We present a new method to identify navigation related Web usability problems based on comparing actual and anticipated usage patterns. The actual usage patterns can be extracted from Web server logs routinely recorded for operational websites by first processing the log data to identify users, user sessions, and user task-oriented transactions, and then applying a usage mining algorithm to discover patterns among actual usage paths. The anticipated usage, including information about both the path and time required for user-oriented tasks, is captured by our ideal user interactive path models constructed by cognitive experts based on their cognition of user behavior.
The comparison is performed via the mechanism of test MY SQL for checking results and identifying user navigation difficulties. The deviation data produced from this comparison can help us discover usability issues and suggest corrective actions to improve usability. A software tool was developed to automate a significant part of the activities involved. With an experiment on a small service-oriented website, we identified usability problems, which were cross-validated by domain experts, and quantified usability improvement by the higher task success rate and lower time and effort for given tasks after suggested corrections were implemented. This case study provides an initial validation of the applicability and effectiveness of our method.
As the World Wide Web becomes prevalent today, building and ensuring easy-to-use Web systems is becoming a core competency for business survival. Usability is defined as the effectiveness, efficiency, and satisfaction with which specific users can complete specific tasks in a particular environment. Three basic Web design principles, i.e., structural firmness, functional convenience, and presentational delight, were identified to help improve users’ online experience. Structural firmness relates primarily to the characteristics that influence the website security and performance. Functional convenience refers to the availability of convenient characteristics, such as a site’s ease of use and ease of navigation, that help users’ interaction with the interface. Presentational delight refers to the website characteristics that stimulate users’ senses. Usability engineering provides methods for measuring usability and for addressing usability issues. Heuristic evaluation by experts and user-centered testing are typically used to identify usability issues and to ensure satisfactory usability.
However, significant challenges exist, including 1) accuracy of problem identification due to false alarms common in expert evaluation 2) unrealistic evaluation of usability due to differences between the testing environment and the actual usage environment, and 3) increased cost due to the prolonged evolution and maintenance cycles typical for many Web applications. On the other hand, log data routinely kept at Web servers represent actual usage. Such data have been used for usage-based testing and quality assurance and also for understanding user behavior and guiding user interface design.
Server-side logs can be automatically generated by Web servers, with each entry corresponding to a user request. By analyzing these logs, Web workload was characterized and used to suggest performance enhancements for Internet Web servers. Because of the vastly uneven Web traffic, massive user population, and diverse usage environment, coverage-based testing is insufficient to ensure the quality of Web applications. Therefore, server-side logs have been used to construct Web usage models for usage-based Web testing or to automatically generate test cases accordingly to improve test efficiency.
WEB USABILITY PROBE: A TOOL FOR SUPPORTING REMOTE USABILITY EVALUATION OF WEB SITES
PUBLICATION: Human-Computer Interaction—INTERACT 2011. New York, NY, USA: Springer, 2011,pp. 349–357.
AUTHORS: T. Carta, F. Patern`o, and V. F. D. Santana
SUPPORTING ACTIVITY MODELLING FROM ACTIVITY TRACES
PUBLICATION: Expert Syst., vol. 29, no. 3, pp. 261–275, 2012.
AUTHORS: O. L. Georgeon, A. Mille, T. Bellet, B. Mathern, and F. E. Ritter,
We present a new method and tool for activity modelling through qualitative sequential data analysis. In particular, we address the question of constructing a symbolic abstract representation of an activity from an activity trace. We use knowledge engineering techniques to help the analyst build ontology of the activity, that is, a set of symbols and hierarchical semantics that supports the construction of activity models. The ontology construction is pragmatic, evolutionist and driven by the analyst in accordance with their modelling goals and their research questions. Our tool helps the analyst define transformation rules to process the raw trace into abstract traces based on the ontology. The analyst visualizes the abstract traces and iteratively tests the ontology, the transformation rules and the visualization format to confirm the models of activity. With this tool and this method, we found innovative ways to represent a car-driving activity at different levels of abstraction from activity traces collected from an instrumented vehicle. As examples, we report two new strategies of lane changing on motorways that we have found and modelled with this approach.
TOOLS FOR REMOTE USABILITY EVALUATION OF WEB APPLICATIONS THROUGH BROWSER LOGS AND TASK MODELS
PUBLICATION: Behavior Res.Methods, Instrum., Comput., vol. 35, no. 3, pp. 369–378, 2003
AUTHORS: L. Paganelli and F. Patern`o,
The dissemination of Web applications is extensive and still growing. The great penetration of Web sites raises a number of challenges for usability evaluators. Video-based analysis can be rather expensive and may provide limited results. In this article, we discuss what information can be provided by automatic tools able to process the information contained in browser logs and task models. To this end, we present a tool that can be used to compare log files of user behavior with the task model representing the actual Web site design, in order to identify where users’ interactions deviate from those envisioned by the system design.
Previous studies usability has long been addressed and discussed, when people navigate the Web they often encounter a number of usability issues. This is also due to the fact that Web surfers often decide on the spur of the moment what to do and whether to continue to navigate in a Web site. Usability evaluation is thus an important phase in the deployment of Web applications. For this purpose automatic tools are very useful to gather larger amount of usability data and support their analysis.
Remote evaluation implies that users and evaluators are separated in time and/or space. This is important in order to analyse users in their daily environments and decreases the costs of the evaluation without requiring the use of specific laboratories and asking the users to move. In addition, tools for remote Web usability evaluation should be sufficiently general so that they can be used to analyse user behaviour even when using various browsers or applications developed using different toolkits. We prefer logging on the client-side in order to be able to capture any user-generated events, which can provide useful hints regarding possible usability problems.
Existing approaches have been used to support usability evaluation. An example was WebRemUsine, which was a tool for remote usability evaluation of Web applications through browser logs and task models. Propp and Frorbrig have used task models for supporting usability evaluation of a different type of application: cooperative behaviour of people interacting in smart environments. A different use of models is in the authors discuss how task models can enhance visualization of the usability test log. In our case we do not require the effort of developing models to apply our tool. We only require that the designer provides an example of optimal use associated with each of the relevant tasks. The tool will then compare the logs with the actual use with the optimal log in order to identify deviations, which may indicate potential usability problems.
Web navigate used a logger to collect data from a user session test on a Web interface prototype running on a PDA simulator in order to evaluate different types of Web navigation tools and identify the best one for small display devices.
Users were asked to find the answer to specific questions using different types of navigation tools to move from one page to another. A database was used to store users’ actions, but they logged only the answer given by the user to each specific question. Moreover they stored separately every term searched by the user by means of the internal search tool.
Client-side data encounters different challenges regarding the identification of the elements that users are interacting with, how to manage element identification when the page is changed dynamically, how to manage data logging when users are going from one page to another, amongst others. The following are some of the solutions we adopted in order to deal with these issues.
We propose a new method to identify navigation related usability problems by comparing Web usage patterns extracted from server logs against anticipated usage represented in some cognitive user models (RQ2). Fig. 1 shows the architecture of our method. It includes three major modules: Usage Pattern Extraction, IUIP Modeling, and Usability Problem Identification. First, we extract actual navigation paths from server logs and discover patterns for some typical events. In parallel, we construct IUIP models for the same events. IUIP models are based on the cognition of user behavior and can represent anticipated paths for specific user-oriented tasks.
Our IUIP models are based on the cognitive models surveyed in Section II, particularly the ACT-R model. Due to the complexity of ACT-R model development and the low-level rule based programming language it relies on we constructed our own cognitive architecture and supporting tool based on the ideas from ACT-R. In general, the user behavior patterns can be traced with a sequence of states and transitions. Our IUIP consists of a number of states and transitions. For a particular goal, a sequence of related operation rules can be specified for a series of transitions. Our IUIP model specifies both the path and the benchmark interactive time (no more than a maximum time) for some specific states (pages). The benchmark time can first be specified based on general rules for common types of Web pages. Humans usually try to complete their tasks in the most efficient manner by attempting to maximize their returns while minimizing the cost.
Typically, experts and novices will have different task performance. Novices need to learn task specific knowledge while performing the task, but experts can complete the task in the most efficient manner. Based on this cognitive mechanism, IUIP models our method is cost-effective. It would be particularly valuable in the two common situations, where an adequate number of actual users cannot be involved in testing and cognitive experts are in short supply. Server logs in our method represent real users’ operations in natural working conditions, and our IUIP models injected with human behavior cognition represent part of cognitive experts’ work. We are currently integrating these modeling and analysis tools into a tool suite that supports measurement, analysis, and overall quality improvement for Web applications.
1) Logical deviation calculation:
- a) When the path choice anticipated by the IUIP model is available but not selected, a single deviation is counted.
- b) Sum up all the above deviations over all the selected user transactions for each page.
2) Temporal deviation calculation:
- a) When a user spends more time at a specific page than the benchmark specified for the corresponding state in the IUIP model, a single deviation is counted.
- b) Sum up all the above deviations over all the selected user transactions for each page.
The successive pages related to furniture categories are grouped into a dashed box. The pages with deviations and the unanticipated follow up pages below them are marked with solid rectangular boxes. Those unanticipated follow up pages will not be used themselves for deviation calculations to avoid double counting.
HARDWARE & SOFTWARE REQUIREMENTS:
v Processor – Pentium –IV
- Speed – 1 GHz
- RAM – 256 MB (min)
- Hard Disk – 20 GB
- Floppy Drive – 44 MB
- Key Board – Standard Windows Keyboard
- Mouse – Two or Three Button Mouse
- Monitor – SVGA
- Operating System : Windows XP or Win7
- Front End : JAVA JDK 1.7
- Back End : MYSQL Server
- Server : Apache Tomact Server
- Script : JSP Script
- Document : MS-Office 2007