• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.1
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• pp.115-119
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• 2014

When the number of items of same type of industrial property is quite large, calculating depreciation for a group of such item may be more efficient than depreciating each item separately. Also, predicting the service life of a specific individual unit is very difficult to do with any degree of accuracy. Estimating the probable average service life (PASL) of many units (or dollars) is not an easy task; however, an average life of many units can probably be predicted with a much higher degree of accuracy than the life of some particular unit. Using the average of many units allows for some units having relatively short lives and some units having relatively long lives without specifying whether a particular unit will have a short or a long life. If the life of each vintage in an account are not estimated, then the broad group procedure can be used. The broad group procedure depreciates the several vintage in an account as a single group. The PASL for this procedure is the estimate of the average of lives of the individual dollars in the group. If the estimated PASL's of the vintages are not the same, then a weighted average PASL would have to be calculated for each calendar year. In this paper, we illustrate the calculations of accrual rates and the annual depreciation charge for each of the calendar years by the broad group depreciation procedure.

• Journal of Environmental Science International
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• v.11 no.3
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• pp.247-255
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• 2002

Indoor and outdoor nitrogen dioxide (NO$_2$) concentrations were measured and compared with measurements of personal exposures of 95 persons in Seoul, Korea and 57 persons in Brisbane, Australia, respectively. Time activity diary was used to determine the impact on NO$_2$ exposure assessment and microenvironmental model to estimate the personal NO$_2$ exposure. Most people both Seoul and Brisbane spent their times more than 90% of indoor and more than 50% in home, respectively. Personal NO$_2$ exposures were significantly associated with indoor NO$_2$ levels with Pearson coefficient of 0.70 (p＜0.01) and outdoor NO$_2$ levels with Pearson coefficient of 0.66 (p＜0.01) in Seoul and of 0.51 (p＜0.01) and of 0.33 (p＜0.05) in Brisbane, respectively. Using microenvironmental model by time weighted average model, personal NO$_2$ exposures were estimated with NO$_2$ measurements in indoor home, indoor office and outdoor home. Estimated NO$_2$ measurements were significantly correlated with measured personal exposures (r = 0.69, p＜0.001) in Seoul and in Brisbane (r = 0.66, p＜0.001), respectively. Difference between measured and estimated NO$_2$ exposures by multiple regression analysis was explained that NO$_2$ levels in near workplace and other outdoors in Seoul (p = 0.023), and in transportation in Brisbane (p = 0.019) affected the personal NO$_2$ exposures.

• Journal of the Korean GEO-environmental Society
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• v.6 no.2
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• pp.31-38
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• 2005

Flowable fills are self-leveling, liquid-like materials, and self-compacting to 95-100% of the maximum unit weight. Benefits of flowable fills include limited required labor, accelerated construction, ready placement at inaccessible locations, and the ability to be manually re-excavated. Applications for flowable fills include utility trenches, building excavations, underground storage tanks, abandoned sewers and utility lines, and filling underground mine shafts The objective of this study is to estimate engineering property of flowable fills made of soil mixed with recycled stylofoam and stabilizer for using geotechnical field. For this study, the uniaxial compression test, flowable test, and model tests were performed. Based on the results of the tests, the following conclusions are : fills made of soil mixed with recycled stylofoam and stabilizer can be used as flowable fills, minimum stabilizer quantity for using flowable fills ranges from 1.0($kN/m^3$) to 1.2 ($kN/m^3$).

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.6
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• pp.51-62
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• 2020

The objective of this study was to estimate an optimum ecological flow rate in the Banbyeon stream based on the two representative fish species. Hydraulic stream environment was simulated with HEC-RAS for two water flow regimes and used for the PHABSIM hydraulic simulation. A dominant species of Zacco platypus and an endemic species of Squalidus chankaensis tsuchigae were selected as the representative fishes whose habitat conditions were evaluated for the spawning and adult stages. Weighted usable area (WUA) was estimated based on habitat suitability index (HSI) and PHABSIM habitat simulation. Overall deep water zone in the stream demonstrated greater WUA which implies better habitat status. The estimated WUA for Zacco platypus as the dominant species was about five times greater than Squalidus chankaensis tsuchigae at the stream flow of 12 ㎥/s. The optimum ecological flow rates were 15 ㎥/s and 25 ㎥/s for the respective spawning and adult stages of Zacco platypus, while 5 ㎥/s was estimated for both the life cycles of Squalidus chankaensis tsuchigae. Assuming that the dominant species may survive better in wider flow regimes, the optimum ecological flow rate should be determined rater based on the endemic species and flow rate of 5 ㎥/s was suggested for the Banbyeon stream.

• Tunnel and Underground Space
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• v.15 no.3 s.56
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• pp.195-212
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• 2005

Surface subsidence which occurs with several reasons, such as collapse of gangway, discharge of groundwater, compaction of weak rock mass, and tunnel excavation in shallow depth, gives rise to a serious problem in national infra-structures. In this study, therefore, the mechanism of subsidence has been examined numerically to overcome the passive approach on subsidence occurrence area. With many kinds of numerical studies, the major geotechnical parameters have been selected and the weighted values have been defined for each parameters. Also the authors developed the numerical program which can estimate the possibility of subsidence occurrence, and proposed the decision method for objective and quantitative guideline. It is anticipated that this research will be helpful to establish the hazard map on subsidence region.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.164-174
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• 2015

In a real scenario, radiometric change has frequently occurred in the stereo image acquisition process using multiple cameras with geometric characteristics or moving a single camera because it has different camera parameters and illumination change. Conventional stereo matching algorithms have a difficulty in finding correct corresponding points because it is assumed that corresponding pixels have similar color values. In this paper, we present a new method based on the local descriptor reflecting intensity, gradient and texture information. Furthermore, an adaptive weight for local descriptor based on the entropy is applied to estimate correct corresponding points under radiometric variation. The proposed method is tested on Middlebury datasets with radiometric changes, and compared with state-of-the-art algorithms. Experimental result shows that the proposed scheme outperforms other comparison algorithms around 5% less matching error on average.

• Journal of Climate Change Research
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• v.8 no.2
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• pp.125-143
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• 2017

This study is conducted to estimate potential evapotranspiration of 10 weather observing systems in Andong Dam watershed with FAO56 Penman-Monteith (FAO56 PM) methodology using the meteorological data from 2013 to 2014. Also, assuming that there is no solar radiation data, humidity data or wind speed data, the potential evapotranspiration was estimated by FAO56 PM and the results were evaluated to discuss whether the methodology is applicable when meteorological dataset is not available. Then, the potential evapotranspiration was estimated with Hargreaves method and compared with the potential evapotranspiration estimated by FAO56 PM only with the temperature dataset. As to compare the potential evapotranspiration estimated from the complete meteorological dataset and that estimated from limited dataset, statistical analysis was performed using the Root Mean Square Error (RMSE), the Mean Bias Error (MBE), the Mean Absolute Error (MAE) and the coefficient of determination ($R^2$). Also the Inverse Distance Weighted (IDW) method was performed to conduct spatial analysis. From the result, even when the meteorological data is limited, FAO56 PM showed relatively high accuracy in calculating potential evapotranspiration by estimating the meteorological data.

• Ecology and Resilient Infrastructure
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• v.6 no.1
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• pp.58-68
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• 2019

This present study conducted the impact of the restoration of low-flow channel on fish habitat in a reach of the Wonju Stream, Korea. The target species were Zacco koreanus, a dominant species in the middle- and upper-stream of Wonju Stream. The River2D model was used for the computation of the flow and the habitat suitability index model was used to estimate the quantity and quality of fish habitat using habitat suitability curves. In order to restore the study area, the low-flow channel was identified through the bankfull discharge of the study reach, and the best hydraulic section was designed. In addition, various restoration techniques were applied to the low-flow channel through rocks, pool/riffle structures, and the change of the channel width. Simulation results indicated that the restoration of the best hydraulic section effects decreased habitat suitability for the target species. However, when various restoration techniques were applied, the WUA (Weighted Usable Area) was improved by about 11%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.11
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• pp.1468-1473
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• 2018

The importance of communication and data processing is increasing with the advance of the Fourth Industrial Revolution. Hence, the importance of video and data processing technologies, which directly influence the accuracy and reliability of equipment, is also increasing. In this research report we propose an algorithm for calculating the final output by estimating the standard deviation and estimate required for removing AWGN while adapting to changes in the frequency factors of video. This algorithm calculates the final output by checking an estimated value against the effective pixel range, which is obtained from the standard deviation of mask factors. Subsequently, the weighted value is computed, taking into account the filter output. To evaluate the functionality of this algorithm, it is compared with the most-commonly used present method through simulation. The simulation results show that the important features of the image are preserved and efficient noise cancellation performance is demonstrated.

• Journal of Preventive Medicine and Public Health
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• v.52 no.3
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• pp.147-153
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• 2019

Objectives: The purpose of this study was to evaluate the association between body mass index (BMI) and severe lower urinary tract symptoms (LUTS) in Korean males. Methods: This study was conducted on males aged ${\geq}50years$ who participated in the 2011 Korean Community Health Survey. LUTS severity was assessed using the Korean version of the International Prostate Symptom Score (IPSS) questionnaire, and was dichotomized as severe (IPSS >19) and non-severe ($IPSS{\leq}19$). BMI was divided into 6 categories: <18.5, 18.5-22.9, 23.0-24.9, 25.0-27.4, 27.5-29.9, and ${\geq}30.0kg/m^2$. To evaluate the relationship between BMI and LUTS, a survey-weighted multivariate Poisson regression analysis was performed to estimate prevalence rate ratios (PRRs). Age, smoking status, alcohol intake, physical activity, educational level, household income, and comorbidities were adjusted for in the multivariate model. Results: A U-shaped relationship was detected between BMI and severe LUTS. Compared with a BMI of $23.0-24.9kg/m^2$, the PRR for a BMI < $18.5kg/m^2$ was 1.65 (95% confidence interval [CI], 1.35 to 2.02), that for a BMI of $18.5-22.9kg/m^2$ was 1.25 (95% CI, 1.09 to 1.44), that for a BMI of $25.0-27.4kg/m^2$ was 1.20 (95% CI, 1.00 to 1.45), that for a BMI of $27.5-29.9kg/m^2$ was 1.11 (95% CI, 0.83 to 1.47), and that for a BMI ${\geq}30.0kg/m^2$ was 1.85 (95% CI, 1.18 to 2.88). Conclusions: This study showed that both high and low BMI were associated with severe LUTS.