• 분석과학
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• 제28권3호
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• pp.168-174
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• 2015

남조류 독소인 마이크로시스틴은 여름철 우리나라 여러 호수들에 존재하여 물고기와 가축 그리고 인간에게 강한 독성을 나타내는 독소이다. 본 논문에서는 이러한 수중 남조류 독소, 마이크로시스틴을 정량분석하는 두가지 방법, 즉 고성능 액체크로마토그래피(HPLC) 분석법과 최근 우리 실험실에서 개발한 스트립분석법의 비교를 시도하였다. 두 분석법의 측정가능농도범위가 많이 달라 HPLC 법으로 먼저 측정한 후 시료를 물로 희석시켜 스트립분석법에 적용하였다. 서로 다른 농도의 마이크로시스틴을 함유한 7가지 물시료들을 사용하여 HPLC분석법과 스트립 분석법으로 남조류 독소 총량을 측정하였다. 그 결과 두 분석법의 정량측정결과가 매우 잘 일치하는 것을 볼 수 있었다. 두 분석법의 상관분석 결과 r 값은 0.99998 이었으며 통계적인 유의성을 나타내는 p 값은 0.00001 이었다.

• 한국지반공학회논문집
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• 제19권5호
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• pp.163-173
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• 2003

본 연구에서는 억지말뚝으로 보강된 사면에서 한계평형 해석법과 3차원 해석 결과를 비교 분석하였다. 특히, 유한차분법을 이용한 FLAC 3D를 바탕으로 하는 커플링 해석에 주안점을 두었으며, FLAC을 이용하여 전단강도감소기법에 따른 보강사면의 안전율을 계산하기 위해 FLAC의 내장언어인 FISH를 이용하여 작성하였다. 커플링 해석에서 억지말뚝에 의한 안정화된 사면을 해석하기 위해 말뚝의 거동과 사면안정을 동시에 고려하였다. 따라서 본 연구에서는 이 두 방법을 적용하여 일렬 억지말뚝이 사면선단, 중앙부, 정부에 위치할 경우에 있어서 각각의 활동 파괴면 및 안전율을 비교 분석하였으며 강도정수 감소법을 적용한 해석기법의 적용성과 타당성에 대한 분석을 수행하였다.

• 한국해양공학회지
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• 제20권2호
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• pp.1-7
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• 2006

This paper, presents a comparison between numerical analysis and field test on a real offshore platform in Bohai Bay, China. This platform is a steel jacket offshore platform with vertical piles. The field testing under wave-induced force and wind force etc. was conducted, in order to obtain the dynamic parameters of the structure, including the frequencies of the jacket platform, as well as the corresponding damping ratios and mode shapes. The natural excitation technology (NexT) combined with eigensystem realization algorithm (ERA) and the peak picking (PP) method in frequency domain are carried out for modal parameter indentification under operational conditions. The three-dimeansional finite element model (FEM) is constructed by ANSYS and analytical modal analysis is performed to generate modal parameters. The analytical results were compared with experimental results. A good agreement was achieved between the finite element and analysis and field test results. It is further demonstrated that the numerical and experimental modal analysis provide a comprehensive study on the dynamic properties of the jacket platform. According to the analysis results, the modal parameters identification under ambient excitation can calibrate finite element model of the jacket platform structures, or can be used for the structural health monitoring system.

• 마케팅과학연구
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• 제16권4호
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• pp.39-54
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• 2006

기업의 마케터들은 어느 때보다 빨라진 소비자 욕구의 변화와 경쟁제품 출시에 대응하여 신제품 성공의 확률을 극대화시키려 노력한다. 소비자의 욕구에 맞는 신제품을 개발하기 위해 활용되는 기법 중 하나가 컨조인트분석이다. 본 논문은 컨조인트기법 중 가장 널리 이용되는 전통적 컨조인트분석과 선택형 컨조인트분석의 예측력을 비교하는데 초점을 맞추었으며 그 대상으로 병원산업을 선택하였다. 모형간 예측력 비교를 위해 전통적 컴조인트분석과 선택형 컨조인트분석 중심으로 4가지 모형을 선정하였다. 분석결과, 전통적 컨조인트와 선택형 컨조인트를 결합한 혼합형 컨조인트기법의 예측력이 가장 높은 것으로 나타났으며, 각 모형에서 추정된 모수간의 일관성도 높은 것으로 나타났다.

• 환경분석과 독성보건
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• 제21권4호
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• pp.229-236
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• 2018

In this study, inter-laboratory comparison was done using elemental analyzer-isotope ratio mass spectrometers (EA-IRMSs) to determine carbon and nitrogen contents as well as stable carbon and nitrogen isotopic compositions (${\delta}^{13}C$ and ${\delta}^{15}N$) of five environmental samples containing lake and marine sediments, higher plant leaves, and fish muscle, and one organic analytical standard (Protein (Casein) Standard OAS). Five national laboratories participated in this comparison study, and each laboratory analyzed all five samples and the analytical standard. Results showed that variations in total organic carbon (TOC) and total nitrogen (TN) contents as well as ${\delta}^{13}C_{TOC}$ and ${\delta}^{15}N_{TN}$ values among the laboratories were large compared to the analytical uncertainties. The results highlighted the inhomogeneity of the test samples and thus, the need to select suitable standard reference materials for future inter-laboratory studies. Further inter-laboratory comparison exercises could promote good measurement practices in the acquisition of stable carbon and nitrogen isotopic composition data.

• 한국의류학회지
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• 제46권1호
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• pp.182-198
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• 2022

Bullying at school results in a variety of psychological and social issues. Even after victims reach adulthood, these issues do not resolve and can have detrimental effects. The purpose of this study is to explore the effect of school bullying victimization on body appreciation in adulthood. Considerations include multi-mediating effects of physical attractiveness comparison and ambivalent emotions toward beauty. A research model comprised of six hypotheses was derived applying the A (adversity)-B (belief)-C (consequence) theory. A survey with 583 South Korean women in their twenties to forties was conducted to collect data. Confirmatory factor analysis, structural equation modeling, and multi-mediation analysis were applied, and all hypotheses were accepted. School bullying victimization had a negative influence on body appreciation in adulthood. Additionally, physical attractiveness comparison and ambivalent emotions toward beauty mediated this causal relationship. Also, the mediating effect of physical attractiveness comparison on the relationship between school bullying victimization and body appreciation was the greatest among the three mediating effects. This study demonstrated that bullying victimization at school continues into adulthood, which hurts body appreciation of adulthood. The findings would contribute to the development of therapy programs for school bullying victims.

• Journal of Positioning, Navigation, and Timing
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• 제12권3호
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• pp.245-255
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• 2023

Time comparison techniques are necessary for generating and keeping Coordinated Universal Time (UTC) and distributing standard time clocks. Global Navigation Satellite System (GNSS) Common View, GNSS All-in-View, Two-Way Satellite Time and Frequency Transfer (TWSTFT), Very Long Baseline Interferometry (VLBI), optical fiber, and Network Time Protocol (NTP) based methods have been used for time comparison. In these methods, GNSS based time comparison techniques are widely used for time synchronization in critical national infrastructures and in common areas of application such as finance, military, and wireless communication. However, GNSS-based time comparison techniques are vulnerable to jamming or interference environments and it is difficult to respond to GNSS signal disconnection according to the international situation. In response, in this paper, Code-Division Multiple Access (CDMA) based All-to-All TWSTFT operation method is proposed. A software-based simulation platform also was designed for performance analysis in multi-TWSTFT signal environments. Furthermore, code and carrier measurement jitters were calculated in multi-signal environments using the designed simulation platform. By using the technique proposed in this paper, it is anticipated that the TWSTFT-based time comparison method will be used in various fields and satisfy high-performance requirements such as those of a GNSS master station and power plant network reference station.

• 한국생산제조학회지
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• 제8권4호
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• pp.106-111
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• 1999

This study discusses a non-contact optical technique electronic, electronic speckle pattern interferometry(ESPI) that is well suited for in-plane and out-of-plane deformation measurement Used as specimen which has the boundary condition of two clamped parallel edges composite material AS4/PEEK[30/-30/90]s was analyzed by ESPI to determined the characteristics of tensile and vibration. These are quantitativly compared with the result of FEM analysis. Finally the results of this study are briefly summarized as follows : (1) In the in-plane strain analysis by comparison of theoretical results with experimental results qualitatively we confirmed that measurement errors are within 3 % in case of accuracy (2) From comparison of experimental vibration modes with numerical vibration mode shapes by the FEM analysis quantitatively we confirmed that vibration mode measurement by the ESPI has high accuacy.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.208-211
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• 2001

In the drawing from round billet to non-circular section there are two different processes through solid hole die(HD) and the other cassette roller dies(CRD). The CRD process has several cassette type rollers and a billet is able to move through the given gaps between two profiled rollers. The objective of this study is based on the analysis and evaluation of two aforementioned processes using experiments and finite element simulation. In order to simulate the multi-stage drawing process from circular sectioned billet to rounded square section, the finite element analysis is applied to the process using a commercially available DEFORM-3D code. Two types of experimental drawing tests through designed and manufactured dies for pure copper and aluminum alloy are carried out at room temperature. The analysis included comparison of material properties before and after drawing of each process and also provide some useful information by a FEM simulation.