• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.171-179
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• 2011

In these days, various wireless internet services are possible since the advanced wireless networks enable to transfer more data than before and smarter devices have developed to display the multimedia information more efficiently. Therefore, Korean MIPS such as SKT and LGT provide many kinds of advanced services such as wireless on-line shopping, mobile banking system and etc using 2.5 generation wireless network technology and smartcards. In a transportation system, a cellular phone can be used as a useful payment tool since most people always keep it and a mobile payment system has developed as infrastructure for wireless on-line services. In this paper, a mobile transportation payment system is introduced. A driver needs to pay a toll fee when he/she uses the highways. Recently, a high pass system has introduced, in which a vehicle can pass a toll gate without stopping to pay the fee to a counter. The payment is done automatically by an attached payment device. We have developed an advanced mobile system in which a smartcard embedded cellular phone is used as a payment device. The personnel and financial information is stored at a smartcard and the communication between the phone and OBU(On Board Unit) is done by Bluetooth.

• Analytical Science and Technology
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• v.23 no.1
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• pp.1-14
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• 2010

It is of importance that all countries in worldwide, including EU and China, have adopted the Restrictions on the use of certain Hazardous Substances (RoHS) for all electronics. IEC62321 document, which was published by the International Electronics Committee (IEC) can have conflicts with the standards in the market. On the contrary Publicly Accessible Specification (PAS) for sampling published by IEC TC111 can be adopted for complementary application. In this work, we tried to find a route to disassemble and disjoint cellular phone sample, based on PAS and compare the screening methods available in the market. For this work, the cellular phone produced in 2001, before the regulation was born, was chosen for better detection. Although X-ray Fluorescence (XRF) showed excellent performance for screening, fast and easy handling, it can give information on the surface, not the bulk, and have some limitations due to significant matrix interference and lack of variety of standards for quantification. It means that screening with XRF sometimes requires supplementary tool. There are several techniques available in the market of analytical instruments. Laser ablation (LA) ICP-MS, energy dispersive (ED) XRF and scanning electron microscope (SEM)-energy dispersive X-ray (EDX) were demonstrated for screening a cellular phone. For quantitative determination, graphite furnace atomic absorption spectrometry (GF-AAS) was employed. Experimental results for Pb in a battery showed large difference in analytical results in between XRF and GF-AAS, i.e., 0.92% and 5.67%, respectively. In addition, the standard deviation of XRF was extremely large in the range of 23-168%, compared with that in the range of 1.9-92.3% for LA-ICP-MS. In conclusion, GF-AAS was required for quantitative analysis although EDX was used for screening. In this work, it was proved that LA-ICP-MS can be used as a screening method for fast analysis to determine hazardous elements in electrical products.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.4
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• pp.505-509
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• 2011

Home network system makes it available for controlling inside home and for controlling from outside as well with personal computer, cellular phone or smart phone, by connecting diverse information equipments within home such as lighting, gas, and heating equipments with network. Integrated server and wall-pad, which form home network system, have demerits as saying of being high-priced and of needing to implement network infrastructure. This study suggested the intelligent home network system, which uses smart phone of supplementing these merits of home network system. It substituted high-specification input & output equipment in the currently and widely supplied smart phone for display and touch screen, which are user interface part of the existing wall-pad, and implemented the common wall-pad with low cost by concentrating management and control function of home network on smart phone.

• Child Health Nursing Research
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• v.19 no.4
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• pp.270-281
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• 2013

Purpose: This study was done to develop a prevention program for media addiction in elementary school students, and to examine its effects on television addiction, internet addiction, cellular phone addiction, and impulsiveness. Methods: The study was designed using a nonequivalent control group pretest-posttest design. The participants were 58 elementary school students (29 in the experimental group and 29 in the control group). Students in the experimental group were given the prevention program for media addiction. The data were analyzed using the SPSS/WIN 19.0 program. Results: Students in the experimental group reported a significant decrease in television addiction compared to students in the control group. Conclusion: The results of the study indicate that the prevention program for media addiction was effective in decreasing television addiction in elementary school students.

• The Korean Journal of Applied Statistics
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• v.17 no.2
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• pp.205-218
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• 2004

Conjoint analysis is employed to decompose the consumer's preference judgements into the importance of attributes, and to predict the degree of preference for each profile of the products, services, or ideas. It has been widely used in industrial marketing, particularly in the areas of product positioning and new product development. This paper is mainly concerned with the conjoint analysis based on the Chebyshev estimation since the efficiency of the least squares estimator is lower than that of the Chebyshev estimator when the preferences are measured as the rank-order. A case study is performed on the preference for cellular phones. And it is shown that conjoint analysis based on the Chebyshev estimation is superior, in terms of the predictive validity, to one which is based on the least squares estimation.

• Journal of the Korean Society of Safety
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• v.19 no.3 s.67
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• pp.32-39
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• 2004

This papers describes on the experimental consideration for the intrinsically-safe explosion-proof capability of rechargeable battery's body about main item rechargeable battery and cellular phone battery which is selling in domestic that IEC(International Electrotechnical Commission) recommend the measurement of ignition limit by short circuit of rechargeable battery and temperature increase test to use a explosion grade Group IIC type of explosion-proof type apparatus test an object of hydrogen gas. Because of that there are many different results for existence or nonexistence for ignition by different company and different types. It is concluded that the maximum of self temperature increasing by spark circuit of rechargeable battery is $180^{\circ}C$ in case of Nickel-Hydrogen and $110^{\circ}C$ in case of Nickel-Cadmium. The reaction of cellular battery for external temperature have following processes. It is confirmed that the temperature of reaction is rise slantly as the ambient temperature rising, then exterior shape of one is swell up and change when the temperature of ambient reach to about $130\~140^{\circ}C$, and when reach to about $160^{\circ}C$ the battery is blown up. Therefore, it is considered that have to be in considering selection of rechargeable battery using in itself due to different ignition limits of various rechargeable battery when the portable electric containing rechargeable battery are designed, produced and used, the characteristics and the proper safety factors of devices.

• Journal of Internet Computing and Services
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• v.18 no.5
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• pp.17-22
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• 2017

In a MPC coding using excitation source of voiced and unvoiced, it would be a distortion of speech waveform. This is caused by normalization of synthesis speech waveform of voiced in the process of restoration the multi-pulses of representation section. This paper present PCFBD-MPC( Position Compensation Frequency Band Division-Multi Pulse Coding ) used V/UV/S( Voiced / Unvoiced / Silence ) switching, position compensation in a multi-pulses each pitch interval and Unvoiced approximate-synthesis by using specific frequency in order to reduce distortion of synthesis waveform. Also, I was implemented that the PCFBD-MPC( Position Compensation Frequency Band Division-Multi Pulse Coding ) system and evaluate the SNRseg of PCFBD-MPC in coding condition of 8kbps. As a result, SNRseg of PCFBD-MPC was 13.4dB for female voice and 13.8dB for male voice respectively. In the future, I will study the evaluation of the sound quality of 8kbps speech coding method that simultaneously compensation the amplitude and position of multi-pulse source. These methods are expected to be applied to a method of speech coding using sound source in a low bit rate such as a cellular phone or a smart phone.

• Journal of Internet Computing and Services
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• v.19 no.6
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• pp.1-7
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• 2018

This paper present an 8kbps ACLMS-MPC(Amplitude Compensation and Least Mean Square - Multi Pulse Coding) coding method integrated with ACFBD-MPC(Amplitude Compensation Frequency Band Division - Multi Pulse Coding) and LMS-MPC(Least Mean Square - Multi Pulse Coding) used V/UV/S(Voiced / Unvoiced / Silence) switching, compensation in a multi-pulses each pitch interval and Unvoiced approximate-synthesis by using specific frequency in order to reduce distortion of synthesis waveform. In integrating several methods, it is important to adjust the bit rate of voiced and unvoiced sound source to 8kbps while reducing the distortion of the speech waveform. In adjusting the bit rate of voiced and unvoiced sound source to 8 kbps, the speech waveform can be synthesized efficiently by restoring the individual pitch intervals using multi pulse in the representative interval. I was implemented that the ACLMS-MPC method and evaluate the SNR of APC-LMS in coding condition in 8kbps. As a result, SNR of ACLMS-MPC was 15.0dB for female voice and 14.3dB for male voice respectively. Therefore, I found that ACLMS-MPC was improved by 0.3dB~1.8dB for male voice and 0.3dB~1.6dB for female voice compared to existing MPC, ACFBD-MPC and LMS-MPC. These methods are expected to be applied to a method of speech coding using sound source in a low bit rate such as a cellular phone or internet phone. In the future, I will study the evaluation of the sound quality of 6.9kbps speech coding method that simultaneously compensation the amplitude and position of multi-pulse source.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.702-708
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• 2002

In this paper, we design the dual frequency antenna that could easily determine two operation frequencies by its inverted-F antenna structure and spur line length. The spur line is applied to the inverted-F antenna, in order to dual operation characteristics in PCS and cellular frequencies. It has designed by using the IE3D commercial software based on the moment method. As the designed antenna is fabricated and measured, you can see the results such as the return loss, the input impedance, the radiation patterns, and the gain. The size of this antenna is 40 mm$\times$14 mm$\times$9.4 mm, it is compact enough to use as an intenna. Also, This antenna can be used with cellular and PCS phone of domestic market.

• Biomedical Science Letters
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• v.14 no.4
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• pp.257-261
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• 2008

Cellular phones are the most used electronic device everyday in modern life and are always in contact with our hands, Although many studies have revealed microorganisms living on our hands, there are only a few reports on the research about products or places which are in contact with our hands. Therefore, the purpose of this study is to verify microorganisms living in cellular phones. Microorganisms were scraped from cellular phones of students and professors from the clinical laboratory science department in Daegu Health College, and cultured at Brain Heart Infusion agar and MacConkey agar following API kit to identify them. The average colony number was $1.5{\times}10^2$ on BHI agar and $40{\times}10$ on MacConkey agar. There was no difference according to gender. In Gram stain result, Gram(+) Cocci showed the highest frequency. Also in BHI agar plates, Micrococcus spp and Acinetobacter baumannii identified with high frequency. Moreover, S. aureus, which is very well known as strong food poisoning bacteria, was isolated. Klebsiella pneumonia ssp pneumonia was isolated with the highest frequency from the MacConkey agar or S-S agar plate. From these results show, there are as many different microorganisms from cellular phones as from our hands. This is the first report isolating strong food poisoning bacteria in cellular phones. Since infection in hospitals have been an important issue to be aware of, it is equally necessary to investigate cell phones and products which hospital workers touch with their hands.