• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1C
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• pp.77-86
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• 2010

In this paper, we present a noncoherent IR-UWB (Impulse Radio-Ultra Wide Band) ranging system with an AFE (Analog Front End) composed of a simple integrator and an 1-bit ADC (Analog-to-Digital Converter), and define AFE characteristics affecting the ranging performance. This system is realistic and easy to implement, since the integrator simply accumulates signal energies and the simple 1-bit ADC is applied instead of the multi-bit ADCs for coherent IR-UWB systems. On the other hand, its ranging accuracy is largely affected channel environments such as noise, multipath fading and so on, since the noncoherent receiver simply squares and integrates the received signals. However, despite these practical importances, there are few conventional researches on the performance analysis according to AFE characteristics in IR-UWB ranging systems. To this end, we analyze in this paper ranging performance according to AFE characteristics for the noncoherent IR-UWB ranging system in various wireless channel environments, and through these results we also present system parameters to be considered in UWB hardware designs.

• Digital Contents
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• no.9 s.52
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• pp.72-77
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• 1997

SAS는 데이터 웨어하우스 추출에서 저장, OLAP, DSS, 마이닝에 이르기까지의 전 과정에 대한 솔루션을 제공한다. 지난 20년간 의사결정지원 분야에서 탁월한 기능으로 세계적으로 명성을 얻고 있는 SAS는 데이터 웨어하우징 분야에서도 Back-End와 Front-End에 있어서의 뛰어난 기능을 바탕으로 의사결정 지원을 위한 최적의 데이터 웨어하우징 솔루션을 제공하고 있다.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.290-294
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• 2001

인터넷 우편 시스템은 인터넷에서 고객이 작성한 우편을 메일 뿐만 아니라 이를 직접 인쇄하여 다수의 수신자에게 보통우편으로 제작하여 직접 배달하는 우편서비스로 인쇄부터 봉함가지 자동으로 처리하는 시스템이다. 따라서 직접적인 우편을 전달함으로서 기존의 디지털 문명의 의한 각박해진 현 사회에 보다 인간미가 넘치는 매개체로서의 역할과 획기적인 시간 단축과 비용절감의 효과를 누리고자 한다. 현 인터넷 우편 시스템은 크게 3가지로 Front Agent End Agent, Management Agent 나뉘어 지는데 본 논문에서는 Front Agent를 중심으로 서술하였다.

• The Transactions of the Korea Information Processing Society
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• v.4 no.3
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• pp.831-845
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• 1997

In this paper,we proposed and developed a compiler and interactive programming enviroments for C++ wich is mostly worth of nitice among the object -oriented languages.To develope the compiler for C++ we took front=end/back-end model using EM virtual machine.In develpoing Front-End,we formailized C++ gram-mar with the context semsitive tokens which must be manipulated by dexical scanner and designed a AST class li-brary which is the hierarchy of AST node class and well defined interface among them,In develpoing Bacik-End,we proposed model for three major components :code oprtimizer,code generator and run-time enviroments.We emphasized the retargatable back-end which can be systrmatically reconfigured to genrate code for a variety of distinct target computers.We also developed terr pattern matching algorithm and implemented target code gen-erator which produce SPARC code.We also proposed the theroy and model for construction interative pro-gramming enviroments. To represent language features we adopt AST as internal reprsentation and propose uncremental analysis algorithm and viseal digrams.We also studied unparsing scheme, visual diagram,graphical user interface to generate interactive environments automatically Results of our resarch will be very useful for developing a complier and programming environments, and also can be used in compilers for parallel and distributed enviroments.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.558-561
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• 2000

본 연구에서는 Web 기반 사용자 인터페이스를 사용하여 일반적인 수학 모형을 만드는 Web기반 클라이언트/서버 시스템의 구현 방법을 제시하고, 수학모형을 위한 데이터 베이스 설계 방법을 소개한다. 수학 모형을 설계하고 구현하기 위해서는 방대한 양의 데이터 처리가 반드시 필요하며 이를 위하여 데이터베이스를 수학 모형에 맞게 설계함으로써 보다 효과적으로 수학 모형을 구현 할 수 있다. 한편 Web을 이용한 클라이언트/서버 구조는 사용자가 Web Browser 만으로 프로그램을 이용할 수 있다. 본 연구에서는 3계층 데이터베이스 접근 모델을 갖는 Web기반 클라이언트/서버 구조를 설계하였으며, Front-End를 Java Applet을 사용하고, Back-End로써 실제 수학 모형을 만들어주는 Java Application 서버를 구현하며 Front-End와 Back-End 사이의 통신을 담당하는 네트웍 아키텍처로 자바 소켓을 사용한다. 일반적인 수학모형을 데이터베이스를 이용하여 구현함으로써 수리계획, 일정계획, 물류관리 등 수학 모형을 이용하여 최적화 결과를 도출하고자 할 때, 입력 부분과 출력 부분의 사용자 인터페이스만 구현하여 붙여주면 쉽게 응용하여 확장할 수 있다.

• Journal of Auto-vehicle Safety Association
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• v.6 no.2
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• pp.5-11
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• 2014

Front side member of the front impacted vehicle plays a key role in minimizing the impacting load transferred to the compartment. To perform that required function, axial collapse should be dominant during side member crashing and, prior to designing side member, it is crucial to minimize bending moment occurred at the front end. In this study, for FE model of a SUV front body, front impact analyses were carried to find out bumper stay design which effectively develope axial collapse in the side member. As a previous work, the thickness of side member reinforcement were changed. Next, the inner thickness of bumper stay was increased. Also, the bead shape and location were modified. Final front body model showed much more axial collapsed mode and enhanced crash performance. In addition, a stay of octagon section was adopted and that model exhibited distinctive increase in impact energy absorption.

• The KIPS Transactions:PartA
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• v.11A no.5
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• pp.355-364
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• 2004

These days, various clustering technologies have been adopted to construct web sites. High performance hardware switches have good performance, but have disadvantage of high cost for constructing small and middle-sized web sites. Now a days, many sites have been constructed with the LVS (Linux Virtual Server), which is free of charge and has good performance. Having a centralized load balancing with one front-end, the LVS causes a bottleneck when it receives all at once. In the paper, we suggest a way to remove the LVS bottleneck by providing multiple front-ends. In this architecture, all of cluster nodes act as both a front-end and a back-end. When the load of a node receiving requests is not large enough, the node responds to the client directly. When the load of a node is large enough, the node send the request to a node which is selected by a scheduling algorithm. The scheduling algorithm is discussed to balance loads between servers. While single front-end cluster raises the throughput curvedly, the multiple front-end cluster raises the throughput linearly.

• Journal of IKEEE
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• v.13 no.1
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• pp.41-48
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• 2009

This paper describes an implementation of the analog front end (AFE) incorporated with the image signal processing (ISP) unit in the SoC, dominating the performance of the CCD image sensor system. New schemes are exploited in the high-frequency sampling to reduce the sampling uncertainty apparently as the frequency increases, in the structure for the wide-range variable gain amplifier (VGA) capable of $0{\sim}36\;dB$ exponential gain control to meet the needed bandwidth and accuracy by adopting a new parasitic insensitive capacitor array. Moreover, the double cancellation of the black-level noise was efficiently achieved both in the analog and the digital domain. The proposed topology fabricated in a $0.35-{\mu}m$ CMOS process was proved in a full CCD camera system of 10-bit accuracy, dissipating 80 mA at 15 MHz with a 3.3 V supply voltage.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.8
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• pp.767-773
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• 2008

Galileo is a new civil Global Navigation Satellite System(GNSS) developed by Europe. GIOVE-A, a satellite to test Galileo system performance, transmits navigation signal on orbit. Evaluation of Galileo system and development of Galileo receiver needs to analyze GIOVE-A signals. In this paper, we received GIOVE-A signals and processed it using GIOVE-A Interface Control Document(ICD). Signal acquisition, tracking and navigation message decoding made grasping current signal status possible. Bandwidth increase by BOC modulation is one of the difference from GPS. Therefore, we investigated feasibility of conventional GPS L1 RF front-end to receive GIOVE-A E1 signal by evaluation of receiving performance of navigation signal on each bandpass filter of RF front-end.

• The Journal of Natural Sciences
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• v.5 no.2
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• pp.25-32
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• 1992

Statistical database(SDB) are large database primarily collected for purpose of statistical analysis. Commerical database management systems have not been widely used for SDB because of the efficiency problem of storage and access of those systems for SDB. In this paper, we propose SDB management method to use a front-end system to a Relatianal Datebase Management System (RDBMS). We do the design of SM-F system (Stasticical database Management as Front-end system) as a front-end system to a RDBMS. In the system, we use GROS model specially proposed for SDB, and store and manage summary database and meta database to support statistical analysis and to provide users with statistical summary information.