• 제목/요약/키워드: Digital numbers

검색결과 308건 처리시간 0.041초

An Approach to the Spectral Signature Analysis and Supervised Classification for Forest Damages - An Assessment of Low Altitued Airborne MSS Data -

  • Kim, Choen
    • 대한원격탐사학회지
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    • 제7권2호
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    • pp.149-163
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    • 1991
  • This paper discusses the capabilities of airborne remotely sensed data to detect and classify forest damades. In this work the AMS (Aircraft Multiband Scanner) was used to obtain digital imagery at 300m altitude for forest damage inventory in the Black Forest of Germany. MSS(Multispectral Scanner) digital numbers were converted to spectral emittance and radiance values in 8 spectral bands from the visible to the thermal infrared and submitted to a maximum-likelihood classification for : (1) tree species ; and. (2) damage classes. As expected, the resulted, the results of MSS data with high spatial resolution 0.75m$\times$0.75m enabled the detection and identification of single trees with different damages and were nearly equivalent to the truth information of ground checked data.

최소 권한 계정 분리 모델을 이용한 데이터베이스 엑세스 제어 연구 (A Study on Database Access Control using Least-Privilege Account Separation Model)

  • 장영수
    • 디지털산업정보학회논문지
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    • 제15권3호
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    • pp.101-109
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    • 2019
  • In addition to enabling access, database accounts play a protective role by defending the database from external attacks. However, because only a single account is used in the database, the account becomes the subject of vulnerability attacks. This common practice is due to the lack of database support, large numbers of users, and row-based database permissions. Therefore if the logic of the application is wrong or vulnerable, there is a risk of exposing the entire database. In this paper, we propose a Least-Privilege Account Separation Model (LPASM) that serves as an information guardian to protect the database from attacks. We separate database accounts depending on the role of application services. This model can protect the database from malicious attacks and prevent damage caused by privilege escalation by an attacker. We classify the account control policies into four categories and propose detailed roles and operating plans for each account.

Optimal filter materials for protist quantification via droplet digital PCR

  • Juhee Min;Kwang Young Kim
    • ALGAE
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    • 제39권1호
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    • pp.51-56
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    • 2024
  • The use of droplet digital polymerase chain reaction (ddPCR) has greatly improved the quantification of harmful protists, outperforming traditional methods like quantitative PCR. Notably, ddPCR provides enhanced consistency and reproducibility at it resists PCR inhibitors commonly found in environmental DNA samples. This study aimed to determine the most effective filter material for ddPCR protocols by assessing the reproducibility of species-specific gene copy numbers and filtration time across six filter types: cellulose acetate (CA), mixed cellulose ester (MCE), nylon (NY), polycarbonate (PC), polyethersulfone (PES), and polyvinylidene fluoride (PVDF). The study used two species of Chattonella marina complexes as a case study. Filtration rates were slower for NY, PC, and PVDF filters. Moreover, MCE, NY, PES, and PVDF yielded lower DNA amounts than other filters. Importantly, the CA filter exhibited the lowest variance (38-39%) and the highest determination coefficients (R2 = 0.92-0.96), indicating superior performance. These findings suggest that the CA filter is the most suitable for ddPCR quantification of marine protists, offering quick filtration and reliable reproducibility.

지적장애인 대상의 성교육 프로그램 현황과 과제 : 디지털 교육콘텐츠를 중심으로 (An Exploratory Study on Digital Contents-based Life-long Sex Education Program for Persons with Mental Retardation)

  • 박원희;최연숙;박성택
    • 디지털융복합연구
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    • 제10권6호
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    • pp.349-359
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    • 2012
  • 본 연구에서는 현재 우리나라의 지적장애인 대상의 디지털 성교육 콘텐츠 프로그램과 현황을 살펴보고, 이에 따른 디지털 성교육 콘텐츠 구성에 대한 연령별 제안과 피셔의 성교육에 관한 정보 동기 행동 스킬 모형을 인적자원 개발에서 흔히 논의되는 역량(competency)이라는 개념의 모형을 적용 확장하여 성적역량(sexual competency) 이라는 목표 하에서 모형을 제시해 보았다. 또한 이러한 모형과 현황조사를 바탕으로 적절한 디지털 성교육 프로그램 개발을 위한 과제를 제시해 보았다.

3D 애니메이션 데이터 구성요소 및 분류방식 (Component and Classification Method on 3d Animation Data)

  • 김현조;김계원
    • 한국콘텐츠학회논문지
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    • 제8권12호
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    • pp.118-130
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    • 2008
  • 오늘날 IT 기술력의 발달로 인하여 디지털 코드인 0,1숫자들이 각종 미디어의 소통을 담당하고 있다고 해도 과언이 아닐지도 모른다. 시대적인 흐름에 따라 뉴미디어가 등장하면서 다양한 콘텐츠, 미디어의 등장 및 기존 콘텐츠 및 미디어들 간의 컨버젼스(Convergence)들이 이루 졌으며, 데이터간의 통합 및 경계의 벽이 허울어지는 속도가 급속도로 이루어지고 있다. 이러한 디지털 환경 속에서 새롭게 만들어지고, 사라지는 수많은 데이터의 양들도 디지털 기술력의 발달속도만큼 빠르게 변화되어지고 있다. 따라서 본 논문에서는 3D 애니메이션 리소스에 대한 데이터 관리 및 재활용 그리고 저작권 확보를 위한 효율적인 데이터 구성 요소에 대한 분류 및 방식에 대한 연구를 하는데 그 목적이다.

디지털 홀로그래픽 입자유속계를 이용한 미세곡관 내부유동 측정 (Measurement of Flow inside Curved Microtube Using a Digital Micro Holographic Particle Velocimetry)

  • 김석;이상준
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2007년도 추계학술대회
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    • pp.116-118
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    • 2007
  • Three-dimensional (3D) velocity field information of a laminar flow in a curved micro tube of circular cross-section has been measured using a digital micro holographic particle tracking velocimetry (HPTV). The temporal evolution of instantaneous velocity field of a water flow in a curved micro tube of $100\;{\mu}\;m$ and $300\;{\mu}\;m$ in inner diameter was obtained. The 3D mean velocity field distribution was obtained quantitatively by statistical-averaging of instantaneous velocity fields. At low Dean number (De), a secondary flow was not generated in the curved tube. With increasing Dean number, the secondary flow constituted of two large-scale counter-rotating vortices was formed due to enhanced centrifugal force. To reveal the flow characteristics of high Dean numbers, trajectories of fluid particles were evaluated experimentally from the 3D velocity fields data measured by the HPTV technique. The present experimental results, especially the 3D particle trajectories, would be helpful to design and to understand the mixing phenomena in 3D curved passages of various curved micro-tubes or micro-channels.

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DCT and Homomorphic Encryption based Watermarking Scheme in Buyer-seller Watermarking Protocol

  • Seong, Teak-Young;Kwon, Ki-Chang;Lee, Suk-Hwan;Moon, Kwang-Seok;Kwon, Ki-Ryong
    • 한국멀티미디어학회논문지
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    • 제17권12호
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    • pp.1402-1411
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    • 2014
  • Buyer-seller watermarking protocol is defined as the practice of imperceptible altering a digital content to embed a message using watermarking in the encryption domain. This protocol is acknowledged as one kind of copyright protection techniques in electronic commerce. Buyer-seller watermarking protocol is fundamentally based on public-key cryptosystem that is operating using the algebraic property of an integer. However, in general usage, digital contents which are handled in watermarking scheme mostly exist as real numbers in frequency domain through DCT, DFT, DWT, etc. Therefore, in order to use the watermarking scheme in a cryptographic protocol, digital contents that exist as real number must be transformed into integer type through preprocessing beforehand. In this paper, we presented a new watermarking scheme in an encrypted domain in an image that is based on the block-DCT framework and homomorphic encryption method for buyer-seller watermarking protocol. We applied integral-processing in order to modify the decimal layer. And we designed a direction-adaptive watermarking scheme by analyzing distribution property of the frequency coefficients in a block using JND threshold. From the experimental results, the proposed scheme was confirmed to have a good robustness and invisibility.

주민등록번호 기반의 온라인 본인확인서비스 기관 지정기준 개선방안 연구 (A Study on Improvement method of designation criteria for Personal Proofing Service Based on Resident Registration Number)

  • 김종배
    • 디지털산업정보학회논문지
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    • 제16권3호
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    • pp.13-23
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    • 2020
  • Currently, online means of replacing resident registration numbers(RRN) include I-Pin, mobile phone, credit card, MyPin, and general-purpose certificate. In order to issue alternative means based on the RRN, it must be designated through the designation review by the Korea Communications Commission(KCC) through a designation review by personal proofing agency and be subject to annual management. However, the criteria for designation and follow-up of the designation of the personal proofing agency carried out by KCC have been used in 2010 without revision, and there are problems that do not conform to the evaluation standards of various alternative means. Therefore, in this paper, we propose a method for improving the designation criteria and management system of the personal proofing service agency. The proposed method analyzes the characteristics of the alternative identification-based personal proofing service and proposes a follow-up management standard that can appropriately evaluate the analyzed characteristics and improves the designation criteria according to the emergence of new alternatives. Through the proposed method, it can be seen that it is possible to strengthen the safety of the personal proofing service based on the alternative means of RRN provided online and face-to-face and to protect the user's personal information.

디지털 비디오 방송-지상파에서 연쇄 터보 부호화의 성능분석 (Performance Analysis of Concatenated Turbo Coding Scheme over DVB-T Transmission Channel)

  • 장극;서희종
    • 한국전자통신학회논문지
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    • 제13권1호
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    • pp.69-76
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    • 2018
  • 본 논문에서는 OFDM(Orthogonal Frequency-Division Multiplexing)에서 터보코드, RS(Reed-Solomon)코드를 연구하고, DVB-T(digital terrestrial video broadcasting)에서 OFDM에 적용된 FEC(Forward Error Correct)의 성능을 분석한다. 그리고 표준 AWGN 통신로의 경우와 비교한다. 모의실험을 한 결과 반복해서 터보코드를 사용하면 성능이 현저히 개선됨을 확인할 수 있었다. 이는 컨케이트네이티드 FEC에 적절한 인터리버를 적용해서 구현가능 할 것이다.

디지틀 이동무선통신을 위한 위상일주파수 혼합 변조방식에 관한 연구 (A Study on Digital Phase-Frequency Modulation System for Mobile Radio Communications)

  • 홍현성;조성준;김원후
    • 한국통신학회논문지
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    • 제11권2호
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    • pp.122-136
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    • 1986
  • 본 논문에서는 이동 무선 통신을 위한 새로운 변조 방식인 디지털 위상-주파수 혼합 변조 시스템(digital phase-frequency hybrid modulation system, PFSK)을 제안하고, 이 신호가 m~분포 페이딩 채널을 통과할 경우의 시스템의 오율 및 중단율에 관한 일반식을 구하였다. 특히 레일리 페이딩에 대해서는 다이버시트 수신 기법을 이용하였을 경우의 시스템의 오율 및 중단율에 관한 일반식을 유도하였다. 유오된 오율식에서 반송파 전력 대 잡음 전력비(CNR), 페이딩 지수, 다이버시티 branch의 수, branch사이의 상관 계수를 파라미터로 수치 계산을 하여, PFSK 시스탐과 같이 심볼 전송을 하는 QDPSK시스템의 성능을 오율 및 중단율의 측면에서 비교 평가하였다. 해석 결과, 강한 페이딩하에서는 PFSK시스템이 QDPSK 시스템에 비해 오율 특성이 우수함을 알 수 있었고, 다이버시티 기법을 사용하므로써 시스템의 성능을 크게 개선시킬 수 있음을 알 수 있었다.

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