我們提出了Portal，一種可進行互動的異空間窗口；學生可透過Portal聚焦講師正在講解的部分，並將手穿過Portal、在講師的視野中指出問題，讓講師即時了解問題所在；講師透過Portal可以即時了解學生產生問題的時間點、了解學生正在學習和產生疑惑的地方。因此，講師可以得知學生的學習狀況、精確了解學生的問題，並根據狀況和學生的知識水準給予即時的協助。Portal提供正在虛擬世界中進行教學的使用者擁有更豐富的互動機會，讓講師和學生擁有更佳的教學經驗及學習效果。

本文將詳細介紹Portal的概念、設計、實踐與應用，以及初步的使用者評估結果，進一步了解Portal的使用者體驗與實用性。

We present Portal, a virtual window for a user to interact with another user in the virtual world. In this work, we explored instructors and novices remote teaching in Virtual Reality(VR). The novice can focus the part of the instructor is teaching currently, point out the problem in real-time by passing a hand through the Portal. The instructor can grasp the novice's state, comprehend novice's problems accurately immediately, and give the novice appropriate solutions and answers according to the novice's baseline knowledge.

Herein, the design and implementation of Portal are described in detail along with demonstrations of its applications and the results of a preliminary user evaluation conducted to understand the users' experience with Portal.

[1] Active reading experience questionnaire: Development and validation of an instrument for studying active reading activities. Volume 26, Waynesville, NC.
[2] The effect of question preview in listening comprehension tests. Vol 14, Issue 2, Rome.
[3] Google hangout: https://hangouts.google.com/?hl=zh-TW.
[4] Photon unity network. https://www.photonengine.com/en-US/photon.
[5] Respiratory tutorial no.1. https://www.youtube.com/watch?v=Noho9WYR8Kkt=1s.
[6] Respiratory tutorial no.2. https://www.youtube.com/watch?v=uj5qYUqjaSs.
[7] Toybox demo for oculus touch: https://www.youtube.com/watch?v=iFEMiyGMa58.
[8] Zoom: https://zoom.us/meetings.
[9] Isaacs Ellen A and Clark Herbert H. References in conversation between experts and novices. In Journal of Experimental Psychology: General 116(1), Journal of Experimental Psychology: General 116(1), pages 26–37, New York, NY, United States, 1989.
[10] Yuan-Chia Chang, Hao-Chuan Wang, Hungkuo Chu, Shungying Lin, and Shuoping
Wang. Alpharead: Support unambiguous referencing in remote collaboration with
readable object annotation. In CSCW ’17: Proceedings of the 2017 ACM Conference
on Computer Supported Cooperative Work and Social Computing, CSCW’17, pages
2246–2259, New York, NY, United States, 2017. ACM.
[11] Sarah D’Angelo and Andrew Begel. Improving communication between pair pro-
grammers using shared gaze awareness. In CHI’17: Proceedings of the 2017 CHI
Conference on Human Factors in Computing Systems, CHI’17, New York, NY, United States, 2017. ACM.
[12] Sarah D’Angelo and Darren Gergle. Gazed and confused: Understanding and de-
signing shared gaze for remote collaboration. In CHI ’16: Proceedings of the 2016CHI Conference on Human Factors in Computing Systems, CHI ’16, pages 2492–
2496, New York, NY, United States, 2016. ACM.
[13] Paul Dourish and Victoria Bellotti. Awareness and coordination in shared
workspaces. In CSCW’92: Proceedings of the 1992 ACM conference on Computer-
supported cooperative work, CSCW ’92, pages 107–114, New York, NY, United
States, 1992. ACM.
[14] Ruofei Du, David Li, and Amitabh Varshney. Geollery: A Mixed Reality social
Media Platform. In Proceedings of the 2019 CHI Conference on Human Factors in
Computing Systems, CHI ’19, pages 1–13, Glasgow, Scotl, UK, 2019. ACM.
[15] Susan R. Fussell, Robert E. Kraut, and Jone M Siegel. Coordination of communication: effects of shared visual context on collaborative work. In CSCW ’00: Proceedings of the 2000 ACM conference on Computer supported cooperative work, CSCW’00, pages 21–30, New York, NY, United States, 2000. ACM.
[16] Ge Gao, Sun-Young Hwang, Garbriel Culbertson, Susan R. Fussell, and Malte F.
Jung. Beyond information content: The effects of culture on affective grounding in instant messaging conversations. In Proceedings of the ACM on Human-Computer
Interaction, Volume 1, Issue CSCW, New York, NY, United States, 2017. ACM.
[17] Darren Gergie, Robert E. Kraut, and Susan R. Fussell. Using visual information for grounding and awareness in collaborative tasks. In Human-Computer Interaction, Volume 28, pages 1–39, New York, NY, United States, 2013. ACM.
[18] Darren Gergle, Robert E. Kraut, and Susan R. Fussell. Using visual information for grounding and awareness in collaborative tasks. In Human-Computer Interaction 31:1, Volume 28, New York, NY, United States, 2013. Taylor Francis Group.
[19] Chris Greenhalgh and Steven Benford. Massive : A virtual reality system for teleconferencing. In Computer Human Interfaces (TOCHI), Volume 2, Issue 2, pages
239–261, New York, NY, United States, 1995.
[20] A. Guye-Vuilleme, T. K. Capin, I. S. Pandzic, N. Magnenat Thalmann, and D. Thalmann. Nonverbal communication interface for collaborative virtual environments. In Virtual Reality, 4(1), pages 49–59, SAN FRANCISCO, CA, USA, 1999.
[21] Sebastian Herscher, Connor DeFanti, Nicholas Gregory Vitovitch, Corinne Brenner, Haijun Xia, Kris Layng, and Ken H Perlin. Cavrn: An exploration and evaluation of a collective audience virtual reality nexus experience. In UIST’19: Proceedings of the 32nd Annual ACM Symposium on User Interface Software and Technology, UIST ’19, pages 1137–1150, New York, NY, United States, 2019.
[22] Pamela J. Hinds. The curse of expertise: The effects of expertise and debiasing methods on prediction of novice performance. In Journal of Experimental Psychology: Applied 5(2), Journal of Experimental Psychology: Applied 5(2), pages
205–221, California, 1999.
[23] Pamela J. Hinds. The curse of expertise: The effects of expertise and debiasing methods on prediction of novice performance. In Journal of Experimental Psychology: Applied, 5(2), Washington, America, 1999. American Psychological Association.
[24] Donald B. Bailey Jr. and Sharon A. Palsha. Qualities of the stages of concern questionnaire and implications for educational innovations. In The Journal of Educational Research, Volume 85, Issue 4, New York, NY, United States, 2010. Taylor and Francis Group.
[25] Malte F. Jung. Affective grounding in human-robot interaction. In HRI’17: Proceedings of the 2017 ACM/IEEE International Conference on Human-Robot Interaction, New York, NY, United States, 2017. ACM.
[26] Pekka Kallioniemi, Sumita Sharma, and Markku Turunen. Citycompass: A collaborative online language learning application. In CSCW ’16 Companion: Proceedings of the 19th ACM Conference on Computer Supported Cooperative Work and Social Computing Companion, CSCW ’16, pages 94–97, SAN FRANCISCO, CA, USA,
2016.
[27] Christos Katsanos, Nikolaos Tselios, and Michalis Xenos. Perceived usability evaluation of learning management systems: A first step towards standardization of the system usability scale in greek. In 2012 16th Panhellenic Conference on Informatics, IEEE’12, Piraeus, Greece, 2012. IEEE.
[28] Juho Kim. Toolscape: enhancing the learning experience of how-to videos. In CHIEA ’13: CHI ’13 Extended Abstracts on Human Factors in Computing Systems,
CHI’13, pages 2707–2712, New York, NY, United States, 2013. ACM.
[29] Michail D. Kozlov and Cornelia S. GroԤe. Online collaborative learning in dyads: Effects of knowledge distribution and awareness. In Computers in Human Behavior, Computers in Human Behavior, Bremen, Germany, 2016.
[30] Balasaravanan Thoravi Kumaravel, Cuong Nguen, Stephen DiVerdi, and Bjorn Hartmann. Tutorivr: A video-based tutorial system for design applications in virtual reality. In Proceedings of the 2019 CHI Conference on Human Factors in Computing Systems, CHI ’19, pages 1–12, Glasgow, Scotland UK, 2019.
[31] Andre Kunert, Alexander Kulik, Stephan David Beck, and Bernd Froehlich. Photoportals: Shared references in space and time. In CSCW’14: Proceedings of the
17th ACM conference on Computer supported cooperative work social computing,
CSCW’14, pages 1388–1399, New York, NY, United States, 2014. ACM.
[32] Rodger Lea, Yasuaki Honda, and Kouichi Matsuda. Virtual society: collaboration in 3d spaces on the internet. In Groupware and the World Wide Web, 6, pages 227–250, 1997. Springer, Dordrecht.
[33] Schommer M. Effects of beliefs about the nature of knowledge on comprehension. In Journal of Educational Psychology, 82(3), Washington, DC, 1990. American Psychological Association.
[34] Liang Men and Nick Bryan-Kinns. Lemo: Exploring virtual space for collaborative creativity. In CC ’19: Proceedings of the 2019 on Creativity and Cognition, CC’19, pages 71–82, San Diego, CA, USA, 2019. ACM.
[35] Johanna Doris Moore. Responding to: 20huh?":answering vaguely articulated
follow-up questions. In ACM SIGCHI Bulletin, Volume 20, Issue SI, New York,
NY, United States, 1989.
[36] Barbara A Munjas and PhD. FAAN. From novice to expert: Excellence and power
in clinical nursing practice. In Journal of Psychosocial Nursing and Mental Health Services, 23(5):39, pages 1–309, New York, NY, United States, 1985. Patricia Benner Menlo Park, California: Addison Wesley.
[37] Luciana Nedel, Vinicius Costa de Souza, Aline Menin, Lucia Sebben, Jackson Oliverira, Frederico Faria, and Andersom Maciel. Using immersive virtual reality to reduce work accidents in developing countries. In IEEE Computer Graphics and
Applications, Volume: 36, Issue 2, pages 36–46, 2016. Springer, Dordrecht.
[38] Ikujiro Nonaka. A dynamic theory of organizational knowledge creation. In Organization Science, Volume 5, New York, NY, United States, 1994. ACM.
[39] Mai Otsuki, Taiki Kawano, Keita Maruyama, Hideaki Kuzuoka, and Yusuke Suzuki. Thirdeye: Simple add-on display to represent remote participant’s gaze direction in video communication. In CHI ’17: Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems, CHI ’17, pages 5307–5312, New York, NY, United States, 2017. ACM.
[40] Marcio Sarroglia Pinho, Doug A. Bowman, and Carla Maria D S Freitas. Cooperative object manipulation in immersive virtual environments: framework and techniques. In VRST ’02: Proceedings of the ACM symposium on Virtual reality software and technology, VRST’02, New York, NY, United States, 2002. Association
for Computing Machinery.
[41] Martha Ezlizabeth Pollack. Information sought and information provided: an empirical study of user/expert dialogues. In CHI’85: Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, CHI ’85, pages 155–159, New
York, NY, United States, 1985.
[42] Danny M. Kaufman Wilmot Li Rahul Arora, Rubaiat Habib Kazi and Karen Singh.
MagicalHands: Mid-Air Gestures for Animating in VR. In Proceedings of the 32nd
Annual ACM Symposium on User Interface Software and Technology, UIST ’19,
pages 463–477, New York, NY, USA, 2019. ACM.
[43] Frecon E. Stenius and Marten Stenius. Dive: A scaleable network architecture for distributed virtual environments. In Distributed Systems Engineering, Volume 5, Number 3, pages 91–100, Bristol, England, United Kingdom, 1998.
[44] Cristen Torrey, Elizabeth F. Churchill, and David W. McDonald. Learning how: the search for craft knowledge on the internet. In CHI’09: Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, CHI’09, pages 1371–1380,
New York, NY, United States, 2009. ACM.
[45] H. Tramberend. Avocado: A distributed virtual reality framework. In Proceedings IEEE Virtual Reality, Cat. No. 99CB36316, Houston, TX, USA, USA, 2002.
[46] Minh Hong Tran, Gitesh K. Raikundalia, and Yun Yang. Using an experimental
study to develop group awareness support for real-time distributed collaborative
writing. In Information and Software Technology, Colume 48, Issue 11, pages 1006–
1024, Australia, 2006. Elsevier.
[47] K. Watsen. Bamboo-a portable system for dynamically extensible, real-time, networked, virtual environments. In Proceedings IEEE 1998 Virtual Reality Annual
International Symposium, Cat. No.98CB36180, Atlanta, GA, USA, USA, 1998.
[48] Miriam Weinel, Maria Bannert Jorg Zumbach, H. Ulrich Hoppe, and Nils Malzahn. A closer look on social presence as a causing factor in computer-mediated collaboration. In Computers in Human Behavior, Volume 27, Issue 1, pages 513–521, Germany, 2011. Elsevier.
[49] Jason W. Woodworth, David Broussard, and Christoph W. Borst. Collaborative
interaction in large explorative environments. In Symposium on Spatial User Interaction, SUI ’19, pages 1–2, New Orleans, LA, USA, 2019. ACM.
[50] Jason W. Woodworth, David Broussard, and Christoph W. Borst. Collaborative
interaction in large explorative environments. In SUI ’19: Symposium on Spatial
User Interaction, SUI’19, New York, NY, United States, 2019.
[51] Haijun Xia, Sebastian Herscher, Ken Perlin, and Daniel Wigdor. Spacetime: Enabling fluid individual and collaborative editing in virtual reality. In Proceedings of the 31st Annual ACM Symposium on User Interface Software and Technology, UIST ’18, pages 853–866, Berlin, Germany, 2019.
[52] Naomo Yamashita, Katsuhilo Kaji, Hideaki Kuzuoka, and Keiji Hirata. Improving visibility of remote gestures in distributed tabletop collaboration. In CSCW ’11: Proceedings of the ACM 2011 conference on Computer supported cooperative work, CSCW ’11, pages 95–104, New York, NY, United States, 2011. ACM.
[53] Chi-Lan Yang, Chien-Wen Yuan, Tzu-Yang Wang, and Hao-Chuan Wang. Know-
ing that you know what I know helps?: Understanding the effects of knowledge
transparency in online knowledge transfer. In Proceedings of the ACM on Human-
Computer Interaction, Volume 2, Issue CSCW, New York, NY, United States, 2018.
[54] Samaneh Zamanifard and Guo Freeman. "the togetherness that we crave": Experiencing social vr in long distance relationships. In CSCW ’19: Conference Companion Publication of the 2019 on Computer Supported Cooperative Work and Social Computing, CSCW ’19, pages 438–442, New York, NY, United States, 2019. ACM.
[55] Yuhang Zhao, Edward Cutrell, Christian Holz, Meredith Ringel Morris, Eyla Ofek, and Andrew D. Wilson. Cooperative object manipulation in immersive virtual environments: Framework and techniques. In Proceedings of the ACM symposium
on Virtual reality software and technology, VRST ’02, pages 171–178, Hong Kong,
2002.