What you get is what you see: revisiting the evaluator effect in usability tests

Usability evaluation is essential to user-centred design; yet, evaluators who analyse the same usability test sessions have been found to identify substantially different sets of usability problems. We revisit this evaluator effect by having 19 experienced usability professionals analyse video-recorded test sessions with five users. Nine participants analysed moderated sessions; 10 participants analysed unmoderated sessions. For the moderated sessions, participants reported an average of 33% of the problems reported by all nine of these participants and 50% of the subset of problems reported as critical or serious by at least one participant. For the unmoderated sessions, the percentages were 32% and 40%. Thus, the evaluator effect was similar for moderated and unmoderated sessions, and it was substantial for the full set of problems and still present for the most severe problems. In addition, participants disagreed in their severity ratings. As much as 24% (moderated) and 30% (unmoderated) of the problems reported by multiple participants were rated as critical by one participant and minor by another. The majority of the participants perceived an evaluator effect when merging their individual findings into group evaluations. We discuss reasons for the evaluator effect and recommend ways of managing it.     

Evidence for non-site-isolation in ZSM-5 from ion-exchange and catalytic studies

Ion exchange of HZSM-5 samples with alkali metal cations, using metal chloride solutions, results in partially exchanged zeolites, MHZSM-5, M = Li, Na, K or Cs. The degree of exchange is found to increase with increasing ionic radius of the cations. The catalytic properties of the alkalized zeolites were evaluated using the reaction conditions under which the catalytic activity of the HZSM-5 samples in terms of n-hexane cracking is proportional to the aluminium content. From the residual catalytic activity exhibited by the Na-, K- and CsHZSM-5 samples it is concluded that each of the larger Na⁺, K⁺ and Cs⁺ ions is influencing more than one AlO ₄ ^– tetrahedron, implying that the aluminium sites in ZSM-5 are not isolated. The ion-exchange results are then interpreted in terms of non-isolated aluminium sites. The ion-exchange and catalytic properties of the zeolites as a function of aluminium content are also discussed.     

软件测试工具分析及其应用探讨

结合实践探讨了在现有生产软件的中小型企业中,如何将软件测试与软件开发相结合,使软件测试管理的质量得以提升。介绍了一些目前常用的软件测试工具及测试管理工具,对软件测试管理中应注意到的80:20问题进行阐述分析,提出对测试管理中可能存在的风险可采取一些方法来应对。实践证明,使用全程软件测试管理对解决测试管理工作中存在的问题有很大帮助。     

试谈计算机软件测试管理的应用

计算机的软件测试是软件工程构成部分之一,同时软件测试也是检验软件开发人员及软件产品是否合格的重要凭据。就软件测试管理系统活动及应用两个方面的内容进行研究,并对管理工具的存在进行简单的介绍。     

基于约束关系的变强度组合测试用例集生成算法

针对传统的变强度组合测试方法对系统中各因素之间的约束关系考虑不足,从而可能导致测试用例冗余的问题,论文提出了一种基于one-Test-at-a-time策略的变强度组合测试用例集生成算法,该算法充分考虑了因素间的约束关系,从而在一定程度上减少了测试用例集的规模。最后通过实验验证了算法的可行性和有效性。     

Entity Framework数据访问性能优化的几种方法

Entity Framework一般通过LINQ代码或lambda表达式自动生成SQL语句,开发效率很高,然而使用时如果不注意会引来性能问题。通过对不同方法使用Entity Framework进行比较,提出Entity Framework数据访问性能优化的几种方法,包括更新数据时使用无跟踪查询、通过附加数据修改和删除数据、合理使用ToList()和FirstOrDefault()、合理使用预先加载。经过性能测试,这些方法是有效的。     

基于MEMS声传感器的圆柱壳体振动陀螺振型检测技术

振动陀螺谐振子振型一般采用激光进行非接触式测量,这种方法存在设备成本高、操作复杂、效率低等问题,因此,提出了一种基于MEMS声传感器的圆柱壳体振动陀螺谐振子振型测试方法。该方法利用体积小,指向性高的MEMS声传感器对谐振子振动声场进行高分辨率测量,获得精确的谐振子振动分布情况,建立了谐振子声波测试实验系统,进行了测试实验,并与激光测振仪的测量结果进行比对。实验结果表明,该测试系统具有较高的振型测量精度。这种测试方法成本低,操作简便,测量精度高,可以实现谐振子振型的高精度快速测量,为后续的谐振子修形及陀螺控制提供重要基础。     

试验温度和停放时间对胶料加工性能的影响

研究试验温度和停放时间对胶料加工性能的影响。结果表明，试验温度对胶料的门尼粘度、门尼焦烧时间和硫化特性均有一定影响。门尼粘度测定的试验温度选择100℃；门尼焦烧时间测定的试验温度一般选120℃，SBR胶料可提高至130℃左右，以缩短试验时间；硫化特性测定的试验温度一般选185℃。试验前模腔达到规定温度后再保持15min，以使转子与模腔温度一致。胶料停放时间应控制在2h左右。     

改进的APRIORI算法在试卷系统数据挖掘中的应用

本文通过对数据挖掘技术的研究,采用关联规则法对学生答题数据进行分析,并在关联规则使用中采用改进型的Apriori算法进行运算,构建高频集,并对于高分学生和低分学生的试卷进行了加权处理,使得高频集中的试题在知识点和难度上的关联更加突出,便于在自动组卷时更科学地评价试卷.     

软件安全性检测技术综述

该文阐述了网络软件安全检测的重要性,介绍了现有的主要检测方法,包括形式化安全测试、基于模型的安全功能测试、语法测试、基于故障注入的安全测试、基于属性的测试、模糊测试、基于风险的安全性测试、基于故障树的安全性测试以及基于渗透的安全性测试。