• Journal of Internet Computing and Services
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• v.16 no.4
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• pp.25-37
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• 2015

This study has developed a mobile AR contents Builder (MARB) featuring the augmentation of virtual objects, e. g. 2D images, 3D models and videos on user-preferred markers in mobile environment and with connected interaction events. The developed MARB is capable of augmenting multiple virtual objects on markers preferred by users, and selectively supporting many marker-specific interaction events. The MARB is also developed as a mobile App for convenience of use in the mobile environment. This makes users to implement AR contents by a GUI-based authoring procedure on the mobile device. The developed MARB allows App developers and general users to author mobile contents easily and can be applied to various field by those who wish to use diverse mobile AR contents. Moreover, the MARB will provide solutions for the expansion of mobile AR market, by overcoming the difficulties of mobile AR content development.

• Journal of Digital Contents Society
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• v.8 no.3
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• pp.323-328
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• 2007

Communication systems beyond 3G should provide more than 100 Mbps for wireless access. In addition to smart antennas, wireless multi-hop networks are proposed to increase the cell size and throughput. For example, Zigbee technology is expected to provide low cost and low power connectivity and can be implemented in wireless mesh networks larger than is possible with Bluetooth. Also, home embedded system using wireless mesh network is one of the key market areas for Zigbee applications. If the line-of-sight path is shadowed by home obstacles, a direct connection between the access point (AP) and the node is not possible at high frequencies. Therefore, by using multi-hop relay scheme the end node can be reached to AP. In this paper, the relaying of data between the AP and the end node is investigated and the throughput and PER(Packet Error Rate) are evaluated in multi-hop wireless mesh networks by using DSSS/BPSK system.

• Journal of Digital Convergence
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• v.13 no.11
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• pp.427-432
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• 2015

Recently, Mobile Social Network Game market has grown rapidly because Smart devices has been spreading to many people and improving performance. Push notification, which is a success factor of the mobile social network game brought about stress to the user. However, there is no study on push notifications in the mobile social network game; it was difficult to understand for the use of push notifications. The Games of Kakao talk platform has various push notification system and provides detailed descriptions. On the other hand, the game linked to Facebook has minimal push notification system. In the future, if game companies develop push notification system by the characteristics of user, mobile social network games be able to derive the user's use continuously.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.241-251
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• 2014

Mobile messenger services (MMSs), such as Kakaotalk, Wetalk, Line, and Whatsapp, are gaining popularity worldwide because of communicating with other people without any cost. We examined key antecedents of user loyalty to understand user's decision-making process in the MMS environment. To capture a long-term relationship with service providers, we posit relational commitment and user satisfaction as key predictors of user loyalty. Moreover, the effects of perceived usefulness, perceived enjoyment, and corporate image on user's decision-making processes were examined. The proposed model was tested by applying partial least squares to data from 220 experienced Kakaotalk users. The findings of this study found that both relational commitment and user satisfaction play an important role in enhancing user loyalty in the MMS context. The analysis results indicate that corporate image influences relational commitment and user loyalty through user satisfaction. The analysis results help MMS providers establish management or marketing strategies to effectively improve user loyalty.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.1
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• pp.85-91
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• 2009

Recently, the LCD has high market share in TV market. The use of motion images in portable devices like DMB, PMP and Cell Phone is growing rapidly. One of the technique of enhancing the LCD's characteristic which is the slow response time. But, the technique requires a lot of memory usage, because of the requirement of frame memory. In this paper, we propose a reduction method for the frame memory that is required for LCD overdrive. Proposed overdrive architecture based on modified DWT-Inverse DWT and Color Conversion. The proposed architecture has a considerable PSNR. At once, it uses 50% of frame memory size and reduces 15% of frame memory size compare with previous architecture. The design was implemented using Xilinx Vertex4 and had 2172 Slice except Memory.

• The Journal of the Korea Contents Association
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• v.20 no.6
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• pp.90-98
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• 2020

Modern vehicles are evolving from manual to automatic driving. As the ratio of electrical equipment and software increases inside the vehicle, vehicles that support autonomous driving are becoming another open computer system that can communicate with the outside. The safety of the vehicle means the safety of both the passenger and the non-passenger. It is not clear whether the safety problem of ultimate autonomous vehicles can be solved by the current solution of computer systems related to fault tolerance and security. Autonomous vehicles should not be dangerous to people after they are released to the market, so it is necessary to proactively diagnose all the risks that can be predicted with current technology. This paper examines the current developments of autonomous vehicles and analyzes their dangers that threaten driving safety, as well as their countermeasures.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.155-162
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• 2020

Among the fourth industrial revolution technologies, products related to healthcare using IoT and sensors are currently being developed. We design and develop an interaction system based on user standing posture recognition using multi-channel large area pressure sensors in this paper. To this end, first of all we investigate major sensor markets of the sensor industry and review technology trends and the current and future of smart healthcare. Based on this survey, we examine and compare cases developed at home and abroad for multi-channel large-area pressure sensors, which are key components of the system that we want to develop. We recognize the standing posture status of the user through the developed system and experiment with how effective it is actually in user posture calibration and apply the research results to various healthcare devices' medical fields based on this.

• Journal of the Korea Society for Simulation
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• v.28 no.4
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• pp.67-74
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• 2019

As the market for Internet of Things (IoT) service grows, the security issue of the data from IoT devices becomes more important. In this paper, we implemented a cryptographic library for confidentiality of sensor data from Android Things based IoT services. The library made use of the SEED algorithm for encryption/decryption of data and we verified the library by implementing a service environment. With the library, the data is securely encrypted and stored in the database and the service environment is able to represent the current sensing status with the decrypted sensor data. The contribution of this work is in verifying the usability of SEED based encryption library by implementation in IoT sensor based service environment.

• The Journal of the Korea Contents Association
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• v.15 no.7
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• pp.353-367
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• 2015

From the era of feature phone to the current smart phone which bloomed Social Network Games(SNGs), mobile games have held the top position as killer contents of mobile market. Mobile game has many constraints such as specification of device, network status, and external environment. Based on common perspective of game research, these factors have negative influences on flow of user. Even with these opinions, most mobile gamers have felt satisfaction. To explain this phenomenon, our research focuses on the constraints. Referring to theoretical concepts, we attempt to clarify the relationship between game features and flow through survey methodology. Our finding shows that the constraints have a positive effect on flow even though it disaccords with previous studies. Therefore, we argue that users of mobile game have sense of satisfaction not a cognitive overload as discomforts.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.682-686
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• 2006

There have been increasing interests in 3D mobile content service with emergence of a terminal equipping with a mobile 3D engine and growth of mobile content market. Mobile 3D Avatar is the most effective product displaying the character of a personalized mobile device user. However, previous studies on the method of expressing 3D Avatar have been mainly focused on natural and realistic expressions according to the change in facial expressions and lip shape of a character in PC based virtual environments. In this paper, we propose a method of synchronizing the lip shape with voice by applying a SMS message received in mobile environments to 3D mobile Avatar. The proposed method enables to realize a natural and effective SMS message reading service of mobile Avatar by disassembling a received message sentence into units of a syllable and then synchronizing the lip shape of 3D Avatar with the corresponding voice.