Received November 24, 2021, accepted December 23, 2021, date of publication January 4, 2022, date of current version January 13, 2022.
Digital Object Identifier 10.1109/ACCESS.2021.3140175
A Metaverse: Taxonomy, Components,
Applications, and Open Challenges
SANG-MIN PARK
1
AND YOUNG-GAB KIM
2
, (Member, IEEE)
1
Department of Computer Science and Engineering, Korea University, Seoul 02841, South Korea
2
Department of Computer and Information Security, and Convergence Engineering for Intelligent Drone, Sejong University, Seoul 05006, South Korea
Corresponding author: Young-Gab Kim (alwaysgabi@sejong.ac.kr)
This work was supported by the National Research Foundation of Korea (NRF) funded by the Korean Government (MSIT) under
Grant 2021R1A2C2012635.
ABSTRACT Unlike previous studies on the Metaverse based on Second Life, the current Metaverse
is based on the social value of Generation Z that online and offline selves are not different. With the
technological development of deep learning-based high-precision recognition models and natural generation
models, Metaverse is being strengthened with various factors, from mobile-based always-on access to
connectivity with reality using virtual currency. The integration of enhanced social activities and neural-
net methods requires a new definition of Metaverse suitable for the present, different from the previous
Metaverse. This paper divides the concepts and essential techniques necessary for realizing the Metaverse
into three components (i.e., hardware, software, and contents) and three approaches (i.e., user interaction,
implementation, and application) rather than marketing or hardware approach to conduct a comprehensive
analysis. Furthermore, we describe essential methods based on three components and techniques to
Metaverse’s representative Ready Player One, Roblox, and Facebook research in the domain of films, games,
and studies. Finally, we summarize the limitations and directions for implementing the immersive Metaverse
as social influences, constraints, and open challenges.
INDEX TERMS Artificial intelligence, metaverse, cyber world, avatar, extended reality.
I. INTRODUCTION
Metaverse is expanding rapidly, as seen in Geppetto serving
200 million subscribers and Animal Crossing running an
election campaign in a virtual space. In particular, Roblox’s
monthly active users (MAU) is 150 million, which is used
by 2/3 of children aged 9-12 in the US, and 1/3 of them are
under 16 [1]–[3]. Early studies for the Metaverse focus on
Second Life in 2006 [4]–[6]. However, the current Metaverse
is based on the social values of Generation Z that online ego
is no different from offline ones [7]. Therefore, since the
proportion of social activities and contents grows, it differs
from the previous Metaverse, and a new definition is needed
for the present.
The novel Metaverse differs from the earlier Metaverse
in three ways. First, the rapid development of deep
learning dramatically improves the accuracy of vision and
language recognition, and the development of generative
The associate editor coordinating the review of this manuscript and
approving it for publication was Sudhakar Babu Thanikanti .
models enables a more immersive environment and natural
movement. The processing time and complexity were
reduced using multimodal models as E2E (end-to-end)
solutions with a multimodal pre-trained model. Second,
Metaverse previously served based on PC access and had low
consistency due to time and space constraints, but now it is
possible to easily access the Metaverse anytime, anywhere
due to the mobile devices that can connect to the Internet
at all times. There are 50 million games in Roblox and
the accumulated monthly usage time is 3 billion hours.
People consums more time than social network services
(e.g., TikTok, YouTube). It has a virtuous cycle ecosystem
in which the inflow and income of producers increase as
users and usage time increase while serving various contents,
and thus sales of digital advertisements increase. Lastly, the
current Metaverse differs from the previous one because the
program coding can be done in the Metaverse world, and it
is more bonded to real life with virtual currency. Metaverse
expands with various social meanings (e.g., fashion, event,
game, education, and office) based on immersive interaction.
VOLUME 10, 2022
This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/
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