• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.196-199
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• 2004

This paper presents a structure of the searcher using the space diversity in array antenna system operating in the DS/CDMA signal environments. The new technique exploits the fact that the In-phase and Quadrature components of interferers can respectively be viewed as independent Gaussian noise at each antenna element in most practical CDMA (Code Division Multiple Access) signal environments. The proposed PN acquisition scheme is a single dwell serial PN acquisition system consisting of two stage, that is, the searching stage and the verification stage. The searching stage correlates the received signals with the local PN oscilator for obtaining the synchronous energy at the entire uncertainty region. The verification stage compares the searching energy with the optimal threshold, which is pre-designed in the Lock-Detector, and decides whether the acquisition is successful or fail. In this paper, we analyzed the relationship of both diversity order and the mean acquisition time. In general, It is known that the mean acquisition time decreases significantly as the number of antenna elements increases. But, the enhancement of the performance is saturated in terms of PN acquisition scheme. Therefore, to decrease the mean acquisition time, we must design the optimal array antenna system by considering the operating SNR range of the receiver, the detection probability, and the false alarm probability. The performance of the proposed acquisition scheme is analyzed in frequency-selective Rayleigh fading channels. In this paper, the effect of the number of antenna elements on acquisition scheme is considered in terms of the detection probability, false alarm probability. and the mean acquisition time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.538-540
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• 2004

Electrical currents generated by human heart activities create magnetic fields represented by MCG(MagnetoCardioGram). Since an MCG signal acquisition system requires precise and stable operation, the system adopts hundreds of SQUID(Superconducting QUantum Interface Device) sensors for signal acquisition. Such a system requires fast real-time data acquisition in a required sampling interval, i.e., 1 mili-second for each sensor. This paper presents designed hardware to acquire data from 256-channel analog signal with 1 ksamples/sec speed, using 12-bit 8-channel ADC devices, SPI interfaces, parallel interfaces, 8-bit microprocessors, and a DSP processor. We implemented SPI interface between ADCs and a microprocessor, parallel interfaces between microprocessors. Our result concludes that the data collection can be done in $168{\mu}sec$ time-interval for 256 SQUID sensors, which can be interpreted to 6 ksamples/sec speed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1289-1293
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• 2010

A slipring or FORJ are usually adopted in order for power supply of Geo-centrifuge and input/output data acquisition. Since using slipring causes quite a lot electrical noise, an optical communication using FORJ becomes more general for data acquisition. Such data acquisition devices, however, require frequent maintenance and replacement due to deterioration by long term usage. DICT has set up a real-time wireless date acquisition system using wireless communication technology instead of FORJ. The system enables a remote measurement at any inertial acceleration field up to 100g level and provides as same performance as FORJ. The priority of this system is to use a normal modem substituting a special FORJ.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 2003년도 종합학술대회 논문집
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• pp.197-203
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• 2003

The purpose of the study is to develop an integrated knowledge structuring system for the domain of engineering, in which ontology-based literature mining, knowledge acquisition, knowledge integration, and knowledge retrieval are combined using XML-based tag information and ontology management. The system supports combining different types of databases (papers and patents, technologies and innovations) and retrieving different types of knowledge simultaneously. The main objective of the system is to facilitate knowledge acquisition and knowledge retrieval from documents through an ontology-based dynamic similarity calculation and a visualization of automatically structured knowledge. Through experimentations we conducted using 100,000 words economic documents reported in the "Go！ Japan" project for analyzing Japanese industrial situation, and 100,000 words molecular biology Papers, we show the system is Practical enough for accelerating knowledge acquisition and knowledge discovery from the information sea.

• 한국산학기술학회논문지
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• 제8권5호
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• pp.1087-1091
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• 2007

본 논문은 인간의 언어 획득 원리를 반영한 계산주의적 한국어 어휘 자동 획득 시스템을 제안한다. 제안하는 시스템은 인간의 언어 생활을 모델링한 한국어 코퍼스를 입력 받아 언어 인식을 위하여 사용할 수 있는 어절 사전과 형태소 사전의 어절과 형태소를 자동으로 획득할 수 있다. 1천만 어절 크기의 한국어 코퍼스를 이용하여 실험한 결과, 2,097개의 어절과 3,488개의 형태소를 획득할 수 있었다. 획득된 2,097개의 어절의 출현 빈도의 합은 1천만 어절의 38.63%에 해당하였고 형태소 추출의 정확도는 99.87%를 보였다.

• Journal of Positioning, Navigation, and Timing
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• 제2권1호
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• pp.1-8
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• 2013

A signal system for improving the code acquisition complexity of Global Navigation Satellite System (GNSS) receiver is proposed and the receiving correlator scheme is presented accordingly. The proposed signal system is a hierarchical code type with a duplexing configuration which consists of the Zadoff-Chu (ZC) code having a good auto-correlation characteristic and the Pseudo Random Noise (PRN) code for distinguishing satellites. The receiving correlator has the scheme that consists of the primary correlator for the ZC code and the secondary correlator which uses the PRN code for the primary correlation results. The simulation results of code acquisition using the receiving correlator of the proposed signal system show that the proposed signal scheme improves the complexity of GNSS receiver and has the code acquisition performance comparable to the existing GNSS signal system using Coarse/Acquisition (C/A) code.

• 정보보호학회논문지
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• 제34권2호
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• pp.179-192
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• 2024

macOS는 Apple 사의 제품군에서만 사용할 수 있고 독자적인 시스템 구조, 비공개 커널, 시스템 무결성 보호를 위한 SIP(System Integrity Protection) 등의 보안 기능 등으로 인해 기존에 알려진 메모리 데이터 수집 도구들이 실제로는 제대로 작동하지 않거나 시스템 재부팅을 필수적으로 동반해야 한다는 문제가 있다. 따라서 본 논문은 macOS와 관련된 메모리 포렌식 관련 연구들과 알려진 도구들의 현황 및 한계점을 분석하고 다양한 macOS버전을 대상으로 메모리 수집과 분석을 위한 방법을 연구했다. 그 결과 OSXPmem과 dd 도구를 사용하여 시스템 재부팅 없이 메모리 데이터를 수집하고 Volatility 2, 3를 활용하여 메모리 데이터를 분석하는 디지털 포렌식 조사에서 실무적으로 활용할 수 있는 메모리 수집 및 분석 프로세스를 개발했다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제7권2호
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• pp.73-87
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• 2007

In this paper, based on the American weapon acquisition management framework in DoD Instruction 5000.2 "Operation of the Defence Acquisition System" and the contents of "DoD Guide for Achieving Reliability, Availability, and Maintainability" published by Defense Acquisition University, the kinds and roles of technical reviews are introduced and the identification of RAM related tasks which are performed at levels of technical reviews during acquisition process are considered. And the task allocations for developers, development managers, and users are proposed. Finally the relationships of acquisition management framework, technical reviews and RAM tasks are tabulated.

• Journal of Biosystems Engineering
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• 제10권2호
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• pp.19-26
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• 1985

This study was carried out to develop a versatile data acquisition/processing system for overall tractor performance utilizing a NEC PC-8001 microcomputer. The data acquisition system measures drawbar pull and power, wheel torque and axle power, ground speed, wheel slip, fuel flow, and engine speed. The system stores hexadecimal data for these variables in memory. Upon completion of each test run, all hexadecimal data stored in memory are recorded on floppy disc. The data processing system reads in the data collected on floppy disc and interprete them using several graphical and statistical techniques. The system uses the same microcomputer and a dot-matrix printer. The data acquisition system has been installed on a GOLDSTAR 500 tractor (2WD, 50 ps). A field study has shown that tractor performance data can be quickly and easily collected. It also appeared that the data processing system can be used to efficiently analyze the collected data. The data acquisition system has some troublesome in mounting and handling on tractor since it uses a general-purpose computer consisting of several components.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2007년도 추계학술발표회
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• pp.145-148
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• 2007

본 연구에서는 기기의 감시 및 분석을 위해 필요한 데이터 획득 시스템의 개발에 관해 논의한다 선박에서의 회전기기 및 운전기기의 운전상태 감시와 분석을 위해서는 시스템에 적합한 데이터 획득시스템을 구축하여야 하고 이러한 데이터 획득 시스템을 간단하고 경제적으로 구성하는 것은 중요하다고 할 수 있다. 아울러 사용 환경 혹은 사용자 인터페이스를 사용자의 의도에 따라 손쉽게 변경할 수 있어야 할 것이다. 본 연구에서는 이러한 데이터 획득 시스템을 구성하기 위한 기본적인 요소들에 대해 살펴보고, 일정시간 동안 자동적으로 데이터를 저장하는 방법과 네트웍을 통해 데이터를 획득하는 시스템 구성에 관해 논의한다. 최종적으로 실제 계측을 통해 구성된 데이터획득 시스템이 유용성을 확인한다.