• Journal of the Institute of Electronics Engineers of Korea TC
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• 제42권3호
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• pp.19-24
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• 2005

This paper presents design simulation, implementation, and measurement of a miniaturized GPS/K-PCS dual-band LTCC chip antenna for mobile communication handsets. The dimension of LTCC chip antenna is $9mm\times15mm\times1.2mm$. The meander type radiating patch for dual-band operation is realized by using via holes with 0.3mm height to connect upper and lower-layer antenna. The lower meander type antenna is to be tuned to the lower frequency (GPS) band. The upper meander antenna with via hole connection is to contribute the higher frequency (K-PCS) band. The resonant frequency and frequency ratio of the proposed antenna can be adjusted by changing the height of via-hole and effective path of meander radiating patch. The electrical characteristics of the meander chip antenna applied to a GPS/K-PCS are suitable for mobile communication application.

• Journal of IKEEE
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• 제7권1호
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• pp.88-96
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• 2003

In this paper, We designed and implemented a linear high-power amplifier which can be used for the commercial service in band of $1.9GHz(1.93{\sim}1.99GHz)$ at U.S.A. The output power of the implemented linear high power amplifier is 25W. In order to satisfy IMD characters decided by FCC, the Feedforward linearization techniques has been used. The used feedforward method has improved the IMD characteristics from 10.51dBc to 19.01dBc in each power level from 1W(30dBm) to 25W(44dBm). The IMD level of the final output shows from minimum 64.84dBc to maximum 68.17dBc. Because this good characteristics of IMD, the LPA is expected to use as a commercial product of PCS base station.

• Journal of Advanced Navigation Technology
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• 제15권2호
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• pp.197-203
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• 2011

A triple-band antenna which can be used at GSM900, PCS1900 and Bluetooth(or Wi-Fi) frequency band is proposed. The proposed antenna is designed based upon switching between IFA(Inverted F Antenna) that has a resonant length of ${\lambda}/4$ and loop antenna that has a resonant length of ${\lambda}/2$. It can be applied to triple-band only by use of single printed pattern due to the switching characteristic. It is designed by use of the IFA for the application to the GSM900, while it is designed by use of the loop antenna for the application to the PCS1900 and by use of additional pattern of IFA for the application to the Bluetooth(or Wi-Fi) respectively. As a result, it has been observed that the proposed antenna satisfies the required return loss(${\leq}10dB$) and also has efficiency(${\geq}80%$) over the whole band. Moreover the proposed antenna has omni-directional radiation pattern which is suitable to apply to the mobile phone.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제10권5호
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• pp.792-797
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• 2006

In this paper, an internal integrated microstrop patch for PCS handset is designed. To increase the bandwidth of microstrip patch antenna, a configuration of stacked type using parasitic element is used. Furthermore, to reduce the size of microstirip patch antenna, the main radiator in the substrate is shorted to the ground plane using five shorting-posts while three parasitic elements on the superstrate are also shorted to the ground plane using two shorting-posts respectively. The antenna bandwidth and radiation characteristics are calculated by HFSS 7.0 software, and compared with the experimental results. Experimental results show that the return loss is less than -10dB over the band of 1766MHz to 1900 MHz(134MHz) and the size of the fabricated microstrip patch antenna are $23\times20\times6.35mm$.

• Journal of KIISE:Computing Practices and Letters
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• 제6권2호
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• pp.206-215
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• 2000

This paper is concerned with the development of PCS(Platform for Collaborative System), which is a platform for development of remote collaborative experiment systems. Platform does not aim at the development of special-domain applications. This system implies the common development environments which can develop all-domain applications. PCS consists of collaborative experimental objects such as communication, session, user, application, media, message object and management objects that have management functions. Management objects are made up of collaborative experimental objects and operations which manipulate control information and data. It also supports application sharing for making single user interface of experimental applications to multi-user interface. Application sharing also supports instruments control on the remote site. PCS platform supports total environments for remote collaborative experiment and can be used as infrastructure to all kinds of collaboratory systems.

• Journal of Society of Preventive Korean Medicine
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• 제21권2호
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• pp.35-44
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• 2017

Objectives : The purpose of this study was to investigate the association between quality of life and Mibyeong index of abnormal symptoms by the Mibyeong state. Methods : A total of 1,100 people were recruited into this study and were collected by specialized research company. The data were collected by personal information using MBI(Mibyeong Index) and SF-12 (Short form-12) and were analyzed with SPSS (version 21.0) computer program, and included Pearson's chi-square test, ANOVA, Pearson's correlation coefficient, and multiple regression analysis. Results : The Mibyeong Index which represents abnormal symptom type showed significant difference for Mibyeong state (p<.001). In Total subject, fatigue, pain, low sleep quality and indigestion were found to be significant predictors of PCS(Physical Component Summary). In Healthy group, pain was found to be significant predictor of PCS. In MI 1 group, fatigue, pain, indigestion and anxiety were found to be significant predictors of PCS. In MI 2 group, fatigue, pain and low sleep quality were found to be significant predictors of PCS. In Total subject, fatigue, depression, anger and anxiety were found to be significant predictors of MCS (Mental Component Summary). In Healthy group, indigestion and anxiety were found to be significant predictors of MCS. In MI 1 group, depression and anger were found to be significant predictors of MCS. In MI 2 group, fatigue and depression were found to be significant predictors of MCS. Conclusions : The relationship between Quality of life and MBI changes according to Mibyeong state. We expect that this result could be contribute to health management of people in Mibyeong state.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제23권6호
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• pp.1602-1609
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• 1998

In this paper, the design and implementation of the novel RF front end circuit for CDMA based PCS phone is described. This novel scheme is realized by building the power amplifier module combined with duplexer. The dielectric filters which are parts of duplexer are broken up and relocated into the module. Electromagnetic analysis for via holes and coupling between narrow transmissio lines is icluded to design a circuit. The combined moule has been minimaturized to be as small as 1.5CC. It has satisfied IS-95 requirements for linearity performances of CDMA signal at 24-dBm output power as well as played apart as a duplexer. The operating current of about 95mA has been saved owing to both rearranging dielectric filters and limiting operating point to class-B by considering real working power range of CDMA phones.

• Journal of the Korean Society of Safety
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• 제33권4호
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• pp.1-7
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• 2018

This paper is analyzed for the thermal characteristics(1 year) of the 6 components(DC breaker, DC filter(including capacitor and discharge resistance), IGBT(Insulated gate bipolar mode transistor), AC filter, AC breaker, etc.) of a photovoltaic power generation-based PCS(Power conditioning system) below 20 kW. Among the modules, the discharge resistance included in the DC filter indicated the highest heat at $125^{\circ}C$, and such heat resulting from the discharge resistance had an influence on the IGBT installed on the rear side the board. Therefore, risk priority through risk priority number(RPN) of FMEA(Failure modes and effects analysis) sheet is conducted for classification into top 10 %. According to thermal characteristics and FMEA, it is necessary to pay attention to not only the in-house defects found in the IGBT, but also the conductive heat caused by the discharge resistance. Since it is possible that animal, dust and others can be accumulated within the PCS, it is possible that the heat resulting from the discharge resistance may cause fire. Accordingly, there are two options that can be used: installing a heat sink while designing the discharge resistance, and designing the discharge resistance in a structure capable of avoiding heat conduction through setting a separation distance between discharge resistance and IGBT. This data can be used as the data for conducting a comparative analysis of abnormal signals in the process of developing a safety device for solar electricity-based photovoltaic power generation systems, as the data for examining the fire accidents caused by each module, and as the field data for setting component management priorities.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제18권5호
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• pp.503-510
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• 2007

This paper proposes the design scheme of internal triple band antenna intended for using in GSM900, DCS1800, and PCS1900 bands. The suggested folding metal plates of the two branches are mounted on a dielectric coated ground plane for size miniaturization and durability. Return losses are overlapped when length of metal branches are controlled. This is important technique for wide band operation. For the suggested antenna geometry its return loss was calculated by HFSS 9 simulator, and was shown to be -10 [dB] less within the required band. Also, gain and radiation pattern of antenna were measured using far field measurement system in an anechoic chamber. The measured peak gain is more than 3.0 [dBi], and the average gain is over -1.0 [dBi] for the triple band, which is regarded as satisfactory for the internal antenna application. Also, the radiation pattern for two frequencies shows a similar shape each other within the required band.

• The Transactions of the Korean Institute of Power Electronics
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• 제16권4호
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• pp.405-414
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• 2011

Recently, the development of several hundreds of kW scale PCS for fuel cell generation is required as commercialization process of distributed generation systems using high temperature fuel cells such as MCFC begins. This paper proposes and optimized topology suitable for MCFC fuel cell generation system and LCL filter design method considering voltage quality of local loads such as MBOP. An interleaving technique is applied to step-up DC-DC converter, optimized number of phases is determined considering efficiency and volume. Also, a LCL filter design method is proposed considering quality of current injected to the grid as well as that of voltage across the local load. The proposed PCS system is validated through reduced 1kW prototype.