• Journal of Korean Library and Information Science Society
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• v.36 no.4
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• pp.5-25
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• 2005

This study is designed to research principles for establishing cooperatively virtual reference shelves of university libraries. To achieve the goal, this study establishes theoretical foundations for virtual reference shelves. Also, we discuss why the virtual reference shelves are necessary via cultural subject of libraries. Second, this study investigates current circumstances of virtual reference shelves' usages. This Investigation is conducted in terms of nine evaluation indexes. The results are used to justify the cooperative establishment for virtual reference shelves. Last, this study discusses actual methods and procedures for establishing cooperatively virtual reference shelves, associating with roles of related institutions.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.16
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• pp.267-293
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• 2001

The telecommunications-based information technology and the provision of electronic commerce are broadening possibility of the virtual enterprise. The purpose of this paper is to enhance academic and practical understanding virtual enterprise as one of the most promising new concepts in electronic commerce area. I strive to establish the concept of virtual enterprise as a strategic source of competitive advantage in small & medium business. I analyze several new trends and concepts in strategic business area which will eventually lead small & medium business to the virtual enterprise. It has great potential benefits for small & medium businesses which are placed in difficult circumstances. They must build IT infrastructure and make use of co-sourcing for the utilization of virtual enterprise. This paper also suggests the strategic methods which enable the conventional enterprise to introduce the virtual enterprise.

• Journal of the Korea Society of Computer and Information
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• v.23 no.7
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• pp.49-56
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• 2018

Virtual object weight perception is an important topic, as it heightens the believability of object manipulation in immersive virtual environments. Although weight perception can be achieved using haptic interfaces, their technical complexity makes them difficult to apply in immersive virtual environments. In this study, we present a visual pseudo-haptic feedback system that simulates and depicts the weights of virtual objects, the effect of which is weight perception. The proposed method recognizes grasping and manipulating hand motions using computer vision-based tracking methods, visualizing a Force Arrow to indicate the current lifting forces and its difference from the standard lifting force. With the proposed Force Arrow method, a user can more accurately perceive the logical and unidirectional weight and therefore control the force used to lift a virtual object. In this paper, we investigate the potential of the proposed method in discriminating between different weights of virtual objects.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2649-2666
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• 2015

In the dynamic cloud computing environment, to ensure, under the terms of service-level agreements, the maximum efficiency of resource utilization, it is necessary to investigate the online dynamic management of virtual machine resources and their operational application systems/components. In this study, the feasibility and properties of the division of virtual machine resources on the cloud platform, using the virtual machine cluster as the management unit, are investigated. First, the definitions of virtual machine clusters are compared, and our own definitions are presented. Then, the feasibility of division using the virtual machine cluster as the management unit is described, and the isomorphism and reconfigurability of the clusters are proven. Lastly, from the perspectives of clustering and cluster segmentation, the dynamics of virtual machines are described and experimentally compared. This study aims to provide novel methods and approaches to the optimization management of virtual machine resources and the optimization configuration of the parameters of virtual machine resources and their application systems/components in large-scale cloud computing environments.

• The Korean Journal of Emergency Medical Services
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• v.24 no.3
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• pp.55-63
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• 2020

Purpose: This study aimed to establish effective training strategies and methods by comparing the effects of 360° virtual reality video and first-person video in non-face-to-face practical lectures. Methods: This crossover study, implemented May 18-31, 2020, included 27 participants. We compared 360° virtual reality video and first-person video. SPSS version 25.0 was used for statistical analysis. Results: The 360° virtual reality video had a higher score of experience recognition (p=.039), vividness (p=.045), presence (p=.000), fantasy factor (p=.000) than the first-person video, but no significant difference was indicated for satisfaction (p=.348) or interest (p=.441). Conclusion: 360° virtual reality video and first-person video can be used as training alternatives to achieve the standard educational objectives in non-face-to-face practical lectures.

• PNF and Movement
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• v.10 no.2
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• pp.41-46
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• 2012

Purpose : This study investigated the effect of 4 weeks training of virtual reality game on balance and gait ability, depression of elderly people. Methods : The subjects of this study were 12 elderly people over 65 age. The subjects were treated by training using virtual reality gam (during 60 minutes, 3 times a week for 4 weeks). The results of the experiment were analyzed using paired T-test along with averages and standard deviations as the statistical methods for data analyses. Results : In comparison of depression, gait and balance ability between pre-test and post-test, there were statistically significant differences. Conclusion : Our study finding indicate that training using virtual reality game could improve balance and gait ability, depression in elderly people. According to our study, training using virtual reality game is judged to be used for elderly people with gait and balance problems, depression to prevent fall down.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.145-154
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• 2022

With the real museum changing from a center of viewing to a center of experience and communication, virtual museums have become independent as well as auxiliary and alternative roles for real museums. Therefore, it is necessary to review the concept and meaning of virtual museums and analyze the attributes of each exhibition type. This paper categorizes the exhibition types of virtual museums into four categories and analyzes the interaction methods of each exhibition type. The essential characteristics of interaction subjects affect all four types, but the method of virtual expression is distinguished, and the exhibition type that actively utilizes the virtuality of exhibition space and work expands the user's experience and communication. In this study, various forms and methods of construction of virtual museums can be explored by providing characteristics and considerations for each type of exhibition during the planning and construction of virtual museums.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.3
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• pp.233-246
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• 2022

Purpose : The study aims to determine the effects of virtual and non-virtual realities in a normal person's mirror walk on gait characteristics. Methods : Twenty male adults (Age: 27.8 ± 5.8 years) participated in the study. Reflection markers were attached to the subjects for motion analysis, and they walked in virtual reality environments with mirrors by wearing goggles that showed them the virtual environments. After walking in virtual environments, the subjects walked in non-virtual environments with mirrors a certain distance away after taking a 5 min break. To prevent the order effect caused by the experiential difference of gait order, the subjects were randomly classified into groups of 10 and the order was differentiated. During each walk, an infrared camera was used to detect motion and the marker positions were saved in real time. Results : Comparison between the virtual and non-virtual reality mirror walks showed that the movable range of the leg joints (ankle, knee, and hip joints), body joints (sacroiliac and atlantoaxial joints), and arm joints (shoulder and wrist joints) significantly differed. Temporal characteristics showed that compared to non-virtual gaits, the virtual gaits were slower and the cycle time and double limb support time of virtual gaits were longer. Furthermore, spacial characteristics showed that compared to non-virtual gaits, virtual gaits had shorter steps and stride lengths and longer stride width and horizontally longer center of movement. Conclusion : The reduction in the joint movement in virtual reality compared to that in non-virtual reality is due to adverse effects on balance and efficiency during walking. Moreover, the spatiotemporal characteristics change based on the gait mechanisms for balance, exhibiting that virtual walks are more demanding than non-virtual walks. However, note that the subject group is a normal group with no abnormalities in gait and balance and it is unclear whether the decrease in performance is due to the environment or fear. Therefore, the effects of the subject group's improvement and fear on the results need to be analyzed in future studies.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.982-986
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• 2005

Digital Manufacturing is a technology to facilitate effective product developments and agile productions by digital environments representing the physical and logical schema and the behavior of real manufacturing system including manufacturing resources, processes and products. A digital virtual factory as a well-designed and integrated environment is essential for successful applications of this technology. In this research, we constructed a sophisticated digital virtual factory by measuring and 3-D CAD modeling using parametric methods. Specific parameters of each objects were decided by object-oriented schema of the digital factory. It is expected that this method is very useful for constructions of a digital factory, and helps to manage diverse information and re-use 3D models.

• Communications for Statistical Applications and Methods
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• v.7 no.2
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• pp.489-497
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• 2000

The M/M/1 queue with impatient customers is studied. Impatient customers wait for service only for limited time K/0 and leave the system if their services do not start during that time. Notice that in the analysis of virtual waiting time, the impatient customer can be considered as the customer who enters the system only when his/her waiting time does not exceed K. In this paper, we apply martingale methods to the virtual waiting time and obtain the expected period from origin to the point where the virtual waiting time crosses over K or reaches 0, and the variance of this period. With this results, we obtain the expected busy period of the queue, the distribution, expectation and variance of the number of times the virtual waiting time exceeding level K during a busy period, and the probability of there being no impatient customers in a busy period.