感知Web服务质量的测度研究

Developing Metrics for Estimating Perceived Web Service Quality

确定各种网络服务或应用服务的SLA(服务等级协约)参数是实施SLA管理的前提之一。基于Web服务的实现机理以及用户浏览习惯,定义了两个易于测量的Web服务内在性能测度:平均响应延迟和交付速率。在两个实验中,分别在不同时间不同上网条件下访问特定Web站点一段时间,在客户方被动测量相关Web流量、计算上述两测度值,同时记下用户当时感知服务质量的主观评价值。对两次观测数据分别进行线性回归分析,发现两测度相结合确实能够反映用户访问Web站点时的感知服务质量。

To enforce SLA(Service Level Agreement) management, SLA metrics for network services or application services must be established in advance. In this paper two metrics for Web service intrinsic performance, average response delay and delivery speed are defined taking both implementation mechanism of Web applications and user access behavior into account. In either of two experiments, to calculate above two metrics, Web traffic traces for a specified Web site are recorded at client-side; meanwhile the user-perceived service quality of the Web site need be evaluated subjectively. Linear regress analysis based on two sets of observation data shows that the two metrics together can be used in a linear regression function to objectively estimate user-perceived Web quality of service.