International Journal of Human-Computer Interaction

Karagiannidis, Charalampos; Koumpis, Adamantios; Stephanidis, Constantine; Georgiou, Andreas C.

doi: 10.1207/s15327590ijhc1004_1pmid: N/A

This article investigates the application of queuing modeling in intelligent multimedia user interfaces (IMUIs). We propose that queuing modeling constitutes an effective means for providing at runtime, assessment information concerning user-computer interaction (UCI) and can thus contribute to runtime adaptation. We present specific queuing systems that model the load posed to the user's sensory channels in IMUIs under different assumptions, and indicative (media-and-modalities allocation) adaptation policies that build on this modeling are exemplified. This article also outlines the implementation of an assessment software module that uses the proposed queuing modeling framework and its subsequent integration into an existing IMUI (in which it is used for the assignment of information to output modalities); both activities were undertaken to practically demonstrate that queuing modeling can be effectively used in IMUIs.

Zhang, Rui; Tamura, Hiroshi; Shibuya, Yu

doi: 10.1207/s15327590ijhc1004_2pmid: N/A

In this study, we examined participants' integration of speech and camera control during message-transfer television conferencing. We obtained participants' free use of speech and camera-control modality when they transmitted 3 types of objects--formed text (FT), mathematical expression (ME), and electronic circuit (EC)-each ranging in size from 1 to 7 elements. Modality use was classified into main-modality use and auxiliary-modality use. Five integration models were proposed based on main-auxiliary combinations. Results indicated that (a) speech was used more frequently for transmitting ME objects, and camera control was used more often for FT and EC objects; (b) speech was gradually replaced by camera control as size increased; (c) when camera control was chosen as main modality, speech was usually also used, as auxiliary modality; and (d) compared to beginners, experienced participants used more speech. A postsession questionnaire was conducted to collect participants' assessment of the correctness, speed, and ease of use of speech and camera control. Camera control had a higher store in total, but speech was thought faster for transmitting FT and M E objects.

Parush, Avraham; Nadir, Ronen; Shtub, Avraham

doi: 10.1207/s15327590ijhc1004_3pmid: N/A

We developed a numerical model for evaluation of graphical user interface (GUI) screens. The model consists of design guidelines concerning screen factors--element size, local density, alignment, and grouping--and produces a complexity score for a given screen. The complexity predictions of the model were examined in a fully factorial experimental design in which GUI screens with all combinations of factors were shown to human users. We measured participants' search times for given elements on all screens, and participants rated their pair-wise preferences of those screens. Overall, very well designed screens resulted in shorter search times and high subjective preference. The combination of poor alignment and poor local density had the strongest adverse effect on search time. Alignment and grouping were found to have more influence on subjective preference. Weights derived from the subjective judgments were introduced into the model and a significant correlation was found between model predictions and search times. We discuss the findings in terms of screen-design implications and in terms of the development and use of numerical models in GUI design and evaluation.

Lantz, Ann

doi: 10.1207/s15327590ijhc1004_4pmid: N/A

A field study was conducted using a questionnaire and interviews concerning how electronic mail (E-mail) is used as a work tool for communication. The questionnaire, distributed electronically within a large organization, showed that employees sending and receiving large numbers of E-mail messages are not the same employees having problems handling E-mail. Managers seem to have problems to a larger extent than members of other workgroups. Interviews were then conducted with 10 employees selected by strata from the questionnaire study. Strata were based on the variables of job category, number of E-mail messages sent and received per day, and E-mail handling problems. The interviews showed that, although employees continually entered the E-mail program, they did not see this action as disruptive of other work activities; instead, they saw it as having a positive effect. E-mail handling problems correlated with the number of messages stored in the inbox (.72). Employees felt a shortage of time for handling E-mail and gave examples of communication problems. Regardless of the number of messages in the inbox and whether employees felt a time shortage, employees had difficulty organizing stored messages within folders and catalogues.

Sutcliffe, Alistair; Rugg, Gordon

doi: 10.1207/s15327590ijhc1004_5pmid: N/A

We describe a taxonomy of error types that builds on work by Reason (1990) and Hollnagel (1993). The taxonomy uses a faceted schema subdivided into layers. Each layer targets a particular analysis task, and a method is proposed leading the assessor through sets of error types at different levels (e.g. cognitive, social, organizational). This allows the causes of failure to be attributed to one or more error types. The method is illustrated with two case studies of diverse failures. The utility of taxonomy analysis in understanding the reasons for failure and risk assessment is discussed.