Design Case Studies -- Graphic Representations of Spoken Interactions from Journalistic Data: Persuasion and Negotiations -- A Study on Universal Design of Musical Performance System -- Developing a Knowledge-based System for Lean Communications between Designers and Clients -- Learn & Share to Control Your Household Pests: Designing a Communication Based App to Bridge the Gap between Local Guides & The New Users Looking for a Reliable & Affordable Pest Control Solutions -- Developing User Interface Design Strategy to Improve Media Credibility of Mobile Portal News -- Elderly-Centered Design: A New Numeric Typeface for Increased Legibility -- Research on Interactive Experience Design of Peripheral Visual Interface of Autonomous Vehicle -- Human-Centered Design Reflections on Providing Feedback to Primary Care Physicians -- Interaction with Objects and Humans based on Visualized Flow using a Background-oriented Schlieren Method -- Research on Aging Design of News APP Interface Layout Basedon Perceptual Features -- Research on Modular Design of Children's Furniture based on Scene Theory -- A Design Method of Children Playground Based on Bionic Algorithm -- Bias in, Bias out - The Similarity-Attraction Effect between Chatbot Designers and Users -- Research on Immersive Virtual Reality Display Design Mode of Cantonese Porcelain based on Embodied Interaction -- Design and Research of Children's Robot Based on Kansei Engineering -- User Experience and Technology Acceptance Studies -- Exploring Citizens' Attitudes towards Voice-Based Government Services in Switzerland -- Too Hot to Enter: Investigating Users' Attitudes toward Thermoscanners in COVID times -- Teens' Conceptual Understanding of Web Search Engines: The Case of Google Search Engine Result Pages (SERPs) -- What Futuristic Technology Means for First Responders: Voices from the Field -- Blinking LEDs: Usability and User Experience of Domestic Modem Routers Indicator Lights -- The Smaller the Better? A Study on Acceptance of 3D Display of Exhibits of Museum's Mobile Media -- Research on Information Visualization Design for Public Health Security Emergencies -- Comparative Study of the Interaction of Digital Natives with Mainstream Web Mapping Services -- Success is not Final; Failure is not Fatal - Task Success and User Experience in Interactions with Alexa, Google Assistant and Siri -- Research on the Usability Design of HUD Interactive Interface -- Current Problems, Future Needs: Voices of First Responders about Communication Technology -- Exploring the Antecedents of Verificator Adoption -- Are Professional Kitchens Ready for Dummies? A Comparative Usability Evaluation between Expert and non-Expert Users -- Verification of the Appropriate Number of Communications between Drivers of Bicycles and Vehicles -- User Assessment of Webpage Usefulness -- How Workarounds Occur in Relation to Automatic Speech Recognition at Danish Hospitals -- Secondary Task Behavioral Analysis Based on Depth Image During Driving -- Research on the Relationship between the Partition Position of the Central Control Display Interface and the Interaction Efficiency -- HCI, Social Distancing, Information, Communication and Work -- Attention-based Design and Selective Exposure Amid COVID-19 Misinformation Sharing -- Digital Communication to Compensate for Social Distancing? - Results of a Survey on the Local Communication App DorfFunk -- An Evaluation of Remote Workers' Preferences for the Design of a Mobile App on Workspace Search -- Feasibility of Estimating Concentration Level for Not Disturbing Remote Office Workers Based on Kana-Kanji Conversion Confirmation Time -- A Smart City Stakeholder Online Meeting Interface -- Fostering Empathy and Privacy: The Effect of Using Expressive Avatars for Remote Communication -- PerformEyebrow: Design and Implementation of an Artificial Eyebrow Device Enabling Augmented Facial Expression -- Improving Satisfaction in Group Dialogue: A Comparative Study of Face-to-Face and Online Meetings -- EmojiCam: Emoji-Assisted Video Communication System Leveraging Facial Expressions -- Pokerepo Join: Construction of a Virtual Companion Experience System -- Visual Information in Computer-Mediated Interaction Matters: Investigating the Association Between the Availability of Gesture and Turn Transition Timing in Conversation.

The three-volume set LNCS 12762, 12763, and 12764 constitutes the refereed proceedings of the Human Computer Interaction thematic area of the 23rd International Conference on Human-Computer Interaction, HCII 2021, which took place virtually in July 2021. The total of 1276 papers and 241 posters included in the 39 HCII 2021 proceedings volumes was carefully reviewed and selected from 5222 submissions. The 139 papers included in this HCI 2021 proceedings were organized in topical sections as follows: Part I, Theory, Methods and Tools: HCI theory, education and practice; UX evaluation methods, techniques and tools; emotional and persuasive design; and emotions and cognition in HCI Part II, Interaction Techniques and Novel Applications: Novel interaction techniques; human-robot interaction; digital wellbeing; and HCI in surgery Part III, Design and User Experience Case Studies: Design case studies; user experience and technology acceptance studies; and HCI, social distancing, information, communication and work.