• KIPS Transactions on Software and Data Engineering
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• v.4 no.12
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• pp.561-570
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• 2015

With the advance of IT technology, contents from digital multimedia devices and softwares are widely used and distributed. However, novice uses them for illegal purpose and hence there are needs for protecting contents and blocking illegal usage through multimedia forensics. In this paper, we present a forensic technique for identifying digital imaging source using sensor pattern noise. First, the way to acquire the sensor pattern noise which comes from the imperfection of photon detector against light is presented. Then, the way to identify the similarity of digital imaging sources is explained after estimating the sensor pattern noises from the reference images and the unknown image. For the performance analysis of the proposed technique, 10 devices including DSLR camera, compact camera, smartphone and camcorder are tested and quantitatively analyzed. Based on the results, the proposed technique can achieve the 99.6% identification accuracy.

• Current Optics and Photonics
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• v.1 no.5
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• pp.474-490
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• 2017

Since the recent slowdown in the smartphone market, studies for wearable devices are briskly being carried out to find new markets, such as virtual reality devices. In this paper, a head-mounted display (HMD) which provides expanded virtual images before human eyes by enlarging images of a small display was designed, and the tolerance analysis method for a focus-adjustable HMD based on afocal optical systems was studied. There are two types of HMDs: a see-through type that allows the user to view the surroundings, and a see-close type where the user can only view the display screen; the former is used in this study. While designing the system, we allowed a lens within the system to be shifted to adjust its focus from +1 to -4 D (diopters). The yield of the designed systems was calculated by taking the worst-case scenario of a uniform distribution into account. Additionally, a longitudinal aberration was used rather than MTF for the tolerance analysis with respect to system performance. The sensitivity of the designed system was calculated by assigning a certain tolerance, and the focus lens shift was calculated to adjust the image surface variations resulting from the tolerance. The smaller the tolerance, the more expensive the unit price of the products. Very small tolerances may even be impossible to fabricate. Considering this, the appropriate tolerance was assigned; the maximum shift of the focus lens in which the image surface can be adjusted was obtained to find the changes in aberration and a good yield.

• Convergence Security Journal
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• v.12 no.3
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• pp.123-129
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• 2012

Due to the high digital technology, various devices such as TV, PC, smartphone, and pad computer are connected to each other using internet and under the circumstance internet services of which the running platforms are mainly PC become "N-screenlized" by extending their service platform to non-PC devices. As a digital TV has outstanding features of being the most influential device in the living room and having the wide spectrum of users, several internet services has been ported on the digital TV platform (in the form of data services) in order to enhance their brand powers. Most of the services, however, failed to get a satisfactory results as the data services are defeated by the broadcasting contents in the competition for the viewer's interests. In the paper, the design guidelines that make data services not to compete with the broadcasting contents are proposed and a prototype of a data service that accommodates the guidelines is introduced. The prototype, called "TV ideal-type world-cup", does not disturb a viewer's watching broadcast contents and channel-changing behavior while it is running and its service flow is designed for a viewer to achieve the goal of service in a few minutes so that the viewer can enjoy the service in a commercial period.

• Journal of the Korea Convergence Society
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• v.8 no.4
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• pp.25-36
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• 2017

As smartphone users have increased in recent years, various applications have been developed and used especially for Android-based mobile devices. However, malicious applications developed by attackers for malicious purposes are also distributed through 3rd party open markets, and damage such as leakage of personal information or financial information of users in mobile terminals is continuously increasing. Therefore, to prevent this, a method is needed to distinguish malicious apps from normal apps for Android-based mobile terminal users. In this paper, we analyze the existing researches that detect malicious apps by extracting the system call events that occur when the app is executed. Based on this, we propose a technique to identify malicious apps by analyzing the sequence similarity of kernel layer events occurring in the process of running an app on commercial Android mobile devices.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6B
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• pp.618-630
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• 2011

Mobile RFID system, that consists of the existing RFID reader mounted on the mobile devices such as smartphones, is able to provide the users a variety of services and convenience. Although the users can get the information about a certain product anytime anywhere, there is high probability that their privacy may be violated because their belongings with RFID tags can be scanned by other mobile readers at any time. Several RFID authentication schemes have been proposed to deal with these privacy issues. However, since the existing solutions require heavy computation on the tag side, most of them is not applicable to the general low-cost passive tags which do not have any processing unit. In this paper, we propose the efficient authentication scheme for mobile RFID system applicable to the passive tags as well as the active ones by the best use of computing capability of mobile devices. The proposed scheme satisfies the import security issues such as tag protection, untraceability, anti-traffic analysis. We also implement the proposed scheme on top of real smartphone for feasibility and show the experimental results from it.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.2
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• pp.109-118
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• 2012

As a result of the prevalence of smartphone, various mobile services became faster by LTE networks. Because many mobile devices are used more wireless services, heavy signaling traffic for authentication could be generated. Authentication is an important factor in wireless networks to identify devices; it is the start of wireless networks. This paper analyzes previous patterns for more effective authentication in accessing of another external networks. We propose a fast authentication scheme for minimizing of signaling cost between the authentication server and external networks. And we calculate the rate of authentication occurrence in LTE networks using mathematical modeling as well as the change of signaling cost for authentication in various network environments. Finally, we calculate the optimized number of authentication data and show the effectiveness for authentication signaling costs.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.91-95
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• 2014

We could use a social networking service such as data communication, personalized service through smart devices as Tablet computers and smart phones. Because of these characteristics, suitable lectures are provided to mobile device. especially, in Korea Cyber University already had built a lot of infrastructures. But, many mobile devices are used in a small display environment. it could effect on reduce Students' efficiency from taking courses. Therefore, we need effectively in a small display content layout for overcome these problems. In this paper, proposed the platform for Improve learning effect in smartphone education. It studied based on golden section and golden spiral theory. and also, we developed layout for content development using vector method illustration program.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.11
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• pp.2119-2124
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• 2016

The Internet of things (IoT) needs to be an event-driven approach for efficient related time response and processing. The growth of mobile devices in Internet of Things (IoT) leads to a number of intelligent buildings related IoT applications. For instance, home automation controlling system uses client system such web apps on smartphone or web service to access the home server by sending control commands. The gateway based RESTful technology responsible for handling clients'requests attests an internet latency in case a large number of clients' requests submit toward the gateway increases. In this paper, we propose the design tasks of the IoT gateway for handling concurrency events. The gateway based event-driven architecture is designed for building IoT gateway using node.js on one side and communication protocol based message-oriented middleware known as XMPP to handle communications of intelligent building control devices connected to the gateway through a centralized hub.

• Journal of Internet Computing and Services
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• v.17 no.6
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• pp.41-51
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• 2016

The appearance of 3D-Touch interface provided the basis of a new interaction method between the users and the mob ile interface. However, only a few smartphones provide 3D-Touch features, and most of the 2D-Touch devices does not provide any means of applying the 3D-Touch interactions. This results in different user experiences between the two interaction methods. Thus, this research proposes the Virtual Force Touch method, which allows the users to utilize the 3D-Touch Interface on 2D-Touch based smart devices. This paper propose the suitable virtual force touch mechanism that is possible to realize users' inputs by calculating and analysis the force touch area of users' finger. This proposal is designed on customized smartphone device which has 2D-Touch sensors.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.845-847
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• 2014

In recent years, the mobile OS market, enlargement and, at the same time, Android has mounted various smart phones and feature air conditioning, smart TV, cleaning robot, camera, etc. that the number is being spread at a rapid pace. But a lot of devices to control the modules and applications at once, this is not a device for controlling the dissemination of applications all in one place, and in charge of the devices that allow you to manage applications are lacking. Accordingly, in this paper, use the Web Server registered in the appliance can be controlled by management, Web access, is proposing and designing the system. This is the current research is actively in progress in the field of IoT (Internet of Things) would be utilized.