AHFE Open AccessHuman Factors and Ergonomics In Design
Table of Contents
A Two-Phase Asynchronous–Synchronous Online Co-Design Method for Facilitating Multistakeholder Participation in Healthcare Technology
Multistakeholder co-design is widely used in healthcare technology development to surface diverse viewpoints and support alignment across stakeholder groups. However, healthcare co-design faces persistent challenges: providers’ fragmented schedules limit sustained participation, provider-receiver authority asymmetries can shape whose input is taken up, and receivers from vulnerable or stigmatized groups may hesitate to engage in visible real-time discussion. We propose a low-cost, two-phase asynchronous-synchronous online co-design method designed to reduce these participation barriers. The method separates (1) asynchronous perspective articulation, which enables stakeholders to contribute at their own pace, from (2) synchronous perspective exchange, which relies on limited real-time interaction to clarify tensions and negotiate trade-offs. A researcher-mediated transition connects the phases by translating distributed inputs into de-attributed, negotiable discussion prompts. We illustrate the approach through a chatbot co-design case for pre-exposure prophylaxis (PrEP) care involving PrEP navigators and clients, using widely available tools (Google Sites, Sheets, and Meet). The case shows how asynchronous engagement surfaces divergent expectations about the chatbot’s scope and communication style, and structured prompts support focused negotiation in dyadic sessions. We conclude by discussing how the method mitigates authority effects when synchronous exchange remains essential, and how the structure can be iterated across cycles as new questions emerge.
Cai-Ling Wang, Yuan-Chi Tseng
Open Access
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Conference Proceedings
Mapping Experiential Values of Office Chairs: Insights from Qualitative Observations
As Activity-Based Working (ABW) becomes standard, office chairs play a vital role in supporting productivity. However, many advanced functions remain underutilized due to unintuitive design, suggesting a gap between chair features and user understanding. This study aims to identify the experiential values workers seek in office chairs to establish more effective design guidelines. Observations were conducted in varied settings, including island-style offices at Itoki Corporation and Osaka Metropolitan University, as well as modern open spaces. Data were analyzed using the KA method to construct a value map. The integrated value map indicates that one group of prioritized values exists along a continuum, shifting from chair-specific attributes, such as stability and physical support during focused work, to broader workspace-related values, including mobility and environmental fit. In contrast, another group of prioritized values is associated with task engagement, ranging from support for deep concentration to features that enable mental refreshment and rest. This research clarifies how experiential values transition from physical chair features to holistic workspace qualities. This research clarifies how experiential values shift from physical chair features to more holistic workspace qualities, as well as how user needs dynamically fluctuate between states of concentration and rest depending on the task context. These qualitative findings offer meaningful guidance for future product development grounded in human-centered design.
Sayaka Noda, Toshihisa Doi, Luo Weiyang, Sayaka Yamane, Seiji Minami, Satsuki Harada
Open Access
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Envisioning Uncertain Futures: A Structured Framework for Speculative Co-design Workshops
While speculative design is increasingly used to envision uncertain futures, there is a lack of facilitation guidance on how to systematically prepare and structure co-design workshops to support participant imagination and the envisioning process. This study addresses this gap by detailing a systematic approach to speculative co-design. This study employed a qualitative, observational case study involving five speculative co-design workshops with 20 participants in the automotive field. Through the application of a six-stage workshop process that utilised embodied and improvisational techniques, we investigated how participants' engagement could be enhanced, and rich qualitative data could be generated. Through inductive observations of the workshops and thematic analysis of the workshop content, we identified three core facilitation components that enable imaginative envisioning of uncertain futures: 1) narrative setting, 2) enactment cue and 3) empowerment dynamics. The findings formalise the components into the Action Wheel as a methodological guide. This research presents a replicable methodological facilitating guide that provides a starting point for researchers and practitioners to enable participants to engage with uncertain futures in speculative design contexts.
Kyungjoo Cha, Ecem Ince
Open Access
Article
Conference Proceedings
Psychological Mechanism and Classification of Similarity Judgment in Design:Expert Interviews and Questionnaire Survey
Similarity judgment is a core cognitive activity in conceptual design, directly affecting design thinking efficiency, outcome novelty, and decision rationality. While its significance in combinatorial design and analogical reasoning is confirmed (McTeague, 2022), the underlying psychological mechanism and systematic classification in design scenarios remain understudied. Integrating cognitive psychology theories, this study adopted expert interviews (n=12) and questionnaire surveys (n=198 valid responses) with professional designers to explore these issues. Results show that design similarity judgment follows a dual-process mechanism: structural alignment processing (M=4.23, SD=0.58) dominates, with limited thematic association processing (M=2.87, SD=0.65) as a supplement (r=0.23, p<0.01). It can be classified into three dimensions with weighted order: functional similarity (M=4.35, SD=0.52) > formal similarity (M=3.78, SD=0.61) > contextual similarity (M=2.96, SD=0.73). Work experience and design field further influence judgment preferences. These findings enrich the dual-process model’s contextual application, provide a unified classification system, and offer implications for cognitive ergonomic optimization of design tools and designer training.
Jinpeng Chen, Yulin Zhao, Yanhao Cai
Open Access
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Conference Proceedings
Integrating Embodied Intelligence: A Three-Scenario Design Proposal for the Smart Vehicle Cabin
The automotive industry is transitioning from "mechanical mobility tools" to the "Third Living Space." As Level 3+ autonomy reduces driving tasks, the cabin becomes a space for social interaction, work, and rest. However, current HMI remains trapped in "Screen-Centrism"—compressing 3D physical interactions into 2D GUIs—causing dual crises: cognitive overload for drivers and emotional alienation for passengers.This study constructs a design framework beyond GUI by introducing "Embodied Intelligence." Using an Explanatory Sequential Mixed-Methods design, we first conducted NLP on 145,820 social media entries to map user expectations, followed by Day Reconstruction Method inquiries with 30 families, revealing deep-seated pain points: "Black Box Anxiety" (rear-seat safety) and "Physical Barriers" to social interaction.Through phenomenological reduction, we propose the "Anchoring-Linking-Transforming" (A-L-T) framework: intelligence must build trust through Anchoring social roles, offload cognition through Linking multimodal environmental cues, and reconstruct social relations through Transforming physical space. As materialization, we present "Embodied-C"—featuring an eHMI System, Spatially Fluid Agent, and Modular Reconfigurable Console. This study offers a model for next-generation human-vehicle symbiosis, shifting from "Command-Control" to "Embodied Co-habitation."
Haoran Yu, Danhua Zhao
Open Access
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Conference Proceedings
Gender Sensitive Ergonomic Evaluation of a Disposable Ureteroscope Handle
Disposable flexible ureteroscopy requires prolonged one handed holding, repeated thumb control, and frequent accessory changes. These demands may disadvantage users with smaller hands. This study developed a Human Factors Evaluation for Ureteroscopy system, named HFE-U, based on a User, Task, Environment, and Product model. The system contains five dimensions: grip comfort, interaction comfort, operational portability and efficiency, postural and whole body load, and perceived safety and innovation acceptance. Forty eight candidate indicators were generated from literature review, product analysis, clinician interviews, and questionnaires. Thirty eight core indicators were retained after item analysis and expert content validation. Guided by this system, a four stage iterative design produced a fully integrated handle prototype. In a simulated static holding experiment with 20 female and 20 male students, the prototype showed higher VAS grip comfort than the conventional handle. Female participants showed a larger descriptive improvement, although the sex by handle type interaction was not significant.
Yuang Li, Xiangcheng Qiu, Houqi Huang, Shi Lei Su, Haining Wang, Jing Ou
Open Access
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Conference Proceedings
Cross-Cultural Impressions and Cue Weighting of Avatars for Emergency Announcements: Evidence from China and Japan
Avatars are increasingly used for serious emergency announcements, but cross-cultural differences in impressions and cue weighting remain unclear. We compared participants from China (n=40) and Japan (n=40) evaluating four emergency-announcement avatars. In Part 1, participants watched avatar-based announcement videos and completed comprehension checks; understanding was generally high, while the Chinese participants scored higher than the Japanese with avatar-dependent differences. In Part 2, participants rated the avatars using static reference images (for identification) and reported the importance of six cues (clothes, gender, voice, style, speed, race). Mixed-design analyses showed that cross-cultural differences were most robust for authority, whereas trustworthiness and affability showed weaker effects. The Chinese participants assigned higher overall cue importance than the Japanese, and authority cue-importance patterns differed by country. A supplementary dlib-based facial landmark profile provided descriptive context for avatar-specific China–Japan gaps. These findings highlight the need for country aware validation in designing serious-communication avatars.
Zhang Liwen, Toshikazu Kato, Toru Nakata, Hidekazu Takahashi
Open Access
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Conference Proceedings
An Examination of Factors Contributing to the Perception of Chairs "Blending into" a Space and Their Respective Contributions
When designing office spaces, selecting chairs that "blend into" the environment is crucial for aesthetic and functional integration. This study conducted two investigations to identify the factors and mechanisms that make chairs feel integrated into a space, aiming to support efficient chair development. In Survey 1, the Evaluation Grid Method was employed with 12 individuals highly interested in spatial design to clarify the underlying evaluation structure. The resulting hierarchical diagram revealed strong direct connections between space integration and factors such as matching materials, color coordination, not "looking out of place," and familiarity with the combination. In Survey 2, a web-based questionnaire was conducted with 100 participants to quantify the contribution of these factors. Data were analyzed using a Linear Mixed-Effects Model. The results showed that "Color Harmony," "Visual Integration (not looking out of place)," and "Plausibility (Familiarity)" had the most significant positive effects on the perception of blending. Currently, design decisions often rely on tacit knowledge, but this study provides objective design guidelines to enable evidence-based product development.
Toshiki Kuroda, Toshihisa Doi, Sayaka Noda, Chika Nakatani, Seiji Minami, Satsuki Harada
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An Empirical Examination of Optimal Stimulation Theory and Prototype Theory for the Perceived Fit of Chairs in Office Spaces
This study investigates the psychological mechanisms underlying the perception that a chair “fits into” an office space, focusing on the applicability of Optimal Stimulation Theory and Prototype Theory in environmental psychology. A web-based questionnaire survey was conducted with 100 office workers, using 12 CG-based office space images generated by Adobe Firefly. Participants evaluated the perceived fit of the chair and their impressions of each space using seven-point Likert and semantic differential scales. Because each participant evaluated multiple images, linear mixed-effects models with crossed random effects for participants and images were employed. The perceived fit of the chair was treated as the dependent variable, and impression variables were included as predictors with both linear and quadratic effects. The results showed limited evidence for inverse U-shaped relationships predicted by Optimal Stimulation Theory. In contrast, typicality of chair and predictability demonstrated positive linear effects on perceived fit. These findings suggest that perceived fit is less influenced by optimal stimulation levels and more strongly governed by cognitive fluency and prototype-based evaluation. This exploratory study provides insights into how furniture–space relationships are perceived and offers implications for office furniture and environmental design.
Toshihisa Doi, Toshiki Kuroda, Sayaka Noda, Chika Nakatani, Seiji Minami, Satsuki Harada
Open Access
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Conference Proceedings
Grey Relational Analysis of Bicycle Saddle Modeling Based on Kansei Engineering
As cycling becomes increasingly popular, user expectations for bicycle saddles have evolved beyond basic functionality to more comprehensive perceptual comfort and aesthetic experience. However, there remains a lack of methodology for systematically translating users' subjective impressions of bicycle saddle form into practical design optimisation directions. This study is based on Kansei engineering theory and grey relational analysis , through sample collection, cluster analysis and expert evaluation, representative bicycle saddle samples and core perceptual vocabulary are selected, and the bicycle saddle form is further decomposed into quantifiable modeling elements. Subsequently, factor analysis is used to establish the relationship between modeling elements and core perceptual vocabulary, followed by grey relational analysis to determine the priority ranking of each modeling element under different perceptual vocabulary. The research findings provide a systematic, quantifiable basis for optimization design of bicycle saddle under different perceptual goals. This not only enhances the efficiency of bicycle saddle design but also ensures design outcomes better match users' diverse perceptual requirements.
Li Meihui, Meiyu Zhou
Open Access
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Conference Proceedings
A Product Redesign Approach Based on Negative Text Mining and Kansei Engineering
As smart products continue to proliferate, the abundance of negative reviews on online platforms has become a critical source for uncovering product experience deficiencies. However, negative texts often contain implicit emotions, intertwined semantics, and mixed attribute expressions, making traditional analytical methods insufficient for transforming them into design-ready structured knowledge.This study proposes a product redesign framework that integrates negative text mining with Kansei engineering, establishing a complete process from negative affect extraction to visual product optimization. First, a semantic association graph is constructed from review corpora, and a Graph Convolutional Network is employed to identify key negative factors influencing user experience. These negative factors are then mapped to Kansei dimensions through Partial Least Squares Regression, further linked to adjustable design elements to form a quantitative translation pathway from user dissatisfaction to design language.Based on the derived target Kansei directions, a generative design module is introduced to perform guided visual refinement. The generation process is driven by the target affective features and explores multiple feasible visual improvement schemes. The resulting images provide intuitive references for designers, enabling negative user experiences to be directly translated into design decisions.Experimental results demonstrate that the proposed framework effectively identifies deep-seated negative experiences, provides interpretable connections between textual emotions and design characteristics, and supports product form optimization through generative artificial intelligence. This method highlights the value of negative reviews in experience-driven design and offers a systematic approach for emotion-informed improvement of smart products.
Yizhen Shi, Meiyu Zhou
Open Access
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Conference Proceedings
Exploring Consumer Taste by Award-Winning Product Designers via the Elite Interview
This study aims to explore the significance of taste in product design. Product design is a service-oriented discipline that encompasses the design and development of products catering to the diverse and evolving needs of users. Industrial designers often navigate the balance between the "form and function" of a product, harmonizing aesthetic appeal with practical utility. A deeper understanding of consumer tastes could enable designers to create products that better align with user preferences. In other words, a well-designed product should successfully satisfy the consumer's taste.Researchers conducted elite interviews with ten award-winning product designers from Taiwan, who have received accolades such as the iF, IDEA, Red Dot, GD, and Taiwan Excellence Awards. Based on their perspectives and insights, valuable ideas and concepts regarding the relationship between consumer taste and product design were identified and summarized. The results of the interview indicate that: 1) the taste is constituted by two parts: invisible internal and visible external. Everyone’s taste is unique, subjective, consistent and categorized; 2) consumers choose products with personal taste features to express self-images, show their socioeconomic status, or achieve social identification and adoration; 3) when it comes to taste, consumers always have consistent demands for product design in similar properties or functions; 4) according to elite designers, developing novel user experiences is essential for advancing the understanding of consumers’ taste demands. Finally, we hope this study serves as an important guide for the product design process and methodology, particularly aiding future researchers conducting related studies.
Iou-ren Lin, Wen C Chang, Chien-Hsiung Chen
Open Access
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Conference Proceedings
Kansei Analysis of Spicy Noodle Packaging for Generative AI-Based Design Education
This study examines the Kansei structure of Korean spicy noodle packaging as perceived by teenage female university students and explores its applicability to generative AI-supported design education. An impression evaluation experiment was conducted with 13 participants using seven commercially available packages found in Japanese supermarkets, and 16 Kansei word pairs were rated on a five-point semantic differential scale. Through principal component analysis and biplot visualization, individual packages were shown to occupy distinct positions within this affective space, corresponding to different design strategies such as emphasizing extreme spiciness, approachability, premium quality, or uniqueness. Furthermore, the visualized Kansei structure functioned as an effective reference framework for beginner designers using generative AI, suggesting its potential as both an analytical and educational tool.
Teru Kawakita
Open Access
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Conference Proceedings
A Kansei Engineering Study on the Effects of Camera Exterior Design Attributes on Nostalgic Perception
Retro-style products have become increasingly prominent in contemporary design practice. This study uses retro-styled cameras as the research object and, from the perspectives of Kansei engineering and product semantics, examines how different appearance factors influence users’ nostalgic perception.The results show that colour has the strongest effect on nostalgic perception, followed by operation-related areas, while non-interactive regions have minimal influence. Leather materials consistently receive higher evaluations than metal, but the effect of material depends on the presence of key design elements. Moreover, the relative influence of design factors remains stable across material conditions. Individual experience and brand-related visual cues further shape nostalgic perception.These findings provide quantitative guidance for the appearance design of nostalgia-inspired products and extend product semantics into the study of emotional perception.
Dingfeng Zhou, Junjie Zhang, Junjie Hong
Open Access
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Conference Proceedings
Effects of Light Color on Visual evaluation of Sorolla’s Outdoor Paintings
The present study investigates the impact of light source characteristics on the subjective perception and aesthetic appreciation of representational paintings, specifically works by Joaquín Sorolla. The primary objective was to determine how correlated color temperature (CCT) and spectral power distribution (SPD) while keeping the CCT constant influence the viewer’s perception of the depicted season, time of day, and overall atmospheric quality. Participants evaluated three artworks—depicting autumn foliage, a winter landscape, and a summer seaside—under 20 illuminant conditions with CCTs ranging from 3000 K to 10,000 K, utilizing both representative daylights and typical light-emitting diode (LED) spectra. The results demonstrate that CCT is the decisive factor in shaping the perceived atmosphere and temporal context while the specific SPD of the illuminant has a negligible effect. The effectiveness of specific lighting was highly dependent on the painting’s content: mid-range CCTs (4000–5000 K) best complemented the vitality of autumn scenes, and a similar range (4000–6500 K) was preferred for the summer seaside scene to capture its natural brilliance. In contrast, high CCTs (8000–10,000 K) were essential for conveying the crisp texture and frigid atmosphere of winter landscapes. These findings suggest that "atmospheric congruency," aligning the CCT of the illuminant with the environmental cues within the artwork, is more critical for viewer appreciation than differences in SPDs. This research provides valuable insights for museum lighting design to optimize the visual experience of representational art.
Shino Okuda, Mana Nishimoto, Satoko Taguchi, Miho Muguruma, Katsunori Okajima, Juan Serra, Daniel Vázquez, Manuel Melgosa
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Ergonomic Design of Childcare-Friendly Play Spaces in Community Parks: A Renovation Approach Based on Childcare Behaviors
Child-friendly cities have gained significant importance in urban design, with childcare behavior playing a key role in both ensuring children's safety and supporting their psychological and social development. Grounded in ergonomics principles, particularly human–environment interaction and behavior-supportive design, this study examines caregiver behaviors in children’s playgrounds within community parks, while considering children’s developmental needs as a contextual factor.Based on behavioral observations and questionnaire surveys, four distinct types of childcare behavior—caring, watching, participating, and following—are identified, and their correlation with children’s developmental stages is established. The findings are further interpreted to reflect caregivers’ needs in terms of visibility, proximity, and engagement. Comparative analyses of exemplary community parks reveal design strategies addressing both macro-level layout and micro-level interventions, such as play equipment and environmental detailing. These strategies are applied to Huilongyuan Park in Beijing, with proposed site-specific improvements including age-differentiated zoning, adjustments to spatial scale, boundary design, and equipment placement. The study aims to enhance the alignment between caregiver behavior and spatial design, creating child-friendly environments that balance safety, accessibility, and opportunities for independent exploration, thereby supporting children’s holistic development.
Xinran Li, Xiaoxi Cheng
Open Access
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Conference Proceedings
Foot Aromatherapy Massager Design
Foot therapy and Aromatherapy have been widely applied in complementary and alternative medicine. Because foot massage work is characterized by prolonged duration, high intensity, and repetitive force exertion, practitioners are prone to occupational injuries caused by excessive hand load, which may further affect treatment quality and their ability to sustain long-term practice. Therefore, this study aims to develop a foot massage tool that integrates foot therapy and Aromatherapy in order to reduce hand burden and enhance massage quality.This study was conducted in three stages: preliminary research, design development, and testing and validation. The preliminary research stage included the investigation of massage techniques and theories, analysis of existing tools, and the establishment of design specifications and objectives. The design development stage involved ergonomic, mechanical, and appearance design. Finally, prototype fabrication, ergonomic testing, and functional testing were carried out to evaluate the feasibility of the product.The product developed in this study has four main features: (1) a rolling mechanism that replaces direct finger pressure, thereby reducing the load on the finger joints; (2) a stainless-steel roller ball design that provides stable and even force application; (3) an integrated essential oil reservoir and automatic oil dispensing mechanism, combining the effects of Aromatherapy and massage; and (4) an ergonomically designed handle that enhances grip comfort, operational stability, and efficiency.
Yuting Hsiao, Dengchuan Cai
Open Access
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Concept design of bathing aids for long-term care institutions
Due to the shortage of care service personnel in Taiwan and persistent time pressure, assisting residents with bathing in long-term care facilities is one of the most physically demanding caregiving tasks. Bathing requires a series of labor-intensive actions, including transferring, repositioning, washing, rinsing, drying, and dressing, which impose substantial physical strain on caregivers.This study first investigated these occupational risks through an empirical assessment involving 15 Taiwanese care service personnel. Using the Rapid Entire Body Assessment (REBA) method and a musculoskeletal discomfort questionnaire, the results clearly classified bathing tasks as high-risk operations. Both posture risk scores and reported pain were most concentrated in the lumbar region, indicating significant lower-back strain and a clear need for intervention.Based on these findings, the study proceeded to develop a specialized bathing assistive device. The product development followed a standard design workflow, beginning with direct observations and needs analysis from frontline caregivers, which were translated into concrete design objectives and technical specifications. The design process integrated functional design, mechanical structure, human factors (ergonomic) considerations, and appearance design. The final product key functions include safe transfer between bed and device, assisted mobility between bedroom and bathroom, usability for both sitting and lying down, hygienic temporary waste management, and simplified operation and maintenance. Overall, the device effectively reduces physical and mental burden on caregivers while improving bathing efficiency and safety.
Hui-wen Hsiao, Dengchuan Cai, Yuting Hsiao
Open Access
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Musculoskeletal pain survey and bathing posture risk assessment for long-term care staff
Long-term care staff often experience heavy workloads and physical and mental fatigue. Among caregiving tasks, bathing is particularly physically demanding, requiring repeated actions such as turning, transferring, washing, rinsing, drying, and dressing or undressing residents. Turning and transferring are especially strenuous. This study investigated musculoskeletal pain among long-term care staff and evaluated the postural risks they face during bathing to inform the design of work procedures and assistive devices in long-term care facilities.The Nordic Musculoskeletal Questionnaire (NMQ) was used to assess musculoskeletal pain in 10 caregivers from three long-term care institutions in Taiwan, while the Rapid Entire Body Assessment (REBA) was applied to evaluate postural risks during bathing. All institutions and participants joined the study voluntarily with prior consent.The results showed that the mean musculoskeletal pain score was 1.58 (SD = 1.43), indicating mild to moderate pain, with an average prevalence of 65%. The most severe pain was reported in the lower back (M = 2.1, SD = 1.64) and left elbow/forearm (M = 2.1, SD = 1.51). Lower back pain was more severe than upper back pain, and right-side pain was generally more severe than left-side pain. The mean REBA score during bathing was 11.4 (SD = 0.92), indicating a high-risk posture that requires immediate intervention and movement modification. The trunk (M = 4.2, SD = 0.6) and upper limbs (M = 3.7, SD = 0.46) showed the highest postural risk. These findings suggest that bathing is a high-risk caregiving task. Long-term care institutions should strengthen staff training and improve assistive device design to reduce the risk of occupational injury.
Dengchuan Cai, Hui-wen Hsiao, Chung-hsien Liu, Yuting Hsiao
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In search of lost design: cross-pollination in designing a musical instrument
The paper investigates divergent thinking as a competence to generate creativity and new ideas by exploring multiple options and connections, contrasting with convergent thinking which focusses to a single solution. In this case, the design of a musical instrument is a chance to understand how things become together, testing and developing an organism, joining the need for semantic and aesthetical qualities with high performance potentials, and linking handmade production with cutting-edge technologies and materials. Creativity and innovation are emphasized with the 2030 Innovation Agenda, which comprises society and culture. Methodologically, the study is exploratory based on qualitative research methods, and it comprises academy and productive sectors. The paper highlights other research pro-jects that demonstrate this team's ability to create connections with design, music, culture, and social issues. The study explores new possibilities for systemic design, activating a network of all entities. It is intended that this research may be instigator for reflection on cross-pollination between design research and society.
Liliana Soares, Ermanno Aparo, Rita Aparo
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Effects of Luminance and Animation Type on Glare and Visibility of Dynamic Signs: An Ergonomic Study Considering Age-Related Differences
Increased luminance enhances sign visibility and readability, but excessive luminance can induce discomfort glare, particularly among older adults. However, few systematic investigations have examined the combined effects of luminance, animation type, and age. This study explores how luminance and animation type (flash vs. slide) affect perceived glare, visibility, and readability in different age groups. Six luminance levels (15.9–1,237 cd/m2) were tested. Based on stimulus size, the glare index at 762 cd/m2 was calculated to be 30.42, categorized as “intolerable.” Dynamic signs were evaluated by 15 participants in their 20s and 15 in their 60s. After 5 minutes of dark adaptation, the participants rated glare, visibility, and readability on seven-point scales and completed a comprehension task. Three-way analysis of variance (Age Group × Animation Type × Luminance) was performed. The results showed that comprehension accuracy exceeded 80% in all conditions, suggesting that animation does not necessarily impair recognition. Perceived glare increased with luminance, with an age-by-luminance interaction indicating that younger adults felt more glare at high luminance than older adults. Notably, older participants rated slide animations as significantly more visible and readable than flash animations. These findings suggest that, for older adults, slide animations at moderate luminance provide an optimal balance between visibility and comfort.
Hiroshi Watanabe, Hiroyasu Ujike
Open Access
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Quantifying Mouse Grip Comfort: A Multi-Level Human Factors Evaluation Framework
As a ubiquitous human-computer interaction tool, the computer mouse requires rigorous ergonomic design to support performance and reduce upper-limb musculoskeletal risk during prolonged use. However, current comfort assessments remain fragmented and seldom translate multidimensional perceptions into empirically weighted design priorities. This study proposes a human factors evaluation framework that combines qualitative indicator elicitation, exploratory factor analysis (EFA), and the analytic hierarchy process (AHP) to quantify mouse grip comfort. An initial pool of more than 70 descriptors was compiled from literature, user interviews, and online reviews, and an importance screening survey (N = 157) reduced these to 12 core descriptors. A second survey (N = 106) provided data suitable for EFA (KMO = 0.69), yielding four latent dimensions (Dynamic Maneuverability, Muscular Load, Static Support, and Tactile Softness) that explained 60.93% of the variance. These dimensions defined the criteria level of a three-level hierarchy (goal, criteria, and indicators), and AHP weights were derived from pairwise comparisons provided by 32 experts. Dynamic maneuverability received the highest criteria weight (0.3933), and lateral grip stability had the largest composite weight among 19 operational indicators (0.1182). A case study with three representative commercial mice further demonstrated the framework’s utility for benchmarking and design prioritization. Dynamic maneuverability was most strongly associated with overall comfort (Spearman’s rho = 0.71) based on Borg CR-10 ratings. The framework provides a structured pathway for comfort-oriented mouse design and supports future integration with objective measures such as EMG, pressure distribution, and movement smoothness.
Jie Gao, Yilin Yang, Ke Zeng, Haining Wang
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Effect of Cornice Lighting Distribution on Perceived Ceiling Height in an Immersive Virtual Environment
Indirect lighting is a crucial element in determining the atmosphere of a space; however, its influence on dimension perception remains insufficiently researched. Therefore, this study investigated the effects of cornice lighting distribution characteristics on perceived ceiling height using virtual reality (VR) presented via a head-mounted display (HMD). In the experiment, perceived ceiling height was measured using the method of adjustment in two environments: a narrow space where side walls were visible, and a wide space where side walls were not visible. The main variables were the distance from the light source to the wall (150 mm vs. 300 mm) and brightness. Results indicated a statistically significant difference in the narrow space, where the perceived ceiling height was greater in the 150 mm condition compared to the 300 mm condition. This suggests that intense illumination on the upper part of the wall may have directed visual attention upward. thereby emphasizing verticality. In contrast, no significant difference was observed in the wide space where side walls were excluded from the field of view. This implies that side walls function as a "reference frame" for grasping spatial proportions. In the absence of this frame, the observer's attention shifted toward the horizontal expanse, attenuating the vertical effects of the lighting. These findings suggest that the impact of cornice lighting distribution on perceived ceiling height depends strongly on spatial composition. In architectural design, controlling light distribution on the upper wall is an effective strategy for enhancing the sense of openness in small-scale spaces; however, its efficacy may be limited in large spaces where overall proportion dominates perception.
Shinnosuke Takano, Yohsuke Yoshioka
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EcoCar: A Human-Centered Design Approach to Sustainable Urban Micro-Mobility
The EcoCar project emerges as a response to the urgent need for decarbonization and for a new paradigm in personalised urban mobility. Rather than extending existing solutions, EcoCar proposes a structural transformation in a sector that has consistently failed to meet environmental targets. The project aims to establish the foundations of a simplified and efficient mobility ecosystem, breaking away from the complexity and material intensity typically associated with conventional electric vehicles. Positioned within the L-category, EcoCar aligns with requirements for low energy consumption, accessibility, and the principles of Sustainable Urban Mobility Plans. Its design challenges the traditional automotive model by retaining only essential elements and prioritising modularity, customisation, additive manufacturing, and circular-economy values such as repair, reuse, and recycling. Compact and intelligent, it draws on lessons from existing micro-vehicles while defining clear objectives for safety and commercial viability. Integrated into a smart-city context, EcoCar supports communication between vehicles and users, facilitating access to traffic, pollution, and charging information, and promoting a connected urban mobility ecosystem. Its reduced dimensions contribute to more efficient traffic flow, with the potential to significantly increase circulation capacity compared to conventional cars. Developed from a blank-slate approach, EcoCar was conceived strictly around real user needs. Human-factors research, anthropometric data, and iterative physical experimentation guided the development of a full-scale prototype, enabling the evaluation of ergonomics, visibility, usability, and interior layout. The construction and public presentation of the prototype validated the concept and established a solid foundation for future development towards a functional electric vehicle.
Paulo Jorge Martins Parra, André Gouveia, João Rocha
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Revealing Hierarchical Evaluation Structures in Office Chair Usage Using the Evaluation Grid Method
Diversification of office workstyles has increased the need to understand how users evaluate office chairs in real work contexts. This study explored users’ hierarchical evaluation structures for five office chairs with different characteristics using the Evaluation Grid Method (EGM). Five office staffs who regularly use office chairs were recruited in this study (mean age = 38.6 years, SD = 8.93). Over five weeks, each participant used one provided chair from Monday to Wednesday and returned to their usual chair on Thursday and Friday; the weekly chair order was randomized. After the usage period, individual EGM interviews were conducted by at least two researchers, who recorded responses and constructed evaluation structure diagrams in real time, then confirmed the completed structure with each participant. Each participant ranked the five chairs and proceeded through stepwise comparisons with laddering to elicit links between concrete attributes and higher-level values. Participant-level maps were integrated by retaining items shared by more than one participant and merging semantically similar items. The integrated map highlighted pathways connecting lightweight/compact attributes with perceived ease of movement and social communication, and pathways linking fit- and posture-related perceptions with reduced fatigue and sustained work and concentration. These findings illustrate how users translate chair attributes into workplace-relevant values and can inform user-centered chair design requirements.
Luo Weiyang, Toshihisa Doi, Sayaka Noda, Sayaka Yamane, Seiji Minami, Satsuki Harada
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Conference Proceedings
Development and Validation of a Dynamic Multi-Modal Digital Human Hand Model for Ergonomic Design of Handheld Products
Handheld interactive products require device geometries that accommodate coupled skeletal motion and nonlinear soft-tissue deformation during grasping and pressing. However, many existing digital hand models prioritize either kinematics or surface geometry and therefore provide limited predictive power for contact mechanics and deformation under realistic interactions. This study developed a Dynamic Digital Human Hand Model (DHHM) that integrates (i) percentile-based hand surface models derived from 3D scans of 864 Chinese adults, (ii) layered internal anatomy (bone, muscle, connective tissue, fat, and skin) refined using anatomical atlases and public anatomical datasets, (iii) inverse-kinematics-driven motion control, and (iv) finite element-based soft-tissue simulation implemented in Ziva VFX using a second-order implicit backward differentiation formula (BDF2) integrator. The P50 model was validated using motion capture, 3D surface scanning, and surface electromyography (sEMG) from four participants whose hand dimensions were close to the P50 hand (maximum absolute deviation 2.0 mm across eight key measures). Participants performed seven representative grasp/press tasks involving a mouse, a laparoscopic ultrasonic scalpel, a surgical needle holder, and a smartphone. Across tasks, the DHHM reproduced primary contact patterns observed in scanned postures. Surface deviation analysis showed high agreement between simulated and scanned skin surfaces within an industrial tolerance (maximum deviation within ±1.655 mm). Predicted activation trends of thenar, hypothenar, and extensor muscle groups were qualitatively consistent with sEMG across task types. The proposed DHHM provides a validated pathway for high-fidelity hand-product interaction simulation to support ergonomic design with reduced reliance on physical prototypes.
Huilin Dai, Yilin Yang, Haining Wang
Open Access
Article
Conference Proceedings
Construction and Validation of a Multi-Level Evaluation System for Mattress Comfort
Robust mattress comfort evaluation is essential for translating human-mattress interaction evidence into actionable product design requirements; however, current studies and standards often use non-aligned indicator sets and frequently treat comfort as a static, single-time-point construct. This study developed and validated a hierarchical, human-centered evaluation system that integrates subjective perceptions with objective interface pressure metrics and explicitly differentiates early- and later-phase comfort perceptions. Based on a systematic literature review and relevant standards (e.g., GB/T 43007-2023; EN 1957), candidate indicators were refined through expert ratings (n = 5) and redundancy screening, yielding a four-level framework (goal–dimension–primary–secondary) comprising three dimensions, six primary indicators, and ten secondary indicators. A controlled within-subject experiment was then conducted with 28 adults (19 normal-weight; 9 overweight/obese; 14 males and 14 females; 21–36 years) who evaluated soft, medium, and firm mattresses using a 5-point Likert scale (−2 to +2) while supine interface pressure was recorded at 5 min (early phase) and 30 min (later phase). The questionnaire showed good internal consistency (Cronbach’s α = 0.82) and content validity (CVI = 0.86). Across both body types, medium firmness yielded the highest mean ratings for later-phase overall comfort and fatigue relief. Whole-body pressure metrics showed limited associations with overall comfort, whereas regional pressure parameters, particularly in the shoulder and waist, exhibited clearer and body-type-dependent relationships with comfort-related ratings. The proposed system provides a structured basis for standardized comfort assessment and supports region-specific (zonal) mattress optimization.
Shu Wang, Yuxuan Liu, Yujia Du, Yan Li, Guo Li, Huafeng Shan, Chun Wang, Haining Wang
Open Access
Article
Conference Proceedings
No-Trace Seating: A Probabilistic Design Approach to Reducing Visible Moisture Marks Through Passive Geometry
Prolonged sitting often leads to moisture accumulation at the seat–skin interface, resulting in visible moisture marks on seating surfaces after an individual stands. While thermal comfort and perceived sweating during sitting have been widely studied, the formation of visible surface marks and their relationship to human–seat interaction remain largely unexplored in ergonomics and human factors research. Such marks may negatively affect perceived comfort, social confidence, and seating usability, highlighting the need for predictive and design-oriented solutions. This study introduces No-Trace Seating, a predictive modeling and ergonomic design framework aimed at estimating and reducing the likelihood of moisture mark formation during seated activities. The framework integrates human thermoregulation, textile microclimate behavior, contact-interface mechanics, and heat–mass transfer to identify key contributors to moisture accumulation at the seat–skin interface. Primary predictors include sitting duration, body mass index (BMI), contact-pressure distribution, seat and clothing vapor resistance, interface temperature gradients, and ambient humidity. These parameters are incorporated into a hybrid predictive approach combining a simplified physical moisture-balance model with a statistical classification method to estimate the probability of visible mark formation. The model enables both analytical understanding and practical assessment of seating conditions associated with increased moisture risk. To translate prediction into a design intervention, a ventilated seating concept is proposed. The design employs micro-airflow channels and high moisture-vapor-transmission-rate (MVTR) materials to enhance airflow and moisture dissipation at critical contact regions. Preliminary simulations indicate improved microclimate regulation and reduced predicted moisture accumulation compared to conventional seating materials.
Anjali Chauhan
Open Access
Article
Conference Proceedings
Bridging the Proprioceptive Gap: Ergonomic Development and Evaluation of a Task-Specific Controller for Adolescent First-Aid Serious Games
Although digital twins provide high visual immersion in medical education, existing emergency training paradigms suffer from a significant mismatch between sensory input and motor output. First-aid skills rely heavily on proprioception and physical resistance, yet current digital interactions reduce complex biomechanical tasks to symbolic commands, creating a proprioceptive gap and risks of negative muscle memory transfer. This study proposes a human-factors-driven framework to map user perceptions to physical engineering parameters. A survey of 320 adolescents identified perceived control and visual aesthetics as core drivers of embodied cognition. Ergonomic benchmarking established a 12 percent scaling factor based on hand data differences between adolescents and adults. Morphological evolution using industrial clay determined an optimal 22.5 degree tilt angle for the operation panel to ensure an anatomical neutral position. A high-fidelity prototype was developed featuring anthropometric alignment, a modular magnetic system, and nonlinear variable stiffness feedback that simulates realistic resistance from soft tissue to bone. A within-subject experiment with 20 adolescents showed that the specialized device significantly outperformed general-purpose tools with p < 0.001. The mean System Usability Scale score increased from 61.75 to 85.25, while the Borg RPE fatigue rating decreased from 15.35 to 10.75. These results confirm that the design significantly enhances embodied cognition. This research provides an innovative tool for first-aid training and establishes a quantifiable paradigm for developing specialized interaction equipment for safety-critical tasks.
Luyu Song, Yiwei Zhao, Tianmei Zhang
Open Access
Article
Conference Proceedings
A Deviation Propagation Graph Model and Deviation Propagation Computation Method for Rigid–Flexible Hybrid Assembly
In box-type spacecraft structures, machine tools, and similar complex products, assembly variation transfer is governed jointly by multilevel assembly hierarchy, parallel support chains, and the elastic response of compliant parts. Under such conditions, classical formulations based on a single tolerance chain or rigid-body accumulation cannot preserve assembly topology, part-level tolerance relations, and compliant coupling within a unified representation. This paper presents a graph-based method for rigid-flexible hybrid assembly variation analysis. An assembly directed graph (ADG) is used at the assembly level to encode assembly sequence, locating datums, and interface dependency, while a dimension and tolerance propagation graph (DTPG) is used at the part level to organize feature-level relations among dimensions, geometric tolerances, and measured deviations. A propagation-path subgraph is then extracted on the ADG for a designated source datum and target functional feature, and coupled with the relevant DTPGs to generate an assembly relation propagation graph based on functional element pairs (FEPs). In this way, all effective parallel transmission branches are preserved explicitly and remain available for branch-wise comparison and variation tracing. A plate-type rigid-flexible hybrid assembly case demonstrates that the proposed method preserves the effective transfer structure associated with the target feature and provides a clear basis for dominant-branch identification and assembly process adjustment.
Yikai Zhou, Feng Lv, Zuguang Huang, Haoyu Yu, Xiaojun Liu
Open Access
Article
Conference Proceedings
Thermal Illusion for Wearables: Effects of Vibrotactile Parameters and Placement on Thermal Masking and Comfort
Within the increasing capability of computing and battery of handheld and wearable electronics, device heating has become a critical issue of user comfort and hardware usability. From Gate Control Theory, haptic stimulation may mitigate the thermal discomfort. Through two within-subjects experiments, we examined whether vibrotactile stimulation can attenuate contact-heat unpleasantness and whether placement on the upper limb provides the most actionable design guidance. Experiment 1 screened vibrotactile parameters using 7-point ratings and found an efficacy-tolerability trade-off: amplitude and duty cycle dominated perceived outcomes, whereas frequency had comparatively small effects. We therefore fixed frequency at 150 Hz and selected three candidate codes (221/231/232) spanning strong-effect to balanced profiles. Experiment 2 evaluated these candidates during individualized ramped heating (baseline vs. vibration) using window-locked metrics within 35–48 °C. Vibration generally reduced unpleasantness relative to baseline. Placement effects were most reliable in the mid-to-high window (L2; Friedman χ2 = 7.87, p = 0.0195), driven by robust forearm attenuation (Wilcoxon p = 0.0054, dz ≈ −0.73). Vib-code differences were not stable at the group level, although some codes showed within-window reductions. Late-window results were treated as exploratory due to sparse sampling under conservative stop criteria.
Jiaqi Zheng, Wei Wang, Guanhua Sun, Ruixiao Zheng
Open Access
Article
Conference Proceedings
Design of Handheld Fire Extinguishers Based on Human-Centered Design Principles
The high incidence of fire accidents poses a serious threat to life and property safety. The practical performance of handheld fire extinguishers directly determines the effectiveness of fire rescue. Currently, commercially available handheld fire extinguishers commonly suffer from issues such as complex operational procedures, excessive overall weight, and a limited scope of suitable user groups. It is challenging to master their operation methods. This study aims to provide new insights for the innovative design of handheld fire extinguishers based on human-centered design principles, fully considering the diverse needs of users, thereby enhancing their operational efficiency. To achieve these objectives, this study employed methods including literature review, expert interviews, and questionnaire surveys to analysis user behavior and needs. By synthesizing the above research, an innovative design framework for handheld fire extinguishers was proposed. Based on this framework, a handheld fire extinguisher design scheme that aligns with users' actual needs was proposed. This study provides theoretical and practical references for product innovation design research of handheld fire extinguishers.
Meng Fan Li, Lei Zhong
Open Access
Article
Conference Proceedings
Material Immortality: Designing for Eternity
In this article, we aim to highlight a complementary analysis within the universe of environmental design projects, taking as a starting point a design methodology based on the concept of reuse. Daily involvement with the field of design compels us to reflect on the issue of the new. Not only for iconic preservation, but also for the creative stimulus that reuse represents as an emerging concept in an exhausted consumer society. The reuse of an existing building, product, or raw material not only promotes a cultural connection of memory, but also a sustainable action. The designer must consider how it is designed and its relationship to the function it will perform. In short, with this research, we intend to highlight the need for a design approach that extends the useful life of spaces.
Catarina Carreto, Rui Carreto
Open Access
Article
Conference Proceedings