• 한국군사과학기술학회지
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• 제19권3호
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• pp.379-386
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• 2016

In this paper, phase noise analysis result for 2.4 GHz PLL(phase locked loop) using SPD(sample phase detector) is proposed. It can be used for high performance frequency synthesizer's LO(local oscillator) to extend output frequency range or for LO of offset PLL to reduce a division rate or for clock signal of DDS(direct digital synthesizer). Before manufacturing, theoretical estimation of PLL's phase noise performance should be performed. In order to calculate phase noise of PLL using SPD, Leeson model is used for modeling phase noise of VCO(voltage controlled oscillator) and OCXO(ovened crystal oscillator). After theoretically analyzing phase noise of PLL, optimized loop filter bandwidth was determined. And then, phase noise of designed loop filter was calculated to find suitable OP-Amp. Also, the calculated result of phase noise was compared with the measured one. The measured phase noise of PLL was -130 dBc/Hz @ 10 kHz.

• FOCUS: LIFE SCIENCE
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• 제1호
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• pp.6.1-6.9
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• 2024

The document is a white paper on Hydrophilic Interaction Liquid Chromatography (HILIC) analysis method development. HILIC is a type of chromatography that uses an organic/aqueous mobile phase and a polar stationary phase. In HILIC, water is a strong solvent, and unlike in Reversed Phase Liquid Chromatography (RPLC), increasing the proportion of water in the mobile phase reduces the retention time of the analyte. The paper discusses when to consider HILIC analysis methods, the advantages of HILIC, and the challenges often encountered due to the lack of understanding of HILIC mechanisms compared to RPLC. It also provides a systematic flowchart for intelligent solutions for HILIC analysis method development, which includes a three-step approach for chromatography analysis method development. The first step involves gathering as much information as possible about the analyte (e.g., pKa, log P, log D). The second step involves analyzing the sample under different pH conditions using three HILIC columns in either isocratic or gradient mode to identify the suitable column/pH combination for the analyte. The third step involves optimizing the separation by investigating other parameters such as temperature and ionic strength, and assessing the robustness of the method. The paper emphasizes that the selection of the appropriate stationary/mobile phase combination, based on the differences between the HILIC stationary phases and the mobile phase pH, can provide high selectivity in the analysis. This step-by-step approach can help users develop an efficient analysis method.

• 한국컴퓨터정보학회논문지
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• 제21권11호
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• pp.79-83
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• 2016

In this paper, we define four levels of analysis, design, implementation, and testing of the configuration of the development phase by S/W development life cycle. In particular, it dealt with the stage of the analysis phase to prepare an information system developed intensively. Details of the derivation of the information security requirements, it can be seen that comes from the perspective of confidentiality, integrity, availability and accountability, etc. It dealt with from the first manifestations of the projects planning to final planning to establish information security in activities of the Information Security requirements. As an example exhibited by assessing the information security analysis phase activities of S corporations, it can be seen that the improved sales rise in information security activities.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.408-413
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• 2004

민간 개발 프로젝트의 초기 기획단계는 프로젝트 전체의 성패를 좌우하는 중요한 부분이다. 하지만 기존의 기획단계 분석결과의 신뢰도는 중요도에 비해 높지가 않다. 따라서 기존 민간 개발 프로젝트 기획단계의 사례연구 및 연구자료 분석을 통해 근원적인 문제점을 분석하였다. 그 결과 기획단계의 업무 절차나 방법에 관한 체계적 분석 모델의 구축이 되지 않은 것에 그 원인이 있는 것으로 나타났다. 이에 본 연구에서는 그 해결방법으로 기획단계 분석절차 모델과 리스크 관리 모델 구축을 통해 체계적 분석방법을 제시하고자 한다. 제시된 분석방법은 기획단계 분석결과의 신뢰성을 증대시킬 수 있을 것으로 기대된다. 이와 함께 프로젝트 진행단계별 가이드라인을 제시함으로써, 프로젝트의 효율적 수행을 지원할 것으로 기대된다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권5호
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• pp.297-304
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• 2000

The motor for torpedo propulsion is needed the compact and short rating high power characteristics. This paper describes the development of the motor through the theory and Finite Element Method(FEM) analysis for Brushless Direct Current Motor(BLDCM) of 7 phase 6 poles. Back EMF, inductance and eddy current loss were analyzed. The proposed methods like magnetic wedge acquired by these FEM analysis were introduced. Phase-leading angle using encoder was used. Test results on the motor of 7 phase 6 poles were showed the validity of proposed methods and phase-leading angle.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.381-383
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• 2001

A system engineering play a key role in new signalling system development. The signalling system development process consists several phases which are requirement analysis, functional analysis, system synthesis and system analysis. Each phase of the development are decomposed according to system engineering process. The key topics to be considered are shown in the each phase such as safety. This paper shows the application of system engineering process to a signalling system development.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1998년도 국제 컨퍼런스: 국가경쟁력 향상을 위한 디지틀도서관 구축방안
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• pp.448-474
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• 1998

Data warehouse (DW) is important for analytical processing. Metadata is a key to its architecture. This paper proposes an architecture that consists of seven components. To illustrate data warehouse environment (DWE), this Paper proposes taxonomies having four flows. on the basis or the taxonomies and metadata, this paper proposes a methodology for building the data warehouse and metadata simultaneously. This integrated development methodology (IDM) consists of seven phases: (i) preparatory phase, (ii) requirement analysis phase, (iii) data warehouse development phase, (iv) operational data store development phase, (v) data mart development phase, (vi) metastore development phase, and (vii) maintenance phase. A metastore system is Proposed to help develop metadata interactively. An illustrative example is investigated to demonstrate the usefulness of IDM.

• 농촌계획
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• 제19권4호
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• pp.33-46
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• 2013

The present study aims to provide an analytical framework for achieving aid and development effectiveness of agricultural cooperation with a demand-oriented perspective. This paper pays particular attention to categorize the stages of agricultural development of African recipients to identify demands for agricultural aid of the categorized groups. To do so, first of all, it establishes theoretical background to apply the demand-oriented concept and utilize the phase of agricultural development as an alternative for aid and development effectiveness. On the basis of the theoretical robustness, it conducts a series of analyses to categorize the African recipients by the development stages, incorporating factor analysis, cluster analysis and comparison between the present-future agricultural development levels. The findings propose analysis indicators for phase of agricultural development and clustered results including 18 countries of KAFACI members and priority countries in Africa. In addition to the practical application of the results, the methodological flow can be used as steps for sketching a future roadmap to construct the demand-oriented ODA(Official Development Assistance) plan. This paper also offers implications regarding ODA strategy of Korea in response to the phase of agricultural development and the aid demands.

• 한국군사과학기술학회지
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• 제17권5호
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• pp.604-610
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• 2014

In this paper, the analysis and the experiment of independent multi-phase BLDC motor are performed. The back-emf, iron loss analysis are performed by the finite element method and compared with experimental results. The independent multi-phase BLDC motor is manufactured and to measure the efficiency of the motor, evaluation system is also manufactured including the load generator. By comparing the analytic and the experimental results, the effectiveness of the analysis model is verified when calculating the efficiency of the motor.

• 전기학회논문지
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• 제62권4호
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• pp.510-516
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• 2013

This paper suggests a 3-phase series-resonant type high voltage capacitor charger for an EML pulsed power system. The operating principle on the charger is explained by an equivalent circuit. Additionally, we analyze the charging characteristic in one discontinuous conduction mode and three continuous conduction modes. The analysis shows that the resonant current per phase is two thirds of the 3-phase charger's average charging current and one third of the single-phase charger's average charging current with the same capacity. We suggest a design method of the 3-phase capacitor charger in each operational mode and present an example of 3.5 kW capacitor charger at ${\omega}_s=0.33{\omega}_r$. The 3.5 kW 3-phase capacitor charger prototype is assembled with a TI28335 controller and a 40 kJ, 7 kV capacitor. The design rules based on the analysis are verified by experiment.