• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.562-569
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• 2022

The alarm monitoring technology applied to existing operating ships manages data items such as temperature and pressure with AMS (Alarm Monitoring System) and provides an alarm to the crew should these sensing data exceed the normal level range. In addition, the maintenance of existing ships follows the Planned Maintenance System (PMS). whereby the sensing data measured from the equipment is monitored and if it surpasses the set range, maintenance is performed through an alarm, or the corresponding part is replaced in advance after being used for a certain period of time regardless of whether the target device has a malfunction or not. To secure the reliability and operational safety of ship engine operation, it is necessary to enable advanced diagnosis and prediction based on real-time condition monitoring data. To do so, comprehensive measurement of actual ship data, creation of a database, and implementation of a condition diagnosis monitoring system for condition-based predictive maintenance of auxiliary equipment and piping must take place. Furthermore, the system should enable management of auxiliary equipment and piping status information based on a responsive web, and be optimized for screen and resolution so that it can be accessed and used by various mobile devices such as smartphones as well as for viewing on a PC on board. This update cost is low, and the management method is easy. In this paper, we propose CBM (Condition Based Management) technology, for autonomous ships. This core technology is used to identify abnormal phenomena through state diagnosis and monitoring of pumps and purifiers among ship auxiliary equipment, and seawater and steam pipes among pipes. It is intended to provide performance diagnosis and failure prediction of ship auxiliary equipment and piping for convergence analysis, and to support preventive maintenance decision-making.

• Journal of Service Research and Studies
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• v.13 no.3
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• pp.57-69
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• 2023

Early morning delivery possesses distinct characteristics that differentiate it from standard delivery services. This service typically involves delivering products to customers during the early morning hours, primarily before 7 AM. While online early morning delivery offers various advantages from a customer perspective, it also presents challenges that sellers and online shopping companies need to overcome. The early morning delivery market is experiencing significant growth in the online food retail sector, incorporating both PC-based online shopping and mobile shopping. The objective of this research is to identify the factors influencing customer satisfaction and the intention to reuse in the context of early morning delivery for online shopping. To model the online shopping environment with early morning delivery, independent factors were categorized into three types: System Properties, Product Characteristics, and Delivery Characteristics. This study examined the relationships among these three independent factors, the mediating factor of customer satisfaction, and the dependent variable of the intention to reuse. To conduct this research, empirical validation of the research hypotheses was carried out using the final dataset for analysis. Within this study, the previously explored System Properties, Product Characteristics, and Delivery Characteristics were established. Summarizing the findings of the analysis, it was discovered that System Properties and Product Characteristics played a significant role in determining the quality of early morning delivery services for online shopping. While product diversity and convenience had a positive impact, it is noteworthy that Delivery Characteristics did not influence customer satisfaction. Consequently, it can be concluded that there is no effect on the intention to reuse.

• Journal of the Korea Society of Computer and Information
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• v.25 no.9
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• pp.183-191
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• 2020

Many learners are encountering e-Learning contents with smart devices and contents provides are carefully observing learners' reuse intention and behavior. Therefore, this study investigated the effect of e-Learning content platform characteristics on reuse intention for 200 users with smartphone-based e-Learning experience. The results show that the characteristics affecting reuse intention are content quality, interactivity, and ubiquity. Moreover, for men, only interactivity affects reuse intention, and for women, ubiquity and content quality affect reuse intention. When using smartphone-based e-Learning for less than an hour a day, only content quality affects reuse intention. On the contrary, ubiquity, convenience, and interactivity influence reuse intention when learning for more than one hour. Our results suggest meaningful implications that how e-Learning companies change their smartphone-based platform business strategy and how they utilize its key factors.

• The Journal of Information Systems
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• v.21 no.3
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• pp.71-97
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• 2012

There has been an upward trend in smartphone sales in Korea as well as the rest of the world. Even though smartphones are now at the peak of their popularity, the fact that they are somewhat limited in terms of their usages for certain purposes is unexpected. Precisely, compared to PC, smartphones typically have smaller display screens with a lower resolution, which make them difficult to use in general. For instance, when customers search the information about products in mobile shopping malls, due to the smaller screen with a low resolution smartphone users may realize that it is not easy and convenient not only to search the information, but also to read the information they found in the shopping malls. This restriction could become one of reasons that lowers the perceived quality of information in the shopping malls, which in turn leads to the reluctance to use the shopping malls. A comprehensive information systems (IS) literature review found that there has been little empirical evidence on perceived information quality that affects smartphone users' intention to use mobile shopping malls. The purposes of this study is to examine 1) the effects of perceived information quality on smartphone users' intention to use mobile shopping malls and 2) the relationships among behavioral beliefs in the middle of independent and dependent variables, such as information satisfaction, perceived usefulness, and customers' attitude toward mobile shopping. A survey was conducted in March 2012. College students and practitioners took participated in the survey. Structural Equation Modeling(SEM) was used for all data analysis. The results found that there is a strong relationship between perceived information quality and smartphone users' intention to use mobile shopping malls. In addition, this study also showed that there are strong relationships among behavioral beliefs. Further research is expected to validate the findings of this study and apply them in specific contexts.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.184-192
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• 2005

The best way to express space effectively on internet is to use 3D VR(Virtual Reality) contents. But it is too difficult to control the 3D VR space with the 2D device. So the content makers cannot solve this problem easily. Besides they define the UI control in their own subjective way which makes the users confused. The purpose of this study is to present the grounds for the Control UI standardization by studying the deriving improvement direction. First of all, we categorize current control UI designs for space-VR on web service by controlling method features into three Types. Next we itemize the main improvement direction that is based on our analysis. First, the UI design that maintains for a typical 2D Input Device method to help the beginner users. Secondly, the concise UI that allows users to Immerse easily in VR. Thirdly, the control level construction that satisfies both users who are skillful at 3D games and users who have little experience with these devices. In this way, we propose the most suitable control UI model that satisfies these improvement directions. We expect the result of our study to serve as an important basis for the standardization of VR services.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.6
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• pp.599-603
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• 2016

Recently the wireless LAN system is substituting wired LAN system notably as the number of mobile users increases greatly along the advancement of technology. But the wireless LAN has a critical weakness in the security such as data leakage. Thus a safe security system is imperative to avoid threatening from hackers with offering the best convenience to inner users. In this research, we have developed a RADIUS wireless LAN security system for industrial applications, which performs the EAP authentication with the compatibility for any maker of wireless LAN. The system has interfaces based on WEB, providing DB access function for user management so that users can perform authentication of 802.1x in their computers.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.568-574
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• 2013

In recent years, IT companies offer various cloud services using hardware-based technologies or software-based technologies. User can access these cloud services without the constraints of location or devices. The technologies are virtualization, provisioning, and big data processing. However, security incidents are constantly occurring even with these techniques. Thus, many companies build and operate private cloud service to prevent the leak of critical data. If virtual environment are different according to user permission, many system are needed, and user should login several virtual system to execute an program. In this paper, I suggest the access control method for application software on virtual operating system using the Open Authentication protocol in the Cloud system.

• The Journal of the Korea Contents Association
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• v.12 no.3
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• pp.480-486
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• 2012

There has been an increasing interest in new industry and demand creations by the convergence and integration between IT and infrastructure and BT, NT, and CT and the convergence of IT and spread of cloud computing have changed the IT service environment. Even in the educational field, the convergence and integration of contents with various IT have rapidly emerged and learning equipments for the educational purpose have expanded to the mobile media platform from PCs so that learning without limitations to time, place and equipment has become possible. Contents necessary for the smart education are under way by research development utilizing cyber reality and simulation, and 3D technologies. The purpose of this study is to propose marine contents use and service plans for the educational purpose in order to produce various types of contents for the marine life and environment, to improve the school achievement by stimulating interest and to provide individually customized learning.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.53-56
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• 2015

In this paper, we want provide improved services with faster transmission, IEEE 802.11n was standardized. A-MPDU (Aggregation MAC Protocol Data UNIT) is a vital function of the IEEE 802.11n standard, which was proposed to improve transmission rate by reducing frame transmission overhead. In this paper, we show the problems of TCP retransmission with A-MPDU and propose a solution utilizing the property of TCP cumulative ACK. If the transmission of an MPDU subframe fails, A-MPDU mechanism allows selective re-transmission of failed MPDU subframe in the MAC layer. In TCP traffic transmission, however, a failed MPDU transmission causes TCP Duplicate ACK, which causes unnecessary TCP re-transmission. Furthermore, congestion control of TCP causes reduction in throughput. By supressing unnecessary duplicate ACKs the proposed mechanism reduces the overhead in transmitting redundant TCP ACKs, and transmitting only a HS-ACK with the highest sequence number. By using the RACK mechanism, through the simulation results, it was conrmed that the RACK mechanism increases up to 20% compared the conventional A-MPDU, at the same time, it tightly assures the fairness among TCP flows.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.215-225
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• 2007

The portability and immediate communication properties of mobile devices such as UMPC influence the learning processes in interacting with peers, accessing resources and transferring data. This study explores the pedagogical potential of UMPC, being utilized in inquiry-based learning process in elementary school setting. Inquiry-based teaming, offering a powerful option for occasional projects and lab activities, is a style particularly well-suited for out-of-school programs because they have a freer hand to complement, enhance, and expand on the work that children are doing in their K-12 classes. A set of questionnaires measuring the level of interest and class achievement were answered by the students before and after the inquiry-based science class in elementary school. Statistical results show that most of the students prefer UPMC-based class to the traditional class. Some guidelines for effective UPMC-based class are also provided.