• Journal of Digital Convergence
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• v.15 no.9
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• pp.335-343
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• 2017

Several studies have suggested that lonely adolescents showed higher increases in stress and they easily addicted smartphone utilization for comforting loneliness and stress. Studies, moreover, have claimed that smartphone addiction has negative effects on mental health of adolescents. To contribute to knowledge on these topics, this study is to investigate to the relationship among adolescents' loneliness, stress, and smartphone addiction. To identify test subjects, the study conducted a survey that collected data from Korean adolescents, and the survey of this study was completed between April 1, 2017 and April 15, 2017. A total of 356 adolescents completed the survey, and the final data of empirical test of the study was 327. The empirical results demonstrate that the relationship between loneliness and stress of adolescents is mediated by four sub-factors of smartphone addiction such as difficulty of daily life, directivity of virtual life, withdrawal symptom, and tolerance. The results indicated that a smartphone addiction risk of adolescents was negatively related to their mental health, especially loneliness and stress.

• Journal of Industrial Convergence
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• v.18 no.1
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• pp.73-78
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• 2020

To analyze the main topics related to the use of blockchain technology, the Topic Modeling Technique was applied to the 'Blockchain Technology Utilization' big data shown in newspaper articles. To this end, from 2013 to 2019, when newspaper articles on the use of blockchain technology first appeared, the topics were extracted from 21 newspapers and analyzed by time to 15,537 articles. As a result of the analysis, articles related to the utilization of blockchain technology have increased exponentially since 2015 and focused on IT_science and economics. Key words related to cryptocurrency, bitcoin and virtual currency were weighted high, although they differed depending on time. Blockchain technology, which had focused on financial transactions, gradually expanded to big data, Internet of Things and artificial intelligence. As a result, changes in corporate topics were also made together to expand into various fields at banks for financial transactions, focusing on large and global companies. The study showed how these topics were changing, along with the main topics in newspaper articles related to the use of blockchain technology.

• Journal of Digital Contents Society
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• v.19 no.5
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• pp.853-860
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• 2018

The purpose of this study is to analyze the effectiveness of cooperative thinking and communication ability through gamified VR contents. For the experiment, we designed the Forum VR content using gamification approach and validated its effectiveness with a survey tool. The experiment was answered after 63 elementary school students played the Forum VR content. According to the survey results, Forum VR content has positive effects on the development of collaborative spirit and communication skills of elementary school students. Based on the results of this study, it is necessary to study the systematic and technical measures to spread VR contents at educational sites, and to differentiate them according to the characteristics of the curriculum for connecting various educational topics and VR contents.

• Journal of the Korea Society for Simulation
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• v.22 no.2
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• pp.53-62
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• 2013

Cloud environment is one in the field of distributed computing and it consists of physical nodes and virtual nodes. In distributed cloud environment, an optimal path search is that each node to perform a search for an optimal path. Synchronization of each node is required for the optimal path search via fast data transmission because of real-time environment. Therefore, a quantization technique is required in order to guarantee QoS(Quality of Service) and search an optimal path. The quantization technique speeds search data transmission of each node. So a main server can transfer data of real-time environment to each node quickly and the nodes can perform to search optimal paths smoothly. In this paper, we propose the quantization technique to solve the search problem. The quantization technique can reduce the total data transmission. In order to experiment the optimal path search system which applied the quantized data transmission, we construct a simulation of cloud environment. Quantization applied cloud environment reduces the amount of data that transferred, and then QoS of an application for the optimal path search problem is guaranteed.

• Journal of the Korean Society for Railway
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• v.12 no.3
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• pp.348-356
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• 2009

The objective of this paper is to estimate the DMT utility function for the transportation mode choice using SP survey. With the freight OD data the estimated utility function can be used as a basic data for forecasting DMT market. 3 alternatives of transportation mode are considered in SP survey; railway, road and DMT. The utility functions are developed according to the freight items, which are container, steel and chemical product. In this study the attribute variable are chosen as time, cost and reliability. The number of level for attribute variables are 3. The high valve is determined as +10% above the standard and the low value -20% below the standard.

• Korean Journal of Computational Design and Engineering
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• v.20 no.1
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• pp.75-83
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• 2015

In the virtual prototyping (VP) of digital products, it is important to provide the people involved in product development with the visualization and interaction of the products, and the simulation of their human machine interaction (HMI) behaviors in interactive 3D virtual environments. Especially, for the HMI behavior simulation, it is necessary to represent them properly and to play them back effectively according to user interaction in the virtual environments. In a conventional approach to HMI behavior simulation, user interface (UI) designers use UI design software tools to generate the HMI behavior of a digital product of interest. Due to lack of reusability of the HMI behavior, VP developers need to analyze and integrate it into a VP system for its simulation in a 3D virtual environment. As this approach hinders the effective communication between the UI designers and the VP developers, it is easy to create errors and thereby it takes significant time and effort especially when it is required to represent the HMI behavior to the finest level of detail. In order to overcome the shortcomings of the conventional approach, we propose an approach for representing the HMI behavior of a digital product using XML (eXtensible Markup Language) and for reusing it to perform the HMI behavior simulation in 3D virtual environments. Based on the approach, a VP system has been developed and applied for the design evaluation of various products. A case study about the design evaluation is given to show the usefulness of the proposed approach.

• The Journal of Society for e-Business Studies
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• v.8 no.4
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• pp.113-128
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• 2003

A Semantic Web based service description is to enable intelligent matchmaking of services by improving representational flexibility and expressiveness in service description for Web Services. Flexibility concerns the way of how a computer handles the discrepancies in the granularity and the structure of service description between different participants of web services. Expressiveness means richness in the semantic description of services (or ontological representation of each service as a concept). The main shortcoming of currently available industry standard framework for e-commerce such as UDDI and ebXML is that they do not allow much flexibility and expressiveness in the service description. In our research we analyze the requirements of extending service description based on the Semantic Web, especially in the context of DAML-S. We also propose a method to be applied to implement intelligent web services by implementing a virtual auction site, testAuction.com. Finally, we consider some theoretical issues regarding the framework for web services using ontology.

• The Research Journal of the Costume Culture
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• v.25 no.3
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• pp.301-314
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• 2017

This study focused on the movement adaptability of $19^{th}$ century classical opera stage costumes. Researchers focused on a basic $19^{th}$ century women's jacket. The study analyzed movement adaptability using ROM (range-of-motion) tests of the upper limb flexion and abduction postures. It developed two research garments to mimic basic $19^{th}$ century style jackets with or without gussets at the axilla. The ROM experiment identified the gusset size as 11cm in length. Experimental postures included upper limb flexion and abduction. The study measured subjective comfort at 8 postures. These postures included the flexion and abduction of the arms and torso. Subjects also evaluated the subjective comfort of the rotation posture of the torso. Researchers evaluated the similarities between research garments' silhouettes and the $19^{th}$ century women's jacket. The study used a 3D virtual fitting system to evaluate fit, and specialists further analyzed fit with photographs and 3D virtual graphics. The results are as follows. The silhouettes of both research garments were similar to the silhouettes of the $19^{th}$ century western women's jacket. The jacket with axilla gusset had a better fit than the basic style jacket. The basic style jacket without the axilla gusset showed limited movement adaptability at the shoulder joint and it caused discomfort at the axilla and elbow. The 3D virtual fit test was not a suitable method for analyzing silhouette similarity.

• Journal of KIISE
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• v.42 no.2
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• pp.213-219
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• 2015

Simulation is used these days to verify the hypothesis or the new technology. In particular, National Defense Modeling & Simulation (M&S) is used to predict wartime situation and conduct the military training. National Defense M&S can be divided into three parts, live simulation, virtual simulation, and constructive simulation. Live simulation is based on the real environment, which allows more realistic sumulation; however, it has decreased budget efficiency, but reduced depictions of reality. In contrast, virtual and constructive simulations which are based on the virtual environment, have increased budget efficiency, but reduced depictions of reality. Thus, if the three parts of the M&S are combined to make the L-V-C combined environment, the disadvantages of each simulation can be complemented to increases the quality of the simulation. In this paper, a method of interworking heterogeneous simulation middeware for L-V-C combined environment is proposed, and the test results of interworking between Data Distribution Service (DDS) and High Level Architecture (HLA) are shown.

• Journal of KIISE
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• v.43 no.9
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• pp.1026-1033
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• 2016

Path-finding on a grid map is a problem generally addressed in the fields of robotics, intelligent agents, and computer games. As technology advances, virtual game worlds tend to be represented more accurately and more realistically, resulting in an excessive increase in the number of grid tiles and in path-search time. In this study, we propose a path-finding algorithm that allows a prompt response to real-time queries by constructing a reduced state space and by precomputing all possible paths in an offline preprocessing stage. In the preprocessing stage, we vertically decompose free space on the grid map, construct a connectivity graph where nodes are the decomposed regions, and store paths between all pairs of nodes in matrix form. In the real-time query stage, we first find the nodes containing the query points and then retrieve the corresponding stored path. The proposed method is simulated for a set of maps that has been used as a benchmark for grid-based path finding. The simulation results show that the state space and the search time decrease significantly.