• Title/Summary/Keyword: weakening trend

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Trends of Upper Jet Streams Characteristics (Intensity, Altitude, Latitude and Longitude) Over the Asia-North Pacific Region Based on Four Reanalysis Datasets (재분석자료들을 활용한 아시아-북태평양 상층제트의 강도(풍속) 및 3차원적 위치 변화 경향)

  • So, Eun-Mi;Suh, Myoung-Seok
    • Atmosphere
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    • v.27 no.1
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    • pp.1-16
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    • 2017
  • In this study, trends of upper jet stream characteristics (intensity, altitude, latitude, and longitude) over the Asia-North Pacific region during the recent 30 (1979~2008) years were analyzed by using four reanalysis datasets (CFSR, ERA-Int., JRA-55, MERRA). We defined the characteristics of upper jet stream as the averages of mass weighted wind speed, mass-flux weighted altitude, latitude and longitude between 400 and 100 hPa. Due to the vertical averaging of jet stream characteristics, our results reveal a weaker spatial variabilities and trends than previous studies. In general, the four reanalysis datasets show similar jet stream properties (intensity, altitude, latitude and longitude) although the magnitude and trends are slightly different among the reanalysis datasets. The altitude of MERRA is slightly higher than that of others for all seasons. The domain averaged intensity shows a weakening trend except for winter and the altitude of jet stream shows an increasing trend for all seasons. Also, the meridional trend of jet core shows a poleward trend for all seasons but it shows a contrasting trend, poleward trend in the continental area but equatorward trend in the Western Pacific region during summer. The zonal trend of jet core is very weak but a relatively strong westward trend in jet core except for spring and winter. The trends of jet stream characteristics found in this study are thermodynamically consistent with the global warming trends observed in the Asia-Pacific region.

Long-Term Trend of Surface Wind Speed in Korea: Anemometer Height Adjustment (한반도 지상 풍속의 장기 추세 분석: 풍속계 고도 보정)

  • Choi, Yeong-Ju;Park, Chang-Hyun;Son, Seok-Woo;Lee, Jae-Won;Hong, Dong-Chan
    • Atmosphere
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    • v.31 no.1
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    • pp.101-112
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    • 2021
  • The long-term trend of surface wind speed in Korea is examined for 31 KMA weather stations from 1985 to 2019. Most stations, except Daegwallyeong, have several times of anemometer height changes from tens of centimeters to several meters. To minimize such height change effect on long-term wind trend, the present study adjusts anemometer height in each station to the standard height of 10 m using the power-law wind profile. This adjustment results in non-negligible trend change. For instance, the increasing surface wind speed at Suwon station, which has six times of anemometer height changes in a range of 0.8 m to 20 m, is weakened up to 67% and becomes statistically insignificant. Likewise, the decreasing trend at Andong station, with three times of anemometer height changes in a range of 10 m to 15.5 m, is weakened up to 66%. A similar weakening in long-term trend is observed in most stations regardless of positive and negative trends. However, due to the cancellation between weakened negative trends and weakened positive trends, the station-averaged wind speed trend in Korea does not change much. This result suggests that anemometer height adjustment is crucial for evaluating local wind speed trend but its impact on nation-wide wind speed trend is rather minor.

Long-term Variability of Sea Surface Temperature in the East China Sea: A Review (동중국해 표층수온의 장기 변동성: 종설)

  • Lee, Jae Hak;Kim, Cheol-Ho
    • Ocean and Polar Research
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    • v.35 no.2
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    • pp.171-179
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    • 2013
  • The long-term variability of sea surface temperature in the East China Sea was reviewed based mainly on published literatures. Though the quantitative results are not the same, it is generally shown that sea surface temperature is increasing especially in recent years with the rate of increase about $0.03^{\circ}C$/year. Other meaningful results presented in the literatures is that the difference of water properties between layers upper and lower than the thermocline in summer shows an increasing trend both in temperature and salinity, suggesting that the stratification has been intensified. As a mechanism by which to evaluate the wintertime warming trend in the region, the weakening of wind strength, which is related to the variation of sea level pressure and atmospheric circulation in the western North Pacific and northern Asian continent, is suggested in the most of related studies.

Slip Movement Simulations of Major Faults Under Very Low Strength

  • Park, Moo-Choon;Han, Uk
    • Economic and Environmental Geology
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    • v.33 no.1
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    • pp.61-75
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    • 2000
  • Through modeling fault network using thin plate finite element technique in the San Andreas Fault system with slip rate over 1mm/year, as well as elevation, heat flow, earthquakes, geodetic data and crustal thickness, we compare the results with velocity boundary conditions of plate based on the NUVEL-1 plate model and the approximation of deformation in the Great Basin region. The frictional and dislocation creep constants of the crust are calculated to reproduce the observed variations in the maximum depth of seismicity which corresponds to the temperature ranging from $350^{\circ}C$ to $410^{\circ}C$. The rheologic constants are defined by the coefficient of friction on faults, and the apparent activation energy for creep in the lower crust. Two parameters above represent systematic variations in three experiments. The pattern of model indicates that the friction coefficient of major faults is 0.17~0.25. we test whether the weakness of faults is uniform or proportional to net slip. The geologic data show a good agreement when fault weakness is a trend of an additional 30% slip dependent weakening of the San Andreas. The results of study suggest that all weakening is slip dependent. The best models can be explained by the available data with RMS mismatch of as little as 3mm/year, so their predictions can be closely related with seismic hazard estimation, at least along faults where no data are available.

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A Trend Analysis of Changes in Housework due to Technological Innovation and Family Change

  • LEE, Hyun-Ah;KWON, Soonbum
    • East Asian Journal of Business Economics (EAJBE)
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    • v.10 no.1
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    • pp.109-121
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    • 2022
  • Purpose - This study attempted to analyze news big data in order to examine the trend of change in housework due to technological innovation and family changes. Research design, data, and methodology - News big data was collected from Bigkinds for the purpose of trend analysis. A total of 8,270 articles containing 'housework' were extracted from news articles between January 1, 1990 and December 31, 2021. 11 general daily newspapers and 8 business newspapers were selected and were analyzed by dividing them into five-year units. Result - The change of trends in housework that appeared through news big data analysis can be summarized as below. First, the tendency to regard housework as work of women or housewives is gradually weakening. Instead, the centrality of connection with double income is increasing. Second, there is a tendency to strengthen the institutional approach to evaluation of the productivity of housework. Third, the possibility of market substitution for housework is expanding. Conclusion - In the era of the 4th industrial revolution, examining the impact of technological innovation and family change on housework not only enables the prospect of an industry, but also provides implications for policies related to housework. In addition, this study is differentiated in that it contributed to expand the field of housework research previously limited to analyzing survey data.

Climate Change-Induced Physical Risks' Impact on Korean Commercial Banks and Property Insurance Companies in the Long Run (기후변화의 위험이 시중은행과 손해보험에 장기적으로 미치는 영향)

  • Seiwan Kim
    • Atmosphere
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    • v.34 no.2
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    • pp.107-121
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    • 2024
  • In this study, we empirically analyzed the impact of physical risks due to climate change on the soundness and operational performance of the financial industry by combining economics and climatology. Particularly, unlike previous studies, we employed the Seasonal-Trend decomposition using LOESS (STL) method to extract trends of climate-related risk variables and economic-financial variables, conducting a two-stage empirical analysis. In the first stage estimation, we found that the delinquency rate and the Bank for International Settlement (BIS) ratio of commercial banks have significant negative effects on the damage caused by natural disasters, frequency of heavy rainfall, average temperature, and number of typhoons. On the other hand, for insurance companies, the damage from natural disasters, frequency of heavy rainfall, frequency of heavy snowfall, and annual average temperature have significant negative effects on return on assets (ROA) and the risk-based capital ratio (RBC). In the second stage estimation, based on the first stage results, we predicted the soundness and operational performance indicators of commercial banks and insurance companies until 2035. According to the forecast results, the delinquency rate of commercial banks is expected to increase steadily until 2035 under assumption that recent years' trend continues until 2035. It indicates that banks' managerial risk can be seriously worsened from climate change. Also the BIS ratio is expected to decrease which also indicates weakening safety buffer against climate risks over time. Additionally, the ROA of insurance companies is expected to decrease, followed by an increase in the RBC, and then a subsequent decrease.

The Study development of body balance function rehabilitation training equipment (인체평형기능 재활훈련장치의 개발에 관한 연구)

  • O, J.Y.;Kim, Dong-Wook
    • Proceedings of the KIEE Conference
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    • 2002.11c
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    • pp.422-425
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    • 2002
  • Position balance control refers to ability that is kept bodily center of gravity under minimum position shake on surface of land. Patients who an injury of brain, a wound of the central nervous system or weakening of leg muscular power is fallen are trend increasing steadily by the car accident body balance function is on an increasing trended. These patients have difficulty in position balance control, receive big restriction walk and life style. This research composed to do body balance function rehabilitation training which elevate leg muscular power using step machine. And expect to become effective rehabilitation training device because measuring bodily pressure center using Force Platform and do so that can confirm training result easily as that is monitor.

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Agricultural land use in less favored areas in Japan and Measures against Abandoned cultivated land

  • Takuya, Hashiguchi
    • Journal of Korean Society of Rural Planning
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    • v.15 no.3
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    • pp.81-87
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    • 2009
  • It may be said that a farmer's crisis deepens from the number of farm households and a trend of the number of cultivated land of the farmer attracting attention for the most fundamental numerical value of the Census of Agriculture 2005. A rate of decline of number of farm households seems to have been stopped, but expansion lasts a number of farm households rate of decline. I can, so to speak, watch weakening of flatland area and luck of mountainous areas and a situation to say if I look in that according to classification agricultural area. I can nominate the effect of a direct payment system for farmers in hilly and mountainous areas enforced in 2000 for the background. It is located in case of the policy introduced preceding it while the rural community and the community including the urban area being paid attention as the last resort of a regional reproduction now. In particular, the character as the village activation subsidy has been strengthened in case of the 2nd stage institutional revise.

Changes of Internal Labor Market in Firms and Incentives for Investment in Human Resource Developments (기업 내부노동시장 변화와 인적자원개발 투자 유인)

  • Bai, Jin Han
    • Journal of Labour Economics
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    • v.41 no.1
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    • pp.83-124
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    • 2018
  • In this study, with the data of Human Capital Corporate Panel(HCCP) we find that the explaining power of the new hiring rate of experienced regular workers is very strong and statistically significant as a main causal factor to the decreasing trend of investment on education and training for workers in corporates, which means a sign of weakening of the internal labor market. Possibility of wage penalty from switching jobs has been weakened considerably too. The effective alternative policy measures to the weakening or laxity of the internal labor markets and whereby followed reduction in investment on education and training for workers in corporates are construction of social system outside of individual corporates to upbring field-tailored manpower of high quality for young generations and small and medium sized enterprises.

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Effect of RBS on seismic performance of prefabricated steel-concrete composite joints

  • Zhen Zhu;Haitao Song;Mingchi Fan;Hao Yu;Chenglong Wu;Chunying Zheng;Haiyang Duan;Lei Wang
    • Steel and Composite Structures
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    • v.52 no.4
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    • pp.405-418
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    • 2024
  • To study the influence of different reduced beam section (RBS) on the mechanical performance of modular boltedwelded hybrid connection joints (MHCJs), this article uses ABAQUS to establish and verify the finite element model (FEM) of the test specimens on the basis of quasi-static test research. Based on, 14 joint models featuring different RBS are devised to evaluate their influence on seismic behavior, such as joint failure mode, bending moment (M)-rotation angle (θ) curve, ductility, and energy consumption. The results indicate that when the flange and web are individually weakened, they alleviate to some extent the concentrated stress of the core module (CM) and column end steel skeleton in the joint core area, but both increase the stress on the flange connecting plate (FCP). At the same time, the impact of both on seismic performance such as bearing capacity, stiffness, and energy consumption is relatively small. When simultaneously weakening the flange and web of the steel beam, forming plastic hinges at the weakened position of the beam end, significantly alleviated the stress concentration of the CM and the damage at the FCP, improving the overall deformation and energy consumption capacity of joints. But as the weakening size of the web increases, the overall bearing capacity of the joint shows a decreasing trend.