Joobong Song

A User-Centered Approach for Ubiquitous Service Evaluation: An Evaluation Metrics Focused on Human-System Interaction Capability

As the ubiquitous era took off, the interactions between ubiquitous services and users have come to take an important position. So it is necessary to develop new evaluation method that evaluates interactivity with a user-centered perspective. The main objective of this study is the development of user-centered interactivity evaluation metrics of ubiquitous service attributes. For this objective, first, existing ubiquitous service evaluation methodologies are reviewed to define the evaluation attributes for ubiquitous service evaluation. Second, user oriented interactive metrics that can overcome the limitations of those service evaluation methodologies, such as personal service evaluation techniques, usability evaluation techniques and psychometrics based evaluation techniques, are developed. As a validation study, suggested evaluation metrics is utilized to evaluate the u-home service, and priority of each metrics is derived. The suggested evaluation metrics can be used to evaluate the interactivity level of ubiquitous service and identify the potential users and their requirements at the stage of service development.

Relationships of Musculoskeletal Disorder Symptoms and Perceived Workload among Hospital Workers

Objective: This study aims to survey the prevalence of musculoskeletal disorders(MSD) among Korean hospital workers and to analyze the relationship of MSD symptoms and workload perceived by workers. Background: Despite of high exposure to the MSD risk factors and high MSD symptom prevalence among health care workers, there were not enough studies of MSD prevalence among the hospital workers. Method: This study designed a survey based on Nordic questionnaire to obtain MSD symptoms and the degree of four perceived workloads: work repetition, urgency, physical exertion and satisfaction. In this survey, 1,846 workers in a hospital participated. The prevalence of MSD was analyzed for each body part, and MSD cases, which were predetermined in this study, were identified. The relationship between the MSD cases and each perceived workload was analyzed using chi-square test. Results: The pain in the shoulder was the most prevalent among the workers as 52%, and the low back(37%) and leg discomfort(36%) followed. The MSD cases, in which degree of pain was more than severe, were also the most prevalent in the shoulder(13%). Female workers had higher rate of MSD cases than the males. Among the four workload variables, the physical exertion was the statistically related to MSD cases for all the body parts. In addition, the others also had significant relation to MSD cases except one or two body parts. Conclusion: This study found that Korean hospital workers had MSD symptoms mainly in the shoulder, low back and legs in order, and the perceived workload surveyed in this study was highly correlated with MSD symptoms. Application: This study provides another evidence that subjective physical exertion perceived by workers is an important factor to explain MSD cases as same as the objective one.

Performance Analysis of Text Entry with Preferred One Hand using Smart Phone Touch-keyboard

Is performance in smartphone text entry better when using the preferred hand rather than the non-preferred hand? Among right-handed people, is the performance of users who prefer using their left hand in smartphone text entry worse than that of users who prefer using their right hand? The present study addresses these questions. Thirty young male undergraduate students were instructed to type a text message template using a thumb-based QWERTY smartphone with both hands, with only their right hand, and with only their left hand. The completion time and occurrence of errors were measured. All participants were right handed. However, when only one hand is available half of them preferred to use their right hand if they had to enter a text on the smartphone, whereas the other half preferred to use their left hand. In entering a text with only one hand, about 90% of the 15 righthand-preferred participants, and about 70% of the 15 lefthand-preferred participants performed better using their preferred hand than using their nonpreferred hand. However, the performance of the participants who performed better using their left hand was not worse than those who performed better using their right hand in smartphone text entry.

Development of a job rotation scheduling algorithm for minimizing accumulated work load per body parts

BACKGROUND For the successful implementation of job rotation, jobs should be scheduled systematically so that physical workload is evenly distributed with the use of various body parts. However, while the potential benefits are widely recognized by research and industry, there is still a need for a more effective and efficient algorithm that considers multiple work-related factors in job rotation scheduling. OBJECTIVE This study suggests a type of job rotation algorithm that aims to minimize musculoskeletal disorders with the approach of decreasing the overall workload. METHODS Multiple work characteristics are evaluated as inputs to the proposed algorithm. Important factors, such as physical workload on specific body parts, working height, involvement of heavy lifting, and worker characteristics such as physical disorders, are included in the algorithm. For evaluation of the overall workload in a given workplace, an objective function was defined to aggregate the scores from the individual factors. A case study, where the algorithm was applied at a workplace, is presented with an examination on its applicability and effectiveness. RESULTS With the application of the suggested algorithm in case study, the value of the final objective function, which is the weighted sum of the workload in various body parts, decreased by 71.7% when compared to a typical sequential assignment and by 84.9% when compared to a single job assignment, which is doing one job all day. CONCLUSIONS An algorithm was developed using the data from the ergonomic evaluation tool used in the plant and from the known factors related to workload. The algorithm was developed so that it can be efficiently applied with a small amount of required inputs, while covering a wide range of work-related factors. A case study showed that the algorithm was beneficial in determining a job rotation schedule aimed at minimizing workload across body parts.

A Review of Haptic Perception: Focused on Sensation and Application

Objective: The aim of this study is to investigate haptic perception related researches into three perspectives: cutaneous & proprioceptive sensations, active & passive touch, and cognition & emotion, then to identify issues for implementing haptic interactions. Background: Although haptic technologies had improved and become practical, more research on the method of application is still needed to actualize the multimodal interaction technology. Systematical approached to explore haptic perception is required to understand emotional experience and social message, as well as tactile feedback. Method: Content analysis were conducted to analyze trend in haptic related research. Changes in issues and topics were investigated using sensational dimensions and the different contents delivered via tactile perception. Result: The found research opportunities were haptic perception in various body segments and emotion related proprioceptive sensation. Conclusion: Once the mechanism of how users perceives haptic stimuli would help to develop effective haptic interactrion and this study provide insights of what to focus for the future of haptic interaction. Application: This research is expected to provide presence, and emotional response applied by haptic perception to fields such as human-robot, human-device, and telecommunication interaction.

Generating a research keyword structure on human haptic interaction using a social network analysis tool

The field of haptic interaction is inherently multidisciplinary and adopts knowledge from many areas, including robotics, experimental psychology, biology, computer science, systems and control, and others. It is an important first step in research reviewing overall areas of hap-tic related researches, as well as reviewing the specific area of focus. For this purpose, it is important to ensure objective research direction based on the clear and enlightening analysis of the research trends in this field. This study aims to identify the relationship among overall areas of haptic related researches using a network analysis technique. We collected keywords of haptic related researches from several journals and used those as an input for conducting network analysis. Then, we also classified the areas of haptic researches by analyzing the relationship among keywords. From the network analysis, we found that haptic related researches could be classified into two areas; (1) Technology perspectives related to the application of haptic technology and (2) User perspectives related to the perception of haptic sensation. The keyword structure generated from this study is expected to provide basic knowledge on the trend and current status of researches in human haptic inter-action.

Conditions of Applications, Situations and Functions Applicable to Gesture Interface

Objective: This study developed a hierarchy of conditions of applications(devices), situations and functions which are applicable to gesture interface. Background: Gesture interface is one of the promising interfaces for our natural and intuitive interaction with intelligent machines and environments. Although there were many studies related to developing new gesture-based devices and gesture interfaces, it was little known which applications, situations and functions are applicable to gesture interface. Method: This study searched about 120 papers relevant to designing and applying gesture interfaces and vocabulary to find the gesture applicable conditions of applications, situations and functions. The conditions which were extracted from 16 closely-related papers were rearranged, and a hierarchy of them was developed to evaluate the applicability of applications, situations and functions to gesture interface. Results: This study summarized 10, 10 and 6 conditions of applications, situations and functions, respectively. In addition, the gesture applicable condition hierarchy of applications, situation and functions were developed based on the semantic similarity, ordering and serial or parallel relationship among them. Conclusion: This study collected gesture applicable conditions of application, situation and functions, and a hierarchy of them was developed to evaluate the applicability of gesture interface. Application: The gesture applicable conditions and hierarchy can be used in developing a framework and detailed criteria to evaluate applicability of applications situations and functions. Moreover, it can enable for designers of gesture interface and vocabulary to determine applications, situations and functions which are applicable to gesture interface.

A template-based concept generation tool for mobile service development

In order to provide a useful and usable mobile service that offers high value to customers to overcome the usability and performance constraints, this study suggests an user-centered design framework for development of new mobile Internet service. The proposed framework covers user characteristics, context of use, and user interface components of device and network. In a case study, integrated conceptual design process from identification of opportunity to concept evaluation incorporating scenario-based ideation, and CPV-based concept evaluation are proposed and validated. It is expected that the proposed framework can be useful in systemizing the service development process by identifying new service opportunities early at the front end of the process.

A Usability Assessment Metric for Ubiquitous Services: Quantification of the Interactivity Attribute in Inter-personal Services

Objective: The main objective of this study is to propose a user-centered assessment metric for ubiquitous services. Background: As the ubiquitous era took off, the interactions between ubiquitous services and users have come to take an important position. It is essential to conceptualize a new assessment model that considers human-system interaction capability with a user-centered design perspective. Method: The evaluation model for the interactivity of ubiquitous service was approached from the concept of usability and inter-personality of services. As a validation study, suggested assessment metric was utilized to evaluate the u-Home service. Priority weighting of each assessment metric was derived using the quantification type-I analysis. Results: To evaluate interactivity, this study suggested a quantitative metric for user testing performed after classifying the interactivity characteristics to contextualization; ubiquity; user experience; and service capability. Conclusion: This study suggest the metric for the ubiquitous service that are experienced in real life, and introduced the concept of ubiquitous service interactivity. Application: The suggested evaluation metric can be used to evaluate interactivity level of ubiquitous service and identify the potential problem and usability requirements at the early stage of service development.

Affective Characterization of Touch and Look-and-Feel from Multivariate Analysis of Questionnaire Responses

Customers satisfaction is a critical factor to a products success and identifying key affective response factors, which customers mainly perceive, is critical to satisfy customers. This study aims to identify the key affective response factor for the evaluation of passenger car interior material using affective design methods. Related variables of satisfaction consisting of 10 affective response variables associated with look-and-feel and touch feel of a surface material were systematically identified through literature survey, customer reviews, and expert opinions. 30 users and 30 designers evaluated 41 different crash pad samples using a questionnaire survey with 7-point semantic differential scale and 100-point magnitude estimation scale. Based on the survey results, ‘softness’ was identified as the key affective response factor of satisfaction for car crash pad. Also, the relationship between softness and its related engineering variables was identified and modeled. It is expected that the results could suggest the suitable combinations of material properties for the maximum appeal and satisfaction of the user.