• Title/Summary/Keyword: the 2000s

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Changes Over Time in the Community Structure and Spatial Distribution of Forest Vegetation on Mt. Yeompo, Ulsan City, South Korea (염포산 산림식생의 군락 구조 및 공간 분포의 경시적 변화)

  • Oh, Jeong-Hak;Kim, Jun-Soo;Cho, Hyun-Je
    • Journal of Korean Society of Forest Science
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    • v.109 no.2
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    • pp.145-156
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    • 2020
  • In 2000 and 2018, phytosociological surveys were carried out in the forest vegetation of Mt. Yeompo, a representative isolated urban forest in Ulsan city. The trends of change in forest structure, composition, and spatial distribution were compared between years. Total percent coverage per 100 squaremeters of forest vegetation was similar, but natural vegetation showed a 9% increase. The importance of constituent species changed slightly. Specifically, Lindera erythrocarpa and Styrax japonicus showed very high growth rates of 835% and 269%, respectively. Species richness (S) and diversity (H') decreased by about 22% and 8%, respectively. Both S and H' showed slightly higher rates of decrease in artificial compared with natural vegetation. The constituent species life form spectrums were the same in 2000 and 2018 as 'MM-R5-D4-e'. The similarity (Jaccard coefficient) in the species composition of the forest vegetation was almost homogeneous at approximately 75%. The number of indicator species decreased from 16 species in 2000 to 7 species in 2018. This decrease was mostly due to a decline in herbaceous plants, such as Hemicryptophytes, Geophytes, and Therophytes, which are sensitive to disturbances. The spatial distribution of forest vegetation did not change significantly. The number of forest landscape elements (patches) increased by approximately 25% from 537 in 2000 to 721 in 2018, while the average size decreased by about 20% from 1.28 ha in 2000 to 1.03 ha in 2018.

Transformation and Future Prospect in the U.S. Census: Focusing on 2000 Census Experience and 2010 Census Plans (미국 센서스의 변화와 향후 전망: 2000년의 경험과 2010년의 계획을 중심으로)

  • Jun, Kwang-Hee
    • Korea journal of population studies
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    • v.31 no.2
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    • pp.101-132
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    • 2008
  • This paper discusses transformation of the US population census since 1990 and its future prospects by mentioning the 2000 census experience and the 2010 census plans. First, it examines the recommendations written for the 2000 census by the Committee on National Statistics, National Research Council, such as introduction of statistical estimation, response rate improvement, long form improvement, adjustment in differential undercount by race/ethnicity, alternative census methods, collection of small-area statistics in non-census years, and census frame enhancement, and describes how the US Supreme Court decision of 1998 led the Census Bureau to fail in conducting the US version of One Number Census which uses statistical estimation by matching actual enumerations from the Census main survey and post-enumeration survey. Second, it examines one key element of the 2010 U. S. census, say, the separation of long form from short form and describes the main features of American Community Survey, a rolling census which replaces long-form component of the traditional US "Decennial Census" Another element is MAF/TIGER Enhancement Program which aims to improve enumeration accuracy in the traditional short-form census and help the Census Bureau introduce a mobile computer system as part of high-tech census operation. In this paper, it is pointed out that the separation of long form from short form is not an accidental one which results from the US Supreme Court decision, but the Census Bureau at this time in 2008 worries about the accuracy of enumeration because it has failed to develop a mobile computer system and will have to canvass 115 million households by paper and pencil by hiring 600 thousand temporary census workers.

Self-Diagnostic Signal Monitoring System of KWP2000 Vehicle ECU using Bluetooth

  • Choi, Kwang-Hun;Lee, Hyun-Ho;Lee, Young-Choon;Kwon, Tae-Kyu;Lee, Seong-Cheol
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.132-137
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    • 2004
  • On-Board Diagnostic(OBD) systems are in most cars and light trucks on the load today. During the 1970's and early 1980's manufacturers started using electronic means to control engine functions and diagnose engine problems. The CARB's diagnostic requirements to meet EPA emission standards have been designated as OBD with a goal of monitoring all of the emissions-related components, as well as the chassis, body, accessory devices and the diagnostic control network of the vehicle for proper operation. In this paper, we present a remote measurement system for the wireless monitoring of diagnosis signal and sensors output signals of ECU adopted KWP2000, united the OBD communication protocol, on OBD-compliant vehicle using the wirless communication technique of Bluetooth. In order to measure the ECU signals, the interface circuit is designed to communicate ECU and designed terminal wirelessly according to the ISO, SAE regulation of communication protocol standard. A microprocessor S3C3410X is used for communicating ECU signals. The embedded system's software is programmed to measure the ECU signals using the ARM compiler and ANCI C based on MicroC/OS kernel to communicate between bluetooth modules using bluetooth stack. The diagnostic system is developed using Visual C++ MFC and protocol stack of bluetooth for Windows environment. The self-diagnosis and sensor output signals of ECU is able to monitor using PC with bluetooth board connected in serial port of PC. The algorithms for measuring the ECU sensor output and self-diagnostic signals are verified to monitor ECU state. At the same time, the information to fix the vehicle's problem can be shown on the developed monitoring software. The possibility for remote measurement of self-diagnosis and sensor signals of ECU adopted KWP2000 in embedded system verified through the developed systems and algorithms.

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Empirical Studies of Testing Method for the Software Reliability Measurement (소프트웨어 신뢰도 정량화를 위한 검증 방법 연구)

  • Lss, J.K.;Shin, S.G.;Nam, S.S.
    • Electronics and Telecommunications Trends
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    • v.15 no.3 s.63
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    • pp.42-49
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    • 2000
  • 소프트웨어 검증에 사용되는 신뢰도 평가를 위한 기초 고장데이터를 수집하는 시스템 시험 방법과 소프트웨어 종합화에 고려되어야 할 사항들에 대해 제안한다. 그 외에 ATM 교환시스템 개발에서 얻은 경험을 정리하여 차세대 시스템 개발의 소프트웨어 품질 향상과 신뢰도 평가에 활용되도록 하였다.

Micrometeorological measurements of VOC fluxes from Nan-Ji-Do landfill area during Spring 2000 (미기상학적 기법을 이용한 난지도 매립지에서 VOCs의 Air/Soil 교환량 측정)

  • 김민영;김기현;이강웅
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2000.11a
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    • pp.76-77
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    • 2000
  • 최근 들어 대도시와 그 주변지역을 중심으로 빈번하게 발생하는 광화학적 오염에 VOCs가 기여하는 바가 크다는 것은 주지의 사실이다. VOCs가 이와 같은 국지적인 광화학적 오염에 지대한 영향을 줄뿐만 아니라 지역 규모에서도 대기 중의 화학적인 조성과 산화력을 결정하고 있어서 이들의 발생, 화학적 변환, 소멸에 따른 기작과 동태를 규명하는 것이 대기 화학에서 중요한 부분으로 생각되고 있다. (중략)

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Fertility Decline in South Korea: Forty Years of Policy-Behavior Dialogue (한국의 출산력 감소: 40년 동안의 정책과 출산행위간의 대화)

  • Choe, Min-Ja;Park, Kyung-Ae
    • Korea journal of population studies
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    • v.29 no.2
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    • pp.1-26
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    • 2006
  • This paper examines the interplay among changes in socioeconomic conditions, population policies, and fertility decline during $1960{\sim}2000$ in South Korea. Period-parity-progression-ratios (PPPR) are calculated using 2% samples of Population Census with the implied distribution of completed family size. The total fertility rate based on PPPR declined from 5.21 in 1960 to 2.76 in 1980, and 1.69 in 2000. The family planning programs were successful in meeting the needs of families that wanted to prevent further childbearing after having achieved the desired family size during $1960{\sim}1970$. The 1980s mark two important landmarks: achievement of replacement fertility and emergence of high sex ratio at birth. In the 1990s the "quality and welfare" approach was emphasized. In 2000s, South Korea's fertility is one of the lowest in the world. In response to this, in 2005, the Government adopted a new population policy with the goal of increasing the total fertility level to 1.6 by 2010. The results of this study indicate that proportion of women who would have no children at all throughout their reproductive life span increased substantially from 10% in 1995 to 16% in 2000, with a sharp increase since 1997. Thus, pro-natal programs need to address the problems associated with marriage and having the first child. Towards that, it is important that work and family life become more compatible.