• Journal of Korean Society of Transportation
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• v.34 no.3
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• pp.222-233
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• 2016

Recently, mobile phone data was applied in travel demand modeling as a new source of dynamic population movement. This study is also aimed to estimate "occupancy population" during a given period of time within a given spatial region using mobile phone data. An occupancy population was defined as the number of people residing or moving within a given time and space. In case of Seoul Metropolitan area, we divided the area into a number of administrative districts as zones for analysis and estimated the occupancy population of each zone by mobile phone data collected by SK telecom Co., a wireless telecommunication provider in Korea. For the expansion of mobile phone data, a new concept of "communication probability" was introduced and applied in the estimation of occupancy population of each zone by the hour. We compared the estimated number with the daytime population and the daytime population index referred by the Statistics Korea. The results showed that a positive correlation existed between the estimated number and the statistical number by nationwide survey. It was concluded that mobile phone data could be more cost-effective sources than a conventional survey method to estimate the pattern of population movement by the hour or by the day.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8C
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• pp.741-749
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• 2012

Since introduction of smart phone in Korean mobile telecommunication market, mobile internet service market has changed dramatically. Although there have been many heated discussion of pro and cons of recent tremendous growth of mobile traffic, mobile data service market has contributed to re-development of whole telecommunication market. This paper is aimed at empirically test and confirms the occurrence of induced demand resulted from LTE service launching. In conclusion, we suggest the direction of regulation and policy for sustainable development of mobile internet service.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.10
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• pp.1017-1026
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• 2013

Four countries are participating in exposure assessment for Mobi-Kids Study. Each country evaluates RF and ELF exposure from mobile phones considering telecommunication system and environment in the corresponding area. The results will be used to determine accumulation exposure level of each subject in case and control groups to assess the potential carcinogenic effects of childhood and adolescent exposure to radio frequency(RF) and extremely low frequency( ELF) from mobile phones on the central nervous system. This paper analyzes exposure types of mobile phones which have been used in Korea for about 10 years, based on Mobi-Kids protocol. It includes investigation of mobile phone models released in the domestic market, design of numerical phone models to represent each exposure type, and measurement of ELF radiation from mobile phones.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.72-78
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• 2007

In this paper, the wide-band monopole antenna with a parasitic element on the ground plane for application in Cellular, GSM and RFID mobile terminals such as the mobile phone or Personal Digital Assistant(PDA) phone is presented. The VSWR of the designed antenna is 2:1 over the frequency range of 820 MHz to 1040 MHz(bandwidth of 23.6 %). Therefore, the designed antenna can provide wide bandwidth covering the Cellular(824 MHz~894 MHz), RFID(908.5 MHz~914 MHz) and GSM(Tx:880 MHz~915 MHz, Rx:925 MHz~960 MHz). The radiation characteristics of the fabricated antenna were also studied. According to the measured radiation patterns, the maximum gains at 859 MHz and 911.25 MHz(center frequencies of the Cellualr and RFID bands) are -0.7 dBi and 0.16 dBi, respectively. The measured maximum gains of GSM bands are -0.48 dBi(897.5 MHz, the center frequency of Tx) and 1.69 dBi(942.5 MHz, the center frequency of Rx).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.2
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• pp.149-155
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• 2014

In this paper, we study the complex mobile antenna for WPT(Wireless Power Transfer) with NFC(Near Field Communication) of inductive coupling using FPCB which has half thickness compared with the existing coil type antennas. Considering the pattern thickness of loop antenna, the analysis of electromagnetic wave absorber and battery's influence, absorber thickness, the ranges of design parameters are obtained. The proposed antenna has 0.45 mm thickness using single layer 3 oz FPCB and absorber. From measurement, the characteristics of NFC antenna can be satisfied with the specifications of EMVCo. and domestic mobile telecommunication and the transmission efficiency of the proposed WPT antenna is 68.1 % which is competitive with the existing coil type antenna. From the results of this paper, it has been confirmed that the proposed antenna can be used as the WPT and NFC antenna for mobile phone. Key words: Wireless Power Transfer, Near Field Communication, Mobile Phone Antenna, Absorber, FPCB.

• International Journal of Safety
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• v.1 no.1
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• pp.43-46
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• 2002

In this study, we adopt the strength variation (equation omitted) of electromagnetic waves by their distance. The location of antenna emitting electromagnetic waves is moved to its opposite side and the distance between human body and antenna is secured more. Therefore, the cellular phone designed in this study can reduce the impact of electromagnetic waves absorbed in local part of human body (in particular, head) and then can have competitiveness in the world market facing the regulations.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.1101-1110
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• 2004

In the first quarter of 2004, there were about 1 billion 348 million mobile phone users worldwide with a penetration rate of only 29%. Korea ranks among the highest in the use of mobile communication, having over 36 million mobile phone subscribers with a mobile phone penetration rate of 75% as of May 2004. Since the introduction of wireless Internet service in May 1999, the number of subscribers rose to 34.5 million with 95.3% of the total mobile phone subscribers using wireless Internet services in May 2004, largely due to continued investments by telecommunication service providers, improvement of mobile handsets (color and digital camera phones) and implementation of policies on mobile number portability. In the Korean wireless Internet market, there are many user complaints since the service providers are competing with each other through TV commercial sales and phone discounts rather than improving their call quality, services and billing systems. therefore there is a growing need to improve the billing systems through means such as the implementation of reasonable payment plans according to consumer use, development of a wireless Internet billing system that can predict the number of users and establishment of pricing standards for controlled data (head, tail, etc...) as well as menu information by testing the texts. multimedia, video and other types of content provided by the three major mobile communication companies. The purpose of this study is to promote wireless Internet services and protect user rights by proposing a reasonable way to improve the billing systems for wireless Internet services after conducting a comparative analysis of file size and billing data of each of the service providers through a verification test on a packet billing system for wireless Internet services.

• The Journal of Engineering Research
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• v.8 no.1
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• pp.87-95
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• 2006

Present time, the mobile telecommunication companies of our country are still using independence wireless internet platform. So, this carry many difficulties to the phone company and content provider company. Because even they develop one product and they must make it prepare for some platform of every mobile telecommunication companies. And this make the development more longer and more expensive. For this reason, SKT, LG telecom and KTF develop the new wireless internet platform named WIPI with ETRI. and the working is still go on and go ahead with propulsion. And if it come to reality, the WIPI will attached from much of attack such as hacking or virus. But some data exchange between mobile phone is so important as to flow. Thus, in this paper, we are design and implementation the data encryption system working at the WIPI in order to protect the data, we want to protect.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.9
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• pp.1694-1701
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• 2007

Recently The biggest three mobile telecommunication companies of our country still using independence wireless internet platform. And, It can so many difficulties to the phone company and content provide company. Such as the timing of the development or the fee of the development. Because even they develop one product and Hey must make it prepare for some platform of every mobile telecommunication companies. And this make the development more longer and more expensive. For this reason, SKT, LG telecom and KTF develop the new wireless internet platform named WIPI with ETRI. and the working is still go on and go ahead with propulsion. And if it come to reality, the WIPI will attached from much of attack such as hacking or virus. But some data exchange between mobile phone is so important as to flow. Thus, in this paper, we consideration the XML using in the wireless environment and we are design and implementation the XML encryption system working at the WIPI in order to protect the data, we want to protect.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.931-933
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• 2010

There are various types of educational contents in mobile world. Moreover new and various kinds of contents have been developed recently according the smart phone has become popular. Therefore, many telecommunication companies of domestic and overseas are showing many kinds of smart phone as to customers are growing more and more interested in mobile devices. Currently, most of the language educational contents are composed to foreign languages like English, Japanese, Chinese, but the development of Korean educational contents are inadequate. In this paper, so, we design the linguistic contents for beginning Koran education of foreigner which are used on mobile platforms.