Quantifying the different contributions of co-authors is a challenging task, and existing methods often rely on the assumption that orders of author bylines reflect the contribution of co-authors. Byline-based approaches, however, render them incompatible to alphabetically-ordered bylines where authors are ordered by names, not by their contributions. The authors proposed a citation-based author contribution measure citeRatio independent of byline orders while capturing the importance of the first and last authors.

In recent years, as the amount of data grows, personal information management has become essential as well as challenging for everyday lives. Tagging, an alternative or complement to classifying into tree-structured directories, allows users to classify a single information item in multiple categories. Due to its flexibility, tagging system has become popular and a number of studies have been conducted. Most of the previous research investigated the quality of tags with various tools such as questionnaires. However, the actual usage behavior of tag-based browsing and retrieval of stored information has rarely been studied. In this study, we examined the effects of tag attributes on the user behavior in browsing self-tagged documents under personal information management settings.Three attributes, tag commonness, tag frequency and tag position, were identified. A controlled experiment with tasks of tagging and retrieval to trace users’ behavior revealed that the tags with higher tag commonness, higher tag frequency, and lower tag position were more likely to be used. The tags with lower tag commonness and lower tag frequency helped users recognize a desired document among a list of candidates. Among the three attributes, tag position was found the most influential. The findings of this study are expected to enhance the understanding of the quality tags and help information designers in building an effective tagging environment.

As a mobile phone has various advanced functionalities or features, usability issues are increasingly challenging. Due to the particular characteristics of a mobile phone, typical usability evaluation methods and heuristics, most of which are relevant to a software system, might not effectively be applied to a mobile phone. Another point to consider is that usability evaluation activities should help designers find usability problems easily and produce better design solutions. To support usability practitioners of the mobile phone industry, we propose a framework for evaluating the usability of a mobile phone, based on a multi-level, hierarchical model of usability factors, in an analytic way. The model was developed on the basis of a set of collected usability problems and our previous study on a conceptual framework for identifying usability impact factors. It has multi-abstraction levels, each of which considers the usability of a mobile phone from a particular perspective. As there are goal-means relationships between adjacent levels, a range of usability issues can be interpreted in a holistic as well as diagnostic way. Another advantage is that it supports two different types of evaluation approaches: task-based and interface-based. To support both evaluation approaches, we developed four sets of checklists, each of which is concerned, respectively, with task-based evaluation and three different interface types: Logical User Interface (LUI), Physical User Interface (PUI) and Graphical User Interface (GUI). The proposed framework specifies an approach to quantifying usability so that several usability aspects are collectively measured to give a single score with the use of the checklists. A small case study was conducted in order to examine the applicability of the framework and to identify the aspects of the framework to be improved. It showed that it could be a useful tool for evaluating the usability of a mobile phone. Based on the case study, we improved the framework in order that usability practitioners can use it more easily and consistently.

The characteristics of the behaviors of home- service robots are different from those of other intelligent systems. Based on these characteristics, we developed a task model that can both support meaningful interactions and improve task performance. The task model is able to generate the robot's diverse actions and aid its interaction management. A decision/interaction model was established to decide autonomy of decision problems that are embedded on the task model. When Interactions with humans are required, it also manages timing of the interactions. We demonstrated the applicability of the developed system with a computer simulation.

This study aims to establish a model-based approach for user interface design that simultaneously considers the system’s information hierarchy, users’ task procedure knowledge, and system interfaces. The approach is based on a framework that contains multiple interaction models to express both system elements and users’ knowledge. The framework evaluates system interface through the interaction between user’s knowledge on interface, task procedure and information structure perceived by the user in the system. The interface is evaluated by its contribution to the users’ task performance and system navigation. These three factors were defined as design factors that affect users’ task performance. Through the crosscheck process of models, the relation between information, interface, and task procedure is calculated into combined difficulty index (CDI) that expresses the difficulty of a system interface that users would experience during the use of system. A user test was conducted for the validation of the CDI. The difficulties of the interface of a mobile healthcare system were predicted with the CDI, and the predictions were compared with the experimental results, where the users’ performance showed consistence with the prediction.

Model-based interaction design is a promising approach to the problem of building sophisticated interactive systems. Although many models and model-based design methods have been proposed, in practice their effectiveness has tended to be limited to solving fragmented design problems. One factor that has diminished the effectiveness of previous approaches has been their inability to integrate the various models used for different aspects of the overall design problem. This paper proposes a novel approach for combining a structural model and a functional model for complicated interaction design. Formal correspondence between the models is defined and a conversion process to transform from one model to the other and vice versa is introduced. The functional model, OCD, is an efficient technique for representing task procedures, while the structural model, statechart, is well suited to representing system behavior. The usability needs and system requirements are introduced into the design process through either representation. Then, the constraints formed by a decision in a model can be seen by the designer in the other model through transformation. The possibility of automatic conversion between the models warrants the consistence between the models through the design process even when the models should continually evolve.

A qualitative reasoning scheme with explicit temporal expression is presented. Its aim is to develop a possible solution for the fundamental problem of temporal reasoning and ambiguity rather than to refine the existing techniques for a specific domain. The proposed system represents the system behavior in the form of a partially ordered network. Time intervals may be defined in terms of relative lengths in a quantity space. Such explicit description of temporal quantities helps reduce ambiguity in qualitative simulation. An independent quantity space management system organizes the qualitative reasoning about physical and temporal quantities.>