• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.5
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• pp.1-9
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• 2000

In this paper, for the reverse link of a imperfect power controlled DS/CDMA cellular system when a mobile radio channel is a Rayleigh distributed multipath fading channel, A extended DS/CDMA blocking probability formula considering both shadowing and multipath fading is derived. Erlang capacity and equivalent channel number considering shadowing are analyzed and compared with those considering both shadowing and multipath fading, respectively. The DS/CDMA blocking probability is calculated based on the analysis method that obtains Erlang capacity and ICF(interference correction factor) using the median value of $E_{b(i)}$/ $I_{0}$ corresponding to each reverse link user Assuming that the blocking probability set 2%, it is observed that the Erlang capacity is 19.97 Erlang at the data rate $R_{b}$=9.6 kbps and 11.67 Erlang at the data rate $R_{b}$=14.4 kbps and then is less 16% and 19% than the Erlang capacity considering shadowing only, respectively. It is also shown that the effect of multipath fading must not be ignored and then exact Erlang capacity and equivalent channel numbers that the DS/CDMA cellular system can support are provided.d.d.d.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.2
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• pp.111-118
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• 2011

It is not easy to define a boundary between TV and home computer in these day since developing H/W and S/W of computer technology induces that TV is conflated with computer. Coming digital HD broadcasting forces for replacement of TV at home and the trend of TV is became bigger. The evolved TV is able to replace the computer by connecting to the network and people want to do interactions with contents by using the bidirectional communication. Therefore, it is expected to changing the human lifestyle. It is natural that contents for all members of family are needed, since screen of TV become bigger. It is required that the contents should guarantees the accessability of information to the all of family members and the easy interaction with contents. But, the related basic research is not enough to catch the user's eye to induce flow or presence. Our goal of this study is to analyse effects of experiential space perception on performing interactive digital contents. The result shows that users interacted with contents without any difficulty when they met a same dimension and shape of objects as dimension and shape objects in their experiences or learning.

• Wind and Structures
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• v.30 no.4
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• pp.433-450
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• 2020

The strong turbulence characteristic of typhoon not only will significantly change flow field characteristics surrounding the large-scale wind turbine and aerodynamic force distribution on surface, but also may cause morphological evolution of coast dune and thereby form sand storms. A 5MW horizontal-axis wind turbine in a wind power plant of southeastern coastal areas in China was chosen to investigate the distribution law of additional loads caused by wind-sand coupling movement of coast dune at landing of strong typhoons. Firstly, a mesoscale Weather Research and Forecasting (WRF) mode was introduced in for high spatial resolution simulation of typhoon "Megi". Wind speed profile on the boundary layer of typhoon was gained through fitting based on nonlinear least squares and then it was integrated into the user-defined function (UDF) as an entry condition of small-scaled CFD numerical simulation. On this basis, a synchronous iterative modeling of wind field and sand particle combination was carried out by using a continuous phase and discrete phase. Influencing laws of typhoon and normal wind on moving characteristics of sand particles, equivalent pressure distribution mode of structural surface and characteristics of lift resistance coefficient were compared. Results demonstrated that: Compared with normal wind, mesoscale typhoon intensifies the 3D aerodynamic distribution mode on structural surface of wind turbine significantly. Different from wind loads, sand loads mainly impact on 30° ranges at two sides of the lower windward region on the tower. The ratio between sand loads and wind load reaches 3.937% and the maximum sand pressure coefficient is 0.09. The coupling impact effect of strong typhoon and large sand particles is more significant, in which the resistance coefficient of tower is increased by 9.80% to the maximum extent. The maximum resistance coefficient in typhoon field is 13.79% higher than that in the normal wind field.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.291-305
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• 2008

Previous study about Mobile Music Contents was mainly focused on Industry factors & enterprise factors like Technology. This study is not only focused on Technology factors, but also Customer & System factors like TAM of original, and also, this study first tried to find the Mobile Internet medium's customer purchase by each property's Mobile Music Contents from assorting the Mobile music Contents property and defining them. So to speak of this study have tried to concretely verify the factors of purchase. And also, I proposed an transformated model, and added independent variable factors, 'distinction', 'speed of system', 'speed of network', 'a career of use', 'amount of use', 'preservation', 'customization', 'information', 'confidence', 'omni presentation', 'potential possibility of reproduce'. By applying TAM this study has measured how the product property. user property, and system property causes effect to customer purchase of Mobile Music Contents. In results, First, success 8 factors were determined to be the purchase of 'Ringtone'. Second, 8 factors were determined to be the purchase of 'Ring-Back tone', but, 'The use of convenience' was not influenced 'Intention of Purchase'. Third, 6 factors were determined to be the purchase of 'Full Track Download of Music'. At the Conclusion this study presented a scheme that these study results could be applied in actual company and academic world.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.105-113
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• 2008

In Ubiquitous Society, accurate Location Calculation of user's device is required to achieve the need of users. As the location calculation is processed by ranging between transceivers, if some obstacles exist between transceivers, NLoS(Non-line-of-Sight) components of received signal increase along with the reduction of LoS(Line-of-Sight) components. Therefore the location calculation error will increase due to the NLoS effect. The conventional location calculation algorithm has the original ranging error because there is no transformation of ranging information which degrades the ranging accuracy. The Iterative Calculation method which minimizes the location calculation error relys on accurately identifying NLoS or LoS condition of the tested channel. We employ Kurtosis, Mean Excess Delay and RMS Delay spread of the received signal to identify whether the tested channel is LoS or NLoS firstly. Thereafter, to minimize location calculation error, the proposed Iterative Calculation method iteratively select random range and finds the averaged target location which has high probability. The simulation results confirm the enhancement of the proposed method.

• Management & Information Systems Review
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• v.32 no.1
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• pp.19-41
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• 2013

The primary purpose of this study is to identify the influencing factors on the acceptance behavior of user in smartwork. For this purpose, a research model and hypotheses are developed based on relevant literature reviews. The data have been collected from 320 potential users and respondents were employee of Daejeon and Chungnam region. The results of hypotheses testing through covariance structural model analysis are summarized as follows. First, individual innovativeness has positive influence upon perceived ease of use and acceptance intention of smartwork, and self efficacy has positive influence upon perceived ease of use. Second, subjective norm of social influence has positive influence upon perceived ease of use and image has positive influence upon perceived ease of use and perceived usefulness. Third, number of exception of task characteristics has positive influence upon perceived ease of use and autonomy has positive influence upon perceived usefulness. Lastly, perceived ease of use has positive effect on the perceived usefulness and acceptance intention, and perceived usefulness positively related to acceptance intention in smartwork. Based on the findings, this study ends with theoretical and practical implications, as well as limitations and future research directions.

• Journal of the HCI Society of Korea
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• v.12 no.3
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• pp.25-33
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• 2017

Current video service market doesn't satisfy the users' needs who want to find new and interesting contents despite the vast amount of contents. Now it is continuously necessary to Study on technology and using experience is continuously required in online video service area to stimulate the watching motivation efficiently with such as recommendation or promotion. One of efficient ways of increasing the using motivation is to give the users pleasure when they use the services. This study focused on 'unexpected funny finding' as a strategy of providing pleasure of using. It was believed that it could increase the pleasure of using the service, if serendipity, which means unexpected pleasure, accidental finding such as finding a beautiful $caf{\acute{e}}$ or meeting a friend at a certain place unexpectedly, is applied. This study defines the serendipity as 'contents that give unexpected pleasure' at the online video environment. First it theoretically extracted the various characteristics of serendipity through reading many books. Next it verified the other concept of serendipity through the diary of users' survey to additionally extract the characteristics of serendipity at video environment that are hard to find in books. It formed estimation items for the characteristics of the extracted serendipity and tested them in youtube to confirm the characteristics of serendipity being found in video service and observe potential factors that make it. As a result if verified and confirmed four factors that cause serendipity at video environment. This study could be used as basic data to understand the concept of serendipity. It has an academic meaning in the point that it could be a useful reference for the future study that analyzes the role or effect of serendipity at IT area including online video service.

• Journal of the Korea Convergence Society
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• v.8 no.4
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• pp.131-137
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• 2017

In the present study, we developed the 4D CT data generation program from CAD-based models. To evaluate the developed program, a CAD-based respiratory motion phantom was designed using CAD software, and converted into 4D CT dataset, which include 10 phases of 3D CTs. The generated 4D CT dataset was evaluated its effectiveness and accuracy through the implementation in radiation therapy planning system (RTPS). Consequently, the results show that the generated 4D CT dataset can be successfully implemented in RTPS, and targets in all phases of 4D CT dataset were moved well according to the user parameters (10 mm) with its stationarily volume (8.8 cc). The developed program, unlike real 4D CT scanner, due to the its ability to make a gold-standard dataset without any artifacts constructed by modality's movements, we believe that this program will be used when the motion effect is important, such as 4D radiation treatment planning and 4D radiation imaging.

• Journal of Navigation and Port Research
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• v.41 no.6
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• pp.423-436
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• 2017

This study examines the level of port service quality based on $Gr{\ddot{o}}nroos$(1984)'s Two-Dimensional Model: we investigated service-environment quality and service-delivery quality, and added service-product quality as a process quality. This study focused on a service user like a llner, forwarder, shipper, or a logistics firm using port service in the Port of Busan. We investigated relationships among the following vairables: service quality, customer satisfaction and port image; we also analyzed the path coefficients using Smart-PLS 3.0. The results and suggestions of this study are summarized as follows. First, all of the service quality variables influenced customer satisfaction but service-delivery quality didn't have an impact on port image. Secondly, there is correlation between customer satisfaction and port image; customer satisfaction had a positive effect with port image. Lastly, customer satisfaction and port image influenced the Relation Continuity Intention.

• Science of Emotion and Sensibility
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• v.15 no.1
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• pp.65-72
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• 2012

People receive information through various media, such as newspapers, TV, radio, magazines, or internet, etc. In particular, through the development of the internet and smart-phone they can interact with media and receive information in real time via handheld devices. However the types of information and media could affect the reliability of news information. In this study, it was the main interest how the usability in the new media with the interactivity, such as a desktop, tablet, and smart-phone affects the user's evaluation on the contents displayed by the different new media. Therefore, the present study was conducted to investigate the effect of the usability from the different display size of media and the different contents of articles on the reliability of information empirically. The results showed that the contents of the articles interacting with different devices affect the reliability of information. These findings propose the considerations on the effects of characteristic usability of the new media in the stages of the development of the media contents.