• Geophysics and Geophysical Exploration
• /
• v.9 no.1
• /
• pp.102-107
• /
• 2006

Recently, rapid developments in computer hardware have enabled reverse-time migration to be applied to various production imaging problems. As a wave-equation technique using the two-way wave equation, reverse-time migration can handle not only multi-path arrivals but also steep dips and overturned reflections. However, reverse-time migration causes unwanted artefacts, which arise from the two-way characteristics of the hyperbolic wave equation. Zero-lag cross correlation with diving waves, head waves and back-scattered waves result in spurious artefacts. These strong artefacts have the common feature that the correlating forward and backward wavefields propagate in almost the opposite direction to each other at each correlation point. This is because the ray paths of the forward and backward wavefields are almost identical. In this paper, we present several tactics to avoid artefacts in shot-domain reverse-time migration. Simple muting of a shot gather before migration, or wavefront migration which performs correlation only within a time window following first arriving travel times, are useful in suppressing artefacts. Calculating the wave propagation direction from the Poynting vector gives rise to a new imaging condition, which can eliminate strong artefacts and can produce common image gathers in the reflection angle domain.

• Journal of Korean Library and Information Science Society
• /
• v.33 no.3
• /
• pp.235-256
• /
• 2002

The purpose of this study is to suggest a reform after detecting out issues and problems associated with the KCR 4th ed.(draft). KCR(Korean Cataloguing Rules) is representative cataloguing rules in Korea, the 4th ed.(draft) of which was prepared by Cataloguing Committee(department of KLA) in 2001. As a result of this study, a lot of problem which are glossary, context, inconsistency of the contents, rules applied to card catalog, and others, were found out. Thus, substantial improvements were able to be suggested.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.4
• /
• pp.373-378
• /
• 2012

The objective of this research is to examine the probabilistic approach to evaluating turbine ejection frequency considering common-cause failure. This paper identifies basic turbine ejection mechanisms under high and low speeds and presents a detailed probabilistic methodology (fault tree) for assessing ejection frequency. The alpha factor methodology is applied to common-cause failure evaluations. The frequencies under different test schemes are compared and the propagation of uncertainty through the fault tree model is evaluated. The following conclusions were reached: (1) the turbine blade ejection frequency due to ductile failure under high speed is around 8.005E-7/yr; (2) if common-cause failure is considered, the frequency will be increased by 11% and 33% depending on the test scheme; and (3) if the parameter uncertainties are considered, the frequency is estimated to be in the range of 9.35E-7 to 1.13E 6, with 90% confidence.

• Information and Communications Magazine
• /
• v.32 no.5
• /
• pp.36-41
• /
• 2015

스마트 팩토리는 시시각각 변화하는 생산현장의 생산정보 4M1E(Man, Machine, Material, Method, Energy)생산 자원을 실시간으로 통합하여 생산 관리를 무대기시간, 무재고, 무고장, 무불량일 발생할 수 있는 핵심성과지표(KPI: Key Performance Indication)를 통하여 생산현장을 연속개선을 추진하는 것이 핵심이다. 본고에서는 스마트 제조업에 필요한 IT융합 국제표준화 동향으로 사이버 보안기술, Object Process Methodology기반 생산자원 통합기술, 실시간 이벤트기반 구조화 기술, 공통 생산정보화 플랫폼 서비스기술, 생산정보화 표준기능 및 국제표준동향과 한국형 중소제조업 스마트공장 적용 참조 모델에 대하여 알아본다.

• The Magazine of the IEIE
• /
• v.43 no.6
• /
• pp.31-37
• /
• 2016

스마트 팩토리는 시시각각 변화하는 생산현장의 생산정보 4M1E(Man, Machine, Material, Method, Energy)생산자원을 실시간으로 통합하여 생산 관리를 무대기시간, 무재고, 무고장, 무불량일 발생할 수 있는 핵심성과지표 (KPI: Key Performance Indication)를 통하여 생산현장을 연속개선을 추진하는 것이 핵심이다. 본고에서는 스마트 제조업에 필요한 IT융합 국제표준화 동향으로 사이버 보안기술, Object Process Methodology기반 생산자원 통합기술, 실시간 이벤트기반 구조화 기술, 공통 생산정보화 플랫폼 서비스기술, 생산정보화 표준기능 및 국제표준동향과 한국형 중소제조업 스마트공장 적용 참조 모델에 대하여 알아본다.

• Review of KIISC
• /
• v.17 no.4
• /
• pp.34-41
• /
• 2007

한국정보보호진흥원이 정보통신망이용촉진및정보보호등에관한법률 제47조에 근거를 두고 시행하고 있는 정보보호관리체계(ISMS) 인증제도는 2002년 제도가 시행된 이후 현재까지 44개 기업이 인증을 취득하였다. 본 고에서는 그동안 인증취득기관의 정보보호관리체계(ISMS) 인증 심사과정에서 지적된 결함사례를 분석함으로써, 국내 중소, 대기업들이 정보보호관리체계를 수립하여 운영하는 과정에서 공통적으로 나타나는 결함사항을 정리하고, 향후 기업들이 정보보호관리체계를 수립하는 과정에서 중점적으로 고려해야 할 사항들이 무엇인지 고찰하고자 한다.

• Proceedings of the Korean Society for Information Management Conference
• /
• 1995.08a
• /
• pp.125-128
• /
• 1995

CD-ROM을 이용하여 전문도서관의 정기간행물을 평가할 목적으로 Current Contents : Life Science의 44개 SDI 검색결과와 Biotechnology 및 Biochemistry ＆ Biophysics Citation Index 에서 생명공학연구소 논문 151편의 참고문헌을 대상으로 자관 소장자료와 비소장자료로 구분하여 순위표를 만들었다. 이 순위표를 가지고 정기간행물의 자관 소장확률, 예산 증감시 정기간행물의 신규구독 및 구독중단 우선순위, 두 CD-ROM의 공통 소장/비소장 정기간행물을 조사하였다. 연구결과 생명공학연구소에 유용한 생산적인 비소장 정기간행물과 비생산적인 소장 정기간행물을 식별할 수 있었다. 이 자료는 예산 증감시 정기간행물 구입정책에 반영하면 새로운 장서구성 정책의 기초자료로 활용될 수 있다.

• Korean Journal of Food Science and Technology
• /
• v.31 no.4
• /
• pp.887-893
• /
• 1999

This study was conducted to investigate flavor components of sigumjang meju and barley bran. Among 52 kinds of flavor components identified in barley bran, the content of hexanal was the most followed by butanoic acid, 2-pentylfuran and hexanoic acid. Among 66 kinds of flavor components identified in 12 sigumjang mejus, the contents of 2-furancarboxaldehyde, 1-(3-methoxyphenyl)-ethanone and tetramethylpyrazine were more than those of any other components. Twenty two kinds of flavor components were detected in both barley bran and sigumjang meju. The contents of butanoic acid, hexanal and 2-pentylfuran were higher in barley bran than sigumjang meju. The contents of 2-furancarboxaldehyde, 1-(3-methoxyphenyl)-ethanone and tetramethylpyrazine were higher in sigumjang meju than barley bran. Thirty kinds of volatile components were detected only in barley bran and 44 kinds were detected only in sigumjang meju.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.20 no.6
• /
• pp.511-520
• /
• 2000

Ultrasonic pulse echo method comes to be difficult to apply to the multi-layered structure with very thin layer, because the echoes from the top and the bottom of the layer are superimposed. We can easily meet this problem when the silicon chip layer in the semiconductor is inspected by a SAM equipment using fairly low frequency lower than 20MHz by which severe attenuation in the epoxy mold compound of packaging material can be overcome. Conventionally, deconvolution technique has been used for the decomposition of superimposed UT signals, however it has disabilities when the waveform of the transmitted signal is distorted according to the propagation. In this paper, the wavelet transform based deconvolution(WTBD) technique is proposed as a new signal processing method that can decompose the superimposed echo signals with superior performances compared to the conventional deconvolution technique. WTBD method uses the wavelet transform in the pre-stage of deconvolution to extract out the common waveform from the transmitted and received signal with distortion. Performances of the proposed method we shown by through computer simulations using model signal with noise and we demonstrated by through experiments for the fabricated semiconductor sample with partial delamination at the top of silicon chip layer.

• Progress in Superconductivity
• /
• v.13 no.1
• /
• pp.34-39
• /
• 2011

We have performed measurements of the local magnetic field distribution of YBCO coated conductors using Low-temperature Scanning Hall Probe Microscopy (LT-SHPM). Distribution of stray magnetic field of various types of YBCO coated conductors in the superconducting state was measured in presence of external magnetic fields. We analyzed one dimensional and two dimensional local current distribution using inversion technique from the magnetic field distribution.