• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1A
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• pp.33-43
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• 2010

Recently, users want to use real-time multimedia services, such as internet, VoIP, etc., using their IEEE 802.11 wireless lan mobile stations. In order to provide such services, a handoff among access points is essential to support the mobility of a node, in such an wide area. However, the legacy handoff methods of IEEE 802.11 technology are easy to lose connections. Also, the recognition of a disconnection and channel re-searching time make the major delay of the next AP to connect. In addition, because IEEE 802.11 decides the selection of an AP depending only on received signal strength, regardless of a node direction, position, etc., it cannot guarantee a stable bandwidth for communication. Therefore, in order to provide a real-time multimedia service, a node must reduce the disconnection time and needs an appropriate algorithm to support a sufficient communication bandwidth. In this paper, we suggest an algorithm which predicts a handoff point of a moving node by using GPS location information, and guarantees a high transmission bandwidth according to the signal strength and the distance. We implemented the suggested algorithm, and confirmed the superiority of our algorithm by reducing around 3.7ms of the layer-2 disconnection time, and guaranteed 24.8% of the communication bandwidth.

• Journal of Digital Contents Society
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• v.19 no.1
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• pp.11-18
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• 2018

The Dutch treat culture, which pays for the cost of having meetings with a large number of people, is located in the daily life of many modern people. In particular, the execution of Kim Young-ran is a more active Dutch treat. However, when going dutch, there is a case where the amount of money to be paid per person is not divided equitably and there is an ambiguous situation about who should pay more. Also if one person have to pay all of the payments because of the different payment method such as a cash or card, there is inconvenience to keep a record of the financial relationship each time. In this paper, we introduce an application that allows several people to easily calculate the amount of money to pay per person when eating together or calculating something. From our service, you can easily access with web-based service, manage the user's debts more conveniently through forming the group. In addition, we focused on convenient calculation of cost by setting remaining unit and reserve function which is a function to overcome the disadvantages of existing application. Also, we maintain fairness through games in situations where the users need to make a choice.

• Spatial Information Research
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• v.15 no.3
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• pp.237-249
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• 2007

There are about 22,000 national control points throughout this nation. However, in order to identify the location data of a national control point, a control point result table is needed. And although the control points are important national facilities, due to the fact that these points located at remote areas such as on top of mountains, the facilities are being maintained via on-site inspection without any protections around them. In this research, by taking the locations where the control points are placed into consideration, a specialized RFID tags that can be attached to the national control point's marker has been developed, and CDMA-ready PDA based mobile Web System and national control point control system are developed as well. With help of these systems, control point data can be checked at the seen, and national control point maintenance personnel can find out about maintenance status and keep track of usage record. When these systems are taken into effect, access to the national control point data becomes easy, fast response to the change in data can be possible, and management efficiency will go up. When the Ubiquitous society becomes reality, the importance of location information will be high. Therefore, national control points using above mentioned RFID tags will not only be useful to the control point users and maintenance personnels such as professional land surveyors, but also useful when providing location based services to people, and it will become an important national infrastructure in terms of providing absolute location information.

• The Journal of Information Systems
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• v.24 no.1
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• pp.95-117
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• 2015

With the active smartphones user exceeding 500 million by the end of 2014, China has now become the largest smartphone market in the world. Smartphone companies provide variety of information through a range of applications, such as communications, entertainment, games, and so on. There were many studies conducted about the user acceptance and continuous intention of mobile service. However, it is still not quite clear what factors attract people to reuse smartphone in China. This paper examines the continuous intention of smartphone about Chinese customers. This study incorporates perceived enjoyment as a additional construct into a extended TAM model, by integrating a hedonic service of smartphone. We propose a research model that reflects the individual characteristics and usage contexts of smartphone, such as innovativeness, social influence, and service quality, and analyze the structural relationship between the main variables through empirical study. This study empirically investigated a research model and conducted a survey of smartphone service users in China. Our study proved that perceived enjoyment has a positive influence on continuous intention to use smartphone services. This paper provides the managers an insight that smartphone companies should take more consideration on how to provide more enjoyable service and attract customers to reuse their services.

• Journal of Digital Convergence
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• v.13 no.5
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• pp.177-185
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• 2015

The gender difference in social roles affects digital devices' utilization differences in man and woman even in the 21st Century. Prior studies analyze the digital divide (genders, ages, etc.) from the assessment perspectives of digital equipment, such as PCs. In the area of high speed internet, most functions of PCs have been replaced with smartphones, and around 80% of the mobile phone users adopt smartphones. Subsequently the inequality of physical access to the digital devices is no longer a criterion for digital divide. The focus on digital divide should be shifted from the physical access to other factors, such as socio-technical or socio-cultural ones. This paper examines utilization of women's digital equipment, in particular, preparing for tourism activities, which is popular but sensitive to the technology. A survey was conducted with participants of [Suncheon Garden Expo] 2013. The results of this study capture the inactive use of digital devices particularly women over 50s. This phenomenon (high utilization of the digital devices for social or informative purposes, but low utilization of the digital payment) implies other aspects of Korean women (economic independence, low self-assertion, technical difficulties, etc.), which is considered from the socio-technological convergence perspective. This study also has a practical implication on the side of the digital device developers as well as marketing, where the qualitative communication is likely to be incorporated for the women over 50s.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.19-25
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• 2020

As the number of mobile device users increases, research on various user authentication methods has been actively conducted to protect sensitive personal information. Knowledge-based techniques have the disadvantage that security is deteriorated due to easy exposure of authentication means, and proprietary-based techniques have a problem of increasing construction cost and low user convenience to use the service. In order to solve this problem, a FIDO authentication system, which is a user authentication method using a smart device, has been proposed. Since the FIDO authentication system performs authentication based on the biometric information of the user, the risk of the authentication means being leaked is low, and since the authentication information is stored in the user's smart device, the user information due to server hacking is solved. Through this, it is possible to select and utilize user authentication technology suitable for the security level of the service. In this paper, we introduce the FIDO authentication system, explain the main parts required for FIDO UAF client-server development, and show examples of implementation using UAF open source provided by ebay.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2093-2099
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• 2015

To prevent damage to the cargo, monitoring and remote management for reefer containers is necessary. The currently used remote monitoring service is the Power Cable Transmission(PCT) system, which is recommended by the International Maritime Organization(IMO). However, this system is not widely used because it requires a separate PCT infrastructure and is susceptible to data loss problems. To solve this problem, this study introduces the "IoT-based reefer container management system", The proposed system which is attached to reefer container collects and transmits data on the temperature, status and location of reefer container to middleware using RS-232 communication and WCDMA/GSM communication. Middleware is store the data received in the database and provide information to user in real time through the web and mobile program. At this time, users able to change setting temperature in real time from a distant place through the web program. This study tested by transit about shipment of strawberries to monitor and analyze and check the system's overall effectiveness.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1221-1230
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• 2004

In mobile environments, the locations of moving objects such as vehicles, airplanes and users of wireless devices continuously change over time. For efficiently processing moving object information, the database system should be able to deal with large volume of data, and manage indexing efficiently. However, previous research on indexing method mainly focused on query performance, and did not pay attention to update operation for moving objects. In this paper, we propose a novel moving object indexing method, named ACAR-Tree. For processing efficiently frequently updating of moving object location information as well as query performance, the proposed method is based on fixed grid structure with auxiliary R-Tree. This hybrid structure is able to overcome the poor update performance of R-Tree which is caused by reorganizing of R-Tree. Also, the proposed method is able to efficiently deal with skewed-. or gaussian distribution of data using auxiliary R-Tree. The experimental results using various data size and distribution of data show that the proposed method has reduced the size of index and improve the update and query performance compared with R-Tree indexing method.

• Cartoon and Animation Studies
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• s.36
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• pp.643-667
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• 2014

Recently, shooting photographs have become highly popular among general public and been used by various media such as digital camera, mobile, and kiosk. We could find that users prefer to Funology which is combined by fun and hardware technology on emotional point of view. Shooting photographs attracts user participation and makes effect of design to expand. The goal of this study is to classify user actions in a electronic kiosk which includes digital photography function based on the perspective of Funology and to bulit user behaviors model. Therefore user group model will be defined, and then interaction design guidelines of shooting photographs will be proposed. For this research, first of all, the concepts of Funology and user interaction with taking photographs are classified to three types which is based on literature investigation. Secondly, "Phodosee" kiosk is examined with Funology design elements which have been categorized beforehand. Then user's behaviors which are shown their interaction with "Phodosee" kiosk are observed and analyzed using video ethnography based on Funology perspectives. Finally, four persona models are suggested based on user's behaviors as follows; 1) to avoid being taken photography, 2) to try to shoot photography, 3) to participate shooting photography and 4) to lead others to take photography. To summarize this study, effects and limitations of Funology design elements using digital photography are discussed and guideline is suggested to improve user experience design.

• Journal of Broadcast Engineering
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• v.17 no.1
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• pp.152-164
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• 2012

DMB provides various kinds of data services such as BWS and TPEG service in addition to audio and video services. But recently the necessity of new business models creating profit has been on the rise due to the saturation of DMB receiver market and break-down of market barrier between mobile IPTV and DMB services. This paper introduces DMB filecasting service technology, which can be expected a new profit-creative business model. The purpose of DMB filecasting service is to transmit non-real time multimedia contents based on DMB AF format to the users through DMB channels. It makes possible to consume DMB contents with any DMB-installed device anytime, anywhere and share them with others. Also DMB filecasting service makes consumption and request of DMB contents possible to be extented to a variety of networks as well as DMB channels. The paper explains the standardization status of DMB filecasting service and various DMB filecasting service scenarios. And also it proposes a signalling methode, a transmission and reception protocol and a receiver structure using DMB broadcasting program guide information.