered) and social (social-centered) commerce sites. In applying the push–pull–mooring model, the objective of this study was to gain an understanding of specifically how push, pull, and mooring factors shape their switching intentions. The findings revealed that push effect, in terms of low transaction efficiency, drives customers away from e-commerce sites, whereas the pull effects, including social presence, social support, social benefit, and self-presentation, attract customers to social commerce sites. Moreover, mooring effects, including conformity and personal experience, strengthened consumers’ behavior in switching between e-commerce and social commerce sites. Besides, conformity was also found to moderate the influences of social presence, social support, social benefit, and efficiency on switching intention, whereas personal experience moderated the effects of social benefit, self-presentation, and efficiency on switching intention. Such an understanding assists online retailers in understanding online shoppers’ switching behaviors, and thus turning social interactions into profits and sales.     

新疆伊宁地浸矿山井场抽注平衡问题的诌议

通过地浸矿山实例,从不同的方面论述了井场抽注平衡控制原理及方法,并对解决生产中出现的抽注不平衡问题提出建议