• 한국학교보건학회지
• /
• 제12권1호
• /
• pp.97-107
• /
• 1999

The purpose of the study was to ascertain the trends of future circumstances in primary education along with population change. These trends, which are subject to change in population and structure, have a great impact on the size and characteristics of primary school-aged children. Accordingly, it is imperative for the government to plan for future conditions involving primary education. The major findings of the study were as follows: 1. In the long-term primary school children aged 6-11, which accounted for 17.7% of the total population in 1970, will decline to 8.6% by the year 2000, 6.9% in 2020 and 6.4% in 2030. This drastic reduction in fertility rate is a direct result of pressure by the government to control population. 2. In 1996, the total number of classes in primary schools rose to 106,594. In the future, these numbers will actually decline. By 2003 the total number of classes will peak at 142,605, but until then drop off to 112,288 by 2030-a decrease of over 6,000. 3. The actual number of primary schools in 1997 totaled 5,721. This figure will reach its highest peak, 5,942, in 2003, but it is expected decrease later after declining by 1,263, it will bottom out at 4,679 in 2003. 4. The number of teachers at primary schools increased from 101,095 in 1970, 119, 064 in 1980, 136,800 in 1990 to 138,369 in 1995. Accordingly this means that the ratio of students to teaching staff changed for the better. By the year 2005, if teachers of specialty subjects (music, art, English, physical education) are assigned to every primary school with over 18 classrooms and the number of students per class is 30, it should improve educational surroundings. This is because it is expected that the population of primary school children will continue to grow until 2003 and then decrease. Thus, there is a need to maintain the number of primary school teachers between the years 2003 and 2030 so that the ratio of students to teachers will be reduced to 1/20.25. In considering factors related to migration which influence conditions of education, it is evident that changes have already begun. In the suburbs of Seoul, population shifts are causing overcrowding in classrooms. The government believes it would be inefficient to invest in education because fluctuating migration figures make it impossible. Accordingly, we have to be concerned about stabilizing the population throughout the entire country.

• 한국토양비료학회지
• /
• 제28권4호
• /
• pp.356-362
• /
• 1995

1979년 이래 유기물(有機物)을 연용(連用)한 논토양에 있어서 미생물상(微生物相)의 이절적(李節的) 변화(變化)를 구명(究明)하고자 호남지역 전북통인 논토양에 유기물(有機物)로써 무시용, 볏짚 및 퇴비를 그리고 질소수준으로써 무시용, 150kg/ha를 처리하여 표토(表土)로부터 15cm깊이토양의 미생물상(微生物相) 변화(變化)를 검토(檢討)하였다. 전세균수(全細菌數)는 수도이앙전(水稻移秧前)인 담수직후(湛水直後)부터 유수형성기(幼穗形成期)까지 점진적인 증가 후 수확기까지 감소(減少)하였으며 방선균(放線菌), 사상균(絲狀菌) 및 셀루로스분해균수(分解菌數)은 유수형성기(幼穗形成期)까지 미약한 변화를 보였으나 그 이후 수확기까지 증가(增加)하였다. 또한 대부분의 미생물수(微生物數)는 유기물과 질소의 장기혼용구(長期混用區)에서 높았으나 셀루로스분해균만은 유기물 단독시용구에서 높았다. 질소순환미생물중 암모니아 산화균수는 수확기에, 질산산화균수와 질산환원균수는 유수 형성기에 그리고 탈질균수는 분얼초기에 높았으나 암모니아 화성균수는 유기물 또는 질소(窒素)시용 여부에 따라 달랐다. 이들 미생물들은 유기물(有機物)이나 질소의 단독시용구에 비하여 유기물과 질소혼용구(窒素混用區)에서 높았으며, 특히 탈질균은 유기물(有機物)중 볏짚시용구에서 높았으나 그 외는 차이가 없었다.

• 천문학회보
• /
• 제43권2호
• /
• pp.47.1-47.1
• /
• 2018

Solar cycles are inherent to the Sun, which experiences temporal changes in its magnetic activity via the surface distribution of the solar magnetic field. This raises a fundamental question of how to derive the distribution characteristics of a solar-surface magnetic field that are responsible for individual solar cycles. We present a new approach to deriving as long-term and large-scale distribution characteristics of this quantity as was ever obtained; that is, we conducted a population ecological analysis of Wilcox Solar Observatory (WSO) Synoptic Charts which provide a more than 40-year time series of latitude-longitude maps of solar-surface magnetic fields. In this approach, solar-surface magnetic fields are assumed as hypothetical trees with magnetic polarities (magnetic trees) distributed on the Sun. Accordingly, we identified a peculiarity of cycle 23 with a longer period than an average period of 11 years; specifically we found that the negative surface magnetic field had much more clumped distributions than the positive surface magnetic field during the first one-third of this cycle, while the latter was dominant over the former. The Sun eventually spent more than one-third of cycle 23 recovering from these imbalances.

• 국제초고층학회논문집
• /
• 제13권1호
• /
• pp.33-56
• /
• 2024

This paper examines China's rapid shift from low-rise to high-rise urban development, focusing on Shanghai as a case study. It provides a detailed analysis of the rapid vertical developments over the past five decades, highlighting gradual and sudden tall building changes. The study also surveys tall building development in the ten "tallest cities" across China, including Hong Kong, Shenzhen, Guangzhou, Shanghai, Wuhan, Chongqing, Chengdu, Shenyang, Hangzhou, and Nanning, while listing the tallest ten buildings in each city. The focus is on the drivers behind these towering structures: globalization, an economic powerhouse, and finance center, urbanization and population density, architectural innovation and ambition, competition and prestige, land availability and utilization, government support and planning, and tourism. The paper critically examines the sustainability of this trend in light of new Chinese policies restricting the construction of high-rise buildings exceeding 500m and 250m in smaller cities due to safety and security concerns. This prompts a reflection on the long-term viability and implications of the predominantly high-rise trajectory in urban development.

• Imaging Science in Dentistry
• /
• 제53권1호
• /
• pp.1-9
• /
• 2023

Purpose: The aim of this study was to evaluate 3-dimensional cone-beam computed tomography (CBCT) images of alveolar bone changes in patients who underwent minimally invasive periodontal surgery-namely, the pinhole surgical technique (PST). Materials and Methods: Alveolar bone height was measured and compared on CBCT images of 254 teeth from 23 consecutive patients with Miller class I, II, or III recession who had undergone PST. No patient with active periodontal disease was selected for surgery. Two different methods were used to assess the alveolar bone changes postoperatively. In both methods, the distance between the apex of the tooth and the mid-buccal alveolar crestal bone on pre- and post-surgical CBCT studies was measured. Results: An average alveolar bone gain >0.5 mm following PST was identified using CBCT(P=0.05). None of the demographic variables, including sex, age, and time since surgery, had any significant effect on bone gain during follow-up, which ranged from 8 months to 3 years. Conclusion: PST appears to be a promising treatment modality for recession that results in stable clinical outcomes and may lead to some level of resolution on the bone level. More long-term studies must be done to evaluate the impact of this novel technique on bone remodeling and to assess sustained bone levels within a larger study population.

• 한국인구학
• /
• 제10권2호
• /
• pp.1-16
• /
• 1987

이 논문은 미국 노동시장의 재취업과정을 사건사의 실업자료를 이용하여 분석하였다. 재취업과정은 실업기간에 따라 변화하는 재취업률의 변화로 파악하였다. 분석에서는 이중노동 시장의 구조적 특성이 재취업과정에 미치는 영향을 살펴보았다. 이차노동시장은 경쟁시장이다. 경쟁시장에서 사람들은 더 나은 직장을 찾기 위해 직장을 그만두기 때문에 자발적 실업이 발생한다. 직장탐색이론에 의하면 자발적 실업에서 사람들은 실업기간이 경과하면서 자신의 의중임금을 떨어뜨림으로써 재취업률을 높이고자 한다. 이에 반하여, 일차노동시장은 장기간 고용관계로 이루어진, 경쟁적 성격이 약한 노동시장이다. 장기적 고용관계에서 실업은 경기가 좋지 않은 시기에 일시해고에 의해 비자발적으로 발생한다. 계약이론에 의하면 일시해고를 당한 사람은 원래의 직장에서 다시 부를 때까지 기다리기 때문에 재취업률은 실업기간에 관계없이 일정하다. 실증분석의 결과는 재취업과정이 이중노동시장에 의해 영향을 받는다는 사실을 보여주고 있다. 즉 일차노동시장에서 사람들은 실업을 당했을 경우, 기업에서 다시 부르기를 기다리는 성향이 강하게 나타났다. 한편 이차노동시장에서 실업을 당한 사람들의 경우, 새로운 직장을 찾는 경향이 높았다. 그러나 실업기간에 따른 재취업률의 변화는 직장탐색이론이 예측하는 수준보다 낮게 나타났다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권sup1호
• /
• pp.71-78
• /
• 2016

Printing of pictorial health warnings (PHWs) on cigarette packages became obligatory by the Vietnam Law on Prevention and Control of Tobacco Harm in May 2013. Literature from high-income countries suggests that PHWs motivate smokers to quit smoking although their long-term effects have been questioned due to reduction of impact over time. This study aimed to assess the salience of PHWs and smokers' reactions towards PHWs over time. In May 2014 and May 2015, a cross-sectional questionnaire-based household survey was administered to respectively 1,462 and 1,509 Vietnamese male smokers aged 18 to 35. The result showed that salience of the PHWs 2 years after the implementation was higher than at the point of 1 year after the implementation. The proportion of respondents who tried to avoid noting the PHWs was reduced from 35% in wave 1 to 23% in wave 2. However, "Tried to avoid looking/thinking about the PHWs" increased 1.5 times the odds of presenting quit intention compared to those respondents who did not try to avoid looking/thinking about the PHWs (OR=1.5; 95%CI: 1.2-2.0). In conclusion, avoidance regarding PHWs may not work as a barrier when aiming at a higher level of quit intention. Salience of the PHWs may increase in the period shortly after their introduction onto packs but can be expected to decrease with time. In other words, it might be advisable to change or renew PHWs after a period of implementation to maintain their beneficial effects.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권9호
• /
• pp.3957-3960
• /
• 2015

Background: Several studies have examined the relationship between oral contraceptive pill (OCP) use, abortions and breast cancer, with mixed results. Hormonal changes associated with OCP use and abortion may increase risk of breast cancer over time, but there is a lack of studies studying this association in Saudi Arabian women. Materials and Methods: We thererfore conducted a case control study in 192 women (92 as cases and 100 as controls), aged 30 to 65, and collected information on variables including examples related to study objectives and those which may confound findings. The Chi square test was used to detect associations between various factors and risk of breast cancer. Results: We found no evidence of interaction between history of abortion or frequency of abortion and breast cancer risk (Chi square=0.422, p =0.420 and 1, p =0.169) respectively. Oral contraceptives did not confer risk for breast cancer overall (OR=0.276, 95%CI 0.092-0.829, p=0.524), while long term use of OCP was associated with increased risk of breast cancer (OR=0.297, 95%CI 0.158-0.557, p=0.001), with higher association for those who used 10 years or more of OCPs (OR=0.282, 95%CI 0.095-0.835, p=0.02). Age at first use of OCPs had no effect on breast cancer risk (p=0.452) or age at diagnosis (p=0.074). Conclusions: Prolonged use of OC (more than 10 years) may be associated with increased risk of breast cancer in Saudi women. Larger population based studies are needed to confirm this finding in this population.

• 한국콘텐츠학회논문지
• /
• 제16권7호
• /
• pp.348-358
• /
• 2016

본 연구에서는 수도권 인구를 분석하여 도시 성장주기 변화를 밝히고, 각 권역별 특성을 파악해보고자 한다. 이를 위해 최근 일본에서 활발히 연구되고 있는 도시 성장주기 방법론인 ROXY 지수를 적용하였다. 분석결과, 중부지역, 남부지역, 수도권 전체적인 측면에서는 집중화 가속단계로 옮겨가려 하고 있으며, 교외화 단계에서 새로운 단계인 도심회귀로 전환될 가능성이 높은 것으로 나타났다. 또한, 교외지역인 북부지역과 동부지역에서는 현재 탈중심화 가속단계로 진행되었고 앞으로 탈집중화 감속단계로 전환될 것으로 예측되었다. 이를 통한 시사점으로는 수도권에서도 도시순환주기의 변화방향과 속도를 연계해 지역정비에 관한 정책대응을 실시하는 것이 필요할 것으로 판단된다. 본 연구의 결과는 향후 장기적인 수도권의 성장 및 쇠퇴를 가늠해 볼 수 있는 기초자료로 활용될 수 있을 것이다.

• 환경영향평가
• /
• 제22권3호
• /
• pp.195-201
• /
• 2013

Local governments are establishing their own greenhouse gas reduction goal and are playing a important role to respond to climatic changes. However, there are difficulties in quantitative analyses such as estimation of future greenhouse gas emission and computation of reduction potential, which are procedures required to establish mid to long term strategies to realize of low carbon society by each local governments. Also, reduction measures must reflect characteristics of each local government, since the reduction power of each local government can differ according to characteristics of each. In order to establish strategies that reflect characteristics of local governments, types of greenhouse gas emission from cities were classified largely into residential city, commercial city, residential commercial city, agriculture and fishery city, convergence city, and industrial city. As a result of analyzing basic unit of greenhouse gas emission by local government during 2007 in terms of per population, household and GRDP based on the type classification, significant results were deduced for each type. To manage the amount of the national greenhouse gas, reduction measures should be focused on the local governments that emits more than the average of each type's GHG emission.