• Information and Communications Magazine
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• v.19 no.11
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• pp.24-31
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• 2002

지금까지 SDR을 비판적인 시각으로 검토해 보았다 하지만 분명한 것은 SDR은 disruptive technology의 기능성을 가지고 있다는 점이다. 현재 domain specific하게 vertical market을 구축하고 있는 구현방식을 horizontal market으로 바꿔보자는 발상으로 전체적인 기술과 시장의 대세와 일치하기 때문이다. 저자의 관점은 SDR을 technology-driven 한발상으로 '일단 SDR이다' 라고 revolution으로 접근하는 것은 옳지 않다고 보는 것이다. SDR이란 Hype이 Real이 되려면 (1) power 소모, co-working과 같은 기술적인 문제들이 해결되고, (2) SDR 도입을 지연시키는 시장 환경이 개선되어야 하며, (3) software download, middleware 나 operating system과 관련된 정치적인 문제들이 해결되어야 한다. 이러한 문제들은 하루 아침에 해결되는 것이 아니기 때문에 market-driven한 관점에서 SDR concept이 기존의 장벽들을 극복할 수 있을 때 하나씩 SDR cencept을 채용해가는 evolution으로 접근하는 것이 중요하다. 앞으로도 Moore의 법칙은 15년에서 20년 가까이 지속될 것으로 전망하고 있다. 이미 Moore의 법칙에 의한 기술발전이 수요를 앞서는 조짐이 나타나고 있는 분야도 있어 남아도는 gate를 어떻게 활용할 것인가에 대해 회사마다 다른 전략을 펴고 있다. 특히 TI가 DSP 기반으로 벌인 다양한 사업전력, Intel이 CPU 기반으로 벌이는 Radio Free 사업 전략은 SDR에 대해 많은 시사점을 던져 준다. MMITS Forum에서 시작하여 SDR Forum 초창기, 현재의 SDR Forum 까지 SDR의 개념은 시장의 반응에 따라 변해 왔고, 일부 기술들은 더 이상 SDR 이라는 그늘에 머물지 않고 독자적인 기술군을 형성해 가고 있다. 분명한 것은 SDR 기술은 시장에서의 도전을 바탕으로 끊임없이 변해왔고 앞으로도 변해 갈 것이다. 지금의 비전이 최종적인 것이라고 섣불리 판단하고, 시장의 기술 흐름을 아전인수식으로 해석하고 만병통치 약을 만들려는 시도는 실패 잉태하고 있는 매우 위험한 발상이다. SDR이 꿈꾸는 세상은 이상향임에 틀림없지만 항상 시장을 주도하는 것은 꿈이 아니라 가격 경쟁력이기 때문이다.

• Journal of Internet Computing and Services
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• v.7 no.2
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• pp.121-136
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• 2006

Software architecture and protocols to be maintained between components for the reconfigurable SDR system is analyzed and suggest system design idea for the implementation of software. To do this, related surveys are reviews and set up the system model with the structure of embedded system. SDR system architecture is suggested with five layered structure, consisted with hardware, operating system, middle-ware, service objects and application layer. SDR system is designed to be work on the basis of Linux operating system, and aimed to be scalable and reconfigurable. It is introduced the design result of software protocol and state transition diagram for the implementations of software download function which is the most important feature in SDR.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.335-341
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• 2008

The SDR(Software Defined Radio) system for hardware and software must be an open structure to various system standards. It should also provide a capability of distributed processing, object-orientedness, and software controllability. It implies that the software to be used in the SDR system should provide the openness such that it can operate independently of a given hardware platform. In order to achieve these goals, the SDR system tends to modularization for increasing hardware reuse and design flexibility, which provides the system reconfigurability. In this paper, we implemented a base station with proposed an open architecture of a Smart Antenna Base Station(SABS) and Smart Antenna APIs[10] operating in SDR network in such a way that the architecture itself is suitable for the entire system to maintain the openness, object-orientedness, and software controllability.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.93-101
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• 2011

The modeling of SDR was carried out for the application of the solid waste incineration system. To find optimum operating condition for removal of acidic gases, computation fluid dynamic(CFD) model was used. In this study, the temperature profile of SDR(spray dry reactor) and the gas velocity profile for different models were investigated. In this model, the diameter of SDR was 3 meter and the height of SDR was 9 meter. The amount of inlet combustion gas of SDR was $6,125Nm^3/hr$ and the inlet temperature of SDR was 493 K. The amount of lime injection of SDR was 151 kg/hr. When the inlet shape of SDR was changed, the temperatur of SDR was changed and the gas velocity of SDR was 0.48 m/sec to 1.17m/sec and the outlet gas velocity of SDR was 6.9 m/sec to 7.42m/sec As a result of modeling, the average velocities in SDR and outlet were 0.489 m/sec and 7.424 m/sec, respectively, in which the temperature of outlet in SDR was 448 K.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.321-328
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• 2014

Software defined radar (SDR) is a multi-purpose radar system where most of the hardware processing is performed by software. This paper introduces a concept and technology trends of software defined radar, and addresses the advantages and limitations of the current SDR radar systems. For the advanced SDR concept, the KAU SDR Model (KSM) is presented for the multimode and multiband radar system operating in S-, X-, and K-bands. This SDR consists of a replaceable multiband antenna and RF hardware, common digital processor module with multimode, and open software platform based on MATLAB and LabVIEW. The new concept of the SDR radar can be useful in various applications of the education, traffic monitoring and safety, security, and surveillance depending on the various radar environments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.11
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• pp.949-958
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• 2016

This paper presents the new development result of the multi-band, the multi-mode SDR(Software Defined Radar) platform. The SDR hardware platform is implemented by using the reconfigurable multi-band RF transceiver and antenna modules of S, X, and K-bands, and a programmable signal processing module. The SDR software platform is implemented by using the multi-mode waveform generation of CW, Pulse, FMCW, and LFM Chirp as well as the adaptable algorithm library of signal processing and open API software modules. Through the integrated test of the SDR platform, the operational performance was verified in real-time. Also, through the field-application test, the ground target and air-vehicle drone target were successfully detected and their test results were presented.

• Information and Communications Magazine
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• v.25 no.7
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• pp.47-52
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• 2008

본고에서는 SDR 네트워크를 위한 스마트 안테나 시스템의 표준화에 대하여 알아본다. 스마트 안테나 시스템이 SDR 네트워크에서 동작하기 위해서는 시스템의 개방성, 유연성, 상호 운용성 및 호환성이 보장되어야 한다. 이러한 특성을 위해서는 스마트 안테나 시스템이 소프트웨어 모듈로 잘게 나눠져 컴포넌트화 되어야 하고, 각 컴포넌트를 제어하기 위한 어플리케이션 프로그래밍 인터페이스(API)가 표준화 되어야 한다. 본고에서 제안하는 스마트 안테나API는 한양대학교 HY-SDR 연구센터에서 정의하여 SDR Forum의 공식 표준으로 승인되었으며, 현재 SDR Forum의 공식 표준화 기고 절차를 통해 Object Management Group (OMG)에 제출되어 표준화 작업 중에 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.355-357
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• 2003

최근 급속한 발전으로 인해 다양해지고 있는 무선 통신 기술들은 각자의 고유한 주파수, 채널 부호화 기법. 변복조 기법을 쓰는 경우가 많다. 이로 인해, 다양한 무선 통신 기술간의 비호환성 문제가 제기되고 있다. 이러한 문제를 해결하기 위한 기술이 SDR(Software Defined Radio)이다. SDR은 신호 처리(Signal Processing)를 소프트웨어적으로 구현하는 것이다. 이러한 SDR 기술은 하나의 하드웨어를 이용해서 설러 무선 통신 기술들을 이용할 수 있게 한다. 현재 대부분의 SDR의 연구는 재구성 가능한 하드웨어 로직과 코어 프레임워크인 SCA(Software Communication Architecture)로 초점이 맞추어지고 있다 하지만 SDR 시스템의 특성을 고려했을 때, 실시간성(Real-Time)과 유연성(Flexibility), 재구성(Reconfigurability)을 위한 기능을 추가하기 위해 이에 적합한 운영체제의 연구가 필요하다. 본 논문에서는 휴대 기기에서의 SDR 시스템에 대해 간략히 알아보고 이를 위한 운영체제의 요구사항을 설명하여 그에 적합한 운영체제의 구조와 재구성 기법을 설명한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.387-393
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• 2008

In this paper, we present an SDR (Software Defined Radio) handset modem platform which supports communication systems such as HSDPA (High Speed Downlink Packet Access), and WiBro (Wireless Broadband Portable Internet). The proposed SDR platform employs DSPs (Digital Signal Processors), FPGAs (Field Programmable Gate Arrays), and microprocessors in such a way that the various communication functions like HSDPA and WiBro can be programmed and downloaded to the hardware platform. The proposed SDR platform can be used for functional verification of the physical layers of the mobile handset system in the mobile communication network. We first demonstrate the receiving structure of the physical layer of the HSDPA and WiBro system. Then, the hardware implementation of the proposed SDR platform is shown with functions and optimized signal flows required at each mode. Finally, the link performance of each mode operating on the proposed SDR platform is presented through the internal loopback tests with the test vectors. The experimental performance has been compared with the computer simulation results.

• Journal of Korean Society on Water Environment
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• v.33 no.6
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• pp.744-753
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• 2017

The sediment delivery ratio (SDR) is widely used to estimate sediment loads by multiplying soil loss through the Revised Universal Equation (RUSLE). In this study, the SDR equation was developed for the Lake Imha watershed using soil loss calculated by RUSLE and sediment loads by the calibrated Hydrological Simulation. Program Fortran (HSPF). The ratio of watershed relief and channel length ($R_f/L_{ch}$), the ratio of watershed relief and watershed length ($R_f/L_b$), curve number (CN), area (A), and channel slope ($SLP_{ch}$) demonstrated strong correlations with SDR. SDR equations were developed by a combination of subwatershed parameters by referring to the correlation analysis. The area based power functional SDR developed in this study showed significant errors at the point right after entering major tributaries, because SDR was unrealistically reduced when the watershed area increased significantly. The $SLP_{ch}$-based power functional SDR also showed extraordinary values when the channel slope was gradual. The SDR equation that showed the highest value of the coefficient of determination also presented unrealistic changes in the sediment loads within a relatively short river distance. The SDR equation $SDR=0.0003A^{0.198}R_f/L{_w}^{1.167}$ was recommended for application to the Lake Imha watershed. Using this equation, sediment loads at the outlet of the Lake Imha watershed were calculated, and the HSPF parameters related to sediment in the uncalibrated subwatersheds were determined by referring to the sediment loads calculated with the SDR equation.