• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.1
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• pp.97-109
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• 2015

In this paper, we design and implement a two-way automatic communication system using a mobile instant messenger that can provide a customized service through a real-time two-way communication using a mobile instant messaging service. Two-way automatic communication system using a mobile instant messenger can improve the quality and quantity of information in real-time update of the information through the feedback. In addition, since it is communicated by using a mobile Instant Messanger in 1:1 there is no concerns that is recognized as spam, as well as it is possible to provide customized information for each user. Two-way automatic communication system using a mobile instant messanger shows the difference of the speed according to the data input time in typing by hands in result of comparing the time to input a date and the processing speed to search a data. Therefore in category treatment, command processing and natural language processing, Category treatment way is the most excellent in aspect of data processing speed, otherwise in aspect of the total speed to combine the data input time and the processing time, the command processing way is the best method.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.06a
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• pp.61-66
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• 2003

Mobile IP has been designed only to maintain communication as they move form place to place, so it doesn't guarantee Quality of Service(QoS). QoS in mobile IP is important to provide multimedia and real-time applications services in mobile, and it is closely related to handoff delay. Therefore, handoff delay problem is actively studied to guarantee QoS as a main issue in mobile IP research area Next generation Mobile IPv6 resolve this problem somewhat, triangle problem for first packet and handoff delay still remain. In this paper, we suggest SNMP Information-based routing that adds keyword management method to Information-based routing in active network in order to resolve such a problem, and then suggest QoS controlled handoff based on SNMP Information-Based routing. After modeling of suggested method and existing handoff method simulations we carried out with NS-2 for performance evaluation. The results of simulations show the some improvement on handoff delay, and therefore on QoS improvement.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.473-476
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• 2008

Mobile network environments are the environments where mobile devices are distributed invisible in our daily lives so that we can conventionally use mobile services at any time and any place. But, Mobile devices has a many security vulnerabilities caused by lower computing of devices and security problem of wireless network. So in this paper, PKI structure is proposed to minimize encrypting and decrypting operation by compounding session key and public key on WIPI environment. Proposed secure authentication system based on korean standard cryptography algorithm will give a more firmness in mobile network and support a more secure service for mobile academic information service that KISTI future plan.

• Journal of Information Processing Systems
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• v.15 no.5
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• pp.1082-1095
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• 2019

Camera calibration is an important part of machine vision and close-range photogrammetry. Since current calibration methods fail to obtain ideal internal and external camera parameters with limited computing resources on mobile terminals efficiently, this paper proposes an improved fast camera calibration method for mobile terminals. Based on traditional camera calibration method, the new method introduces two-order radial distortion and tangential distortion models to establish the camera model with nonlinear distortion items. Meanwhile, the nonlinear least square L-M algorithm is used to optimize parameters iteration, the new method can quickly obtain high-precise internal and external camera parameters. The experimental results show that the new method improves the efficiency and precision of camera calibration. Terminals simulation experiment on PC indicates that the time consuming of parameter iteration reduced from 0.220 seconds to 0.063 seconds (0.234 seconds on mobile terminals) and the average reprojection error reduced from 0.25 pixel to 0.15 pixel. Therefore, the new method is an ideal mobile terminals camera calibration method which can expand the application range of 3D reconstruction and close-range photogrammetry technology on mobile terminals.

• Educational Technology International
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• v.13 no.1
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• pp.101-144
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• 2012

Students mostly precede their learning without any direct support of instructor in e-learning and mobile educational environment. Many useful strategies and tools to facilitate self-regulated learning behaviors in e-learning environment have been introduced, yet, the limit has been reached by only suggesting self-regulated strategies with visual information in the most researches. Accordingly, this research is intent to propose the sound design strategies that facilitate learner's self-regulated learning behaviors in mobile learning environment. To achieve the objective of the research, two research questions are presented. First, what are the sound design strategies that facilitate the self -regulated learning behaviors in mobile learning environment?. Second, what are the results of evaluating the developed sound design strategies in terms of facilitating self-regulated learning behaviors?. To solve these research questions, the literature reviews on characteristics of mobile learning, concepts and features of self-regulated learning and sound were done to establish the sound design strategies. Through formative research method targeting instructional designers, sound design strategies were modified and supplemented. The research to validate these was performed and to verify the effect of the derived sound design strategies, the usability test aimed at instructional designer and learners was conducted. The final sound design strategies through this research process were six general design strategies and the sixteen detailed strategies. This research is meaningful because this offers the basic research on sound information design which has been lacking and help upgrade the upper limit of instructional design which mainly focused on visual information in mobile learning environment that shows information in a small screen.

• Journal of Information Technology Applications and Management
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• v.18 no.4
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• pp.21-40
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• 2011

Emoticons perform an important role as an enhancement to written communication, in areas such as Windows Live Messenger instant messaging, e-mails, mobile Short Message Services (SMS), and others. Emoticons are graphic images used in communications to indicate the feelings of people exchanging messages via mobile technology. In this research, the perceived usefulness of the emoticon in mobile phone text messages is verified with consumers using the five construct model of Huang. A K-means clustering technique for separating three groups based on levels of perceived usefulness of mobile emoticons is used with a structural equation model test using Smart PLS 2.0, and the bootstrap re-sampling procedure. We analyzed relationships among use of emoticons, enjoyment, interaction, information richness, and perceived usefulness. The results show there are relationships among use of emoticons, enjoyment, interaction, perceived usefulness, and information richness, however enjoyment of emoticons did not significantly affect the perceived usefulness of messages with emoticons alone. The results suggest emoticons have different affects on emotion in both mobile, and Messenger contexts. Our study did not consider more detailed media properties, and thus more studies are needed. Our research results contribute to mobile communication activation, provides companies with an understanding of key characteristics of consumers who use emoticons, and provides useful implications for improving management and marketing strategies.

• Spatial Information Research
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• v.11 no.1
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• pp.61-72
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• 2003

LBS has attracted considerable attention with the spread of high performance mobile devices and the expansion of mobile business. Our study starts from the recognition of the problems associated with the current mobile Sales Force Automation(SFA) which is one of the application domain of LBS: they lack the capabilities such as an efficient sharing of information. This paper presents a technical framework in which the location information on the move and the mobile P2P service are utilized for the realization of truly mobile SF A platforms. Major contributions of our study include feasible prototyping of gCRM middleware via which the location-based services on the move are enabled, and a agent module involving the P2P service for mobile clients.

• Asia pacific journal of information systems
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• v.15 no.2
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• pp.1-21
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• 2005

This study is an empirical study about the effects of perceived risks and perceived benefits on purchase intention in mobile commerce. Perceived risks and perceived benefits are proposed as mediators that make a significant impact on purchase intention in mobile commerce. Also, this study compared the direct effect of perceived risks, perceived benefits and consumer subjective knowledge to purchase intention. As antecedents of perceived risks and perceived benefits, subjective knowledge, mobile Internet familiarity, credibility for the purchase and provided information level are proposed and verified. Results from this study are as follows: First, the effect of perceived risks to purchase intention is not significant whereas that of perceived benefits is significant. Second, this study revealed that mobile Internet familiarity, credibility for the purchase and information level are significantly related to mobile purchase intention through perceived benefit. Third, subjective knowledge makes a significant impact on purchase intention directly not mediated by perceived risk or perceived benefit. Based on these results, managerial implications for mobile commerce vitalization and marketing strategy are discussed. Finally, limitation for this research and further research issues are suggested.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.852-862
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• 2013

This paper proposes a target tracking control method for wheeled mobile robots with nonholonomic constraints by using a backstepping-like feedback linearization. For the target tracking, we apply a vision system to mobile robots to obtain the relative posture information between the mobile robot and the target. The robots do not use the sensors to obtain the velocity information in this paper and therefore assumed the unknown velocities of both mobile robot and target. Instead, the proposed method uses only the maximum velocity information of the mobile robot and target. First, the pseudo command for the forward linear velocity and the heading direction angle are designed based on the kinematics by using the obtained image information. Then, the actual control inputs are designed to make the actual forward linear velocity and the heading direction angle follow the pseudo commands. Through simulations and experiments for the mobile robot we have confirmed that the proposed control method is able to track target even when the velocity sensors are not used at all.

• Journal of Korean Elementary Science Education
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• v.39 no.1
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• pp.40-53
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• 2020

This study analyzed the features of norms formed in mobile-based science problem-solving and interpreted them from the perspective of digital citizenship. For this, we implemented two mobile-based science problem-solving activities for nine elementary school preparatory teachers composed of two groups, and analyzed the norms observed in their activities. As a result, four norms were found as follows. First, the information presented as a basis should be scientifically reliable. Second, the information need to be searched widely, but the information should be selected and reconstructed in relation to the problem. Third, in a mobile environment, the ideas should be clearly expressed and understood. Fourth, courtesies in mobile interaction should be represented more politely than in face-to-face interaction. Based on the four norms found in this study, we discussed the characteristics and factors of digital citizenship for judging scientifically reliable and relevant information and expressing ideas clearer in mobile environment. Finally, we suggested the educational implications for fostering digital citizens who can judge and practice 'science issues' in a 'mobile environment'.