• Journal of Information Technology Services
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• v.22 no.2
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• pp.41-56
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• 2023

Metaverse is a three-dimensional virtual space where virtual and reality interact and co-evolutionize, and social, cultural, and economic activities are carried out in it to create value. Among the types of metaverse, the virtual world metaverse is expected to bring innovation beyond time and space in all areas of industry and society following the Internet. This study empirically analyzed factors affecting consumer's intention to use the virtual world metaverse by an innovation diffusion perspective. It was analyzed as an expanded technology acceptance model by setting relative advantages, ease of use, and visibility among the attributes of the innovation diffusion, and social presence, telepresence, and interactivity among the characteristics of the virtual worlds as factors. The proposed research model and hypothesis were verified through a PLS structural equation analysis based on a survey of 216 people. Studies have shown that relative advantage, telepresence, and interactivity have a significant effect on perceived usefulness and perceived enjoyment, but visibility does not have a significant effect on perceived usefulness and perceived enjoyment. It was found that ease of use had a positive effect on perceived enjoyment, social presence had a positive effect on perceived usefulness, and perceived usefulness and perceived enjoyment had a positive effect on the intention to use, respectively. This study is meaningful in that it empirically analyzed the factors affecting the intention to use the virtual world metaverse by dividing the psychological characteristics that induce consumer behavior into perceived usefulness which is an extrinsic motivation and perceived enjoyment which is an intrinsic motivation.

• Annual Conference of KIPS
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• 2011.04a
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• pp.171-174
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• 2011

서버 클러스터에서 부하 분산기는 사용자의 요청을 각 서버로 분산시키는 역할을 한다. 리눅스 가상 서버(LVS: Linux Virtual Server)는 소프트웨어적으로 사용되는 부하 분산기로서 여러 가지 스케줄링 방식들을 가지고 있다. 그러나 부하 분산 시에 서버의 유동적인 부하 정보를 반영하지 못하는 단점이 있다. 이에 개선된 방식으로 서버의 동시 연결 개수에 따라 상한계(Upper Bound)와 하한계(Lower Bound)를 설정하고, 요청을 분산하는 동적 스케줄링(Dynamic Scheduling)이 존재한다. 그러나 서버의 상태에 따라 상한계와 하한계가 바뀔 수 있음에도 불구하고 이 값들이 고정되어 있다는 단점을 가진다. 본 논문에서는 기존 부하 분산 방법의 단점을 극복하는 서버 전력 정보에 기반한 스케줄링 방식을 제안한다. 제안된 방식은 서버의 부하 정보를 기반으로 에너지를 추정하고 전력 수치를 기반으로 LVS의 가중치 테이블을 주기적으로 갱신한다. 그리고 부하 분산기는 클라이언트로부터 요청 받은 트래픽을 각 서버의 에너지 소모 상태에 따라 적용시킴으로써 에너지 소모가 최소화되도록 부하를 분산한다. 또한 서버의 상태에 따라 상한계와 하한계가 바뀔수 있음을 고려하여 상한계와 하한계를 설정하지 않고 서버의 상태에 따라 적절하게 요청이 분배되도록 하였다. 15대의 PC를 사용하여 실험을 수행하였으며, 실험 결과는 기존 부하 분산 알고리즘 중 성능이 가장 좋은 알고리즘에 비해 서버의 성능이 동일한 경우 성능 및 소비전력 면에서 거의 동등하였고, 서버의 성능이 상이한 경우 50.2% 성능 향상 및 27.3% 소비 전력 절감을 확인하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.3
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• pp.427-432
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• 2023

In this study, MEC (: Multi-access Edge Computing) proposes a cloud service network configuration for various tests of autonomous vehicles to which V2X (: Vehicle to Everything) is applied in Wave, LTE, and 5G networks and MEC App (: Application) applied V2X service function test verification of two domains (operator (KT, SKT, LG U+), network type (Wave, LTE (including 3G), 5G)) in a specific region. In 4G networks of domestic operators (SKT, KT, LG U+ and Wave), MEC summarized the improvement effects through V2X function blocks and traffic offloading for the purpose of bringing independent network functions. And with a high level of QoS value in the V2X VNF of the 5G network, the traffic steering function scenario was demonstrated on the destination-specific traffic path.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.2
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• pp.221-230
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• 2023

Purpose : This study was performed to evaluate the effects of virtual reality combined robot assist gait training (VRG) on improvement of balance and respiratory function in chronic stroke patients. Methods : A single-blind, randomized controlled trial (RCT) was conducted with 35 chronic stroke patients. They were randomly allocated 2 groups; VRG group (n=18) and conservative treatment group (CG; n=17). The VRG group received 30 minutes robot assisted gait training combined virtual reality training, robot assisted gait training was conducted in parallel using a virtual reality device (2 sessions of 15 minutes in a 3D-recorded walking environment and 15 minutes in a downtown walking environment). In the conservative treatment group, neurodevelopmental therapy and exercise therapy were performed according to the function of stroke patients. Each group performed 30 minutes a day 3 times a week for 8 weeks. The primary outcome balance and respiratory function were measured by a balance measurement system (BioRescue, Marseille, France), Berg balance scale, functional reach test for balance, Spirometry (Cosmed Micro Quark, Cosmed, Italy) for respiratory function Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), and maximum expiratory volume (PEF) were measured according to the protocol. The measurement were performed before and after the 8 weeks intervention period. Results : Both groups demonstrated significant improvement of outcome in balance and respiratory function during intervention period. VRG revealed significant differences in balance and respiratory function as compared to the CG groups (p<.05). Our results showed that VRG was more effective on balance and respiratory function in patients with chronic stroke. Conclusion : Our findings indicate that VRG can improve balance and respiratory function, highlight the benefits of VRG. This study will be able to be used as an intervention data for recovering balance and respiratory function in chronic stroke patients.

• Journal of Korean Physical Therapy Science
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• v.30 no.1
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• pp.62-71
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• 2023

Background: This study was performed to evaluate the effects of Thermal stimulation combined virtual reality training (TV) on improvement of upper extremity AROM and function in patient with chronic stroke. Design: Two groups pre-post randomized controlled design. Methods: A single-blind, randomized controlled trial was conducted with 30 chronic stroke patients. They were randomly allocated two groups; the TV group (n=15) and Virtual Reality training group (VT) (n=15). The TV group received treatment for 30 min - 15 min of Thermal stimulation, and 15 min of VR training. The VT group received 15 min of VR training. Each group performed 30 minutes a day 3 times a week for 8 weeks. The primary outcome upper extremity AROM and function were measured by a active range of motion test, Manual Function Test (MFT) and Jebsen-Taylor hand function Test (JTT). The upper extremity active range of motion was evaluated using a digital dual inclinometer. MFT and JTT were used to evaluate the hand function. The measurement were performed before and after the 8 weeks intervention period. Results: Both groups demonstrated significant improvement of outcome in muscle strength and upper extremity function during intervention period. TV group revealed significant differences in AROM and upper extremity function as compared to the VT groups (p<.05). Our results showed that TV was more effective on upper extremity AROM and function in patients with chronic stroke. Conclusion: Both groups demonstrated significant improvement of outcome in muscle strength and upper extremity function during intervention period. TV group revealed significant differences in AROM and upper extremity function as compared to the VT groups (p<.05). Our results showed that TV was more effective on upper extremity AROM and function in patients with chronic stroke.

• Composites Research
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• v.21 no.4
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• pp.7-14
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• 2008

Prediction of the load-bearing capacity of an adhesive-bonded Joint is of practical importance for engineers. This paper introduces interface fracture mechanics approach to predict the load-bearing capacity of composite metal bonded joints. The adhesion strength of composite/steel bonding is evaluated in terms of the energy release rate of an interfacial crack and the fracture toughness of the interface. Virtual track closure technique (VCCT) is used to calculate energy release rates, and hi-material end-notched flexure (ENF) specimens are devised to measure the interfacial fracture toughness. Bi-material ENF specimens gave consistent mode II fracture toughness $(G_{IIc})$ values of the composite/steel interface regardless of the thickness of specimens. The critical energy release rates of double-lap joints showed a good agreement with the measured fracture toughness. Therefore. the energy-based interfacial fracture characterization can be a practical engineering tool for predicting the load-bearing capacity of bonded joints.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.4
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• pp.135-142
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• 2023

Recently, many companies are using public cloud services or building their own data center because digital transformation is expanding. The software-defined storage is a key solution for storing data on the cloud platform and its use is expanding worldwide. Software-defined storage has the advantage of being able to virtualize and use all storage resources as a single storage device and supporting flexible scale-out. On the other hand, since the size of an object is variable, an imbalance occurs in the use of the disk and may cause a failure. In this study, a method of redistributing objects by optimizing disk weights based on storage state information was proposed to solve the imbalance problem of disk use, and the experimental results were presented. As a result of the experiment, it was confirmed that the maximum utilization rate of the disk decreased by 10% from 89% to 79%. Failures can be prevented, and more data can be stored by optimizing the use of disk.

• Journal of the Korea Society of Computer and Information
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• v.14 no.5
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• pp.93-102
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• 2009

Environmental monitoring applications measure temporature, humidity, and pollution degrees of large areas periodically and are essential for ubiquitous society. In this paper, we propose a sensor network MAC protocol that is applicable to environmental monitoring applications. The proposing MAC protocol has scalability by constructing multiple groups of sensor nodes as in SMAC protocol. Differently from SMAC protocol, however, ours have hierarchical structure between adjacent groups. Data transmission schedules are efficient since lower groups are synchronized to higher groups. Thus. the end-to-end delays and energy consumption can be reduced due to sequential transmission schedules. But since the nodes within the same group are synchronized to themselves. they have good adaptability and scalability compared to existing hierarchical approaches such as DMAC. We show by simulations that the proposing MAC protocol is superior to SMAC for environmental monitoring applications.

• Journal of IKEEE
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• v.26 no.1
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• pp.89-94
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• 2022

The W-band (75-110GHz) is a band that can utilize at least 10 times more bandwidth than the existing 5G band. Therefore, it is one of the bands suitable for future mobile communication that requires high speed and low latency, such as virtual and augmented reality. However, since the wavelength is short, it has a high path loss and is very sensitive to the atmospheric environment. Therefore, in order to develop a W-band communication system in the future, it is necessary to analyze the characteristics of path loss according to the channel environment. In this paper, to analyze the characteristics of the W-band path loss, the random forest technique was used, and the influence of the channel parameters according to the distance section was analyzed through the path loss data according to various channel environment parameters. As a result of the simulation, the distance has the highest influence on the path loss in the short distance, and the other channel environment factor is almost ignored. However, as the distance section became longer, the influence of distance decreased while the impact of clutter and rainfall increased.

• Journal of Digital Convergence
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• v.20 no.1
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• pp.301-307
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• 2022

Today, each broadcasting station makes the best use of CG (computer Graphics), which is the latest technology in election broadcasting, and competes to attract the eyes of viewers. This paper investigated the history of CG technology and design transitions in election ballot counting broadcasts from the perspective of CG designers. From the 1980s, when computer-based election ballot counting began, to the full-scale use of virtual studios, the image and technology produced by CG while watching the ballot-counting broadcast video of general elections, presidential elections, and local elections. We analyzed the utilization from various angles. In Korea, we started with the EDDS (Election Data Display System) developed in-house, created a database using a computer, and introduced manual animation CG every day from that time. After that, broadcasting stations focused on diverse and gorgeous CG image competition, and CG images were expanded from 2D to 3D while technology and design developed together. From 1985 to 1992, Korean broadcasting can be seen as a transitional period in which the image changes due to the emphasis on information power while utilizing digital technology.