• (The)Korea Educational Review
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• v.23 no.1
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• pp.35-56
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• 2017

This study is to examine the effects of gesture based interface and display methods to make an effective virtual learning environment. The gesture based interface can provide interactive interface to make objects in the virtual learning environment by generating natural movement of users' gesture. This natural functionality leads users to apply natural movements as they do in real actions. Because of the natural user interface, the gesture based interface is expected to maximize learning outcomes. This study examined how the gesture based interface can be used when a head mounted display is applied for a virtual reality learning environment. For this study 44 colleagues students were participated. Two display methods (head mounted display vs. monitor) and two interface (gesture based interface vs. joystick) were tested to identify which might be more effective. The study was applied to different learning tasks which require different levels of spatial perception. The dependent variables are three constructs of virtual presence (spatial perception, immersiveness, and realness) and task completion time and recall tests. This study discussed potential disadvantages of gesture based interface while it showed positive usages of gesture based interface.

• The Journal of Korean Institute of Next Generation Computing
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• v.14 no.6
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• pp.57-65
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• 2018

Conventional RF signal-based indoor localization techniques such as BLE or Wi-Fi based fingerprinting method show considerable localization errors even in small-scale indoor environments due to unstable received signal strength(RSS) of RF signals. Therefore, it is difficult to apply the existing RF-based fingerprinting techniques to large-scale indoor environments such as airports and department stores. In this paper, instead of RF signal we use the geomagnetic sensor signal for indoor localization, whose signal strength is more stable than RF RSS. Although similar geomagnetic field values exist in indoor space, an object movement would experience a unique sequence of the geomagnetic field signals as the movement continues. We use a deep neural network model called the recurrent neural network (RNN), which is effective in recognizing time-varying sequences of sensor data, to track the user's location and movement path. To evaluate the performance of the proposed geomagnetic field based indoor positioning system (IPS), we constructed a magnetic field map for a campus testbed of about $94m{\times}26$ dimension and trained RNN using various potential movement paths and their location data extracted from the magnetic field map. By adjusting various hyperparameters, we could achieve an average localization error of 1.20 meters in the testbed.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.967-975
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• 2022

Kombucha mutualistic community (KMC) is composed by acetic acid bacteria and yeasts, producing fermented tea with health benefits. As part of the BIOlogy and Mars EXperiment (BIOMEX) project, the effect of Mars-like conditions on the KMC was analyzed. Here, we analyzed metagenome-assembled genomes (MAGs) of the Komagataeibacter, which is a predominant genus in KMC, to understand their roles in the KMC after exposure to Mars-like conditions (outside the International Space Station) based on functional genetic elements. We constructed three MAGs: K. hansenii, K. rhaeticus, and K. oboediens. Our results showed that (i) K. oboediens MAG functionally more complex than K. hansenii, (ii) K. hansenii is a keystone in KMCs with specific functional features to tolerate extreme stress, and (iii) genes related to the PPDK, betaine biosynthesis, polyamines biosynthesis, sulfate-sulfur assimilation pathway as well as type II toxin-antitoxin (TA) system, quorum sensing (QS) system, and cellulose production could play important roles in the resilience of KMC after exposure to Mars-like stress. Our findings show the potential mechanisms through which Komagataeibacter tolerates the extraterrestrial stress and will help to understand minimal microbial composition of KMC for space travelers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.3
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• pp.1100-1118
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• 2021

In a wide range of ML applications, the training data contains privacy-sensitive information that should be kept secure. Training the ML systems by privacy-sensitive data makes the ML model inherent to the data. As the structure of the model has been fine-tuned by training data, the model can be abused for accessing the data by the estimation in a reverse process called model inversion attack (MIA). Although, MIA has been applied to shallow neural network models of recognizers in literature and its threat in privacy violation has been approved, in the case of a deep learning (DL) model, its efficiency was under question. It was due to the complexity of a DL model structure, big number of DL model parameters, the huge size of training data, big number of registered users to a DL model and thereof big number of class labels. This research work first analyses the possibility of MIA on a deep learning model of a recognition system, namely a face recognizer. Second, despite the conventional MIA under the white box scenario of having partial access to the users' non-sensitive information in addition to the model structure, the MIA is implemented on a deep face recognition system by just having the model structure and parameters but not any user information. In this aspect, it is under a semi-white box scenario or in other words a gray-box scenario. The experimental results in targeting five registered users of a CNN-based face recognition system approve the possibility of regeneration of users' face images even for a deep model by MIA under a gray box scenario. Although, for some images the evaluation recognition score is low and the generated images are not easily recognizable, but for some other images the score is high and facial features of the targeted identities are observable. The objective and subjective evaluations demonstrate that privacy cyber-attack by MIA on a deep recognition system not only is feasible but also is a serious threat with increasing alert state in the future as there is considerable potential for integration more advanced ML techniques to MIA.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.15-26
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• 2021

Recently, as the introduction of cloud, mobile, and IoT has become active, there is a growing need for technology development that can supplement the limitations of traditional security solutions based on fixed perimeters such as firewalls and Network Access Control (NAC). In response to this, SDP (Software Defined Perimeter) has recently emerged as a new base technology. Unlike existing security technologies, SDP can sets security boundaries (install Gateway S/W) regardless of the location of the protected resources (servers, IoT gateways, etc.) and neutralize most of the network-based hacking attacks that are becoming increasingly sofiscated. In particular, SDP is regarded as a security technology suitable for the cloud and IoT fields. In this study, a new access control system was proposed by combining SDP and hash tree-based large-scale data high-speed signature technology. Through the process authentication function using large-scale data high-speed signature technology, it prevents the threat of unknown malware intruding into the endpoint in advance, and implements a kernel-level security technology that makes it impossible for user-level attacks during the backup and recovery of major data. As a result, endpoint security, which is a weak part of SDP, has been strengthened. The proposed system was developed as a prototype, and the performance test was completed through a test of an authorized testing agency (TTA V&V Test). The SDP-based access control solution is a technology with high potential that can be used in smart car security.

• Journal of the Korea Institute of Building Construction
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• v.22 no.4
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• pp.347-358
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• 2022

In order to satisfy the extraction and use of information such as estimates and processes required in the design and construction stages of BIM, which is an expectation of overall construction operation for the design and construction stage of domestic buildings, it is insufficient to supply and apply mobile technologies or terminals. In this paper, standardization of BIM-based processes from the design stage to the construction stage is proposed as an efficient construction system method through mobile-based simulation and test-bed case analysis review. The current status and potential of BIM application were identified through theoretical review of BIM and case studies at home and abroad. In addition, the overall flow of the project and the direction of effective process construction were investigated through each process by 3D, 4D, and 5D execution stage and the role of each collaborator. 4D building process BIM simulation system using mobile was implemented by applying a visualization engine that simulates process information, object information connection module, and related object information. Therefore, it was possible to minimize the possibility of re-construction of the BIM design and construction process model through the visualization of 2D drawings based on the 3D model of the building and the review of errors and interferences in the drawings. In addition, in the implementation of simulation for each process of the construction process through mobile devices, it was possible to support construction progress and process management according to the optimal option selected by the user.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.3
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• pp.249-277
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• 2023

The purpose of this study is to explore the potential contribution of citation metrics to improving the search performance of citation index databases. To this end, the study generated ten queries in the field of library and information science and conducted experiments based on the relevance assessment using 3,467 documents retrieved from the Web of Science and 60,734 documents published in 85 SSCI journals in the field of library and information science from 2000 to 2021. The experiments included re-ranking of the top 100 search results using citation metrics and search methods, query expansion experiments using vector space model retrieval systems, and the construction of a citation-based re-ranking system. The results are as follows: 1) Re-ranking using citation metrics differed from Web of Science's performance, acting as independent metrics. 2) Combining query term frequencies and citation counts positively affected performance. 3) Query expansion generally improved performance compared to the vector space model baseline. 4) User-based query expansion outperformed system-based. 5) Combining citation counts with suitability documents affected ranking within top suitability documents.

• The Korean Journal of Archival Studies
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• no.75
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• pp.177-212
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• 2023

Private archives are an important indicator of understanding a society that contains various memories, the lives and experiences of members, daily lives, morality, and values. Recently, as diversity has emerged as an important value in Korean society, a number of individuals and communities have been appeared based on different bases and purposes, and the contents, types, and categories of private archives produced from their voluntary activities have also diversified. These private organizations and communities are potential targets for producing and holding private archives, but most of them do not have the minimum infrastructure or system for management of archives, and the foundation for management of archives is weak only to be supported with the voluntary will and activities of the private sector. Therefore, there is a need for a plan to support activities to manage archives suitable for each organization's level while respecting the unique characteristics and methods of the private sector within the national management system of archives. In addition, since it is difficult to solve all issues related to management of archives in the private sector with only a small number of process topics, a cooperative system should be established to sustain activities to manage archives on its own through networks between private sectors. In this study, we intend to propose a 'private archives information network platform (hereinafter referred to as a platform)' as a way to establish a communication and network foundation between private sectors and share resources with each other. Based on the results of analysis of cases of building network between private sectors and expected user requirements, we would like to establish a vision and target model of the platform and discuss ways to continuously operate the platform.

• Journal of Service Research and Studies
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• v.13 no.1
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• pp.96-107
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• 2023

The objective of this study is to explore future issues that Chinese users, who have the highest mobile payment service usage rate in the world, will be most interested in. For this purpose, after collecting text data from a Chinese SNS site, it classifies major keywords into 4 types of future signals by using Keyword Emergence Map (KEM) and Keyword Issue Map (KIM). Furthermore, to understand the four types of signals in detail, it performs the qualitative analysis on text related to each signal keyword. As a result, it finds that the strong signal, which is rapidly growing in keyword appearance frequency during this research period, includes the keywords related to the daily life of Chinese people, such as buses, subways, and household account books. Additionally, it find that the signal that appears frequently now, but with a low increase rate, includes various services that can replace cash payment, such as hongbao (cash payment) and bank cards. The weak signal and latent signal, which appear less often than other two signals, includes the keywords related to promotion events or changes in service regulations. Its result shows that the mobile payment services greatly have changed user's daily life beyond providing convenience. Furthermore, it shows that, in the Chinese market, in which card payment is not common, the mobile payment services have the great potential to completely replace cash payment.

• Knowledge Management Research
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• v.23 no.4
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• pp.251-273
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• 2022

Metaverse is one of the most frequently used words recently, with digitalization accelerated by the COVID-19 pandemic that started in 2019 and the development of information and communication technology. It is expected to bring a new revolution in our life as a whole in user experience. In particular, as telecommuting was adopted in the business area, interest in virtual office services such as digital video conferencing and remote offices, which are similar to the metaverse, has also increased. In this study, a study on the intention to use the metaverse service used in the work environment was applied to the Unified Theory of Acceptance and Use of Technology 2(UTAUT2). External variables for metaverse characteristics, such as self-presentation, telepresence, and technostress, were analyzed and discussed. In this study, PC-based Gather.town and VR-based Facebook Horizon, currently the most well-known and considered usable in work environments, were introduced to potential users and conducted a survey. This study has academic implications in that the research has examined the factors that affect the technology acceptance intention of users who want to apply the metaverse as a work environment based on the UTAUT2 model, unlike previous studies that have been mainly researched on the general metaverse. In practice, it may be helpful to suggest factors that should be considered when firms adopt the metaverse for business purposes.