• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1A
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• pp.31-36
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• 2004

In this paper, we proposed the new structure of the Rake Finger using Walsh Switch, the shared accumulator, and the pipeline-FWHT algorithm for reducing the signal processing complexity resulting from the increase of the number of data correlator. The function simulation of the proposed architecture is performed by Synopsys tool and the timing simulation is performed by Compass tool. The number of computational operation in the proposed data correlators is 160 additions and the conventional ones is 512 additions when the number of walsh code N=4. As a result, it is reduced about 3.2 times other than the number of computational operation of the conventional ones. Also, the result shows that the data processing time of the proposed Rake Finger architecture is 90,496[ns] and the conventional ones is 110,696[ns]. It is $18.3\%$ faster than the data processing time of the conventional Rake Finger architecture.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.99-107
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• 1996

When GPS (global positioning system) is used as synchronous signal in CDMA digital cellular base station system and high speed digital synchronous communication network, antenna cable length is increased, comparing with other GPS application such as positioning or car navigation. In this paper, it is proposed that a type of new GPS antenna system including RF stage for reduction of cable loss in case of long cable.The antenna system with TMPA(truncated-corners microstrip patch antenna) is designed and fabricated because GPS signal has RHCP (right-hand circular polarization), consequently antenna size can be made small size. LNA (low noise amplifier) is designed by using HEMT(high electron mobility transistor)which has lower noise figurae and better AGC characteristics at low voltage than GaAs FET, and we equiped mixer, in GPS antenna unit, which converts from 1575.42MHz to 75.42MHz. As result of comparing between typical system and proposed system when cable length is 60m, 63dB, 55dB and 25dB gain are obtained for RG-316/U, RG-58C/U and RG-213/U, and better characteristics are achieved than typical system as far as cable length is longer.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.4
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• pp.405-410
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• 2006

This paper presents the design of a USB home controller and a home control system that specially is focused on controlling home appliances as a part of home network systems, the implementation of the USB device access class in an OSGi service platform and a home security system as an application. Designed USB home controllers are able to control various home appliances. They can be used not only to control big home appliances like a boiler but also to control small home appliances like a toaster because they are low-cost solutions. The USB home controller supports real time control using the interrupt transfer of the USB specification. And It is easy to use by homemakers who have no technical knowledge of the system because they just plug and unplug it in a home server then it automatically joins and leaves a home control system. This technique is based on hot-plug and the USB Device Access class in an OSGi Service Platform. The USB Device Access class supports the coordination of automatic detection and attachment of the USB home controller on an OSGi Service Platform, and it downloads and installs device drivers on demand. For an application, we implemented and tested a home security system using two USB home controllers and a CDMA module.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.66-68
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• 2007

본 논문에서는 CDMA 상향 중심주파수인 836.5MHz에서 단말기 송신 전력 제어를 위한 Schottky 다이오드 전력 검출기 기본 회로 구조를 제안한다 일반적인 다이오드의 비선형성에 의한 검파 출력의 선형성 개선과 낮은 입력 레벨의 출력 전압 감도 특성을 개선하기 위해서 낮은 검출기 입력 레벨에서의 임피던스 매칭을 한다 다이오드 패키지의 기생 성분을 고려한 시뮬레이션을 통하여 비교적 정확한 측정 결과를 예측할 수 있다. 본 논문의 전력 검출기의 전압 감도는 최대 0.1V의 비교적 우수한 특성을 보이며, -20dBm에서 +15dBm의 검출기 입력 대역에서 임피던스 매칭의 분석을 통하여 선형성의 뚜렷한 개선 효과를 얻는다. 또한 입력 주파수의 대역폭에 따른 매칭특성과 개선된 검파 출력 특성도 제시된다.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.73-76
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• 2005

The advanced information and communication technology gives vehicles another role of the third digital space, merging a physical space with a virtual space in a ubiquitous society. In the ubiquitous environment, the vehicle becomes a sensor node, which has a computing and communication capability in the digital space of wired and wireless network. An intelligent vehicle information system with a remote control and diagnosis is one of the future vehicle systems that we can expect in the ubiquitous environment. However, for the intelligent vehicle system, many issues such as vehicle mobility, in-vehicle communication, service platform and network convergence should be resolved. In this paper, an in-vehicle gateway is presented for an intelligent vehicle information system to make an access to heterogeneous networks. It gives an access to the server systems on the internet via CDMA-based hierarchical module architecture. Some experiments was made to find out how long it takes to communicate between a vehicle's intelligent information system and an external server in the various environment. The results show that the average response time amounts to 776ms at fixec place, 707ms at rural area and 910ms at urban area.

• Archives of design research
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• v.15 no.3
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• pp.29-38
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• 2002

Recently, types of mobile services are ever-growing with technological advances, such as CDMA 2000, 256 Color LCD, 16 channel sound chip set and easy internet access. However, manual system that is supposed to support users for finding features and functions doesn't help users most of the cases since users are moving. Therefore, mobile sonics needs new concept for manual system that can support users while they are in use In this research report, new concept for interactive manual system is suggested. Then a guideline for interactive manual system is developed as a result from three empirical studies. First, ten information visualization methods used for describing functions are positioned on user's perception map. Secondly, user behavior pattern of getting required information from written manual was analyzed. Finally, visual cue system was selected as one of options for developing interactive manual system and a guideline was developed based on these research results.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.658-660
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• 2005

최근 인터넷의 성장과 CDMA등의 무선 통신의 활성화로 인하여 이동 중인 차량 내에서 다양한 정보를 사용하기 위한 기술이 개발 중이다. 본 논문에서는 차량 단말에 여러가지 텔레매틱스 서비스를 제공하기 위한 차량 단말, 텔레매틱스 서비스 서버, 텔레매틱스 컨텐츠 서버의 3단계 구조를 가지는 텔레매틱스 서비스 시스템을 제안한다. 제안하는 시스템은 차량 단말과 서비스 서버 사이의 통신 방법 및 서비스 서버 내의 서비스 응용이 다양한 컨텐츠를 제공하기 위한 프레임워크를 제공한다.

• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.39-49
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• 1999

This paper describes a 1 GHz, low-phase-noise CMOS fractional-N frequency synthesizer with an integrated LC VCO. The proposed frequency synthesizer, which uses a high-order delta-sigma modulator to suppress the fractional spurious tones at all multiples of the fractional frequency resolution offset, has 64 programmable frequency channels with frequency resolution of $f_ref/64$. The measured phase noise is as low as -110 dBc/Hz at a 200 KHz offset frequency from a carrier frequency of 980 MHz. The reference sideband spurs are -73.5 dBc. The prototype is implemented in a $0.5{\mu}m$ CMOS process with triple metal layers. The active chip area is about $4mm^2$ and the prototype consumes 43 mW, including the VCO buffer power consumption, from a 3.3 V supply voltage.

• ETRI Journal
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• v.35 no.6
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• pp.1075-1083
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• 2013

This paper describes an ultra-wideband (UWB) antenna that uses a ring resonator concept. The proposed antenna can operate in the entire UWB, and the IEEE 802.11a frequency band can be rejected by inserting a notch stub into the ring resonator. The experiment results indicate that the measured impedance bandwidth of the proposed antenna is 17.5 GHz (2.5 GHz to at least 20 GHz). The proposed UWB antenna has omnidirectional radiation patterns with a gain variation of 3 dBi (1 dBi to 4 dBi).

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.47-52
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• 2006

In this paper, we suggested new network architecture to provide seamless service between the cellular system and new wireless broadband network such as IEEE 802.16e, called WiBro. The interworking technologies are very important issue because mobile operator should provide service connectivity between various wireless networks based on different access technologies. Moreover a change and modification on legacy network should be minimized for providing interworking with new wireless broad-band network. We implemented proposed interworking architecture between 3G cellular network and 802.16e network to provide seamless service including interworking unit in real test environment. Also, we performed performance evaluation in hybrid network environments.