• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.200-218
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• 2004

Online game business has emerged as the most lucrative entertainment industry, with over 10 million players in South Korea. The popularity of online games can be attributed to the availability of broadband network and the presence of numerous PC Bangs and around the country, which have pushed online games into the mainstream entertainment culture. The age distribution of online game players is expanding and a variety of new games are under development to target certain age groups. While the interactive entertainment market continues to expand, with many new online game publishers entering the market, relatively little is known about which factors influence online game players' behavioral intentions to play continuously in this area. It appears that in this extremely attractive and growing services segment, academics, as well as practitioners, would benefit from investigating the relationships among the players' loyalty, interactivity, the sense of presence and the impacts of several other key game-related constructs. Several types of interaction in on-line games and their relationship with the flow construct are investigated, and the resulting conceptual model is proposed. Based on data collected from online questionnaire survey, the validity of the simultaneous equation model has been tested and interesting conclusions have been developed concerning the relationships between the players' loyalty to the sense of presence flow, satisfaction and interactions. Other interesting results concerning game development strategy are also provided.

• Journal of Power Electronics
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• v.16 no.3
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• pp.1163-1175
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• 2016

In recent years, microgrids have been the focus of considerable attention in distributed energy distribution. Microgrids contain a large number of power electronic devices that can potentially cause negative impedance instability. Harmonic impedance is an important tool to analyze stability and power quality of microgrids. Harmonic impedance can also be used in harmonic source localization. Precise measurement of microgrid impedance and analysis of system stability with impedances are essential to increase stability. In this study, we introduce a new square wave current injection method for impedance measurement and stability analysis. First, three stability criteria based on impedance parameters are presented. Then, we present a new impedance measurement method for microgrids based on square wave current injection. By injecting an unbalanced line-to-line current between two lines of the AC system, the method determines all impedance information in the traditional synchronous reference frame d-q model. Finally, the microgrid impedances of each part and the overall microgrid are calculated to verify the measurement results. In the experiments, a simulation model of a three-phase AC microgrid is developed using PSCAD, and the AC system harmonic impedance measuring device is developed.

• International Journal of High-Rise Buildings
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• v.6 no.4
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• pp.297-300
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• 2017

Employers are realizing that workplaces have an immense impact on productivity. And, because people typically represent about 90% of a company's costs, even a slight improvement in productivity hits the bottom-line in a very big way. The focus is shifting away from saving money by reducing space needs or cutting energy requirements, and moving toward making the workplace friendlier and healthier. What is a healthy workplace, exactly? The answer should be clear by now. Mountains of research have expounded on this very topic, and then news outlets cover the latest discoveres ad infinitum. The problem is, research is rather dense, while the news isn't comprehensive. Office managers trying to improve workplace wellness want neither a 55-page report nor a half dozen articles to convince their landlord that their space can do better. Recognizing this gap, Harvard researchers have released a concise-yet-complete list of healthy building features. Here, we're sharing these nine features with a few insights of our own on the value of being healthy and productive. Find out: ${\bullet}$ What makes a healthy building and why is it so important ${\bullet}$ How to improve the health of your own office ${\bullet}$ What happens for your people and your bottom line when you make health a priority.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.128.2-128.2
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• 2012

Spectro-polarimetry is the most powerful technique for deducing the magnetic structure of the Sun. Stokes vector allow us to infer the physical conditions in the solar atmosphere prevailing during the line formation. Inversion codes are the main tool to extract this information from the Stokes spectra. This study will focus on measurements of the chromospheric He I 1083.0 nm triplet and the photospheric Si I 1082.7 nm line. A spectropolarimetric data set of sunspots, obtained with the German Vacuum Tower Telescope (VTT) at the Teide observatory on Tenerife, is analyzed using an inversion technique. We will introduce the German Vacuum Tower Telescope and the inversion code HeLix, and will show data sets that are analyzed by HeLix. Finally I made variety plots and maps for understanding photospheric and chromospheric layers of sunspots.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.7
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• pp.993-1004
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• 2002

This study was designed to examine the aesthetic characteristics of traditional wedding dress in Japan based on the internal$.$external aesthetics. They were extruded external and internal aesthetics based on pattern, color and fitting. The results of this study can be summarized as follows; Decorative characteristics in external aesthetics extracted into three factors; fantasticism, movement, amusement. The fantasticism was based on the omitted pattern, painting gold. The movement was presented through irregular composition, fitting method, and silhouette. The amusement was expressed through the composition focus on a near view and pattern reminded of bring up the image. Fitting characteristics in external aesthetics extracted into four factors; grace, cubic effect, optical illusion, and tradition. The pace was expressed through the weight, formativeness, and layered look The cubic effect was presented through spacing of belt and H-line silhouette. The optical illusion was based on the straight line of seam, V-pleats and straight silhouette of fitting, and high-waisted belt. The tradition expressed through the unchanged form since Heian-dynasty. Internal aesthetics were characterized by the naturalism and the moderation. The naturalism was presented through the natural pattern which based on subjective feeling, indignity and position of wearing man, and color based on taste. The necessaries, or pressed artificial moderation, were expressed through the clothing silhouette by simplicity.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.4
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• pp.251-265
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• 2013

The emergence of social network services, is changing the foundation of human relationship formation and method of communication of individuals through sharing of free information. Social network service is a service to support or facilitate an on-line extension of off-line network among people by helping them to share personal profile. History of social network services very short. But users of the various layers is increasing rapidly and ripple effect social as a result is very large. The focus of existing research was mainly devoted to motivation of use and acceptance of social network services. Currently the use of SNS was maturing. Thus, in-depth research on the use pattern of SNS users is needed. The purpose of this study is that, for Facebook in social network services, to analyze the changes in the initial stage of use, medium-term, usage patterns at the current time. Results of the study by analyzing the characteristics of the change in the pattern of usage of user of Facebook, it can be used as basic materials for SNS researchers and service provider.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.45.3-46
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• 2018

Oscillations in a sunspot are easily detected through the Doppler velocity observation. Although the sunspot oscillations look erratic, the wavelet analysis show that they consist of successive wave packets which have strong power near three or five minutes. Previous studies found that 3-min oscillation at the chromosphere is a visual pattern of upward propagating acoustic waves along the magnetic field lines. Resent multi-height observations help this like vertical study, however, we also focus on horizontal facet to extend three dimensional understand of sunspot waves. So, we investigate a fragmented sunspot expected to have complex wave profiles according to the positions in the sunspot observed by the Fast Imaging Solar Spectrograph. We choose 4 points at different umbral cores as sampling positions to determine coherence of oscillations. The sets of cross-correlation with three and five minutes bandpass filters during a single wave packet reveal interesting results. Na I line show weak correlations with some lags, but Fe I and Ni I have strong correlations with no phase difference over the sunspots. It is more remarkable at Ni I line with 3-min bandpass that all sets of cross-correlation look like the autocorrelation. We can interpret this as sunspot oscillations occur spontaneously over a sunspot at photosphere but not at chromosphere. It implies a larger or deeper origin of 3-min sunspot oscillation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.76-77
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• 2021

In line with the development of autonomous ships, it is necessary to train professional ship management supervisors to prepare for the transition to the ship's safety management system. Therefore, this study intends to investigate the capabilities required of ship management supervisors in preparation for introduction to autonomously operated ships for ship management supervisors in the field, and to suggest future capability development plans.

• Journal of Drive and Control
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• v.21 no.3
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• pp.1-8
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• 2024

Electric cart, one of the many devices created to aid golfers, combines software and wireless technology with over 200 different parts and computers. It is designed to be controlled remotely and can be started or stopped using a remote control while on the golf course. However, one recurring issue is the frequent derailment of the electric cart during operation. This problem not only hampers game performance but also causes delays as drivers lose focus. The objective of this study is to enhance the driving system of autonomous electric carts, which are controlled by the driver's signals, in order to address the issue of derailments. These autonomous carts follow a line tracer on the course. By examining the evolution of golf carts and the safety enhancements implemented in current models, we propose to supplement the autonomous driving system to increase safety and improve the performance of these electric carts.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.2
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• pp.152-161
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• 2019

This research carried out a study on the job characteristics of the skipper of the coastal composite fishing vessels in order to find a way to prevent the ship collision caused by the highest human error among the marine casualty of fishing boats. Video observation was used as the research method in which six CCD cameras were installed on the vessel to collect image data and data extracted from the image were analyzed to derive the results of the functional activity of skipper according to the fishing operation process of experimental fishing vessel. The results are as follows. The working process of the experimental fishing vessel consisted of navigation for fishing ground, setting line, waiting for hauling line, hauling line and navigation to homeport. In these processes, the skipper was performing watchkeeping in the wheelhouse in which he carried out a single task, a dual task that performed two tasks simultaneously, and a triple task that performed two or more tasks simultaneously. In addition, one of the risk factors causing the collision was a no watchkeeping in the wheelhouse for navigating for fishing ground, waiting for hauling line, and hauling line at 25.4%, 64.6% and 0.3%, respectively among the marine casualty while drowsiness caused 1.2% of the marine casualty in navigating for fishing ground. Concurrent tasks that simultaneously perform two or more tasks that can overlook any other important duties while carrying out watchkeeping in the wheelhouse include 51.3% of navigation for fishing ground, 81.9% of setting line, 19.0% of waiting for hauling line, 87.9% of hauling, and 88.7% of navigation to homeport. The above concurrent tasks yielded an average of 66.1%. Experimental fishing vessels are required to focus on ship handling operations related to fishery operations, and the skipper is assigned more activities and attention to fishery related tasks. Therefore, it is considered desirable to build a collision prevention system that is appropriate to the characteristics of the skipper's work, escaping from transferring the responsibility of ship collision to the skipper completely.