• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1541-1547
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• 2005

In this paper, Dualband internal antenna for GSM/DSC handset is proposed. The antenna has a size of about $38mm{\times}90mm{\times}1mm$, giving a total mobile phone PCB for support and fold type patch of about $30mm{\times}8mm{\times}3.2mm$. This antenna characteriatic facilitates the fine-tuning of the two operating frequencies of 909MHz and 1762MHz in the dualband design. The measured radiation pattern in the E-plane and H-plane for operating frequencies of 909MHz and 1762MHz is compared and analyzed. The designed and fabricated two band internal antenna for GSM/DSC handset have a gain between 0dBi and 2.0dBi at all bands. Also, the electric firld distribution and directivity on human head caused by portable phone is analyzed. An analysis model is composed of a human head model and the antenna mounted on the same ground plane as portable telephone size.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.8
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• pp.1893-1900
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• 2015

The government has the responsibility to prevent abuses of monopoly and promote competition in order to maximize consumer welfare. The government should address the asymmetry in the information as much as possible and ensure consumer choice. The subsidy seems to reduce the burden on the consumer service charges and handset prices but it actually distorts the market through price discrimination. The government caused the principal-agent problem by neglecting their appropriate role to prevent distortion of the mobile telecom market. The money used as subsidy is part of excess profit and could be transferred to down the price of mobile phone and charges and it would become a benefit to consumers. Separate announcement of subsidies by Mobile Communications Terminal Distribution Structure Improvement Act is a little developed policy but it was not actually realized. The market price close to that from perfect competition structure is plausible, ultimately.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.141-148
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• 2012

Android that was made by Google and Open Handset Alliance is the open source software toolkit for mobile phone. Nowadays, Smart phone users have been rapidly increasing, by that reason a lot of application contents have been released and especially contents which focus on user convenience have been developed. In this paper, we develop a new application content smart alarm based on Google Android flatform. The features of the developed content are as follows. First, users set their day's schedules. So they can notify easily what they have to do at the moment. Second, when users set their alarms not to forget several sequential tasks, they can set their schedules by not only alarm method but also timer method. In the performance evaluation, we show the results of simulation using AVD(Android Virture Device).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.706-713
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• 2010

In this paper, the small loop antenna with a parasitic loop structure for penta-band mobile phone application is proposed. This antenna is composed of a feed monopole, a radiating loop antenna with a parasitic loop structure and an additional radiating element. The antenna is printed on the very thin flexible substrate to mount on the dielectric carrier with a volume of 40 mm$\times$11 mm$\times$3 mm. The bandwidth of the proposed antenna is 402 MHz(773~1,175 MHz) for low band and 583 MHz(1,622~2,205 MHz) for high band. As a result, the proposed antenna covers the five bands of GSM850, GSM900, DCS1800, PCS1,900 and WCDMA for a 3:1 VSWR. Moreover, the radiation pattern, gain and efficiency are appropriate for mobile handset. Therefore, this antenna is suitable for small sized multi-band mobile handset applications.

• Journal of Information Technology Services
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• v.9 no.3
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• pp.25-43
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• 2010

The speed and magnitude of mobile phone adoption is a recent worldwide phenomenon akin to those of the television in the middle of the 20th century and the Internet in the late 20th century. During the 2000s, mobile phone adoption was exploded and subscriptions reached 3 billion around the globe. Korea and Japan have been ahead of the rest of the world in introducing new handset and service capabilities. They were the first markets to launch 3G services and are currently the only markets to have achieved mainstream adoption of 3G with over one-third of customers in both markets subscribing to 3G services. The purpose of this article is to explore the cultural similarities and differences associated with mobile mail by presenting findings from a cross-cultural comparison of perceptions and uses of the technology. The results of the study are as follows：Of the characteristics that make up the mobile text-messaging service in Korea, a person's perceived ease of use and perceived enjoyment was found to have a positive effect on use attitude. Among the characteristics that make up a person's perceived ease of use, perceived enjoyment was found to have a positive effect on use intention. And use attitude was found to have positive effects on use intention. But, of the characteristics that make up the mobile text-messaging service in Japan, a person's perceived usefulness, perceived ease of use and perceived enjoyment were found to have a positive effect on use attitude. Among the characteristics that make up a person's perceived usefulness, perceived ease of use and perceived enjoyment were found to have a positive effect on use intention. And use attitude was found to have positive effects on use intention. This study contributes to telecommunications research by delineating the various stimuli to consider for successful technology acceptance in a global setting, which can account for differential impacts across regions. The findings of this study can assist telecommunications operators in formulating an effective region-specific strategy when launching a wireless data service in a particular environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1095-1103
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• 1999

Presently, the retractable phone with a whip antenna composed of a helix and a monopole is most widely used for cellular mobile communications. However, since the length of the monopole is usually about λ/4, the strong radiated electric fields are produced in the region where the auricle of a head is contacted directly. This field distribution results in high specific absorption rates(SAR's) in the head. In this paper, SAR distributions and local SAR values for the inversely shaped phone(ISP) whose antenna arrangement is opposite to the original retractable phone(ORP) are compared with those for the ORP. This phone is accomplished by mounting the $\lambda$/4-whip antenna on the bottom, not on the top of the handset. The time-averaged field distribution in a computational space including a human model and a phone model is computed using the finite-difference time-domain(FDTD) method. SAR distributions and local SAR values for these phones are calculated with the field distributions. An anatomical head model and an approximate hand model were used to consider a real situation. From the analyzed data, it is shown that this arrangement of the antenna considerably reduces the spatial peak SAR in a human head.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.4 s.334
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• pp.29-36
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• 2005

Many novel designs of planar antennas for related applications such as internal mobile phone antennas, base station antennas, WLAN or Bluetooth antennas, and so on, have been reported very recently, especially since the year 2000. In this thesis, Dualband internal antenna for GSM/DSC handset is proposed. The antenna has a size of about 38mm$\times$90mm$\times$1mm, giving a total mobile phone PCB for support and fold type Patch of about 30mm$\times$8mm$\times$3.2mm. This antenna characteristic facilitates the fine-tuning of the two operating frequencies of 909MHz and 1762MHz in this dualband design. The measured radiation pattern in the E-plane and H-plane for operating frequencies of 909MHz and 1762MHz is compared and analyzed. The designed and fabricated two band internal antenna for GSM/DSC handset have a gain between 0dBi and 2.0dBi at all bands.

• Journal of Information Processing Systems
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• v.10 no.1
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• pp.92-102
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• 2014

In recent years, there has been growing interest in secure pairing, which refers to the establishment of a secure communication channel between two mobile devices. There are a number of descriptions of the various types of out-of-band (OOB) channels, through which authentication data can be transferred under a user's control and involvement. However, none have become widely used due to their lack of adaptability to the variety of mobile devices. In this paper, we introduce a new OOB channel, which uses accelerometer-based gesture input. The gesture-based OOB channel is suitable for all kinds of mobile devices, including input/output constraint devices, as the accelerometer is small and incurs only a small computational overhead. We implemented and evaluated the channel using an Apple iPhone handset. The results demonstrate that the channel is viable with completion times and error rates that are comparable with other OOB channels.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1455-1461
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• 2008

We implemented a subminiature internal antenna that is around 1 cc volume for the mobile phone. The fundamental type of studied antenna is IFA(Inverted F Antenna), and this antenna is designed to be improved efficiency and gain due to minimum current cancellation by the avoidance of multiple bending pattern. For the implementation of multiple band, helix is applied to compensate for short antenna length for low frequency band, and a 3 dimensional pattern is used for high frequency band. We made two kinds of 3D structure antenna. One is a 1 cc volume antenna for GSM/DCS band on the bare board set, and the other is a 1.5 cc volume for the GSM/USPCS mobile phone set. Measurements showed good gain performance that average gain of two antenna on each band are $-3.46{\sim}-0.45\;dBi$ and $-4.80{\sim}-3.29\;dBi$ respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.3
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• pp.315-320
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• 2010

In this paper, an internal TDMB(Terrestrial Digital Multimedia Broadcasting) antenna for mobile phone is proposed. The overall dimension of designed antenna with substrate is 30 mm$\times$5 mm$\times$0.6 mm. The proposed antenna consists of a meander type radiator which is connected front- and back-plane of Kapton substrate by via hole and parasitic element for tuning the resonant frequency. And to compensate the electric length of desired frequency, passive inductor is used for matching element. Measured gain of the implemented antenna -17.6 dBi at 174 MHz, -13.01 dBi at 195 MHz, and -14.9 dBi at 216 MHz.