• Ocean Systems Engineering
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• v.2 no.3
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• pp.217-228
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• 2012

As the size of container ships continues to increase, not many existing harbors can host the super-container ship due to its increased draft and the corresponding dredging requires huge budget. In addition, the minimization of waiting and loading/offloading time is the most important factor in harbor competitiveness. In this regard, mobile-harbor concept has been developed in Korea to achieve much improved harbor capacity and efficiency. In developing the concept, one of the most important elements is the operability of crane between two or more floating bodies in side-by-side arrangement. The container ship is to be stationed through a hawser connection to an outside-harbor fixed-pile station with the depth allowing its large draft. The mobile harbors with smart cranes are berthed to the sides of its hull for loading/offloading containers and transportation. For successful operation, the relative motions between the two or more floating bodies with hawser/fender connections have to be within allowable range. Therefore, the reliable prediction of the relative motions of the multiple floating bodies with realistic mooring system is essential to find the best hull particulars, hawser/mooring/fender arrangement, and crane/docking-station design. Time-domain multi-hull-mooring coupled dynamic analysis program is used to assess the hydrodynamic interactions among the multiple floating bodies and the global performance of the system. Both collinear and non-collinear wind-wave-current environments are applied to the system. It is found that the non-collinear case can equally be functional in dynamics view compared to the collinear case but undesirable phenomena associated with vessel responses and hawser tensions can also happen at certain conditions, so more care needs to be taken.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.33-42
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• 2007

Mobile ad-hoc network(MANET) can increase independence and flexibility of network because it consists of mobile node without the aid of fixed infrastructure. But, Because of unrestriction for the participation and breakaway of node, it has the difficulty in management and stability which is a basic function of network operation. Therefore, to solve those problems, we suggest a distributed weighted clustering algorithm from a manageable and stable point of view. The suggested algorithm uses distributed weighted clustering algorithm when it initially forms the cluster and uses a concept which is distributed gateway and sub-cluster head to reduce the re-clustering to the minimum which occurs mobile nodes after forming the cluster. For performance evaluation, We compare DCA and WCA with the suggested algorithm on the basis of initial overhead, resubscriber rate and a number of cluster.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.95-110
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• 2018

With the widespread use of smartphones, various personal information of users is being recorded on a smartphone in real time. For the purpose of preventing the loss of important personal information of users, manufacturer provides a smartphone backup applications. Recently, not only backup programs for PC but also backup mobile apps for smart phones have been provided. From the point of view acquiring forensic data, it is important not to compromise the acquisition possibilities and the integrity of the original data. Especially, in the case of Android smartphones, various studies are being carried out to acquire the data without damaging the integrity of the original data. However, there are limitations to apply the existing research methods. In this paper, we describe the process of acquiring data using the backup mobile app provided by the manufacturer without compromising the integrity of the latest smartphone.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.63-68
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• 2018

Offloading is a method of communicating, processing, and receiving results from some of the applications performed on local computers to overcome the limitations of computing resources and computational speed.Recently, it has been applied in mobile games, multimedia data, 360-degree video processing, and image processing for Internet broadcasting to speed up processing and reduce battery consumption in the mobile computing sector. This paper implements a viewer that enables users to convert various flat-panel images and view contents in a wireless Internet environment and presents actual results of an experiment so that users can easily understand the images. The 360 degree spherical image is successfully converted to a plane image with Double Panorama, Quad, Single Rectangle, 360 Overview + 3 Rectangle depending on the image acquisition position of the 360 degree camera through the interface. During the experiment, more than 100 360 degree spherical images were successfully converted into plane images through the interface below.

• Korean Journal of Optics and Photonics
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• v.35 no.4
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• pp.164-169
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• 2024

We applied recursive numerical computation to create a basic design of a camera optical module for mobile phones. To enhance the resolution performance for a 38-degree field of view, we constructed the optical system with six non-spherical lenses. However, to increase its applicability to a compact mobile phone, we limited the overall length to 5 mm in the design. Using the data obtained from the basic design, we proceeded with optimization design using the Zemax design tool. The optimized optical system achieved a resolution performance with a modulation transfer function value of more than 19% for a 280 lines/mm pattern and image distortion within 1.0% for all wavelength rays. In this paper, we verify the feasibility of using recursive numerical computation for the basic design of a compact mobile phone camera.

• Journal of Intelligence and Information Systems
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• v.21 no.4
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• pp.53-77
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• 2015

Mobile commerce provides a convenient shopping experience in which users can buy products without the constraints of time and space. Mobile commerce has already set off a mega trend in Korea. The market size is estimated at approximately 15 trillion won (KRW) for 2015, thus far. In the Korean market, social commerce and open market are key components. Social commerce has an overwhelming open market in terms of the number of users in the Korean mobile commerce market. From the point of view of the industry, quick market entry, and content curation are considered to be the major success factors, reflecting the rapid growth of social commerce in the market. However, academics' empirical research and analysis to prove the success rate of social commerce is still insufficient. Henceforward, it is to be expected that social commerce and the open market in the Korean mobile commerce will compete intensively. So it is important to conduct an empirical analysis to prove the differences in user experience between social commerce and open market. This paper is an exploratory study that shows a comparative analysis of social commerce and the open market regarding user experience, which is based on the mobile users' reviews. Firstly, this study includes a collection of approximately 10,000 user reviews of social commerce and open market listed Google play. A collection of mobile user reviews were classified into topics, such as perceived usefulness and perceived ease of use through LDA topic modeling. Then, a sentimental analysis and co-occurrence analysis on the topics of perceived usefulness and perceived ease of use was conducted. The study's results demonstrated that social commerce users have a more positive experience in terms of service usefulness and convenience versus open market in the mobile commerce market. Social commerce has provided positive user experiences to mobile users in terms of service areas, like 'delivery,' 'coupon,' and 'discount,' while open market has been faced with user complaints in terms of technical problems and inconveniences like 'login error,' 'view details,' and 'stoppage.' This result has shown that social commerce has a good performance in terms of user service experience, since the aggressive marketing campaign conducted and there have been investments in building logistics infrastructure. However, the open market still has mobile optimization problems, since the open market in mobile commerce still has not resolved user complaints and inconveniences from technical problems. This study presents an exploratory research method used to analyze user experience by utilizing an empirical approach to user reviews. In contrast to previous studies, which conducted surveys to analyze user experience, this study was conducted by using empirical analysis that incorporates user reviews for reflecting users' vivid and actual experiences. Specifically, by using an LDA topic model and TAM this study presents its methodology, which shows an analysis of user reviews that are effective due to the method of dividing user reviews into service areas and technical areas from a new perspective. The methodology of this study has not only proven the differences in user experience between social commerce and open market, but also has provided a deep understanding of user experience in Korean mobile commerce. In addition, the results of this study have important implications on social commerce and open market by proving that user insights can be utilized in establishing competitive and groundbreaking strategies in the market. The limitations and research direction for follow-up studies are as follows. In a follow-up study, it will be required to design a more elaborate technique of the text analysis. This study could not clearly refine the user reviews, even though the ones online have inherent typos and mistakes. This study has proven that the user reviews are an invaluable source to analyze user experience. The methodology of this study can be expected to further expand comparative research of services using user reviews. Even at this moment, users around the world are posting their reviews about service experiences after using the mobile game, commerce, and messenger applications.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.151-156
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• 2013

Android that was made by Google and Open Handset Alliance is the open source software toolkit for mobile phone. In a few years, Android will be used by millions of Android mobile phones and other mobile devices, and become the main platform for application developers. In this paper, the integrated login application based on Google's Android platform is developed. The main features of the mobile combination login application content based on Android are as follows. First, the application has more convenient login functionality than the functionality of general web browser as the web browser of the mobile-based applications(web browser style applications) as well as security features and faster screen(view) capability by reducing the amount of data transfer. Second, the application is so useful for management of ID and Password, and it can easily manage multiple ID information such as message, mail, profile. The results of performance evaluation of the developed application show the functionality that can login many kinds of portal sites simultaneously as well as the ability that can maintain login continuously. Currently, we are trying to develope a couple of the technologies that can insert multiple accounts into one ID and check all information on one screen.

• Information Systems Review
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• v.8 no.2
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• pp.29-49
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• 2006

The introduction of the Digital Economy has formed a new market producing and trading information. Depending on the current contexts, each user evaluates identical information differently. It is difficult, even though important, to create and deliver the information customized to individual users by using some factors as time, location, and their personal characteristics. Information value, therefore, could be influenced by the capability of information systems to delivery useful information based on individual contexts to the right user immediately at the right time. From this point of view, we argue mobile systems which are able to be aware of individual contexts and deliver contextual information in real time can improve information value easily than other systems can. This research presents the results of an empirical test about antecedents to mobile advertising value. Though context relevance doesn't influence directly mobile advertising value, it plays an important role enhancing information usefulness which has great influence on mobile advertising value. Moreover, to supply information connected with users' context overcomes the effect of irritation. Lastly, entertainment can improve mobile advertising value as satisfying user's hedonic desire beyond the information source supporting decision making.

• The KIPS Transactions:PartC
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• v.8C no.6
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• pp.831-838
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• 2001

Mobile information service aims to provide some degree of effective information for real life activities of mobile users. Due to the user mobility and actual realism, it becomes very important technical issue to support an adaptive information service methodology to current situations of the terminal and/or user. This paper deals with a prefetching scheme for location-aware, out of the various context-aware which can be considered in mobile information service. It makes use of the velocity-based mobility model to shape the terminal and/or user's mobility behavior. Based on the moving speed and direction, the prefetching zone is proposed to define the number of prefetched information, so as to limit effectively the prefetched information whilst to preserve the location-aware adaptability. Using a simulator, the proposed scheme has been evaluated in the effectiveness point of view. The idea in this paper is expected to be able to extended to the other mobile service contexts, such as service time, I/O types of mobile terminals, network bandwidth.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.1
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• pp.32-38
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• 2011

Collisions of nearby ships are reported frequently because of bad weathers. A lot of efforts, using radar warning or other navigation security devices, were given to reduce the collisions, but the number of accidents could not be reduced. The main cause is that the ship personel are not watching carefully. In the paper, we propose a novel technique estimating the locations of nearby ships from their whistle blast and delivering the location information using mobile phones. We realized the technique using LabVIEW and showed its usefulness.