• Journal of Digital Convergence
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• v.13 no.12
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• pp.179-185
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• 2015

Along with the recent advances of mobile internet technology, use of social network service(SNS) is very common among adolescents or college students in their daily lives. Although there have been a lot of studies on Internet addiction or mobile phone addiction, however, there were little research on SNS addiction so far. Scholars investigated somewhat broader and obscure phenomenon of Internet addiction. In this regard, the current study tried to examine factors which influence SNS addiction behavior. Unlike Internet addiction, there are positive influencing factors such socialization, enjoyment as well as problematic ones like loneliness. Data were collected from college students in Korea to examine how those factors influence addiction behavior and hypotheses were tested using the partial least square method. All three factors, socialization, enjoyment, and loneliness, were found to significantly influence SNS addiction and socialization was positively associated with enjoyment.

• Spatial Information Research
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• v.18 no.3
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• pp.53-62
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• 2010

Recent development in wireless communication technology, like GPS, and mobile equipments, like PDA and cellular phone, make location-based services (LBSs) popular. However, because, users continuously request a query to a server in the LBSs by using their exact locations, privacy information could be in danger. Therefore, a mechanism for users' privacy protection is required for the safe and comfortable use of LBSs by mobile users. For this, we, in this paper, propose a grid-based cloaking area creation scheme supporting continuous LBSs in peer-to-peer environment. The proposed scheme creates a cloaking area by using Chord protocol, so as to support the continuous LBSs in peer-to-peer environment. Finally, we show from a performance analysis that our cloaking scheme outperforms the existing cloaking schemes, in terms of service time.

• The Journal of the Korea Contents Association
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• v.10 no.10
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• pp.86-93
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• 2010

With the introduction of smart phones, the augmented reality became popular and is increasingly drawing attention. The augmented reality in the mobile devices is becoming an individual area to study. Many applications of the augmented reality have been studied, but there are just a few studies on its combination with artificial intelligence in games. In this study, an artificial intelligence algorithm was proposed, which dynamically converts the state of the 3D agent in the augmented reality environment using the 3-Axis acceleration sensor in the smart phone. To control the state of the agent to which the artificial intelligence is applied, users used to directly enter the data or use markers to detect them. The critical values, which were determined via test, were given to the acceleration sensor to ensure accurate state conversion. In this paper, makerless tracking technology was used to implement the augmented reality, and the state of the agent was dynamically converted using the 3-Axis acceleration seonsor.

• Journal of electromagnetic engineering and science
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• v.15 no.3
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• pp.151-157
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• 2015

The increasing use of mobile phones has raised public concern about the possible biological effects of radiofrequency electromagnetic field (RF-EMF) exposure on the human brain. To investigate the potential effect of RF-EMF exposure on the brain, we examined the behaviors and hippocampal morphology of C57BL/6 mice after sub-chronic exposure to RF-EMFs with a relatively high SAR level (5.0 W/kg). We applied a 2-hour daily exposure of WCDMA 1,950 MHz using a reverberation chamber that was designed for whole-body exposure for 60 days. In the behavioral tests, RF-EMF did not alter the physical activity or long-term memory of mice. Moreover, no alteration was found in the neuronal and glial cells in the hippocampus by RF-EMFs. In this study, we showed that sub-chronic whole body RF exposure did not produce memory impairment and hippocampal morphological alteration in C57BL/6 mice.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.3
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• pp.291-300
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• 2004

Due to the rapid growth of mobile communication services, many studies have been performed on the biological effects of EMF(Electromagnetic field) exposure. However, it is not easy to create the field uniformity in radio frequency. To overcome this difficulty, the electric field and SAR(Specific Absorption Rate) distribution is developed to measure the whole body exposure system. In this paper, we developed the whole body exposure system for in-vivo study utilizing reverberation chamber which has a high possibility of practical use by substituting previous the EMC chamber. The field uniformity in the test area of the designed reverberation chamber was satisfied by the simulation and measurement data. In animal study of the whole body exposure for a mouse, the results of FDTD simulation were compared with those of measurement to confirm SAR under the electromagnetic exposure. We analyze the electric field distribution in the interior of the reverberation chamber and treat these results in statistical manner. In the CDMA frequency band(PCS ＆ Cellular band), an average value of the whole body SAR and local peak value for a experimental mouse were presented for various input power.

• Journal of Broadcast Engineering
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• v.13 no.4
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• pp.528-543
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• 2008

Internet Protocol Television (IPTV) provides an interactive and personalized service for realizing integrated broadcasting and telecommunication services. Set-top box (SIB) connected to TV is an essential component required for IPTV and has a unique hardware identifier used in identification and authentication. It means that subscriber authentication based on box-level identification is inconsistent with IPTV's main intention of providing personalized services. The proposed solution is to provide an opportunity to use the flexible user-centric authentication mechanism through Java Card applets in IPTV application server and 3G networks. This paper suggests personalized services by moving the user's private data and authentication management beyond the STB to a truly personalized device, the ubiquitous mobile phone. In addition, this paper presents effectiveness and security analysis for verifying the proposal.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1876-1882
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• 1999

In this paper, we have proposed a FCB detection algorithm for the GSM system which is european cellular standard. The detection algorithm can be implemented using received signal sampler, correlator, and post detection combiner. GSM mobile phone can use the proposed algorithm for detection of the Broadcasting Channel, and to obtain the initial timing estimate. The proposed algorithm has a architecture which is suitable for DSP or ASIC implementation, and required memory size is small. The performance of the algorithm is a function of the processing data window size and the threshold values. Proper window size and the threshold values can be determined by analyzing the correlator and combiner. The proposed algorithm has been implemented using DSP, and the performance was verified using baseband simulation. The simulation assumed frequency offset values of 0ppm and 15ppm with the receiver filter bandwidth set at both minimum and maximum. It is shown that the algorithm is robust under various assumptions, and suitable for real implementations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.750-757
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• 2017

Recently, mobile internet traffic has rapidly increased as the huge increase of the smart phone and mobile devices. D2D get attention, because D2D is known that it reduce the traffic load of the base station and also improves the reliability of the network performance. However, D2D has a problem that the efficiency decreases as interference is increased. In this paper, we propose a resource allocation scheme to use the resources efficiently when the D2D link share the cellular resources in the cellular network based the uplink. D2D communication utilizes the location information for allocating resources when the eNB know the location of all devices. The proposed scheme select some cellular user using location informations in order to ensure performance of the D2D communication. and D2D link choose cellular user that performs resource allocation using only selected cellular user. Simulation results show optimal value of resource selection in order to ensure most performance of the D2D communication.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.167-174
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• 2005

With the progress of portable appliances such as cell phone and handhold PC, the popularization of Personal Area Network (PAN) and the diversification of services that are based on Personal Mobile Gateway (PMG) . To use home services at any time regardless of their Position, it needs a virtual home network that a home network and outside networks are finally integrated. Although interoperability among home appliances reached their service stage, research for services and middleware for new small scale network such as PAN is at an early stage. Traditional home network service/connection methods, terminal control schemes, and middlewares must be extended to accommodate PMG-based PAM. In this paper, we propose an integrated virtual home network Platform that guarantees seamless connections between home network and PAM. We also analyze indispensable functions and presents functions that should be added existent home gateway or home sewer by function.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.3
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• pp.230-245
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• 2005

In this paper, we develop a gesture-based input device equipped with accelerometers and gyroscopes. The sensors measure the inertial measurements, i.e., accelerations and angular velocities produced by the movement of the system when a user is inputting gestures on a plane surface or in a 3D space. The gyroscope measurements are integrated to give orientation of the device and consequently used to compensate the accelerations. The compensated accelerations are doubly integrated to yield the position of the device. With this approach, a user's gesture input trajectories can be recovered without any external sensors. Three versions of motion tracking algorithms are provided to cope with wide spectrum of applications. Then, a Bayesian network based recognition system processes the recovered trajectories to identify the gesture class. Experimental results convincingly show the feasibility and effectiveness of the proposed gesture input device. In order to show practical use of the proposed input method, we implemented a prototype system, which is a gesture-based remote controller (Magic Wand).