• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.1
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• pp.126-134
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• 1999

In this paper, a new error compensating technique for form-error compensation of rough-surface profile obtained by contact stylus profilometer is proposed. By the method, the real contact points of rough-surface and diamond stylus can be estimated and the measured profile data corrected. To verify the compensation effect, the properties(Ra, RMS, Kurtosis, Skewness) of measured profile data and compensated data were compared. And, the cumulative RMS slope was proposed to assess the compensated effect of upper area of profile. The results show that the measuring error could be compensated very well in amplitude parameters and in proposed cumulative RMS slope by the developed form-error compensating technique.

• Safety and Health at Work
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• v.4 no.2
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• pp.105-110
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• 2013

Background: To determine the influence of lifting speed and type on peak and cumulative back compressive force (BCF) and shoulder moment (SM) loads during symmetric lifting. Another aim of the study was to compare static and dynamic lifting models. Methods: Ten male participants performed a floor-to-shoulder, floor-to-waist, and waist-to-shoulder lift at three different speeds [slow (0.34 m/s), medium (0.44 m/s), and fast (0.64 m/s)], and with two different loads [light (2.25 kg) and heavy (9 kg)]. Two-dimensional kinematics and kinetics were determined. A three-way repeated measures analysis of variance was used to calculate peak and cumulative loading of BCF and SM for light and heavy loads. Results: Peak BCF was significantly different between slow and fast lifting speeds (p < 0.001), with a mean difference of 20% between fast and slow lifts. The cumulative loading of BCF and SM was significantly different between fast and slow lifting speeds (p < 0.001), with mean differences ${\geq}80%$. Conclusion: Based on peak values, BCF is highest for fast speeds, but the BCF cumulative loading is highest for slow speeds, with the largest difference between fast and slow lifts. This may imply that a slow lifting speed is at least as hazardous as a fast lifting speed. It is important to consider the duration of lift when determining risks for back and shoulder injuries due to lifting and that peak values alone are likely not sufficient.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.4
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• pp.52-59
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• 2000

This study was carried out to find out effect of by-product gypsum on reducing soil erosion at the sloping burned area at Sampo-ri, Gosung-gun in Kangwon-province during the period between June 28 and Sept. 30, 2000. Four experimental plots ($1.2m{\times}10m$) were prepared at the study area with slopes $15^{\circ}{\sim}18^{\circ}$ where forest fire took place twice during last 4 years. Phosphogypsum (PG) was applied to the soils of the 4 plots at the rates of 0 (control), 5, 7.5, and 10 ton/ha, respectively. Amount of rainfall, runoff, and soil loss were measured 7 times during the study. In the beginning, the amounts of runoff and soil loss from the PG treated plots were not different from those from the control plot due to steepness of the plots. However, the difference between the amount of runoff and soil loss from the PG treated plots and those from the control became apparent over time. The effect of PG treatment lasted until at least 870 mm of rainfall. Compared to the cumulative runoff from the control plot, the cumulative runoff from the plots treated with 5, 7.5, and 10 ton/ha PG decreased 7%, 31 %, and 35%, respectively. The cumulative soil loss from the plots treated with 5, 7.5, and 10 ton/ha PG decreased 44%, 53%, and 77% compared to that from the control plot. Strong acidity of PG (pH 2.0~2.5) did not affect the acidity of the soil and runoff.

• The Journal of Internal Korean Medicine
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• v.43 no.3
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• pp.413-422
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• 2022

Objectives: To investigate the weight loss effect of Gambi-tang in obese and overweight adults. Methods: From September 1, 2016 to December 31, 2021, a retrospective chart analysis was conducted on adult men and women who were prescribed Gambi-tang to address obesity and overweight in the National Medical Center (NMC). Partial analysis by age, obesity (Body Mass Index, BMI), duration of dose, and cumulative dose was also conducted. Results: The weight and BMI of the study subjects showed a significant decrease of more than 5% on average before and after treatment. In an analysis of age, significant differences by age could not be confirmed. In the analysis by obesity level, the effect of reducing weight, body fat, and abdominal fat rates in the obese and highly obese groups was greater than in the normal and overweight groups. There was no significant difference by group in the analysis by dosage period. In the analysis by cumulative dose, the greater the cumulative dose up to 1,800 g, the greater the decrease in weight and body fat. The side effect that patients appealed to the most was misjudgment, but not to a serious extent. Conclusions: Gambi-tang has been shown to be effective in weight and body fat loss for both obese and overweight adult men and women.

• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.331-337
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• 2022

The length of optical fiber in dispersion-managed link combined with optical phase conjugation to compensate for signal distortion caused by chromatic dispersion and nonlinear Kerr effect is a major factor determining the compensation effectiveness. The dispersion-managed link consists of several fiber spans in which standard single mode fiber and dispersion compensating fiber are arranged. In this paper, the compensation effect in the link that changes residual dispersion per span only by adjusting the length of one type of optical fiber, which is different in the first half link and the second half link with respect to optical phase conjugator (OPC), has been investigated. It was confirmed that the best compensation for 960 Gb/s wavelength division multiplexed signal could be obtained in the dispersion-managed link, in which the cumulative dispersion profile is symmetric around the OPC, and the cumulative dispersion amount is all positive in the first half, and all the cumulative dispersion amount is distributed negatively in the second half.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.3
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• pp.554-566
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• 2014

This paper analyses the relationship between regional economic power defined as GRDP per capita and various socioeconomic variables such as fiscal variables(revenue, expenditure, etc.) as well as nonfiscal variables(population, ratio of old population, unemployment rate, dependency ration) using the pooling data of 16 local governments from 1998 to 2012. To put it concretely, following the Granger causality test, regression analysis has been done with the regional economic power being the dependent and variables which have either one or two direction causality being independent variables. And test of cumulative effects has been done with variables showing statistical significance in the regression analysis. Local tax revenues per capita, expenditures of social development per capita and median age have positive effects, while dependency ratio has negative effect on regional economy. And national subsidy per capita, local tax revenues per capita, expenditures of social development per capita and median age all have cumulative effects on regional economy.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.245-253
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• 2019

BACKGROUND: Weathering of bottom ash (BA) might induce change of its surface texture and pH and affect physical and chemical properties of soil associated with greenhouse gas emission, when it is applied to the arable soil. This study was conducted to determine effect of weathering of BA in mitigating emission of greenhouse gases from upland soil. METHODS AND RESULTS: In a field experiment, methane (CH₄), carbon dioxide (CO₂), and nitrous oxide (N₂O) emitted from the soil was periodically monitored using closed chamber. Three month-weathered BA and non-weathered BA were applied to an upland soil at the rates of 0, 200 Mg ha^-1. Maize (Zea mays L.) was grown from July 1_st to Oct 8_th in 2018. Both BAs did not affect cumulative CH₄ emission. Cumulative CO₂ emission were 23.1, 19.8, and 18.8 Mg/ha/100days and cumulative N₂O emission were 35.8, 20.9, and 17.7 kg/ha/100days for the control, non-weathered BA, and weathered BA, respectively. Weathering of BA did not decrease emission of greenhouse gases significantly, compared to the weathered BA in this study. In addition, both BAs did not decrease biomass yields of maize. CONCLUSION: BA might be a good soil amendment to mitigate emissions of CO₂ and N₂O from arable soil without adverse effect on crop productivity.

• Journal of Korean Society on Water Environment
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• v.34 no.6
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• pp.650-660
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• 2018

The objective of this study was to compare the rainfall-runoff characteristics in streams of classified urban and rural watershed using land use and population density. EMC (event mean concentration) of BOD, COD, TP and SS increased significantly in urban and rural watershed, but that of TN remained unchanged. Although there were no significant differences in EMC of BOD, COD, TN, TP depending on the watershed characteristics, EMC of BOD and COD significantly increased in the urban watershed, while EMC of TP increased in the rural watershed. In the urban watershed, the first flush time was faster and the first flush effect was stronger in BOD, COD, and TP. However, the difference between cumulative mass and cumulative volume was found to be less than 0.2 in the rural watershed, indicating a weak first flush effect. The discharged masses of BOD (70 %), COD (64 %), and TP (66 %) in the first flush of runoff were higher in urban watershed, while TN (67 %) was higher in rural watershed. The reproducibility of first flush time and the strength of first flush using CV (coefficient of variation) was found to be more reproducible for first flush time in both watersheds. In rural watershed, the CV value of first flush time for TP out of water quality parameters was lower. Whereas the CV values of first flush time for BOD, COD and TP in urban watersheds were similar.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.9
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• pp.2590-2608
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• 2023

The high-altitude and mobility characteristics of unmanned aerial vehicles (UAVs) have made them a key element of new radio systems, particularly because they can exceed the limits of terrestrial networks. However, at high altitudes, UAVs can be significantly affected by intercell interference at a high line-of-sight probability. To mitigate this drawback, we propose an algorithm that selects the optimal beam to reduce interference and maximize transmission efficiency. The proposed algorithm comprises two steps: constructing a user-location-based fingerprint database according to the user types presented herein and cooperative beam selection. Simulations were conducted using cellular cooperative downlink systems for analyzing the performance of the proposed method, and the signal-to-interference-plus-noise cumulative distribution function and spectral efficiency cumulative distribution function were used as performance analysis indicators. Simulation results showed that the proposed algorithm could reduce the effect of interference and increase the performance of the desired signal. Moreover, the algorithm could efficiently reduce overheads and system cost by reducing the amount of resources required for information exchange.

• Journal of Industrial Convergence
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• v.5 no.1
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• pp.45-59
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• 2007

This paper empirically examines the portfolio diversification effect using data from both KOSPI and KOSDAQ. In KOSPI market, portfolio diversification effect disappears when more than 18 stocks are added in the portfolio. About 63% of portfolio risk is eliminated. In KOSDAQ market, the maximum portfolio diversification effect is achieved when 17 stocks are at least included in a portfolio. The maximum cumulative risk reduction is 35%.