• Title/Summary/Keyword: 제3공간

Search Result 901, Processing Time 0.029 seconds

Trends and Technology Ana17sis of XKMS(Xml Key Management Specification) (XKMS(Xml Key Management Specification)동향 및 기술 분석)

  • 김세영;이석래;박정환;신동일
    • Proceedings of the Korean Information Science Society Conference
    • /
    • 2001.10a
    • /
    • pp.772-774
    • /
    • 2001
  • 최근 XML(eXtensible Markup Language)이 인터넷 전자 상거래와 데이터 전송 및 검색 부문에서 광범위하게 이용됨에 따라, XML 문서에 대한 보안과 표준화 문제가 대두되고 있다. XML을 이용한 각종 데이터 및 문서는 웹 상에 존재하게 되며, 가상공간에서 문서적 처리는 제 3자에 의해 위조나 변경이 가능하다. 이에 데이터 및 문서를 보호하는 일은 현재 필수적인 사안이며, XML 문서 보안에 대한 연구 개발 또한 활발히 진행되고 있다. 최근 Microsoft와 Verisign, Webmethods등 3개사는 XML기반 차세대 PKI(Public Key Infrastructure)기술인 XKMS(Xml Key Management Specification)를 개발하였으며, XKMS 표준화 작업에 휴렛패커드(HP), 불티모어, IBM, 퓨어에지솔루션스, 로이터 등이 참여하고 있다. 이에 본 논문에서는 XKMS의 표준화를 진행중인 표준화 단체의 XML 보안동향을 파악하고, XKMS의 내부 구조 및 전반적인 기술을 분석한다.

  • PDF

Numerical Simulations for Design of a Liquid Rocket Engine (액체 로켓엔진 설계에서의 유동해석)

  • 김영목;채연석
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 1995.11a
    • /
    • pp.87-96
    • /
    • 1995
  • 인공위성의 궤도진입에 사용되는 액체추진제 로켓엔진의 개발에서 분사기 설계를 적절히 수정, 보완 할 목적으로 수행된 핵심부품별 유동해석의 내용이 기술되었다. 단일 격자계를 구성하기 어려운 복잡한 형상의 분사기 유동장에 대한 격자계 구성을 용이하게 하고, 3차원의 점성 유동해석을 컴퓨터 기억 용량에 제한없이 수행하기 위한 다중블럭 격자기법이 사용되었다. 분사기의 내부유동은 3차원 비압축성 Navier-Stokes 방정식으로 pseudocompressibility 방법을 이용하여 수치모사되었다. 정상상태의 해는 근사 인자분해에 의한 ADI 기법으로 계산되고, 공간미분항에 대해 nonstaggered 격자계에서 2차 중앙차분을 사용하며 수치해의 안정성을 위해 인공점성항을 추가하였다. 난류계산을 위해 Baldwin- Lomax의 대수적 난류모델에 다수의 벽면효과를 고려하였다. 해석결과는 분사기의 성능에 영향을 미칠 수 있는 유동조건에 따라 분석되었다.

  • PDF

Response of Structural, Biochemical, and Physiological Vegetation Indices Measured from Field-Spectrometer and Multi-Spectral Camera Under Crop Stress Caused by Herbicide (마늘의 제초제 약해에 대한 구조적, 생화학적, 생리적 계열 식생지수 반응: 지상분광계 및 다중분광카메라를 활용하여)

  • Ryu, Jae-Hyun;Moon, Hyun-Dong;Cho, Jaeil;Lee, Kyung-do;Ahn, Ho-yong;So, Kyu-ho;Na, Sang-il
    • Korean Journal of Remote Sensing
    • /
    • v.37 no.6_1
    • /
    • pp.1559-1572
    • /
    • 2021
  • The response of vegetation under the crop stress condition was evaluated using structural, biochemical, and physiological vegetation indices based on unmanned aerial vehicle (UAV) images and field-spectrometer data. A high concentration of herbicide was sprayed at the different growth stages of garlic to process crop stress, the above ground dry matter of garlic at experimental area (EA) decreased about 46.2~84.5% compared to that at control area. The structural vegetation indices clearly responded to these crop damages. Spectral reflectance at near-infrared wavelength consistently decreased at EA. Most biochemical vegetation indices reflected the crop stress conditions, but the meaning of physiological vegetation indices is not clear due to the effect of vinyl mulching. The difference of the decreasing ratio of vegetation indices after the herbicide spray was 2.3% averagely in the case of structural vegetation indices and 1.3~4.1% in the case of normalization-based vegetation indices. These results meant that appropriate vegetation indices should be utilized depending on the types of crop stress and the cultivation environment and the normalization-based vegetation indices measured from the different spatial scale has the minimized difference.

Studies on the Assumption of the Locations and Formational Characteristics in Yigye-gugok, Mt. Bukhansan (북한산 이계구곡(耳溪九曲)의 위치비정과 집경(集景) 특성)

  • Jung, Woo-Jin;Rho, Jae-Hyun;Lee, Hee-Young
    • Journal of the Korean Institute of Traditional Landscape Architecture
    • /
    • v.35 no.3
    • /
    • pp.41-66
    • /
    • 2017
  • The purpose of this research is to empirically trace the junctures of Yigye-gugok managed by Gwan-am Hong Gyeong-mo, a grandson of Yigye Hong Yang-ho who originally designed Yigye-gugok, while reviewing the features of the forms and patterns of gugok. The results of the research are as follows. 1. Ui-dong was part of the domain of the capital during the Chosun dynasty, which also is located in the city of Seoul as a matter of administrative zone. Likewisely, Yigye-gugok is taken as a special meaning for it was one and only gugok. Starting with Mangyeong Waterfall as the $1^{st}$ gok, Yigye follows through the $2^{nd}$ gok of Jeokchwibyeong Rock, the $3^{rd}$ gok of Chanunbong Peak, the $4^{th}$ gok of Jinuigang Rock, the $5^{th}$ gok of Okkyeongdae Rock, the $6^{th}$ gok of Wolyeongdam Pond, the $7^{th}$ gok of Tagyeongam Rock, the $8^{th}$ gok of Myeongoktan Stream, and the $9^{th}$ gok of Jaeganjeong Pavilion. Of these, Mangyeong Waterfall, Chanunbong Peak, and Okkyeongdae Rock are distinct for their locations in as much as their features, while estimated locations for Jinuigang Rock, Wolyeongdam Pond, Myeongoktan Stream, and Jaeganjeong Pavilion were discovered. However, Jeokchwibyeong Rock and Tagyeongam Rock demonstrated multiple locations in close resemblance to documentary literatures within secretive proximity, whereas geography, scenery, and sighted objects were considered to evaluate the 1st estimated location. Through these endeavored, it was possible to identify the shipping routes and structures for the total distance of 2.1km running from the $1^{st}$ gok to the $9^{th}$ gok, which nears Gwanam's description of 5ri(里), or approximately 1.96km for gugok. 2. Set towards the end of the $18^{th}$ century, Yigye-gugok originated from a series of work shaping the space of Hong Yang-ho's tomb into a space for the family. Comparing Yigye-gugok to other gugoks, numerous differences are apparent from beyond the rather more general format such as adjoining the $8^{th}$ gok while paving through the lower directions from the upper directions of the water. This gives rises to the interpretation such that Yigye-gugok was positioned to separate the doman of the family from those of the other families in power, thereby taking over Ui-dong. Yet, the aspect of the possession of the space lends itself to the determination that the location positioned at the $8^{th}$ gok above Mangyeongpok Waterfall representing Wooyi-dong was a consequence of the centrifugal space creation efforts. 3. While writings and poetic works were manufactured in such large quantities in Yigye-gugok whose products of setters and managers seemed intended towards gugok-do and letters carved on the rocks among others, there is yet a tremendous lack of visual media in the same respect. 'Yigye-gugok Daejacheop' Specimens of Handwriting offers the traces of Gwanam's attempts to engrave gakja at the food of Yigye-gugok. This research was able to ascertain that 'Yigye-gugok Daejacheop' Specimens of Handwriting was a product of Hong Yang-ho's collections maintained under the auspices of the National Central Museum, which are renowned for Song Shi-yeol's penmanship.

A Study on GIS Implementation and Maintenance Model in Local Governments (지자체 GIS 추진 및 운영모델에 관한 연구)

  • Koh, Kwang-Chul;Kim, Eun-Hyung
    • Journal of Korea Spatial Information System Society
    • /
    • v.4 no.2 s.8
    • /
    • pp.5-22
    • /
    • 2002
  • The considerable budgets for the 2nd-phase NGIS projects are allocated to the projects for developments of the GIS applications. Especially, the 78 local governments are major users of GIS application systems. In spite of GIS necessity in local government, whether a GIS is 'good' or bad, depends on its implementation and operation. How to implement GIS in effective wav and how to measure GIS effect for justifying GIS funding can be major concerns. Because it takes minimum 3-4 years to equal the costs and benefits of GIS, the long-terms implementation strategies for GIS project in local government are required. In order to establish a proper implementation model for the GIS application projects and to promote activities in the projects, this study considers several problems in accordance with the phases of GIS evolution and solutions of these problems. Based an the GIS auditing and consulting experience in local governments, this study constructs a GIS implementation and maintenance model in long and comprehensive perspective. This model can be a key to affective and realistic implementation for the future GIS projects.

  • PDF

Reviewing geology and groundwater change in a fault zone caused by tunnel construction (터널공사에 의한 단층대 지역의 지질 및 지하수 변화 분석)

  • Jeon, Hang-Tak;Hamm, Se-Yeong;Lee, Chung-Mo;Lim, Woo-Ri;Yun, Sul-Min
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2017.05a
    • /
    • pp.466-466
    • /
    • 2017
  • 지하공간의 개발과 지하공간의 굴착으로 인한 지표수 및 지하수 시스템의 변화나 굴착면 주위의 지하수 유동 체계의 변화는 터널내로의 지하수 유입, 지표수 고갈을 가져온다. 또한 터널 상부의 지반에서 현지응력의 변화로 인한 지하수 유출은 지표침하, 하천수 및 계곡수 고갈을 발생시킬 수 있다. 그러나, 터널설계 시 비용 및 시간, 현장의 진입조건 등의 제약으로 상세한 지반조사의 실시가 이루어지지 않을 때가 있다. 또한, 터널 공사가 진행되는 중에는 공사기간과 공사비 때문에 별도의 지반조사를 하지 않는다. 그 대신에 터널 막장에서 실시하는 Face Mapping을 토대로 공사를 진행하며, 대규모 위험요소가 발견되지 않는 이상 별도의 비용과 시간을 투입하여 추가 지질 및 지반 조사를 실시하는 경우는 매우 드물다. 연구지역의 지질은 경상분지내 백악기 하양층군의 퇴적암류, 이를 관입/분출한 불국사화강암류 및 제3기 화산암류, 전기 에오세 연일층군에 대비되는 퇴적암류로 구성되어 있다. 이들을 피복하는 제4기 충적 퇴적층은 주로 단층곡과 동측 지괴의 선상지 및 하천을 따라 분포한다. 연구지역에는 폭 100 m 이상의 대규모 단층대가 발달하였으며 제4기 단층운동으로 인한 단층파쇄대가 존재한다. 퇴적암 분포지역에서는 반복층서가 관찰되며 소규모 단층, 단열, 변형띠 등이 연속적으로 발달해 있다. 본 연구에서는 터널공사에 의한 지하수 변화를 확인하기 위하여 현장추적자 시험과 수질분석 및 지하수 모델링을 실시하였다. 현장 수질 분석에 의한 지표수와 지하수 간의 수질의 차이를 보면, 알칼리도를 제외한 대부분의 수질 항목이 서로 유사성을 보인다. 전기전도도(EC), TDS, 알칼리도의 경우 지표수의 수원지에서 터널 내부로 유입이 일어나고 있다. 이는 터널 공사의 영향으로 판단되며, 현장에서 실시한 추적자 시험에서는 추적자의 이동 시간이 매우 빨라 지표 수원지로부터 지표수가 터널내부로 빠른 속도(10시간 이내)로 유입된다고 판단된다. 지하수 모델링 결과, 정상류 상태에서는 지하수가 북동쪽의 높은 고도에서 서남쪽의 낮은 고도로 흐르는 것으로 확인되며, 가뭄시에도 지하수 함양으로 지하수가 고갈되지는 않는 것으로 나타났다. 부정류 상태 모델링 결과, 일일 평균 $32.49m^3$의 지하수가 터널 내부로 유입되는 것으로 산정되었다. 이 양은 터널 내부뿐만 아니라 터널 공사 현장 주위로도 지하수 유출이 일어나고 있음을 지시한다.

  • PDF

Evaluation of applicability of xanthan gum as eco-friendly additive for EPB shield TBM soil conditioning (친환경 첨가제로서 잔탄검의 토압식 쉴드 TBM 쏘일 컨디셔닝 적용성 평가)

  • Suhyeong Lee;Hangseok Choi;Kibeom Kwon;Byeonghyun Hwang
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.26 no.3
    • /
    • pp.209-222
    • /
    • 2024
  • The Earth Pressure Balance (EPB) shield Tunnel Boring Machine (TBM) is widely used for underground tunnel construction for its advantages, such as eliminating the need for additional facilities compared to the slurry shield TBM, which requires Slurry Treatment Plant (STP). During EPB shield TBM excavation, a soil conditioning technique is employed to enhance the physical properties of the excavated soil by injecting additives, thus broadening the range of applicable ground conditions to EPB shield TBMs. This study explored the use of xanthan gum, a type of biopolymer, as an alternative to the commonly used polymer additive. Biopolymers, derived from biological sources, are fully biodegradable. In contrast to traditional polymers such as polyacrylic acid, which contain environmentally harmful components, xanthan gum is gaining attention as an eco-friendly material due to its minimal toxicity and environmental impact. Test conditions with similar workability were established through slump tests, and the rheological characteristics were assessed using a laboratory pressurized vane shear test apparatus. The experiments demonstrated that, despite exhibiting similar workability, the peak strength in the flow curve decreased with increasing the content of xanthan gum. Consequently, a correlation between the xanthan gum content and peak strength was established. Replacing the traditional polymers with xanthan gum could enable stable EPB shield TBM operation by reducing equipment load, in addition to offering environmental benefits.

MR Study of Wate Exchange and Cell Membrane Permeability in Rat Liver Cells Using a Tissue-Specific MR Contrast Agent (조직 특성 MR 조영제를 이용한 쥐의 간세포막의 물분자 교환 및 투과율의 MR 측정기법)

  • Yongmin Chang
    • Investigative Magnetic Resonance Imaging
    • /
    • v.2 no.1
    • /
    • pp.73-82
    • /
    • 1998
  • Purpose : A precise NMR technique for measuring the rate of water exchange and cell membrane permeability across the hepatocyte membrane using liver-specific MR contrast agent is described. Materials and Methods : The rat hepatocytes isolated by perfusion of the livers were used for the NMR measurements. All experiments were performed on an IBM field cycling relaxometer operating from 0.02MHz to 60 MHz proton Larmor frequency. spin-echo pulse sequence was empolyed to measure spin-lattice relaxation time, T1. The continuous distribution analysis of water proton T1 data from rat hepatocytes containing low concentrations of the liver specific contrast agent, Gd-EOB-DTPA, modeled by a general two compartment exchange model. Results : The mean residence time of water molecule inside the hepatocyte was approximately 250 msec. The lower limit for the permeability of the hepatocyte membrane was $(1.3{\pm}0.1){\;}{\times}{\;}10^{-3}cm/sec$. The CONTIN analysis, which seeks the natural distribution of relaxation times, reveals direct evidence of the effect of diffusive exchange. the diffusive water exchange is not small in the intracellular space in the case of hepatocytes. Conclusions : Gd-EOB-DTPA, when combined with continuous distribution analysis, provides a robust method to study water exchange and membrane permeability in hepatocytes. Water exchange in hepatocyte is much slower thatn that in red blood cells. Therefore, tissue-specific contrast agent may be used as a functional agent to give physiological information such as cell membrane permeability.

  • PDF

Clinical Management and Short-term Prognosis of Molar-Incisor Malformation Affected Patients: Case Reports (대구치-절치 형태이상 환자의 임상적 치료 및 단기 예후: 증례 보고)

  • Kim, Hyojin;Lim, Sumin;Kim, JinYoung
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.49 no.1
    • /
    • pp.121-130
    • /
    • 2022
  • Molar-incisor malformation (MIM) is a newly reported dental anomaly with molar root deformity and incisor crown defects. MIM-affected teeth may cause severe pain with no apparent tooth caries. Since the affected molars clinically appear normal, radiographs are recommended for accurate diagnosis on the first visit. Since MIM-affected patients are in mixed dentition, timely and appropriate interventions are needed to avoid unnecessary pain and complicated clinical issues. This report was written to describe two patients who had MIM in early mixed dentition and report their 2-year follow-ups.

Status of Policy Implementation and Review of Institution on Multi-functionalization of School Facilities (학교시설 복합화 제도 검토 및 정책 현황)

  • Byun, Kyeong-hwa
    • The Journal of Sustainable Design and Educational Environment Research
    • /
    • v.22 no.3
    • /
    • pp.1-13
    • /
    • 2023
  • This study aims to analyze related laws and institutions and identify research trends and the policy implementation status of the multifunctionalization of school facilities. Beginning in 2001 at Seoul Geumho Elementary School, the enactment of the "Act On The Establishment, Operation And Management Of Multifunction School Facilities" in 2020, was elucidated through the concept and spectrum of the multifunctionalization of school facilities. The relevant research mainly focuses on elementary schools, elderly facilities, and space planning. The Living SOC Project in 2019 acted as a trigger in promoting the multifunctionalization of school facilities as a central government policy. In 2023, the Ministry of Education announced measures and guidelines for establishing the multifunctionalization of school facilities by conducting the project with respect to the "Nulbum School" policy.